| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Alexander Block | 13483 | 38.49% | 19 | 5.14% |
| Filipe David Borba Manana | 10686 | 30.51% | 104 | 28.11% |
| David Sterba | 1918 | 5.48% | 34 | 9.19% |
| Omar Sandoval | 1696 | 4.84% | 13 | 3.51% |
| Josef Bacik | 1432 | 4.09% | 21 | 5.68% |
| Chris Mason | 1260 | 3.60% | 42 | 11.35% |
| Bingjing Chang | 941 | 2.69% | 5 | 1.35% |
| Robbie Ko | 648 | 1.85% | 8 | 2.16% |
| Jan Schmidt | 605 | 1.73% | 9 | 2.43% |
| Boris Burkov | 412 | 1.18% | 2 | 0.54% |
| Marcos Paulo de Souza | 298 | 0.85% | 2 | 0.54% |
| Jeff Mahoney | 233 | 0.67% | 7 | 1.89% |
| Li Dongyang | 196 | 0.56% | 1 | 0.27% |
| Mark Fasheh | 171 | 0.49% | 3 | 0.81% |
| Gabriel Niebler | 159 | 0.45% | 6 | 1.62% |
| Liu Bo | 102 | 0.29% | 7 | 1.89% |
| Kuanling Huang | 68 | 0.19% | 1 | 0.27% |
| Josef Whiter | 65 | 0.19% | 13 | 3.51% |
| Sage Weil | 61 | 0.17% | 2 | 0.54% |
| Stefan Behrens | 54 | 0.15% | 3 | 0.81% |
| Christoph Hellwig | 54 | 0.15% | 5 | 1.35% |
| Shilong Wang | 48 | 0.14% | 2 | 0.54% |
| Ilya Dryomov | 46 | 0.13% | 2 | 0.54% |
| Sweet Tea Dorminy | 40 | 0.11% | 2 | 0.54% |
| Robin Ruede | 30 | 0.09% | 1 | 0.27% |
| Qu Wenruo | 27 | 0.08% | 3 | 0.81% |
| Anand Jain | 25 | 0.07% | 2 | 0.54% |
| Tsutomu Itoh | 25 | 0.07% | 3 | 0.81% |
| Dan Carpenter | 23 | 0.07% | 2 | 0.54% |
| Alex Lyakas | 20 | 0.06% | 1 | 0.27% |
| Nikolay Borisov | 19 | 0.05% | 3 | 0.81% |
| Misono, Tomohiro | 18 | 0.05% | 1 | 0.27% |
| Dāvis Mosāns | 16 | 0.05% | 1 | 0.27% |
| Arne Jansen | 14 | 0.04% | 3 | 0.81% |
| Denis Efremov | 13 | 0.04% | 1 | 0.27% |
| Roman Anasal | 11 | 0.03% | 1 | 0.27% |
| Jann Horn | 11 | 0.03% | 1 | 0.27% |
| Eric Biggers | 9 | 0.03% | 3 | 0.81% |
| Goldwyn Rodrigues | 9 | 0.03% | 1 | 0.27% |
| Kees Cook | 9 | 0.03% | 1 | 0.27% |
| ruanjinjie | 8 | 0.02% | 1 | 0.27% |
| Matthew Wilcox | 7 | 0.02% | 2 | 0.54% |
| Li Zefan | 6 | 0.02% | 2 | 0.54% |
| Kirill A. Shutemov | 6 | 0.02% | 1 | 0.27% |
| Dmitry Antipov | 6 | 0.02% | 1 | 0.27% |
| Zheng Yan | 4 | 0.01% | 2 | 0.54% |
| Johannes Thumshirn | 3 | 0.01% | 1 | 0.27% |
| Dulshani Gunawardhana | 3 | 0.01% | 1 | 0.27% |
| Sahil Kang | 3 | 0.01% | 1 | 0.27% |
| Thomas Meyer | 3 | 0.01% | 1 | 0.27% |
| Ira Weiny | 3 | 0.01% | 1 | 0.27% |
| katrinzhou | 2 | 0.01% | 1 | 0.27% |
| Austin Kim | 2 | 0.01% | 1 | 0.27% |
| Genjian Zhang | 2 | 0.01% | 1 | 0.27% |
| Américo Wang | 2 | 0.01% | 1 | 0.27% |
| Michal Hocko | 2 | 0.01% | 1 | 0.27% |
| Stephen Rothwell | 2 | 0.01% | 1 | 0.27% |
| Andy Shevchenko | 2 | 0.01% | 1 | 0.27% |
| Chi Minghao | 1 | 0.00% | 1 | 0.27% |
| Colin Ian King | 1 | 0.00% | 1 | 0.27% |
| Andreas Gruenbacher | 1 | 0.00% | 1 | 0.27% |
| Masahiro Yamada | 1 | 0.00% | 1 | 0.27% |
| wangyugui | 1 | 0.00% | 1 | 0.27% |
| Andrea Gelmini | 1 | 0.00% | 1 | 0.27% |
| Nicholas D Steeves | 1 | 0.00% | 1 | 0.27% |
| Eric Sandeen | 1 | 0.00% | 1 | 0.27% |
| Total | 35029 | 370 |
// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2012 Alexander Block. All rights reserved. */ #include <linux/bsearch.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/sort.h> #include <linux/mount.h> #include <linux/xattr.h> #include <linux/posix_acl_xattr.h> #include <linux/radix-tree.h> #include <linux/vmalloc.h> #include <linux/string.h> #include <linux/compat.h> #include <linux/crc32c.h> #include <linux/fsverity.h> #include "send.h" #include "ctree.h" #include "backref.h" #include "locking.h" #include "disk-io.h" #include "btrfs_inode.h" #include "transaction.h" #include "compression.h" #include "xattr.h" #include "print-tree.h" #include "accessors.h" #include "dir-item.h" #include "file-item.h" #include "ioctl.h" #include "verity.h" #include "lru_cache.h" /* * Maximum number of references an extent can have in order for us to attempt to * issue clone operations instead of write operations. This currently exists to * avoid hitting limitations of the backreference walking code (taking a lot of * time and using too much memory for extents with large number of references). */ #define SEND_MAX_EXTENT_REFS 1024 /* * A fs_path is a helper to dynamically build path names with unknown size. * It reallocates the internal buffer on demand. * It allows fast adding of path elements on the right side (normal path) and * fast adding to the left side (reversed path). A reversed path can also be * unreversed if needed. */ struct fs_path { union { struct { char *start; char *end; char *buf; unsigned short buf_len:15; unsigned short reversed:1; char inline_buf[]; }; /* * Average path length does not exceed 200 bytes, we'll have * better packing in the slab and higher chance to satisfy * a allocation later during send. */ char pad[256]; }; }; #define FS_PATH_INLINE_SIZE \ (sizeof(struct fs_path) - offsetof(struct fs_path, inline_buf)) /* reused for each extent */ struct clone_root { struct btrfs_root *root; u64 ino; u64 offset; u64 num_bytes; bool found_ref; }; #define SEND_MAX_NAME_CACHE_SIZE 256 /* * Limit the root_ids array of struct backref_cache_entry to 17 elements. * This makes the size of a cache entry to be exactly 192 bytes on x86_64, which * can be satisfied from the kmalloc-192 slab, without wasting any space. * The most common case is to have a single root for cloning, which corresponds * to the send root. Having the user specify more than 16 clone roots is not * common, and in such rare cases we simply don't use caching if the number of * cloning roots that lead down to a leaf is more than 17. */ #define SEND_MAX_BACKREF_CACHE_ROOTS 17 /* * Max number of entries in the cache. * With SEND_MAX_BACKREF_CACHE_ROOTS as 17, the size in bytes, excluding * maple tree's internal nodes, is 24K. */ #define SEND_MAX_BACKREF_CACHE_SIZE 128 /* * A backref cache entry maps a leaf to a list of IDs of roots from which the * leaf is accessible and we can use for clone operations. * With SEND_MAX_BACKREF_CACHE_ROOTS as 12, each cache entry is 128 bytes (on * x86_64). */ struct backref_cache_entry { struct btrfs_lru_cache_entry entry; u64 root_ids[SEND_MAX_BACKREF_CACHE_ROOTS]; /* Number of valid elements in the root_ids array. */ int num_roots; }; /* See the comment at lru_cache.h about struct btrfs_lru_cache_entry. */ static_assert(offsetof(struct backref_cache_entry, entry) == 0); /* * Max number of entries in the cache that stores directories that were already * created. The cache uses raw struct btrfs_lru_cache_entry entries, so it uses * at most 4096 bytes - sizeof(struct btrfs_lru_cache_entry) is 48 bytes, but * the kmalloc-64 slab is used, so we get 4096 bytes (64 bytes * 64). */ #define SEND_MAX_DIR_CREATED_CACHE_SIZE 64 /* * Max number of entries in the cache that stores directories that were already * created. The cache uses raw struct btrfs_lru_cache_entry entries, so it uses * at most 4096 bytes - sizeof(struct btrfs_lru_cache_entry) is 48 bytes, but * the kmalloc-64 slab is used, so we get 4096 bytes (64 bytes * 64). */ #define SEND_MAX_DIR_UTIMES_CACHE_SIZE 64 struct send_ctx { struct file *send_filp; loff_t send_off; char *send_buf; u32 send_size; u32 send_max_size; /* * Whether BTRFS_SEND_A_DATA attribute was already added to current * command (since protocol v2, data must be the last attribute). */ bool put_data; struct page **send_buf_pages; u64 flags; /* 'flags' member of btrfs_ioctl_send_args is u64 */ /* Protocol version compatibility requested */ u32 proto; struct btrfs_root *send_root; struct btrfs_root *parent_root; struct clone_root *clone_roots; int clone_roots_cnt; /* current state of the compare_tree call */ struct btrfs_path *left_path; struct btrfs_path *right_path; struct btrfs_key *cmp_key; /* * Keep track of the generation of the last transaction that was used * for relocating a block group. This is periodically checked in order * to detect if a relocation happened since the last check, so that we * don't operate on stale extent buffers for nodes (level >= 1) or on * stale disk_bytenr values of file extent items. */ u64 last_reloc_trans; /* * infos of the currently processed inode. In case of deleted inodes, * these are the values from the deleted inode. */ u64 cur_ino; u64 cur_inode_gen; u64 cur_inode_size; u64 cur_inode_mode; u64 cur_inode_rdev; u64 cur_inode_last_extent; u64 cur_inode_next_write_offset; bool cur_inode_new; bool cur_inode_new_gen; bool cur_inode_deleted; bool ignore_cur_inode; bool cur_inode_needs_verity; void *verity_descriptor; u64 send_progress; struct list_head new_refs; struct list_head deleted_refs; struct btrfs_lru_cache name_cache; /* * The inode we are currently processing. It's not NULL only when we * need to issue write commands for data extents from this inode. */ struct inode *cur_inode; struct file_ra_state ra; u64 page_cache_clear_start; bool clean_page_cache; /* * We process inodes by their increasing order, so if before an * incremental send we reverse the parent/child relationship of * directories such that a directory with a lower inode number was * the parent of a directory with a higher inode number, and the one * becoming the new parent got renamed too, we can't rename/move the * directory with lower inode number when we finish processing it - we * must process the directory with higher inode number first, then * rename/move it and then rename/move the directory with lower inode * number. Example follows. * * Tree state when the first send was performed: * * . * |-- a (ino 257) * |-- b (ino 258) * | * | * |-- c (ino 259) * | |-- d (ino 260) * | * |-- c2 (ino 261) * * Tree state when the second (incremental) send is performed: * * . * |-- a (ino 257) * |-- b (ino 258) * |-- c2 (ino 261) * |-- d2 (ino 260) * |-- cc (ino 259) * * The sequence of steps that lead to the second state was: * * mv /a/b/c/d /a/b/c2/d2 * mv /a/b/c /a/b/c2/d2/cc * * "c" has lower inode number, but we can't move it (2nd mv operation) * before we move "d", which has higher inode number. * * So we just memorize which move/rename operations must be performed * later when their respective parent is processed and moved/renamed. */ /* Indexed by parent directory inode number. */ struct rb_root pending_dir_moves; /* * Reverse index, indexed by the inode number of a directory that * is waiting for the move/rename of its immediate parent before its * own move/rename can be performed. */ struct rb_root waiting_dir_moves; /* * A directory that is going to be rm'ed might have a child directory * which is in the pending directory moves index above. In this case, * the directory can only be removed after the move/rename of its child * is performed. Example: * * Parent snapshot: * * . (ino 256) * |-- a/ (ino 257) * |-- b/ (ino 258) * |-- c/ (ino 259) * | |-- x/ (ino 260) * | * |-- y/ (ino 261) * * Send snapshot: * * . (ino 256) * |-- a/ (ino 257) * |-- b/ (ino 258) * |-- YY/ (ino 261) * |-- x/ (ino 260) * * Sequence of steps that lead to the send snapshot: * rm -f /a/b/c/foo.txt * mv /a/b/y /a/b/YY * mv /a/b/c/x /a/b/YY * rmdir /a/b/c * * When the child is processed, its move/rename is delayed until its * parent is processed (as explained above), but all other operations * like update utimes, chown, chgrp, etc, are performed and the paths * that it uses for those operations must use the orphanized name of * its parent (the directory we're going to rm later), so we need to * memorize that name. * * Indexed by the inode number of the directory to be deleted. */ struct rb_root orphan_dirs; struct rb_root rbtree_new_refs; struct rb_root rbtree_deleted_refs; struct btrfs_lru_cache backref_cache; u64 backref_cache_last_reloc_trans; struct btrfs_lru_cache dir_created_cache; struct btrfs_lru_cache dir_utimes_cache; }; struct pending_dir_move { struct rb_node node; struct list_head list; u64 parent_ino; u64 ino; u64 gen; struct list_head update_refs; }; struct waiting_dir_move { struct rb_node node; u64 ino; /* * There might be some directory that could not be removed because it * was waiting for this directory inode to be moved first. Therefore * after this directory is moved, we can try to rmdir the ino rmdir_ino. */ u64 rmdir_ino; u64 rmdir_gen; bool orphanized; }; struct orphan_dir_info { struct rb_node node; u64 ino; u64 gen; u64 last_dir_index_offset; u64 dir_high_seq_ino; }; struct name_cache_entry { /* * The key in the entry is an inode number, and the generation matches * the inode's generation. */ struct btrfs_lru_cache_entry entry; u64 parent_ino; u64 parent_gen; int ret; int need_later_update; int name_len; char name[]; }; /* See the comment at lru_cache.h about struct btrfs_lru_cache_entry. */ static_assert(offsetof(struct name_cache_entry, entry) == 0); #define ADVANCE 1 #define ADVANCE_ONLY_NEXT -1 enum btrfs_compare_tree_result { BTRFS_COMPARE_TREE_NEW, BTRFS_COMPARE_TREE_DELETED, BTRFS_COMPARE_TREE_CHANGED, BTRFS_COMPARE_TREE_SAME, }; __cold static void inconsistent_snapshot_error(struct send_ctx *sctx, enum btrfs_compare_tree_result result, const char *what) { const char *result_string; switch (result) { case BTRFS_COMPARE_TREE_NEW: result_string = "new"; break; case BTRFS_COMPARE_TREE_DELETED: result_string = "deleted"; break; case BTRFS_COMPARE_TREE_CHANGED: result_string = "updated"; break; case BTRFS_COMPARE_TREE_SAME: ASSERT(0); result_string = "unchanged"; break; default: ASSERT(0); result_string = "unexpected"; } btrfs_err(sctx->send_root->fs_info, "Send: inconsistent snapshot, found %s %s for inode %llu without updated inode item, send root is %llu, parent root is %llu", result_string, what, sctx->cmp_key->objectid, sctx->send_root->root_key.objectid, (sctx->parent_root ? sctx->parent_root->root_key.objectid : 0)); } __maybe_unused static bool proto_cmd_ok(const struct send_ctx *sctx, int cmd) { switch (sctx->proto) { case 1: return cmd <= BTRFS_SEND_C_MAX_V1; case 2: return cmd <= BTRFS_SEND_C_MAX_V2; case 3: return cmd <= BTRFS_SEND_C_MAX_V3; default: return false; } } static int is_waiting_for_move(struct send_ctx *sctx, u64 ino); static struct waiting_dir_move * get_waiting_dir_move(struct send_ctx *sctx, u64 ino); static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen); static int need_send_hole(struct send_ctx *sctx) { return (sctx->parent_root && !sctx->cur_inode_new && !sctx->cur_inode_new_gen && !sctx->cur_inode_deleted && S_ISREG(sctx->cur_inode_mode)); } static void fs_path_reset(struct fs_path *p) { if (p->reversed) { p->start = p->buf + p->buf_len - 1; p->end = p->start; *p->start = 0; } else { p->start = p->buf; p->end = p->start; *p->start = 0; } } static struct fs_path *fs_path_alloc(void) { struct fs_path *p; p = kmalloc(sizeof(*p), GFP_KERNEL); if (!p) return NULL; p->reversed = 0; p->buf = p->inline_buf; p->buf_len = FS_PATH_INLINE_SIZE; fs_path_reset(p); return p; } static struct fs_path *fs_path_alloc_reversed(void) { struct fs_path *p; p = fs_path_alloc(); if (!p) return NULL; p->reversed = 1; fs_path_reset(p); return p; } static void fs_path_free(struct fs_path *p) { if (!p) return; if (p->buf != p->inline_buf) kfree(p->buf); kfree(p); } static int fs_path_len(struct fs_path *p) { return p->end - p->start; } static int fs_path_ensure_buf(struct fs_path *p, int len) { char *tmp_buf; int path_len; int old_buf_len; len++; if (p->buf_len >= len) return 0; if (len > PATH_MAX) { WARN_ON(1); return -ENOMEM; } path_len = p->end - p->start; old_buf_len = p->buf_len; /* * Allocate to the next largest kmalloc bucket size, to let * the fast path happen most of the time. */ len = kmalloc_size_roundup(len); /* * First time the inline_buf does not suffice */ if (p->buf == p->inline_buf) { tmp_buf = kmalloc(len, GFP_KERNEL); if (tmp_buf) memcpy(tmp_buf, p->buf, old_buf_len); } else { tmp_buf = krealloc(p->buf, len, GFP_KERNEL); } if (!tmp_buf) return -ENOMEM; p->buf = tmp_buf; p->buf_len = len; if (p->reversed) { tmp_buf = p->buf + old_buf_len - path_len - 1; p->end = p->buf + p->buf_len - 1; p->start = p->end - path_len; memmove(p->start, tmp_buf, path_len + 1); } else { p->start = p->buf; p->end = p->start + path_len; } return 0; } static int fs_path_prepare_for_add(struct fs_path *p, int name_len, char **prepared) { int ret; int new_len; new_len = p->end - p->start + name_len; if (p->start != p->end) new_len++; ret = fs_path_ensure_buf(p, new_len); if (ret < 0) goto out; if (p->reversed) { if (p->start != p->end) *--p->start = '/'; p->start -= name_len; *prepared = p->start; } else { if (p->start != p->end) *p->end++ = '/'; *prepared = p->end; p->end += name_len; *p->end = 0; } out: return ret; } static int fs_path_add(struct fs_path *p, const char *name, int name_len) { int ret; char *prepared; ret = fs_path_prepare_for_add(p, name_len, &prepared); if (ret < 0) goto out; memcpy(prepared, name, name_len); out: return ret; } static int fs_path_add_path(struct fs_path *p, struct fs_path *p2) { int ret; char *prepared; ret = fs_path_prepare_for_add(p, p2->end - p2->start, &prepared); if (ret < 0) goto out; memcpy(prepared, p2->start, p2->end - p2->start); out: return ret; } static int fs_path_add_from_extent_buffer(struct fs_path *p, struct extent_buffer *eb, unsigned long off, int len) { int ret; char *prepared; ret = fs_path_prepare_for_add(p, len, &prepared); if (ret < 0) goto out; read_extent_buffer(eb, prepared, off, len); out: return ret; } static int fs_path_copy(struct fs_path *p, struct fs_path *from) { p->reversed = from->reversed; fs_path_reset(p); return fs_path_add_path(p, from); } static void fs_path_unreverse(struct fs_path *p) { char *tmp; int len; if (!p->reversed) return; tmp = p->start; len = p->end - p->start; p->start = p->buf; p->end = p->start + len; memmove(p->start, tmp, len + 1); p->reversed = 0; } static struct btrfs_path *alloc_path_for_send(void) { struct btrfs_path *path; path = btrfs_alloc_path(); if (!path) return NULL; path->search_commit_root = 1; path->skip_locking = 1; path->need_commit_sem = 1; return path; } static int write_buf(struct file *filp, const void *buf, u32 len, loff_t *off) { int ret; u32 pos = 0; while (pos < len) { ret = kernel_write(filp, buf + pos, len - pos, off); if (ret < 0) return ret; if (ret == 0) return -EIO; pos += ret; } return 0; } static int tlv_put(struct send_ctx *sctx, u16 attr, const void *data, int len) { struct btrfs_tlv_header *hdr; int total_len = sizeof(*hdr) + len; int left = sctx->send_max_size - sctx->send_size; if (WARN_ON_ONCE(sctx->put_data)) return -EINVAL; if (unlikely(left < total_len)) return -EOVERFLOW; hdr = (struct btrfs_tlv_header *) (sctx->send_buf + sctx->send_size); put_unaligned_le16(attr, &hdr->tlv_type); put_unaligned_le16(len, &hdr->tlv_len); memcpy(hdr + 1, data, len); sctx->send_size += total_len; return 0; } #define TLV_PUT_DEFINE_INT(bits) \ static int tlv_put_u##bits(struct send_ctx *sctx, \ u##bits attr, u##bits value) \ { \ __le##bits __tmp = cpu_to_le##bits(value); \ return tlv_put(sctx, attr, &__tmp, sizeof(__tmp)); \ } TLV_PUT_DEFINE_INT(8) TLV_PUT_DEFINE_INT(32) TLV_PUT_DEFINE_INT(64) static int tlv_put_string(struct send_ctx *sctx, u16 attr, const char *str, int len) { if (len == -1) len = strlen(str); return tlv_put(sctx, attr, str, len); } static int tlv_put_uuid(struct send_ctx *sctx, u16 attr, const u8 *uuid) { return tlv_put(sctx, attr, uuid, BTRFS_UUID_SIZE); } static int tlv_put_btrfs_timespec(struct send_ctx *sctx, u16 attr, struct extent_buffer *eb, struct btrfs_timespec *ts) { struct btrfs_timespec bts; read_extent_buffer(eb, &bts, (unsigned long)ts, sizeof(bts)); return tlv_put(sctx, attr, &bts, sizeof(bts)); } #define TLV_PUT(sctx, attrtype, data, attrlen) \ do { \ ret = tlv_put(sctx, attrtype, data, attrlen); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) #define TLV_PUT_INT(sctx, attrtype, bits, value) \ do { \ ret = tlv_put_u##bits(sctx, attrtype, value); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) #define TLV_PUT_U8(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 8, data) #define TLV_PUT_U16(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 16, data) #define TLV_PUT_U32(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 32, data) #define TLV_PUT_U64(sctx, attrtype, data) TLV_PUT_INT(sctx, attrtype, 64, data) #define TLV_PUT_STRING(sctx, attrtype, str, len) \ do { \ ret = tlv_put_string(sctx, attrtype, str, len); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) #define TLV_PUT_PATH(sctx, attrtype, p) \ do { \ ret = tlv_put_string(sctx, attrtype, p->start, \ p->end - p->start); \ if (ret < 0) \ goto tlv_put_failure; \ } while(0) #define TLV_PUT_UUID(sctx, attrtype, uuid) \ do { \ ret = tlv_put_uuid(sctx, attrtype, uuid); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) #define TLV_PUT_BTRFS_TIMESPEC(sctx, attrtype, eb, ts) \ do { \ ret = tlv_put_btrfs_timespec(sctx, attrtype, eb, ts); \ if (ret < 0) \ goto tlv_put_failure; \ } while (0) static int send_header(struct send_ctx *sctx) { struct btrfs_stream_header hdr; strcpy(hdr.magic, BTRFS_SEND_STREAM_MAGIC); hdr.version = cpu_to_le32(sctx->proto); return write_buf(sctx->send_filp, &hdr, sizeof(hdr), &sctx->send_off); } /* * For each command/item we want to send to userspace, we call this function. */ static int begin_cmd(struct send_ctx *sctx, int cmd) { struct btrfs_cmd_header *hdr; if (WARN_ON(!sctx->send_buf)) return -EINVAL; BUG_ON(sctx->send_size); sctx->send_size += sizeof(*hdr); hdr = (struct btrfs_cmd_header *)sctx->send_buf; put_unaligned_le16(cmd, &hdr->cmd); return 0; } static int send_cmd(struct send_ctx *sctx) { int ret; struct btrfs_cmd_header *hdr; u32 crc; hdr = (struct btrfs_cmd_header *)sctx->send_buf; put_unaligned_le32(sctx->send_size - sizeof(*hdr), &hdr->len); put_unaligned_le32(0, &hdr->crc); crc = crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size); put_unaligned_le32(crc, &hdr->crc); ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size, &sctx->send_off); sctx->send_size = 0; sctx->put_data = false; return ret; } /* * Sends a move instruction to user space */ static int send_rename(struct send_ctx *sctx, struct fs_path *from, struct fs_path *to) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; btrfs_debug(fs_info, "send_rename %s -> %s", from->start, to->start); ret = begin_cmd(sctx, BTRFS_SEND_C_RENAME); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, from); TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_TO, to); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } /* * Sends a link instruction to user space */ static int send_link(struct send_ctx *sctx, struct fs_path *path, struct fs_path *lnk) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; btrfs_debug(fs_info, "send_link %s -> %s", path->start, lnk->start); ret = begin_cmd(sctx, BTRFS_SEND_C_LINK); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, lnk); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } /* * Sends an unlink instruction to user space */ static int send_unlink(struct send_ctx *sctx, struct fs_path *path) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; btrfs_debug(fs_info, "send_unlink %s", path->start); ret = begin_cmd(sctx, BTRFS_SEND_C_UNLINK); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } /* * Sends a rmdir instruction to user space */ static int send_rmdir(struct send_ctx *sctx, struct fs_path *path) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; btrfs_debug(fs_info, "send_rmdir %s", path->start); ret = begin_cmd(sctx, BTRFS_SEND_C_RMDIR); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } struct btrfs_inode_info { u64 size; u64 gen; u64 mode; u64 uid; u64 gid; u64 rdev; u64 fileattr; u64 nlink; }; /* * Helper function to retrieve some fields from an inode item. */ static int get_inode_info(struct btrfs_root *root, u64 ino, struct btrfs_inode_info *info) { int ret; struct btrfs_path *path; struct btrfs_inode_item *ii; struct btrfs_key key; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = ino; key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret) { if (ret > 0) ret = -ENOENT; goto out; } if (!info) goto out; ii = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_inode_item); info->size = btrfs_inode_size(path->nodes[0], ii); info->gen = btrfs_inode_generation(path->nodes[0], ii); info->mode = btrfs_inode_mode(path->nodes[0], ii); info->uid = btrfs_inode_uid(path->nodes[0], ii); info->gid = btrfs_inode_gid(path->nodes[0], ii); info->rdev = btrfs_inode_rdev(path->nodes[0], ii); info->nlink = btrfs_inode_nlink(path->nodes[0], ii); /* * Transfer the unchanged u64 value of btrfs_inode_item::flags, that's * otherwise logically split to 32/32 parts. */ info->fileattr = btrfs_inode_flags(path->nodes[0], ii); out: btrfs_free_path(path); return ret; } static int get_inode_gen(struct btrfs_root *root, u64 ino, u64 *gen) { int ret; struct btrfs_inode_info info = { 0 }; ASSERT(gen); ret = get_inode_info(root, ino, &info); *gen = info.gen; return ret; } typedef int (*iterate_inode_ref_t)(int num, u64 dir, int index, struct fs_path *p, void *ctx); /* * Helper function to iterate the entries in ONE btrfs_inode_ref or * btrfs_inode_extref. * The iterate callback may return a non zero value to stop iteration. This can * be a negative value for error codes or 1 to simply stop it. * * path must point to the INODE_REF or INODE_EXTREF when called. */ static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_key *found_key, int resolve, iterate_inode_ref_t iterate, void *ctx) { struct extent_buffer *eb = path->nodes[0]; struct btrfs_inode_ref *iref; struct btrfs_inode_extref *extref; struct btrfs_path *tmp_path; struct fs_path *p; u32 cur = 0; u32 total; int slot = path->slots[0]; u32 name_len; char *start; int ret = 0; int num = 0; int index; u64 dir; unsigned long name_off; unsigned long elem_size; unsigned long ptr; p = fs_path_alloc_reversed(); if (!p) return -ENOMEM; tmp_path = alloc_path_for_send(); if (!tmp_path) { fs_path_free(p); return -ENOMEM; } if (found_key->type == BTRFS_INODE_REF_KEY) { ptr = (unsigned long)btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); total = btrfs_item_size(eb, slot); elem_size = sizeof(*iref); } else { ptr = btrfs_item_ptr_offset(eb, slot); total = btrfs_item_size(eb, slot); elem_size = sizeof(*extref); } while (cur < total) { fs_path_reset(p); if (found_key->type == BTRFS_INODE_REF_KEY) { iref = (struct btrfs_inode_ref *)(ptr + cur); name_len = btrfs_inode_ref_name_len(eb, iref); name_off = (unsigned long)(iref + 1); index = btrfs_inode_ref_index(eb, iref); dir = found_key->offset; } else { extref = (struct btrfs_inode_extref *)(ptr + cur); name_len = btrfs_inode_extref_name_len(eb, extref); name_off = (unsigned long)&extref->name; index = btrfs_inode_extref_index(eb, extref); dir = btrfs_inode_extref_parent(eb, extref); } if (resolve) { start = btrfs_ref_to_path(root, tmp_path, name_len, name_off, eb, dir, p->buf, p->buf_len); if (IS_ERR(start)) { ret = PTR_ERR(start); goto out; } if (start < p->buf) { /* overflow , try again with larger buffer */ ret = fs_path_ensure_buf(p, p->buf_len + p->buf - start); if (ret < 0) goto out; start = btrfs_ref_to_path(root, tmp_path, name_len, name_off, eb, dir, p->buf, p->buf_len); if (IS_ERR(start)) { ret = PTR_ERR(start); goto out; } BUG_ON(start < p->buf); } p->start = start; } else { ret = fs_path_add_from_extent_buffer(p, eb, name_off, name_len); if (ret < 0) goto out; } cur += elem_size + name_len; ret = iterate(num, dir, index, p, ctx); if (ret) goto out; num++; } out: btrfs_free_path(tmp_path); fs_path_free(p); return ret; } typedef int (*iterate_dir_item_t)(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, void *ctx); /* * Helper function to iterate the entries in ONE btrfs_dir_item. * The iterate callback may return a non zero value to stop iteration. This can * be a negative value for error codes or 1 to simply stop it. * * path must point to the dir item when called. */ static int iterate_dir_item(struct btrfs_root *root, struct btrfs_path *path, iterate_dir_item_t iterate, void *ctx) { int ret = 0; struct extent_buffer *eb; struct btrfs_dir_item *di; struct btrfs_key di_key; char *buf = NULL; int buf_len; u32 name_len; u32 data_len; u32 cur; u32 len; u32 total; int slot; int num; /* * Start with a small buffer (1 page). If later we end up needing more * space, which can happen for xattrs on a fs with a leaf size greater * then the page size, attempt to increase the buffer. Typically xattr * values are small. */ buf_len = PATH_MAX; buf = kmalloc(buf_len, GFP_KERNEL); if (!buf) { ret = -ENOMEM; goto out; } eb = path->nodes[0]; slot = path->slots[0]; di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item); cur = 0; len = 0; total = btrfs_item_size(eb, slot); num = 0; while (cur < total) { name_len = btrfs_dir_name_len(eb, di); data_len = btrfs_dir_data_len(eb, di); btrfs_dir_item_key_to_cpu(eb, di, &di_key); if (btrfs_dir_ftype(eb, di) == BTRFS_FT_XATTR) { if (name_len > XATTR_NAME_MAX) { ret = -ENAMETOOLONG; goto out; } if (name_len + data_len > BTRFS_MAX_XATTR_SIZE(root->fs_info)) { ret = -E2BIG; goto out; } } else { /* * Path too long */ if (name_len + data_len > PATH_MAX) { ret = -ENAMETOOLONG; goto out; } } if (name_len + data_len > buf_len) { buf_len = name_len + data_len; if (is_vmalloc_addr(buf)) { vfree(buf); buf = NULL; } else { char *tmp = krealloc(buf, buf_len, GFP_KERNEL | __GFP_NOWARN); if (!tmp) kfree(buf); buf = tmp; } if (!buf) { buf = kvmalloc(buf_len, GFP_KERNEL); if (!buf) { ret = -ENOMEM; goto out; } } } read_extent_buffer(eb, buf, (unsigned long)(di + 1), name_len + data_len); len = sizeof(*di) + name_len + data_len; di = (struct btrfs_dir_item *)((char *)di + len); cur += len; ret = iterate(num, &di_key, buf, name_len, buf + name_len, data_len, ctx); if (ret < 0) goto out; if (ret) { ret = 0; goto out; } num++; } out: kvfree(buf); return ret; } static int __copy_first_ref(int num, u64 dir, int index, struct fs_path *p, void *ctx) { int ret; struct fs_path *pt = ctx; ret = fs_path_copy(pt, p); if (ret < 0) return ret; /* we want the first only */ return 1; } /* * Retrieve the first path of an inode. If an inode has more then one * ref/hardlink, this is ignored. */ static int get_inode_path(struct btrfs_root *root, u64 ino, struct fs_path *path) { int ret; struct btrfs_key key, found_key; struct btrfs_path *p; p = alloc_path_for_send(); if (!p) return -ENOMEM; fs_path_reset(path); key.objectid = ino; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; ret = btrfs_search_slot_for_read(root, &key, p, 1, 0); if (ret < 0) goto out; if (ret) { ret = 1; goto out; } btrfs_item_key_to_cpu(p->nodes[0], &found_key, p->slots[0]); if (found_key.objectid != ino || (found_key.type != BTRFS_INODE_REF_KEY && found_key.type != BTRFS_INODE_EXTREF_KEY)) { ret = -ENOENT; goto out; } ret = iterate_inode_ref(root, p, &found_key, 1, __copy_first_ref, path); if (ret < 0) goto out; ret = 0; out: btrfs_free_path(p); return ret; } struct backref_ctx { struct send_ctx *sctx; /* number of total found references */ u64 found; /* * used for clones found in send_root. clones found behind cur_objectid * and cur_offset are not considered as allowed clones. */ u64 cur_objectid; u64 cur_offset; /* may be truncated in case it's the last extent in a file */ u64 extent_len; /* The bytenr the file extent item we are processing refers to. */ u64 bytenr; /* The owner (root id) of the data backref for the current extent. */ u64 backref_owner; /* The offset of the data backref for the current extent. */ u64 backref_offset; }; static int __clone_root_cmp_bsearch(const void *key, const void *elt) { u64 root = (u64)(uintptr_t)key; const struct clone_root *cr = elt; if (root < cr->root->root_key.objectid) return -1; if (root > cr->root->root_key.objectid) return 1; return 0; } static int __clone_root_cmp_sort(const void *e1, const void *e2) { const struct clone_root *cr1 = e1; const struct clone_root *cr2 = e2; if (cr1->root->root_key.objectid < cr2->root->root_key.objectid) return -1; if (cr1->root->root_key.objectid > cr2->root->root_key.objectid) return 1; return 0; } /* * Called for every backref that is found for the current extent. * Results are collected in sctx->clone_roots->ino/offset. */ static int iterate_backrefs(u64 ino, u64 offset, u64 num_bytes, u64 root_id, void *ctx_) { struct backref_ctx *bctx = ctx_; struct clone_root *clone_root; /* First check if the root is in the list of accepted clone sources */ clone_root = bsearch((void *)(uintptr_t)root_id, bctx->sctx->clone_roots, bctx->sctx->clone_roots_cnt, sizeof(struct clone_root), __clone_root_cmp_bsearch); if (!clone_root) return 0; /* This is our own reference, bail out as we can't clone from it. */ if (clone_root->root == bctx->sctx->send_root && ino == bctx->cur_objectid && offset == bctx->cur_offset) return 0; /* * Make sure we don't consider clones from send_root that are * behind the current inode/offset. */ if (clone_root->root == bctx->sctx->send_root) { /* * If the source inode was not yet processed we can't issue a * clone operation, as the source extent does not exist yet at * the destination of the stream. */ if (ino > bctx->cur_objectid) return 0; /* * We clone from the inode currently being sent as long as the * source extent is already processed, otherwise we could try * to clone from an extent that does not exist yet at the * destination of the stream. */ if (ino == bctx->cur_objectid && offset + bctx->extent_len > bctx->sctx->cur_inode_next_write_offset) return 0; } bctx->found++; clone_root->found_ref = true; /* * If the given backref refers to a file extent item with a larger * number of bytes than what we found before, use the new one so that * we clone more optimally and end up doing less writes and getting * less exclusive, non-shared extents at the destination. */ if (num_bytes > clone_root->num_bytes) { clone_root->ino = ino; clone_root->offset = offset; clone_root->num_bytes = num_bytes; /* * Found a perfect candidate, so there's no need to continue * backref walking. */ if (num_bytes >= bctx->extent_len) return BTRFS_ITERATE_EXTENT_INODES_STOP; } return 0; } static bool lookup_backref_cache(u64 leaf_bytenr, void *ctx, const u64 **root_ids_ret, int *root_count_ret) { struct backref_ctx *bctx = ctx; struct send_ctx *sctx = bctx->sctx; struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; const u64 key = leaf_bytenr >> fs_info->sectorsize_bits; struct btrfs_lru_cache_entry *raw_entry; struct backref_cache_entry *entry; if (btrfs_lru_cache_size(&sctx->backref_cache) == 0) return false; /* * If relocation happened since we first filled the cache, then we must * empty the cache and can not use it, because even though we operate on * read-only roots, their leaves and nodes may have been reallocated and * now be used for different nodes/leaves of the same tree or some other * tree. * * We are called from iterate_extent_inodes() while either holding a * transaction handle or holding fs_info->commit_root_sem, so no need * to take any lock here. */ if (fs_info->last_reloc_trans > sctx->backref_cache_last_reloc_trans) { btrfs_lru_cache_clear(&sctx->backref_cache); return false; } raw_entry = btrfs_lru_cache_lookup(&sctx->backref_cache, key, 0); if (!raw_entry) return false; entry = container_of(raw_entry, struct backref_cache_entry, entry); *root_ids_ret = entry->root_ids; *root_count_ret = entry->num_roots; return true; } static void store_backref_cache(u64 leaf_bytenr, const struct ulist *root_ids, void *ctx) { struct backref_ctx *bctx = ctx; struct send_ctx *sctx = bctx->sctx; struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; struct backref_cache_entry *new_entry; struct ulist_iterator uiter; struct ulist_node *node; int ret; /* * We're called while holding a transaction handle or while holding * fs_info->commit_root_sem (at iterate_extent_inodes()), so must do a * NOFS allocation. */ new_entry = kmalloc(sizeof(struct backref_cache_entry), GFP_NOFS); /* No worries, cache is optional. */ if (!new_entry) return; new_entry->entry.key = leaf_bytenr >> fs_info->sectorsize_bits; new_entry->entry.gen = 0; new_entry->num_roots = 0; ULIST_ITER_INIT(&uiter); while ((node = ulist_next(root_ids, &uiter)) != NULL) { const u64 root_id = node->val; struct clone_root *root; root = bsearch((void *)(uintptr_t)root_id, sctx->clone_roots, sctx->clone_roots_cnt, sizeof(struct clone_root), __clone_root_cmp_bsearch); if (!root) continue; /* Too many roots, just exit, no worries as caching is optional. */ if (new_entry->num_roots >= SEND_MAX_BACKREF_CACHE_ROOTS) { kfree(new_entry); return; } new_entry->root_ids[new_entry->num_roots] = root_id; new_entry->num_roots++; } /* * We may have not added any roots to the new cache entry, which means * none of the roots is part of the list of roots from which we are * allowed to clone. Cache the new entry as it's still useful to avoid * backref walking to determine which roots have a path to the leaf. * * Also use GFP_NOFS because we're called while holding a transaction * handle or while holding fs_info->commit_root_sem. */ ret = btrfs_lru_cache_store(&sctx->backref_cache, &new_entry->entry, GFP_NOFS); ASSERT(ret == 0 || ret == -ENOMEM); if (ret) { /* Caching is optional, no worries. */ kfree(new_entry); return; } /* * We are called from iterate_extent_inodes() while either holding a * transaction handle or holding fs_info->commit_root_sem, so no need * to take any lock here. */ if (btrfs_lru_cache_size(&sctx->backref_cache) == 1) sctx->backref_cache_last_reloc_trans = fs_info->last_reloc_trans; } static int check_extent_item(u64 bytenr, const struct btrfs_extent_item *ei, const struct extent_buffer *leaf, void *ctx) { const u64 refs = btrfs_extent_refs(leaf, ei); const struct backref_ctx *bctx = ctx; const struct send_ctx *sctx = bctx->sctx; if (bytenr == bctx->bytenr) { const u64 flags = btrfs_extent_flags(leaf, ei); if (WARN_ON(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) return -EUCLEAN; /* * If we have only one reference and only the send root as a * clone source - meaning no clone roots were given in the * struct btrfs_ioctl_send_args passed to the send ioctl - then * it's our reference and there's no point in doing backref * walking which is expensive, so exit early. */ if (refs == 1 && sctx->clone_roots_cnt == 1) return -ENOENT; } /* * Backreference walking (iterate_extent_inodes() below) is currently * too expensive when an extent has a large number of references, both * in time spent and used memory. So for now just fallback to write * operations instead of clone operations when an extent has more than * a certain amount of references. */ if (refs > SEND_MAX_EXTENT_REFS) return -ENOENT; return 0; } static bool skip_self_data_ref(u64 root, u64 ino, u64 offset, void *ctx) { const struct backref_ctx *bctx = ctx; if (ino == bctx->cur_objectid && root == bctx->backref_owner && offset == bctx->backref_offset) return true; return false; } /* * Given an inode, offset and extent item, it finds a good clone for a clone * instruction. Returns -ENOENT when none could be found. The function makes * sure that the returned clone is usable at the point where sending is at the * moment. This means, that no clones are accepted which lie behind the current * inode+offset. * * path must point to the extent item when called. */ static int find_extent_clone(struct send_ctx *sctx, struct btrfs_path *path, u64 ino, u64 data_offset, u64 ino_size, struct clone_root **found) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret; int extent_type; u64 logical; u64 disk_byte; u64 num_bytes; struct btrfs_file_extent_item *fi; struct extent_buffer *eb = path->nodes[0]; struct backref_ctx backref_ctx = { 0 }; struct btrfs_backref_walk_ctx backref_walk_ctx = { 0 }; struct clone_root *cur_clone_root; int compressed; u32 i; /* * With fallocate we can get prealloc extents beyond the inode's i_size, * so we don't do anything here because clone operations can not clone * to a range beyond i_size without increasing the i_size of the * destination inode. */ if (data_offset >= ino_size) return 0; fi = btrfs_item_ptr(eb, path->slots[0], struct btrfs_file_extent_item); extent_type = btrfs_file_extent_type(eb, fi); if (extent_type == BTRFS_FILE_EXTENT_INLINE) return -ENOENT; disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); if (disk_byte == 0) return -ENOENT; compressed = btrfs_file_extent_compression(eb, fi); num_bytes = btrfs_file_extent_num_bytes(eb, fi); logical = disk_byte + btrfs_file_extent_offset(eb, fi); /* * Setup the clone roots. */ for (i = 0; i < sctx->clone_roots_cnt; i++) { cur_clone_root = sctx->clone_roots + i; cur_clone_root->ino = (u64)-1; cur_clone_root->offset = 0; cur_clone_root->num_bytes = 0; cur_clone_root->found_ref = false; } backref_ctx.sctx = sctx; backref_ctx.cur_objectid = ino; backref_ctx.cur_offset = data_offset; backref_ctx.bytenr = disk_byte; /* * Use the header owner and not the send root's id, because in case of a * snapshot we can have shared subtrees. */ backref_ctx.backref_owner = btrfs_header_owner(eb); backref_ctx.backref_offset = data_offset - btrfs_file_extent_offset(eb, fi); /* * The last extent of a file may be too large due to page alignment. * We need to adjust extent_len in this case so that the checks in * iterate_backrefs() work. */ if (data_offset + num_bytes >= ino_size) backref_ctx.extent_len = ino_size - data_offset; else backref_ctx.extent_len = num_bytes; /* * Now collect all backrefs. */ backref_walk_ctx.bytenr = disk_byte; if (compressed == BTRFS_COMPRESS_NONE) backref_walk_ctx.extent_item_pos = btrfs_file_extent_offset(eb, fi); backref_walk_ctx.fs_info = fs_info; backref_walk_ctx.cache_lookup = lookup_backref_cache; backref_walk_ctx.cache_store = store_backref_cache; backref_walk_ctx.indirect_ref_iterator = iterate_backrefs; backref_walk_ctx.check_extent_item = check_extent_item; backref_walk_ctx.user_ctx = &backref_ctx; /* * If have a single clone root, then it's the send root and we can tell * the backref walking code to skip our own backref and not resolve it, * since we can not use it for cloning - the source and destination * ranges can't overlap and in case the leaf is shared through a subtree * due to snapshots, we can't use those other roots since they are not * in the list of clone roots. */ if (sctx->clone_roots_cnt == 1) backref_walk_ctx.skip_data_ref = skip_self_data_ref; ret = iterate_extent_inodes(&backref_walk_ctx, true, iterate_backrefs, &backref_ctx); if (ret < 0) return ret; down_read(&fs_info->commit_root_sem); if (fs_info->last_reloc_trans > sctx->last_reloc_trans) { /* * A transaction commit for a transaction in which block group * relocation was done just happened. * The disk_bytenr of the file extent item we processed is * possibly stale, referring to the extent's location before * relocation. So act as if we haven't found any clone sources * and fallback to write commands, which will read the correct * data from the new extent location. Otherwise we will fail * below because we haven't found our own back reference or we * could be getting incorrect sources in case the old extent * was already reallocated after the relocation. */ up_read(&fs_info->commit_root_sem); return -ENOENT; } up_read(&fs_info->commit_root_sem); btrfs_debug(fs_info, "find_extent_clone: data_offset=%llu, ino=%llu, num_bytes=%llu, logical=%llu", data_offset, ino, num_bytes, logical); if (!backref_ctx.found) { btrfs_debug(fs_info, "no clones found"); return -ENOENT; } cur_clone_root = NULL; for (i = 0; i < sctx->clone_roots_cnt; i++) { struct clone_root *clone_root = &sctx->clone_roots[i]; if (!clone_root->found_ref) continue; /* * Choose the root from which we can clone more bytes, to * minimize write operations and therefore have more extent * sharing at the destination (the same as in the source). */ if (!cur_clone_root || clone_root->num_bytes > cur_clone_root->num_bytes) { cur_clone_root = clone_root; /* * We found an optimal clone candidate (any inode from * any root is fine), so we're done. */ if (clone_root->num_bytes >= backref_ctx.extent_len) break; } } if (cur_clone_root) { *found = cur_clone_root; ret = 0; } else { ret = -ENOENT; } return ret; } static int read_symlink(struct btrfs_root *root, u64 ino, struct fs_path *dest) { int ret; struct btrfs_path *path; struct btrfs_key key; struct btrfs_file_extent_item *ei; u8 type; u8 compression; unsigned long off; int len; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = ino; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; if (ret) { /* * An empty symlink inode. Can happen in rare error paths when * creating a symlink (transaction committed before the inode * eviction handler removed the symlink inode items and a crash * happened in between or the subvol was snapshoted in between). * Print an informative message to dmesg/syslog so that the user * can delete the symlink. */ btrfs_err(root->fs_info, "Found empty symlink inode %llu at root %llu", ino, root->root_key.objectid); ret = -EIO; goto out; } ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_file_extent_item); type = btrfs_file_extent_type(path->nodes[0], ei); if (unlikely(type != BTRFS_FILE_EXTENT_INLINE)) { ret = -EUCLEAN; btrfs_crit(root->fs_info, "send: found symlink extent that is not inline, ino %llu root %llu extent type %d", ino, btrfs_root_id(root), type); goto out; } compression = btrfs_file_extent_compression(path->nodes[0], ei); if (unlikely(compression != BTRFS_COMPRESS_NONE)) { ret = -EUCLEAN; btrfs_crit(root->fs_info, "send: found symlink extent with compression, ino %llu root %llu compression type %d", ino, btrfs_root_id(root), compression); goto out; } off = btrfs_file_extent_inline_start(ei); len = btrfs_file_extent_ram_bytes(path->nodes[0], ei); ret = fs_path_add_from_extent_buffer(dest, path->nodes[0], off, len); out: btrfs_free_path(path); return ret; } /* * Helper function to generate a file name that is unique in the root of * send_root and parent_root. This is used to generate names for orphan inodes. */ static int gen_unique_name(struct send_ctx *sctx, u64 ino, u64 gen, struct fs_path *dest) { int ret = 0; struct btrfs_path *path; struct btrfs_dir_item *di; char tmp[64]; int len; u64 idx = 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; while (1) { struct fscrypt_str tmp_name; len = snprintf(tmp, sizeof(tmp), "o%llu-%llu-%llu", ino, gen, idx); ASSERT(len < sizeof(tmp)); tmp_name.name = tmp; tmp_name.len = strlen(tmp); di = btrfs_lookup_dir_item(NULL, sctx->send_root, path, BTRFS_FIRST_FREE_OBJECTID, &tmp_name, 0); btrfs_release_path(path); if (IS_ERR(di)) { ret = PTR_ERR(di); goto out; } if (di) { /* not unique, try again */ idx++; continue; } if (!sctx->parent_root) { /* unique */ ret = 0; break; } di = btrfs_lookup_dir_item(NULL, sctx->parent_root, path, BTRFS_FIRST_FREE_OBJECTID, &tmp_name, 0); btrfs_release_path(path); if (IS_ERR(di)) { ret = PTR_ERR(di); goto out; } if (di) { /* not unique, try again */ idx++; continue; } /* unique */ break; } ret = fs_path_add(dest, tmp, strlen(tmp)); out: btrfs_free_path(path); return ret; } enum inode_state { inode_state_no_change, inode_state_will_create, inode_state_did_create, inode_state_will_delete, inode_state_did_delete, }; static int get_cur_inode_state(struct send_ctx *sctx, u64 ino, u64 gen, u64 *send_gen, u64 *parent_gen) { int ret; int left_ret; int right_ret; u64 left_gen; u64 right_gen = 0; struct btrfs_inode_info info; ret = get_inode_info(sctx->send_root, ino, &info); if (ret < 0 && ret != -ENOENT) goto out; left_ret = (info.nlink == 0) ? -ENOENT : ret; left_gen = info.gen; if (send_gen) *send_gen = ((left_ret == -ENOENT) ? 0 : info.gen); if (!sctx->parent_root) { right_ret = -ENOENT; } else { ret = get_inode_info(sctx->parent_root, ino, &info); if (ret < 0 && ret != -ENOENT) goto out; right_ret = (info.nlink == 0) ? -ENOENT : ret; right_gen = info.gen; if (parent_gen) *parent_gen = ((right_ret == -ENOENT) ? 0 : info.gen); } if (!left_ret && !right_ret) { if (left_gen == gen && right_gen == gen) { ret = inode_state_no_change; } else if (left_gen == gen) { if (ino < sctx->send_progress) ret = inode_state_did_create; else ret = inode_state_will_create; } else if (right_gen == gen) { if (ino < sctx->send_progress) ret = inode_state_did_delete; else ret = inode_state_will_delete; } else { ret = -ENOENT; } } else if (!left_ret) { if (left_gen == gen) { if (ino < sctx->send_progress) ret = inode_state_did_create; else ret = inode_state_will_create; } else { ret = -ENOENT; } } else if (!right_ret) { if (right_gen == gen) { if (ino < sctx->send_progress) ret = inode_state_did_delete; else ret = inode_state_will_delete; } else { ret = -ENOENT; } } else { ret = -ENOENT; } out: return ret; } static int is_inode_existent(struct send_ctx *sctx, u64 ino, u64 gen, u64 *send_gen, u64 *parent_gen) { int ret; if (ino == BTRFS_FIRST_FREE_OBJECTID) return 1; ret = get_cur_inode_state(sctx, ino, gen, send_gen, parent_gen); if (ret < 0) goto out; if (ret == inode_state_no_change || ret == inode_state_did_create || ret == inode_state_will_delete) ret = 1; else ret = 0; out: return ret; } /* * Helper function to lookup a dir item in a dir. */ static int lookup_dir_item_inode(struct btrfs_root *root, u64 dir, const char *name, int name_len, u64 *found_inode) { int ret = 0; struct btrfs_dir_item *di; struct btrfs_key key; struct btrfs_path *path; struct fscrypt_str name_str = FSTR_INIT((char *)name, name_len); path = alloc_path_for_send(); if (!path) return -ENOMEM; di = btrfs_lookup_dir_item(NULL, root, path, dir, &name_str, 0); if (IS_ERR_OR_NULL(di)) { ret = di ? PTR_ERR(di) : -ENOENT; goto out; } btrfs_dir_item_key_to_cpu(path->nodes[0], di, &key); if (key.type == BTRFS_ROOT_ITEM_KEY) { ret = -ENOENT; goto out; } *found_inode = key.objectid; out: btrfs_free_path(path); return ret; } /* * Looks up the first btrfs_inode_ref of a given ino. It returns the parent dir, * generation of the parent dir and the name of the dir entry. */ static int get_first_ref(struct btrfs_root *root, u64 ino, u64 *dir, u64 *dir_gen, struct fs_path *name) { int ret; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_path *path; int len; u64 parent_dir; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = ino; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; ret = btrfs_search_slot_for_read(root, &key, path, 1, 0); if (ret < 0) goto out; if (!ret) btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]); if (ret || found_key.objectid != ino || (found_key.type != BTRFS_INODE_REF_KEY && found_key.type != BTRFS_INODE_EXTREF_KEY)) { ret = -ENOENT; goto out; } if (found_key.type == BTRFS_INODE_REF_KEY) { struct btrfs_inode_ref *iref; iref = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_inode_ref); len = btrfs_inode_ref_name_len(path->nodes[0], iref); ret = fs_path_add_from_extent_buffer(name, path->nodes[0], (unsigned long)(iref + 1), len); parent_dir = found_key.offset; } else { struct btrfs_inode_extref *extref; extref = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_inode_extref); len = btrfs_inode_extref_name_len(path->nodes[0], extref); ret = fs_path_add_from_extent_buffer(name, path->nodes[0], (unsigned long)&extref->name, len); parent_dir = btrfs_inode_extref_parent(path->nodes[0], extref); } if (ret < 0) goto out; btrfs_release_path(path); if (dir_gen) { ret = get_inode_gen(root, parent_dir, dir_gen); if (ret < 0) goto out; } *dir = parent_dir; out: btrfs_free_path(path); return ret; } static int is_first_ref(struct btrfs_root *root, u64 ino, u64 dir, const char *name, int name_len) { int ret; struct fs_path *tmp_name; u64 tmp_dir; tmp_name = fs_path_alloc(); if (!tmp_name) return -ENOMEM; ret = get_first_ref(root, ino, &tmp_dir, NULL, tmp_name); if (ret < 0) goto out; if (dir != tmp_dir || name_len != fs_path_len(tmp_name)) { ret = 0; goto out; } ret = !memcmp(tmp_name->start, name, name_len); out: fs_path_free(tmp_name); return ret; } /* * Used by process_recorded_refs to determine if a new ref would overwrite an * already existing ref. In case it detects an overwrite, it returns the * inode/gen in who_ino/who_gen. * When an overwrite is detected, process_recorded_refs does proper orphanizing * to make sure later references to the overwritten inode are possible. * Orphanizing is however only required for the first ref of an inode. * process_recorded_refs does an additional is_first_ref check to see if * orphanizing is really required. */ static int will_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen, const char *name, int name_len, u64 *who_ino, u64 *who_gen, u64 *who_mode) { int ret; u64 parent_root_dir_gen; u64 other_inode = 0; struct btrfs_inode_info info; if (!sctx->parent_root) return 0; ret = is_inode_existent(sctx, dir, dir_gen, NULL, &parent_root_dir_gen); if (ret <= 0) return 0; /* * If we have a parent root we need to verify that the parent dir was * not deleted and then re-created, if it was then we have no overwrite * and we can just unlink this entry. * * @parent_root_dir_gen was set to 0 if the inode does not exist in the * parent root. */ if (sctx->parent_root && dir != BTRFS_FIRST_FREE_OBJECTID && parent_root_dir_gen != dir_gen) return 0; ret = lookup_dir_item_inode(sctx->parent_root, dir, name, name_len, &other_inode); if (ret == -ENOENT) return 0; else if (ret < 0) return ret; /* * Check if the overwritten ref was already processed. If yes, the ref * was already unlinked/moved, so we can safely assume that we will not * overwrite anything at this point in time. */ if (other_inode > sctx->send_progress || is_waiting_for_move(sctx, other_inode)) { ret = get_inode_info(sctx->parent_root, other_inode, &info); if (ret < 0) return ret; *who_ino = other_inode; *who_gen = info.gen; *who_mode = info.mode; return 1; } return 0; } /* * Checks if the ref was overwritten by an already processed inode. This is * used by __get_cur_name_and_parent to find out if the ref was orphanized and * thus the orphan name needs be used. * process_recorded_refs also uses it to avoid unlinking of refs that were * overwritten. */ static int did_overwrite_ref(struct send_ctx *sctx, u64 dir, u64 dir_gen, u64 ino, u64 ino_gen, const char *name, int name_len) { int ret; u64 ow_inode; u64 ow_gen = 0; u64 send_root_dir_gen; if (!sctx->parent_root) return 0; ret = is_inode_existent(sctx, dir, dir_gen, &send_root_dir_gen, NULL); if (ret <= 0) return ret; /* * @send_root_dir_gen was set to 0 if the inode does not exist in the * send root. */ if (dir != BTRFS_FIRST_FREE_OBJECTID && send_root_dir_gen != dir_gen) return 0; /* check if the ref was overwritten by another ref */ ret = lookup_dir_item_inode(sctx->send_root, dir, name, name_len, &ow_inode); if (ret == -ENOENT) { /* was never and will never be overwritten */ return 0; } else if (ret < 0) { return ret; } if (ow_inode == ino) { ret = get_inode_gen(sctx->send_root, ow_inode, &ow_gen); if (ret < 0) return ret; /* It's the same inode, so no overwrite happened. */ if (ow_gen == ino_gen) return 0; } /* * We know that it is or will be overwritten. Check this now. * The current inode being processed might have been the one that caused * inode 'ino' to be orphanized, therefore check if ow_inode matches * the current inode being processed. */ if (ow_inode < sctx->send_progress) return 1; if (ino != sctx->cur_ino && ow_inode == sctx->cur_ino) { if (ow_gen == 0) { ret = get_inode_gen(sctx->send_root, ow_inode, &ow_gen); if (ret < 0) return ret; } if (ow_gen == sctx->cur_inode_gen) return 1; } return 0; } /* * Same as did_overwrite_ref, but also checks if it is the first ref of an inode * that got overwritten. This is used by process_recorded_refs to determine * if it has to use the path as returned by get_cur_path or the orphan name. */ static int did_overwrite_first_ref(struct send_ctx *sctx, u64 ino, u64 gen) { int ret = 0; struct fs_path *name = NULL; u64 dir; u64 dir_gen; if (!sctx->parent_root) goto out; name = fs_path_alloc(); if (!name) return -ENOMEM; ret = get_first_ref(sctx->parent_root, ino, &dir, &dir_gen, name); if (ret < 0) goto out; ret = did_overwrite_ref(sctx, dir, dir_gen, ino, gen, name->start, fs_path_len(name)); out: fs_path_free(name); return ret; } static inline struct name_cache_entry *name_cache_search(struct send_ctx *sctx, u64 ino, u64 gen) { struct btrfs_lru_cache_entry *entry; entry = btrfs_lru_cache_lookup(&sctx->name_cache, ino, gen); if (!entry) return NULL; return container_of(entry, struct name_cache_entry, entry); } /* * Used by get_cur_path for each ref up to the root. * Returns 0 if it succeeded. * Returns 1 if the inode is not existent or got overwritten. In that case, the * name is an orphan name. This instructs get_cur_path to stop iterating. If 1 * is returned, parent_ino/parent_gen are not guaranteed to be valid. * Returns <0 in case of error. */ static int __get_cur_name_and_parent(struct send_ctx *sctx, u64 ino, u64 gen, u64 *parent_ino, u64 *parent_gen, struct fs_path *dest) { int ret; int nce_ret; struct name_cache_entry *nce; /* * First check if we already did a call to this function with the same * ino/gen. If yes, check if the cache entry is still up-to-date. If yes * return the cached result. */ nce = name_cache_search(sctx, ino, gen); if (nce) { if (ino < sctx->send_progress && nce->need_later_update) { btrfs_lru_cache_remove(&sctx->name_cache, &nce->entry); nce = NULL; } else { *parent_ino = nce->parent_ino; *parent_gen = nce->parent_gen; ret = fs_path_add(dest, nce->name, nce->name_len); if (ret < 0) goto out; ret = nce->ret; goto out; } } /* * If the inode is not existent yet, add the orphan name and return 1. * This should only happen for the parent dir that we determine in * record_new_ref_if_needed(). */ ret = is_inode_existent(sctx, ino, gen, NULL, NULL); if (ret < 0) goto out; if (!ret) { ret = gen_unique_name(sctx, ino, gen, dest); if (ret < 0) goto out; ret = 1; goto out_cache; } /* * Depending on whether the inode was already processed or not, use * send_root or parent_root for ref lookup. */ if (ino < sctx->send_progress) ret = get_first_ref(sctx->send_root, ino, parent_ino, parent_gen, dest); else ret = get_first_ref(sctx->parent_root, ino, parent_ino, parent_gen, dest); if (ret < 0) goto out; /* * Check if the ref was overwritten by an inode's ref that was processed * earlier. If yes, treat as orphan and return 1. */ ret = did_overwrite_ref(sctx, *parent_ino, *parent_gen, ino, gen, dest->start, dest->end - dest->start); if (ret < 0) goto out; if (ret) { fs_path_reset(dest); ret = gen_unique_name(sctx, ino, gen, dest); if (ret < 0) goto out; ret = 1; } out_cache: /* * Store the result of the lookup in the name cache. */ nce = kmalloc(sizeof(*nce) + fs_path_len(dest) + 1, GFP_KERNEL); if (!nce) { ret = -ENOMEM; goto out; } nce->entry.key = ino; nce->entry.gen = gen; nce->parent_ino = *parent_ino; nce->parent_gen = *parent_gen; nce->name_len = fs_path_len(dest); nce->ret = ret; strcpy(nce->name, dest->start); if (ino < sctx->send_progress) nce->need_later_update = 0; else nce->need_later_update = 1; nce_ret = btrfs_lru_cache_store(&sctx->name_cache, &nce->entry, GFP_KERNEL); if (nce_ret < 0) { kfree(nce); ret = nce_ret; } out: return ret; } /* * Magic happens here. This function returns the first ref to an inode as it * would look like while receiving the stream at this point in time. * We walk the path up to the root. For every inode in between, we check if it * was already processed/sent. If yes, we continue with the parent as found * in send_root. If not, we continue with the parent as found in parent_root. * If we encounter an inode that was deleted at this point in time, we use the * inodes "orphan" name instead of the real name and stop. Same with new inodes * that were not created yet and overwritten inodes/refs. * * When do we have orphan inodes: * 1. When an inode is freshly created and thus no valid refs are available yet * 2. When a directory lost all it's refs (deleted) but still has dir items * inside which were not processed yet (pending for move/delete). If anyone * tried to get the path to the dir items, it would get a path inside that * orphan directory. * 3. When an inode is moved around or gets new links, it may overwrite the ref * of an unprocessed inode. If in that case the first ref would be * overwritten, the overwritten inode gets "orphanized". Later when we * process this overwritten inode, it is restored at a new place by moving * the orphan inode. * * sctx->send_progress tells this function at which point in time receiving * would be. */ static int get_cur_path(struct send_ctx *sctx, u64 ino, u64 gen, struct fs_path *dest) { int ret = 0; struct fs_path *name = NULL; u64 parent_inode = 0; u64 parent_gen = 0; int stop = 0; name = fs_path_alloc(); if (!name) { ret = -ENOMEM; goto out; } dest->reversed = 1; fs_path_reset(dest); while (!stop && ino != BTRFS_FIRST_FREE_OBJECTID) { struct waiting_dir_move *wdm; fs_path_reset(name); if (is_waiting_for_rm(sctx, ino, gen)) { ret = gen_unique_name(sctx, ino, gen, name); if (ret < 0) goto out; ret = fs_path_add_path(dest, name); break; } wdm = get_waiting_dir_move(sctx, ino); if (wdm && wdm->orphanized) { ret = gen_unique_name(sctx, ino, gen, name); stop = 1; } else if (wdm) { ret = get_first_ref(sctx->parent_root, ino, &parent_inode, &parent_gen, name); } else { ret = __get_cur_name_and_parent(sctx, ino, gen, &parent_inode, &parent_gen, name); if (ret) stop = 1; } if (ret < 0) goto out; ret = fs_path_add_path(dest, name); if (ret < 0) goto out; ino = parent_inode; gen = parent_gen; } out: fs_path_free(name); if (!ret) fs_path_unreverse(dest); return ret; } /* * Sends a BTRFS_SEND_C_SUBVOL command/item to userspace */ static int send_subvol_begin(struct send_ctx *sctx) { int ret; struct btrfs_root *send_root = sctx->send_root; struct btrfs_root *parent_root = sctx->parent_root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_root_ref *ref; struct extent_buffer *leaf; char *name = NULL; int namelen; path = btrfs_alloc_path(); if (!path) return -ENOMEM; name = kmalloc(BTRFS_PATH_NAME_MAX, GFP_KERNEL); if (!name) { btrfs_free_path(path); return -ENOMEM; } key.objectid = send_root->root_key.objectid; key.type = BTRFS_ROOT_BACKREF_KEY; key.offset = 0; ret = btrfs_search_slot_for_read(send_root->fs_info->tree_root, &key, path, 1, 0); if (ret < 0) goto out; if (ret) { ret = -ENOENT; goto out; } leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); if (key.type != BTRFS_ROOT_BACKREF_KEY || key.objectid != send_root->root_key.objectid) { ret = -ENOENT; goto out; } ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref); namelen = btrfs_root_ref_name_len(leaf, ref); read_extent_buffer(leaf, name, (unsigned long)(ref + 1), namelen); btrfs_release_path(path); if (parent_root) { ret = begin_cmd(sctx, BTRFS_SEND_C_SNAPSHOT); if (ret < 0) goto out; } else { ret = begin_cmd(sctx, BTRFS_SEND_C_SUBVOL); if (ret < 0) goto out; } TLV_PUT_STRING(sctx, BTRFS_SEND_A_PATH, name, namelen); if (!btrfs_is_empty_uuid(sctx->send_root->root_item.received_uuid)) TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID, sctx->send_root->root_item.received_uuid); else TLV_PUT_UUID(sctx, BTRFS_SEND_A_UUID, sctx->send_root->root_item.uuid); TLV_PUT_U64(sctx, BTRFS_SEND_A_CTRANSID, btrfs_root_ctransid(&sctx->send_root->root_item)); if (parent_root) { if (!btrfs_is_empty_uuid(parent_root->root_item.received_uuid)) TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, parent_root->root_item.received_uuid); else TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, parent_root->root_item.uuid); TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID, btrfs_root_ctransid(&sctx->parent_root->root_item)); } ret = send_cmd(sctx); tlv_put_failure: out: btrfs_free_path(path); kfree(name); return ret; } static int send_truncate(struct send_ctx *sctx, u64 ino, u64 gen, u64 size) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; btrfs_debug(fs_info, "send_truncate %llu size=%llu", ino, size); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_TRUNCATE); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, size); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_chmod(struct send_ctx *sctx, u64 ino, u64 gen, u64 mode) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; btrfs_debug(fs_info, "send_chmod %llu mode=%llu", ino, mode); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_CHMOD); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode & 07777); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_fileattr(struct send_ctx *sctx, u64 ino, u64 gen, u64 fileattr) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; if (sctx->proto < 2) return 0; btrfs_debug(fs_info, "send_fileattr %llu fileattr=%llu", ino, fileattr); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_FILEATTR); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILEATTR, fileattr); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_chown(struct send_ctx *sctx, u64 ino, u64 gen, u64 uid, u64 gid) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; btrfs_debug(fs_info, "send_chown %llu uid=%llu, gid=%llu", ino, uid, gid); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_CHOWN); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_UID, uid); TLV_PUT_U64(sctx, BTRFS_SEND_A_GID, gid); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_utimes(struct send_ctx *sctx, u64 ino, u64 gen) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p = NULL; struct btrfs_inode_item *ii; struct btrfs_path *path = NULL; struct extent_buffer *eb; struct btrfs_key key; int slot; btrfs_debug(fs_info, "send_utimes %llu", ino); p = fs_path_alloc(); if (!p) return -ENOMEM; path = alloc_path_for_send(); if (!path) { ret = -ENOMEM; goto out; } key.objectid = ino; key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0); if (ret > 0) ret = -ENOENT; if (ret < 0) goto out; eb = path->nodes[0]; slot = path->slots[0]; ii = btrfs_item_ptr(eb, slot, struct btrfs_inode_item); ret = begin_cmd(sctx, BTRFS_SEND_C_UTIMES); if (ret < 0) goto out; ret = get_cur_path(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_ATIME, eb, &ii->atime); TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_MTIME, eb, &ii->mtime); TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_CTIME, eb, &ii->ctime); if (sctx->proto >= 2) TLV_PUT_BTRFS_TIMESPEC(sctx, BTRFS_SEND_A_OTIME, eb, &ii->otime); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); btrfs_free_path(path); return ret; } /* * If the cache is full, we can't remove entries from it and do a call to * send_utimes() for each respective inode, because we might be finishing * processing an inode that is a directory and it just got renamed, and existing * entries in the cache may refer to inodes that have the directory in their * full path - in which case we would generate outdated paths (pre-rename) * for the inodes that the cache entries point to. Instead of prunning the * cache when inserting, do it after we finish processing each inode at * finish_inode_if_needed(). */ static int cache_dir_utimes(struct send_ctx *sctx, u64 dir, u64 gen) { struct btrfs_lru_cache_entry *entry; int ret; entry = btrfs_lru_cache_lookup(&sctx->dir_utimes_cache, dir, gen); if (entry != NULL) return 0; /* Caching is optional, don't fail if we can't allocate memory. */ entry = kmalloc(sizeof(*entry), GFP_KERNEL); if (!entry) return send_utimes(sctx, dir, gen); entry->key = dir; entry->gen = gen; ret = btrfs_lru_cache_store(&sctx->dir_utimes_cache, entry, GFP_KERNEL); ASSERT(ret != -EEXIST); if (ret) { kfree(entry); return send_utimes(sctx, dir, gen); } return 0; } static int trim_dir_utimes_cache(struct send_ctx *sctx) { while (btrfs_lru_cache_size(&sctx->dir_utimes_cache) > SEND_MAX_DIR_UTIMES_CACHE_SIZE) { struct btrfs_lru_cache_entry *lru; int ret; lru = btrfs_lru_cache_lru_entry(&sctx->dir_utimes_cache); ASSERT(lru != NULL); ret = send_utimes(sctx, lru->key, lru->gen); if (ret) return ret; btrfs_lru_cache_remove(&sctx->dir_utimes_cache, lru); } return 0; } /* * Sends a BTRFS_SEND_C_MKXXX or SYMLINK command to user space. We don't have * a valid path yet because we did not process the refs yet. So, the inode * is created as orphan. */ static int send_create_inode(struct send_ctx *sctx, u64 ino) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; int cmd; struct btrfs_inode_info info; u64 gen; u64 mode; u64 rdev; btrfs_debug(fs_info, "send_create_inode %llu", ino); p = fs_path_alloc(); if (!p) return -ENOMEM; if (ino != sctx->cur_ino) { ret = get_inode_info(sctx->send_root, ino, &info); if (ret < 0) goto out; gen = info.gen; mode = info.mode; rdev = info.rdev; } else { gen = sctx->cur_inode_gen; mode = sctx->cur_inode_mode; rdev = sctx->cur_inode_rdev; } if (S_ISREG(mode)) { cmd = BTRFS_SEND_C_MKFILE; } else if (S_ISDIR(mode)) { cmd = BTRFS_SEND_C_MKDIR; } else if (S_ISLNK(mode)) { cmd = BTRFS_SEND_C_SYMLINK; } else if (S_ISCHR(mode) || S_ISBLK(mode)) { cmd = BTRFS_SEND_C_MKNOD; } else if (S_ISFIFO(mode)) { cmd = BTRFS_SEND_C_MKFIFO; } else if (S_ISSOCK(mode)) { cmd = BTRFS_SEND_C_MKSOCK; } else { btrfs_warn(sctx->send_root->fs_info, "unexpected inode type %o", (int)(mode & S_IFMT)); ret = -EOPNOTSUPP; goto out; } ret = begin_cmd(sctx, cmd); if (ret < 0) goto out; ret = gen_unique_name(sctx, ino, gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_INO, ino); if (S_ISLNK(mode)) { fs_path_reset(p); ret = read_symlink(sctx->send_root, ino, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH_LINK, p); } else if (S_ISCHR(mode) || S_ISBLK(mode) || S_ISFIFO(mode) || S_ISSOCK(mode)) { TLV_PUT_U64(sctx, BTRFS_SEND_A_RDEV, new_encode_dev(rdev)); TLV_PUT_U64(sctx, BTRFS_SEND_A_MODE, mode); } ret = send_cmd(sctx); if (ret < 0) goto out; tlv_put_failure: out: fs_path_free(p); return ret; } static void cache_dir_created(struct send_ctx *sctx, u64 dir) { struct btrfs_lru_cache_entry *entry; int ret; /* Caching is optional, ignore any failures. */ entry = kmalloc(sizeof(*entry), GFP_KERNEL); if (!entry) return; entry->key = dir; entry->gen = 0; ret = btrfs_lru_cache_store(&sctx->dir_created_cache, entry, GFP_KERNEL); if (ret < 0) kfree(entry); } /* * We need some special handling for inodes that get processed before the parent * directory got created. See process_recorded_refs for details. * This function does the check if we already created the dir out of order. */ static int did_create_dir(struct send_ctx *sctx, u64 dir) { int ret = 0; int iter_ret = 0; struct btrfs_path *path = NULL; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_key di_key; struct btrfs_dir_item *di; if (btrfs_lru_cache_lookup(&sctx->dir_created_cache, dir, 0)) return 1; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = dir; key.type = BTRFS_DIR_INDEX_KEY; key.offset = 0; btrfs_for_each_slot(sctx->send_root, &key, &found_key, path, iter_ret) { struct extent_buffer *eb = path->nodes[0]; if (found_key.objectid != key.objectid || found_key.type != key.type) { ret = 0; break; } di = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dir_item); btrfs_dir_item_key_to_cpu(eb, di, &di_key); if (di_key.type != BTRFS_ROOT_ITEM_KEY && di_key.objectid < sctx->send_progress) { ret = 1; cache_dir_created(sctx, dir); break; } } /* Catch error found during iteration */ if (iter_ret < 0) ret = iter_ret; btrfs_free_path(path); return ret; } /* * Only creates the inode if it is: * 1. Not a directory * 2. Or a directory which was not created already due to out of order * directories. See did_create_dir and process_recorded_refs for details. */ static int send_create_inode_if_needed(struct send_ctx *sctx) { int ret; if (S_ISDIR(sctx->cur_inode_mode)) { ret = did_create_dir(sctx, sctx->cur_ino); if (ret < 0) return ret; else if (ret > 0) return 0; } ret = send_create_inode(sctx, sctx->cur_ino); if (ret == 0 && S_ISDIR(sctx->cur_inode_mode)) cache_dir_created(sctx, sctx->cur_ino); return ret; } struct recorded_ref { struct list_head list; char *name; struct fs_path *full_path; u64 dir; u64 dir_gen; int name_len; struct rb_node node; struct rb_root *root; }; static struct recorded_ref *recorded_ref_alloc(void) { struct recorded_ref *ref; ref = kzalloc(sizeof(*ref), GFP_KERNEL); if (!ref) return NULL; RB_CLEAR_NODE(&ref->node); INIT_LIST_HEAD(&ref->list); return ref; } static void recorded_ref_free(struct recorded_ref *ref) { if (!ref) return; if (!RB_EMPTY_NODE(&ref->node)) rb_erase(&ref->node, ref->root); list_del(&ref->list); fs_path_free(ref->full_path); kfree(ref); } static void set_ref_path(struct recorded_ref *ref, struct fs_path *path) { ref->full_path = path; ref->name = (char *)kbasename(ref->full_path->start); ref->name_len = ref->full_path->end - ref->name; } static int dup_ref(struct recorded_ref *ref, struct list_head *list) { struct recorded_ref *new; new = recorded_ref_alloc(); if (!new) return -ENOMEM; new->dir = ref->dir; new->dir_gen = ref->dir_gen; list_add_tail(&new->list, list); return 0; } static void __free_recorded_refs(struct list_head *head) { struct recorded_ref *cur; while (!list_empty(head)) { cur = list_entry(head->next, struct recorded_ref, list); recorded_ref_free(cur); } } static void free_recorded_refs(struct send_ctx *sctx) { __free_recorded_refs(&sctx->new_refs); __free_recorded_refs(&sctx->deleted_refs); } /* * Renames/moves a file/dir to its orphan name. Used when the first * ref of an unprocessed inode gets overwritten and for all non empty * directories. */ static int orphanize_inode(struct send_ctx *sctx, u64 ino, u64 gen, struct fs_path *path) { int ret; struct fs_path *orphan; orphan = fs_path_alloc(); if (!orphan) return -ENOMEM; ret = gen_unique_name(sctx, ino, gen, orphan); if (ret < 0) goto out; ret = send_rename(sctx, path, orphan); out: fs_path_free(orphan); return ret; } static struct orphan_dir_info *add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino, u64 dir_gen) { struct rb_node **p = &sctx->orphan_dirs.rb_node; struct rb_node *parent = NULL; struct orphan_dir_info *entry, *odi; while (*p) { parent = *p; entry = rb_entry(parent, struct orphan_dir_info, node); if (dir_ino < entry->ino) p = &(*p)->rb_left; else if (dir_ino > entry->ino) p = &(*p)->rb_right; else if (dir_gen < entry->gen) p = &(*p)->rb_left; else if (dir_gen > entry->gen) p = &(*p)->rb_right; else return entry; } odi = kmalloc(sizeof(*odi), GFP_KERNEL); if (!odi) return ERR_PTR(-ENOMEM); odi->ino = dir_ino; odi->gen = dir_gen; odi->last_dir_index_offset = 0; odi->dir_high_seq_ino = 0; rb_link_node(&odi->node, parent, p); rb_insert_color(&odi->node, &sctx->orphan_dirs); return odi; } static struct orphan_dir_info *get_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino, u64 gen) { struct rb_node *n = sctx->orphan_dirs.rb_node; struct orphan_dir_info *entry; while (n) { entry = rb_entry(n, struct orphan_dir_info, node); if (dir_ino < entry->ino) n = n->rb_left; else if (dir_ino > entry->ino) n = n->rb_right; else if (gen < entry->gen) n = n->rb_left; else if (gen > entry->gen) n = n->rb_right; else return entry; } return NULL; } static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen) { struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino, gen); return odi != NULL; } static void free_orphan_dir_info(struct send_ctx *sctx, struct orphan_dir_info *odi) { if (!odi) return; rb_erase(&odi->node, &sctx->orphan_dirs); kfree(odi); } /* * Returns 1 if a directory can be removed at this point in time. * We check this by iterating all dir items and checking if the inode behind * the dir item was already processed. */ static int can_rmdir(struct send_ctx *sctx, u64 dir, u64 dir_gen) { int ret = 0; int iter_ret = 0; struct btrfs_root *root = sctx->parent_root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key found_key; struct btrfs_key loc; struct btrfs_dir_item *di; struct orphan_dir_info *odi = NULL; u64 dir_high_seq_ino = 0; u64 last_dir_index_offset = 0; /* * Don't try to rmdir the top/root subvolume dir. */ if (dir == BTRFS_FIRST_FREE_OBJECTID) return 0; odi = get_orphan_dir_info(sctx, dir, dir_gen); if (odi && sctx->cur_ino < odi->dir_high_seq_ino) return 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; if (!odi) { /* * Find the inode number associated with the last dir index * entry. This is very likely the inode with the highest number * of all inodes that have an entry in the directory. We can * then use it to avoid future calls to can_rmdir(), when * processing inodes with a lower number, from having to search * the parent root b+tree for dir index keys. */ key.objectid = dir; key.type = BTRFS_DIR_INDEX_KEY; key.offset = (u64)-1; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) { goto out; } else if (ret > 0) { /* Can't happen, the root is never empty. */ ASSERT(path->slots[0] > 0); if (WARN_ON(path->slots[0] == 0)) { ret = -EUCLEAN; goto out; } path->slots[0]--; } btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.objectid != dir || key.type != BTRFS_DIR_INDEX_KEY) { /* No index keys, dir can be removed. */ ret = 1; goto out; } di = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_dir_item); btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc); dir_high_seq_ino = loc.objectid; if (sctx->cur_ino < dir_high_seq_ino) { ret = 0; goto out; } btrfs_release_path(path); } key.objectid = dir; key.type = BTRFS_DIR_INDEX_KEY; key.offset = (odi ? odi->last_dir_index_offset : 0); btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { struct waiting_dir_move *dm; if (found_key.objectid != key.objectid || found_key.type != key.type) break; di = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_dir_item); btrfs_dir_item_key_to_cpu(path->nodes[0], di, &loc); dir_high_seq_ino = max(dir_high_seq_ino, loc.objectid); last_dir_index_offset = found_key.offset; dm = get_waiting_dir_move(sctx, loc.objectid); if (dm) { dm->rmdir_ino = dir; dm->rmdir_gen = dir_gen; ret = 0; goto out; } if (loc.objectid > sctx->cur_ino) { ret = 0; goto out; } } if (iter_ret < 0) { ret = iter_ret; goto out; } free_orphan_dir_info(sctx, odi); ret = 1; out: btrfs_free_path(path); if (ret) return ret; if (!odi) { odi = add_orphan_dir_info(sctx, dir, dir_gen); if (IS_ERR(odi)) return PTR_ERR(odi); odi->gen = dir_gen; } odi->last_dir_index_offset = last_dir_index_offset; odi->dir_high_seq_ino = max(odi->dir_high_seq_ino, dir_high_seq_ino); return 0; } static int is_waiting_for_move(struct send_ctx *sctx, u64 ino) { struct waiting_dir_move *entry = get_waiting_dir_move(sctx, ino); return entry != NULL; } static int add_waiting_dir_move(struct send_ctx *sctx, u64 ino, bool orphanized) { struct rb_node **p = &sctx->waiting_dir_moves.rb_node; struct rb_node *parent = NULL; struct waiting_dir_move *entry, *dm; dm = kmalloc(sizeof(*dm), GFP_KERNEL); if (!dm) return -ENOMEM; dm->ino = ino; dm->rmdir_ino = 0; dm->rmdir_gen = 0; dm->orphanized = orphanized; while (*p) { parent = *p; entry = rb_entry(parent, struct waiting_dir_move, node); if (ino < entry->ino) { p = &(*p)->rb_left; } else if (ino > entry->ino) { p = &(*p)->rb_right; } else { kfree(dm); return -EEXIST; } } rb_link_node(&dm->node, parent, p); rb_insert_color(&dm->node, &sctx->waiting_dir_moves); return 0; } static struct waiting_dir_move * get_waiting_dir_move(struct send_ctx *sctx, u64 ino) { struct rb_node *n = sctx->waiting_dir_moves.rb_node; struct waiting_dir_move *entry; while (n) { entry = rb_entry(n, struct waiting_dir_move, node); if (ino < entry->ino) n = n->rb_left; else if (ino > entry->ino) n = n->rb_right; else return entry; } return NULL; } static void free_waiting_dir_move(struct send_ctx *sctx, struct waiting_dir_move *dm) { if (!dm) return; rb_erase(&dm->node, &sctx->waiting_dir_moves); kfree(dm); } static int add_pending_dir_move(struct send_ctx *sctx, u64 ino, u64 ino_gen, u64 parent_ino, struct list_head *new_refs, struct list_head *deleted_refs, const bool is_orphan) { struct rb_node **p = &sctx->pending_dir_moves.rb_node; struct rb_node *parent = NULL; struct pending_dir_move *entry = NULL, *pm; struct recorded_ref *cur; int exists = 0; int ret; pm = kmalloc(sizeof(*pm), GFP_KERNEL); if (!pm) return -ENOMEM; pm->parent_ino = parent_ino; pm->ino = ino; pm->gen = ino_gen; INIT_LIST_HEAD(&pm->list); INIT_LIST_HEAD(&pm->update_refs); RB_CLEAR_NODE(&pm->node); while (*p) { parent = *p; entry = rb_entry(parent, struct pending_dir_move, node); if (parent_ino < entry->parent_ino) { p = &(*p)->rb_left; } else if (parent_ino > entry->parent_ino) { p = &(*p)->rb_right; } else { exists = 1; break; } } list_for_each_entry(cur, deleted_refs, list) { ret = dup_ref(cur, &pm->update_refs); if (ret < 0) goto out; } list_for_each_entry(cur, new_refs, list) { ret = dup_ref(cur, &pm->update_refs); if (ret < 0) goto out; } ret = add_waiting_dir_move(sctx, pm->ino, is_orphan); if (ret) goto out; if (exists) { list_add_tail(&pm->list, &entry->list); } else { rb_link_node(&pm->node, parent, p); rb_insert_color(&pm->node, &sctx->pending_dir_moves); } ret = 0; out: if (ret) { __free_recorded_refs(&pm->update_refs); kfree(pm); } return ret; } static struct pending_dir_move *get_pending_dir_moves(struct send_ctx *sctx, u64 parent_ino) { struct rb_node *n = sctx->pending_dir_moves.rb_node; struct pending_dir_move *entry; while (n) { entry = rb_entry(n, struct pending_dir_move, node); if (parent_ino < entry->parent_ino) n = n->rb_left; else if (parent_ino > entry->parent_ino) n = n->rb_right; else return entry; } return NULL; } static int path_loop(struct send_ctx *sctx, struct fs_path *name, u64 ino, u64 gen, u64 *ancestor_ino) { int ret = 0; u64 parent_inode = 0; u64 parent_gen = 0; u64 start_ino = ino; *ancestor_ino = 0; while (ino != BTRFS_FIRST_FREE_OBJECTID) { fs_path_reset(name); if (is_waiting_for_rm(sctx, ino, gen)) break; if (is_waiting_for_move(sctx, ino)) { if (*ancestor_ino == 0) *ancestor_ino = ino; ret = get_first_ref(sctx->parent_root, ino, &parent_inode, &parent_gen, name); } else { ret = __get_cur_name_and_parent(sctx, ino, gen, &parent_inode, &parent_gen, name); if (ret > 0) { ret = 0; break; } } if (ret < 0) break; if (parent_inode == start_ino) { ret = 1; if (*ancestor_ino == 0) *ancestor_ino = ino; break; } ino = parent_inode; gen = parent_gen; } return ret; } static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm) { struct fs_path *from_path = NULL; struct fs_path *to_path = NULL; struct fs_path *name = NULL; u64 orig_progress = sctx->send_progress; struct recorded_ref *cur; u64 parent_ino, parent_gen; struct waiting_dir_move *dm = NULL; u64 rmdir_ino = 0; u64 rmdir_gen; u64 ancestor; bool is_orphan; int ret; name = fs_path_alloc(); from_path = fs_path_alloc(); if (!name || !from_path) { ret = -ENOMEM; goto out; } dm = get_waiting_dir_move(sctx, pm->ino); ASSERT(dm); rmdir_ino = dm->rmdir_ino; rmdir_gen = dm->rmdir_gen; is_orphan = dm->orphanized; free_waiting_dir_move(sctx, dm); if (is_orphan) { ret = gen_unique_name(sctx, pm->ino, pm->gen, from_path); } else { ret = get_first_ref(sctx->parent_root, pm->ino, &parent_ino, &parent_gen, name); if (ret < 0) goto out; ret = get_cur_path(sctx, parent_ino, parent_gen, from_path); if (ret < 0) goto out; ret = fs_path_add_path(from_path, name); } if (ret < 0) goto out; sctx->send_progress = sctx->cur_ino + 1; ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor); if (ret < 0) goto out; if (ret) { LIST_HEAD(deleted_refs); ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID); ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor, &pm->update_refs, &deleted_refs, is_orphan); if (ret < 0) goto out; if (rmdir_ino) { dm = get_waiting_dir_move(sctx, pm->ino); ASSERT(dm); dm->rmdir_ino = rmdir_ino; dm->rmdir_gen = rmdir_gen; } goto out; } fs_path_reset(name); to_path = name; name = NULL; ret = get_cur_path(sctx, pm->ino, pm->gen, to_path); if (ret < 0) goto out; ret = send_rename(sctx, from_path, to_path); if (ret < 0) goto out; if (rmdir_ino) { struct orphan_dir_info *odi; u64 gen; odi = get_orphan_dir_info(sctx, rmdir_ino, rmdir_gen); if (!odi) { /* already deleted */ goto finish; } gen = odi->gen; ret = can_rmdir(sctx, rmdir_ino, gen); if (ret < 0) goto out; if (!ret) goto finish; name = fs_path_alloc(); if (!name) { ret = -ENOMEM; goto out; } ret = get_cur_path(sctx, rmdir_ino, gen, name); if (ret < 0) goto out; ret = send_rmdir(sctx, name); if (ret < 0) goto out; } finish: ret = cache_dir_utimes(sctx, pm->ino, pm->gen); if (ret < 0) goto out; /* * After rename/move, need to update the utimes of both new parent(s) * and old parent(s). */ list_for_each_entry(cur, &pm->update_refs, list) { /* * The parent inode might have been deleted in the send snapshot */ ret = get_inode_info(sctx->send_root, cur->dir, NULL); if (ret == -ENOENT) { ret = 0; continue; } if (ret < 0) goto out; ret = cache_dir_utimes(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; } out: fs_path_free(name); fs_path_free(from_path); fs_path_free(to_path); sctx->send_progress = orig_progress; return ret; } static void free_pending_move(struct send_ctx *sctx, struct pending_dir_move *m) { if (!list_empty(&m->list)) list_del(&m->list); if (!RB_EMPTY_NODE(&m->node)) rb_erase(&m->node, &sctx->pending_dir_moves); __free_recorded_refs(&m->update_refs); kfree(m); } static void tail_append_pending_moves(struct send_ctx *sctx, struct pending_dir_move *moves, struct list_head *stack) { if (list_empty(&moves->list)) { list_add_tail(&moves->list, stack); } else { LIST_HEAD(list); list_splice_init(&moves->list, &list); list_add_tail(&moves->list, stack); list_splice_tail(&list, stack); } if (!RB_EMPTY_NODE(&moves->node)) { rb_erase(&moves->node, &sctx->pending_dir_moves); RB_CLEAR_NODE(&moves->node); } } static int apply_children_dir_moves(struct send_ctx *sctx) { struct pending_dir_move *pm; LIST_HEAD(stack); u64 parent_ino = sctx->cur_ino; int ret = 0; pm = get_pending_dir_moves(sctx, parent_ino); if (!pm) return 0; tail_append_pending_moves(sctx, pm, &stack); while (!list_empty(&stack)) { pm = list_first_entry(&stack, struct pending_dir_move, list); parent_ino = pm->ino; ret = apply_dir_move(sctx, pm); free_pending_move(sctx, pm); if (ret) goto out; pm = get_pending_dir_moves(sctx, parent_ino); if (pm) tail_append_pending_moves(sctx, pm, &stack); } return 0; out: while (!list_empty(&stack)) { pm = list_first_entry(&stack, struct pending_dir_move, list); free_pending_move(sctx, pm); } return ret; } /* * We might need to delay a directory rename even when no ancestor directory * (in the send root) with a higher inode number than ours (sctx->cur_ino) was * renamed. This happens when we rename a directory to the old name (the name * in the parent root) of some other unrelated directory that got its rename * delayed due to some ancestor with higher number that got renamed. * * Example: * * Parent snapshot: * . (ino 256) * |---- a/ (ino 257) * | |---- file (ino 260) * | * |---- b/ (ino 258) * |---- c/ (ino 259) * * Send snapshot: * . (ino 256) * |---- a/ (ino 258) * |---- x/ (ino 259) * |---- y/ (ino 257) * |----- file (ino 260) * * Here we can not rename 258 from 'b' to 'a' without the rename of inode 257 * from 'a' to 'x/y' happening first, which in turn depends on the rename of * inode 259 from 'c' to 'x'. So the order of rename commands the send stream * must issue is: * * 1 - rename 259 from 'c' to 'x' * 2 - rename 257 from 'a' to 'x/y' * 3 - rename 258 from 'b' to 'a' * * Returns 1 if the rename of sctx->cur_ino needs to be delayed, 0 if it can * be done right away and < 0 on error. */ static int wait_for_dest_dir_move(struct send_ctx *sctx, struct recorded_ref *parent_ref, const bool is_orphan) { struct btrfs_fs_info *fs_info = sctx->parent_root->fs_info; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key di_key; struct btrfs_dir_item *di; u64 left_gen; u64 right_gen; int ret = 0; struct waiting_dir_move *wdm; if (RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) return 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = parent_ref->dir; key.type = BTRFS_DIR_ITEM_KEY; key.offset = btrfs_name_hash(parent_ref->name, parent_ref->name_len); ret = btrfs_search_slot(NULL, sctx->parent_root, &key, path, 0, 0); if (ret < 0) { goto out; } else if (ret > 0) { ret = 0; goto out; } di = btrfs_match_dir_item_name(fs_info, path, parent_ref->name, parent_ref->name_len); if (!di) { ret = 0; goto out; } /* * di_key.objectid has the number of the inode that has a dentry in the * parent directory with the same name that sctx->cur_ino is being * renamed to. We need to check if that inode is in the send root as * well and if it is currently marked as an inode with a pending rename, * if it is, we need to delay the rename of sctx->cur_ino as well, so * that it happens after that other inode is renamed. */ btrfs_dir_item_key_to_cpu(path->nodes[0], di, &di_key); if (di_key.type != BTRFS_INODE_ITEM_KEY) { ret = 0; goto out; } ret = get_inode_gen(sctx->parent_root, di_key.objectid, &left_gen); if (ret < 0) goto out; ret = get_inode_gen(sctx->send_root, di_key.objectid, &right_gen); if (ret < 0) { if (ret == -ENOENT) ret = 0; goto out; } /* Different inode, no need to delay the rename of sctx->cur_ino */ if (right_gen != left_gen) { ret = 0; goto out; } wdm = get_waiting_dir_move(sctx, di_key.objectid); if (wdm && !wdm->orphanized) { ret = add_pending_dir_move(sctx, sctx->cur_ino, sctx->cur_inode_gen, di_key.objectid, &sctx->new_refs, &sctx->deleted_refs, is_orphan); if (!ret) ret = 1; } out: btrfs_free_path(path); return ret; } /* * Check if inode ino2, or any of its ancestors, is inode ino1. * Return 1 if true, 0 if false and < 0 on error. */ static int check_ino_in_path(struct btrfs_root *root, const u64 ino1, const u64 ino1_gen, const u64 ino2, const u64 ino2_gen, struct fs_path *fs_path) { u64 ino = ino2; if (ino1 == ino2) return ino1_gen == ino2_gen; while (ino > BTRFS_FIRST_FREE_OBJECTID) { u64 parent; u64 parent_gen; int ret; fs_path_reset(fs_path); ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path); if (ret < 0) return ret; if (parent == ino1) return parent_gen == ino1_gen; ino = parent; } return 0; } /* * Check if inode ino1 is an ancestor of inode ino2 in the given root for any * possible path (in case ino2 is not a directory and has multiple hard links). * Return 1 if true, 0 if false and < 0 on error. */ static int is_ancestor(struct btrfs_root *root, const u64 ino1, const u64 ino1_gen, const u64 ino2, struct fs_path *fs_path) { bool free_fs_path = false; int ret = 0; int iter_ret = 0; struct btrfs_path *path = NULL; struct btrfs_key key; if (!fs_path) { fs_path = fs_path_alloc(); if (!fs_path) return -ENOMEM; free_fs_path = true; } path = alloc_path_for_send(); if (!path) { ret = -ENOMEM; goto out; } key.objectid = ino2; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; btrfs_for_each_slot(root, &key, &key, path, iter_ret) { struct extent_buffer *leaf = path->nodes[0]; int slot = path->slots[0]; u32 cur_offset = 0; u32 item_size; if (key.objectid != ino2) break; if (key.type != BTRFS_INODE_REF_KEY && key.type != BTRFS_INODE_EXTREF_KEY) break; item_size = btrfs_item_size(leaf, slot); while (cur_offset < item_size) { u64 parent; u64 parent_gen; if (key.type == BTRFS_INODE_EXTREF_KEY) { unsigned long ptr; struct btrfs_inode_extref *extref; ptr = btrfs_item_ptr_offset(leaf, slot); extref = (struct btrfs_inode_extref *) (ptr + cur_offset); parent = btrfs_inode_extref_parent(leaf, extref); cur_offset += sizeof(*extref); cur_offset += btrfs_inode_extref_name_len(leaf, extref); } else { parent = key.offset; cur_offset = item_size; } ret = get_inode_gen(root, parent, &parent_gen); if (ret < 0) goto out; ret = check_ino_in_path(root, ino1, ino1_gen, parent, parent_gen, fs_path); if (ret) goto out; } } ret = 0; if (iter_ret < 0) ret = iter_ret; out: btrfs_free_path(path); if (free_fs_path) fs_path_free(fs_path); return ret; } static int wait_for_parent_move(struct send_ctx *sctx, struct recorded_ref *parent_ref, const bool is_orphan) { int ret = 0; u64 ino = parent_ref->dir; u64 ino_gen = parent_ref->dir_gen; u64 parent_ino_before, parent_ino_after; struct fs_path *path_before = NULL; struct fs_path *path_after = NULL; int len1, len2; path_after = fs_path_alloc(); path_before = fs_path_alloc(); if (!path_after || !path_before) { ret = -ENOMEM; goto out; } /* * Our current directory inode may not yet be renamed/moved because some * ancestor (immediate or not) has to be renamed/moved first. So find if * such ancestor exists and make sure our own rename/move happens after * that ancestor is processed to avoid path build infinite loops (done * at get_cur_path()). */ while (ino > BTRFS_FIRST_FREE_OBJECTID) { u64 parent_ino_after_gen; if (is_waiting_for_move(sctx, ino)) { /* * If the current inode is an ancestor of ino in the * parent root, we need to delay the rename of the * current inode, otherwise don't delayed the rename * because we can end up with a circular dependency * of renames, resulting in some directories never * getting the respective rename operations issued in * the send stream or getting into infinite path build * loops. */ ret = is_ancestor(sctx->parent_root, sctx->cur_ino, sctx->cur_inode_gen, ino, path_before); if (ret) break; } fs_path_reset(path_before); fs_path_reset(path_after); ret = get_first_ref(sctx->send_root, ino, &parent_ino_after, &parent_ino_after_gen, path_after); if (ret < 0) goto out; ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before, NULL, path_before); if (ret < 0 && ret != -ENOENT) { goto out; } else if (ret == -ENOENT) { ret = 0; break; } len1 = fs_path_len(path_before); len2 = fs_path_len(path_after); if (ino > sctx->cur_ino && (parent_ino_before != parent_ino_after || len1 != len2 || memcmp(path_before->start, path_after->start, len1))) { u64 parent_ino_gen; ret = get_inode_gen(sctx->parent_root, ino, &parent_ino_gen); if (ret < 0) goto out; if (ino_gen == parent_ino_gen) { ret = 1; break; } } ino = parent_ino_after; ino_gen = parent_ino_after_gen; } out: fs_path_free(path_before); fs_path_free(path_after); if (ret == 1) { ret = add_pending_dir_move(sctx, sctx->cur_ino, sctx->cur_inode_gen, ino, &sctx->new_refs, &sctx->deleted_refs, is_orphan); if (!ret) ret = 1; } return ret; } static int update_ref_path(struct send_ctx *sctx, struct recorded_ref *ref) { int ret; struct fs_path *new_path; /* * Our reference's name member points to its full_path member string, so * we use here a new path. */ new_path = fs_path_alloc(); if (!new_path) return -ENOMEM; ret = get_cur_path(sctx, ref->dir, ref->dir_gen, new_path); if (ret < 0) { fs_path_free(new_path); return ret; } ret = fs_path_add(new_path, ref->name, ref->name_len); if (ret < 0) { fs_path_free(new_path); return ret; } fs_path_free(ref->full_path); set_ref_path(ref, new_path); return 0; } /* * When processing the new references for an inode we may orphanize an existing * directory inode because its old name conflicts with one of the new references * of the current inode. Later, when processing another new reference of our * inode, we might need to orphanize another inode, but the path we have in the * reference reflects the pre-orphanization name of the directory we previously * orphanized. For example: * * parent snapshot looks like: * * . (ino 256) * |----- f1 (ino 257) * |----- f2 (ino 258) * |----- d1/ (ino 259) * |----- d2/ (ino 260) * * send snapshot looks like: * * . (ino 256) * |----- d1 (ino 258) * |----- f2/ (ino 259) * |----- f2_link/ (ino 260) * | |----- f1 (ino 257) * | * |----- d2 (ino 258) * * When processing inode 257 we compute the name for inode 259 as "d1", and we * cache it in the name cache. Later when we start processing inode 258, when * collecting all its new references we set a full path of "d1/d2" for its new * reference with name "d2". When we start processing the new references we * start by processing the new reference with name "d1", and this results in * orphanizing inode 259, since its old reference causes a conflict. Then we * move on the next new reference, with name "d2", and we find out we must * orphanize inode 260, as its old reference conflicts with ours - but for the * orphanization we use a source path corresponding to the path we stored in the * new reference, which is "d1/d2" and not "o259-6-0/d2" - this makes the * receiver fail since the path component "d1/" no longer exists, it was renamed * to "o259-6-0/" when processing the previous new reference. So in this case we * must recompute the path in the new reference and use it for the new * orphanization operation. */ static int refresh_ref_path(struct send_ctx *sctx, struct recorded_ref *ref) { char *name; int ret; name = kmemdup(ref->name, ref->name_len, GFP_KERNEL); if (!name) return -ENOMEM; fs_path_reset(ref->full_path); ret = get_cur_path(sctx, ref->dir, ref->dir_gen, ref->full_path); if (ret < 0) goto out; ret = fs_path_add(ref->full_path, name, ref->name_len); if (ret < 0) goto out; /* Update the reference's base name pointer. */ set_ref_path(ref, ref->full_path); out: kfree(name); return ret; } /* * This does all the move/link/unlink/rmdir magic. */ static int process_recorded_refs(struct send_ctx *sctx, int *pending_move) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct recorded_ref *cur; struct recorded_ref *cur2; LIST_HEAD(check_dirs); struct fs_path *valid_path = NULL; u64 ow_inode = 0; u64 ow_gen; u64 ow_mode; int did_overwrite = 0; int is_orphan = 0; u64 last_dir_ino_rm = 0; bool can_rename = true; bool orphanized_dir = false; bool orphanized_ancestor = false; btrfs_debug(fs_info, "process_recorded_refs %llu", sctx->cur_ino); /* * This should never happen as the root dir always has the same ref * which is always '..' */ BUG_ON(sctx->cur_ino <= BTRFS_FIRST_FREE_OBJECTID); valid_path = fs_path_alloc(); if (!valid_path) { ret = -ENOMEM; goto out; } /* * First, check if the first ref of the current inode was overwritten * before. If yes, we know that the current inode was already orphanized * and thus use the orphan name. If not, we can use get_cur_path to * get the path of the first ref as it would like while receiving at * this point in time. * New inodes are always orphan at the beginning, so force to use the * orphan name in this case. * The first ref is stored in valid_path and will be updated if it * gets moved around. */ if (!sctx->cur_inode_new) { ret = did_overwrite_first_ref(sctx, sctx->cur_ino, sctx->cur_inode_gen); if (ret < 0) goto out; if (ret) did_overwrite = 1; } if (sctx->cur_inode_new || did_overwrite) { ret = gen_unique_name(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); if (ret < 0) goto out; is_orphan = 1; } else { ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); if (ret < 0) goto out; } /* * Before doing any rename and link operations, do a first pass on the * new references to orphanize any unprocessed inodes that may have a * reference that conflicts with one of the new references of the current * inode. This needs to happen first because a new reference may conflict * with the old reference of a parent directory, so we must make sure * that the path used for link and rename commands don't use an * orphanized name when an ancestor was not yet orphanized. * * Example: * * Parent snapshot: * * . (ino 256) * |----- testdir/ (ino 259) * | |----- a (ino 257) * | * |----- b (ino 258) * * Send snapshot: * * . (ino 256) * |----- testdir_2/ (ino 259) * | |----- a (ino 260) * | * |----- testdir (ino 257) * |----- b (ino 257) * |----- b2 (ino 258) * * Processing the new reference for inode 257 with name "b" may happen * before processing the new reference with name "testdir". If so, we * must make sure that by the time we send a link command to create the * hard link "b", inode 259 was already orphanized, since the generated * path in "valid_path" already contains the orphanized name for 259. * We are processing inode 257, so only later when processing 259 we do * the rename operation to change its temporary (orphanized) name to * "testdir_2". */ list_for_each_entry(cur, &sctx->new_refs, list) { ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen, NULL, NULL); if (ret < 0) goto out; if (ret == inode_state_will_create) continue; /* * Check if this new ref would overwrite the first ref of another * unprocessed inode. If yes, orphanize the overwritten inode. * If we find an overwritten ref that is not the first ref, * simply unlink it. */ ret = will_overwrite_ref(sctx, cur->dir, cur->dir_gen, cur->name, cur->name_len, &ow_inode, &ow_gen, &ow_mode); if (ret < 0) goto out; if (ret) { ret = is_first_ref(sctx->parent_root, ow_inode, cur->dir, cur->name, cur->name_len); if (ret < 0) goto out; if (ret) { struct name_cache_entry *nce; struct waiting_dir_move *wdm; if (orphanized_dir) { ret = refresh_ref_path(sctx, cur); if (ret < 0) goto out; } ret = orphanize_inode(sctx, ow_inode, ow_gen, cur->full_path); if (ret < 0) goto out; if (S_ISDIR(ow_mode)) orphanized_dir = true; /* * If ow_inode has its rename operation delayed * make sure that its orphanized name is used in * the source path when performing its rename * operation. */ wdm = get_waiting_dir_move(sctx, ow_inode); if (wdm) wdm->orphanized = true; /* * Make sure we clear our orphanized inode's * name from the name cache. This is because the * inode ow_inode might be an ancestor of some * other inode that will be orphanized as well * later and has an inode number greater than * sctx->send_progress. We need to prevent * future name lookups from using the old name * and get instead the orphan name. */ nce = name_cache_search(sctx, ow_inode, ow_gen); if (nce) btrfs_lru_cache_remove(&sctx->name_cache, &nce->entry); /* * ow_inode might currently be an ancestor of * cur_ino, therefore compute valid_path (the * current path of cur_ino) again because it * might contain the pre-orphanization name of * ow_inode, which is no longer valid. */ ret = is_ancestor(sctx->parent_root, ow_inode, ow_gen, sctx->cur_ino, NULL); if (ret > 0) { orphanized_ancestor = true; fs_path_reset(valid_path); ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); } if (ret < 0) goto out; } else { /* * If we previously orphanized a directory that * collided with a new reference that we already * processed, recompute the current path because * that directory may be part of the path. */ if (orphanized_dir) { ret = refresh_ref_path(sctx, cur); if (ret < 0) goto out; } ret = send_unlink(sctx, cur->full_path); if (ret < 0) goto out; } } } list_for_each_entry(cur, &sctx->new_refs, list) { /* * We may have refs where the parent directory does not exist * yet. This happens if the parent directories inum is higher * than the current inum. To handle this case, we create the * parent directory out of order. But we need to check if this * did already happen before due to other refs in the same dir. */ ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen, NULL, NULL); if (ret < 0) goto out; if (ret == inode_state_will_create) { ret = 0; /* * First check if any of the current inodes refs did * already create the dir. */ list_for_each_entry(cur2, &sctx->new_refs, list) { if (cur == cur2) break; if (cur2->dir == cur->dir) { ret = 1; break; } } /* * If that did not happen, check if a previous inode * did already create the dir. */ if (!ret) ret = did_create_dir(sctx, cur->dir); if (ret < 0) goto out; if (!ret) { ret = send_create_inode(sctx, cur->dir); if (ret < 0) goto out; cache_dir_created(sctx, cur->dir); } } if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root) { ret = wait_for_dest_dir_move(sctx, cur, is_orphan); if (ret < 0) goto out; if (ret == 1) { can_rename = false; *pending_move = 1; } } if (S_ISDIR(sctx->cur_inode_mode) && sctx->parent_root && can_rename) { ret = wait_for_parent_move(sctx, cur, is_orphan); if (ret < 0) goto out; if (ret == 1) { can_rename = false; *pending_move = 1; } } /* * link/move the ref to the new place. If we have an orphan * inode, move it and update valid_path. If not, link or move * it depending on the inode mode. */ if (is_orphan && can_rename) { ret = send_rename(sctx, valid_path, cur->full_path); if (ret < 0) goto out; is_orphan = 0; ret = fs_path_copy(valid_path, cur->full_path); if (ret < 0) goto out; } else if (can_rename) { if (S_ISDIR(sctx->cur_inode_mode)) { /* * Dirs can't be linked, so move it. For moved * dirs, we always have one new and one deleted * ref. The deleted ref is ignored later. */ ret = send_rename(sctx, valid_path, cur->full_path); if (!ret) ret = fs_path_copy(valid_path, cur->full_path); if (ret < 0) goto out; } else { /* * We might have previously orphanized an inode * which is an ancestor of our current inode, * so our reference's full path, which was * computed before any such orphanizations, must * be updated. */ if (orphanized_dir) { ret = update_ref_path(sctx, cur); if (ret < 0) goto out; } ret = send_link(sctx, cur->full_path, valid_path); if (ret < 0) goto out; } } ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_deleted) { /* * Check if we can already rmdir the directory. If not, * orphanize it. For every dir item inside that gets deleted * later, we do this check again and rmdir it then if possible. * See the use of check_dirs for more details. */ ret = can_rmdir(sctx, sctx->cur_ino, sctx->cur_inode_gen); if (ret < 0) goto out; if (ret) { ret = send_rmdir(sctx, valid_path); if (ret < 0) goto out; } else if (!is_orphan) { ret = orphanize_inode(sctx, sctx->cur_ino, sctx->cur_inode_gen, valid_path); if (ret < 0) goto out; is_orphan = 1; } list_for_each_entry(cur, &sctx->deleted_refs, list) { ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } } else if (S_ISDIR(sctx->cur_inode_mode) && !list_empty(&sctx->deleted_refs)) { /* * We have a moved dir. Add the old parent to check_dirs */ cur = list_entry(sctx->deleted_refs.next, struct recorded_ref, list); ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } else if (!S_ISDIR(sctx->cur_inode_mode)) { /* * We have a non dir inode. Go through all deleted refs and * unlink them if they were not already overwritten by other * inodes. */ list_for_each_entry(cur, &sctx->deleted_refs, list) { ret = did_overwrite_ref(sctx, cur->dir, cur->dir_gen, sctx->cur_ino, sctx->cur_inode_gen, cur->name, cur->name_len); if (ret < 0) goto out; if (!ret) { /* * If we orphanized any ancestor before, we need * to recompute the full path for deleted names, * since any such path was computed before we * processed any references and orphanized any * ancestor inode. */ if (orphanized_ancestor) { ret = update_ref_path(sctx, cur); if (ret < 0) goto out; } ret = send_unlink(sctx, cur->full_path); if (ret < 0) goto out; } ret = dup_ref(cur, &check_dirs); if (ret < 0) goto out; } /* * If the inode is still orphan, unlink the orphan. This may * happen when a previous inode did overwrite the first ref * of this inode and no new refs were added for the current * inode. Unlinking does not mean that the inode is deleted in * all cases. There may still be links to this inode in other * places. */ if (is_orphan) { ret = send_unlink(sctx, valid_path); if (ret < 0) goto out; } } /* * We did collect all parent dirs where cur_inode was once located. We * now go through all these dirs and check if they are pending for * deletion and if it's finally possible to perform the rmdir now. * We also update the inode stats of the parent dirs here. */ list_for_each_entry(cur, &check_dirs, list) { /* * In case we had refs into dirs that were not processed yet, * we don't need to do the utime and rmdir logic for these dirs. * The dir will be processed later. */ if (cur->dir > sctx->cur_ino) continue; ret = get_cur_inode_state(sctx, cur->dir, cur->dir_gen, NULL, NULL); if (ret < 0) goto out; if (ret == inode_state_did_create || ret == inode_state_no_change) { ret = cache_dir_utimes(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; } else if (ret == inode_state_did_delete && cur->dir != last_dir_ino_rm) { ret = can_rmdir(sctx, cur->dir, cur->dir_gen); if (ret < 0) goto out; if (ret) { ret = get_cur_path(sctx, cur->dir, cur->dir_gen, valid_path); if (ret < 0) goto out; ret = send_rmdir(sctx, valid_path); if (ret < 0) goto out; last_dir_ino_rm = cur->dir; } } } ret = 0; out: __free_recorded_refs(&check_dirs); free_recorded_refs(sctx); fs_path_free(valid_path); return ret; } static int rbtree_ref_comp(const void *k, const struct rb_node *node) { const struct recorded_ref *data = k; const struct recorded_ref *ref = rb_entry(node, struct recorded_ref, node); int result; if (data->dir > ref->dir) return 1; if (data->dir < ref->dir) return -1; if (data->dir_gen > ref->dir_gen) return 1; if (data->dir_gen < ref->dir_gen) return -1; if (data->name_len > ref->name_len) return 1; if (data->name_len < ref->name_len) return -1; result = strcmp(data->name, ref->name); if (result > 0) return 1; if (result < 0) return -1; return 0; } static bool rbtree_ref_less(struct rb_node *node, const struct rb_node *parent) { const struct recorded_ref *entry = rb_entry(node, struct recorded_ref, node); return rbtree_ref_comp(entry, parent) < 0; } static int record_ref_in_tree(struct rb_root *root, struct list_head *refs, struct fs_path *name, u64 dir, u64 dir_gen, struct send_ctx *sctx) { int ret = 0; struct fs_path *path = NULL; struct recorded_ref *ref = NULL; path = fs_path_alloc(); if (!path) { ret = -ENOMEM; goto out; } ref = recorded_ref_alloc(); if (!ref) { ret = -ENOMEM; goto out; } ret = get_cur_path(sctx, dir, dir_gen, path); if (ret < 0) goto out; ret = fs_path_add_path(path, name); if (ret < 0) goto out; ref->dir = dir; ref->dir_gen = dir_gen; set_ref_path(ref, path); list_add_tail(&ref->list, refs); rb_add(&ref->node, root, rbtree_ref_less); ref->root = root; out: if (ret) { if (path && (!ref || !ref->full_path)) fs_path_free(path); recorded_ref_free(ref); } return ret; } static int record_new_ref_if_needed(int num, u64 dir, int index, struct fs_path *name, void *ctx) { int ret = 0; struct send_ctx *sctx = ctx; struct rb_node *node = NULL; struct recorded_ref data; struct recorded_ref *ref; u64 dir_gen; ret = get_inode_gen(sctx->send_root, dir, &dir_gen); if (ret < 0) goto out; data.dir = dir; data.dir_gen = dir_gen; set_ref_path(&data, name); node = rb_find(&data, &sctx->rbtree_deleted_refs, rbtree_ref_comp); if (node) { ref = rb_entry(node, struct recorded_ref, node); recorded_ref_free(ref); } else { ret = record_ref_in_tree(&sctx->rbtree_new_refs, &sctx->new_refs, name, dir, dir_gen, sctx); } out: return ret; } static int record_deleted_ref_if_needed(int num, u64 dir, int index, struct fs_path *name, void *ctx) { int ret = 0; struct send_ctx *sctx = ctx; struct rb_node *node = NULL; struct recorded_ref data; struct recorded_ref *ref; u64 dir_gen; ret = get_inode_gen(sctx->parent_root, dir, &dir_gen); if (ret < 0) goto out; data.dir = dir; data.dir_gen = dir_gen; set_ref_path(&data, name); node = rb_find(&data, &sctx->rbtree_new_refs, rbtree_ref_comp); if (node) { ref = rb_entry(node, struct recorded_ref, node); recorded_ref_free(ref); } else { ret = record_ref_in_tree(&sctx->rbtree_deleted_refs, &sctx->deleted_refs, name, dir, dir_gen, sctx); } out: return ret; } static int record_new_ref(struct send_ctx *sctx) { int ret; ret = iterate_inode_ref(sctx->send_root, sctx->left_path, sctx->cmp_key, 0, record_new_ref_if_needed, sctx); if (ret < 0) goto out; ret = 0; out: return ret; } static int record_deleted_ref(struct send_ctx *sctx) { int ret; ret = iterate_inode_ref(sctx->parent_root, sctx->right_path, sctx->cmp_key, 0, record_deleted_ref_if_needed, sctx); if (ret < 0) goto out; ret = 0; out: return ret; } static int record_changed_ref(struct send_ctx *sctx) { int ret = 0; ret = iterate_inode_ref(sctx->send_root, sctx->left_path, sctx->cmp_key, 0, record_new_ref_if_needed, sctx); if (ret < 0) goto out; ret = iterate_inode_ref(sctx->parent_root, sctx->right_path, sctx->cmp_key, 0, record_deleted_ref_if_needed, sctx); if (ret < 0) goto out; ret = 0; out: return ret; } /* * Record and process all refs at once. Needed when an inode changes the * generation number, which means that it was deleted and recreated. */ static int process_all_refs(struct send_ctx *sctx, enum btrfs_compare_tree_result cmd) { int ret = 0; int iter_ret = 0; struct btrfs_root *root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key found_key; iterate_inode_ref_t cb; int pending_move = 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; if (cmd == BTRFS_COMPARE_TREE_NEW) { root = sctx->send_root; cb = record_new_ref_if_needed; } else if (cmd == BTRFS_COMPARE_TREE_DELETED) { root = sctx->parent_root; cb = record_deleted_ref_if_needed; } else { btrfs_err(sctx->send_root->fs_info, "Wrong command %d in process_all_refs", cmd); ret = -EINVAL; goto out; } key.objectid = sctx->cmp_key->objectid; key.type = BTRFS_INODE_REF_KEY; key.offset = 0; btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { if (found_key.objectid != key.objectid || (found_key.type != BTRFS_INODE_REF_KEY && found_key.type != BTRFS_INODE_EXTREF_KEY)) break; ret = iterate_inode_ref(root, path, &found_key, 0, cb, sctx); if (ret < 0) goto out; } /* Catch error found during iteration */ if (iter_ret < 0) { ret = iter_ret; goto out; } btrfs_release_path(path); /* * We don't actually care about pending_move as we are simply * re-creating this inode and will be rename'ing it into place once we * rename the parent directory. */ ret = process_recorded_refs(sctx, &pending_move); out: btrfs_free_path(path); return ret; } static int send_set_xattr(struct send_ctx *sctx, struct fs_path *path, const char *name, int name_len, const char *data, int data_len) { int ret = 0; ret = begin_cmd(sctx, BTRFS_SEND_C_SET_XATTR); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len); TLV_PUT(sctx, BTRFS_SEND_A_XATTR_DATA, data, data_len); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } static int send_remove_xattr(struct send_ctx *sctx, struct fs_path *path, const char *name, int name_len) { int ret = 0; ret = begin_cmd(sctx, BTRFS_SEND_C_REMOVE_XATTR); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); TLV_PUT_STRING(sctx, BTRFS_SEND_A_XATTR_NAME, name, name_len); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } static int __process_new_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, void *ctx) { int ret; struct send_ctx *sctx = ctx; struct fs_path *p; struct posix_acl_xattr_header dummy_acl; /* Capabilities are emitted by finish_inode_if_needed */ if (!strncmp(name, XATTR_NAME_CAPS, name_len)) return 0; p = fs_path_alloc(); if (!p) return -ENOMEM; /* * This hack is needed because empty acls are stored as zero byte * data in xattrs. Problem with that is, that receiving these zero byte * acls will fail later. To fix this, we send a dummy acl list that * only contains the version number and no entries. */ if (!strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS, name_len) || !strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT, name_len)) { if (data_len == 0) { dummy_acl.a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); data = (char *)&dummy_acl; data_len = sizeof(dummy_acl); } } ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; ret = send_set_xattr(sctx, p, name, name_len, data, data_len); out: fs_path_free(p); return ret; } static int __process_deleted_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, void *ctx) { int ret; struct send_ctx *sctx = ctx; struct fs_path *p; p = fs_path_alloc(); if (!p) return -ENOMEM; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; ret = send_remove_xattr(sctx, p, name, name_len); out: fs_path_free(p); return ret; } static int process_new_xattr(struct send_ctx *sctx) { int ret = 0; ret = iterate_dir_item(sctx->send_root, sctx->left_path, __process_new_xattr, sctx); return ret; } static int process_deleted_xattr(struct send_ctx *sctx) { return iterate_dir_item(sctx->parent_root, sctx->right_path, __process_deleted_xattr, sctx); } struct find_xattr_ctx { const char *name; int name_len; int found_idx; char *found_data; int found_data_len; }; static int __find_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, void *vctx) { struct find_xattr_ctx *ctx = vctx; if (name_len == ctx->name_len && strncmp(name, ctx->name, name_len) == 0) { ctx->found_idx = num; ctx->found_data_len = data_len; ctx->found_data = kmemdup(data, data_len, GFP_KERNEL); if (!ctx->found_data) return -ENOMEM; return 1; } return 0; } static int find_xattr(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_key *key, const char *name, int name_len, char **data, int *data_len) { int ret; struct find_xattr_ctx ctx; ctx.name = name; ctx.name_len = name_len; ctx.found_idx = -1; ctx.found_data = NULL; ctx.found_data_len = 0; ret = iterate_dir_item(root, path, __find_xattr, &ctx); if (ret < 0) return ret; if (ctx.found_idx == -1) return -ENOENT; if (data) { *data = ctx.found_data; *data_len = ctx.found_data_len; } else { kfree(ctx.found_data); } return ctx.found_idx; } static int __process_changed_new_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, void *ctx) { int ret; struct send_ctx *sctx = ctx; char *found_data = NULL; int found_data_len = 0; ret = find_xattr(sctx->parent_root, sctx->right_path, sctx->cmp_key, name, name_len, &found_data, &found_data_len); if (ret == -ENOENT) { ret = __process_new_xattr(num, di_key, name, name_len, data, data_len, ctx); } else if (ret >= 0) { if (data_len != found_data_len || memcmp(data, found_data, data_len)) { ret = __process_new_xattr(num, di_key, name, name_len, data, data_len, ctx); } else { ret = 0; } } kfree(found_data); return ret; } static int __process_changed_deleted_xattr(int num, struct btrfs_key *di_key, const char *name, int name_len, const char *data, int data_len, void *ctx) { int ret; struct send_ctx *sctx = ctx; ret = find_xattr(sctx->send_root, sctx->left_path, sctx->cmp_key, name, name_len, NULL, NULL); if (ret == -ENOENT) ret = __process_deleted_xattr(num, di_key, name, name_len, data, data_len, ctx); else if (ret >= 0) ret = 0; return ret; } static int process_changed_xattr(struct send_ctx *sctx) { int ret = 0; ret = iterate_dir_item(sctx->send_root, sctx->left_path, __process_changed_new_xattr, sctx); if (ret < 0) goto out; ret = iterate_dir_item(sctx->parent_root, sctx->right_path, __process_changed_deleted_xattr, sctx); out: return ret; } static int process_all_new_xattrs(struct send_ctx *sctx) { int ret = 0; int iter_ret = 0; struct btrfs_root *root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key found_key; path = alloc_path_for_send(); if (!path) return -ENOMEM; root = sctx->send_root; key.objectid = sctx->cmp_key->objectid; key.type = BTRFS_XATTR_ITEM_KEY; key.offset = 0; btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { if (found_key.objectid != key.objectid || found_key.type != key.type) { ret = 0; break; } ret = iterate_dir_item(root, path, __process_new_xattr, sctx); if (ret < 0) break; } /* Catch error found during iteration */ if (iter_ret < 0) ret = iter_ret; btrfs_free_path(path); return ret; } static int send_verity(struct send_ctx *sctx, struct fs_path *path, struct fsverity_descriptor *desc) { int ret; ret = begin_cmd(sctx, BTRFS_SEND_C_ENABLE_VERITY); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, path); TLV_PUT_U8(sctx, BTRFS_SEND_A_VERITY_ALGORITHM, le8_to_cpu(desc->hash_algorithm)); TLV_PUT_U32(sctx, BTRFS_SEND_A_VERITY_BLOCK_SIZE, 1U << le8_to_cpu(desc->log_blocksize)); TLV_PUT(sctx, BTRFS_SEND_A_VERITY_SALT_DATA, desc->salt, le8_to_cpu(desc->salt_size)); TLV_PUT(sctx, BTRFS_SEND_A_VERITY_SIG_DATA, desc->signature, le32_to_cpu(desc->sig_size)); ret = send_cmd(sctx); tlv_put_failure: out: return ret; } static int process_verity(struct send_ctx *sctx) { int ret = 0; struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; struct inode *inode; struct fs_path *p; inode = btrfs_iget(fs_info->sb, sctx->cur_ino, sctx->send_root); if (IS_ERR(inode)) return PTR_ERR(inode); ret = btrfs_get_verity_descriptor(inode, NULL, 0); if (ret < 0) goto iput; if (ret > FS_VERITY_MAX_DESCRIPTOR_SIZE) { ret = -EMSGSIZE; goto iput; } if (!sctx->verity_descriptor) { sctx->verity_descriptor = kvmalloc(FS_VERITY_MAX_DESCRIPTOR_SIZE, GFP_KERNEL); if (!sctx->verity_descriptor) { ret = -ENOMEM; goto iput; } } ret = btrfs_get_verity_descriptor(inode, sctx->verity_descriptor, ret); if (ret < 0) goto iput; p = fs_path_alloc(); if (!p) { ret = -ENOMEM; goto iput; } ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto free_path; ret = send_verity(sctx, p, sctx->verity_descriptor); if (ret < 0) goto free_path; free_path: fs_path_free(p); iput: iput(inode); return ret; } static inline u64 max_send_read_size(const struct send_ctx *sctx) { return sctx->send_max_size - SZ_16K; } static int put_data_header(struct send_ctx *sctx, u32 len) { if (WARN_ON_ONCE(sctx->put_data)) return -EINVAL; sctx->put_data = true; if (sctx->proto >= 2) { /* * Since v2, the data attribute header doesn't include a length, * it is implicitly to the end of the command. */ if (sctx->send_max_size - sctx->send_size < sizeof(__le16) + len) return -EOVERFLOW; put_unaligned_le16(BTRFS_SEND_A_DATA, sctx->send_buf + sctx->send_size); sctx->send_size += sizeof(__le16); } else { struct btrfs_tlv_header *hdr; if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len) return -EOVERFLOW; hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size); put_unaligned_le16(BTRFS_SEND_A_DATA, &hdr->tlv_type); put_unaligned_le16(len, &hdr->tlv_len); sctx->send_size += sizeof(*hdr); } return 0; } static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len) { struct btrfs_root *root = sctx->send_root; struct btrfs_fs_info *fs_info = root->fs_info; struct page *page; pgoff_t index = offset >> PAGE_SHIFT; pgoff_t last_index; unsigned pg_offset = offset_in_page(offset); int ret; ret = put_data_header(sctx, len); if (ret) return ret; last_index = (offset + len - 1) >> PAGE_SHIFT; while (index <= last_index) { unsigned cur_len = min_t(unsigned, len, PAGE_SIZE - pg_offset); page = find_lock_page(sctx->cur_inode->i_mapping, index); if (!page) { page_cache_sync_readahead(sctx->cur_inode->i_mapping, &sctx->ra, NULL, index, last_index + 1 - index); page = find_or_create_page(sctx->cur_inode->i_mapping, index, GFP_KERNEL); if (!page) { ret = -ENOMEM; break; } } if (PageReadahead(page)) page_cache_async_readahead(sctx->cur_inode->i_mapping, &sctx->ra, NULL, page_folio(page), index, last_index + 1 - index); if (!PageUptodate(page)) { btrfs_read_folio(NULL, page_folio(page)); lock_page(page); if (!PageUptodate(page)) { unlock_page(page); btrfs_err(fs_info, "send: IO error at offset %llu for inode %llu root %llu", page_offset(page), sctx->cur_ino, sctx->send_root->root_key.objectid); put_page(page); ret = -EIO; break; } } memcpy_from_page(sctx->send_buf + sctx->send_size, page, pg_offset, cur_len); unlock_page(page); put_page(page); index++; pg_offset = 0; len -= cur_len; sctx->send_size += cur_len; } return ret; } /* * Read some bytes from the current inode/file and send a write command to * user space. */ static int send_write(struct send_ctx *sctx, u64 offset, u32 len) { struct btrfs_fs_info *fs_info = sctx->send_root->fs_info; int ret = 0; struct fs_path *p; p = fs_path_alloc(); if (!p) return -ENOMEM; btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len); ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); ret = put_file_data(sctx, offset, len); if (ret < 0) goto out; ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } /* * Send a clone command to user space. */ static int send_clone(struct send_ctx *sctx, u64 offset, u32 len, struct clone_root *clone_root) { int ret = 0; struct fs_path *p; u64 gen; btrfs_debug(sctx->send_root->fs_info, "send_clone offset=%llu, len=%d, clone_root=%llu, clone_inode=%llu, clone_offset=%llu", offset, len, clone_root->root->root_key.objectid, clone_root->ino, clone_root->offset); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_CLONE); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_LEN, len); TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); if (clone_root->root == sctx->send_root) { ret = get_inode_gen(sctx->send_root, clone_root->ino, &gen); if (ret < 0) goto out; ret = get_cur_path(sctx, clone_root->ino, gen, p); } else { ret = get_inode_path(clone_root->root, clone_root->ino, p); } if (ret < 0) goto out; /* * If the parent we're using has a received_uuid set then use that as * our clone source as that is what we will look for when doing a * receive. * * This covers the case that we create a snapshot off of a received * subvolume and then use that as the parent and try to receive on a * different host. */ if (!btrfs_is_empty_uuid(clone_root->root->root_item.received_uuid)) TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, clone_root->root->root_item.received_uuid); else TLV_PUT_UUID(sctx, BTRFS_SEND_A_CLONE_UUID, clone_root->root->root_item.uuid); TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_CTRANSID, btrfs_root_ctransid(&clone_root->root->root_item)); TLV_PUT_PATH(sctx, BTRFS_SEND_A_CLONE_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_CLONE_OFFSET, clone_root->offset); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } /* * Send an update extent command to user space. */ static int send_update_extent(struct send_ctx *sctx, u64 offset, u32 len) { int ret = 0; struct fs_path *p; p = fs_path_alloc(); if (!p) return -ENOMEM; ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto out; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len); ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(p); return ret; } static int send_hole(struct send_ctx *sctx, u64 end) { struct fs_path *p = NULL; u64 read_size = max_send_read_size(sctx); u64 offset = sctx->cur_inode_last_extent; int ret = 0; /* * A hole that starts at EOF or beyond it. Since we do not yet support * fallocate (for extent preallocation and hole punching), sending a * write of zeroes starting at EOF or beyond would later require issuing * a truncate operation which would undo the write and achieve nothing. */ if (offset >= sctx->cur_inode_size) return 0; /* * Don't go beyond the inode's i_size due to prealloc extents that start * after the i_size. */ end = min_t(u64, end, sctx->cur_inode_size); if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) return send_update_extent(sctx, offset, end - offset); p = fs_path_alloc(); if (!p) return -ENOMEM; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p); if (ret < 0) goto tlv_put_failure; while (offset < end) { u64 len = min(end - offset, read_size); ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE); if (ret < 0) break; TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); ret = put_data_header(sctx, len); if (ret < 0) break; memset(sctx->send_buf + sctx->send_size, 0, len); sctx->send_size += len; ret = send_cmd(sctx); if (ret < 0) break; offset += len; } sctx->cur_inode_next_write_offset = offset; tlv_put_failure: fs_path_free(p); return ret; } static int send_encoded_inline_extent(struct send_ctx *sctx, struct btrfs_path *path, u64 offset, u64 len) { struct btrfs_root *root = sctx->send_root; struct btrfs_fs_info *fs_info = root->fs_info; struct inode *inode; struct fs_path *fspath; struct extent_buffer *leaf = path->nodes[0]; struct btrfs_key key; struct btrfs_file_extent_item *ei; u64 ram_bytes; size_t inline_size; int ret; inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root); if (IS_ERR(inode)) return PTR_ERR(inode); fspath = fs_path_alloc(); if (!fspath) { ret = -ENOMEM; goto out; } ret = begin_cmd(sctx, BTRFS_SEND_C_ENCODED_WRITE); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath); if (ret < 0) goto out; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); ram_bytes = btrfs_file_extent_ram_bytes(leaf, ei); inline_size = btrfs_file_extent_inline_item_len(leaf, path->slots[0]); TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, fspath); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN, min(key.offset + ram_bytes - offset, len)); TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN, ram_bytes); TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET, offset - key.offset); ret = btrfs_encoded_io_compression_from_extent(fs_info, btrfs_file_extent_compression(leaf, ei)); if (ret < 0) goto out; TLV_PUT_U32(sctx, BTRFS_SEND_A_COMPRESSION, ret); ret = put_data_header(sctx, inline_size); if (ret < 0) goto out; read_extent_buffer(leaf, sctx->send_buf + sctx->send_size, btrfs_file_extent_inline_start(ei), inline_size); sctx->send_size += inline_size; ret = send_cmd(sctx); tlv_put_failure: out: fs_path_free(fspath); iput(inode); return ret; } static int send_encoded_extent(struct send_ctx *sctx, struct btrfs_path *path, u64 offset, u64 len) { struct btrfs_root *root = sctx->send_root; struct btrfs_fs_info *fs_info = root->fs_info; struct inode *inode; struct fs_path *fspath; struct extent_buffer *leaf = path->nodes[0]; struct btrfs_key key; struct btrfs_file_extent_item *ei; u64 disk_bytenr, disk_num_bytes; u32 data_offset; struct btrfs_cmd_header *hdr; u32 crc; int ret; inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root); if (IS_ERR(inode)) return PTR_ERR(inode); fspath = fs_path_alloc(); if (!fspath) { ret = -ENOMEM; goto out; } ret = begin_cmd(sctx, BTRFS_SEND_C_ENCODED_WRITE); if (ret < 0) goto out; ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath); if (ret < 0) goto out; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, ei); disk_num_bytes = btrfs_file_extent_disk_num_bytes(leaf, ei); TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, fspath); TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN, min(key.offset + btrfs_file_extent_num_bytes(leaf, ei) - offset, len)); TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN, btrfs_file_extent_ram_bytes(leaf, ei)); TLV_PUT_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET, offset - key.offset + btrfs_file_extent_offset(leaf, ei)); ret = btrfs_encoded_io_compression_from_extent(fs_info, btrfs_file_extent_compression(leaf, ei)); if (ret < 0) goto out; TLV_PUT_U32(sctx, BTRFS_SEND_A_COMPRESSION, ret); TLV_PUT_U32(sctx, BTRFS_SEND_A_ENCRYPTION, 0); ret = put_data_header(sctx, disk_num_bytes); if (ret < 0) goto out; /* * We want to do I/O directly into the send buffer, so get the next page * boundary in the send buffer. This means that there may be a gap * between the beginning of the command and the file data. */ data_offset = PAGE_ALIGN(sctx->send_size); if (data_offset > sctx->send_max_size || sctx->send_max_size - data_offset < disk_num_bytes) { ret = -EOVERFLOW; goto out; } /* * Note that send_buf is a mapping of send_buf_pages, so this is really * reading into send_buf. */ ret = btrfs_encoded_read_regular_fill_pages(BTRFS_I(inode), offset, disk_bytenr, disk_num_bytes, sctx->send_buf_pages + (data_offset >> PAGE_SHIFT)); if (ret) goto out; hdr = (struct btrfs_cmd_header *)sctx->send_buf; hdr->len = cpu_to_le32(sctx->send_size + disk_num_bytes - sizeof(*hdr)); hdr->crc = 0; crc = crc32c(0, sctx->send_buf, sctx->send_size); crc = crc32c(crc, sctx->send_buf + data_offset, disk_num_bytes); hdr->crc = cpu_to_le32(crc); ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size, &sctx->send_off); if (!ret) { ret = write_buf(sctx->send_filp, sctx->send_buf + data_offset, disk_num_bytes, &sctx->send_off); } sctx->send_size = 0; sctx->put_data = false; tlv_put_failure: out: fs_path_free(fspath); iput(inode); return ret; } static int send_extent_data(struct send_ctx *sctx, struct btrfs_path *path, const u64 offset, const u64 len) { const u64 end = offset + len; struct extent_buffer *leaf = path->nodes[0]; struct btrfs_file_extent_item *ei; u64 read_size = max_send_read_size(sctx); u64 sent = 0; if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) return send_update_extent(sctx, offset, len); ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); if ((sctx->flags & BTRFS_SEND_FLAG_COMPRESSED) && btrfs_file_extent_compression(leaf, ei) != BTRFS_COMPRESS_NONE) { bool is_inline = (btrfs_file_extent_type(leaf, ei) == BTRFS_FILE_EXTENT_INLINE); /* * Send the compressed extent unless the compressed data is * larger than the decompressed data. This can happen if we're * not sending the entire extent, either because it has been * partially overwritten/truncated or because this is a part of * the extent that we couldn't clone in clone_range(). */ if (is_inline && btrfs_file_extent_inline_item_len(leaf, path->slots[0]) <= len) { return send_encoded_inline_extent(sctx, path, offset, len); } else if (!is_inline && btrfs_file_extent_disk_num_bytes(leaf, ei) <= len) { return send_encoded_extent(sctx, path, offset, len); } } if (sctx->cur_inode == NULL) { struct btrfs_root *root = sctx->send_root; sctx->cur_inode = btrfs_iget(root->fs_info->sb, sctx->cur_ino, root); if (IS_ERR(sctx->cur_inode)) { int err = PTR_ERR(sctx->cur_inode); sctx->cur_inode = NULL; return err; } memset(&sctx->ra, 0, sizeof(struct file_ra_state)); file_ra_state_init(&sctx->ra, sctx->cur_inode->i_mapping); /* * It's very likely there are no pages from this inode in the page * cache, so after reading extents and sending their data, we clean * the page cache to avoid trashing the page cache (adding pressure * to the page cache and forcing eviction of other data more useful * for applications). * * We decide if we should clean the page cache simply by checking * if the inode's mapping nrpages is 0 when we first open it, and * not by using something like filemap_range_has_page() before * reading an extent because when we ask the readahead code to * read a given file range, it may (and almost always does) read * pages from beyond that range (see the documentation for * page_cache_sync_readahead()), so it would not be reliable, * because after reading the first extent future calls to * filemap_range_has_page() would return true because the readahead * on the previous extent resulted in reading pages of the current * extent as well. */ sctx->clean_page_cache = (sctx->cur_inode->i_mapping->nrpages == 0); sctx->page_cache_clear_start = round_down(offset, PAGE_SIZE); } while (sent < len) { u64 size = min(len - sent, read_size); int ret; ret = send_write(sctx, offset + sent, size); if (ret < 0) return ret; sent += size; } if (sctx->clean_page_cache && PAGE_ALIGNED(end)) { /* * Always operate only on ranges that are a multiple of the page * size. This is not only to prevent zeroing parts of a page in * the case of subpage sector size, but also to guarantee we evict * pages, as passing a range that is smaller than page size does * not evict the respective page (only zeroes part of its content). * * Always start from the end offset of the last range cleared. * This is because the readahead code may (and very often does) * reads pages beyond the range we request for readahead. So if * we have an extent layout like this: * * [ extent A ] [ extent B ] [ extent C ] * * When we ask page_cache_sync_readahead() to read extent A, it * may also trigger reads for pages of extent B. If we are doing * an incremental send and extent B has not changed between the * parent and send snapshots, some or all of its pages may end * up being read and placed in the page cache. So when truncating * the page cache we always start from the end offset of the * previously processed extent up to the end of the current * extent. */ truncate_inode_pages_range(&sctx->cur_inode->i_data, sctx->page_cache_clear_start, end - 1); sctx->page_cache_clear_start = end; } return 0; } /* * Search for a capability xattr related to sctx->cur_ino. If the capability is * found, call send_set_xattr function to emit it. * * Return 0 if there isn't a capability, or when the capability was emitted * successfully, or < 0 if an error occurred. */ static int send_capabilities(struct send_ctx *sctx) { struct fs_path *fspath = NULL; struct btrfs_path *path; struct btrfs_dir_item *di; struct extent_buffer *leaf; unsigned long data_ptr; char *buf = NULL; int buf_len; int ret = 0; path = alloc_path_for_send(); if (!path) return -ENOMEM; di = btrfs_lookup_xattr(NULL, sctx->send_root, path, sctx->cur_ino, XATTR_NAME_CAPS, strlen(XATTR_NAME_CAPS), 0); if (!di) { /* There is no xattr for this inode */ goto out; } else if (IS_ERR(di)) { ret = PTR_ERR(di); goto out; } leaf = path->nodes[0]; buf_len = btrfs_dir_data_len(leaf, di); fspath = fs_path_alloc(); buf = kmalloc(buf_len, GFP_KERNEL); if (!fspath || !buf) { ret = -ENOMEM; goto out; } ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath); if (ret < 0) goto out; data_ptr = (unsigned long)(di + 1) + btrfs_dir_name_len(leaf, di); read_extent_buffer(leaf, buf, data_ptr, buf_len); ret = send_set_xattr(sctx, fspath, XATTR_NAME_CAPS, strlen(XATTR_NAME_CAPS), buf, buf_len); out: kfree(buf); fs_path_free(fspath); btrfs_free_path(path); return ret; } static int clone_range(struct send_ctx *sctx, struct btrfs_path *dst_path, struct clone_root *clone_root, const u64 disk_byte, u64 data_offset, u64 offset, u64 len) { struct btrfs_path *path; struct btrfs_key key; int ret; struct btrfs_inode_info info; u64 clone_src_i_size = 0; /* * Prevent cloning from a zero offset with a length matching the sector * size because in some scenarios this will make the receiver fail. * * For example, if in the source filesystem the extent at offset 0 * has a length of sectorsize and it was written using direct IO, then * it can never be an inline extent (even if compression is enabled). * Then this extent can be cloned in the original filesystem to a non * zero file offset, but it may not be possible to clone in the * destination filesystem because it can be inlined due to compression * on the destination filesystem (as the receiver's write operations are * always done using buffered IO). The same happens when the original * filesystem does not have compression enabled but the destination * filesystem has. */ if (clone_root->offset == 0 && len == sctx->send_root->fs_info->sectorsize) return send_extent_data(sctx, dst_path, offset, len); path = alloc_path_for_send(); if (!path) return -ENOMEM; /* * There are inodes that have extents that lie behind its i_size. Don't * accept clones from these extents. */ ret = get_inode_info(clone_root->root, clone_root->ino, &info); btrfs_release_path(path); if (ret < 0) goto out; clone_src_i_size = info.size; /* * We can't send a clone operation for the entire range if we find * extent items in the respective range in the source file that * refer to different extents or if we find holes. * So check for that and do a mix of clone and regular write/copy * operations if needed. * * Example: * * mkfs.btrfs -f /dev/sda * mount /dev/sda /mnt * xfs_io -f -c "pwrite -S 0xaa 0K 100K" /mnt/foo * cp --reflink=always /mnt/foo /mnt/bar * xfs_io -c "pwrite -S 0xbb 50K 50K" /mnt/foo * btrfs subvolume snapshot -r /mnt /mnt/snap * * If when we send the snapshot and we are processing file bar (which * has a higher inode number than foo) we blindly send a clone operation * for the [0, 100K[ range from foo to bar, the receiver ends up getting * a file bar that matches the content of file foo - iow, doesn't match * the content from bar in the original filesystem. */ key.objectid = clone_root->ino; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = clone_root->offset; ret = btrfs_search_slot(NULL, clone_root->root, &key, path, 0, 0); if (ret < 0) goto out; if (ret > 0 && path->slots[0] > 0) { btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1); if (key.objectid == clone_root->ino && key.type == BTRFS_EXTENT_DATA_KEY) path->slots[0]--; } while (true) { struct extent_buffer *leaf = path->nodes[0]; int slot = path->slots[0]; struct btrfs_file_extent_item *ei; u8 type; u64 ext_len; u64 clone_len; u64 clone_data_offset; bool crossed_src_i_size = false; if (slot >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(clone_root->root, path); if (ret < 0) goto out; else if (ret > 0) break; continue; } btrfs_item_key_to_cpu(leaf, &key, slot); /* * We might have an implicit trailing hole (NO_HOLES feature * enabled). We deal with it after leaving this loop. */ if (key.objectid != clone_root->ino || key.type != BTRFS_EXTENT_DATA_KEY) break; ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); type = btrfs_file_extent_type(leaf, ei); if (type == BTRFS_FILE_EXTENT_INLINE) { ext_len = btrfs_file_extent_ram_bytes(leaf, ei); ext_len = PAGE_ALIGN(ext_len); } else { ext_len = btrfs_file_extent_num_bytes(leaf, ei); } if (key.offset + ext_len <= clone_root->offset) goto next; if (key.offset > clone_root->offset) { /* Implicit hole, NO_HOLES feature enabled. */ u64 hole_len = key.offset - clone_root->offset; if (hole_len > len) hole_len = len; ret = send_extent_data(sctx, dst_path, offset, hole_len); if (ret < 0) goto out; len -= hole_len; if (len == 0) break; offset += hole_len; clone_root->offset += hole_len; data_offset += hole_len; } if (key.offset >= clone_root->offset + len) break; if (key.offset >= clone_src_i_size) break; if (key.offset + ext_len > clone_src_i_size) { ext_len = clone_src_i_size - key.offset; crossed_src_i_size = true; } clone_data_offset = btrfs_file_extent_offset(leaf, ei); if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte) { clone_root->offset = key.offset; if (clone_data_offset < data_offset && clone_data_offset + ext_len > data_offset) { u64 extent_offset; extent_offset = data_offset - clone_data_offset; ext_len -= extent_offset; clone_data_offset += extent_offset; clone_root->offset += extent_offset; } } clone_len = min_t(u64, ext_len, len); if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte && clone_data_offset == data_offset) { const u64 src_end = clone_root->offset + clone_len; const u64 sectorsize = SZ_64K; /* * We can't clone the last block, when its size is not * sector size aligned, into the middle of a file. If we * do so, the receiver will get a failure (-EINVAL) when * trying to clone or will silently corrupt the data in * the destination file if it's on a kernel without the * fix introduced by commit ac765f83f1397646 * ("Btrfs: fix data corruption due to cloning of eof * block). * * So issue a clone of the aligned down range plus a * regular write for the eof block, if we hit that case. * * Also, we use the maximum possible sector size, 64K, * because we don't know what's the sector size of the * filesystem that receives the stream, so we have to * assume the largest possible sector size. */ if (src_end == clone_src_i_size && !IS_ALIGNED(src_end, sectorsize) && offset + clone_len < sctx->cur_inode_size) { u64 slen; slen = ALIGN_DOWN(src_end - clone_root->offset, sectorsize); if (slen > 0) { ret = send_clone(sctx, offset, slen, clone_root); if (ret < 0) goto out; } ret = send_extent_data(sctx, dst_path, offset + slen, clone_len - slen); } else { ret = send_clone(sctx, offset, clone_len, clone_root); } } else if (crossed_src_i_size && clone_len < len) { /* * If we are at i_size of the clone source inode and we * can not clone from it, terminate the loop. This is * to avoid sending two write operations, one with a * length matching clone_len and the final one after * this loop with a length of len - clone_len. * * When using encoded writes (BTRFS_SEND_FLAG_COMPRESSED * was passed to the send ioctl), this helps avoid * sending an encoded write for an offset that is not * sector size aligned, in case the i_size of the source * inode is not sector size aligned. That will make the * receiver fallback to decompression of the data and * writing it using regular buffered IO, therefore while * not incorrect, it's not optimal due decompression and * possible re-compression at the receiver. */ break; } else { ret = send_extent_data(sctx, dst_path, offset, clone_len); } if (ret < 0) goto out; len -= clone_len; if (len == 0) break; offset += clone_len; clone_root->offset += clone_len; /* * If we are cloning from the file we are currently processing, * and using the send root as the clone root, we must stop once * the current clone offset reaches the current eof of the file * at the receiver, otherwise we would issue an invalid clone * operation (source range going beyond eof) and cause the * receiver to fail. So if we reach the current eof, bail out * and fallback to a regular write. */ if (clone_root->root == sctx->send_root && clone_root->ino == sctx->cur_ino && clone_root->offset >= sctx->cur_inode_next_write_offset) break; data_offset += clone_len; next: path->slots[0]++; } if (len > 0) ret = send_extent_data(sctx, dst_path, offset, len); else ret = 0; out: btrfs_free_path(path); return ret; } static int send_write_or_clone(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key, struct clone_root *clone_root) { int ret = 0; u64 offset = key->offset; u64 end; u64 bs = sctx->send_root->fs_info->sb->s_blocksize; end = min_t(u64, btrfs_file_extent_end(path), sctx->cur_inode_size); if (offset >= end) return 0; if (clone_root && IS_ALIGNED(end, bs)) { struct btrfs_file_extent_item *ei; u64 disk_byte; u64 data_offset; ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_file_extent_item); disk_byte = btrfs_file_extent_disk_bytenr(path->nodes[0], ei); data_offset = btrfs_file_extent_offset(path->nodes[0], ei); ret = clone_range(sctx, path, clone_root, disk_byte, data_offset, offset, end - offset); } else { ret = send_extent_data(sctx, path, offset, end - offset); } sctx->cur_inode_next_write_offset = end; return ret; } static int is_extent_unchanged(struct send_ctx *sctx, struct btrfs_path *left_path, struct btrfs_key *ekey) { int ret = 0; struct btrfs_key key; struct btrfs_path *path = NULL; struct extent_buffer *eb; int slot; struct btrfs_key found_key; struct btrfs_file_extent_item *ei; u64 left_disknr; u64 right_disknr; u64 left_offset; u64 right_offset; u64 left_offset_fixed; u64 left_len; u64 right_len; u64 left_gen; u64 right_gen; u8 left_type; u8 right_type; path = alloc_path_for_send(); if (!path) return -ENOMEM; eb = left_path->nodes[0]; slot = left_path->slots[0]; ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); left_type = btrfs_file_extent_type(eb, ei); if (left_type != BTRFS_FILE_EXTENT_REG) { ret = 0; goto out; } left_disknr = btrfs_file_extent_disk_bytenr(eb, ei); left_len = btrfs_file_extent_num_bytes(eb, ei); left_offset = btrfs_file_extent_offset(eb, ei); left_gen = btrfs_file_extent_generation(eb, ei); /* * Following comments will refer to these graphics. L is the left * extents which we are checking at the moment. 1-8 are the right * extents that we iterate. * * |-----L-----| * |-1-|-2a-|-3-|-4-|-5-|-6-| * * |-----L-----| * |--1--|-2b-|...(same as above) * * Alternative situation. Happens on files where extents got split. * |-----L-----| * |-----------7-----------|-6-| * * Alternative situation. Happens on files which got larger. * |-----L-----| * |-8-| * Nothing follows after 8. */ key.objectid = ekey->objectid; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = ekey->offset; ret = btrfs_search_slot_for_read(sctx->parent_root, &key, path, 0, 0); if (ret < 0) goto out; if (ret) { ret = 0; goto out; } /* * Handle special case where the right side has no extents at all. */ eb = path->nodes[0]; slot = path->slots[0]; btrfs_item_key_to_cpu(eb, &found_key, slot); if (found_key.objectid != key.objectid || found_key.type != key.type) { /* If we're a hole then just pretend nothing changed */ ret = (left_disknr) ? 0 : 1; goto out; } /* * We're now on 2a, 2b or 7. */ key = found_key; while (key.offset < ekey->offset + left_len) { ei = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); right_type = btrfs_file_extent_type(eb, ei); if (right_type != BTRFS_FILE_EXTENT_REG && right_type != BTRFS_FILE_EXTENT_INLINE) { ret = 0; goto out; } if (right_type == BTRFS_FILE_EXTENT_INLINE) { right_len = btrfs_file_extent_ram_bytes(eb, ei); right_len = PAGE_ALIGN(right_len); } else { right_len = btrfs_file_extent_num_bytes(eb, ei); } /* * Are we at extent 8? If yes, we know the extent is changed. * This may only happen on the first iteration. */ if (found_key.offset + right_len <= ekey->offset) { /* If we're a hole just pretend nothing changed */ ret = (left_disknr) ? 0 : 1; goto out; } /* * We just wanted to see if when we have an inline extent, what * follows it is a regular extent (wanted to check the above * condition for inline extents too). This should normally not * happen but it's possible for example when we have an inline * compressed extent representing data with a size matching * the page size (currently the same as sector size). */ if (right_type == BTRFS_FILE_EXTENT_INLINE) { ret = 0; goto out; } right_disknr = btrfs_file_extent_disk_bytenr(eb, ei); right_offset = btrfs_file_extent_offset(eb, ei); right_gen = btrfs_file_extent_generation(eb, ei); left_offset_fixed = left_offset; if (key.offset < ekey->offset) { /* Fix the right offset for 2a and 7. */ right_offset += ekey->offset - key.offset; } else { /* Fix the left offset for all behind 2a and 2b */ left_offset_fixed += key.offset - ekey->offset; } /* * Check if we have the same extent. */ if (left_disknr != right_disknr || left_offset_fixed != right_offset || left_gen != right_gen) { ret = 0; goto out; } /* * Go to the next extent. */ ret = btrfs_next_item(sctx->parent_root, path); if (ret < 0) goto out; if (!ret) { eb = path->nodes[0]; slot = path->slots[0]; btrfs_item_key_to_cpu(eb, &found_key, slot); } if (ret || found_key.objectid != key.objectid || found_key.type != key.type) { key.offset += right_len; break; } if (found_key.offset != key.offset + right_len) { ret = 0; goto out; } key = found_key; } /* * We're now behind the left extent (treat as unchanged) or at the end * of the right side (treat as changed). */ if (key.offset >= ekey->offset + left_len) ret = 1; else ret = 0; out: btrfs_free_path(path); return ret; } static int get_last_extent(struct send_ctx *sctx, u64 offset) { struct btrfs_path *path; struct btrfs_root *root = sctx->send_root; struct btrfs_key key; int ret; path = alloc_path_for_send(); if (!path) return -ENOMEM; sctx->cur_inode_last_extent = 0; key.objectid = sctx->cur_ino; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = offset; ret = btrfs_search_slot_for_read(root, &key, path, 0, 1); if (ret < 0) goto out; ret = 0; btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); if (key.objectid != sctx->cur_ino || key.type != BTRFS_EXTENT_DATA_KEY) goto out; sctx->cur_inode_last_extent = btrfs_file_extent_end(path); out: btrfs_free_path(path); return ret; } static int range_is_hole_in_parent(struct send_ctx *sctx, const u64 start, const u64 end) { struct btrfs_path *path; struct btrfs_key key; struct btrfs_root *root = sctx->parent_root; u64 search_start = start; int ret; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = sctx->cur_ino; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = search_start; ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret < 0) goto out; if (ret > 0 && path->slots[0] > 0) path->slots[0]--; while (search_start < end) { struct extent_buffer *leaf = path->nodes[0]; int slot = path->slots[0]; struct btrfs_file_extent_item *fi; u64 extent_end; if (slot >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(root, path); if (ret < 0) goto out; else if (ret > 0) break; continue; } btrfs_item_key_to_cpu(leaf, &key, slot); if (key.objectid < sctx->cur_ino || key.type < BTRFS_EXTENT_DATA_KEY) goto next; if (key.objectid > sctx->cur_ino || key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end) break; fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); extent_end = btrfs_file_extent_end(path); if (extent_end <= start) goto next; if (btrfs_file_extent_disk_bytenr(leaf, fi) == 0) { search_start = extent_end; goto next; } ret = 0; goto out; next: path->slots[0]++; } ret = 1; out: btrfs_free_path(path); return ret; } static int maybe_send_hole(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key) { int ret = 0; if (sctx->cur_ino != key->objectid || !need_send_hole(sctx)) return 0; if (sctx->cur_inode_last_extent == (u64)-1) { ret = get_last_extent(sctx, key->offset - 1); if (ret) return ret; } if (path->slots[0] == 0 && sctx->cur_inode_last_extent < key->offset) { /* * We might have skipped entire leafs that contained only * file extent items for our current inode. These leafs have * a generation number smaller (older) than the one in the * current leaf and the leaf our last extent came from, and * are located between these 2 leafs. */ ret = get_last_extent(sctx, key->offset - 1); if (ret) return ret; } if (sctx->cur_inode_last_extent < key->offset) { ret = range_is_hole_in_parent(sctx, sctx->cur_inode_last_extent, key->offset); if (ret < 0) return ret; else if (ret == 0) ret = send_hole(sctx, key->offset); else ret = 0; } sctx->cur_inode_last_extent = btrfs_file_extent_end(path); return ret; } static int process_extent(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key) { struct clone_root *found_clone = NULL; int ret = 0; if (S_ISLNK(sctx->cur_inode_mode)) return 0; if (sctx->parent_root && !sctx->cur_inode_new) { ret = is_extent_unchanged(sctx, path, key); if (ret < 0) goto out; if (ret) { ret = 0; goto out_hole; } } else { struct btrfs_file_extent_item *ei; u8 type; ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_file_extent_item); type = btrfs_file_extent_type(path->nodes[0], ei); if (type == BTRFS_FILE_EXTENT_PREALLOC || type == BTRFS_FILE_EXTENT_REG) { /* * The send spec does not have a prealloc command yet, * so just leave a hole for prealloc'ed extents until * we have enough commands queued up to justify rev'ing * the send spec. */ if (type == BTRFS_FILE_EXTENT_PREALLOC) { ret = 0; goto out; } /* Have a hole, just skip it. */ if (btrfs_file_extent_disk_bytenr(path->nodes[0], ei) == 0) { ret = 0; goto out; } } } ret = find_extent_clone(sctx, path, key->objectid, key->offset, sctx->cur_inode_size, &found_clone); if (ret != -ENOENT && ret < 0) goto out; ret = send_write_or_clone(sctx, path, key, found_clone); if (ret) goto out; out_hole: ret = maybe_send_hole(sctx, path, key); out: return ret; } static int process_all_extents(struct send_ctx *sctx) { int ret = 0; int iter_ret = 0; struct btrfs_root *root; struct btrfs_path *path; struct btrfs_key key; struct btrfs_key found_key; root = sctx->send_root; path = alloc_path_for_send(); if (!path) return -ENOMEM; key.objectid = sctx->cmp_key->objectid; key.type = BTRFS_EXTENT_DATA_KEY; key.offset = 0; btrfs_for_each_slot(root, &key, &found_key, path, iter_ret) { if (found_key.objectid != key.objectid || found_key.type != key.type) { ret = 0; break; } ret = process_extent(sctx, path, &found_key); if (ret < 0) break; } /* Catch error found during iteration */ if (iter_ret < 0) ret = iter_ret; btrfs_free_path(path); return ret; } static int process_recorded_refs_if_needed(struct send_ctx *sctx, int at_end, int *pending_move, int *refs_processed) { int ret = 0; if (sctx->cur_ino == 0) goto out; if (!at_end && sctx->cur_ino == sctx->cmp_key->objectid && sctx->cmp_key->type <= BTRFS_INODE_EXTREF_KEY) goto out; if (list_empty(&sctx->new_refs) && list_empty(&sctx->deleted_refs)) goto out; ret = process_recorded_refs(sctx, pending_move); if (ret < 0) goto out; *refs_processed = 1; out: return ret; } static int finish_inode_if_needed(struct send_ctx *sctx, int at_end) { int ret = 0; struct btrfs_inode_info info; u64 left_mode; u64 left_uid; u64 left_gid; u64 left_fileattr; u64 right_mode; u64 right_uid; u64 right_gid; u64 right_fileattr; int need_chmod = 0; int need_chown = 0; bool need_fileattr = false; int need_truncate = 1; int pending_move = 0; int refs_processed = 0; if (sctx->ignore_cur_inode) return 0; ret = process_recorded_refs_if_needed(sctx, at_end, &pending_move, &refs_processed); if (ret < 0) goto out; /* * We have processed the refs and thus need to advance send_progress. * Now, calls to get_cur_xxx will take the updated refs of the current * inode into account. * * On the other hand, if our current inode is a directory and couldn't * be moved/renamed because its parent was renamed/moved too and it has * a higher inode number, we can only move/rename our current inode * after we moved/renamed its parent. Therefore in this case operate on * the old path (pre move/rename) of our current inode, and the * move/rename will be performed later. */ if (refs_processed && !pending_move) sctx->send_progress = sctx->cur_ino + 1; if (sctx->cur_ino == 0 || sctx->cur_inode_deleted) goto out; if (!at_end && sctx->cmp_key->objectid == sctx->cur_ino) goto out; ret = get_inode_info(sctx->send_root, sctx->cur_ino, &info); if (ret < 0) goto out; left_mode = info.mode; left_uid = info.uid; left_gid = info.gid; left_fileattr = info.fileattr; if (!sctx->parent_root || sctx->cur_inode_new) { need_chown = 1; if (!S_ISLNK(sctx->cur_inode_mode)) need_chmod = 1; if (sctx->cur_inode_next_write_offset == sctx->cur_inode_size) need_truncate = 0; } else { u64 old_size; ret = get_inode_info(sctx->parent_root, sctx->cur_ino, &info); if (ret < 0) goto out; old_size = info.size; right_mode = info.mode; right_uid = info.uid; right_gid = info.gid; right_fileattr = info.fileattr; if (left_uid != right_uid || left_gid != right_gid) need_chown = 1; if (!S_ISLNK(sctx->cur_inode_mode) && left_mode != right_mode) need_chmod = 1; if (!S_ISLNK(sctx->cur_inode_mode) && left_fileattr != right_fileattr) need_fileattr = true; if ((old_size == sctx->cur_inode_size) || (sctx->cur_inode_size > old_size && sctx->cur_inode_next_write_offset == sctx->cur_inode_size)) need_truncate = 0; } if (S_ISREG(sctx->cur_inode_mode)) { if (need_send_hole(sctx)) { if (sctx->cur_inode_last_extent == (u64)-1 || sctx->cur_inode_last_extent < sctx->cur_inode_size) { ret = get_last_extent(sctx, (u64)-1); if (ret) goto out; } if (sctx->cur_inode_last_extent < sctx->cur_inode_size) { ret = range_is_hole_in_parent(sctx, sctx->cur_inode_last_extent, sctx->cur_inode_size); if (ret < 0) { goto out; } else if (ret == 0) { ret = send_hole(sctx, sctx->cur_inode_size); if (ret < 0) goto out; } else { /* Range is already a hole, skip. */ ret = 0; } } } if (need_truncate) { ret = send_truncate(sctx, sctx->cur_ino, sctx->cur_inode_gen, sctx->cur_inode_size); if (ret < 0) goto out; } } if (need_chown) { ret = send_chown(sctx, sctx->cur_ino, sctx->cur_inode_gen, left_uid, left_gid); if (ret < 0) goto out; } if (need_chmod) { ret = send_chmod(sctx, sctx->cur_ino, sctx->cur_inode_gen, left_mode); if (ret < 0) goto out; } if (need_fileattr) { ret = send_fileattr(sctx, sctx->cur_ino, sctx->cur_inode_gen, left_fileattr); if (ret < 0) goto out; } if (proto_cmd_ok(sctx, BTRFS_SEND_C_ENABLE_VERITY) && sctx->cur_inode_needs_verity) { ret = process_verity(sctx); if (ret < 0) goto out; } ret = send_capabilities(sctx); if (ret < 0) goto out; /* * If other directory inodes depended on our current directory * inode's move/rename, now do their move/rename operations. */ if (!is_waiting_for_move(sctx, sctx->cur_ino)) { ret = apply_children_dir_moves(sctx); if (ret) goto out; /* * Need to send that every time, no matter if it actually * changed between the two trees as we have done changes to * the inode before. If our inode is a directory and it's * waiting to be moved/renamed, we will send its utimes when * it's moved/renamed, therefore we don't need to do it here. */ sctx->send_progress = sctx->cur_ino + 1; /* * If the current inode is a non-empty directory, delay issuing * the utimes command for it, as it's very likely we have inodes * with an higher number inside it. We want to issue the utimes * command only after adding all dentries to it. */ if (S_ISDIR(sctx->cur_inode_mode) && sctx->cur_inode_size > 0) ret = cache_dir_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen); else ret = send_utimes(sctx, sctx->cur_ino, sctx->cur_inode_gen); if (ret < 0) goto out; } out: if (!ret) ret = trim_dir_utimes_cache(sctx); return ret; } static void close_current_inode(struct send_ctx *sctx) { u64 i_size; if (sctx->cur_inode == NULL) return; i_size = i_size_read(sctx->cur_inode); /* * If we are doing an incremental send, we may have extents between the * last processed extent and the i_size that have not been processed * because they haven't changed but we may have read some of their pages * through readahead, see the comments at send_extent_data(). */ if (sctx->clean_page_cache && sctx->page_cache_clear_start < i_size) truncate_inode_pages_range(&sctx->cur_inode->i_data, sctx->page_cache_clear_start, round_up(i_size, PAGE_SIZE) - 1); iput(sctx->cur_inode); sctx->cur_inode = NULL; } static int changed_inode(struct send_ctx *sctx, enum btrfs_compare_tree_result result) { int ret = 0; struct btrfs_key *key = sctx->cmp_key; struct btrfs_inode_item *left_ii = NULL; struct btrfs_inode_item *right_ii = NULL; u64 left_gen = 0; u64 right_gen = 0; close_current_inode(sctx); sctx->cur_ino = key->objectid; sctx->cur_inode_new_gen = false; sctx->cur_inode_last_extent = (u64)-1; sctx->cur_inode_next_write_offset = 0; sctx->ignore_cur_inode = false; /* * Set send_progress to current inode. This will tell all get_cur_xxx * functions that the current inode's refs are not updated yet. Later, * when process_recorded_refs is finished, it is set to cur_ino + 1. */ sctx->send_progress = sctx->cur_ino; if (result == BTRFS_COMPARE_TREE_NEW || result == BTRFS_COMPARE_TREE_CHANGED) { left_ii = btrfs_item_ptr(sctx->left_path->nodes[0], sctx->left_path->slots[0], struct btrfs_inode_item); left_gen = btrfs_inode_generation(sctx->left_path->nodes[0], left_ii); } else { right_ii = btrfs_item_ptr(sctx->right_path->nodes[0], sctx->right_path->slots[0], struct btrfs_inode_item); right_gen = btrfs_inode_generation(sctx->right_path->nodes[0], right_ii); } if (result == BTRFS_COMPARE_TREE_CHANGED) { right_ii = btrfs_item_ptr(sctx->right_path->nodes[0], sctx->right_path->slots[0], struct btrfs_inode_item); right_gen = btrfs_inode_generation(sctx->right_path->nodes[0], right_ii); /* * The cur_ino = root dir case is special here. We can't treat * the inode as deleted+reused because it would generate a * stream that tries to delete/mkdir the root dir. */ if (left_gen != right_gen && sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) sctx->cur_inode_new_gen = true; } /* * Normally we do not find inodes with a link count of zero (orphans) * because the most common case is to create a snapshot and use it * for a send operation. However other less common use cases involve * using a subvolume and send it after turning it to RO mode just * after deleting all hard links of a file while holding an open * file descriptor against it or turning a RO snapshot into RW mode, * keep an open file descriptor against a file, delete it and then * turn the snapshot back to RO mode before using it for a send * operation. The former is what the receiver operation does. * Therefore, if we want to send these snapshots soon after they're * received, we need to handle orphan inodes as well. Moreover, orphans * can appear not only in the send snapshot but also in the parent * snapshot. Here are several cases: * * Case 1: BTRFS_COMPARE_TREE_NEW * | send snapshot | action * -------------------------------- * nlink | 0 | ignore * * Case 2: BTRFS_COMPARE_TREE_DELETED * | parent snapshot | action * ---------------------------------- * nlink | 0 | as usual * Note: No unlinks will be sent because there're no paths for it. * * Case 3: BTRFS_COMPARE_TREE_CHANGED * | | parent snapshot | send snapshot | action * ----------------------------------------------------------------------- * subcase 1 | nlink | 0 | 0 | ignore * subcase 2 | nlink | >0 | 0 | new_gen(deletion) * subcase 3 | nlink | 0 | >0 | new_gen(creation) * */ if (result == BTRFS_COMPARE_TREE_NEW) { if (btrfs_inode_nlink(sctx->left_path->nodes[0], left_ii) == 0) { sctx->ignore_cur_inode = true; goto out; } sctx->cur_inode_gen = left_gen; sctx->cur_inode_new = true; sctx->cur_inode_deleted = false; sctx->cur_inode_size = btrfs_inode_size( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_rdev = btrfs_inode_rdev( sctx->left_path->nodes[0], left_ii); if (sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) ret = send_create_inode_if_needed(sctx); } else if (result == BTRFS_COMPARE_TREE_DELETED) { sctx->cur_inode_gen = right_gen; sctx->cur_inode_new = false; sctx->cur_inode_deleted = true; sctx->cur_inode_size = btrfs_inode_size( sctx->right_path->nodes[0], right_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->right_path->nodes[0], right_ii); } else if (result == BTRFS_COMPARE_TREE_CHANGED) { u32 new_nlinks, old_nlinks; new_nlinks = btrfs_inode_nlink(sctx->left_path->nodes[0], left_ii); old_nlinks = btrfs_inode_nlink(sctx->right_path->nodes[0], right_ii); if (new_nlinks == 0 && old_nlinks == 0) { sctx->ignore_cur_inode = true; goto out; } else if (new_nlinks == 0 || old_nlinks == 0) { sctx->cur_inode_new_gen = 1; } /* * We need to do some special handling in case the inode was * reported as changed with a changed generation number. This * means that the original inode was deleted and new inode * reused the same inum. So we have to treat the old inode as * deleted and the new one as new. */ if (sctx->cur_inode_new_gen) { /* * First, process the inode as if it was deleted. */ if (old_nlinks > 0) { sctx->cur_inode_gen = right_gen; sctx->cur_inode_new = false; sctx->cur_inode_deleted = true; sctx->cur_inode_size = btrfs_inode_size( sctx->right_path->nodes[0], right_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->right_path->nodes[0], right_ii); ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_DELETED); if (ret < 0) goto out; } /* * Now process the inode as if it was new. */ if (new_nlinks > 0) { sctx->cur_inode_gen = left_gen; sctx->cur_inode_new = true; sctx->cur_inode_deleted = false; sctx->cur_inode_size = btrfs_inode_size( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_rdev = btrfs_inode_rdev( sctx->left_path->nodes[0], left_ii); ret = send_create_inode_if_needed(sctx); if (ret < 0) goto out; ret = process_all_refs(sctx, BTRFS_COMPARE_TREE_NEW); if (ret < 0) goto out; /* * Advance send_progress now as we did not get * into process_recorded_refs_if_needed in the * new_gen case. */ sctx->send_progress = sctx->cur_ino + 1; /* * Now process all extents and xattrs of the * inode as if they were all new. */ ret = process_all_extents(sctx); if (ret < 0) goto out; ret = process_all_new_xattrs(sctx); if (ret < 0) goto out; } } else { sctx->cur_inode_gen = left_gen; sctx->cur_inode_new = false; sctx->cur_inode_new_gen = false; sctx->cur_inode_deleted = false; sctx->cur_inode_size = btrfs_inode_size( sctx->left_path->nodes[0], left_ii); sctx->cur_inode_mode = btrfs_inode_mode( sctx->left_path->nodes[0], left_ii); } } out: return ret; } /* * We have to process new refs before deleted refs, but compare_trees gives us * the new and deleted refs mixed. To fix this, we record the new/deleted refs * first and later process them in process_recorded_refs. * For the cur_inode_new_gen case, we skip recording completely because * changed_inode did already initiate processing of refs. The reason for this is * that in this case, compare_tree actually compares the refs of 2 different * inodes. To fix this, process_all_refs is used in changed_inode to handle all * refs of the right tree as deleted and all refs of the left tree as new. */ static int changed_ref(struct send_ctx *sctx, enum btrfs_compare_tree_result result) { int ret = 0; if (sctx->cur_ino != sctx->cmp_key->objectid) { inconsistent_snapshot_error(sctx, result, "reference"); return -EIO; } if (!sctx->cur_inode_new_gen && sctx->cur_ino != BTRFS_FIRST_FREE_OBJECTID) { if (result == BTRFS_COMPARE_TREE_NEW) ret = record_new_ref(sctx); else if (result == BTRFS_COMPARE_TREE_DELETED) ret = record_deleted_ref(sctx); else if (result == BTRFS_COMPARE_TREE_CHANGED) ret = record_changed_ref(sctx); } return ret; } /* * Process new/deleted/changed xattrs. We skip processing in the * cur_inode_new_gen case because changed_inode did already initiate processing * of xattrs. The reason is the same as in changed_ref */ static int changed_xattr(struct send_ctx *sctx, enum btrfs_compare_tree_result result) { int ret = 0; if (sctx->cur_ino != sctx->cmp_key->objectid) { inconsistent_snapshot_error(sctx, result, "xattr"); return -EIO; } if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) { if (result == BTRFS_COMPARE_TREE_NEW) ret = process_new_xattr(sctx); else if (result == BTRFS_COMPARE_TREE_DELETED) ret = process_deleted_xattr(sctx); else if (result == BTRFS_COMPARE_TREE_CHANGED) ret = process_changed_xattr(sctx); } return ret; } /* * Process new/deleted/changed extents. We skip processing in the * cur_inode_new_gen case because changed_inode did already initiate processing * of extents. The reason is the same as in changed_ref */ static int changed_extent(struct send_ctx *sctx, enum btrfs_compare_tree_result result) { int ret = 0; /* * We have found an extent item that changed without the inode item * having changed. This can happen either after relocation (where the * disk_bytenr of an extent item is replaced at * relocation.c:replace_file_extents()) or after deduplication into a * file in both the parent and send snapshots (where an extent item can * get modified or replaced with a new one). Note that deduplication * updates the inode item, but it only changes the iversion (sequence * field in the inode item) of the inode, so if a file is deduplicated * the same amount of times in both the parent and send snapshots, its * iversion becomes the same in both snapshots, whence the inode item is * the same on both snapshots. */ if (sctx->cur_ino != sctx->cmp_key->objectid) return 0; if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) { if (result != BTRFS_COMPARE_TREE_DELETED) ret = process_extent(sctx, sctx->left_path, sctx->cmp_key); } return ret; } static int changed_verity(struct send_ctx *sctx, enum btrfs_compare_tree_result result) { int ret = 0; if (!sctx->cur_inode_new_gen && !sctx->cur_inode_deleted) { if (result == BTRFS_COMPARE_TREE_NEW) sctx->cur_inode_needs_verity = true; } return ret; } static int dir_changed(struct send_ctx *sctx, u64 dir) { u64 orig_gen, new_gen; int ret; ret = get_inode_gen(sctx->send_root, dir, &new_gen); if (ret) return ret; ret = get_inode_gen(sctx->parent_root, dir, &orig_gen); if (ret) return ret; return (orig_gen != new_gen) ? 1 : 0; } static int compare_refs(struct send_ctx *sctx, struct btrfs_path *path, struct btrfs_key *key) { struct btrfs_inode_extref *extref; struct extent_buffer *leaf; u64 dirid = 0, last_dirid = 0; unsigned long ptr; u32 item_size; u32 cur_offset = 0; int ref_name_len; int ret = 0; /* Easy case, just check this one dirid */ if (key->type == BTRFS_INODE_REF_KEY) { dirid = key->offset; ret = dir_changed(sctx, dirid); goto out; } leaf = path->nodes[0]; item_size = btrfs_item_size(leaf, path->slots[0]); ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); while (cur_offset < item_size) { extref = (struct btrfs_inode_extref *)(ptr + cur_offset); dirid = btrfs_inode_extref_parent(leaf, extref); ref_name_len = btrfs_inode_extref_name_len(leaf, extref); cur_offset += ref_name_len + sizeof(*extref); if (dirid == last_dirid) continue; ret = dir_changed(sctx, dirid); if (ret) break; last_dirid = dirid; } out: return ret; } /* * Updates compare related fields in sctx and simply forwards to the actual * changed_xxx functions. */ static int changed_cb(struct btrfs_path *left_path, struct btrfs_path *right_path, struct btrfs_key *key, enum btrfs_compare_tree_result result, struct send_ctx *sctx) { int ret = 0; /* * We can not hold the commit root semaphore here. This is because in * the case of sending and receiving to the same filesystem, using a * pipe, could result in a deadlock: * * 1) The task running send blocks on the pipe because it's full; * * 2) The task running receive, which is the only consumer of the pipe, * is waiting for a transaction commit (for example due to a space * reservation when doing a write or triggering a transaction commit * when creating a subvolume); * * 3) The transaction is waiting to write lock the commit root semaphore, * but can not acquire it since it's being held at 1). * * Down this call chain we write to the pipe through kernel_write(). * The same type of problem can also happen when sending to a file that * is stored in the same filesystem - when reserving space for a write * into the file, we can trigger a transaction commit. * * Our caller has supplied us with clones of leaves from the send and * parent roots, so we're safe here from a concurrent relocation and * further reallocation of metadata extents while we are here. Below we * also assert that the leaves are clones. */ lockdep_assert_not_held(&sctx->send_root->fs_info->commit_root_sem); /* * We always have a send root, so left_path is never NULL. We will not * have a leaf when we have reached the end of the send root but have * not yet reached the end of the parent root. */ if (left_path->nodes[0]) ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED, &left_path->nodes[0]->bflags)); /* * When doing a full send we don't have a parent root, so right_path is * NULL. When doing an incremental send, we may have reached the end of * the parent root already, so we don't have a leaf at right_path. */ if (right_path && right_path->nodes[0]) ASSERT(test_bit(EXTENT_BUFFER_UNMAPPED, &right_path->nodes[0]->bflags)); if (result == BTRFS_COMPARE_TREE_SAME) { if (key->type == BTRFS_INODE_REF_KEY || key->type == BTRFS_INODE_EXTREF_KEY) { ret = compare_refs(sctx, left_path, key); if (!ret) return 0; if (ret < 0) return ret; } else if (key->type == BTRFS_EXTENT_DATA_KEY) { return maybe_send_hole(sctx, left_path, key); } else { return 0; } result = BTRFS_COMPARE_TREE_CHANGED; ret = 0; } sctx->left_path = left_path; sctx->right_path = right_path; sctx->cmp_key = key; ret = finish_inode_if_needed(sctx, 0); if (ret < 0) goto out; /* Ignore non-FS objects */ if (key->objectid == BTRFS_FREE_INO_OBJECTID || key->objectid == BTRFS_FREE_SPACE_OBJECTID) goto out; if (key->type == BTRFS_INODE_ITEM_KEY) { ret = changed_inode(sctx, result); } else if (!sctx->ignore_cur_inode) { if (key->type == BTRFS_INODE_REF_KEY || key->type == BTRFS_INODE_EXTREF_KEY) ret = changed_ref(sctx, result); else if (key->type == BTRFS_XATTR_ITEM_KEY) ret = changed_xattr(sctx, result); else if (key->type == BTRFS_EXTENT_DATA_KEY) ret = changed_extent(sctx, result); else if (key->type == BTRFS_VERITY_DESC_ITEM_KEY && key->offset == 0) ret = changed_verity(sctx, result); } out: return ret; } static int search_key_again(const struct send_ctx *sctx, struct btrfs_root *root, struct btrfs_path *path, const struct btrfs_key *key) { int ret; if (!path->need_commit_sem) lockdep_assert_held_read(&root->fs_info->commit_root_sem); /* * Roots used for send operations are readonly and no one can add, * update or remove keys from them, so we should be able to find our * key again. The only exception is deduplication, which can operate on * readonly roots and add, update or remove keys to/from them - but at * the moment we don't allow it to run in parallel with send. */ ret = btrfs_search_slot(NULL, root, key, path, 0, 0); ASSERT(ret <= 0); if (ret > 0) { btrfs_print_tree(path->nodes[path->lowest_level], false); btrfs_err(root->fs_info, "send: key (%llu %u %llu) not found in %s root %llu, lowest_level %d, slot %d", key->objectid, key->type, key->offset, (root == sctx->parent_root ? "parent" : "send"), root->root_key.objectid, path->lowest_level, path->slots[path->lowest_level]); return -EUCLEAN; } return ret; } static int full_send_tree(struct send_ctx *sctx) { int ret; struct btrfs_root *send_root = sctx->send_root; struct btrfs_key key; struct btrfs_fs_info *fs_info = send_root->fs_info; struct btrfs_path *path; path = alloc_path_for_send(); if (!path) return -ENOMEM; path->reada = READA_FORWARD_ALWAYS; key.objectid = BTRFS_FIRST_FREE_OBJECTID; key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; down_read(&fs_info->commit_root_sem); sctx->last_reloc_trans = fs_info->last_reloc_trans; up_read(&fs_info->commit_root_sem); ret = btrfs_search_slot_for_read(send_root, &key, path, 1, 0); if (ret < 0) goto out; if (ret) goto out_finish; while (1) { btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); ret = changed_cb(path, NULL, &key, BTRFS_COMPARE_TREE_NEW, sctx); if (ret < 0) goto out; down_read(&fs_info->commit_root_sem); if (fs_info->last_reloc_trans > sctx->last_reloc_trans) { sctx->last_reloc_trans = fs_info->last_reloc_trans; up_read(&fs_info->commit_root_sem); /* * A transaction used for relocating a block group was * committed or is about to finish its commit. Release * our path (leaf) and restart the search, so that we * avoid operating on any file extent items that are * stale, with a disk_bytenr that reflects a pre * relocation value. This way we avoid as much as * possible to fallback to regular writes when checking * if we can clone file ranges. */ btrfs_release_path(path); ret = search_key_again(sctx, send_root, path, &key); if (ret < 0) goto out; } else { up_read(&fs_info->commit_root_sem); } ret = btrfs_next_item(send_root, path); if (ret < 0) goto out; if (ret) { ret = 0; break; } } out_finish: ret = finish_inode_if_needed(sctx, 1); out: btrfs_free_path(path); return ret; } static int replace_node_with_clone(struct btrfs_path *path, int level) { struct extent_buffer *clone; clone = btrfs_clone_extent_buffer(path->nodes[level]); if (!clone) return -ENOMEM; free_extent_buffer(path->nodes[level]); path->nodes[level] = clone; return 0; } static int tree_move_down(struct btrfs_path *path, int *level, u64 reada_min_gen) { struct extent_buffer *eb; struct extent_buffer *parent = path->nodes[*level]; int slot = path->slots[*level]; const int nritems = btrfs_header_nritems(parent); u64 reada_max; u64 reada_done = 0; lockdep_assert_held_read(&parent->fs_info->commit_root_sem); BUG_ON(*level == 0); eb = btrfs_read_node_slot(parent, slot); if (IS_ERR(eb)) return PTR_ERR(eb); /* * Trigger readahead for the next leaves we will process, so that it is * very likely that when we need them they are already in memory and we * will not block on disk IO. For nodes we only do readahead for one, * since the time window between processing nodes is typically larger. */ reada_max = (*level == 1 ? SZ_128K : eb->fs_info->nodesize); for (slot++; slot < nritems && reada_done < reada_max; slot++) { if (btrfs_node_ptr_generation(parent, slot) > reada_min_gen) { btrfs_readahead_node_child(parent, slot); reada_done += eb->fs_info->nodesize; } } path->nodes[*level - 1] = eb; path->slots[*level - 1] = 0; (*level)--; if (*level == 0) return replace_node_with_clone(path, 0); return 0; } static int tree_move_next_or_upnext(struct btrfs_path *path, int *level, int root_level) { int ret = 0; int nritems; nritems = btrfs_header_nritems(path->nodes[*level]); path->slots[*level]++; while (path->slots[*level] >= nritems) { if (*level == root_level) { path->slots[*level] = nritems - 1; return -1; } /* move upnext */ path->slots[*level] = 0; free_extent_buffer(path->nodes[*level]); path->nodes[*level] = NULL; (*level)++; path->slots[*level]++; nritems = btrfs_header_nritems(path->nodes[*level]); ret = 1; } return ret; } /* * Returns 1 if it had to move up and next. 0 is returned if it moved only next * or down. */ static int tree_advance(struct btrfs_path *path, int *level, int root_level, int allow_down, struct btrfs_key *key, u64 reada_min_gen) { int ret; if (*level == 0 || !allow_down) { ret = tree_move_next_or_upnext(path, level, root_level); } else { ret = tree_move_down(path, level, reada_min_gen); } /* * Even if we have reached the end of a tree, ret is -1, update the key * anyway, so that in case we need to restart due to a block group * relocation, we can assert that the last key of the root node still * exists in the tree. */ if (*level == 0) btrfs_item_key_to_cpu(path->nodes[*level], key, path->slots[*level]); else btrfs_node_key_to_cpu(path->nodes[*level], key, path->slots[*level]); return ret; } static int tree_compare_item(struct btrfs_path *left_path, struct btrfs_path *right_path, char *tmp_buf) { int cmp; int len1, len2; unsigned long off1, off2; len1 = btrfs_item_size(left_path->nodes[0], left_path->slots[0]); len2 = btrfs_item_size(right_path->nodes[0], right_path->slots[0]); if (len1 != len2) return 1; off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]); off2 = btrfs_item_ptr_offset(right_path->nodes[0], right_path->slots[0]); read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1); cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1); if (cmp) return 1; return 0; } /* * A transaction used for relocating a block group was committed or is about to * finish its commit. Release our paths and restart the search, so that we are * not using stale extent buffers: * * 1) For levels > 0, we are only holding references of extent buffers, without * any locks on them, which does not prevent them from having been relocated * and reallocated after the last time we released the commit root semaphore. * The exception are the root nodes, for which we always have a clone, see * the comment at btrfs_compare_trees(); * * 2) For leaves, level 0, we are holding copies (clones) of extent buffers, so * we are safe from the concurrent relocation and reallocation. However they * can have file extent items with a pre relocation disk_bytenr value, so we * restart the start from the current commit roots and clone the new leaves so * that we get the post relocation disk_bytenr values. Not doing so, could * make us clone the wrong data in case there are new extents using the old * disk_bytenr that happen to be shared. */ static int restart_after_relocation(struct btrfs_path *left_path, struct btrfs_path *right_path, const struct btrfs_key *left_key, const struct btrfs_key *right_key, int left_level, int right_level, const struct send_ctx *sctx) { int root_level; int ret; lockdep_assert_held_read(&sctx->send_root->fs_info->commit_root_sem); btrfs_release_path(left_path); btrfs_release_path(right_path); /* * Since keys can not be added or removed to/from our roots because they * are readonly and we do not allow deduplication to run in parallel * (which can add, remove or change keys), the layout of the trees should * not change. */ left_path->lowest_level = left_level; ret = search_key_again(sctx, sctx->send_root, left_path, left_key); if (ret < 0) return ret; right_path->lowest_level = right_level; ret = search_key_again(sctx, sctx->parent_root, right_path, right_key); if (ret < 0) return ret; /* * If the lowest level nodes are leaves, clone them so that they can be * safely used by changed_cb() while not under the protection of the * commit root semaphore, even if relocation and reallocation happens in * parallel. */ if (left_level == 0) { ret = replace_node_with_clone(left_path, 0); if (ret < 0) return ret; } if (right_level == 0) { ret = replace_node_with_clone(right_path, 0); if (ret < 0) return ret; } /* * Now clone the root nodes (unless they happen to be the leaves we have * already cloned). This is to protect against concurrent snapshotting of * the send and parent roots (see the comment at btrfs_compare_trees()). */ root_level = btrfs_header_level(sctx->send_root->commit_root); if (root_level > 0) { ret = replace_node_with_clone(left_path, root_level); if (ret < 0) return ret; } root_level = btrfs_header_level(sctx->parent_root->commit_root); if (root_level > 0) { ret = replace_node_with_clone(right_path, root_level); if (ret < 0) return ret; } return 0; } /* * This function compares two trees and calls the provided callback for * every changed/new/deleted item it finds. * If shared tree blocks are encountered, whole subtrees are skipped, making * the compare pretty fast on snapshotted subvolumes. * * This currently works on commit roots only. As commit roots are read only, * we don't do any locking. The commit roots are protected with transactions. * Transactions are ended and rejoined when a commit is tried in between. * * This function checks for modifications done to the trees while comparing. * If it detects a change, it aborts immediately. */ static int btrfs_compare_trees(struct btrfs_root *left_root, struct btrfs_root *right_root, struct send_ctx *sctx) { struct btrfs_fs_info *fs_info = left_root->fs_info; int ret; int cmp; struct btrfs_path *left_path = NULL; struct btrfs_path *right_path = NULL; struct btrfs_key left_key; struct btrfs_key right_key; char *tmp_buf = NULL; int left_root_level; int right_root_level; int left_level; int right_level; int left_end_reached = 0; int right_end_reached = 0; int advance_left = 0; int advance_right = 0; u64 left_blockptr; u64 right_blockptr; u64 left_gen; u64 right_gen; u64 reada_min_gen; left_path = btrfs_alloc_path(); if (!left_path) { ret = -ENOMEM; goto out; } right_path = btrfs_alloc_path(); if (!right_path) { ret = -ENOMEM; goto out; } tmp_buf = kvmalloc(fs_info->nodesize, GFP_KERNEL); if (!tmp_buf) { ret = -ENOMEM; goto out; } left_path->search_commit_root = 1; left_path->skip_locking = 1; right_path->search_commit_root = 1; right_path->skip_locking = 1; /* * Strategy: Go to the first items of both trees. Then do * * If both trees are at level 0 * Compare keys of current items * If left < right treat left item as new, advance left tree * and repeat * If left > right treat right item as deleted, advance right tree * and repeat * If left == right do deep compare of items, treat as changed if * needed, advance both trees and repeat * If both trees are at the same level but not at level 0 * Compare keys of current nodes/leafs * If left < right advance left tree and repeat * If left > right advance right tree and repeat * If left == right compare blockptrs of the next nodes/leafs * If they match advance both trees but stay at the same level * and repeat * If they don't match advance both trees while allowing to go * deeper and repeat * If tree levels are different * Advance the tree that needs it and repeat * * Advancing a tree means: * If we are at level 0, try to go to the next slot. If that's not * possible, go one level up and repeat. Stop when we found a level * where we could go to the next slot. We may at this point be on a * node or a leaf. * * If we are not at level 0 and not on shared tree blocks, go one * level deeper. * * If we are not at level 0 and on shared tree blocks, go one slot to * the right if possible or go up and right. */ down_read(&fs_info->commit_root_sem); left_level = btrfs_header_level(left_root->commit_root); left_root_level = left_level; /* * We clone the root node of the send and parent roots to prevent races * with snapshot creation of these roots. Snapshot creation COWs the * root node of a tree, so after the transaction is committed the old * extent can be reallocated while this send operation is still ongoing. * So we clone them, under the commit root semaphore, to be race free. */ left_path->nodes[left_level] = btrfs_clone_extent_buffer(left_root->commit_root); if (!left_path->nodes[left_level]) { ret = -ENOMEM; goto out_unlock; } right_level = btrfs_header_level(right_root->commit_root); right_root_level = right_level; right_path->nodes[right_level] = btrfs_clone_extent_buffer(right_root->commit_root); if (!right_path->nodes[right_level]) { ret = -ENOMEM; goto out_unlock; } /* * Our right root is the parent root, while the left root is the "send" * root. We know that all new nodes/leaves in the left root must have * a generation greater than the right root's generation, so we trigger * readahead for those nodes and leaves of the left root, as we know we * will need to read them at some point. */ reada_min_gen = btrfs_header_generation(right_root->commit_root); if (left_level == 0) btrfs_item_key_to_cpu(left_path->nodes[left_level], &left_key, left_path->slots[left_level]); else btrfs_node_key_to_cpu(left_path->nodes[left_level], &left_key, left_path->slots[left_level]); if (right_level == 0) btrfs_item_key_to_cpu(right_path->nodes[right_level], &right_key, right_path->slots[right_level]); else btrfs_node_key_to_cpu(right_path->nodes[right_level], &right_key, right_path->slots[right_level]); sctx->last_reloc_trans = fs_info->last_reloc_trans; while (1) { if (need_resched() || rwsem_is_contended(&fs_info->commit_root_sem)) { up_read(&fs_info->commit_root_sem); cond_resched(); down_read(&fs_info->commit_root_sem); } if (fs_info->last_reloc_trans > sctx->last_reloc_trans) { ret = restart_after_relocation(left_path, right_path, &left_key, &right_key, left_level, right_level, sctx); if (ret < 0) goto out_unlock; sctx->last_reloc_trans = fs_info->last_reloc_trans; } if (advance_left && !left_end_reached) { ret = tree_advance(left_path, &left_level, left_root_level, advance_left != ADVANCE_ONLY_NEXT, &left_key, reada_min_gen); if (ret == -1) left_end_reached = ADVANCE; else if (ret < 0) goto out_unlock; advance_left = 0; } if (advance_right && !right_end_reached) { ret = tree_advance(right_path, &right_level, right_root_level, advance_right != ADVANCE_ONLY_NEXT, &right_key, reada_min_gen); if (ret == -1) right_end_reached = ADVANCE; else if (ret < 0) goto out_unlock; advance_right = 0; } if (left_end_reached && right_end_reached) { ret = 0; goto out_unlock; } else if (left_end_reached) { if (right_level == 0) { up_read(&fs_info->commit_root_sem); ret = changed_cb(left_path, right_path, &right_key, BTRFS_COMPARE_TREE_DELETED, sctx); if (ret < 0) goto out; down_read(&fs_info->commit_root_sem); } advance_right = ADVANCE; continue; } else if (right_end_reached) { if (left_level == 0) { up_read(&fs_info->commit_root_sem); ret = changed_cb(left_path, right_path, &left_key, BTRFS_COMPARE_TREE_NEW, sctx); if (ret < 0) goto out; down_read(&fs_info->commit_root_sem); } advance_left = ADVANCE; continue; } if (left_level == 0 && right_level == 0) { up_read(&fs_info->commit_root_sem); cmp = btrfs_comp_cpu_keys(&left_key, &right_key); if (cmp < 0) { ret = changed_cb(left_path, right_path, &left_key, BTRFS_COMPARE_TREE_NEW, sctx); advance_left = ADVANCE; } else if (cmp > 0) { ret = changed_cb(left_path, right_path, &right_key, BTRFS_COMPARE_TREE_DELETED, sctx); advance_right = ADVANCE; } else { enum btrfs_compare_tree_result result; WARN_ON(!extent_buffer_uptodate(left_path->nodes[0])); ret = tree_compare_item(left_path, right_path, tmp_buf); if (ret) result = BTRFS_COMPARE_TREE_CHANGED; else result = BTRFS_COMPARE_TREE_SAME; ret = changed_cb(left_path, right_path, &left_key, result, sctx); advance_left = ADVANCE; advance_right = ADVANCE; } if (ret < 0) goto out; down_read(&fs_info->commit_root_sem); } else if (left_level == right_level) { cmp = btrfs_comp_cpu_keys(&left_key, &right_key); if (cmp < 0) { advance_left = ADVANCE; } else if (cmp > 0) { advance_right = ADVANCE; } else { left_blockptr = btrfs_node_blockptr( left_path->nodes[left_level], left_path->slots[left_level]); right_blockptr = btrfs_node_blockptr( right_path->nodes[right_level], right_path->slots[right_level]); left_gen = btrfs_node_ptr_generation( left_path->nodes[left_level], left_path->slots[left_level]); right_gen = btrfs_node_ptr_generation( right_path->nodes[right_level], right_path->slots[right_level]); if (left_blockptr == right_blockptr && left_gen == right_gen) { /* * As we're on a shared block, don't * allow to go deeper. */ advance_left = ADVANCE_ONLY_NEXT; advance_right = ADVANCE_ONLY_NEXT; } else { advance_left = ADVANCE; advance_right = ADVANCE; } } } else if (left_level < right_level) { advance_right = ADVANCE; } else { advance_left = ADVANCE; } } out_unlock: up_read(&fs_info->commit_root_sem); out: btrfs_free_path(left_path); btrfs_free_path(right_path); kvfree(tmp_buf); return ret; } static int send_subvol(struct send_ctx *sctx) { int ret; if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_STREAM_HEADER)) { ret = send_header(sctx); if (ret < 0) goto out; } ret = send_subvol_begin(sctx); if (ret < 0) goto out; if (sctx->parent_root) { ret = btrfs_compare_trees(sctx->send_root, sctx->parent_root, sctx); if (ret < 0) goto out; ret = finish_inode_if_needed(sctx, 1); if (ret < 0) goto out; } else { ret = full_send_tree(sctx); if (ret < 0) goto out; } out: free_recorded_refs(sctx); return ret; } /* * If orphan cleanup did remove any orphans from a root, it means the tree * was modified and therefore the commit root is not the same as the current * root anymore. This is a problem, because send uses the commit root and * therefore can see inode items that don't exist in the current root anymore, * and for example make calls to btrfs_iget, which will do tree lookups based * on the current root and not on the commit root. Those lookups will fail, * returning a -ESTALE error, and making send fail with that error. So make * sure a send does not see any orphans we have just removed, and that it will * see the same inodes regardless of whether a transaction commit happened * before it started (meaning that the commit root will be the same as the * current root) or not. */ static int ensure_commit_roots_uptodate(struct send_ctx *sctx) { int i; struct btrfs_trans_handle *trans = NULL; again: if (sctx->parent_root && sctx->parent_root->node != sctx->parent_root->commit_root) goto commit_trans; for (i = 0; i < sctx->clone_roots_cnt; i++) if (sctx->clone_roots[i].root->node != sctx->clone_roots[i].root->commit_root) goto commit_trans; if (trans) return btrfs_end_transaction(trans); return 0; commit_trans: /* Use any root, all fs roots will get their commit roots updated. */ if (!trans) { trans = btrfs_join_transaction(sctx->send_root); if (IS_ERR(trans)) return PTR_ERR(trans); goto again; } return btrfs_commit_transaction(trans); } /* * Make sure any existing dellaloc is flushed for any root used by a send * operation so that we do not miss any data and we do not race with writeback * finishing and changing a tree while send is using the tree. This could * happen if a subvolume is in RW mode, has delalloc, is turned to RO mode and * a send operation then uses the subvolume. * After flushing delalloc ensure_commit_roots_uptodate() must be called. */ static int flush_delalloc_roots(struct send_ctx *sctx) { struct btrfs_root *root = sctx->parent_root; int ret; int i; if (root) { ret = btrfs_start_delalloc_snapshot(root, false); if (ret) return ret; btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX); } for (i = 0; i < sctx->clone_roots_cnt; i++) { root = sctx->clone_roots[i].root; ret = btrfs_start_delalloc_snapshot(root, false); if (ret) return ret; btrfs_wait_ordered_extents(root, U64_MAX, 0, U64_MAX); } return 0; } static void btrfs_root_dec_send_in_progress(struct btrfs_root* root) { spin_lock(&root->root_item_lock); root->send_in_progress--; /* * Not much left to do, we don't know why it's unbalanced and * can't blindly reset it to 0. */ if (root->send_in_progress < 0) btrfs_err(root->fs_info, "send_in_progress unbalanced %d root %llu", root->send_in_progress, root->root_key.objectid); spin_unlock(&root->root_item_lock); } static void dedupe_in_progress_warn(const struct btrfs_root *root) { btrfs_warn_rl(root->fs_info, "cannot use root %llu for send while deduplications on it are in progress (%d in progress)", root->root_key.objectid, root->dedupe_in_progress); } long btrfs_ioctl_send(struct inode *inode, struct btrfs_ioctl_send_args *arg) { int ret = 0; struct btrfs_root *send_root = BTRFS_I(inode)->root; struct btrfs_fs_info *fs_info = send_root->fs_info; struct btrfs_root *clone_root; struct send_ctx *sctx = NULL; u32 i; u64 *clone_sources_tmp = NULL; int clone_sources_to_rollback = 0; size_t alloc_size; int sort_clone_roots = 0; struct btrfs_lru_cache_entry *entry; struct btrfs_lru_cache_entry *tmp; if (!capable(CAP_SYS_ADMIN)) return -EPERM; /* * The subvolume must remain read-only during send, protect against * making it RW. This also protects against deletion. */ spin_lock(&send_root->root_item_lock); if (btrfs_root_readonly(send_root) && send_root->dedupe_in_progress) { dedupe_in_progress_warn(send_root); spin_unlock(&send_root->root_item_lock); return -EAGAIN; } send_root->send_in_progress++; spin_unlock(&send_root->root_item_lock); /* * Userspace tools do the checks and warn the user if it's * not RO. */ if (!btrfs_root_readonly(send_root)) { ret = -EPERM; goto out; } /* * Check that we don't overflow at later allocations, we request * clone_sources_count + 1 items, and compare to unsigned long inside * access_ok. Also set an upper limit for allocation size so this can't * easily exhaust memory. Max number of clone sources is about 200K. */ if (arg->clone_sources_count > SZ_8M / sizeof(struct clone_root)) { ret = -EINVAL; goto out; } if (arg->flags & ~BTRFS_SEND_FLAG_MASK) { ret = -EOPNOTSUPP; goto out; } sctx = kzalloc(sizeof(struct send_ctx), GFP_KERNEL); if (!sctx) { ret = -ENOMEM; goto out; } INIT_LIST_HEAD(&sctx->new_refs); INIT_LIST_HEAD(&sctx->deleted_refs); btrfs_lru_cache_init(&sctx->name_cache, SEND_MAX_NAME_CACHE_SIZE); btrfs_lru_cache_init(&sctx->backref_cache, SEND_MAX_BACKREF_CACHE_SIZE); btrfs_lru_cache_init(&sctx->dir_created_cache, SEND_MAX_DIR_CREATED_CACHE_SIZE); /* * This cache is periodically trimmed to a fixed size elsewhere, see * cache_dir_utimes() and trim_dir_utimes_cache(). */ btrfs_lru_cache_init(&sctx->dir_utimes_cache, 0); sctx->pending_dir_moves = RB_ROOT; sctx->waiting_dir_moves = RB_ROOT; sctx->orphan_dirs = RB_ROOT; sctx->rbtree_new_refs = RB_ROOT; sctx->rbtree_deleted_refs = RB_ROOT; sctx->flags = arg->flags; if (arg->flags & BTRFS_SEND_FLAG_VERSION) { if (arg->version > BTRFS_SEND_STREAM_VERSION) { ret = -EPROTO; goto out; } /* Zero means "use the highest version" */ sctx->proto = arg->version ?: BTRFS_SEND_STREAM_VERSION; } else { sctx->proto = 1; } if ((arg->flags & BTRFS_SEND_FLAG_COMPRESSED) && sctx->proto < 2) { ret = -EINVAL; goto out; } sctx->send_filp = fget(arg->send_fd); if (!sctx->send_filp || !(sctx->send_filp->f_mode & FMODE_WRITE)) { ret = -EBADF; goto out; } sctx->send_root = send_root; /* * Unlikely but possible, if the subvolume is marked for deletion but * is slow to remove the directory entry, send can still be started */ if (btrfs_root_dead(sctx->send_root)) { ret = -EPERM; goto out; } sctx->clone_roots_cnt = arg->clone_sources_count; if (sctx->proto >= 2) { u32 send_buf_num_pages; sctx->send_max_size = BTRFS_SEND_BUF_SIZE_V2; sctx->send_buf = vmalloc(sctx->send_max_size); if (!sctx->send_buf) { ret = -ENOMEM; goto out; } send_buf_num_pages = sctx->send_max_size >> PAGE_SHIFT; sctx->send_buf_pages = kcalloc(send_buf_num_pages, sizeof(*sctx->send_buf_pages), GFP_KERNEL); if (!sctx->send_buf_pages) { ret = -ENOMEM; goto out; } for (i = 0; i < send_buf_num_pages; i++) { sctx->send_buf_pages[i] = vmalloc_to_page(sctx->send_buf + (i << PAGE_SHIFT)); } } else { sctx->send_max_size = BTRFS_SEND_BUF_SIZE_V1; sctx->send_buf = kvmalloc(sctx->send_max_size, GFP_KERNEL); } if (!sctx->send_buf) { ret = -ENOMEM; goto out; } sctx->clone_roots = kvcalloc(arg->clone_sources_count + 1, sizeof(*sctx->clone_roots), GFP_KERNEL); if (!sctx->clone_roots) { ret = -ENOMEM; goto out; } alloc_size = array_size(sizeof(*arg->clone_sources), arg->clone_sources_count); if (arg->clone_sources_count) { clone_sources_tmp = kvmalloc(alloc_size, GFP_KERNEL); if (!clone_sources_tmp) { ret = -ENOMEM; goto out; } ret = copy_from_user(clone_sources_tmp, arg->clone_sources, alloc_size); if (ret) { ret = -EFAULT; goto out; } for (i = 0; i < arg->clone_sources_count; i++) { clone_root = btrfs_get_fs_root(fs_info, clone_sources_tmp[i], true); if (IS_ERR(clone_root)) { ret = PTR_ERR(clone_root); goto out; } spin_lock(&clone_root->root_item_lock); if (!btrfs_root_readonly(clone_root) || btrfs_root_dead(clone_root)) { spin_unlock(&clone_root->root_item_lock); btrfs_put_root(clone_root); ret = -EPERM; goto out; } if (clone_root->dedupe_in_progress) { dedupe_in_progress_warn(clone_root); spin_unlock(&clone_root->root_item_lock); btrfs_put_root(clone_root); ret = -EAGAIN; goto out; } clone_root->send_in_progress++; spin_unlock(&clone_root->root_item_lock); sctx->clone_roots[i].root = clone_root; clone_sources_to_rollback = i + 1; } kvfree(clone_sources_tmp); clone_sources_tmp = NULL; } if (arg->parent_root) { sctx->parent_root = btrfs_get_fs_root(fs_info, arg->parent_root, true); if (IS_ERR(sctx->parent_root)) { ret = PTR_ERR(sctx->parent_root); goto out; } spin_lock(&sctx->parent_root->root_item_lock); sctx->parent_root->send_in_progress++; if (!btrfs_root_readonly(sctx->parent_root) || btrfs_root_dead(sctx->parent_root)) { spin_unlock(&sctx->parent_root->root_item_lock); ret = -EPERM; goto out; } if (sctx->parent_root->dedupe_in_progress) { dedupe_in_progress_warn(sctx->parent_root); spin_unlock(&sctx->parent_root->root_item_lock); ret = -EAGAIN; goto out; } spin_unlock(&sctx->parent_root->root_item_lock); } /* * Clones from send_root are allowed, but only if the clone source * is behind the current send position. This is checked while searching * for possible clone sources. */ sctx->clone_roots[sctx->clone_roots_cnt++].root = btrfs_grab_root(sctx->send_root); /* We do a bsearch later */ sort(sctx->clone_roots, sctx->clone_roots_cnt, sizeof(*sctx->clone_roots), __clone_root_cmp_sort, NULL); sort_clone_roots = 1; ret = flush_delalloc_roots(sctx); if (ret) goto out; ret = ensure_commit_roots_uptodate(sctx); if (ret) goto out; ret = send_subvol(sctx); if (ret < 0) goto out; btrfs_lru_cache_for_each_entry_safe(&sctx->dir_utimes_cache, entry, tmp) { ret = send_utimes(sctx, entry->key, entry->gen); if (ret < 0) goto out; btrfs_lru_cache_remove(&sctx->dir_utimes_cache, entry); } if (!(sctx->flags & BTRFS_SEND_FLAG_OMIT_END_CMD)) { ret = begin_cmd(sctx, BTRFS_SEND_C_END); if (ret < 0) goto out; ret = send_cmd(sctx); if (ret < 0) goto out; } out: WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)); while (sctx && !RB_EMPTY_ROOT(&sctx->pending_dir_moves)) { struct rb_node *n; struct pending_dir_move *pm; n = rb_first(&sctx->pending_dir_moves); pm = rb_entry(n, struct pending_dir_move, node); while (!list_empty(&pm->list)) { struct pending_dir_move *pm2; pm2 = list_first_entry(&pm->list, struct pending_dir_move, list); free_pending_move(sctx, pm2); } free_pending_move(sctx, pm); } WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)); while (sctx && !RB_EMPTY_ROOT(&sctx->waiting_dir_moves)) { struct rb_node *n; struct waiting_dir_move *dm; n = rb_first(&sctx->waiting_dir_moves); dm = rb_entry(n, struct waiting_dir_move, node); rb_erase(&dm->node, &sctx->waiting_dir_moves); kfree(dm); } WARN_ON(sctx && !ret && !RB_EMPTY_ROOT(&sctx->orphan_dirs)); while (sctx && !RB_EMPTY_ROOT(&sctx->orphan_dirs)) { struct rb_node *n; struct orphan_dir_info *odi; n = rb_first(&sctx->orphan_dirs); odi = rb_entry(n, struct orphan_dir_info, node); free_orphan_dir_info(sctx, odi); } if (sort_clone_roots) { for (i = 0; i < sctx->clone_roots_cnt; i++) { btrfs_root_dec_send_in_progress( sctx->clone_roots[i].root); btrfs_put_root(sctx->clone_roots[i].root); } } else { for (i = 0; sctx && i < clone_sources_to_rollback; i++) { btrfs_root_dec_send_in_progress( sctx->clone_roots[i].root); btrfs_put_root(sctx->clone_roots[i].root); } btrfs_root_dec_send_in_progress(send_root); } if (sctx && !IS_ERR_OR_NULL(sctx->parent_root)) { btrfs_root_dec_send_in_progress(sctx->parent_root); btrfs_put_root(sctx->parent_root); } kvfree(clone_sources_tmp); if (sctx) { if (sctx->send_filp) fput(sctx->send_filp); kvfree(sctx->clone_roots); kfree(sctx->send_buf_pages); kvfree(sctx->send_buf); kvfree(sctx->verity_descriptor); close_current_inode(sctx); btrfs_lru_cache_clear(&sctx->name_cache); btrfs_lru_cache_clear(&sctx->backref_cache); btrfs_lru_cache_clear(&sctx->dir_created_cache); btrfs_lru_cache_clear(&sctx->dir_utimes_cache); kfree(sctx); } return ret; }
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