| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Chris Mason | 10882 | 44.36% | 126 | 35.59% |
| Zheng Yan | 4311 | 17.57% | 17 | 4.80% |
| Jan Schmidt | 3674 | 14.98% | 23 | 6.50% |
| Filipe David Borba Manana | 2204 | 8.98% | 21 | 5.93% |
| David Sterba | 609 | 2.48% | 48 | 13.56% |
| Liu Bo | 499 | 2.03% | 19 | 5.37% |
| Josef Bacik | 458 | 1.87% | 22 | 6.21% |
| Qu Wenruo | 401 | 1.63% | 6 | 1.69% |
| Jeff Mahoney | 301 | 1.23% | 9 | 2.54% |
| Arne Jansen | 237 | 0.97% | 3 | 0.85% |
| Shilong Wang | 190 | 0.77% | 1 | 0.28% |
| Kelley Nielsen | 176 | 0.72% | 2 | 0.56% |
| Johannes Thumshirn | 114 | 0.46% | 3 | 0.85% |
| Nikolay Borisov | 96 | 0.39% | 8 | 2.26% |
| Mark Fasheh | 85 | 0.35% | 4 | 1.13% |
| Miao Xie | 54 | 0.22% | 1 | 0.28% |
| Tsutomu Itoh | 42 | 0.17% | 4 | 1.13% |
| Yan Zheng | 21 | 0.09% | 3 | 0.85% |
| Frank Holton | 20 | 0.08% | 1 | 0.28% |
| Omar Sandoval | 19 | 0.08% | 1 | 0.28% |
| Chandan Rajendra | 16 | 0.07% | 2 | 0.56% |
| Daniel Dressler | 16 | 0.07% | 2 | 0.56% |
| Julia Lawall | 15 | 0.06% | 2 | 0.56% |
| Zhao Lei | 9 | 0.04% | 1 | 0.28% |
| Anand Jain | 9 | 0.04% | 2 | 0.56% |
| Josef Whiter | 9 | 0.04% | 1 | 0.28% |
| Nicholas D Steeves | 6 | 0.02% | 1 | 0.28% |
| Jesper Juhl | 6 | 0.02% | 1 | 0.28% |
| Dulshani Gunawardhana | 5 | 0.02% | 1 | 0.28% |
| Goldwyn Rodrigues | 5 | 0.02% | 1 | 0.28% |
| Jens Axboe | 4 | 0.02% | 1 | 0.28% |
| Arnd Bergmann | 4 | 0.02% | 1 | 0.28% |
| Geliang Tang | 4 | 0.02% | 1 | 0.28% |
| Li Zefan | 3 | 0.01% | 1 | 0.28% |
| Tejun Heo | 3 | 0.01% | 1 | 0.28% |
| Eric Sandeen | 3 | 0.01% | 2 | 0.56% |
| Stefan Behrens | 3 | 0.01% | 2 | 0.56% |
| Diego Calleja García | 3 | 0.01% | 1 | 0.28% |
| Byongho Lee | 3 | 0.01% | 1 | 0.28% |
| Stoyan Gaydarov | 3 | 0.01% | 1 | 0.28% |
| Andrea Gelmini | 2 | 0.01% | 1 | 0.28% |
| Alexandru Moise | 2 | 0.01% | 1 | 0.28% |
| Misono, Tomohiro | 2 | 0.01% | 1 | 0.28% |
| Masahiro Yamada | 1 | 0.00% | 1 | 0.28% |
| Aneesh Kumar K.V | 1 | 0.00% | 1 | 0.28% |
| Christoph Hellwig | 1 | 0.00% | 1 | 0.28% |
| Total | 24531 | 354 |
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// 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 "ctree.h" #include "disk-io.h" #include "transaction.h" #include "print-tree.h" #include "locking.h" #include "volumes.h" #include "qgroup.h" 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 void del_ptr(struct btrfs_root *root, struct btrfs_path *path, int level, int slot); static const struct btrfs_csums { u16 size; const char *name; const char *driver; } 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" }, }; 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_csums[t].size; } 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 ?: btrfs_csums[csum_type].name; } size_t __const btrfs_get_num_csums(void) { return ARRAY_SIZE(btrfs_csums); } struct btrfs_path *btrfs_alloc_path(void) { 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; } } /* * 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; } /* loop around taking references on and locking the root node of the * tree until you end up with a lock on the root. A locked buffer * is returned, with a reference held. */ struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root) { struct extent_buffer *eb; while (1) { eb = btrfs_root_node(root); btrfs_tree_lock(eb); if (eb == root->node) break; btrfs_tree_unlock(eb); free_extent_buffer(eb); } return eb; } /* loop around taking references on and locking the root node of the * tree until you end up with a lock on the root. A locked buffer * is returned, with a reference held. */ struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root) { struct extent_buffer *eb; while (1) { eb = btrfs_root_node(root); btrfs_tree_read_lock(eb); if (eb == root->node) break; btrfs_tree_read_unlock(eb); free_extent_buffer(eb); } return eb; } /* cowonly root (everything not a reference counted cow subvolume), just get * put onto a simple dirty list. transaction.c walks this 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; WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) && trans->transid != fs_info->running_transaction->transid); WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &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); cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid, &disk_key, level, buf->start, 0); 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) return ret; btrfs_mark_buffer_dirty(cow); *cow_ret = cow; return 0; } enum mod_log_op { MOD_LOG_KEY_REPLACE, MOD_LOG_KEY_ADD, MOD_LOG_KEY_REMOVE, MOD_LOG_KEY_REMOVE_WHILE_FREEING, MOD_LOG_KEY_REMOVE_WHILE_MOVING, MOD_LOG_MOVE_KEYS, MOD_LOG_ROOT_REPLACE, }; struct tree_mod_root { u64 logical; u8 level; }; struct tree_mod_elem { struct rb_node node; u64 logical; u64 seq; enum mod_log_op op; /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */ int slot; /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */ u64 generation; /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */ struct btrfs_disk_key key; u64 blockptr; /* this is used for op == MOD_LOG_MOVE_KEYS */ struct { int dst_slot; int nr_items; } move; /* this is used for op == MOD_LOG_ROOT_REPLACE */ struct tree_mod_root old_root; }; /* * Pull a new tree mod seq number for our operation. */ static inline u64 btrfs_inc_tree_mod_seq(struct btrfs_fs_info *fs_info) { return atomic64_inc_return(&fs_info->tree_mod_seq); } /* * This adds a new blocker to the tree mod log's blocker list if the @elem * passed does not already have a sequence number set. So when a caller expects * to record tree modifications, it should ensure to set elem->seq to zero * before calling btrfs_get_tree_mod_seq. * Returns a fresh, unused tree log modification sequence number, even if no new * blocker was added. */ u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info, struct seq_list *elem) { write_lock(&fs_info->tree_mod_log_lock); if (!elem->seq) { elem->seq = btrfs_inc_tree_mod_seq(fs_info); list_add_tail(&elem->list, &fs_info->tree_mod_seq_list); } write_unlock(&fs_info->tree_mod_log_lock); return elem->seq; } void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info, struct seq_list *elem) { struct rb_root *tm_root; struct rb_node *node; struct rb_node *next; struct seq_list *cur_elem; struct tree_mod_elem *tm; u64 min_seq = (u64)-1; u64 seq_putting = elem->seq; if (!seq_putting) return; write_lock(&fs_info->tree_mod_log_lock); list_del(&elem->list); elem->seq = 0; list_for_each_entry(cur_elem, &fs_info->tree_mod_seq_list, list) { if (cur_elem->seq < min_seq) { if (seq_putting > cur_elem->seq) { /* * blocker with lower sequence number exists, we * cannot remove anything from the log */ write_unlock(&fs_info->tree_mod_log_lock); return; } min_seq = cur_elem->seq; } } /* * anything that's lower than the lowest existing (read: blocked) * sequence number can be removed from the tree. */ tm_root = &fs_info->tree_mod_log; for (node = rb_first(tm_root); node; node = next) { next = rb_next(node); tm = rb_entry(node, struct tree_mod_elem, node); if (tm->seq >= min_seq) continue; rb_erase(node, tm_root); kfree(tm); } write_unlock(&fs_info->tree_mod_log_lock); } /* * key order of the log: * node/leaf start address -> sequence * * The 'start address' is the logical address of the *new* root node * for root replace operations, or the logical address of the affected * block for all other operations. */ static noinline int __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm) { struct rb_root *tm_root; struct rb_node **new; struct rb_node *parent = NULL; struct tree_mod_elem *cur; lockdep_assert_held_write(&fs_info->tree_mod_log_lock); tm->seq = btrfs_inc_tree_mod_seq(fs_info); tm_root = &fs_info->tree_mod_log; new = &tm_root->rb_node; while (*new) { cur = rb_entry(*new, struct tree_mod_elem, node); parent = *new; if (cur->logical < tm->logical) new = &((*new)->rb_left); else if (cur->logical > tm->logical) new = &((*new)->rb_right); else if (cur->seq < tm->seq) new = &((*new)->rb_left); else if (cur->seq > tm->seq) new = &((*new)->rb_right); else return -EEXIST; } rb_link_node(&tm->node, parent, new); rb_insert_color(&tm->node, tm_root); return 0; } /* * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it * returns zero with the tree_mod_log_lock acquired. The caller must hold * this until all tree mod log insertions are recorded in the rb tree and then * write unlock fs_info::tree_mod_log_lock. */ static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info, struct extent_buffer *eb) { smp_mb(); if (list_empty(&(fs_info)->tree_mod_seq_list)) return 1; if (eb && btrfs_header_level(eb) == 0) return 1; write_lock(&fs_info->tree_mod_log_lock); if (list_empty(&(fs_info)->tree_mod_seq_list)) { write_unlock(&fs_info->tree_mod_log_lock); return 1; } return 0; } /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */ static inline int tree_mod_need_log(const struct btrfs_fs_info *fs_info, struct extent_buffer *eb) { smp_mb(); if (list_empty(&(fs_info)->tree_mod_seq_list)) return 0; if (eb && btrfs_header_level(eb) == 0) return 0; return 1; } static struct tree_mod_elem * alloc_tree_mod_elem(struct extent_buffer *eb, int slot, enum mod_log_op op, gfp_t flags) { struct tree_mod_elem *tm; tm = kzalloc(sizeof(*tm), flags); if (!tm) return NULL; tm->logical = eb->start; if (op != MOD_LOG_KEY_ADD) { btrfs_node_key(eb, &tm->key, slot); tm->blockptr = btrfs_node_blockptr(eb, slot); } tm->op = op; tm->slot = slot; tm->generation = btrfs_node_ptr_generation(eb, slot); RB_CLEAR_NODE(&tm->node); return tm; } static noinline int tree_mod_log_insert_key(struct extent_buffer *eb, int slot, enum mod_log_op op, gfp_t flags) { struct tree_mod_elem *tm; int ret; if (!tree_mod_need_log(eb->fs_info, eb)) return 0; tm = alloc_tree_mod_elem(eb, slot, op, flags); if (!tm) return -ENOMEM; if (tree_mod_dont_log(eb->fs_info, eb)) { kfree(tm); return 0; } ret = __tree_mod_log_insert(eb->fs_info, tm); write_unlock(&eb->fs_info->tree_mod_log_lock); if (ret) kfree(tm); return ret; } static noinline int tree_mod_log_insert_move(struct extent_buffer *eb, int dst_slot, int src_slot, int nr_items) { struct tree_mod_elem *tm = NULL; struct tree_mod_elem **tm_list = NULL; int ret = 0; int i; int locked = 0; if (!tree_mod_need_log(eb->fs_info, eb)) return 0; tm_list = kcalloc(nr_items, sizeof(struct tree_mod_elem *), GFP_NOFS); if (!tm_list) return -ENOMEM; tm = kzalloc(sizeof(*tm), GFP_NOFS); if (!tm) { ret = -ENOMEM; goto free_tms; } tm->logical = eb->start; tm->slot = src_slot; tm->move.dst_slot = dst_slot; tm->move.nr_items = nr_items; tm->op = MOD_LOG_MOVE_KEYS; for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) { tm_list[i] = alloc_tree_mod_elem(eb, i + dst_slot, MOD_LOG_KEY_REMOVE_WHILE_MOVING, GFP_NOFS); if (!tm_list[i]) { ret = -ENOMEM; goto free_tms; } } if (tree_mod_dont_log(eb->fs_info, eb)) goto free_tms; locked = 1; /* * When we override something during the move, we log these removals. * This can only happen when we move towards the beginning of the * buffer, i.e. dst_slot < src_slot. */ for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) { ret = __tree_mod_log_insert(eb->fs_info, tm_list[i]); if (ret) goto free_tms; } ret = __tree_mod_log_insert(eb->fs_info, tm); if (ret) goto free_tms; write_unlock(&eb->fs_info->tree_mod_log_lock); kfree(tm_list); return 0; free_tms: for (i = 0; i < nr_items; i++) { if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node)) rb_erase(&tm_list[i]->node, &eb->fs_info->tree_mod_log); kfree(tm_list[i]); } if (locked) write_unlock(&eb->fs_info->tree_mod_log_lock); kfree(tm_list); kfree(tm); return ret; } static inline int __tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct tree_mod_elem **tm_list, int nritems) { int i, j; int ret; for (i = nritems - 1; i >= 0; i--) { ret = __tree_mod_log_insert(fs_info, tm_list[i]); if (ret) { for (j = nritems - 1; j > i; j--) rb_erase(&tm_list[j]->node, &fs_info->tree_mod_log); return ret; } } return 0; } static noinline int tree_mod_log_insert_root(struct extent_buffer *old_root, struct extent_buffer *new_root, int log_removal) { struct btrfs_fs_info *fs_info = old_root->fs_info; struct tree_mod_elem *tm = NULL; struct tree_mod_elem **tm_list = NULL; int nritems = 0; int ret = 0; int i; if (!tree_mod_need_log(fs_info, NULL)) return 0; if (log_removal && btrfs_header_level(old_root) > 0) { nritems = btrfs_header_nritems(old_root); tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *), GFP_NOFS); if (!tm_list) { ret = -ENOMEM; goto free_tms; } for (i = 0; i < nritems; i++) { tm_list[i] = alloc_tree_mod_elem(old_root, i, MOD_LOG_KEY_REMOVE_WHILE_FREEING, GFP_NOFS); if (!tm_list[i]) { ret = -ENOMEM; goto free_tms; } } } tm = kzalloc(sizeof(*tm), GFP_NOFS); if (!tm) { ret = -ENOMEM; goto free_tms; } tm->logical = new_root->start; tm->old_root.logical = old_root->start; tm->old_root.level = btrfs_header_level(old_root); tm->generation = btrfs_header_generation(old_root); tm->op = MOD_LOG_ROOT_REPLACE; if (tree_mod_dont_log(fs_info, NULL)) goto free_tms; if (tm_list) ret = __tree_mod_log_free_eb(fs_info, tm_list, nritems); if (!ret) ret = __tree_mod_log_insert(fs_info, tm); write_unlock(&fs_info->tree_mod_log_lock); if (ret) goto free_tms; kfree(tm_list); return ret; free_tms: if (tm_list) { for (i = 0; i < nritems; i++) kfree(tm_list[i]); kfree(tm_list); } kfree(tm); return ret; } static struct tree_mod_elem * __tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq, int smallest) { struct rb_root *tm_root; struct rb_node *node; struct tree_mod_elem *cur = NULL; struct tree_mod_elem *found = NULL; read_lock(&fs_info->tree_mod_log_lock); tm_root = &fs_info->tree_mod_log; node = tm_root->rb_node; while (node) { cur = rb_entry(node, struct tree_mod_elem, node); if (cur->logical < start) { node = node->rb_left; } else if (cur->logical > start) { node = node->rb_right; } else if (cur->seq < min_seq) { node = node->rb_left; } else if (!smallest) { /* we want the node with the highest seq */ if (found) BUG_ON(found->seq > cur->seq); found = cur; node = node->rb_left; } else if (cur->seq > min_seq) { /* we want the node with the smallest seq */ if (found) BUG_ON(found->seq < cur->seq); found = cur; node = node->rb_right; } else { found = cur; break; } } read_unlock(&fs_info->tree_mod_log_lock); return found; } /* * this returns the element from the log with the smallest time sequence * value that's in the log (the oldest log item). any element with a time * sequence lower than min_seq will be ignored. */ static struct tree_mod_elem * tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq) { return __tree_mod_log_search(fs_info, start, min_seq, 1); } /* * this returns the element from the log with the largest time sequence * value that's in the log (the most recent log item). any element with * a time sequence lower than min_seq will be ignored. */ static struct tree_mod_elem * tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq) { return __tree_mod_log_search(fs_info, start, min_seq, 0); } static noinline int tree_mod_log_eb_copy(struct extent_buffer *dst, struct extent_buffer *src, unsigned long dst_offset, unsigned long src_offset, int nr_items) { struct btrfs_fs_info *fs_info = dst->fs_info; int ret = 0; struct tree_mod_elem **tm_list = NULL; struct tree_mod_elem **tm_list_add, **tm_list_rem; int i; int locked = 0; if (!tree_mod_need_log(fs_info, NULL)) return 0; if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0) return 0; tm_list = kcalloc(nr_items * 2, sizeof(struct tree_mod_elem *), GFP_NOFS); if (!tm_list) return -ENOMEM; tm_list_add = tm_list; tm_list_rem = tm_list + nr_items; for (i = 0; i < nr_items; i++) { tm_list_rem[i] = alloc_tree_mod_elem(src, i + src_offset, MOD_LOG_KEY_REMOVE, GFP_NOFS); if (!tm_list_rem[i]) { ret = -ENOMEM; goto free_tms; } tm_list_add[i] = alloc_tree_mod_elem(dst, i + dst_offset, MOD_LOG_KEY_ADD, GFP_NOFS); if (!tm_list_add[i]) { ret = -ENOMEM; goto free_tms; } } if (tree_mod_dont_log(fs_info, NULL)) goto free_tms; locked = 1; for (i = 0; i < nr_items; i++) { ret = __tree_mod_log_insert(fs_info, tm_list_rem[i]); if (ret) goto free_tms; ret = __tree_mod_log_insert(fs_info, tm_list_add[i]); if (ret) goto free_tms; } write_unlock(&fs_info->tree_mod_log_lock); kfree(tm_list); return 0; free_tms: for (i = 0; i < nr_items * 2; i++) { if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node)) rb_erase(&tm_list[i]->node, &fs_info->tree_mod_log); kfree(tm_list[i]); } if (locked) write_unlock(&fs_info->tree_mod_log_lock); kfree(tm_list); return ret; } static noinline int tree_mod_log_free_eb(struct extent_buffer *eb) { struct tree_mod_elem **tm_list = NULL; int nritems = 0; int i; int ret = 0; if (btrfs_header_level(eb) == 0) return 0; if (!tree_mod_need_log(eb->fs_info, NULL)) return 0; nritems = btrfs_header_nritems(eb); tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *), GFP_NOFS); if (!tm_list) return -ENOMEM; for (i = 0; i < nritems; i++) { tm_list[i] = alloc_tree_mod_elem(eb, i, MOD_LOG_KEY_REMOVE_WHILE_FREEING, GFP_NOFS); if (!tm_list[i]) { ret = -ENOMEM; goto free_tms; } } if (tree_mod_dont_log(eb->fs_info, eb)) goto free_tms; ret = __tree_mod_log_free_eb(eb->fs_info, tm_list, nritems); write_unlock(&eb->fs_info->tree_mod_log_lock); if (ret) goto free_tms; kfree(tm_list); return 0; free_tms: for (i = 0; i < nritems; i++) kfree(tm_list[i]); kfree(tm_list); return ret; } /* * check if the tree block can be shared by multiple trees */ int btrfs_block_can_be_shared(struct btrfs_root *root, struct extent_buffer *buf) { /* * Tree blocks not in reference counted 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_REF_COWS, &root->state) && buf != root->node && buf != root->commit_root && (btrfs_header_generation(buf) <= btrfs_root_last_snapshot(&root->root_item) || btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) 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(root, buf)) { ret = btrfs_lookup_extent_info(trans, fs_info, buf->start, btrfs_header_level(buf), 1, &refs, &flags); if (ret) return ret; if (refs == 0) { ret = -EROFS; btrfs_handle_fs_error(fs_info, ret, NULL); 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) { int level = btrfs_header_level(buf); ret = btrfs_set_disk_extent_flags(trans, buf->start, buf->len, new_flags, level, 0); 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_clean_tree_block(buf); *last_ref = 1; } return 0; } static struct extent_buffer *alloc_tree_block_no_bg_flush( struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 parent_start, const struct btrfs_disk_key *disk_key, int level, u64 hint, u64 empty_size) { struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *ret; /* * If we are COWing a node/leaf from the extent, chunk, device or free * space trees, make sure that we do not finish block group creation of * pending block groups. We do this to avoid a deadlock. * COWing can result in allocation of a new chunk, and flushing pending * block groups (btrfs_create_pending_block_groups()) can be triggered * when finishing allocation of a new chunk. Creation of a pending block * group modifies the extent, chunk, device and free space trees, * therefore we could deadlock with ourselves since we are holding a * lock on an extent buffer that btrfs_create_pending_block_groups() may * try to COW later. * For similar reasons, we also need to delay flushing pending block * groups when splitting a leaf or node, from one of those trees, since * we are holding a write lock on it and its parent or when inserting a * new root node for one of those trees. */ if (root == fs_info->extent_root || root == fs_info->chunk_root || root == fs_info->dev_root || root == fs_info->free_space_root) trans->can_flush_pending_bgs = false; ret = btrfs_alloc_tree_block(trans, root, parent_start, root->root_key.objectid, disk_key, level, hint, empty_size); trans->can_flush_pending_bgs = true; return ret; } /* * 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. */ static noinline 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, u64 search_start, u64 empty_size) { 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; if (*cow_ret == buf) unlock_orig = 1; btrfs_assert_tree_locked(buf); WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) && trans->transid != fs_info->running_transaction->transid); WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &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) && parent) parent_start = parent->start; cow = alloc_tree_block_no_bg_flush(trans, root, parent_start, &disk_key, level, search_start, empty_size); 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_abort_transaction(trans, ret); return ret; } if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) { ret = btrfs_reloc_cow_block(trans, root, buf, cow); if (ret) { 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; atomic_inc(&cow->refs); ret = tree_mod_log_insert_root(root->node, cow, 1); BUG_ON(ret < 0); rcu_assign_pointer(root->node, cow); btrfs_free_tree_block(trans, 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)); tree_mod_log_insert_key(parent, parent_slot, MOD_LOG_KEY_REPLACE, GFP_NOFS); btrfs_set_node_blockptr(parent, parent_slot, cow->start); btrfs_set_node_ptr_generation(parent, parent_slot, trans->transid); btrfs_mark_buffer_dirty(parent); if (last_ref) { ret = tree_mod_log_free_eb(buf); if (ret) { btrfs_abort_transaction(trans, ret); return ret; } } btrfs_free_tree_block(trans, root, buf, parent_start, last_ref); } if (unlock_orig) btrfs_tree_unlock(buf); free_extent_buffer_stale(buf); btrfs_mark_buffer_dirty(cow); *cow_ret = cow; return 0; } /* * returns the logical address of the oldest predecessor of the given root. * entries older than time_seq are ignored. */ static struct tree_mod_elem *__tree_mod_log_oldest_root( struct extent_buffer *eb_root, u64 time_seq) { struct tree_mod_elem *tm; struct tree_mod_elem *found = NULL; u64 root_logical = eb_root->start; int looped = 0; if (!time_seq) return NULL; /* * the very last operation that's logged for a root is the * replacement operation (if it is replaced at all). this has * the logical address of the *new* root, making it the very * first operation that's logged for this root. */ while (1) { tm = tree_mod_log_search_oldest(eb_root->fs_info, root_logical, time_seq); if (!looped && !tm) return NULL; /* * if there are no tree operation for the oldest root, we simply * return it. this should only happen if that (old) root is at * level 0. */ if (!tm) break; /* * if there's an operation that's not a root replacement, we * found the oldest version of our root. normally, we'll find a * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here. */ if (tm->op != MOD_LOG_ROOT_REPLACE) break; found = tm; root_logical = tm->old_root.logical; looped = 1; } /* if there's no old root to return, return what we found instead */ if (!found) found = tm; return found; } /* * tm is a pointer to the first operation to rewind within eb. then, all * previous operations will be rewound (until we reach something older than * time_seq). */ static void __tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb, u64 time_seq, struct tree_mod_elem *first_tm) { u32 n; struct rb_node *next; struct tree_mod_elem *tm = first_tm; unsigned long o_dst; unsigned long o_src; unsigned long p_size = sizeof(struct btrfs_key_ptr); n = btrfs_header_nritems(eb); read_lock(&fs_info->tree_mod_log_lock); while (tm && tm->seq >= time_seq) { /* * all the operations are recorded with the operator used for * the modification. as we're going backwards, we do the * opposite of each operation here. */ switch (tm->op) { case MOD_LOG_KEY_REMOVE_WHILE_FREEING: BUG_ON(tm->slot < n); /* Fallthrough */ case MOD_LOG_KEY_REMOVE_WHILE_MOVING: case MOD_LOG_KEY_REMOVE: btrfs_set_node_key(eb, &tm->key, tm->slot); btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr); btrfs_set_node_ptr_generation(eb, tm->slot, tm->generation); n++; break; case MOD_LOG_KEY_REPLACE: BUG_ON(tm->slot >= n); btrfs_set_node_key(eb, &tm->key, tm->slot); btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr); btrfs_set_node_ptr_generation(eb, tm->slot, tm->generation); break; case MOD_LOG_KEY_ADD: /* if a move operation is needed it's in the log */ n--; break; case MOD_LOG_MOVE_KEYS: o_dst = btrfs_node_key_ptr_offset(tm->slot); o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot); memmove_extent_buffer(eb, o_dst, o_src, tm->move.nr_items * p_size); break; case MOD_LOG_ROOT_REPLACE: /* * this operation is special. for roots, this must be * handled explicitly before rewinding. * for non-roots, this operation may exist if the node * was a root: root A -> child B; then A gets empty and * B is promoted to the new root. in the mod log, we'll * have a root-replace operation for B, a tree block * that is no root. we simply ignore that operation. */ break; } next = rb_next(&tm->node); if (!next) break; tm = rb_entry(next, struct tree_mod_elem, node); if (tm->logical != first_tm->logical) break; } read_unlock(&fs_info->tree_mod_log_lock); btrfs_set_header_nritems(eb, n); } /* * Called with eb read locked. If the buffer cannot be rewound, the same buffer * is returned. If rewind operations happen, a fresh buffer is returned. The * returned buffer is always read-locked. If the returned buffer is not the * input buffer, the lock on the input buffer is released and the input buffer * is freed (its refcount is decremented). */ static struct extent_buffer * tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct btrfs_path *path, struct extent_buffer *eb, u64 time_seq) { struct extent_buffer *eb_rewin; struct tree_mod_elem *tm; if (!time_seq) return eb; if (btrfs_header_level(eb) == 0) return eb; tm = tree_mod_log_search(fs_info, eb->start, time_seq); if (!tm) return eb; btrfs_set_path_blocking(path); btrfs_set_lock_blocking_read(eb); if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) { BUG_ON(tm->slot != 0); eb_rewin = alloc_dummy_extent_buffer(fs_info, eb->start); if (!eb_rewin) { btrfs_tree_read_unlock_blocking(eb); free_extent_buffer(eb); return NULL; } btrfs_set_header_bytenr(eb_rewin, eb->start); btrfs_set_header_backref_rev(eb_rewin, btrfs_header_backref_rev(eb)); btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb)); btrfs_set_header_level(eb_rewin, btrfs_header_level(eb)); } else { eb_rewin = btrfs_clone_extent_buffer(eb); if (!eb_rewin) { btrfs_tree_read_unlock_blocking(eb); free_extent_buffer(eb); return NULL; } } btrfs_tree_read_unlock_blocking(eb); free_extent_buffer(eb); btrfs_tree_read_lock(eb_rewin); __tree_mod_log_rewind(fs_info, eb_rewin, time_seq, tm); WARN_ON(btrfs_header_nritems(eb_rewin) > BTRFS_NODEPTRS_PER_BLOCK(fs_info)); return eb_rewin; } /* * get_old_root() rewinds the state of @root's root node to the given @time_seq * value. If there are no changes, the current root->root_node is returned. If * anything changed in between, there's a fresh buffer allocated on which the * rewind operations are done. In any case, the returned buffer is read locked. * Returns NULL on error (with no locks held). */ static inline struct extent_buffer * get_old_root(struct btrfs_root *root, u64 time_seq) { struct btrfs_fs_info *fs_info = root->fs_info; struct tree_mod_elem *tm; struct extent_buffer *eb = NULL; struct extent_buffer *eb_root; u64 eb_root_owner = 0; struct extent_buffer *old; struct tree_mod_root *old_root = NULL; u64 old_generation = 0; u64 logical; int level; eb_root = btrfs_read_lock_root_node(root); tm = __tree_mod_log_oldest_root(eb_root, time_seq); if (!tm) return eb_root; if (tm->op == MOD_LOG_ROOT_REPLACE) { old_root = &tm->old_root; old_generation = tm->generation; logical = old_root->logical; level = old_root->level; } else { logical = eb_root->start; level = btrfs_header_level(eb_root); } tm = tree_mod_log_search(fs_info, logical, time_seq); if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) { btrfs_tree_read_unlock(eb_root); free_extent_buffer(eb_root); old = read_tree_block(fs_info, logical, 0, level, NULL); if (WARN_ON(IS_ERR(old) || !extent_buffer_uptodate(old))) { if (!IS_ERR(old)) free_extent_buffer(old); btrfs_warn(fs_info, "failed to read tree block %llu from get_old_root", logical); } else { eb = btrfs_clone_extent_buffer(old); free_extent_buffer(old); } } else if (old_root) { eb_root_owner = btrfs_header_owner(eb_root); btrfs_tree_read_unlock(eb_root); free_extent_buffer(eb_root); eb = alloc_dummy_extent_buffer(fs_info, logical); } else { btrfs_set_lock_blocking_read(eb_root); eb = btrfs_clone_extent_buffer(eb_root); btrfs_tree_read_unlock_blocking(eb_root); free_extent_buffer(eb_root); } if (!eb) return NULL; btrfs_tree_read_lock(eb); if (old_root) { btrfs_set_header_bytenr(eb, eb->start); btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV); btrfs_set_header_owner(eb, eb_root_owner); btrfs_set_header_level(eb, old_root->level); btrfs_set_header_generation(eb, old_generation); } if (tm) __tree_mod_log_rewind(fs_info, eb, time_seq, tm); else WARN_ON(btrfs_header_level(eb) != 0); WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(fs_info)); return eb; } int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq) { struct tree_mod_elem *tm; int level; struct extent_buffer *eb_root = btrfs_root_node(root); tm = __tree_mod_log_oldest_root(eb_root, time_seq); if (tm && tm->op == MOD_LOG_ROOT_REPLACE) { level = tm->old_root.level; } else { level = btrfs_header_level(eb_root); } free_extent_buffer(eb_root); return level; } 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_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 */ noinline 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) { struct btrfs_fs_info *fs_info = root->fs_info; u64 search_start; int ret; if (test_bit(BTRFS_ROOT_DELETING, &root->state)) btrfs_err(fs_info, "COW'ing blocks on a fs root that's being dropped"); if (trans->transaction != fs_info->running_transaction) WARN(1, KERN_CRIT "trans %llu running %llu\n", trans->transid, fs_info->running_transaction->transid); if (trans->transid != fs_info->generation) WARN(1, KERN_CRIT "trans %llu running %llu\n", trans->transid, fs_info->generation); if (!should_cow_block(trans, root, buf)) { trans->dirty = true; *cow_ret = buf; return 0; } search_start = buf->start & ~((u64)SZ_1G - 1); if (parent) btrfs_set_lock_blocking_write(parent); btrfs_set_lock_blocking_write(buf); /* * 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_cow_block(trans, root, buf, parent, parent_slot, cow_ret, search_start, 0); trace_btrfs_cow_block(root, buf, *cow_ret); return ret; } /* * helper function for defrag to decide if two blocks pointed to by a * node are actually close by */ static int close_blocks(u64 blocknr, u64 other, u32 blocksize) { if (blocknr < other && other - (blocknr + blocksize) < 32768) return 1; if (blocknr > other && blocknr - (other + blocksize) < 32768) return 1; return 0; } /* * compare two keys in a memcmp fashion */ static int comp_keys(const struct btrfs_disk_key *disk, const struct btrfs_key *k2) { struct btrfs_key k1; btrfs_disk_key_to_cpu(&k1, disk); return btrfs_comp_cpu_keys(&k1, k2); } /* * 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; } /* * this is used by the defrag code to go through all the * leaves pointed to by a node and reallocate them so that * disk order is close to key order */ int btrfs_realloc_node(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *parent, int start_slot, u64 *last_ret, struct btrfs_key *progress) { struct btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *cur; u64 blocknr; u64 gen; u64 search_start = *last_ret; u64 last_block = 0; u64 other; u32 parent_nritems; int end_slot; int i; int err = 0; int parent_level; int uptodate; u32 blocksize; int progress_passed = 0; struct btrfs_disk_key disk_key; parent_level = btrfs_header_level(parent); WARN_ON(trans->transaction != fs_info->running_transaction); WARN_ON(trans->transid != fs_info->generation); parent_nritems = btrfs_header_nritems(parent); blocksize = fs_info->nodesize; end_slot = parent_nritems - 1; if (parent_nritems <= 1) return 0; btrfs_set_lock_blocking_write(parent); for (i = start_slot; i <= end_slot; i++) { struct btrfs_key first_key; int close = 1; btrfs_node_key(parent, &disk_key, i); if (!progress_passed && comp_keys(&disk_key, progress) < 0) continue; progress_passed = 1; blocknr = btrfs_node_blockptr(parent, i); gen = btrfs_node_ptr_generation(parent, i); btrfs_node_key_to_cpu(parent, &first_key, i); if (last_block == 0) last_block = blocknr; if (i > 0) { other = btrfs_node_blockptr(parent, i - 1); close = close_blocks(blocknr, other, blocksize); } if (!close && i < end_slot) { other = btrfs_node_blockptr(parent, i + 1); close = close_blocks(blocknr, other, blocksize); } if (close) { last_block = blocknr; continue; } cur = find_extent_buffer(fs_info, blocknr); if (cur) uptodate = btrfs_buffer_uptodate(cur, gen, 0); else uptodate = 0; if (!cur || !uptodate) { if (!cur) { cur = read_tree_block(fs_info, blocknr, gen, parent_level - 1, &first_key); if (IS_ERR(cur)) { return PTR_ERR(cur); } else if (!extent_buffer_uptodate(cur)) { free_extent_buffer(cur); return -EIO; } } else if (!uptodate) { err = btrfs_read_buffer(cur, gen, parent_level - 1,&first_key); if (err) { free_extent_buffer(cur); return err; } } } if (search_start == 0) search_start = last_block; btrfs_tree_lock(cur); btrfs_set_lock_blocking_write(cur); err = __btrfs_cow_block(trans, root, cur, parent, i, &cur, search_start, min(16 * blocksize, (end_slot - i) * blocksize)); if (err) { btrfs_tree_unlock(cur); free_extent_buffer(cur); break; } search_start = cur->start; last_block = cur->start; *last_ret = search_start; btrfs_tree_unlock(cur); free_extent_buffer(cur); } return err; } /* * search for key in the extent_buffer. The items start at offset p, * and they are item_size apart. There are 'max' items in p. * * the slot in the array is returned via slot, and it points to * the place where you would insert key if it is not found in * the array. * * slot may point to max if the key is bigger than all of the keys */ static noinline int generic_bin_search(struct extent_buffer *eb, unsigned long p, int item_size, const struct btrfs_key *key, int max, int *slot) { int low = 0; int high = max; int mid; int ret; struct btrfs_disk_key *tmp = NULL; struct btrfs_disk_key unaligned; unsigned long offset; char *kaddr = NULL; unsigned long map_start = 0; unsigned long map_len = 0; int err; if (low > high) { btrfs_err(eb->fs_info, "%s: low (%d) > high (%d) eb %llu owner %llu level %d", __func__, low, high, eb->start, btrfs_header_owner(eb), btrfs_header_level(eb)); return -EINVAL; } while (low < high) { mid = (low + high) / 2; offset = p + mid * item_size; if (!kaddr || offset < map_start || (offset + sizeof(struct btrfs_disk_key)) > map_start + map_len) { err = map_private_extent_buffer(eb, offset, sizeof(struct btrfs_disk_key), &kaddr, &map_start, &map_len); if (!err) { tmp = (struct btrfs_disk_key *)(kaddr + offset - map_start); } else if (err == 1) { read_extent_buffer(eb, &unaligned, offset, sizeof(unaligned)); tmp = &unaligned; } else { return err; } } else { tmp = (struct btrfs_disk_key *)(kaddr + offset - map_start); } ret = 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; } /* * simple bin_search frontend that does the right thing for * leaves vs nodes */ int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key, int level, int *slot) { if (level == 0) return generic_bin_search(eb, offsetof(struct btrfs_leaf, items), sizeof(struct btrfs_item), key, btrfs_header_nritems(eb), slot); else return generic_bin_search(eb, offsetof(struct btrfs_node, ptrs), sizeof(struct btrfs_key_ptr), key, btrfs_header_nritems(eb), slot); } static void root_add_used(struct btrfs_root *root, u32 size) { spin_lock(&root->accounting_lock); btrfs_set_root_used(&root->root_item, btrfs_root_used(&root->root_item) + size); spin_unlock(&root->accounting_lock); } static void root_sub_used(struct btrfs_root *root, u32 size) { spin_lock(&root->accounting_lock); btrfs_set_root_used(&root->root_item, btrfs_root_used(&root->root_item) - size); 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 extent_buffer *eb; struct btrfs_key first_key; if (slot < 0 || slot >= btrfs_header_nritems(parent)) return ERR_PTR(-ENOENT); BUG_ON(level == 0); btrfs_node_key_to_cpu(parent, &first_key, slot); eb = read_tree_block(parent->fs_info, btrfs_node_blockptr(parent, slot), btrfs_node_ptr_generation(parent, slot), level - 1, &first_key); if (!IS_ERR(eb) && !extent_buffer_uptodate(eb)) { free_extent_buffer(eb); eb = 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 && path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING); 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); btrfs_handle_fs_error(fs_info, ret, NULL); goto enospc; } btrfs_tree_lock(child); btrfs_set_lock_blocking_write(child); ret = btrfs_cow_block(trans, root, child, mid, 0, &child); if (ret) { btrfs_tree_unlock(child); free_extent_buffer(child); goto enospc; } ret = tree_mod_log_insert_root(root->node, child, 1); BUG_ON(ret < 0); 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_clean_tree_block(mid); btrfs_tree_unlock(mid); /* once for the path */ free_extent_buffer(mid); root_sub_used(root, mid->len); btrfs_free_tree_block(trans, 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; left = btrfs_read_node_slot(parent, pslot - 1); if (IS_ERR(left)) left = NULL; if (left) { btrfs_tree_lock(left); btrfs_set_lock_blocking_write(left); wret = btrfs_cow_block(trans, root, left, parent, pslot - 1, &left); if (wret) { ret = wret; goto enospc; } } right = btrfs_read_node_slot(parent, pslot + 1); if (IS_ERR(right)) right = NULL; if (right) { btrfs_tree_lock(right); btrfs_set_lock_blocking_write(right); wret = btrfs_cow_block(trans, root, right, parent, pslot + 1, &right); if (wret) { ret = wret; goto enospc; } } /* 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_clean_tree_block(right); btrfs_tree_unlock(right); del_ptr(root, path, level + 1, pslot + 1); root_sub_used(root, right->len); btrfs_free_tree_block(trans, 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 = tree_mod_log_insert_key(parent, pslot + 1, MOD_LOG_KEY_REPLACE, GFP_NOFS); BUG_ON(ret < 0); btrfs_set_node_key(parent, &right_key, pslot + 1); btrfs_mark_buffer_dirty(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 (!left) { ret = -EROFS; btrfs_handle_fs_error(fs_info, ret, NULL); goto enospc; } wret = balance_node_right(trans, mid, left); if (wret < 0) { ret = wret; goto enospc; } 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_clean_tree_block(mid); btrfs_tree_unlock(mid); del_ptr(root, path, level + 1, pslot); root_sub_used(root, mid->len); btrfs_free_tree_block(trans, 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 = tree_mod_log_insert_key(parent, pslot, MOD_LOG_KEY_REPLACE, GFP_NOFS); BUG_ON(ret < 0); btrfs_set_node_key(parent, &mid_key, pslot); btrfs_mark_buffer_dirty(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(); enospc: 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; left = btrfs_read_node_slot(parent, pslot - 1); if (IS_ERR(left)) left = NULL; /* first, try to make some room in the middle buffer */ if (left) { u32 left_nr; btrfs_tree_lock(left); btrfs_set_lock_blocking_write(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); 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 = tree_mod_log_insert_key(parent, pslot, MOD_LOG_KEY_REPLACE, GFP_NOFS); BUG_ON(ret < 0); btrfs_set_node_key(parent, &disk_key, pslot); btrfs_mark_buffer_dirty(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); } right = btrfs_read_node_slot(parent, pslot + 1); if (IS_ERR(right)) right = NULL; /* * then try to empty the right most buffer into the middle */ if (right) { u32 right_nr; btrfs_tree_lock(right); btrfs_set_lock_blocking_write(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); 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 = tree_mod_log_insert_key(parent, pslot + 1, MOD_LOG_KEY_REPLACE, GFP_NOFS); BUG_ON(ret < 0); btrfs_set_node_key(parent, &disk_key, pslot + 1); btrfs_mark_buffer_dirty(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; struct extent_buffer *eb; u32 nr; u32 blocksize; u32 nscan = 0; if (level != 1) return; if (!path->nodes[level]) return; node = path->nodes[level]; search = btrfs_node_blockptr(node, slot); blocksize = fs_info->nodesize; 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) { 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 ((search <= target && target - search <= 65536) || (search > target && search - target <= 65536)) { readahead_tree_block(fs_info, search); nread += blocksize; } nscan++; if ((nread > 65536 || nscan > 32)) break; } } static noinline void reada_for_balance(struct btrfs_fs_info *fs_info, struct btrfs_path *path, int level) { int slot; int nritems; struct extent_buffer *parent; struct extent_buffer *eb; u64 gen; u64 block1 = 0; u64 block2 = 0; parent = path->nodes[level + 1]; if (!parent) return; nritems = btrfs_header_nritems(parent); slot = path->slots[level + 1]; if (slot > 0) { block1 = btrfs_node_blockptr(parent, slot - 1); gen = btrfs_node_ptr_generation(parent, slot - 1); eb = find_extent_buffer(fs_info, block1); /* * if we get -eagain from btrfs_buffer_uptodate, we * don't want to return eagain here. That will loop * forever */ if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0) block1 = 0; free_extent_buffer(eb); } if (slot + 1 < nritems) { block2 = btrfs_node_blockptr(parent, slot + 1); gen = btrfs_node_ptr_generation(parent, slot + 1); eb = find_extent_buffer(fs_info, block2); if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0) block2 = 0; free_extent_buffer(eb); } if (block1) readahead_tree_block(fs_info, block1); if (block2) readahead_tree_block(fs_info, block2); } /* * 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; int no_skips = 0; struct extent_buffer *t; for (i = level; i < BTRFS_MAX_LEVEL; i++) { if (!path->nodes[i]) break; if (!path->locks[i]) break; if (!no_skips && path->slots[i] == 0) { skip_level = i + 1; continue; } if (!no_skips && path->keep_locks) { u32 nritems; t = path->nodes[i]; nritems = btrfs_header_nritems(t); if (nritems < 1 || path->slots[i] >= nritems - 1) { skip_level = i + 1; continue; } } if (skip_level < i && i >= lowest_unlock) no_skips = 1; t = path->nodes[i]; if (i >= lowest_unlock && i > skip_level) { btrfs_tree_unlock_rw(t, 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. The goal is to find a block * in cache without setting the path to blocking. If we find the block * we return zero and the path is unchanged. * * If we can't find the block, we set the path blocking and do some * reada. -EAGAIN is returned and the search must be repeated. */ 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; u64 blocknr; u64 gen; struct extent_buffer *b = *eb_ret; struct extent_buffer *tmp; struct btrfs_key first_key; int ret; int parent_level; blocknr = btrfs_node_blockptr(b, slot); gen = btrfs_node_ptr_generation(b, slot); parent_level = btrfs_header_level(b); btrfs_node_key_to_cpu(b, &first_key, slot); tmp = find_extent_buffer(fs_info, blocknr); if (tmp) { /* 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, &first_key, gen)) { free_extent_buffer(tmp); return -EUCLEAN; } *eb_ret = tmp; return 0; } /* the pages were up to date, but we failed * the generation number check. Do a full * read for the generation number that is correct. * We must do this without dropping locks so * we can trust our generation number */ btrfs_set_path_blocking(p); /* now we're allowed to do a blocking uptodate check */ ret = btrfs_read_buffer(tmp, gen, parent_level - 1, &first_key); if (!ret) { *eb_ret = tmp; return 0; } free_extent_buffer(tmp); btrfs_release_path(p); return -EIO; } /* * reduce lock contention at high levels * of the btree by dropping locks before * we read. Don't release the lock on the current * level because we need to walk this node to figure * out which blocks to read. */ btrfs_unlock_up_safe(p, level + 1); btrfs_set_path_blocking(p); if (p->reada != READA_NONE) reada_for_search(fs_info, p, level, slot, key->objectid); ret = -EAGAIN; tmp = read_tree_block(fs_info, blocknr, gen, parent_level - 1, &first_key); if (!IS_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; free_extent_buffer(tmp); } else { ret = PTR_ERR(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; if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) { int sret; if (*write_lock_level < level + 1) { *write_lock_level = level + 1; btrfs_release_path(p); goto again; } btrfs_set_path_blocking(p); reada_for_balance(fs_info, p, level); sret = split_node(trans, root, p, level); BUG_ON(sret > 0); if (sret) { ret = sret; goto done; } b = p->nodes[level]; } else if (ins_len < 0 && btrfs_header_nritems(b) < BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 2) { int sret; if (*write_lock_level < level + 1) { *write_lock_level = level + 1; btrfs_release_path(p); goto again; } btrfs_set_path_blocking(p); reada_for_balance(fs_info, p, level); sret = balance_level(trans, root, p, level); if (sret) { ret = sret; goto done; } b = p->nodes[level]; if (!b) { btrfs_release_path(p); goto again; } BUG_ON(btrfs_header_nritems(b) == 1); } return 0; again: ret = -EAGAIN; done: return ret; } static int key_search(struct extent_buffer *b, const struct btrfs_key *key, int level, int *prev_cmp, int *slot) { if (*prev_cmp != 0) { *prev_cmp = btrfs_bin_search(b, key, level, slot); return *prev_cmp; } *slot = 0; return 0; } 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 btrfs_fs_info *fs_info = root->fs_info; struct extent_buffer *b; int root_lock; int level = 0; /* We try very hard to do read locks on the root */ root_lock = BTRFS_READ_LOCK; if (p->search_commit_root) { /* * The commit roots are read only so we always do read locks, * and we always must hold the commit_root_sem when doing * searches on them, the only exception is send where we don't * want to block transaction commits for a long time, so * we need to clone the commit root in order to avoid races * with transaction commits that create a snapshot of one of * the roots used by a send operation. */ if (p->need_commit_sem) { down_read(&fs_info->commit_root_sem); b = btrfs_clone_extent_buffer(root->commit_root); up_read(&fs_info->commit_root_sem); if (!b) return ERR_PTR(-ENOMEM); } else { 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; } /* * 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 */ 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: p->nodes[level] = b; if (!p->skip_locking) p->locks[level] = root_lock; /* * Callers are responsible for dropping b's references. */ return b; } /* * btrfs_search_slot - 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, for inserts it is 1, for * deletions it's -1. 0 for plain searches * @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 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; lowest_level = p->lowest_level; WARN_ON(lowest_level && ins_len > 0); WARN_ON(p->nodes[0] != NULL); BUG_ON(!cow && ins_len); 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; 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)) { trans->dirty = true; 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; } btrfs_set_path_blocking(p); if (last_level) err = btrfs_cow_block(trans, root, b, NULL, 0, &b); else err = btrfs_cow_block(trans, root, b, p->nodes[level + 1], p->slots[level + 1], &b); if (err) { ret = err; goto done; } } cow_done: p->nodes[level] = b; /* * Leave path with blocking locks to avoid massive * lock context switch, this is made on purpose. */ /* * 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; } } ret = key_search(b, key, level, &prev_cmp, &slot); if (ret < 0) goto done; if (level == 0) { p->slots[level] = slot; if (ins_len > 0 && btrfs_leaf_free_space(b) < ins_len) { if (write_lock_level < 1) { write_lock_level = 1; btrfs_release_path(p); goto again; } btrfs_set_path_blocking(p); err = split_leaf(trans, root, key, p, ins_len, ret == 0); BUG_ON(err > 0); if (err) { ret = err; goto done; } } if (!p->search_for_split) unlock_up(p, level, lowest_unlock, min_write_lock_level, NULL); goto done; } 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); if (level <= write_lock_level) { if (!btrfs_try_tree_write_lock(b)) { btrfs_set_path_blocking(p); btrfs_tree_lock(b); } p->locks[level] = BTRFS_WRITE_LOCK; } else { if (!btrfs_tree_read_lock_atomic(b)) { btrfs_set_path_blocking(p); btrfs_tree_read_lock(b); } p->locks[level] = BTRFS_READ_LOCK; } p->nodes[level] = b; } } ret = 1; done: /* * we don't really know what they plan on doing with the path * from here on, so for now just mark it as blocking */ if (!p->leave_spinning) btrfs_set_path_blocking(p); if (ret < 0 && !p->skip_release_on_error) btrfs_release_path(p); return ret; } /* * 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; int prev_cmp = -1; lowest_level = p->lowest_level; WARN_ON(p->nodes[0] != NULL); if (p->search_commit_root) { BUG_ON(time_seq); return btrfs_search_slot(NULL, root, key, p, 0, 0); } again: b = 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); /* * Since we can unwind ebs we want to do a real search every * time. */ prev_cmp = -1; ret = key_search(b, key, level, &prev_cmp, &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); if (!btrfs_tree_read_lock_atomic(b)) { btrfs_set_path_blocking(p); btrfs_tree_read_lock(b); } b = 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 (!p->leave_spinning) btrfs_set_path_blocking(p); if (ret < 0) btrfs_release_path(p); return ret; } /* * 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; } /* * 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_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 = tree_mod_log_insert_key(t, tslot, MOD_LOG_KEY_REPLACE, GFP_ATOMIC); BUG_ON(ret < 0); btrfs_set_node_key(t, key, tslot); btrfs_mark_buffer_dirty(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_fs_info *fs_info, struct btrfs_path *path, const struct btrfs_key *new_key) { 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(comp_keys(&disk_key, new_key) >= 0)) { 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); btrfs_print_leaf(eb); BUG(); } } if (slot < btrfs_header_nritems(eb) - 1) { btrfs_item_key(eb, &disk_key, slot + 1); if (unlikely(comp_keys(&disk_key, new_key) <= 0)) { 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); btrfs_print_leaf(eb); BUG(); } } btrfs_cpu_key_to_disk(&disk_key, new_key); btrfs_set_item_key(eb, &disk_key, slot); btrfs_mark_buffer_dirty(eb); if (slot == 0) fixup_low_keys(path, &disk_key, 1); } /* * 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); ret = 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_nritems), btrfs_node_key_ptr_offset(0), push_items * sizeof(struct btrfs_key_ptr)); if (push_items < src_nritems) { /* * Don't call tree_mod_log_insert_move here, key removal was * already fully logged by tree_mod_log_eb_copy above. */ memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0), btrfs_node_key_ptr_offset(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(src); btrfs_mark_buffer_dirty(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; ret = tree_mod_log_insert_move(dst, push_items, 0, dst_nritems); BUG_ON(ret < 0); memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items), btrfs_node_key_ptr_offset(0), (dst_nritems) * sizeof(struct btrfs_key_ptr)); ret = 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(0), btrfs_node_key_ptr_offset(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(src); btrfs_mark_buffer_dirty(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) { struct btrfs_fs_info *fs_info = root->fs_info; 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 = alloc_tree_block_no_bg_flush(trans, root, 0, &lower_key, level, root->node->start, 0); if (IS_ERR(c)) return PTR_ERR(c); root_add_used(root, fs_info->nodesize); 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(c); old = root->node; ret = tree_mod_log_insert_root(root->node, c, 0); BUG_ON(ret < 0); 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_BLOCKING; 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 void 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_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 = tree_mod_log_insert_move(lower, slot + 1, slot, nritems - slot); BUG_ON(ret < 0); } memmove_extent_buffer(lower, btrfs_node_key_ptr_offset(slot + 1), btrfs_node_key_ptr_offset(slot), (nritems - slot) * sizeof(struct btrfs_key_ptr)); } if (level) { ret = tree_mod_log_insert_key(lower, slot, MOD_LOG_KEY_ADD, GFP_NOFS); BUG_ON(ret < 0); } 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(lower); } /* * 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 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 = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, level, c->start, 0); if (IS_ERR(split)) return PTR_ERR(split); root_add_used(root, fs_info->nodesize); ASSERT(btrfs_header_level(c) == level); ret = tree_mod_log_eb_copy(split, c, 0, mid, c_nritems - mid); if (ret) { btrfs_abort_transaction(trans, ret); return ret; } copy_extent_buffer(split, c, btrfs_node_key_ptr_offset(0), btrfs_node_key_ptr_offset(mid), (c_nritems - mid) * sizeof(struct btrfs_key_ptr)); btrfs_set_header_nritems(split, c_nritems - mid); btrfs_set_header_nritems(c, mid); ret = 0; btrfs_mark_buffer_dirty(c); btrfs_mark_buffer_dirty(split); insert_ptr(trans, path, &disk_key, split->start, path->slots[level + 1] + 1, level + 1); 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 ret; } /* * 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(struct extent_buffer *l, int start, int nr) { struct btrfs_item *start_item; struct btrfs_item *end_item; struct btrfs_map_token token; int data_len; int nritems = btrfs_header_nritems(l); int end = min(nritems, start + nr) - 1; if (!nr) return 0; btrfs_init_map_token(&token, l); start_item = btrfs_item_nr(start); end_item = btrfs_item_nr(end); data_len = btrfs_token_item_offset(l, start_item, &token) + btrfs_token_item_size(l, start_item, &token); data_len = data_len - btrfs_token_item_offset(l, end_item, &token); 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 */ noinline int btrfs_leaf_free_space(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_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; struct btrfs_item *item; 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) { item = btrfs_item_nr(i); 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, item); if (this_item_size + sizeof(*item) + push_space > free_space) break; push_items++; push_space += this_item_size + sizeof(*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_end_nr(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_extent_buffer(right, BTRFS_LEAF_DATA_OFFSET + data_end - push_space, BTRFS_LEAF_DATA_OFFSET + data_end, BTRFS_LEAF_DATA_SIZE(fs_info) - data_end); /* copy from the left data area */ copy_extent_buffer(right, left, BTRFS_LEAF_DATA_OFFSET + BTRFS_LEAF_DATA_SIZE(fs_info) - push_space, BTRFS_LEAF_DATA_OFFSET + leaf_data_end(left), push_space); memmove_extent_buffer(right, btrfs_item_nr_offset(push_items), btrfs_item_nr_offset(0), right_nritems * sizeof(struct btrfs_item)); /* copy the items from left to right */ copy_extent_buffer(right, left, btrfs_item_nr_offset(0), btrfs_item_nr_offset(left_nritems - push_items), push_items * sizeof(struct btrfs_item)); /* 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++) { item = btrfs_item_nr(i); push_space -= btrfs_token_item_size(right, item, &token); btrfs_set_token_item_offset(right, item, push_space, &token); } left_nritems -= push_items; btrfs_set_header_nritems(left, left_nritems); if (left_nritems) btrfs_mark_buffer_dirty(left); else btrfs_clean_tree_block(left); btrfs_mark_buffer_dirty(right); btrfs_item_key(right, &disk_key, 0); btrfs_set_node_key(upper, &disk_key, slot + 1); btrfs_mark_buffer_dirty(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_clean_tree_block(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_locked(path->nodes[1]); right = btrfs_read_node_slot(upper, slot + 1); /* * slot + 1 is not valid or we fail to read the right node, * no big deal, just return. */ if (IS_ERR(right)) return 1; btrfs_tree_lock(right); btrfs_set_lock_blocking_write(right); free_space = btrfs_leaf_free_space(right); if (free_space < data_size) goto out_unlock; /* cow and double check */ ret = btrfs_cow_block(trans, root, right, upper, slot + 1, &right); if (ret) goto out_unlock; free_space = btrfs_leaf_free_space(right); if (free_space < data_size) goto out_unlock; left_nritems = btrfs_header_nritems(left); if (left_nritems == 0) goto out_unlock; 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(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_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; struct btrfs_item *item; 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++) { item = btrfs_item_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, item); if (this_item_size + sizeof(*item) + push_space > free_space) break; push_items++; push_space += this_item_size + sizeof(*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_extent_buffer(left, right, btrfs_item_nr_offset(btrfs_header_nritems(left)), btrfs_item_nr_offset(0), push_items * sizeof(struct btrfs_item)); push_space = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_offset_nr(right, push_items - 1); copy_extent_buffer(left, right, BTRFS_LEAF_DATA_OFFSET + leaf_data_end(left) - push_space, BTRFS_LEAF_DATA_OFFSET + btrfs_item_offset_nr(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_nr(left, old_left_nritems - 1); for (i = old_left_nritems; i < old_left_nritems + push_items; i++) { u32 ioff; item = btrfs_item_nr(i); ioff = btrfs_token_item_offset(left, item, &token); btrfs_set_token_item_offset(left, item, ioff - (BTRFS_LEAF_DATA_SIZE(fs_info) - old_left_item_size), &token); } 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_nr(right, push_items - 1) - leaf_data_end(right); memmove_extent_buffer(right, BTRFS_LEAF_DATA_OFFSET + BTRFS_LEAF_DATA_SIZE(fs_info) - push_space, BTRFS_LEAF_DATA_OFFSET + leaf_data_end(right), push_space); memmove_extent_buffer(right, btrfs_item_nr_offset(0), btrfs_item_nr_offset(push_items), (btrfs_header_nritems(right) - push_items) * sizeof(struct btrfs_item)); } 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++) { item = btrfs_item_nr(i); push_space = push_space - btrfs_token_item_size(right, item, &token); btrfs_set_token_item_offset(right, item, push_space, &token); } btrfs_mark_buffer_dirty(left); if (right_nritems) btrfs_mark_buffer_dirty(right); else btrfs_clean_tree_block(right); btrfs_item_key(right, &disk_key, 0); fixup_low_keys(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_locked(path->nodes[1]); left = btrfs_read_node_slot(path->nodes[1], slot - 1); /* * slot - 1 is not valid or we fail to read the left node, * no big deal, just return. */ if (IS_ERR(left)) return 1; btrfs_tree_lock(left); btrfs_set_lock_blocking_write(left); free_space = btrfs_leaf_free_space(left); if (free_space < data_size) { ret = 1; goto out; } /* cow and double check */ ret = btrfs_cow_block(trans, root, left, path->nodes[1], slot - 1, &left); if (ret) { /* we hit -ENOSPC, but it isn't fatal here */ if (ret == -ENOSPC) ret = 1; goto out; } free_space = btrfs_leaf_free_space(left); if (free_space < data_size) { ret = 1; goto out; } return __push_leaf_left(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 void 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; 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_end_nr(l, mid) - leaf_data_end(l); copy_extent_buffer(right, l, btrfs_item_nr_offset(0), btrfs_item_nr_offset(mid), nritems * sizeof(struct btrfs_item)); copy_extent_buffer(right, l, BTRFS_LEAF_DATA_OFFSET + BTRFS_LEAF_DATA_SIZE(fs_info) - data_copy_size, BTRFS_LEAF_DATA_OFFSET + leaf_data_end(l), data_copy_size); rt_data_off = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_end_nr(l, mid); btrfs_init_map_token(&token, right); for (i = 0; i < nritems; i++) { struct btrfs_item *item = btrfs_item_nr(i); u32 ioff; ioff = btrfs_token_item_offset(right, item, &token); btrfs_set_token_item_offset(right, item, ioff + rt_data_off, &token); } btrfs_set_header_nritems(l, mid); btrfs_item_key(right, &disk_key, 0); insert_ptr(trans, path, &disk_key, right->start, path->slots[1] + 1, 1); btrfs_mark_buffer_dirty(right); btrfs_mark_buffer_dirty(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); } /* * 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_nr(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); right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0, l->start, 0); if (IS_ERR(right)) return PTR_ERR(right); root_add_used(root, fs_info->nodesize); if (split == 0) { if (mid <= slot) { btrfs_set_header_nritems(right, 0); insert_ptr(trans, path, &disk_key, right->start, path->slots[1] + 1, 1); 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); insert_ptr(trans, path, &disk_key, right->start, path->slots[1], 1); 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(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; } copy_for_split(trans, path, l, right, slot, mid, nritems); 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_nr(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_nr(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; } btrfs_set_path_blocking(path); 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_path *path, const struct btrfs_key *new_key, unsigned long split_offset) { struct extent_buffer *leaf; struct btrfs_item *item; struct btrfs_item *new_item; int slot; char *buf; u32 nritems; u32 item_size; u32 orig_offset; struct btrfs_disk_key disk_key; leaf = path->nodes[0]; BUG_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item)); btrfs_set_path_blocking(path); item = btrfs_item_nr(path->slots[0]); orig_offset = btrfs_item_offset(leaf, item); item_size = btrfs_item_size(leaf, item); 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_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1), btrfs_item_nr_offset(slot), (nritems - slot) * sizeof(struct btrfs_item)); } btrfs_cpu_key_to_disk(&disk_key, new_key); btrfs_set_item_key(leaf, &disk_key, slot); new_item = btrfs_item_nr(slot); btrfs_set_item_offset(leaf, new_item, orig_offset); btrfs_set_item_size(leaf, new_item, item_size - split_offset); btrfs_set_item_offset(leaf, item, orig_offset + item_size - split_offset); btrfs_set_item_size(leaf, item, 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(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(path, new_key, split_offset); return ret; } /* * This function duplicate a 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 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_nr(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]++; setup_items_for_insert(root, path, new_key, &item_size, item_size, item_size + sizeof(struct btrfs_item), 1); 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; } /* * 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_path *path, u32 new_size, int from_end) { int slot; struct extent_buffer *leaf; struct btrfs_item *item; 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_nr(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_nr(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; item = btrfs_item_nr(i); ioff = btrfs_token_item_offset(leaf, item, &token); btrfs_set_token_item_offset(leaf, item, ioff + size_diff, &token); } /* shift the data */ if (from_end) { memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + data_end + size_diff, BTRFS_LEAF_DATA_OFFSET + 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_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + data_end + size_diff, BTRFS_LEAF_DATA_OFFSET + 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(path, &disk_key, 1); } item = btrfs_item_nr(slot); btrfs_set_item_size(leaf, item, new_size); btrfs_mark_buffer_dirty(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_path *path, u32 data_size) { int slot; struct extent_buffer *leaf; struct btrfs_item *item; 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_end_nr(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; item = btrfs_item_nr(i); ioff = btrfs_token_item_offset(leaf, item, &token); btrfs_set_token_item_offset(leaf, item, ioff - data_size, &token); } /* shift the data */ memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + data_end - data_size, BTRFS_LEAF_DATA_OFFSET + data_end, old_data - data_end); data_end = old_data; old_size = btrfs_item_size_nr(leaf, slot); item = btrfs_item_nr(slot); btrfs_set_item_size(leaf, item, old_size + data_size); btrfs_mark_buffer_dirty(leaf); if (btrfs_leaf_free_space(leaf) < 0) { btrfs_print_leaf(leaf); BUG(); } } /* * this is a helper for btrfs_insert_empty_items, the main goal here is * to save stack depth by doing the bulk of the work in a function * that doesn't call btrfs_search_slot */ void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path, const struct btrfs_key *cpu_key, u32 *data_size, u32 total_data, u32 total_size, int nr) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_item *item; 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; if (path->slots[0] == 0) { btrfs_cpu_key_to_disk(&disk_key, cpu_key); fixup_low_keys(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); 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_end_nr(leaf, slot); if (old_data < data_end) { btrfs_print_leaf(leaf); btrfs_crit(fs_info, "slot %d old_data %d data_end %d", 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; item = btrfs_item_nr(i); ioff = btrfs_token_item_offset(leaf, item, &token); btrfs_set_token_item_offset(leaf, item, ioff - total_data, &token); } /* shift the items */ memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr), btrfs_item_nr_offset(slot), (nritems - slot) * sizeof(struct btrfs_item)); /* shift the data */ memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + data_end - total_data, BTRFS_LEAF_DATA_OFFSET + data_end, old_data - data_end); data_end = old_data; } /* setup the item for the new data */ for (i = 0; i < nr; i++) { btrfs_cpu_key_to_disk(&disk_key, cpu_key + i); btrfs_set_item_key(leaf, &disk_key, slot + i); item = btrfs_item_nr(slot + i); btrfs_set_token_item_offset(leaf, item, data_end - data_size[i], &token); data_end -= data_size[i]; btrfs_set_token_item_size(leaf, item, data_size[i], &token); } btrfs_set_header_nritems(leaf, nritems + nr); btrfs_mark_buffer_dirty(leaf); if (btrfs_leaf_free_space(leaf) < 0) { btrfs_print_leaf(leaf); BUG(); } } /* * 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_key *cpu_key, u32 *data_size, int nr) { int ret = 0; int slot; int i; u32 total_size = 0; u32 total_data = 0; for (i = 0; i < nr; i++) total_data += data_size[i]; total_size = total_data + (nr * sizeof(struct btrfs_item)); ret = btrfs_search_slot(trans, root, cpu_key, 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(root, path, cpu_key, data_size, total_data, total_size, nr); 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(leaf); } btrfs_free_path(path); return ret; } /* * delete the pointer from a given node. * * the tree should have been previously balanced so the deletion does not * empty a node. */ static void del_ptr(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 = tree_mod_log_insert_move(parent, slot, slot + 1, nritems - slot - 1); BUG_ON(ret < 0); } memmove_extent_buffer(parent, btrfs_node_key_ptr_offset(slot), btrfs_node_key_ptr_offset(slot + 1), sizeof(struct btrfs_key_ptr) * (nritems - slot - 1)); } else if (level) { ret = tree_mod_log_insert_key(parent, slot, MOD_LOG_KEY_REMOVE, GFP_NOFS); BUG_ON(ret < 0); } 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(path, &disk_key, level + 1); } btrfs_mark_buffer_dirty(parent); } /* * 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 void btrfs_del_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_path *path, struct extent_buffer *leaf) { WARN_ON(btrfs_header_generation(leaf) != trans->transid); del_ptr(root, path, 1, path->slots[1]); /* * 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(root, leaf->len); atomic_inc(&leaf->refs); btrfs_free_tree_block(trans, root, leaf, 0, 1); free_extent_buffer_stale(leaf); } /* * 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; struct btrfs_item *item; u32 last_off; u32 dsize = 0; int ret = 0; int wret; int i; u32 nritems; leaf = path->nodes[0]; last_off = btrfs_item_offset_nr(leaf, slot + nr - 1); for (i = 0; i < nr; i++) dsize += btrfs_item_size_nr(leaf, slot + i); nritems = btrfs_header_nritems(leaf); if (slot + nr != nritems) { int data_end = leaf_data_end(leaf); struct btrfs_map_token token; memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + data_end + dsize, BTRFS_LEAF_DATA_OFFSET + data_end, last_off - data_end); btrfs_init_map_token(&token, leaf); for (i = slot + nr; i < nritems; i++) { u32 ioff; item = btrfs_item_nr(i); ioff = btrfs_token_item_offset(leaf, item, &token); btrfs_set_token_item_offset(leaf, item, ioff + dsize, &token); } memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot), btrfs_item_nr_offset(slot + nr), sizeof(struct btrfs_item) * (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_set_path_blocking(path); btrfs_clean_tree_block(leaf); btrfs_del_leaf(trans, root, path, leaf); } } 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(path, &disk_key, 1); } /* delete the leaf if it is mostly empty */ if (used < BTRFS_LEAF_DATA_SIZE(fs_info) / 3) { /* push_leaf_left fixes the path. * make sure the path still points to our leaf * for possible call to del_ptr below */ slot = path->slots[1]; atomic_inc(&leaf->refs); btrfs_set_path_blocking(path); wret = push_leaf_left(trans, root, path, 1, 1, 1, (u32)-1); if (wret < 0 && wret != -ENOSPC) ret = wret; if (path->nodes[0] == leaf && btrfs_header_nritems(leaf)) { wret = push_leaf_right(trans, root, path, 1, 1, 1, 0); if (wret < 0 && wret != -ENOSPC) ret = wret; } if (btrfs_header_nritems(leaf) == 0) { path->slots[1] = slot; btrfs_del_leaf(trans, root, path, leaf); 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(leaf); free_extent_buffer(leaf); } } else { btrfs_mark_buffer_dirty(leaf); } } return ret; } /* * search the tree again to find a leaf with lesser keys * returns 0 if it found something or 1 if there are no lesser leaves. * returns < 0 on io errors. * * This may release the path, and so you may lose any locks held at the * time you call it. */ int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) { struct btrfs_key key; struct btrfs_disk_key found_key; int ret; btrfs_item_key_to_cpu(path->nodes[0], &key, 0); 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; btrfs_item_key(path->nodes[0], &found_key, 0); ret = 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; } /* * 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; 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, min_key, level, &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, 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; btrfs_set_path_blocking(path); 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; } btrfs_set_path_blocking(path); 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); btrfs_set_path_blocking(path); 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; } /* * search the tree again to find a leaf with greater keys * returns 0 if it found something or 1 if there are no greater leaves. * returns < 0 on io errors. */ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path) { return btrfs_next_old_leaf(root, path, 0); } 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_key key; u32 nritems; int ret; int old_spinning = path->leave_spinning; int next_rw_lock = 0; 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; next_rw_lock = 0; btrfs_release_path(path); path->keep_locks = 1; path->leave_spinning = 1; if (time_seq) ret = btrfs_search_old_slot(root, &key, path, time_seq); else ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); path->keep_locks = 0; if (ret < 0) return ret; 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; } if (next) { btrfs_tree_unlock_rw(next, next_rw_lock); free_extent_buffer(next); } next = c; next_rw_lock = path->locks[level]; ret = read_block_for_search(root, path, &next, level, slot, &key); if (ret == -EAGAIN) goto again; if (ret < 0) { btrfs_release_path(path); goto done; } if (!path->skip_locking) { ret = btrfs_try_tree_read_lock(next); 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_set_path_blocking(path); btrfs_tree_read_lock(next); } next_rw_lock = BTRFS_READ_LOCK; } break; } path->slots[level] = slot; while (1) { level--; c = path->nodes[level]; if (path->locks[level]) btrfs_tree_unlock_rw(c, path->locks[level]); free_extent_buffer(c); path->nodes[level] = next; path->slots[level] = 0; if (!path->skip_locking) path->locks[level] = next_rw_lock; if (!level) break; ret = read_block_for_search(root, path, &next, level, 0, &key); if (ret == -EAGAIN) goto again; if (ret < 0) { btrfs_release_path(path); goto done; } if (!path->skip_locking) { ret = btrfs_try_tree_read_lock(next); if (!ret) { btrfs_set_path_blocking(path); btrfs_tree_read_lock(next); } next_rw_lock = BTRFS_READ_LOCK; } } ret = 0; done: unlock_up(path, 0, 1, 0, NULL); path->leave_spinning = old_spinning; if (!old_spinning) btrfs_set_path_blocking(path); return ret; } /* * 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) { btrfs_set_path_blocking(path); 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) { btrfs_set_path_blocking(path); 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; }
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