| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Chris Mason | 9827 | 45.25% | 153 | 31.87% |
| Filipe David Borba Manana | 3655 | 16.83% | 63 | 13.12% |
| Zheng Yan | 2563 | 11.80% | 17 | 3.54% |
| Jan Schmidt | 1725 | 7.94% | 26 | 5.42% |
| Josef Whiter | 1016 | 4.68% | 46 | 9.58% |
| Qu Wenruo | 671 | 3.09% | 16 | 3.33% |
| David Sterba | 479 | 2.21% | 45 | 9.38% |
| Liu Bo | 387 | 1.78% | 14 | 2.92% |
| Josef Bacik | 220 | 1.01% | 17 | 3.54% |
| Johannes Thumshirn | 139 | 0.64% | 3 | 0.62% |
| Yan Zheng | 139 | 0.64% | 4 | 0.83% |
| Nikolay Borisov | 137 | 0.63% | 16 | 3.33% |
| Arne Jansen | 101 | 0.47% | 4 | 0.83% |
| Kelley Nielsen | 91 | 0.42% | 2 | 0.42% |
| Li Dongyang | 81 | 0.37% | 1 | 0.21% |
| Jeff Mahoney | 70 | 0.32% | 8 | 1.67% |
| Miao Xie | 49 | 0.23% | 1 | 0.21% |
| Christoph Hellwig | 43 | 0.20% | 3 | 0.62% |
| Marcos Paulo de Souza | 42 | 0.19% | 2 | 0.42% |
| Boris Burkov | 35 | 0.16% | 2 | 0.42% |
| Mark Fasheh | 34 | 0.16% | 3 | 0.62% |
| Gabriel Niebler | 26 | 0.12% | 1 | 0.21% |
| Stefan Roesch | 24 | 0.11% | 1 | 0.21% |
| Tsutomu Itoh | 23 | 0.11% | 3 | 0.62% |
| Omar Sandoval | 20 | 0.09% | 2 | 0.42% |
| Shilong Wang | 19 | 0.09% | 1 | 0.21% |
| Frank Holton | 15 | 0.07% | 1 | 0.21% |
| Alexander Block | 13 | 0.06% | 1 | 0.21% |
| Daniel Dressler | 11 | 0.05% | 2 | 0.42% |
| Sage Weil | 8 | 0.04% | 1 | 0.21% |
| Anand Jain | 7 | 0.03% | 1 | 0.21% |
| Jesper Juhl | 6 | 0.03% | 1 | 0.21% |
| ChenXiaoSong | 6 | 0.03% | 1 | 0.21% |
| Julia Lawall | 6 | 0.03% | 2 | 0.42% |
| Li Zefan | 4 | 0.02% | 1 | 0.21% |
| Jens Axboe | 4 | 0.02% | 1 | 0.21% |
| Arnd Bergmann | 4 | 0.02% | 1 | 0.21% |
| Stoyan Gaydarov | 3 | 0.01% | 1 | 0.21% |
| Misono, Tomohiro | 2 | 0.01% | 1 | 0.21% |
| Dulshani Gunawardhana | 2 | 0.01% | 1 | 0.21% |
| Andrea Gelmini | 2 | 0.01% | 1 | 0.21% |
| Linus Torvalds (pre-git) | 2 | 0.01% | 1 | 0.21% |
| Byongho Lee | 1 | 0.00% | 1 | 0.21% |
| Eric Sandeen | 1 | 0.00% | 1 | 0.21% |
| Nicholas D Steeves | 1 | 0.00% | 1 | 0.21% |
| Stefan Behrens | 1 | 0.00% | 1 | 0.21% |
| Linus Torvalds | 1 | 0.00% | 1 | 0.21% |
| Randy Dunlap | 1 | 0.00% | 1 | 0.21% |
| Masahiro Yamada | 1 | 0.00% | 1 | 0.21% |
| Feifei Xu | 1 | 0.00% | 1 | 0.21% |
| Total | 21719 | 480 |
// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2007,2008 Oracle. All rights reserved. */ #include <linux/sched.h> #include <linux/slab.h> #include <linux/rbtree.h> #include <linux/mm.h> #include <linux/error-injection.h> #include "messages.h" #include "ctree.h" #include "disk-io.h" #include "transaction.h" #include "print-tree.h" #include "locking.h" #include "volumes.h" #include "qgroup.h" #include "tree-mod-log.h" #include "tree-checker.h" #include "fs.h" #include "accessors.h" #include "extent-tree.h" #include "relocation.h" #include "file-item.h" static struct kmem_cache *btrfs_path_cachep; static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int level); static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root, const struct btrfs_key *ins_key, struct btrfs_path *path, int data_size, int extend); static int push_node_left(struct btrfs_trans_handle *trans, struct extent_buffer *dst, struct extent_buffer *src, int empty); static int balance_node_right(struct btrfs_trans_handle *trans, struct extent_buffer *dst_buf, struct extent_buffer *src_buf); static const struct btrfs_csums { u16 size; const char name[10]; const char driver[12]; } btrfs_csums[] = { [BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" }, [BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" }, [BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" }, [BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b", .driver = "blake2b-256" }, }; /* * The leaf data grows from end-to-front in the node. this returns the address * of the start of the last item, which is the stop of the leaf data stack. */ static unsigned int leaf_data_end(const struct extent_buffer *leaf) { u32 nr = btrfs_header_nritems(leaf); if (nr == 0) return BTRFS_LEAF_DATA_SIZE(leaf->fs_info); return btrfs_item_offset(leaf, nr - 1); } /* * Move data in a @leaf (using memmove, safe for overlapping ranges). * * @leaf: leaf that we're doing a memmove on * @dst_offset: item data offset we're moving to * @src_offset: item data offset were' moving from * @len: length of the data we're moving * * Wrapper around memmove_extent_buffer() that takes into account the header on * the leaf. The btrfs_item offset's start directly after the header, so we * have to adjust any offsets to account for the header in the leaf. This * handles that math to simplify the callers. */ static inline void memmove_leaf_data(const struct extent_buffer *leaf, unsigned long dst_offset, unsigned long src_offset, unsigned long len) { memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) + dst_offset, btrfs_item_nr_offset(leaf, 0) + src_offset, len); } /* * Copy item data from @src into @dst at the given @offset. * * @dst: destination leaf that we're copying into * @src: source leaf that we're copying from * @dst_offset: item data offset we're copying to * @src_offset: item data offset were' copying from * @len: length of the data we're copying * * Wrapper around copy_extent_buffer() that takes into account the header on * the leaf. The btrfs_item offset's start directly after the header, so we * have to adjust any offsets to account for the header in the leaf. This * handles that math to simplify the callers. */ static inline void copy_leaf_data(const struct extent_buffer *dst, const struct extent_buffer *src, unsigned long dst_offset, unsigned long src_offset, unsigned long len) { copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, 0) + dst_offset, btrfs_item_nr_offset(src, 0) + src_offset, len); } /* * Move items in a @leaf (using memmove). * * @dst: destination leaf for the items * @dst_item: the item nr we're copying into * @src_item: the item nr we're copying from * @nr_items: the number of items to copy * * Wrapper around memmove_extent_buffer() that does the math to get the * appropriate offsets into the leaf from the item numbers. */ static inline void memmove_leaf_items(const struct extent_buffer *leaf, int dst_item, int src_item, int nr_items) { memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, dst_item), btrfs_item_nr_offset(leaf, src_item), nr_items * sizeof(struct btrfs_item)); } /* * Copy items from @src into @dst at the given @offset. * * @dst: destination leaf for the items * @src: source leaf for the items * @dst_item: the item nr we're copying into * @src_item: the item nr we're copying from * @nr_items: the number of items to copy * * Wrapper around copy_extent_buffer() that does the math to get the * appropriate offsets into the leaf from the item numbers. */ static inline void copy_leaf_items(const struct extent_buffer *dst, const struct extent_buffer *src, int dst_item, int src_item, int nr_items) { copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, dst_item), btrfs_item_nr_offset(src, src_item), nr_items * sizeof(struct btrfs_item)); } /* This exists for btrfs-progs usages. */ u16 btrfs_csum_type_size(u16 type) { return btrfs_csums[type].size; } int btrfs_super_csum_size(const struct btrfs_super_block *s) { u16 t = btrfs_super_csum_type(s); /* * csum type is validated at mount time */ return btrfs_csum_type_size(t); } const char *btrfs_super_csum_name(u16 csum_type) { /* csum type is validated at mount time */ return btrfs_csums[csum_type].name; } /* * Return driver name if defined, otherwise the name that's also a valid driver * name */ const char *btrfs_super_csum_driver(u16 csum_type) { /* csum type is validated at mount time */ return btrfs_csums[csum_type].driver[0] ? btrfs_csums[csum_type].driver : btrfs_csums[csum_type].name; } size_t __attribute_const__ btrfs_get_num_csums(void) { return ARRAY_SIZE(btrfs_csums); } struct btrfs_path *btrfs_alloc_path(void) { might_sleep(); return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS); } /* this also releases the path */ void btrfs_free_path(struct btrfs_path *p) { if (!p) return; btrfs_release_path(p); kmem_cache_free(btrfs_path_cachep, p); } /* * path release drops references on the extent buffers in the path * and it drops any locks held by this path * * It is safe to call this on paths that no locks or extent buffers held. */ noinline void btrfs_release_path(struct btrfs_path *p) { int i; for (i = 0; i < BTRFS_MAX_LEVEL; i++) { p->slots[i] = 0; if (!p->nodes[i]) continue; if (p->locks[i]) { btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]); p->locks[i] = 0; } free_extent_buffer(p->nodes[i]); p->nodes[i] = NULL; } } /* * We want the transaction abort to print stack trace only for errors where the * cause could be a bug, eg. due to ENOSPC, and not for common errors that are * caused by external factors. */ bool __cold abort_should_print_stack(int error) { switch (error) { case -EIO: case -EROFS: case -ENOMEM: return false; } return true; } /* * safely gets a reference on the root node of a tree. A lock * is not taken, so a concurrent writer may put a different node * at the root of the tree. See btrfs_lock_root_node for the * looping required. * * The extent buffer returned by this has a reference taken, so * it won't disappear. It may stop being the root of the tree * at any time because there are no locks held. */ struct extent_buffer *btrfs_root_node(struct btrfs_root *root) { struct extent_buffer *eb; while (1) { rcu_read_lock(); eb = rcu_dereference(root->node); /* * RCU really hurts here, we could free up the root node because * it was COWed but we may not get the new root node yet so do * the inc_not_zero dance and if it doesn't work then * synchronize_rcu and try again. */ if (atomic_inc_not_zero(&eb->refs)) { rcu_read_unlock(); break; } rcu_read_unlock(); synchronize_rcu(); } return eb; } /* * Cowonly root (not-shareable trees, everything not subvolume or reloc roots), * just get put onto a simple dirty list. Transaction walks this list to make * sure they get properly updated on disk. */ static void add_root_to_dirty_list(struct btrfs_root *root) { struct btrfs_fs_info *fs_info = root->fs_info; if (test_bit(BTRFS_ROOT_DIRTY, &root->state) || !test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state)) return; spin_lock(&fs_info->trans_lock); if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) { /* Want the extent tree to be the last on the list */ if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID) list_move_tail(&root->dirty_list, &fs_info->dirty_cowonly_roots); else list_move(&root->dirty_list, &fs_info->dirty_cowonly_roots); } spin_unlock(&fs_info->trans_lock); } /* * used by snapshot creation to make a copy of a root for a tree with * a given objectid. The buffer with the new root node is returned in * cow_ret, and this func returns zero on success or a negative error code. */ int btrfs_copy_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, struct extent_buffer **cow_ret, u64 new_root_objectid) { struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *cow; int ret = 0; int level; struct btrfs_disk_key disk_key; u64 reloc_src_root = 0; WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && trans->transid != fs_info->running_transaction->transid); WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && trans->transid != root->last_trans); level = btrfs_header_level(buf); if (level == 0) btrfs_item_key(buf, &disk_key, 0); else btrfs_node_key(buf, &disk_key, 0); if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) reloc_src_root = btrfs_header_owner(buf); cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid, &disk_key, level, buf->start, 0, reloc_src_root, BTRFS_NESTING_NEW_ROOT); if (IS_ERR(cow)) return PTR_ERR(cow); copy_extent_buffer_full(cow, buf); btrfs_set_header_bytenr(cow, cow->start); btrfs_set_header_generation(cow, trans->transid); btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | BTRFS_HEADER_FLAG_RELOC); if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); else btrfs_set_header_owner(cow, new_root_objectid); write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid); WARN_ON(btrfs_header_generation(buf) > trans->transid); if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) ret = btrfs_inc_ref(trans, root, cow, 1); else ret = btrfs_inc_ref(trans, root, cow, 0); if (ret) { btrfs_tree_unlock(cow); free_extent_buffer(cow); btrfs_abort_transaction(trans, ret); return ret; } btrfs_mark_buffer_dirty(trans, cow); *cow_ret = cow; return 0; } /* * check if the tree block can be shared by multiple trees */ int btrfs_block_can_be_shared(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf) { /* * Tree blocks not in shareable trees and tree roots are never shared. * If a block was allocated after the last snapshot and the block was * not allocated by tree relocation, we know the block is not shared. */ if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && buf != root->node && (btrfs_header_generation(buf) <= btrfs_root_last_snapshot(&root->root_item) || btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) { if (buf != root->commit_root) return 1; /* * An extent buffer that used to be the commit root may still be * shared because the tree height may have increased and it * became a child of a higher level root. This can happen when * snapshotting a subvolume created in the current transaction. */ if (btrfs_header_generation(buf) == trans->transid) return 1; } return 0; } static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, struct extent_buffer *cow, int *last_ref) { struct btrfs_fs_info *fs_info = root->fs_info; u64 refs; u64 owner; u64 flags; u64 new_flags = 0; int ret; /* * Backrefs update rules: * * Always use full backrefs for extent pointers in tree block * allocated by tree relocation. * * If a shared tree block is no longer referenced by its owner * tree (btrfs_header_owner(buf) == root->root_key.objectid), * use full backrefs for extent pointers in tree block. * * If a tree block is been relocating * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID), * use full backrefs for extent pointers in tree block. * The reason for this is some operations (such as drop tree) * are only allowed for blocks use full backrefs. */ if (btrfs_block_can_be_shared(trans, root, buf)) { ret = btrfs_lookup_extent_info(trans, fs_info, buf->start, btrfs_header_level(buf), 1, &refs, &flags, NULL); if (ret) return ret; if (unlikely(refs == 0)) { btrfs_crit(fs_info, "found 0 references for tree block at bytenr %llu level %d root %llu", buf->start, btrfs_header_level(buf), btrfs_root_id(root)); ret = -EUCLEAN; btrfs_abort_transaction(trans, ret); return ret; } } else { refs = 1; if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) flags = BTRFS_BLOCK_FLAG_FULL_BACKREF; else flags = 0; } owner = btrfs_header_owner(buf); BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID && !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); if (refs > 1) { if ((owner == root->root_key.objectid || root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) { ret = btrfs_inc_ref(trans, root, buf, 1); if (ret) return ret; if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { ret = btrfs_dec_ref(trans, root, buf, 0); if (ret) return ret; ret = btrfs_inc_ref(trans, root, cow, 1); if (ret) return ret; } new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF; } else { if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) ret = btrfs_inc_ref(trans, root, cow, 1); else ret = btrfs_inc_ref(trans, root, cow, 0); if (ret) return ret; } if (new_flags != 0) { ret = btrfs_set_disk_extent_flags(trans, buf, new_flags); if (ret) return ret; } } else { if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) { if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) ret = btrfs_inc_ref(trans, root, cow, 1); else ret = btrfs_inc_ref(trans, root, cow, 0); if (ret) return ret; ret = btrfs_dec_ref(trans, root, buf, 1); if (ret) return ret; } btrfs_clear_buffer_dirty(trans, buf); *last_ref = 1; } return 0; } /* * does the dirty work in cow of a single block. The parent block (if * supplied) is updated to point to the new cow copy. The new buffer is marked * dirty and returned locked. If you modify the block it needs to be marked * dirty again. * * search_start -- an allocation hint for the new block * * empty_size -- a hint that you plan on doing more cow. This is the size in * bytes the allocator should try to find free next to the block it returns. * This is just a hint and may be ignored by the allocator. */ int btrfs_force_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, struct extent_buffer *parent, int parent_slot, struct extent_buffer **cow_ret, u64 search_start, u64 empty_size, enum btrfs_lock_nesting nest) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_disk_key disk_key; struct extent_buffer *cow; int level, ret; int last_ref = 0; int unlock_orig = 0; u64 parent_start = 0; u64 reloc_src_root = 0; if (*cow_ret == buf) unlock_orig = 1; btrfs_assert_tree_write_locked(buf); WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && trans->transid != fs_info->running_transaction->transid); WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && trans->transid != root->last_trans); level = btrfs_header_level(buf); if (level == 0) btrfs_item_key(buf, &disk_key, 0); else btrfs_node_key(buf, &disk_key, 0); if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) { if (parent) parent_start = parent->start; reloc_src_root = btrfs_header_owner(buf); } cow = btrfs_alloc_tree_block(trans, root, parent_start, root->root_key.objectid, &disk_key, level, search_start, empty_size, reloc_src_root, nest); if (IS_ERR(cow)) return PTR_ERR(cow); /* cow is set to blocking by btrfs_init_new_buffer */ copy_extent_buffer_full(cow, buf); btrfs_set_header_bytenr(cow, cow->start); btrfs_set_header_generation(cow, trans->transid); btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | BTRFS_HEADER_FLAG_RELOC); if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); else btrfs_set_header_owner(cow, root->root_key.objectid); write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid); ret = update_ref_for_cow(trans, root, buf, cow, &last_ref); if (ret) { btrfs_tree_unlock(cow); free_extent_buffer(cow); btrfs_abort_transaction(trans, ret); return ret; } if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { ret = btrfs_reloc_cow_block(trans, root, buf, cow); if (ret) { btrfs_tree_unlock(cow); free_extent_buffer(cow); btrfs_abort_transaction(trans, ret); return ret; } } if (buf == root->node) { WARN_ON(parent && parent != buf); if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) parent_start = buf->start; ret = btrfs_tree_mod_log_insert_root(root->node, cow, true); if (ret < 0) { btrfs_tree_unlock(cow); free_extent_buffer(cow); btrfs_abort_transaction(trans, ret); return ret; } atomic_inc(&cow->refs); rcu_assign_pointer(root->node, cow); btrfs_free_tree_block(trans, btrfs_root_id(root), buf, parent_start, last_ref); free_extent_buffer(buf); add_root_to_dirty_list(root); } else { WARN_ON(trans->transid != btrfs_header_generation(parent)); ret = btrfs_tree_mod_log_insert_key(parent, parent_slot, BTRFS_MOD_LOG_KEY_REPLACE); if (ret) { btrfs_tree_unlock(cow); free_extent_buffer(cow); btrfs_abort_transaction(trans, ret); return ret; } btrfs_set_node_blockptr(parent, parent_slot, cow->start); btrfs_set_node_ptr_generation(parent, parent_slot, trans->transid); btrfs_mark_buffer_dirty(trans, parent); if (last_ref) { ret = btrfs_tree_mod_log_free_eb(buf); if (ret) { btrfs_tree_unlock(cow); free_extent_buffer(cow); btrfs_abort_transaction(trans, ret); return ret; } } btrfs_free_tree_block(trans, btrfs_root_id(root), buf, parent_start, last_ref); } if (unlock_orig) btrfs_tree_unlock(buf); free_extent_buffer_stale(buf); btrfs_mark_buffer_dirty(trans, cow); *cow_ret = cow; return 0; } static inline int should_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf) { if (btrfs_is_testing(root->fs_info)) return 0; /* Ensure we can see the FORCE_COW bit */ smp_mb__before_atomic(); /* * We do not need to cow a block if * 1) this block is not created or changed in this transaction; * 2) this block does not belong to TREE_RELOC tree; * 3) the root is not forced COW. * * What is forced COW: * when we create snapshot during committing the transaction, * after we've finished copying src root, we must COW the shared * block to ensure the metadata consistency. */ if (btrfs_header_generation(buf) == trans->transid && !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) && !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID && btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) && !test_bit(BTRFS_ROOT_FORCE_COW, &root->state)) return 0; return 1; } /* * COWs a single block, see btrfs_force_cow_block() for the real work. * This version of it has extra checks so that a block isn't COWed more than * once per transaction, as long as it hasn't been written yet */ int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf, struct extent_buffer *parent, int parent_slot, struct extent_buffer **cow_ret, enum btrfs_lock_nesting nest) { struct btrfs_fs_info *fs_info = root->fs_info; u64 search_start; int ret; if (unlikely(test_bit(BTRFS_ROOT_DELETING, &root->state))) { btrfs_abort_transaction(trans, -EUCLEAN); btrfs_crit(fs_info, "attempt to COW block %llu on root %llu that is being deleted", buf->start, btrfs_root_id(root)); return -EUCLEAN; } /* * COWing must happen through a running transaction, which always * matches the current fs generation (it's a transaction with a state * less than TRANS_STATE_UNBLOCKED). If it doesn't, then turn the fs * into error state to prevent the commit of any transaction. */ if (unlikely(trans->transaction != fs_info->running_transaction || trans->transid != fs_info->generation)) { btrfs_abort_transaction(trans, -EUCLEAN); btrfs_crit(fs_info, "unexpected transaction when attempting to COW block %llu on root %llu, transaction %llu running transaction %llu fs generation %llu", buf->start, btrfs_root_id(root), trans->transid, fs_info->running_transaction->transid, fs_info->generation); return -EUCLEAN; } if (!should_cow_block(trans, root, buf)) { *cow_ret = buf; return 0; } search_start = round_down(buf->start, SZ_1G); /* * Before CoWing this block for later modification, check if it's * the subtree root and do the delayed subtree trace if needed. * * Also We don't care about the error, as it's handled internally. */ btrfs_qgroup_trace_subtree_after_cow(trans, root, buf); ret = btrfs_force_cow_block(trans, root, buf, parent, parent_slot, cow_ret, search_start, 0, nest); trace_btrfs_cow_block(root, buf, *cow_ret); return ret; } ALLOW_ERROR_INJECTION(btrfs_cow_block, ERRNO); /* * same as comp_keys only with two btrfs_key's */ int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2) { if (k1->objectid > k2->objectid) return 1; if (k1->objectid < k2->objectid) return -1; if (k1->type > k2->type) return 1; if (k1->type < k2->type) return -1; if (k1->offset > k2->offset) return 1; if (k1->offset < k2->offset) return -1; return 0; } /* * Search for a key in the given extent_buffer. * * The lower boundary for the search is specified by the slot number @first_slot. * Use a value of 0 to search over the whole extent buffer. Works for both * leaves and nodes. * * The slot in the extent buffer is returned via @slot. If the key exists in the * extent buffer, then @slot will point to the slot where the key is, otherwise * it points to the slot where you would insert the key. * * Slot may point to the total number of items (i.e. one position beyond the last * key) if the key is bigger than the last key in the extent buffer. */ int btrfs_bin_search(struct extent_buffer *eb, int first_slot, const struct btrfs_key *key, int *slot) { unsigned long p; int item_size; /* * Use unsigned types for the low and high slots, so that we get a more * efficient division in the search loop below. */ u32 low = first_slot; u32 high = btrfs_header_nritems(eb); int ret; const int key_size = sizeof(struct btrfs_disk_key); if (unlikely(low > high)) { btrfs_err(eb->fs_info, "%s: low (%u) > high (%u) eb %llu owner %llu level %d", __func__, low, high, eb->start, btrfs_header_owner(eb), btrfs_header_level(eb)); return -EINVAL; } if (btrfs_header_level(eb) == 0) { p = offsetof(struct btrfs_leaf, items); item_size = sizeof(struct btrfs_item); } else { p = offsetof(struct btrfs_node, ptrs); item_size = sizeof(struct btrfs_key_ptr); } while (low < high) { unsigned long oip; unsigned long offset; struct btrfs_disk_key *tmp; struct btrfs_disk_key unaligned; int mid; mid = (low + high) / 2; offset = p + mid * item_size; oip = offset_in_page(offset); if (oip + key_size <= PAGE_SIZE) { const unsigned long idx = get_eb_page_index(offset); char *kaddr = page_address(eb->pages[idx]); oip = get_eb_offset_in_page(eb, offset); tmp = (struct btrfs_disk_key *)(kaddr + oip); } else { read_extent_buffer(eb, &unaligned, offset, key_size); tmp = &unaligned; } ret = btrfs_comp_keys(tmp, key); if (ret < 0) low = mid + 1; else if (ret > 0) high = mid; else { *slot = mid; return 0; } } *slot = low; return 1; } static void root_add_used_bytes(struct btrfs_root *root) { spin_lock(&root->accounting_lock); btrfs_set_root_used(&root->root_item, btrfs_root_used(&root->root_item) + root->fs_info->nodesize); spin_unlock(&root->accounting_lock); } static void root_sub_used_bytes(struct btrfs_root *root) { spin_lock(&root->accounting_lock); btrfs_set_root_used(&root->root_item, btrfs_root_used(&root->root_item) - root->fs_info->nodesize); spin_unlock(&root->accounting_lock); } /* given a node and slot number, this reads the blocks it points to. The * extent buffer is returned with a reference taken (but unlocked). */ struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent, int slot) { int level = btrfs_header_level(parent); struct btrfs_tree_parent_check check = { 0 }; struct extent_buffer *eb; if (slot < 0 || slot >= btrfs_header_nritems(parent)) return ERR_PTR(-ENOENT); ASSERT(level); check.level = level - 1; check.transid = btrfs_node_ptr_generation(parent, slot); check.owner_root = btrfs_header_owner(parent); check.has_first_key = true; btrfs_node_key_to_cpu(parent, &check.first_key, slot); eb = read_tree_block(parent->fs_info, btrfs_node_blockptr(parent, slot), &check); if (IS_ERR(eb)) return eb; if (!extent_buffer_uptodate(eb)) { free_extent_buffer(eb); return ERR_PTR(-EIO); } return eb; } /* * node level balancing, used to make sure nodes are in proper order for * item deletion. We balance from the top down, so we have to make sure * that a deletion won't leave an node completely empty later on. */ static noinline int balance_level(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int level) { struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *right = NULL; struct extent_buffer *mid; struct extent_buffer *left = NULL; struct extent_buffer *parent = NULL; int ret = 0; int wret; int pslot; int orig_slot = path->slots[level]; u64 orig_ptr; ASSERT(level > 0); mid = path->nodes[level]; WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK); WARN_ON(btrfs_header_generation(mid) != trans->transid); orig_ptr = btrfs_node_blockptr(mid, orig_slot); if (level < BTRFS_MAX_LEVEL - 1) { parent = path->nodes[level + 1]; pslot = path->slots[level + 1]; } /* * deal with the case where there is only one pointer in the root * by promoting the node below to a root */ if (!parent) { struct extent_buffer *child; if (btrfs_header_nritems(mid) != 1) return 0; /* promote the child to a root */ child = btrfs_read_node_slot(mid, 0); if (IS_ERR(child)) { ret = PTR_ERR(child); goto out; } btrfs_tree_lock(child); ret = btrfs_cow_block(trans, root, child, mid, 0, &child, BTRFS_NESTING_COW); if (ret) { btrfs_tree_unlock(child); free_extent_buffer(child); goto out; } ret = btrfs_tree_mod_log_insert_root(root->node, child, true); if (ret < 0) { btrfs_tree_unlock(child); free_extent_buffer(child); btrfs_abort_transaction(trans, ret); goto out; } rcu_assign_pointer(root->node, child); add_root_to_dirty_list(root); btrfs_tree_unlock(child); path->locks[level] = 0; path->nodes[level] = NULL; btrfs_clear_buffer_dirty(trans, mid); btrfs_tree_unlock(mid); /* once for the path */ free_extent_buffer(mid); root_sub_used_bytes(root); btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1); /* once for the root ptr */ free_extent_buffer_stale(mid); return 0; } if (btrfs_header_nritems(mid) > BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4) return 0; if (pslot) { left = btrfs_read_node_slot(parent, pslot - 1); if (IS_ERR(left)) { ret = PTR_ERR(left); left = NULL; goto out; } __btrfs_tree_lock(left, BTRFS_NESTING_LEFT); wret = btrfs_cow_block(trans, root, left, parent, pslot - 1, &left, BTRFS_NESTING_LEFT_COW); if (wret) { ret = wret; goto out; } } if (pslot + 1 < btrfs_header_nritems(parent)) { right = btrfs_read_node_slot(parent, pslot + 1); if (IS_ERR(right)) { ret = PTR_ERR(right); right = NULL; goto out; } __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT); wret = btrfs_cow_block(trans, root, right, parent, pslot + 1, &right, BTRFS_NESTING_RIGHT_COW); if (wret) { ret = wret; goto out; } } /* first, try to make some room in the middle buffer */ if (left) { orig_slot += btrfs_header_nritems(left); wret = push_node_left(trans, left, mid, 1); if (wret < 0) ret = wret; } /* * then try to empty the right most buffer into the middle */ if (right) { wret = push_node_left(trans, mid, right, 1); if (wret < 0 && wret != -ENOSPC) ret = wret; if (btrfs_header_nritems(right) == 0) { btrfs_clear_buffer_dirty(trans, right); btrfs_tree_unlock(right); ret = btrfs_del_ptr(trans, root, path, level + 1, pslot + 1); if (ret < 0) { free_extent_buffer_stale(right); right = NULL; goto out; } root_sub_used_bytes(root); btrfs_free_tree_block(trans, btrfs_root_id(root), right, 0, 1); free_extent_buffer_stale(right); right = NULL; } else { struct btrfs_disk_key right_key; btrfs_node_key(right, &right_key, 0); ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1, BTRFS_MOD_LOG_KEY_REPLACE); if (ret < 0) { btrfs_abort_transaction(trans, ret); goto out; } btrfs_set_node_key(parent, &right_key, pslot + 1); btrfs_mark_buffer_dirty(trans, parent); } } if (btrfs_header_nritems(mid) == 1) { /* * we're not allowed to leave a node with one item in the * tree during a delete. A deletion from lower in the tree * could try to delete the only pointer in this node. * So, pull some keys from the left. * There has to be a left pointer at this point because * otherwise we would have pulled some pointers from the * right */ if (unlikely(!left)) { btrfs_crit(fs_info, "missing left child when middle child only has 1 item, parent bytenr %llu level %d mid bytenr %llu root %llu", parent->start, btrfs_header_level(parent), mid->start, btrfs_root_id(root)); ret = -EUCLEAN; btrfs_abort_transaction(trans, ret); goto out; } wret = balance_node_right(trans, mid, left); if (wret < 0) { ret = wret; goto out; } if (wret == 1) { wret = push_node_left(trans, left, mid, 1); if (wret < 0) ret = wret; } BUG_ON(wret == 1); } if (btrfs_header_nritems(mid) == 0) { btrfs_clear_buffer_dirty(trans, mid); btrfs_tree_unlock(mid); ret = btrfs_del_ptr(trans, root, path, level + 1, pslot); if (ret < 0) { free_extent_buffer_stale(mid); mid = NULL; goto out; } root_sub_used_bytes(root); btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1); free_extent_buffer_stale(mid); mid = NULL; } else { /* update the parent key to reflect our changes */ struct btrfs_disk_key mid_key; btrfs_node_key(mid, &mid_key, 0); ret = btrfs_tree_mod_log_insert_key(parent, pslot, BTRFS_MOD_LOG_KEY_REPLACE); if (ret < 0) { btrfs_abort_transaction(trans, ret); goto out; } btrfs_set_node_key(parent, &mid_key, pslot); btrfs_mark_buffer_dirty(trans, parent); } /* update the path */ if (left) { if (btrfs_header_nritems(left) > orig_slot) { atomic_inc(&left->refs); /* left was locked after cow */ path->nodes[level] = left; path->slots[level + 1] -= 1; path->slots[level] = orig_slot; if (mid) { btrfs_tree_unlock(mid); free_extent_buffer(mid); } } else { orig_slot -= btrfs_header_nritems(left); path->slots[level] = orig_slot; } } /* double check we haven't messed things up */ if (orig_ptr != btrfs_node_blockptr(path->nodes[level], path->slots[level])) BUG(); out: if (right) { btrfs_tree_unlock(right); free_extent_buffer(right); } if (left) { if (path->nodes[level] != left) btrfs_tree_unlock(left); free_extent_buffer(left); } return ret; } /* Node balancing for insertion. Here we only split or push nodes around * when they are completely full. This is also done top down, so we * have to be pessimistic. */ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int level) { struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *right = NULL; struct extent_buffer *mid; struct extent_buffer *left = NULL; struct extent_buffer *parent = NULL; int ret = 0; int wret; int pslot; int orig_slot = path->slots[level]; if (level == 0) return 1; mid = path->nodes[level]; WARN_ON(btrfs_header_generation(mid) != trans->transid); if (level < BTRFS_MAX_LEVEL - 1) { parent = path->nodes[level + 1]; pslot = path->slots[level + 1]; } if (!parent) return 1; /* first, try to make some room in the middle buffer */ if (pslot) { u32 left_nr; left = btrfs_read_node_slot(parent, pslot - 1); if (IS_ERR(left)) return PTR_ERR(left); __btrfs_tree_lock(left, BTRFS_NESTING_LEFT); left_nr = btrfs_header_nritems(left); if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) { wret = 1; } else { ret = btrfs_cow_block(trans, root, left, parent, pslot - 1, &left, BTRFS_NESTING_LEFT_COW); if (ret) wret = 1; else { wret = push_node_left(trans, left, mid, 0); } } if (wret < 0) ret = wret; if (wret == 0) { struct btrfs_disk_key disk_key; orig_slot += left_nr; btrfs_node_key(mid, &disk_key, 0); ret = btrfs_tree_mod_log_insert_key(parent, pslot, BTRFS_MOD_LOG_KEY_REPLACE); if (ret < 0) { btrfs_tree_unlock(left); free_extent_buffer(left); btrfs_abort_transaction(trans, ret); return ret; } btrfs_set_node_key(parent, &disk_key, pslot); btrfs_mark_buffer_dirty(trans, parent); if (btrfs_header_nritems(left) > orig_slot) { path->nodes[level] = left; path->slots[level + 1] -= 1; path->slots[level] = orig_slot; btrfs_tree_unlock(mid); free_extent_buffer(mid); } else { orig_slot -= btrfs_header_nritems(left); path->slots[level] = orig_slot; btrfs_tree_unlock(left); free_extent_buffer(left); } return 0; } btrfs_tree_unlock(left); free_extent_buffer(left); } /* * then try to empty the right most buffer into the middle */ if (pslot + 1 < btrfs_header_nritems(parent)) { u32 right_nr; right = btrfs_read_node_slot(parent, pslot + 1); if (IS_ERR(right)) return PTR_ERR(right); __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT); right_nr = btrfs_header_nritems(right); if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) { wret = 1; } else { ret = btrfs_cow_block(trans, root, right, parent, pslot + 1, &right, BTRFS_NESTING_RIGHT_COW); if (ret) wret = 1; else { wret = balance_node_right(trans, right, mid); } } if (wret < 0) ret = wret; if (wret == 0) { struct btrfs_disk_key disk_key; btrfs_node_key(right, &disk_key, 0); ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1, BTRFS_MOD_LOG_KEY_REPLACE); if (ret < 0) { btrfs_tree_unlock(right); free_extent_buffer(right); btrfs_abort_transaction(trans, ret); return ret; } btrfs_set_node_key(parent, &disk_key, pslot + 1); btrfs_mark_buffer_dirty(trans, parent); if (btrfs_header_nritems(mid) <= orig_slot) { path->nodes[level] = right; path->slots[level + 1] += 1; path->slots[level] = orig_slot - btrfs_header_nritems(mid); btrfs_tree_unlock(mid); free_extent_buffer(mid); } else { btrfs_tree_unlock(right); free_extent_buffer(right); } return 0; } btrfs_tree_unlock(right); free_extent_buffer(right); } return 1; } /* * readahead one full node of leaves, finding things that are close * to the block in 'slot', and triggering ra on them. */ static void reada_for_search(struct btrfs_fs_info *fs_info, struct btrfs_path *path, int level, int slot, u64 objectid) { struct extent_buffer *node; struct btrfs_disk_key disk_key; u32 nritems; u64 search; u64 target; u64 nread = 0; u64 nread_max; u32 nr; u32 blocksize; u32 nscan = 0; if (level != 1 && path->reada != READA_FORWARD_ALWAYS) return; if (!path->nodes[level]) return; node = path->nodes[level]; /* * Since the time between visiting leaves is much shorter than the time * between visiting nodes, limit read ahead of nodes to 1, to avoid too * much IO at once (possibly random). */ if (path->reada == READA_FORWARD_ALWAYS) { if (level > 1) nread_max = node->fs_info->nodesize; else nread_max = SZ_128K; } else { nread_max = SZ_64K; } search = btrfs_node_blockptr(node, slot); blocksize = fs_info->nodesize; if (path->reada != READA_FORWARD_ALWAYS) { struct extent_buffer *eb; eb = find_extent_buffer(fs_info, search); if (eb) { free_extent_buffer(eb); return; } } target = search; nritems = btrfs_header_nritems(node); nr = slot; while (1) { if (path->reada == READA_BACK) { if (nr == 0) break; nr--; } else if (path->reada == READA_FORWARD || path->reada == READA_FORWARD_ALWAYS) { nr++; if (nr >= nritems) break; } if (path->reada == READA_BACK && objectid) { btrfs_node_key(node, &disk_key, nr); if (btrfs_disk_key_objectid(&disk_key) != objectid) break; } search = btrfs_node_blockptr(node, nr); if (path->reada == READA_FORWARD_ALWAYS || (search <= target && target - search <= 65536) || (search > target && search - target <= 65536)) { btrfs_readahead_node_child(node, nr); nread += blocksize; } nscan++; if (nread > nread_max || nscan > 32) break; } } static noinline void reada_for_balance(struct btrfs_path *path, int level) { struct extent_buffer *parent; int slot; int nritems; parent = path->nodes[level + 1]; if (!parent) return; nritems = btrfs_header_nritems(parent); slot = path->slots[level + 1]; if (slot > 0) btrfs_readahead_node_child(parent, slot - 1); if (slot + 1 < nritems) btrfs_readahead_node_child(parent, slot + 1); } /* * when we walk down the tree, it is usually safe to unlock the higher layers * in the tree. The exceptions are when our path goes through slot 0, because * operations on the tree might require changing key pointers higher up in the * tree. * * callers might also have set path->keep_locks, which tells this code to keep * the lock if the path points to the last slot in the block. This is part of * walking through the tree, and selecting the next slot in the higher block. * * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so * if lowest_unlock is 1, level 0 won't be unlocked */ static noinline void unlock_up(struct btrfs_path *path, int level, int lowest_unlock, int min_write_lock_level, int *write_lock_level) { int i; int skip_level = level; bool check_skip = true; for (i = level; i < BTRFS_MAX_LEVEL; i++) { if (!path->nodes[i]) break; if (!path->locks[i]) break; if (check_skip) { if (path->slots[i] == 0) { skip_level = i + 1; continue; } if (path->keep_locks) { u32 nritems; nritems = btrfs_header_nritems(path->nodes[i]); if (nritems < 1 || path->slots[i] >= nritems - 1) { skip_level = i + 1; continue; } } } if (i >= lowest_unlock && i > skip_level) { check_skip = false; btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]); path->locks[i] = 0; if (write_lock_level && i > min_write_lock_level && i <= *write_lock_level) { *write_lock_level = i - 1; } } } } /* * Helper function for btrfs_search_slot() and other functions that do a search * on a btree. The goal is to find a tree block in the cache (the radix tree at * fs_info->buffer_radix), but if we can't find it, or it's not up to date, read * its pages from disk. * * Returns -EAGAIN, with the path unlocked, if the caller needs to repeat the * whole btree search, starting again from the current root node. */ static int read_block_for_search(struct btrfs_root *root, struct btrfs_path *p, struct extent_buffer **eb_ret, int level, int slot, const struct btrfs_key *key) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_tree_parent_check check = { 0 }; u64 blocknr; u64 gen; struct extent_buffer *tmp; int ret; int parent_level; bool unlock_up; unlock_up = ((level + 1 < BTRFS_MAX_LEVEL) && p->locks[level + 1]); blocknr = btrfs_node_blockptr(*eb_ret, slot); gen = btrfs_node_ptr_generation(*eb_ret, slot); parent_level = btrfs_header_level(*eb_ret); btrfs_node_key_to_cpu(*eb_ret, &check.first_key, slot); check.has_first_key = true; check.level = parent_level - 1; check.transid = gen; check.owner_root = root->root_key.objectid; /* * If we need to read an extent buffer from disk and we are holding locks * on upper level nodes, we unlock all the upper nodes before reading the * extent buffer, and then return -EAGAIN to the caller as it needs to * restart the search. We don't release the lock on the current level * because we need to walk this node to figure out which blocks to read. */ tmp = find_extent_buffer(fs_info, blocknr); if (tmp) { if (p->reada == READA_FORWARD_ALWAYS) reada_for_search(fs_info, p, level, slot, key->objectid); /* first we do an atomic uptodate check */ if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) { /* * Do extra check for first_key, eb can be stale due to * being cached, read from scrub, or have multiple * parents (shared tree blocks). */ if (btrfs_verify_level_key(tmp, parent_level - 1, &check.first_key, gen)) { free_extent_buffer(tmp); return -EUCLEAN; } *eb_ret = tmp; return 0; } if (p->nowait) { free_extent_buffer(tmp); return -EAGAIN; } if (unlock_up) btrfs_unlock_up_safe(p, level + 1); /* now we're allowed to do a blocking uptodate check */ ret = btrfs_read_extent_buffer(tmp, &check); if (ret) { free_extent_buffer(tmp); btrfs_release_path(p); return -EIO; } if (btrfs_check_eb_owner(tmp, root->root_key.objectid)) { free_extent_buffer(tmp); btrfs_release_path(p); return -EUCLEAN; } if (unlock_up) ret = -EAGAIN; goto out; } else if (p->nowait) { return -EAGAIN; } if (unlock_up) { btrfs_unlock_up_safe(p, level + 1); ret = -EAGAIN; } else { ret = 0; } if (p->reada != READA_NONE) reada_for_search(fs_info, p, level, slot, key->objectid); tmp = read_tree_block(fs_info, blocknr, &check); if (IS_ERR(tmp)) { btrfs_release_path(p); return PTR_ERR(tmp); } /* * If the read above didn't mark this buffer up to date, * it will never end up being up to date. Set ret to EIO now * and give up so that our caller doesn't loop forever * on our EAGAINs. */ if (!extent_buffer_uptodate(tmp)) ret = -EIO; out: if (ret == 0) { *eb_ret = tmp; } else { free_extent_buffer(tmp); btrfs_release_path(p); } return ret; } /* * helper function for btrfs_search_slot. This does all of the checks * for node-level blocks and does any balancing required based on * the ins_len. * * If no extra work was required, zero is returned. If we had to * drop the path, -EAGAIN is returned and btrfs_search_slot must * start over */ static int setup_nodes_for_search(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *p, struct extent_buffer *b, int level, int ins_len, int *write_lock_level) { struct btrfs_fs_info *fs_info = root->fs_info; int ret = 0; if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) { if (*write_lock_level < level + 1) { *write_lock_level = level + 1; btrfs_release_path(p); return -EAGAIN; } reada_for_balance(p, level); ret = split_node(trans, root, p, level); b = p->nodes[level]; } else if (ins_len < 0 && btrfs_header_nritems(b) < BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 2) { if (*write_lock_level < level + 1) { *write_lock_level = level + 1; btrfs_release_path(p); return -EAGAIN; } reada_for_balance(p, level); ret = balance_level(trans, root, p, level); if (ret) return ret; b = p->nodes[level]; if (!b) { btrfs_release_path(p); return -EAGAIN; } BUG_ON(btrfs_header_nritems(b) == 1); } return ret; } int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path, u64 iobjectid, u64 ioff, u8 key_type, struct btrfs_key *found_key) { int ret; struct btrfs_key key; struct extent_buffer *eb; ASSERT(path); ASSERT(found_key); key.type = key_type; key.objectid = iobjectid; key.offset = ioff; ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); if (ret < 0) return ret; eb = path->nodes[0]; if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { ret = btrfs_next_leaf(fs_root, path); if (ret) return ret; eb = path->nodes[0]; } btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); if (found_key->type != key.type || found_key->objectid != key.objectid) return 1; return 0; } static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root, struct btrfs_path *p, int write_lock_level) { struct extent_buffer *b; int root_lock = 0; int level = 0; if (p->search_commit_root) { b = root->commit_root; atomic_inc(&b->refs); level = btrfs_header_level(b); /* * Ensure that all callers have set skip_locking when * p->search_commit_root = 1. */ ASSERT(p->skip_locking == 1); goto out; } if (p->skip_locking) { b = btrfs_root_node(root); level = btrfs_header_level(b); goto out; } /* We try very hard to do read locks on the root */ root_lock = BTRFS_READ_LOCK; /* * If the level is set to maximum, we can skip trying to get the read * lock. */ if (write_lock_level < BTRFS_MAX_LEVEL) { /* * We don't know the level of the root node until we actually * have it read locked */ if (p->nowait) { b = btrfs_try_read_lock_root_node(root); if (IS_ERR(b)) return b; } else { b = btrfs_read_lock_root_node(root); } level = btrfs_header_level(b); if (level > write_lock_level) goto out; /* Whoops, must trade for write lock */ btrfs_tree_read_unlock(b); free_extent_buffer(b); } b = btrfs_lock_root_node(root); root_lock = BTRFS_WRITE_LOCK; /* The level might have changed, check again */ level = btrfs_header_level(b); out: /* * The root may have failed to write out at some point, and thus is no * longer valid, return an error in this case. */ if (!extent_buffer_uptodate(b)) { if (root_lock) btrfs_tree_unlock_rw(b, root_lock); free_extent_buffer(b); return ERR_PTR(-EIO); } p->nodes[level] = b; if (!p->skip_locking) p->locks[level] = root_lock; /* * Callers are responsible for dropping b's references. */ return b; } /* * Replace the extent buffer at the lowest level of the path with a cloned * version. The purpose is to be able to use it safely, after releasing the * commit root semaphore, even if relocation is happening in parallel, the * transaction used for relocation is committed and the extent buffer is * reallocated in the next transaction. * * This is used in a context where the caller does not prevent transaction * commits from happening, either by holding a transaction handle or holding * some lock, while it's doing searches through a commit root. * At the moment it's only used for send operations. */ static int finish_need_commit_sem_search(struct btrfs_path *path) { const int i = path->lowest_level; const int slot = path->slots[i]; struct extent_buffer *lowest = path->nodes[i]; struct extent_buffer *clone; ASSERT(path->need_commit_sem); if (!lowest) return 0; lockdep_assert_held_read(&lowest->fs_info->commit_root_sem); clone = btrfs_clone_extent_buffer(lowest); if (!clone) return -ENOMEM; btrfs_release_path(path); path->nodes[i] = clone; path->slots[i] = slot; return 0; } static inline int search_for_key_slot(struct extent_buffer *eb, int search_low_slot, const struct btrfs_key *key, int prev_cmp, int *slot) { /* * If a previous call to btrfs_bin_search() on a parent node returned an * exact match (prev_cmp == 0), we can safely assume the target key will * always be at slot 0 on lower levels, since each key pointer * (struct btrfs_key_ptr) refers to the lowest key accessible from the * subtree it points to. Thus we can skip searching lower levels. */ if (prev_cmp == 0) { *slot = 0; return 0; } return btrfs_bin_search(eb, search_low_slot, key, slot); } static int search_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root, const struct btrfs_key *key, struct btrfs_path *path, int ins_len, int prev_cmp) { struct extent_buffer *leaf = path->nodes[0]; int leaf_free_space = -1; int search_low_slot = 0; int ret; bool do_bin_search = true; /* * If we are doing an insertion, the leaf has enough free space and the * destination slot for the key is not slot 0, then we can unlock our * write lock on the parent, and any other upper nodes, before doing the * binary search on the leaf (with search_for_key_slot()), allowing other * tasks to lock the parent and any other upper nodes. */ if (ins_len > 0) { /* * Cache the leaf free space, since we will need it later and it * will not change until then. */ leaf_free_space = btrfs_leaf_free_space(leaf); /* * !path->locks[1] means we have a single node tree, the leaf is * the root of the tree. */ if (path->locks[1] && leaf_free_space >= ins_len) { struct btrfs_disk_key first_key; ASSERT(btrfs_header_nritems(leaf) > 0); btrfs_item_key(leaf, &first_key, 0); /* * Doing the extra comparison with the first key is cheap, * taking into account that the first key is very likely * already in a cache line because it immediately follows * the extent buffer's header and we have recently accessed * the header's level field. */ ret = btrfs_comp_keys(&first_key, key); if (ret < 0) { /* * The first key is smaller than the key we want * to insert, so we are safe to unlock all upper * nodes and we have to do the binary search. * * We do use btrfs_unlock_up_safe() and not * unlock_up() because the later does not unlock * nodes with a slot of 0 - we can safely unlock * any node even if its slot is 0 since in this * case the key does not end up at slot 0 of the * leaf and there's no need to split the leaf. */ btrfs_unlock_up_safe(path, 1); search_low_slot = 1; } else { /* * The first key is >= then the key we want to * insert, so we can skip the binary search as * the target key will be at slot 0. * * We can not unlock upper nodes when the key is * less than the first key, because we will need * to update the key at slot 0 of the parent node * and possibly of other upper nodes too. * If the key matches the first key, then we can * unlock all the upper nodes, using * btrfs_unlock_up_safe() instead of unlock_up() * as stated above. */ if (ret == 0) btrfs_unlock_up_safe(path, 1); /* * ret is already 0 or 1, matching the result of * a btrfs_bin_search() call, so there is no need * to adjust it. */ do_bin_search = false; path->slots[0] = 0; } } } if (do_bin_search) { ret = search_for_key_slot(leaf, search_low_slot, key, prev_cmp, &path->slots[0]); if (ret < 0) return ret; } if (ins_len > 0) { /* * Item key already exists. In this case, if we are allowed to * insert the item (for example, in dir_item case, item key * collision is allowed), it will be merged with the original * item. Only the item size grows, no new btrfs item will be * added. If search_for_extension is not set, ins_len already * accounts the size btrfs_item, deduct it here so leaf space * check will be correct. */ if (ret == 0 && !path->search_for_extension) { ASSERT(ins_len >= sizeof(struct btrfs_item)); ins_len -= sizeof(struct btrfs_item); } ASSERT(leaf_free_space >= 0); if (leaf_free_space < ins_len) { int err; err = split_leaf(trans, root, key, path, ins_len, (ret == 0)); ASSERT(err <= 0); if (WARN_ON(err > 0)) err = -EUCLEAN; if (err) ret = err; } } return ret; } /* * Look for a key in a tree and perform necessary modifications to preserve * tree invariants. * * @trans: Handle of transaction, used when modifying the tree * @p: Holds all btree nodes along the search path * @root: The root node of the tree * @key: The key we are looking for * @ins_len: Indicates purpose of search: * >0 for inserts it's size of item inserted (*) * <0 for deletions * 0 for plain searches, not modifying the tree * * (*) If size of item inserted doesn't include * sizeof(struct btrfs_item), then p->search_for_extension must * be set. * @cow: boolean should CoW operations be performed. Must always be 1 * when modifying the tree. * * If @ins_len > 0, nodes and leaves will be split as we walk down the tree. * If @ins_len < 0, nodes will be merged as we walk down the tree (if possible) * * If @key is found, 0 is returned and you can find the item in the leaf level * of the path (level 0) * * If @key isn't found, 1 is returned and the leaf level of the path (level 0) * points to the slot where it should be inserted * * If an error is encountered while searching the tree a negative error number * is returned */ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root, const struct btrfs_key *key, struct btrfs_path *p, int ins_len, int cow) { struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *b; int slot; int ret; int err; int level; int lowest_unlock = 1; /* everything at write_lock_level or lower must be write locked */ int write_lock_level = 0; u8 lowest_level = 0; int min_write_lock_level; int prev_cmp; might_sleep(); lowest_level = p->lowest_level; WARN_ON(lowest_level && ins_len > 0); WARN_ON(p->nodes[0] != NULL); BUG_ON(!cow && ins_len); /* * For now only allow nowait for read only operations. There's no * strict reason why we can't, we just only need it for reads so it's * only implemented for reads. */ ASSERT(!p->nowait || !cow); if (ins_len < 0) { lowest_unlock = 2; /* when we are removing items, we might have to go up to level * two as we update tree pointers Make sure we keep write * for those levels as well */ write_lock_level = 2; } else if (ins_len > 0) { /* * for inserting items, make sure we have a write lock on * level 1 so we can update keys */ write_lock_level = 1; } if (!cow) write_lock_level = -1; if (cow && (p->keep_locks || p->lowest_level)) write_lock_level = BTRFS_MAX_LEVEL; min_write_lock_level = write_lock_level; if (p->need_commit_sem) { ASSERT(p->search_commit_root); if (p->nowait) { if (!down_read_trylock(&fs_info->commit_root_sem)) return -EAGAIN; } else { down_read(&fs_info->commit_root_sem); } } again: prev_cmp = -1; b = btrfs_search_slot_get_root(root, p, write_lock_level); if (IS_ERR(b)) { ret = PTR_ERR(b); goto done; } while (b) { int dec = 0; level = btrfs_header_level(b); if (cow) { bool last_level = (level == (BTRFS_MAX_LEVEL - 1)); /* * if we don't really need to cow this block * then we don't want to set the path blocking, * so we test it here */ if (!should_cow_block(trans, root, b)) goto cow_done; /* * must have write locks on this node and the * parent */ if (level > write_lock_level || (level + 1 > write_lock_level && level + 1 < BTRFS_MAX_LEVEL && p->nodes[level + 1])) { write_lock_level = level + 1; btrfs_release_path(p); goto again; } if (last_level) err = btrfs_cow_block(trans, root, b, NULL, 0, &b, BTRFS_NESTING_COW); else err = btrfs_cow_block(trans, root, b, p->nodes[level + 1], p->slots[level + 1], &b, BTRFS_NESTING_COW); if (err) { ret = err; goto done; } } cow_done: p->nodes[level] = b; /* * we have a lock on b and as long as we aren't changing * the tree, there is no way to for the items in b to change. * It is safe to drop the lock on our parent before we * go through the expensive btree search on b. * * If we're inserting or deleting (ins_len != 0), then we might * be changing slot zero, which may require changing the parent. * So, we can't drop the lock until after we know which slot * we're operating on. */ if (!ins_len && !p->keep_locks) { int u = level + 1; if (u < BTRFS_MAX_LEVEL && p->locks[u]) { btrfs_tree_unlock_rw(p->nodes[u], p->locks[u]); p->locks[u] = 0; } } if (level == 0) { if (ins_len > 0) ASSERT(write_lock_level >= 1); ret = search_leaf(trans, root, key, p, ins_len, prev_cmp); if (!p->search_for_split) unlock_up(p, level, lowest_unlock, min_write_lock_level, NULL); goto done; } ret = search_for_key_slot(b, 0, key, prev_cmp, &slot); if (ret < 0) goto done; prev_cmp = ret; if (ret && slot > 0) { dec = 1; slot--; } p->slots[level] = slot; err = setup_nodes_for_search(trans, root, p, b, level, ins_len, &write_lock_level); if (err == -EAGAIN) goto again; if (err) { ret = err; goto done; } b = p->nodes[level]; slot = p->slots[level]; /* * Slot 0 is special, if we change the key we have to update * the parent pointer which means we must have a write lock on * the parent */ if (slot == 0 && ins_len && write_lock_level < level + 1) { write_lock_level = level + 1; btrfs_release_path(p); goto again; } unlock_up(p, level, lowest_unlock, min_write_lock_level, &write_lock_level); if (level == lowest_level) { if (dec) p->slots[level]++; goto done; } err = read_block_for_search(root, p, &b, level, slot, key); if (err == -EAGAIN) goto again; if (err) { ret = err; goto done; } if (!p->skip_locking) { level = btrfs_header_level(b); btrfs_maybe_reset_lockdep_class(root, b); if (level <= write_lock_level) { btrfs_tree_lock(b); p->locks[level] = BTRFS_WRITE_LOCK; } else { if (p->nowait) { if (!btrfs_try_tree_read_lock(b)) { free_extent_buffer(b); ret = -EAGAIN; goto done; } } else { btrfs_tree_read_lock(b); } p->locks[level] = BTRFS_READ_LOCK; } p->nodes[level] = b; } } ret = 1; done: if (ret < 0 && !p->skip_release_on_error) btrfs_release_path(p); if (p->need_commit_sem) { int ret2; ret2 = finish_need_commit_sem_search(p); up_read(&fs_info->commit_root_sem); if (ret2) ret = ret2; } return ret; } ALLOW_ERROR_INJECTION(btrfs_search_slot, ERRNO); /* * Like btrfs_search_slot, this looks for a key in the given tree. It uses the * current state of the tree together with the operations recorded in the tree * modification log to search for the key in a previous version of this tree, as * denoted by the time_seq parameter. * * Naturally, there is no support for insert, delete or cow operations. * * The resulting path and return value will be set up as if we called * btrfs_search_slot at that point in time with ins_len and cow both set to 0. */ int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key, struct btrfs_path *p, u64 time_seq) { struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *b; int slot; int ret; int err; int level; int lowest_unlock = 1; u8 lowest_level = 0; lowest_level = p->lowest_level; WARN_ON(p->nodes[0] != NULL); ASSERT(!p->nowait); if (p->search_commit_root) { BUG_ON(time_seq); return btrfs_search_slot(NULL, root, key, p, 0, 0); } again: b = btrfs_get_old_root(root, time_seq); if (!b) { ret = -EIO; goto done; } level = btrfs_header_level(b); p->locks[level] = BTRFS_READ_LOCK; while (b) { int dec = 0; level = btrfs_header_level(b); p->nodes[level] = b; /* * we have a lock on b and as long as we aren't changing * the tree, there is no way to for the items in b to change. * It is safe to drop the lock on our parent before we * go through the expensive btree search on b. */ btrfs_unlock_up_safe(p, level + 1); ret = btrfs_bin_search(b, 0, key, &slot); if (ret < 0) goto done; if (level == 0) { p->slots[level] = slot; unlock_up(p, level, lowest_unlock, 0, NULL); goto done; } if (ret && slot > 0) { dec = 1; slot--; } p->slots[level] = slot; unlock_up(p, level, lowest_unlock, 0, NULL); if (level == lowest_level) { if (dec) p->slots[level]++; goto done; } err = read_block_for_search(root, p, &b, level, slot, key); if (err == -EAGAIN) goto again; if (err) { ret = err; goto done; } level = btrfs_header_level(b); btrfs_tree_read_lock(b); b = btrfs_tree_mod_log_rewind(fs_info, p, b, time_seq); if (!b) { ret = -ENOMEM; goto done; } p->locks[level] = BTRFS_READ_LOCK; p->nodes[level] = b; } ret = 1; done: if (ret < 0) btrfs_release_path(p); return ret; } /* * Search the tree again to find a leaf with smaller keys. * Returns 0 if it found something. * Returns 1 if there are no smaller keys. * Returns < 0 on error. * * This may release the path, and so you may lose any locks held at the * time you call it. */ static int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) { struct btrfs_key key; struct btrfs_key orig_key; struct btrfs_disk_key found_key; int ret; btrfs_item_key_to_cpu(path->nodes[0], &key, 0); orig_key = key; if (key.offset > 0) { key.offset--; } else if (key.type > 0) { key.type--; key.offset = (u64)-1; } else if (key.objectid > 0) { key.objectid--; key.type = (u8)-1; key.offset = (u64)-1; } else { return 1; } btrfs_release_path(path); ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); if (ret <= 0) return ret; /* * Previous key not found. Even if we were at slot 0 of the leaf we had * before releasing the path and calling btrfs_search_slot(), we now may * be in a slot pointing to the same original key - this can happen if * after we released the path, one of more items were moved from a * sibling leaf into the front of the leaf we had due to an insertion * (see push_leaf_right()). * If we hit this case and our slot is > 0 and just decrement the slot * so that the caller does not process the same key again, which may or * may not break the caller, depending on its logic. */ if (path->slots[0] < btrfs_header_nritems(path->nodes[0])) { btrfs_item_key(path->nodes[0], &found_key, path->slots[0]); ret = btrfs_comp_keys(&found_key, &orig_key); if (ret == 0) { if (path->slots[0] > 0) { path->slots[0]--; return 0; } /* * At slot 0, same key as before, it means orig_key is * the lowest, leftmost, key in the tree. We're done. */ return 1; } } btrfs_item_key(path->nodes[0], &found_key, 0); ret = btrfs_comp_keys(&found_key, &key); /* * We might have had an item with the previous key in the tree right * before we released our path. And after we released our path, that * item might have been pushed to the first slot (0) of the leaf we * were holding due to a tree balance. Alternatively, an item with the * previous key can exist as the only element of a leaf (big fat item). * Therefore account for these 2 cases, so that our callers (like * btrfs_previous_item) don't miss an existing item with a key matching * the previous key we computed above. */ if (ret <= 0) return 0; return 1; } /* * helper to use instead of search slot if no exact match is needed but * instead the next or previous item should be returned. * When find_higher is true, the next higher item is returned, the next lower * otherwise. * When return_any and find_higher are both true, and no higher item is found, * return the next lower instead. * When return_any is true and find_higher is false, and no lower item is found, * return the next higher instead. * It returns 0 if any item is found, 1 if none is found (tree empty), and * < 0 on error */ int btrfs_search_slot_for_read(struct btrfs_root *root, const struct btrfs_key *key, struct btrfs_path *p, int find_higher, int return_any) { int ret; struct extent_buffer *leaf; again: ret = btrfs_search_slot(NULL, root, key, p, 0, 0); if (ret <= 0) return ret; /* * a return value of 1 means the path is at the position where the * item should be inserted. Normally this is the next bigger item, * but in case the previous item is the last in a leaf, path points * to the first free slot in the previous leaf, i.e. at an invalid * item. */ leaf = p->nodes[0]; if (find_higher) { if (p->slots[0] >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(root, p); if (ret <= 0) return ret; if (!return_any) return 1; /* * no higher item found, return the next * lower instead */ return_any = 0; find_higher = 0; btrfs_release_path(p); goto again; } } else { if (p->slots[0] == 0) { ret = btrfs_prev_leaf(root, p); if (ret < 0) return ret; if (!ret) { leaf = p->nodes[0]; if (p->slots[0] == btrfs_header_nritems(leaf)) p->slots[0]--; return 0; } if (!return_any) return 1; /* * no lower item found, return the next * higher instead */ return_any = 0; find_higher = 1; btrfs_release_path(p); goto again; } else { --p->slots[0]; } } return 0; } /* * Execute search and call btrfs_previous_item to traverse backwards if the item * was not found. * * Return 0 if found, 1 if not found and < 0 if error. */ int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key, struct btrfs_path *path) { int ret; ret = btrfs_search_slot(NULL, root, key, path, 0, 0); if (ret > 0) ret = btrfs_previous_item(root, path, key->objectid, key->type); if (ret == 0) btrfs_item_key_to_cpu(path->nodes[0], key, path->slots[0]); return ret; } /* * Search for a valid slot for the given path. * * @root: The root node of the tree. * @key: Will contain a valid item if found. * @path: The starting point to validate the slot. * * Return: 0 if the item is valid * 1 if not found * <0 if error. */ int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key, struct btrfs_path *path) { if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { int ret; ret = btrfs_next_leaf(root, path); if (ret) return ret; } btrfs_item_key_to_cpu(path->nodes[0], key, path->slots[0]); return 0; } /* * adjust the pointers going up the tree, starting at level * making sure the right key of each node is points to 'key'. * This is used after shifting pointers to the left, so it stops * fixing up pointers when a given leaf/node is not in slot 0 of the * higher levels * */ static void fixup_low_keys(struct btrfs_trans_handle *trans, struct btrfs_path *path, struct btrfs_disk_key *key, int level) { int i; struct extent_buffer *t; int ret; for (i = level; i < BTRFS_MAX_LEVEL; i++) { int tslot = path->slots[i]; if (!path->nodes[i]) break; t = path->nodes[i]; ret = btrfs_tree_mod_log_insert_key(t, tslot, BTRFS_MOD_LOG_KEY_REPLACE); BUG_ON(ret < 0); btrfs_set_node_key(t, key, tslot); btrfs_mark_buffer_dirty(trans, path->nodes[i]); if (tslot != 0) break; } } /* * update item key. * * This function isn't completely safe. It's the caller's responsibility * that the new key won't break the order */ void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans, struct btrfs_path *path, const struct btrfs_key *new_key) { struct btrfs_fs_info *fs_info = trans->fs_info; struct btrfs_disk_key disk_key; struct extent_buffer *eb; int slot; eb = path->nodes[0]; slot = path->slots[0]; if (slot > 0) { btrfs_item_key(eb, &disk_key, slot - 1); if (unlikely(btrfs_comp_keys(&disk_key, new_key) >= 0)) { btrfs_print_leaf(eb); btrfs_crit(fs_info, "slot %u key (%llu %u %llu) new key (%llu %u %llu)", slot, btrfs_disk_key_objectid(&disk_key), btrfs_disk_key_type(&disk_key), btrfs_disk_key_offset(&disk_key), new_key->objectid, new_key->type, new_key->offset); BUG(); } } if (slot < btrfs_header_nritems(eb) - 1) { btrfs_item_key(eb, &disk_key, slot + 1); if (unlikely(btrfs_comp_keys(&disk_key, new_key) <= 0)) { btrfs_print_leaf(eb); btrfs_crit(fs_info, "slot %u key (%llu %u %llu) new key (%llu %u %llu)", slot, btrfs_disk_key_objectid(&disk_key), btrfs_disk_key_type(&disk_key), btrfs_disk_key_offset(&disk_key), new_key->objectid, new_key->type, new_key->offset); BUG(); } } btrfs_cpu_key_to_disk(&disk_key, new_key); btrfs_set_item_key(eb, &disk_key, slot); btrfs_mark_buffer_dirty(trans, eb); if (slot == 0) fixup_low_keys(trans, path, &disk_key, 1); } /* * Check key order of two sibling extent buffers. * * Return true if something is wrong. * Return false if everything is fine. * * Tree-checker only works inside one tree block, thus the following * corruption can not be detected by tree-checker: * * Leaf @left | Leaf @right * -------------------------------------------------------------- * | 1 | 2 | 3 | 4 | 5 | f6 | | 7 | 8 | * * Key f6 in leaf @left itself is valid, but not valid when the next * key in leaf @right is 7. * This can only be checked at tree block merge time. * And since tree checker has ensured all key order in each tree block * is correct, we only need to bother the last key of @left and the first * key of @right. */ static bool check_sibling_keys(struct extent_buffer *left, struct extent_buffer *right) { struct btrfs_key left_last; struct btrfs_key right_first; int level = btrfs_header_level(left); int nr_left = btrfs_header_nritems(left); int nr_right = btrfs_header_nritems(right); /* No key to check in one of the tree blocks */ if (!nr_left || !nr_right) return false; if (level) { btrfs_node_key_to_cpu(left, &left_last, nr_left - 1); btrfs_node_key_to_cpu(right, &right_first, 0); } else { btrfs_item_key_to_cpu(left, &left_last, nr_left - 1); btrfs_item_key_to_cpu(right, &right_first, 0); } if (unlikely(btrfs_comp_cpu_keys(&left_last, &right_first) >= 0)) { btrfs_crit(left->fs_info, "left extent buffer:"); btrfs_print_tree(left, false); btrfs_crit(left->fs_info, "right extent buffer:"); btrfs_print_tree(right, false); btrfs_crit(left->fs_info, "bad key order, sibling blocks, left last (%llu %u %llu) right first (%llu %u %llu)", left_last.objectid, left_last.type, left_last.offset, right_first.objectid, right_first.type, right_first.offset); return true; } return false; } /* * try to push data from one node into the next node left in the * tree. * * returns 0 if some ptrs were pushed left, < 0 if there was some horrible * error, and > 0 if there was no room in the left hand block. */ static int push_node_left(struct btrfs_trans_handle *trans, struct extent_buffer *dst, struct extent_buffer *src, int empty) { struct btrfs_fs_info *fs_info = trans->fs_info; int push_items = 0; int src_nritems; int dst_nritems; int ret = 0; src_nritems = btrfs_header_nritems(src); dst_nritems = btrfs_header_nritems(dst); push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems; WARN_ON(btrfs_header_generation(src) != trans->transid); WARN_ON(btrfs_header_generation(dst) != trans->transid); if (!empty && src_nritems <= 8) return 1; if (push_items <= 0) return 1; if (empty) { push_items = min(src_nritems, push_items); if (push_items < src_nritems) { /* leave at least 8 pointers in the node if * we aren't going to empty it */ if (src_nritems - push_items < 8) { if (push_items <= 8) return 1; push_items -= 8; } } } else push_items = min(src_nritems - 8, push_items); /* dst is the left eb, src is the middle eb */ if (check_sibling_keys(dst, src)) { ret = -EUCLEAN; btrfs_abort_transaction(trans, ret); return ret; } ret = btrfs_tree_mod_log_eb_copy(dst, src, dst_nritems, 0, push_items); if (ret) { btrfs_abort_transaction(trans, ret); return ret; } copy_extent_buffer(dst, src, btrfs_node_key_ptr_offset(dst, dst_nritems), btrfs_node_key_ptr_offset(src, 0), push_items * sizeof(struct btrfs_key_ptr)); if (push_items < src_nritems) { /* * btrfs_tree_mod_log_eb_copy handles logging the move, so we * don't need to do an explicit tree mod log operation for it. */ memmove_extent_buffer(src, btrfs_node_key_ptr_offset(src, 0), btrfs_node_key_ptr_offset(src, push_items), (src_nritems - push_items) * sizeof(struct btrfs_key_ptr)); } btrfs_set_header_nritems(src, src_nritems - push_items); btrfs_set_header_nritems(dst, dst_nritems + push_items); btrfs_mark_buffer_dirty(trans, src); btrfs_mark_buffer_dirty(trans, dst); return ret; } /* * try to push data from one node into the next node right in the * tree. * * returns 0 if some ptrs were pushed, < 0 if there was some horrible * error, and > 0 if there was no room in the right hand block. * * this will only push up to 1/2 the contents of the left node over */ static int balance_node_right(struct btrfs_trans_handle *trans, struct extent_buffer *dst, struct extent_buffer *src) { struct btrfs_fs_info *fs_info = trans->fs_info; int push_items = 0; int max_push; int src_nritems; int dst_nritems; int ret = 0; WARN_ON(btrfs_header_generation(src) != trans->transid); WARN_ON(btrfs_header_generation(dst) != trans->transid); src_nritems = btrfs_header_nritems(src); dst_nritems = btrfs_header_nritems(dst); push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems; if (push_items <= 0) return 1; if (src_nritems < 4) return 1; max_push = src_nritems / 2 + 1; /* don't try to empty the node */ if (max_push >= src_nritems) return 1; if (max_push < push_items) push_items = max_push; /* dst is the right eb, src is the middle eb */ if (check_sibling_keys(src, dst)) { ret = -EUCLEAN; btrfs_abort_transaction(trans, ret); return ret; } /* * btrfs_tree_mod_log_eb_copy handles logging the move, so we don't * need to do an explicit tree mod log operation for it. */ memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(dst, push_items), btrfs_node_key_ptr_offset(dst, 0), (dst_nritems) * sizeof(struct btrfs_key_ptr)); ret = btrfs_tree_mod_log_eb_copy(dst, src, 0, src_nritems - push_items, push_items); if (ret) { btrfs_abort_transaction(trans, ret); return ret; } copy_extent_buffer(dst, src, btrfs_node_key_ptr_offset(dst, 0), btrfs_node_key_ptr_offset(src, src_nritems - push_items), push_items * sizeof(struct btrfs_key_ptr)); btrfs_set_header_nritems(src, src_nritems - push_items); btrfs_set_header_nritems(dst, dst_nritems + push_items); btrfs_mark_buffer_dirty(trans, src); btrfs_mark_buffer_dirty(trans, dst); return ret; } /* * helper function to insert a new root level in the tree. * A new node is allocated, and a single item is inserted to * point to the existing root * * returns zero on success or < 0 on failure. */ static noinline int insert_new_root(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int level) { u64 lower_gen; struct extent_buffer *lower; struct extent_buffer *c; struct extent_buffer *old; struct btrfs_disk_key lower_key; int ret; BUG_ON(path->nodes[level]); BUG_ON(path->nodes[level-1] != root->node); lower = path->nodes[level-1]; if (level == 1) btrfs_item_key(lower, &lower_key, 0); else btrfs_node_key(lower, &lower_key, 0); c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, &lower_key, level, root->node->start, 0, 0, BTRFS_NESTING_NEW_ROOT); if (IS_ERR(c)) return PTR_ERR(c); root_add_used_bytes(root); btrfs_set_header_nritems(c, 1); btrfs_set_node_key(c, &lower_key, 0); btrfs_set_node_blockptr(c, 0, lower->start); lower_gen = btrfs_header_generation(lower); WARN_ON(lower_gen != trans->transid); btrfs_set_node_ptr_generation(c, 0, lower_gen); btrfs_mark_buffer_dirty(trans, c); old = root->node; ret = btrfs_tree_mod_log_insert_root(root->node, c, false); if (ret < 0) { btrfs_free_tree_block(trans, btrfs_root_id(root), c, 0, 1); btrfs_tree_unlock(c); free_extent_buffer(c); return ret; } rcu_assign_pointer(root->node, c); /* the super has an extra ref to root->node */ free_extent_buffer(old); add_root_to_dirty_list(root); atomic_inc(&c->refs); path->nodes[level] = c; path->locks[level] = BTRFS_WRITE_LOCK; path->slots[level] = 0; return 0; } /* * worker function to insert a single pointer in a node. * the node should have enough room for the pointer already * * slot and level indicate where you want the key to go, and * blocknr is the block the key points to. */ static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_path *path, struct btrfs_disk_key *key, u64 bytenr, int slot, int level) { struct extent_buffer *lower; int nritems; int ret; BUG_ON(!path->nodes[level]); btrfs_assert_tree_write_locked(path->nodes[level]); lower = path->nodes[level]; nritems = btrfs_header_nritems(lower); BUG_ON(slot > nritems); BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(trans->fs_info)); if (slot != nritems) { if (level) { ret = btrfs_tree_mod_log_insert_move(lower, slot + 1, slot, nritems - slot); if (ret < 0) { btrfs_abort_transaction(trans, ret); return ret; } } memmove_extent_buffer(lower, btrfs_node_key_ptr_offset(lower, slot + 1), btrfs_node_key_ptr_offset(lower, slot), (nritems - slot) * sizeof(struct btrfs_key_ptr)); } if (level) { ret = btrfs_tree_mod_log_insert_key(lower, slot, BTRFS_MOD_LOG_KEY_ADD); if (ret < 0) { btrfs_abort_transaction(trans, ret); return ret; } } btrfs_set_node_key(lower, key, slot); btrfs_set_node_blockptr(lower, slot, bytenr); WARN_ON(trans->transid == 0); btrfs_set_node_ptr_generation(lower, slot, trans->transid); btrfs_set_header_nritems(lower, nritems + 1); btrfs_mark_buffer_dirty(trans, lower); return 0; } /* * split the node at the specified level in path in two. * The path is corrected to point to the appropriate node after the split * * Before splitting this tries to make some room in the node by pushing * left and right, if either one works, it returns right away. * * returns 0 on success and < 0 on failure */ static noinline int split_node(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int level) { struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *c; struct extent_buffer *split; struct btrfs_disk_key disk_key; int mid; int ret; u32 c_nritems; c = path->nodes[level]; WARN_ON(btrfs_header_generation(c) != trans->transid); if (c == root->node) { /* * trying to split the root, lets make a new one * * tree mod log: We don't log_removal old root in * insert_new_root, because that root buffer will be kept as a * normal node. We are going to log removal of half of the * elements below with btrfs_tree_mod_log_eb_copy(). We're * holding a tree lock on the buffer, which is why we cannot * race with other tree_mod_log users. */ ret = insert_new_root(trans, root, path, level + 1); if (ret) return ret; } else { ret = push_nodes_for_insert(trans, root, path, level); c = path->nodes[level]; if (!ret && btrfs_header_nritems(c) < BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) return 0; if (ret < 0) return ret; } c_nritems = btrfs_header_nritems(c); mid = (c_nritems + 1) / 2; btrfs_node_key(c, &disk_key, mid); split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, &disk_key, level, c->start, 0, 0, BTRFS_NESTING_SPLIT); if (IS_ERR(split)) return PTR_ERR(split); root_add_used_bytes(root); ASSERT(btrfs_header_level(c) == level); ret = btrfs_tree_mod_log_eb_copy(split, c, 0, mid, c_nritems - mid); if (ret) { btrfs_tree_unlock(split); free_extent_buffer(split); btrfs_abort_transaction(trans, ret); return ret; } copy_extent_buffer(split, c, btrfs_node_key_ptr_offset(split, 0), btrfs_node_key_ptr_offset(c, mid), (c_nritems - mid) * sizeof(struct btrfs_key_ptr)); btrfs_set_header_nritems(split, c_nritems - mid); btrfs_set_header_nritems(c, mid); btrfs_mark_buffer_dirty(trans, c); btrfs_mark_buffer_dirty(trans, split); ret = insert_ptr(trans, path, &disk_key, split->start, path->slots[level + 1] + 1, level + 1); if (ret < 0) { btrfs_tree_unlock(split); free_extent_buffer(split); return ret; } if (path->slots[level] >= mid) { path->slots[level] -= mid; btrfs_tree_unlock(c); free_extent_buffer(c); path->nodes[level] = split; path->slots[level + 1] += 1; } else { btrfs_tree_unlock(split); free_extent_buffer(split); } return 0; } /* * how many bytes are required to store the items in a leaf. start * and nr indicate which items in the leaf to check. This totals up the * space used both by the item structs and the item data */ static int leaf_space_used(const struct extent_buffer *l, int start, int nr) { int data_len; int nritems = btrfs_header_nritems(l); int end = min(nritems, start + nr) - 1; if (!nr) return 0; data_len = btrfs_item_offset(l, start) + btrfs_item_size(l, start); data_len = data_len - btrfs_item_offset(l, end); data_len += sizeof(struct btrfs_item) * nr; WARN_ON(data_len < 0); return data_len; } /* * The space between the end of the leaf items and * the start of the leaf data. IOW, how much room * the leaf has left for both items and data */ int btrfs_leaf_free_space(const struct extent_buffer *leaf) { struct btrfs_fs_info *fs_info = leaf->fs_info; int nritems = btrfs_header_nritems(leaf); int ret; ret = BTRFS_LEAF_DATA_SIZE(fs_info) - leaf_space_used(leaf, 0, nritems); if (ret < 0) { btrfs_crit(fs_info, "leaf free space ret %d, leaf data size %lu, used %d nritems %d", ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(fs_info), leaf_space_used(leaf, 0, nritems), nritems); } return ret; } /* * min slot controls the lowest index we're willing to push to the * right. We'll push up to and including min_slot, but no lower */ static noinline int __push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_path *path, int data_size, int empty, struct extent_buffer *right, int free_space, u32 left_nritems, u32 min_slot) { struct btrfs_fs_info *fs_info = right->fs_info; struct extent_buffer *left = path->nodes[0]; struct extent_buffer *upper = path->nodes[1]; struct btrfs_map_token token; struct btrfs_disk_key disk_key; int slot; u32 i; int push_space = 0; int push_items = 0; u32 nr; u32 right_nritems; u32 data_end; u32 this_item_size; if (empty) nr = 0; else nr = max_t(u32, 1, min_slot); if (path->slots[0] >= left_nritems) push_space += data_size; slot = path->slots[1]; i = left_nritems - 1; while (i >= nr) { if (!empty && push_items > 0) { if (path->slots[0] > i) break; if (path->slots[0] == i) { int space = btrfs_leaf_free_space(left); if (space + push_space * 2 > free_space) break; } } if (path->slots[0] == i) push_space += data_size; this_item_size = btrfs_item_size(left, i); if (this_item_size + sizeof(struct btrfs_item) + push_space > free_space) break; push_items++; push_space += this_item_size + sizeof(struct btrfs_item); if (i == 0) break; i--; } if (push_items == 0) goto out_unlock; WARN_ON(!empty && push_items == left_nritems); /* push left to right */ right_nritems = btrfs_header_nritems(right); push_space = btrfs_item_data_end(left, left_nritems - push_items); push_space -= leaf_data_end(left); /* make room in the right data area */ data_end = leaf_data_end(right); memmove_leaf_data(right, data_end - push_space, data_end, BTRFS_LEAF_DATA_SIZE(fs_info) - data_end); /* copy from the left data area */ copy_leaf_data(right, left, BTRFS_LEAF_DATA_SIZE(fs_info) - push_space, leaf_data_end(left), push_space); memmove_leaf_items(right, push_items, 0, right_nritems); /* copy the items from left to right */ copy_leaf_items(right, left, 0, left_nritems - push_items, push_items); /* update the item pointers */ btrfs_init_map_token(&token, right); right_nritems += push_items; btrfs_set_header_nritems(right, right_nritems); push_space = BTRFS_LEAF_DATA_SIZE(fs_info); for (i = 0; i < right_nritems; i++) { push_space -= btrfs_token_item_size(&token, i); btrfs_set_token_item_offset(&token, i, push_space); } left_nritems -= push_items; btrfs_set_header_nritems(left, left_nritems); if (left_nritems) btrfs_mark_buffer_dirty(trans, left); else btrfs_clear_buffer_dirty(trans, left); btrfs_mark_buffer_dirty(trans, right); btrfs_item_key(right, &disk_key, 0); btrfs_set_node_key(upper, &disk_key, slot + 1); btrfs_mark_buffer_dirty(trans, upper); /* then fixup the leaf pointer in the path */ if (path->slots[0] >= left_nritems) { path->slots[0] -= left_nritems; if (btrfs_header_nritems(path->nodes[0]) == 0) btrfs_clear_buffer_dirty(trans, path->nodes[0]); btrfs_tree_unlock(path->nodes[0]); free_extent_buffer(path->nodes[0]); path->nodes[0] = right; path->slots[1] += 1; } else { btrfs_tree_unlock(right); free_extent_buffer(right); } return 0; out_unlock: btrfs_tree_unlock(right); free_extent_buffer(right); return 1; } /* * push some data in the path leaf to the right, trying to free up at * least data_size bytes. returns zero if the push worked, nonzero otherwise * * returns 1 if the push failed because the other node didn't have enough * room, 0 if everything worked out and < 0 if there were major errors. * * this will push starting from min_slot to the end of the leaf. It won't * push any slot lower than min_slot */ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int min_data_size, int data_size, int empty, u32 min_slot) { struct extent_buffer *left = path->nodes[0]; struct extent_buffer *right; struct extent_buffer *upper; int slot; int free_space; u32 left_nritems; int ret; if (!path->nodes[1]) return 1; slot = path->slots[1]; upper = path->nodes[1]; if (slot >= btrfs_header_nritems(upper) - 1) return 1; btrfs_assert_tree_write_locked(path->nodes[1]); right = btrfs_read_node_slot(upper, slot + 1); if (IS_ERR(right)) return PTR_ERR(right); __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT); free_space = btrfs_leaf_free_space(right); if (free_space < data_size) goto out_unlock; ret = btrfs_cow_block(trans, root, right, upper, slot + 1, &right, BTRFS_NESTING_RIGHT_COW); if (ret) goto out_unlock; left_nritems = btrfs_header_nritems(left); if (left_nritems == 0) goto out_unlock; if (check_sibling_keys(left, right)) { ret = -EUCLEAN; btrfs_abort_transaction(trans, ret); btrfs_tree_unlock(right); free_extent_buffer(right); return ret; } if (path->slots[0] == left_nritems && !empty) { /* Key greater than all keys in the leaf, right neighbor has * enough room for it and we're not emptying our leaf to delete * it, therefore use right neighbor to insert the new item and * no need to touch/dirty our left leaf. */ btrfs_tree_unlock(left); free_extent_buffer(left); path->nodes[0] = right; path->slots[0] = 0; path->slots[1]++; return 0; } return __push_leaf_right(trans, path, min_data_size, empty, right, free_space, left_nritems, min_slot); out_unlock: btrfs_tree_unlock(right); free_extent_buffer(right); return 1; } /* * push some data in the path leaf to the left, trying to free up at * least data_size bytes. returns zero if the push worked, nonzero otherwise * * max_slot can put a limit on how far into the leaf we'll push items. The * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the * items */ static noinline int __push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_path *path, int data_size, int empty, struct extent_buffer *left, int free_space, u32 right_nritems, u32 max_slot) { struct btrfs_fs_info *fs_info = left->fs_info; struct btrfs_disk_key disk_key; struct extent_buffer *right = path->nodes[0]; int i; int push_space = 0; int push_items = 0; u32 old_left_nritems; u32 nr; int ret = 0; u32 this_item_size; u32 old_left_item_size; struct btrfs_map_token token; if (empty) nr = min(right_nritems, max_slot); else nr = min(right_nritems - 1, max_slot); for (i = 0; i < nr; i++) { if (!empty && push_items > 0) { if (path->slots[0] < i) break; if (path->slots[0] == i) { int space = btrfs_leaf_free_space(right); if (space + push_space * 2 > free_space) break; } } if (path->slots[0] == i) push_space += data_size; this_item_size = btrfs_item_size(right, i); if (this_item_size + sizeof(struct btrfs_item) + push_space > free_space) break; push_items++; push_space += this_item_size + sizeof(struct btrfs_item); } if (push_items == 0) { ret = 1; goto out; } WARN_ON(!empty && push_items == btrfs_header_nritems(right)); /* push data from right to left */ copy_leaf_items(left, right, btrfs_header_nritems(left), 0, push_items); push_space = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_offset(right, push_items - 1); copy_leaf_data(left, right, leaf_data_end(left) - push_space, btrfs_item_offset(right, push_items - 1), push_space); old_left_nritems = btrfs_header_nritems(left); BUG_ON(old_left_nritems <= 0); btrfs_init_map_token(&token, left); old_left_item_size = btrfs_item_offset(left, old_left_nritems - 1); for (i = old_left_nritems; i < old_left_nritems + push_items; i++) { u32 ioff; ioff = btrfs_token_item_offset(&token, i); btrfs_set_token_item_offset(&token, i, ioff - (BTRFS_LEAF_DATA_SIZE(fs_info) - old_left_item_size)); } btrfs_set_header_nritems(left, old_left_nritems + push_items); /* fixup right node */ if (push_items > right_nritems) WARN(1, KERN_CRIT "push items %d nr %u\n", push_items, right_nritems); if (push_items < right_nritems) { push_space = btrfs_item_offset(right, push_items - 1) - leaf_data_end(right); memmove_leaf_data(right, BTRFS_LEAF_DATA_SIZE(fs_info) - push_space, leaf_data_end(right), push_space); memmove_leaf_items(right, 0, push_items, btrfs_header_nritems(right) - push_items); } btrfs_init_map_token(&token, right); right_nritems -= push_items; btrfs_set_header_nritems(right, right_nritems); push_space = BTRFS_LEAF_DATA_SIZE(fs_info); for (i = 0; i < right_nritems; i++) { push_space = push_space - btrfs_token_item_size(&token, i); btrfs_set_token_item_offset(&token, i, push_space); } btrfs_mark_buffer_dirty(trans, left); if (right_nritems) btrfs_mark_buffer_dirty(trans, right); else btrfs_clear_buffer_dirty(trans, right); btrfs_item_key(right, &disk_key, 0); fixup_low_keys(trans, path, &disk_key, 1); /* then fixup the leaf pointer in the path */ if (path->slots[0] < push_items) { path->slots[0] += old_left_nritems; btrfs_tree_unlock(path->nodes[0]); free_extent_buffer(path->nodes[0]); path->nodes[0] = left; path->slots[1] -= 1; } else { btrfs_tree_unlock(left); free_extent_buffer(left); path->slots[0] -= push_items; } BUG_ON(path->slots[0] < 0); return ret; out: btrfs_tree_unlock(left); free_extent_buffer(left); return ret; } /* * push some data in the path leaf to the left, trying to free up at * least data_size bytes. returns zero if the push worked, nonzero otherwise * * max_slot can put a limit on how far into the leaf we'll push items. The * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the * items */ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int min_data_size, int data_size, int empty, u32 max_slot) { struct extent_buffer *right = path->nodes[0]; struct extent_buffer *left; int slot; int free_space; u32 right_nritems; int ret = 0; slot = path->slots[1]; if (slot == 0) return 1; if (!path->nodes[1]) return 1; right_nritems = btrfs_header_nritems(right); if (right_nritems == 0) return 1; btrfs_assert_tree_write_locked(path->nodes[1]); left = btrfs_read_node_slot(path->nodes[1], slot - 1); if (IS_ERR(left)) return PTR_ERR(left); __btrfs_tree_lock(left, BTRFS_NESTING_LEFT); free_space = btrfs_leaf_free_space(left); if (free_space < data_size) { ret = 1; goto out; } ret = btrfs_cow_block(trans, root, left, path->nodes[1], slot - 1, &left, BTRFS_NESTING_LEFT_COW); if (ret) { /* we hit -ENOSPC, but it isn't fatal here */ if (ret == -ENOSPC) ret = 1; goto out; } if (check_sibling_keys(left, right)) { ret = -EUCLEAN; btrfs_abort_transaction(trans, ret); goto out; } return __push_leaf_left(trans, path, min_data_size, empty, left, free_space, right_nritems, max_slot); out: btrfs_tree_unlock(left); free_extent_buffer(left); return ret; } /* * split the path's leaf in two, making sure there is at least data_size * available for the resulting leaf level of the path. */ static noinline int copy_for_split(struct btrfs_trans_handle *trans, struct btrfs_path *path, struct extent_buffer *l, struct extent_buffer *right, int slot, int mid, int nritems) { struct btrfs_fs_info *fs_info = trans->fs_info; int data_copy_size; int rt_data_off; int i; int ret; struct btrfs_disk_key disk_key; struct btrfs_map_token token; nritems = nritems - mid; btrfs_set_header_nritems(right, nritems); data_copy_size = btrfs_item_data_end(l, mid) - leaf_data_end(l); copy_leaf_items(right, l, 0, mid, nritems); copy_leaf_data(right, l, BTRFS_LEAF_DATA_SIZE(fs_info) - data_copy_size, leaf_data_end(l), data_copy_size); rt_data_off = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_data_end(l, mid); btrfs_init_map_token(&token, right); for (i = 0; i < nritems; i++) { u32 ioff; ioff = btrfs_token_item_offset(&token, i); btrfs_set_token_item_offset(&token, i, ioff + rt_data_off); } btrfs_set_header_nritems(l, mid); btrfs_item_key(right, &disk_key, 0); ret = insert_ptr(trans, path, &disk_key, right->start, path->slots[1] + 1, 1); if (ret < 0) return ret; btrfs_mark_buffer_dirty(trans, right); btrfs_mark_buffer_dirty(trans, l); BUG_ON(path->slots[0] != slot); if (mid <= slot) { btrfs_tree_unlock(path->nodes[0]); free_extent_buffer(path->nodes[0]); path->nodes[0] = right; path->slots[0] -= mid; path->slots[1] += 1; } else { btrfs_tree_unlock(right); free_extent_buffer(right); } BUG_ON(path->slots[0] < 0); return 0; } /* * double splits happen when we need to insert a big item in the middle * of a leaf. A double split can leave us with 3 mostly empty leaves: * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ] * A B C * * We avoid this by trying to push the items on either side of our target * into the adjacent leaves. If all goes well we can avoid the double split * completely. */ static noinline int push_for_double_split(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int data_size) { int ret; int progress = 0; int slot; u32 nritems; int space_needed = data_size; slot = path->slots[0]; if (slot < btrfs_header_nritems(path->nodes[0])) space_needed -= btrfs_leaf_free_space(path->nodes[0]); /* * try to push all the items after our slot into the * right leaf */ ret = push_leaf_right(trans, root, path, 1, space_needed, 0, slot); if (ret < 0) return ret; if (ret == 0) progress++; nritems = btrfs_header_nritems(path->nodes[0]); /* * our goal is to get our slot at the start or end of a leaf. If * we've done so we're done */ if (path->slots[0] == 0 || path->slots[0] == nritems) return 0; if (btrfs_leaf_free_space(path->nodes[0]) >= data_size) return 0; /* try to push all the items before our slot into the next leaf */ slot = path->slots[0]; space_needed = data_size; if (slot > 0) space_needed -= btrfs_leaf_free_space(path->nodes[0]); ret = push_leaf_left(trans, root, path, 1, space_needed, 0, slot); if (ret < 0) return ret; if (ret == 0) progress++; if (progress) return 0; return 1; } /* * split the path's leaf in two, making sure there is at least data_size * available for the resulting leaf level of the path. * * returns 0 if all went well and < 0 on failure. */ static noinline int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root, const struct btrfs_key *ins_key, struct btrfs_path *path, int data_size, int extend) { struct btrfs_disk_key disk_key; struct extent_buffer *l; u32 nritems; int mid; int slot; struct extent_buffer *right; struct btrfs_fs_info *fs_info = root->fs_info; int ret = 0; int wret; int split; int num_doubles = 0; int tried_avoid_double = 0; l = path->nodes[0]; slot = path->slots[0]; if (extend && data_size + btrfs_item_size(l, slot) + sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(fs_info)) return -EOVERFLOW; /* first try to make some room by pushing left and right */ if (data_size && path->nodes[1]) { int space_needed = data_size; if (slot < btrfs_header_nritems(l)) space_needed -= btrfs_leaf_free_space(l); wret = push_leaf_right(trans, root, path, space_needed, space_needed, 0, 0); if (wret < 0) return wret; if (wret) { space_needed = data_size; if (slot > 0) space_needed -= btrfs_leaf_free_space(l); wret = push_leaf_left(trans, root, path, space_needed, space_needed, 0, (u32)-1); if (wret < 0) return wret; } l = path->nodes[0]; /* did the pushes work? */ if (btrfs_leaf_free_space(l) >= data_size) return 0; } if (!path->nodes[1]) { ret = insert_new_root(trans, root, path, 1); if (ret) return ret; } again: split = 1; l = path->nodes[0]; slot = path->slots[0]; nritems = btrfs_header_nritems(l); mid = (nritems + 1) / 2; if (mid <= slot) { if (nritems == 1 || leaf_space_used(l, mid, nritems - mid) + data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) { if (slot >= nritems) { split = 0; } else { mid = slot; if (mid != nritems && leaf_space_used(l, mid, nritems - mid) + data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) { if (data_size && !tried_avoid_double) goto push_for_double; split = 2; } } } } else { if (leaf_space_used(l, 0, mid) + data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) { if (!extend && data_size && slot == 0) { split = 0; } else if ((extend || !data_size) && slot == 0) { mid = 1; } else { mid = slot; if (mid != nritems && leaf_space_used(l, mid, nritems - mid) + data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) { if (data_size && !tried_avoid_double) goto push_for_double; split = 2; } } } } if (split == 0) btrfs_cpu_key_to_disk(&disk_key, ins_key); else btrfs_item_key(l, &disk_key, mid); /* * We have to about BTRFS_NESTING_NEW_ROOT here if we've done a double * split, because we're only allowed to have MAX_LOCKDEP_SUBCLASSES * subclasses, which is 8 at the time of this patch, and we've maxed it * out. In the future we could add a * BTRFS_NESTING_SPLIT_THE_SPLITTENING if we need to, but for now just * use BTRFS_NESTING_NEW_ROOT. */ right = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, &disk_key, 0, l->start, 0, 0, num_doubles ? BTRFS_NESTING_NEW_ROOT : BTRFS_NESTING_SPLIT); if (IS_ERR(right)) return PTR_ERR(right); root_add_used_bytes(root); if (split == 0) { if (mid <= slot) { btrfs_set_header_nritems(right, 0); ret = insert_ptr(trans, path, &disk_key, right->start, path->slots[1] + 1, 1); if (ret < 0) { btrfs_tree_unlock(right); free_extent_buffer(right); return ret; } btrfs_tree_unlock(path->nodes[0]); free_extent_buffer(path->nodes[0]); path->nodes[0] = right; path->slots[0] = 0; path->slots[1] += 1; } else { btrfs_set_header_nritems(right, 0); ret = insert_ptr(trans, path, &disk_key, right->start, path->slots[1], 1); if (ret < 0) { btrfs_tree_unlock(right); free_extent_buffer(right); return ret; } btrfs_tree_unlock(path->nodes[0]); free_extent_buffer(path->nodes[0]); path->nodes[0] = right; path->slots[0] = 0; if (path->slots[1] == 0) fixup_low_keys(trans, path, &disk_key, 1); } /* * We create a new leaf 'right' for the required ins_len and * we'll do btrfs_mark_buffer_dirty() on this leaf after copying * the content of ins_len to 'right'. */ return ret; } ret = copy_for_split(trans, path, l, right, slot, mid, nritems); if (ret < 0) { btrfs_tree_unlock(right); free_extent_buffer(right); return ret; } if (split == 2) { BUG_ON(num_doubles != 0); num_doubles++; goto again; } return 0; push_for_double: push_for_double_split(trans, root, path, data_size); tried_avoid_double = 1; if (btrfs_leaf_free_space(path->nodes[0]) >= data_size) return 0; goto again; } static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int ins_len) { struct btrfs_key key; struct extent_buffer *leaf; struct btrfs_file_extent_item *fi; u64 extent_len = 0; u32 item_size; int ret; leaf = path->nodes[0]; btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY && key.type != BTRFS_EXTENT_CSUM_KEY); if (btrfs_leaf_free_space(leaf) >= ins_len) return 0; item_size = btrfs_item_size(leaf, path->slots[0]); if (key.type == BTRFS_EXTENT_DATA_KEY) { fi = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); extent_len = btrfs_file_extent_num_bytes(leaf, fi); } btrfs_release_path(path); path->keep_locks = 1; path->search_for_split = 1; ret = btrfs_search_slot(trans, root, &key, path, 0, 1); path->search_for_split = 0; if (ret > 0) ret = -EAGAIN; if (ret < 0) goto err; ret = -EAGAIN; leaf = path->nodes[0]; /* if our item isn't there, return now */ if (item_size != btrfs_item_size(leaf, path->slots[0])) goto err; /* the leaf has changed, it now has room. return now */ if (btrfs_leaf_free_space(path->nodes[0]) >= ins_len) goto err; if (key.type == BTRFS_EXTENT_DATA_KEY) { fi = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); if (extent_len != btrfs_file_extent_num_bytes(leaf, fi)) goto err; } ret = split_leaf(trans, root, &key, path, ins_len, 1); if (ret) goto err; path->keep_locks = 0; btrfs_unlock_up_safe(path, 1); return 0; err: path->keep_locks = 0; return ret; } static noinline int split_item(struct btrfs_trans_handle *trans, struct btrfs_path *path, const struct btrfs_key *new_key, unsigned long split_offset) { struct extent_buffer *leaf; int orig_slot, slot; char *buf; u32 nritems; u32 item_size; u32 orig_offset; struct btrfs_disk_key disk_key; leaf = path->nodes[0]; /* * Shouldn't happen because the caller must have previously called * setup_leaf_for_split() to make room for the new item in the leaf. */ if (WARN_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item))) return -ENOSPC; orig_slot = path->slots[0]; orig_offset = btrfs_item_offset(leaf, path->slots[0]); item_size = btrfs_item_size(leaf, path->slots[0]); buf = kmalloc(item_size, GFP_NOFS); if (!buf) return -ENOMEM; read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, path->slots[0]), item_size); slot = path->slots[0] + 1; nritems = btrfs_header_nritems(leaf); if (slot != nritems) { /* shift the items */ memmove_leaf_items(leaf, slot + 1, slot, nritems - slot); } btrfs_cpu_key_to_disk(&disk_key, new_key); btrfs_set_item_key(leaf, &disk_key, slot); btrfs_set_item_offset(leaf, slot, orig_offset); btrfs_set_item_size(leaf, slot, item_size - split_offset); btrfs_set_item_offset(leaf, orig_slot, orig_offset + item_size - split_offset); btrfs_set_item_size(leaf, orig_slot, split_offset); btrfs_set_header_nritems(leaf, nritems + 1); /* write the data for the start of the original item */ write_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, path->slots[0]), split_offset); /* write the data for the new item */ write_extent_buffer(leaf, buf + split_offset, btrfs_item_ptr_offset(leaf, slot), item_size - split_offset); btrfs_mark_buffer_dirty(trans, leaf); BUG_ON(btrfs_leaf_free_space(leaf) < 0); kfree(buf); return 0; } /* * This function splits a single item into two items, * giving 'new_key' to the new item and splitting the * old one at split_offset (from the start of the item). * * The path may be released by this operation. After * the split, the path is pointing to the old item. The * new item is going to be in the same node as the old one. * * Note, the item being split must be smaller enough to live alone on * a tree block with room for one extra struct btrfs_item * * This allows us to split the item in place, keeping a lock on the * leaf the entire time. */ int btrfs_split_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, const struct btrfs_key *new_key, unsigned long split_offset) { int ret; ret = setup_leaf_for_split(trans, root, path, sizeof(struct btrfs_item)); if (ret) return ret; ret = split_item(trans, path, new_key, split_offset); return ret; } /* * make the item pointed to by the path smaller. new_size indicates * how small to make it, and from_end tells us if we just chop bytes * off the end of the item or if we shift the item to chop bytes off * the front. */ void btrfs_truncate_item(struct btrfs_trans_handle *trans, struct btrfs_path *path, u32 new_size, int from_end) { int slot; struct extent_buffer *leaf; u32 nritems; unsigned int data_end; unsigned int old_data_start; unsigned int old_size; unsigned int size_diff; int i; struct btrfs_map_token token; leaf = path->nodes[0]; slot = path->slots[0]; old_size = btrfs_item_size(leaf, slot); if (old_size == new_size) return; nritems = btrfs_header_nritems(leaf); data_end = leaf_data_end(leaf); old_data_start = btrfs_item_offset(leaf, slot); size_diff = old_size - new_size; BUG_ON(slot < 0); BUG_ON(slot >= nritems); /* * item0..itemN ... dataN.offset..dataN.size .. data0.size */ /* first correct the data pointers */ btrfs_init_map_token(&token, leaf); for (i = slot; i < nritems; i++) { u32 ioff; ioff = btrfs_token_item_offset(&token, i); btrfs_set_token_item_offset(&token, i, ioff + size_diff); } /* shift the data */ if (from_end) { memmove_leaf_data(leaf, data_end + size_diff, data_end, old_data_start + new_size - data_end); } else { struct btrfs_disk_key disk_key; u64 offset; btrfs_item_key(leaf, &disk_key, slot); if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) { unsigned long ptr; struct btrfs_file_extent_item *fi; fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); fi = (struct btrfs_file_extent_item *)( (unsigned long)fi - size_diff); if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) { ptr = btrfs_item_ptr_offset(leaf, slot); memmove_extent_buffer(leaf, ptr, (unsigned long)fi, BTRFS_FILE_EXTENT_INLINE_DATA_START); } } memmove_leaf_data(leaf, data_end + size_diff, data_end, old_data_start - data_end); offset = btrfs_disk_key_offset(&disk_key); btrfs_set_disk_key_offset(&disk_key, offset + size_diff); btrfs_set_item_key(leaf, &disk_key, slot); if (slot == 0) fixup_low_keys(trans, path, &disk_key, 1); } btrfs_set_item_size(leaf, slot, new_size); btrfs_mark_buffer_dirty(trans, leaf); if (btrfs_leaf_free_space(leaf) < 0) { btrfs_print_leaf(leaf); BUG(); } } /* * make the item pointed to by the path bigger, data_size is the added size. */ void btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_path *path, u32 data_size) { int slot; struct extent_buffer *leaf; u32 nritems; unsigned int data_end; unsigned int old_data; unsigned int old_size; int i; struct btrfs_map_token token; leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); data_end = leaf_data_end(leaf); if (btrfs_leaf_free_space(leaf) < data_size) { btrfs_print_leaf(leaf); BUG(); } slot = path->slots[0]; old_data = btrfs_item_data_end(leaf, slot); BUG_ON(slot < 0); if (slot >= nritems) { btrfs_print_leaf(leaf); btrfs_crit(leaf->fs_info, "slot %d too large, nritems %d", slot, nritems); BUG(); } /* * item0..itemN ... dataN.offset..dataN.size .. data0.size */ /* first correct the data pointers */ btrfs_init_map_token(&token, leaf); for (i = slot; i < nritems; i++) { u32 ioff; ioff = btrfs_token_item_offset(&token, i); btrfs_set_token_item_offset(&token, i, ioff - data_size); } /* shift the data */ memmove_leaf_data(leaf, data_end - data_size, data_end, old_data - data_end); data_end = old_data; old_size = btrfs_item_size(leaf, slot); btrfs_set_item_size(leaf, slot, old_size + data_size); btrfs_mark_buffer_dirty(trans, leaf); if (btrfs_leaf_free_space(leaf) < 0) { btrfs_print_leaf(leaf); BUG(); } } /* * Make space in the node before inserting one or more items. * * @trans: transaction handle * @root: root we are inserting items to * @path: points to the leaf/slot where we are going to insert new items * @batch: information about the batch of items to insert * * Main purpose is to save stack depth by doing the bulk of the work in a * function that doesn't call btrfs_search_slot */ static void setup_items_for_insert(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, const struct btrfs_item_batch *batch) { struct btrfs_fs_info *fs_info = root->fs_info; int i; u32 nritems; unsigned int data_end; struct btrfs_disk_key disk_key; struct extent_buffer *leaf; int slot; struct btrfs_map_token token; u32 total_size; /* * Before anything else, update keys in the parent and other ancestors * if needed, then release the write locks on them, so that other tasks * can use them while we modify the leaf. */ if (path->slots[0] == 0) { btrfs_cpu_key_to_disk(&disk_key, &batch->keys[0]); fixup_low_keys(trans, path, &disk_key, 1); } btrfs_unlock_up_safe(path, 1); leaf = path->nodes[0]; slot = path->slots[0]; nritems = btrfs_header_nritems(leaf); data_end = leaf_data_end(leaf); total_size = batch->total_data_size + (batch->nr * sizeof(struct btrfs_item)); if (btrfs_leaf_free_space(leaf) < total_size) { btrfs_print_leaf(leaf); btrfs_crit(fs_info, "not enough freespace need %u have %d", total_size, btrfs_leaf_free_space(leaf)); BUG(); } btrfs_init_map_token(&token, leaf); if (slot != nritems) { unsigned int old_data = btrfs_item_data_end(leaf, slot); if (old_data < data_end) { btrfs_print_leaf(leaf); btrfs_crit(fs_info, "item at slot %d with data offset %u beyond data end of leaf %u", slot, old_data, data_end); BUG(); } /* * item0..itemN ... dataN.offset..dataN.size .. data0.size */ /* first correct the data pointers */ for (i = slot; i < nritems; i++) { u32 ioff; ioff = btrfs_token_item_offset(&token, i); btrfs_set_token_item_offset(&token, i, ioff - batch->total_data_size); } /* shift the items */ memmove_leaf_items(leaf, slot + batch->nr, slot, nritems - slot); /* shift the data */ memmove_leaf_data(leaf, data_end - batch->total_data_size, data_end, old_data - data_end); data_end = old_data; } /* setup the item for the new data */ for (i = 0; i < batch->nr; i++) { btrfs_cpu_key_to_disk(&disk_key, &batch->keys[i]); btrfs_set_item_key(leaf, &disk_key, slot + i); data_end -= batch->data_sizes[i]; btrfs_set_token_item_offset(&token, slot + i, data_end); btrfs_set_token_item_size(&token, slot + i, batch->data_sizes[i]); } btrfs_set_header_nritems(leaf, nritems + batch->nr); btrfs_mark_buffer_dirty(trans, leaf); if (btrfs_leaf_free_space(leaf) < 0) { btrfs_print_leaf(leaf); BUG(); } } /* * Insert a new item into a leaf. * * @trans: Transaction handle. * @root: The root of the btree. * @path: A path pointing to the target leaf and slot. * @key: The key of the new item. * @data_size: The size of the data associated with the new key. */ void btrfs_setup_item_for_insert(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, const struct btrfs_key *key, u32 data_size) { struct btrfs_item_batch batch; batch.keys = key; batch.data_sizes = &data_size; batch.total_data_size = data_size; batch.nr = 1; setup_items_for_insert(trans, root, path, &batch); } /* * Given a key and some data, insert items into the tree. * This does all the path init required, making room in the tree if needed. */ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, const struct btrfs_item_batch *batch) { int ret = 0; int slot; u32 total_size; total_size = batch->total_data_size + (batch->nr * sizeof(struct btrfs_item)); ret = btrfs_search_slot(trans, root, &batch->keys[0], path, total_size, 1); if (ret == 0) return -EEXIST; if (ret < 0) return ret; slot = path->slots[0]; BUG_ON(slot < 0); setup_items_for_insert(trans, root, path, batch); return 0; } /* * Given a key and some data, insert an item into the tree. * This does all the path init required, making room in the tree if needed. */ int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, const struct btrfs_key *cpu_key, void *data, u32 data_size) { int ret = 0; struct btrfs_path *path; struct extent_buffer *leaf; unsigned long ptr; path = btrfs_alloc_path(); if (!path) return -ENOMEM; ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size); if (!ret) { leaf = path->nodes[0]; ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); write_extent_buffer(leaf, data, ptr, data_size); btrfs_mark_buffer_dirty(trans, leaf); } btrfs_free_path(path); return ret; } /* * This function duplicates an item, giving 'new_key' to the new item. * It guarantees both items live in the same tree leaf and the new item is * contiguous with the original item. * * This allows us to split a file extent in place, keeping a lock on the leaf * the entire time. */ int btrfs_duplicate_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, const struct btrfs_key *new_key) { struct extent_buffer *leaf; int ret; u32 item_size; leaf = path->nodes[0]; item_size = btrfs_item_size(leaf, path->slots[0]); ret = setup_leaf_for_split(trans, root, path, item_size + sizeof(struct btrfs_item)); if (ret) return ret; path->slots[0]++; btrfs_setup_item_for_insert(trans, root, path, new_key, item_size); leaf = path->nodes[0]; memcpy_extent_buffer(leaf, btrfs_item_ptr_offset(leaf, path->slots[0]), btrfs_item_ptr_offset(leaf, path->slots[0] - 1), item_size); return 0; } /* * delete the pointer from a given node. * * the tree should have been previously balanced so the deletion does not * empty a node. * * This is exported for use inside btrfs-progs, don't un-export it. */ int btrfs_del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int level, int slot) { struct extent_buffer *parent = path->nodes[level]; u32 nritems; int ret; nritems = btrfs_header_nritems(parent); if (slot != nritems - 1) { if (level) { ret = btrfs_tree_mod_log_insert_move(parent, slot, slot + 1, nritems - slot - 1); if (ret < 0) { btrfs_abort_transaction(trans, ret); return ret; } } memmove_extent_buffer(parent, btrfs_node_key_ptr_offset(parent, slot), btrfs_node_key_ptr_offset(parent, slot + 1), sizeof(struct btrfs_key_ptr) * (nritems - slot - 1)); } else if (level) { ret = btrfs_tree_mod_log_insert_key(parent, slot, BTRFS_MOD_LOG_KEY_REMOVE); if (ret < 0) { btrfs_abort_transaction(trans, ret); return ret; } } nritems--; btrfs_set_header_nritems(parent, nritems); if (nritems == 0 && parent == root->node) { BUG_ON(btrfs_header_level(root->node) != 1); /* just turn the root into a leaf and break */ btrfs_set_header_level(root->node, 0); } else if (slot == 0) { struct btrfs_disk_key disk_key; btrfs_node_key(parent, &disk_key, 0); fixup_low_keys(trans, path, &disk_key, level + 1); } btrfs_mark_buffer_dirty(trans, parent); return 0; } /* * a helper function to delete the leaf pointed to by path->slots[1] and * path->nodes[1]. * * This deletes the pointer in path->nodes[1] and frees the leaf * block extent. zero is returned if it all worked out, < 0 otherwise. * * The path must have already been setup for deleting the leaf, including * all the proper balancing. path->nodes[1] must be locked. */ static noinline int btrfs_del_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct extent_buffer *leaf) { int ret; WARN_ON(btrfs_header_generation(leaf) != trans->transid); ret = btrfs_del_ptr(trans, root, path, 1, path->slots[1]); if (ret < 0) return ret; /* * btrfs_free_extent is expensive, we want to make sure we * aren't holding any locks when we call it */ btrfs_unlock_up_safe(path, 0); root_sub_used_bytes(root); atomic_inc(&leaf->refs); btrfs_free_tree_block(trans, btrfs_root_id(root), leaf, 0, 1); free_extent_buffer_stale(leaf); return 0; } /* * delete the item at the leaf level in path. If that empties * the leaf, remove it from the tree */ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, int slot, int nr) { struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *leaf; int ret = 0; int wret; u32 nritems; leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); if (slot + nr != nritems) { const u32 last_off = btrfs_item_offset(leaf, slot + nr - 1); const int data_end = leaf_data_end(leaf); struct btrfs_map_token token; u32 dsize = 0; int i; for (i = 0; i < nr; i++) dsize += btrfs_item_size(leaf, slot + i); memmove_leaf_data(leaf, data_end + dsize, data_end, last_off - data_end); btrfs_init_map_token(&token, leaf); for (i = slot + nr; i < nritems; i++) { u32 ioff; ioff = btrfs_token_item_offset(&token, i); btrfs_set_token_item_offset(&token, i, ioff + dsize); } memmove_leaf_items(leaf, slot, slot + nr, nritems - slot - nr); } btrfs_set_header_nritems(leaf, nritems - nr); nritems -= nr; /* delete the leaf if we've emptied it */ if (nritems == 0) { if (leaf == root->node) { btrfs_set_header_level(leaf, 0); } else { btrfs_clear_buffer_dirty(trans, leaf); ret = btrfs_del_leaf(trans, root, path, leaf); if (ret < 0) return ret; } } else { int used = leaf_space_used(leaf, 0, nritems); if (slot == 0) { struct btrfs_disk_key disk_key; btrfs_item_key(leaf, &disk_key, 0); fixup_low_keys(trans, path, &disk_key, 1); } /* * Try to delete the leaf if it is mostly empty. We do this by * trying to move all its items into its left and right neighbours. * If we can't move all the items, then we don't delete it - it's * not ideal, but future insertions might fill the leaf with more * items, or items from other leaves might be moved later into our * leaf due to deletions on those leaves. */ if (used < BTRFS_LEAF_DATA_SIZE(fs_info) / 3) { u32 min_push_space; /* push_leaf_left fixes the path. * make sure the path still points to our leaf * for possible call to btrfs_del_ptr below */ slot = path->slots[1]; atomic_inc(&leaf->refs); /* * We want to be able to at least push one item to the * left neighbour leaf, and that's the first item. */ min_push_space = sizeof(struct btrfs_item) + btrfs_item_size(leaf, 0); wret = push_leaf_left(trans, root, path, 0, min_push_space, 1, (u32)-1); if (wret < 0 && wret != -ENOSPC) ret = wret; if (path->nodes[0] == leaf && btrfs_header_nritems(leaf)) { /* * If we were not able to push all items from our * leaf to its left neighbour, then attempt to * either push all the remaining items to the * right neighbour or none. There's no advantage * in pushing only some items, instead of all, as * it's pointless to end up with a leaf having * too few items while the neighbours can be full * or nearly full. */ nritems = btrfs_header_nritems(leaf); min_push_space = leaf_space_used(leaf, 0, nritems); wret = push_leaf_right(trans, root, path, 0, min_push_space, 1, 0); if (wret < 0 && wret != -ENOSPC) ret = wret; } if (btrfs_header_nritems(leaf) == 0) { path->slots[1] = slot; ret = btrfs_del_leaf(trans, root, path, leaf); if (ret < 0) return ret; free_extent_buffer(leaf); ret = 0; } else { /* if we're still in the path, make sure * we're dirty. Otherwise, one of the * push_leaf functions must have already * dirtied this buffer */ if (path->nodes[0] == leaf) btrfs_mark_buffer_dirty(trans, leaf); free_extent_buffer(leaf); } } else { btrfs_mark_buffer_dirty(trans, leaf); } } return ret; } /* * A helper function to walk down the tree starting at min_key, and looking * for nodes or leaves that are have a minimum transaction id. * This is used by the btree defrag code, and tree logging * * This does not cow, but it does stuff the starting key it finds back * into min_key, so you can call btrfs_search_slot with cow=1 on the * key and get a writable path. * * This honors path->lowest_level to prevent descent past a given level * of the tree. * * min_trans indicates the oldest transaction that you are interested * in walking through. Any nodes or leaves older than min_trans are * skipped over (without reading them). * * returns zero if something useful was found, < 0 on error and 1 if there * was nothing in the tree that matched the search criteria. */ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, struct btrfs_path *path, u64 min_trans) { struct extent_buffer *cur; struct btrfs_key found_key; int slot; int sret; u32 nritems; int level; int ret = 1; int keep_locks = path->keep_locks; ASSERT(!path->nowait); path->keep_locks = 1; again: cur = btrfs_read_lock_root_node(root); level = btrfs_header_level(cur); WARN_ON(path->nodes[level]); path->nodes[level] = cur; path->locks[level] = BTRFS_READ_LOCK; if (btrfs_header_generation(cur) < min_trans) { ret = 1; goto out; } while (1) { nritems = btrfs_header_nritems(cur); level = btrfs_header_level(cur); sret = btrfs_bin_search(cur, 0, min_key, &slot); if (sret < 0) { ret = sret; goto out; } /* at the lowest level, we're done, setup the path and exit */ if (level == path->lowest_level) { if (slot >= nritems) goto find_next_key; ret = 0; path->slots[level] = slot; btrfs_item_key_to_cpu(cur, &found_key, slot); goto out; } if (sret && slot > 0) slot--; /* * check this node pointer against the min_trans parameters. * If it is too old, skip to the next one. */ while (slot < nritems) { u64 gen; gen = btrfs_node_ptr_generation(cur, slot); if (gen < min_trans) { slot++; continue; } break; } find_next_key: /* * we didn't find a candidate key in this node, walk forward * and find another one */ if (slot >= nritems) { path->slots[level] = slot; sret = btrfs_find_next_key(root, path, min_key, level, min_trans); if (sret == 0) { btrfs_release_path(path); goto again; } else { goto out; } } /* save our key for returning back */ btrfs_node_key_to_cpu(cur, &found_key, slot); path->slots[level] = slot; if (level == path->lowest_level) { ret = 0; goto out; } cur = btrfs_read_node_slot(cur, slot); if (IS_ERR(cur)) { ret = PTR_ERR(cur); goto out; } btrfs_tree_read_lock(cur); path->locks[level - 1] = BTRFS_READ_LOCK; path->nodes[level - 1] = cur; unlock_up(path, level, 1, 0, NULL); } out: path->keep_locks = keep_locks; if (ret == 0) { btrfs_unlock_up_safe(path, path->lowest_level + 1); memcpy(min_key, &found_key, sizeof(found_key)); } return ret; } /* * this is similar to btrfs_next_leaf, but does not try to preserve * and fixup the path. It looks for and returns the next key in the * tree based on the current path and the min_trans parameters. * * 0 is returned if another key is found, < 0 if there are any errors * and 1 is returned if there are no higher keys in the tree * * path->keep_locks should be set to 1 on the search made before * calling this function. */ int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path, struct btrfs_key *key, int level, u64 min_trans) { int slot; struct extent_buffer *c; WARN_ON(!path->keep_locks && !path->skip_locking); while (level < BTRFS_MAX_LEVEL) { if (!path->nodes[level]) return 1; slot = path->slots[level] + 1; c = path->nodes[level]; next: if (slot >= btrfs_header_nritems(c)) { int ret; int orig_lowest; struct btrfs_key cur_key; if (level + 1 >= BTRFS_MAX_LEVEL || !path->nodes[level + 1]) return 1; if (path->locks[level + 1] || path->skip_locking) { level++; continue; } slot = btrfs_header_nritems(c) - 1; if (level == 0) btrfs_item_key_to_cpu(c, &cur_key, slot); else btrfs_node_key_to_cpu(c, &cur_key, slot); orig_lowest = path->lowest_level; btrfs_release_path(path); path->lowest_level = level; ret = btrfs_search_slot(NULL, root, &cur_key, path, 0, 0); path->lowest_level = orig_lowest; if (ret < 0) return ret; c = path->nodes[level]; slot = path->slots[level]; if (ret == 0) slot++; goto next; } if (level == 0) btrfs_item_key_to_cpu(c, key, slot); else { u64 gen = btrfs_node_ptr_generation(c, slot); if (gen < min_trans) { slot++; goto next; } btrfs_node_key_to_cpu(c, key, slot); } return 0; } return 1; } int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, u64 time_seq) { int slot; int level; struct extent_buffer *c; struct extent_buffer *next; struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_key key; bool need_commit_sem = false; u32 nritems; int ret; int i; /* * The nowait semantics are used only for write paths, where we don't * use the tree mod log and sequence numbers. */ if (time_seq) ASSERT(!path->nowait); nritems = btrfs_header_nritems(path->nodes[0]); if (nritems == 0) return 1; btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1); again: level = 1; next = NULL; btrfs_release_path(path); path->keep_locks = 1; if (time_seq) { ret = btrfs_search_old_slot(root, &key, path, time_seq); } else { if (path->need_commit_sem) { path->need_commit_sem = 0; need_commit_sem = true; if (path->nowait) { if (!down_read_trylock(&fs_info->commit_root_sem)) { ret = -EAGAIN; goto done; } } else { down_read(&fs_info->commit_root_sem); } } ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); } path->keep_locks = 0; if (ret < 0) goto done; nritems = btrfs_header_nritems(path->nodes[0]); /* * by releasing the path above we dropped all our locks. A balance * could have added more items next to the key that used to be * at the very end of the block. So, check again here and * advance the path if there are now more items available. */ if (nritems > 0 && path->slots[0] < nritems - 1) { if (ret == 0) path->slots[0]++; ret = 0; goto done; } /* * So the above check misses one case: * - after releasing the path above, someone has removed the item that * used to be at the very end of the block, and balance between leafs * gets another one with bigger key.offset to replace it. * * This one should be returned as well, or we can get leaf corruption * later(esp. in __btrfs_drop_extents()). * * And a bit more explanation about this check, * with ret > 0, the key isn't found, the path points to the slot * where it should be inserted, so the path->slots[0] item must be the * bigger one. */ if (nritems > 0 && ret > 0 && path->slots[0] == nritems - 1) { ret = 0; goto done; } while (level < BTRFS_MAX_LEVEL) { if (!path->nodes[level]) { ret = 1; goto done; } slot = path->slots[level] + 1; c = path->nodes[level]; if (slot >= btrfs_header_nritems(c)) { level++; if (level == BTRFS_MAX_LEVEL) { ret = 1; goto done; } continue; } /* * Our current level is where we're going to start from, and to * make sure lockdep doesn't complain we need to drop our locks * and nodes from 0 to our current level. */ for (i = 0; i < level; i++) { if (path->locks[level]) { btrfs_tree_read_unlock(path->nodes[i]); path->locks[i] = 0; } free_extent_buffer(path->nodes[i]); path->nodes[i] = NULL; } next = c; ret = read_block_for_search(root, path, &next, level, slot, &key); if (ret == -EAGAIN && !path->nowait) goto again; if (ret < 0) { btrfs_release_path(path); goto done; } if (!path->skip_locking) { ret = btrfs_try_tree_read_lock(next); if (!ret && path->nowait) { ret = -EAGAIN; goto done; } if (!ret && time_seq) { /* * If we don't get the lock, we may be racing * with push_leaf_left, holding that lock while * itself waiting for the leaf we've currently * locked. To solve this situation, we give up * on our lock and cycle. */ free_extent_buffer(next); btrfs_release_path(path); cond_resched(); goto again; } if (!ret) btrfs_tree_read_lock(next); } break; } path->slots[level] = slot; while (1) { level--; path->nodes[level] = next; path->slots[level] = 0; if (!path->skip_locking) path->locks[level] = BTRFS_READ_LOCK; if (!level) break; ret = read_block_for_search(root, path, &next, level, 0, &key); if (ret == -EAGAIN && !path->nowait) goto again; if (ret < 0) { btrfs_release_path(path); goto done; } if (!path->skip_locking) { if (path->nowait) { if (!btrfs_try_tree_read_lock(next)) { ret = -EAGAIN; goto done; } } else { btrfs_tree_read_lock(next); } } } ret = 0; done: unlock_up(path, 0, 1, 0, NULL); if (need_commit_sem) { int ret2; path->need_commit_sem = 1; ret2 = finish_need_commit_sem_search(path); up_read(&fs_info->commit_root_sem); if (ret2) ret = ret2; } return ret; } int btrfs_next_old_item(struct btrfs_root *root, struct btrfs_path *path, u64 time_seq) { path->slots[0]++; if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) return btrfs_next_old_leaf(root, path, time_seq); return 0; } /* * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps * searching until it gets past min_objectid or finds an item of 'type' * * returns 0 if something is found, 1 if nothing was found and < 0 on error */ int btrfs_previous_item(struct btrfs_root *root, struct btrfs_path *path, u64 min_objectid, int type) { struct btrfs_key found_key; struct extent_buffer *leaf; u32 nritems; int ret; while (1) { if (path->slots[0] == 0) { ret = btrfs_prev_leaf(root, path); if (ret != 0) return ret; } else { path->slots[0]--; } leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); if (nritems == 0) return 1; if (path->slots[0] == nritems) path->slots[0]--; btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); if (found_key.objectid < min_objectid) break; if (found_key.type == type) return 0; if (found_key.objectid == min_objectid && found_key.type < type) break; } return 1; } /* * search in extent tree to find a previous Metadata/Data extent item with * min objecitd. * * returns 0 if something is found, 1 if nothing was found and < 0 on error */ int btrfs_previous_extent_item(struct btrfs_root *root, struct btrfs_path *path, u64 min_objectid) { struct btrfs_key found_key; struct extent_buffer *leaf; u32 nritems; int ret; while (1) { if (path->slots[0] == 0) { ret = btrfs_prev_leaf(root, path); if (ret != 0) return ret; } else { path->slots[0]--; } leaf = path->nodes[0]; nritems = btrfs_header_nritems(leaf); if (nritems == 0) return 1; if (path->slots[0] == nritems) path->slots[0]--; btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); if (found_key.objectid < min_objectid) break; if (found_key.type == BTRFS_EXTENT_ITEM_KEY || found_key.type == BTRFS_METADATA_ITEM_KEY) return 0; if (found_key.objectid == min_objectid && found_key.type < BTRFS_EXTENT_ITEM_KEY) break; } return 1; } int __init btrfs_ctree_init(void) { btrfs_path_cachep = kmem_cache_create("btrfs_path", sizeof(struct btrfs_path), 0, SLAB_MEM_SPREAD, NULL); if (!btrfs_path_cachep) return -ENOMEM; return 0; } void __cold btrfs_ctree_exit(void) { kmem_cache_destroy(btrfs_path_cachep); }
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