| /* |
| * Copyright (C) 2007,2008 Oracle. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public |
| * License v2 as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public |
| * License along with this program; if not, write to the |
| * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| * Boston, MA 021110-1307, USA. |
| */ |
| |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/rbtree.h> |
| #include "ctree.h" |
| #include "disk-io.h" |
| #include "transaction.h" |
| #include "print-tree.h" |
| #include "locking.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, 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 btrfs_root *root, struct extent_buffer *dst, |
| struct extent_buffer *src, int empty); |
| static int balance_node_right(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| 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 int tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, |
| struct extent_buffer *eb); |
| |
| struct btrfs_path *btrfs_alloc_path(void) |
| { |
| struct btrfs_path *path; |
| path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS); |
| return path; |
| } |
| |
| /* |
| * set all locked nodes in the path to blocking locks. This should |
| * be done before scheduling |
| */ |
| noinline void btrfs_set_path_blocking(struct btrfs_path *p) |
| { |
| int i; |
| for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
| if (!p->nodes[i] || !p->locks[i]) |
| continue; |
| btrfs_set_lock_blocking_rw(p->nodes[i], p->locks[i]); |
| if (p->locks[i] == BTRFS_READ_LOCK) |
| p->locks[i] = BTRFS_READ_LOCK_BLOCKING; |
| else if (p->locks[i] == BTRFS_WRITE_LOCK) |
| p->locks[i] = BTRFS_WRITE_LOCK_BLOCKING; |
| } |
| } |
| |
| /* |
| * reset all the locked nodes in the patch to spinning locks. |
| * |
| * held is used to keep lockdep happy, when lockdep is enabled |
| * we set held to a blocking lock before we go around and |
| * retake all the spinlocks in the path. You can safely use NULL |
| * for held |
| */ |
| noinline void btrfs_clear_path_blocking(struct btrfs_path *p, |
| struct extent_buffer *held, int held_rw) |
| { |
| int i; |
| |
| if (held) { |
| btrfs_set_lock_blocking_rw(held, held_rw); |
| if (held_rw == BTRFS_WRITE_LOCK) |
| held_rw = BTRFS_WRITE_LOCK_BLOCKING; |
| else if (held_rw == BTRFS_READ_LOCK) |
| held_rw = BTRFS_READ_LOCK_BLOCKING; |
| } |
| btrfs_set_path_blocking(p); |
| |
| for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) { |
| if (p->nodes[i] && p->locks[i]) { |
| btrfs_clear_lock_blocking_rw(p->nodes[i], p->locks[i]); |
| if (p->locks[i] == BTRFS_WRITE_LOCK_BLOCKING) |
| p->locks[i] = BTRFS_WRITE_LOCK; |
| else if (p->locks[i] == BTRFS_READ_LOCK_BLOCKING) |
| p->locks[i] = BTRFS_READ_LOCK; |
| } |
| } |
| |
| if (held) |
| btrfs_clear_lock_blocking_rw(held, held_rw); |
| } |
| |
| /* 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 cow'ed 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. |
| */ |
| static 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) |
| { |
| if (test_bit(BTRFS_ROOT_DIRTY, &root->state) || |
| !test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state)) |
| return; |
| |
| spin_lock(&root->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->objectid == BTRFS_EXTENT_TREE_OBJECTID) |
| list_move_tail(&root->dirty_list, |
| &root->fs_info->dirty_cowonly_roots); |
| else |
| list_move(&root->dirty_list, |
| &root->fs_info->dirty_cowonly_roots); |
| } |
| spin_unlock(&root->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 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 != root->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(cow, buf, 0, 0, cow->len); |
| 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(cow, root->fs_info->fsid, btrfs_header_fsid(), |
| BTRFS_FSID_SIZE); |
| |
| 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_move { |
| int dst_slot; |
| int nr_items; |
| }; |
| |
| struct tree_mod_root { |
| u64 logical; |
| u8 level; |
| }; |
| |
| struct tree_mod_elem { |
| struct rb_node node; |
| u64 index; /* shifted 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 tree_mod_move move; |
| |
| /* this is used for op == MOD_LOG_ROOT_REPLACE */ |
| struct tree_mod_root old_root; |
| }; |
| |
| static inline void tree_mod_log_read_lock(struct btrfs_fs_info *fs_info) |
| { |
| read_lock(&fs_info->tree_mod_log_lock); |
| } |
| |
| static inline void tree_mod_log_read_unlock(struct btrfs_fs_info *fs_info) |
| { |
| read_unlock(&fs_info->tree_mod_log_lock); |
| } |
| |
| static inline void tree_mod_log_write_lock(struct btrfs_fs_info *fs_info) |
| { |
| write_lock(&fs_info->tree_mod_log_lock); |
| } |
| |
| static inline void tree_mod_log_write_unlock(struct btrfs_fs_info *fs_info) |
| { |
| write_unlock(&fs_info->tree_mod_log_lock); |
| } |
| |
| /* |
| * 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) |
| { |
| tree_mod_log_write_lock(fs_info); |
| spin_lock(&fs_info->tree_mod_seq_lock); |
| if (!elem->seq) { |
| elem->seq = btrfs_inc_tree_mod_seq(fs_info); |
| list_add_tail(&elem->list, &fs_info->tree_mod_seq_list); |
| } |
| spin_unlock(&fs_info->tree_mod_seq_lock); |
| tree_mod_log_write_unlock(fs_info); |
| |
| 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; |
| |
| spin_lock(&fs_info->tree_mod_seq_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 |
| */ |
| spin_unlock(&fs_info->tree_mod_seq_lock); |
| return; |
| } |
| min_seq = cur_elem->seq; |
| } |
| } |
| spin_unlock(&fs_info->tree_mod_seq_lock); |
| |
| /* |
| * anything that's lower than the lowest existing (read: blocked) |
| * sequence number can be removed from the tree. |
| */ |
| tree_mod_log_write_lock(fs_info); |
| tm_root = &fs_info->tree_mod_log; |
| for (node = rb_first(tm_root); node; node = next) { |
| next = rb_next(node); |
| tm = container_of(node, struct tree_mod_elem, node); |
| if (tm->seq > min_seq) |
| continue; |
| rb_erase(node, tm_root); |
| kfree(tm); |
| } |
| tree_mod_log_write_unlock(fs_info); |
| } |
| |
| /* |
| * key order of the log: |
| * index -> sequence |
| * |
| * the index is the shifted logical of the *new* root node for root replace |
| * operations, or the shifted logical of the affected block for all other |
| * operations. |
| * |
| * Note: must be called with write lock (tree_mod_log_write_lock). |
| */ |
| 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; |
| |
| BUG_ON(!tm); |
| |
| tm->seq = btrfs_inc_tree_mod_seq(fs_info); |
| |
| tm_root = &fs_info->tree_mod_log; |
| new = &tm_root->rb_node; |
| while (*new) { |
| cur = container_of(*new, struct tree_mod_elem, node); |
| parent = *new; |
| if (cur->index < tm->index) |
| new = &((*new)->rb_left); |
| else if (cur->index > tm->index) |
| 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 |
| * call tree_mod_log_write_unlock() to release. |
| */ |
| 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; |
| |
| tree_mod_log_write_lock(fs_info); |
| if (list_empty(&(fs_info)->tree_mod_seq_list)) { |
| tree_mod_log_write_unlock(fs_info); |
| 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->index = eb->start >> PAGE_CACHE_SHIFT; |
| 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 btrfs_fs_info *fs_info, |
| 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(fs_info, eb)) |
| return 0; |
| |
| tm = alloc_tree_mod_elem(eb, slot, op, flags); |
| if (!tm) |
| return -ENOMEM; |
| |
| if (tree_mod_dont_log(fs_info, eb)) { |
| kfree(tm); |
| return 0; |
| } |
| |
| ret = __tree_mod_log_insert(fs_info, tm); |
| tree_mod_log_write_unlock(fs_info); |
| if (ret) |
| kfree(tm); |
| |
| return ret; |
| } |
| |
| static noinline int |
| tree_mod_log_insert_move(struct btrfs_fs_info *fs_info, |
| struct extent_buffer *eb, int dst_slot, int src_slot, |
| int nr_items, gfp_t flags) |
| { |
| 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(fs_info, eb)) |
| return 0; |
| |
| tm_list = kcalloc(nr_items, sizeof(struct tree_mod_elem *), flags); |
| if (!tm_list) |
| return -ENOMEM; |
| |
| tm = kzalloc(sizeof(*tm), flags); |
| if (!tm) { |
| ret = -ENOMEM; |
| goto free_tms; |
| } |
| |
| tm->index = eb->start >> PAGE_CACHE_SHIFT; |
| 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, flags); |
| if (!tm_list[i]) { |
| ret = -ENOMEM; |
| goto free_tms; |
| } |
| } |
| |
| if (tree_mod_dont_log(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(fs_info, tm_list[i]); |
| if (ret) |
| goto free_tms; |
| } |
| |
| ret = __tree_mod_log_insert(fs_info, tm); |
| if (ret) |
| goto free_tms; |
| tree_mod_log_write_unlock(fs_info); |
| 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, &fs_info->tree_mod_log); |
| kfree(tm_list[i]); |
| } |
| if (locked) |
| tree_mod_log_write_unlock(fs_info); |
| 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 btrfs_fs_info *fs_info, |
| struct extent_buffer *old_root, |
| struct extent_buffer *new_root, gfp_t flags, |
| int log_removal) |
| { |
| 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 *), |
| flags); |
| 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, flags); |
| if (!tm_list[i]) { |
| ret = -ENOMEM; |
| goto free_tms; |
| } |
| } |
| } |
| |
| tm = kzalloc(sizeof(*tm), flags); |
| if (!tm) { |
| ret = -ENOMEM; |
| goto free_tms; |
| } |
| |
| tm->index = new_root->start >> PAGE_CACHE_SHIFT; |
| 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); |
| |
| tree_mod_log_write_unlock(fs_info); |
| 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; |
| u64 index = start >> PAGE_CACHE_SHIFT; |
| |
| tree_mod_log_read_lock(fs_info); |
| tm_root = &fs_info->tree_mod_log; |
| node = tm_root->rb_node; |
| while (node) { |
| cur = container_of(node, struct tree_mod_elem, node); |
| if (cur->index < index) { |
| node = node->rb_left; |
| } else if (cur->index > index) { |
| 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; |
| } |
| } |
| tree_mod_log_read_unlock(fs_info); |
| |
| 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 btrfs_fs_info *fs_info, struct extent_buffer *dst, |
| struct extent_buffer *src, unsigned long dst_offset, |
| unsigned long src_offset, int nr_items) |
| { |
| 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; |
| } |
| |
| tree_mod_log_write_unlock(fs_info); |
| 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) |
| tree_mod_log_write_unlock(fs_info); |
| kfree(tm_list); |
| |
| return ret; |
| } |
| |
| static inline void |
| tree_mod_log_eb_move(struct btrfs_fs_info *fs_info, struct extent_buffer *dst, |
| int dst_offset, int src_offset, int nr_items) |
| { |
| int ret; |
| ret = tree_mod_log_insert_move(fs_info, dst, dst_offset, src_offset, |
| nr_items, GFP_NOFS); |
| BUG_ON(ret < 0); |
| } |
| |
| static noinline void |
| tree_mod_log_set_node_key(struct btrfs_fs_info *fs_info, |
| struct extent_buffer *eb, int slot, int atomic) |
| { |
| int ret; |
| |
| ret = tree_mod_log_insert_key(fs_info, eb, slot, |
| MOD_LOG_KEY_REPLACE, |
| atomic ? GFP_ATOMIC : GFP_NOFS); |
| BUG_ON(ret < 0); |
| } |
| |
| static noinline int |
| tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, 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(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(fs_info, eb)) |
| goto free_tms; |
| |
| ret = __tree_mod_log_free_eb(fs_info, tm_list, nritems); |
| tree_mod_log_write_unlock(fs_info); |
| 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; |
| } |
| |
| static noinline void |
| tree_mod_log_set_root_pointer(struct btrfs_root *root, |
| struct extent_buffer *new_root_node, |
| int log_removal) |
| { |
| int ret; |
| ret = tree_mod_log_insert_root(root->fs_info, root->node, |
| new_root_node, GFP_NOFS, log_removal); |
| BUG_ON(ret < 0); |
| } |
| |
| /* |
| * 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 refernece 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; |
| #ifdef BTRFS_COMPAT_EXTENT_TREE_V0 |
| if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) && |
| btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
| return 1; |
| #endif |
| 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) |
| { |
| 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, root, buf->start, |
| btrfs_header_level(buf), 1, |
| &refs, &flags); |
| if (ret) |
| return ret; |
| if (refs == 0) { |
| ret = -EROFS; |
| btrfs_std_error(root->fs_info, ret); |
| return ret; |
| } |
| } else { |
| refs = 1; |
| if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
| btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
| flags = BTRFS_BLOCK_FLAG_FULL_BACKREF; |
| else |
| flags = 0; |
| } |
| |
| owner = btrfs_header_owner(buf); |
| BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID && |
| !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); |
| |
| if (refs > 1) { |
| if ((owner == root->root_key.objectid || |
| root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && |
| !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) { |
| ret = btrfs_inc_ref(trans, root, buf, 1); |
| BUG_ON(ret); /* -ENOMEM */ |
| |
| if (root->root_key.objectid == |
| BTRFS_TREE_RELOC_OBJECTID) { |
| ret = btrfs_dec_ref(trans, root, buf, 0); |
| BUG_ON(ret); /* -ENOMEM */ |
| ret = btrfs_inc_ref(trans, root, cow, 1); |
| BUG_ON(ret); /* -ENOMEM */ |
| } |
| 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); |
| BUG_ON(ret); /* -ENOMEM */ |
| } |
| if (new_flags != 0) { |
| int level = btrfs_header_level(buf); |
| |
| ret = btrfs_set_disk_extent_flags(trans, root, |
| 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); |
| BUG_ON(ret); /* -ENOMEM */ |
| ret = btrfs_dec_ref(trans, root, buf, 1); |
| BUG_ON(ret); /* -ENOMEM */ |
| } |
| clean_tree_block(trans, root->fs_info, buf); |
| *last_ref = 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * does the dirty work in cow of a single block. The parent block (if |
| * supplied) is updated to point to the new cow copy. The new buffer is marked |
| * dirty and returned locked. If you modify the block it needs to be marked |
| * dirty again. |
| * |
| * search_start -- an allocation hint for the new block |
| * |
| * empty_size -- a hint that you plan on doing more cow. This is the size in |
| * bytes the allocator should try to find free next to the block it returns. |
| * This is just a hint and may be ignored by the allocator. |
| */ |
| 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_disk_key disk_key; |
| struct extent_buffer *cow; |
| int level, ret; |
| int last_ref = 0; |
| int unlock_orig = 0; |
| u64 parent_start; |
| |
| if (*cow_ret == buf) |
| unlock_orig = 1; |
| |
| btrfs_assert_tree_locked(buf); |
| |
| WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) && |
| trans->transid != root->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) { |
| if (parent) |
| parent_start = parent->start; |
| else |
| parent_start = 0; |
| } else |
| parent_start = 0; |
| |
| cow = btrfs_alloc_tree_block(trans, root, parent_start, |
| root->root_key.objectid, &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(cow, buf, 0, 0, cow->len); |
| 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(cow, root->fs_info->fsid, btrfs_header_fsid(), |
| BTRFS_FSID_SIZE); |
| |
| ret = update_ref_for_cow(trans, root, buf, cow, &last_ref); |
| if (ret) { |
| btrfs_abort_transaction(trans, root, ret); |
| return ret; |
| } |
| |
| if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) { |
| ret = btrfs_reloc_cow_block(trans, root, buf, cow); |
| if (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; |
| else |
| parent_start = 0; |
| |
| extent_buffer_get(cow); |
| tree_mod_log_set_root_pointer(root, cow, 1); |
| 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 { |
| if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) |
| parent_start = parent->start; |
| else |
| parent_start = 0; |
| |
| WARN_ON(trans->transid != btrfs_header_generation(parent)); |
| tree_mod_log_insert_key(root->fs_info, 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(root->fs_info, buf); |
| if (ret) { |
| btrfs_abort_transaction(trans, root, 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 btrfs_fs_info *fs_info, |
| 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 index of the *new* |
| * root, making it the very first operation that's logged for this root. |
| */ |
| while (1) { |
| tm = tree_mod_log_search_oldest(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 rewinded (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); |
| tree_mod_log_read_lock(fs_info); |
| 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 = container_of(next, struct tree_mod_elem, node); |
| if (tm->index != first_tm->index) |
| break; |
| } |
| tree_mod_log_read_unlock(fs_info); |
| btrfs_set_header_nritems(eb, n); |
| } |
| |
| /* |
| * Called with eb read locked. If the buffer cannot be rewinded, 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_rw(eb, BTRFS_READ_LOCK); |
| |
| 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_clear_path_blocking(path, NULL, BTRFS_READ_LOCK); |
| btrfs_tree_read_unlock_blocking(eb); |
| free_extent_buffer(eb); |
| |
| extent_buffer_get(eb_rewin); |
| 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->tree_root)); |
| |
| 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 tree_mod_elem *tm; |
| struct extent_buffer *eb = NULL; |
| struct extent_buffer *eb_root; |
| struct extent_buffer *old; |
| struct tree_mod_root *old_root = NULL; |
| u64 old_generation = 0; |
| u64 logical; |
| |
| eb_root = btrfs_read_lock_root_node(root); |
| tm = __tree_mod_log_oldest_root(root->fs_info, 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; |
| } else { |
| logical = eb_root->start; |
| } |
| |
| tm = tree_mod_log_search(root->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(root, logical, 0); |
| if (WARN_ON(!old || !extent_buffer_uptodate(old))) { |
| free_extent_buffer(old); |
| btrfs_warn(root->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) { |
| btrfs_tree_read_unlock(eb_root); |
| free_extent_buffer(eb_root); |
| eb = alloc_dummy_extent_buffer(root->fs_info, logical); |
| } else { |
| btrfs_set_lock_blocking_rw(eb_root, BTRFS_READ_LOCK); |
| eb = btrfs_clone_extent_buffer(eb_root); |
| btrfs_tree_read_unlock_blocking(eb_root); |
| free_extent_buffer(eb_root); |
| } |
| |
| if (!eb) |
| return NULL; |
| extent_buffer_get(eb); |
| 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, btrfs_header_owner(eb_root)); |
| btrfs_set_header_level(eb, old_root->level); |
| btrfs_set_header_generation(eb, old_generation); |
| } |
| if (tm) |
| __tree_mod_log_rewind(root->fs_info, eb, time_seq, tm); |
| else |
| WARN_ON(btrfs_header_level(eb) != 0); |
| WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(root)); |
| |
| 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(root->fs_info, 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_test_is_dummy_root(root)) |
| return 0; |
| |
| /* ensure we can see the force_cow */ |
| smp_rmb(); |
| |
| /* |
| * 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 commiting the transaction, |
| * after we've finished coping 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 cow'd 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) |
| { |
| u64 search_start; |
| int ret; |
| |
| if (trans->transaction != root->fs_info->running_transaction) |
| WARN(1, KERN_CRIT "trans %llu running %llu\n", |
| trans->transid, |
| root->fs_info->running_transaction->transid); |
| |
| if (trans->transid != root->fs_info->generation) |
| WARN(1, KERN_CRIT "trans %llu running %llu\n", |
| trans->transid, root->fs_info->generation); |
| |
| if (!should_cow_block(trans, root, buf)) { |
| *cow_ret = buf; |
| return 0; |
| } |
| |
| search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1); |
| |
| if (parent) |
| btrfs_set_lock_blocking(parent); |
| btrfs_set_lock_blocking(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(struct btrfs_disk_key *disk, 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 btrfs_comp_cpu_keys(struct btrfs_key *k1, 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 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 != root->fs_info->running_transaction); |
| WARN_ON(trans->transid != root->fs_info->generation); |
| |
| parent_nritems = btrfs_header_nritems(parent); |
| blocksize = root->nodesize; |
| end_slot = parent_nritems - 1; |
| |
| if (parent_nritems <= 1) |
| return 0; |
| |
| btrfs_set_lock_blocking(parent); |
| |
| for (i = start_slot; i <= end_slot; i++) { |
| 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); |
| 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 = btrfs_find_tree_block(root->fs_info, blocknr); |
| if (cur) |
| uptodate = btrfs_buffer_uptodate(cur, gen, 0); |
| else |
| uptodate = 0; |
| if (!cur || !uptodate) { |
| if (!cur) { |
| cur = read_tree_block(root, blocknr, gen); |
| if (!cur || !extent_buffer_uptodate(cur)) { |
| free_extent_buffer(cur); |
| return -EIO; |
| } |
| } else if (!uptodate) { |
| err = btrfs_read_buffer(cur, gen); |
| if (err) { |
| free_extent_buffer(cur); |
| return err; |
| } |
| } |
| } |
| if (search_start == 0) |
| search_start = last_block; |
| |
| btrfs_tree_lock(cur); |
| btrfs_set_lock_blocking(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; |
| } |
| |
| /* |
| * The leaf data grows from end-to-front in the node. |
| * this returns the address of the start of the last item, |
| * which is the stop of the leaf data stack |
| */ |
| static inline unsigned int leaf_data_end(struct btrfs_root *root, |
| struct extent_buffer *leaf) |
| { |
| u32 nr = btrfs_header_nritems(leaf); |
| if (nr == 0) |
| return BTRFS_LEAF_DATA_SIZE(root); |
| return btrfs_item_offset_nr(leaf, nr - 1); |
| } |
| |
| |
| /* |
| * 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, 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; |
| |
| 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 { |
| read_extent_buffer(eb, &unaligned, |
| offset, sizeof(unaligned)); |
| tmp = &unaligned; |
| } |
| |
| } 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 |
| */ |
| static int bin_search(struct extent_buffer *eb, 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); |
| } |
| |
| int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key, |
| int level, int *slot) |
| { |
| return bin_search(eb, key, level, 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). |
| * NULL is returned on error. |
| */ |
| static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root, |
| struct extent_buffer *parent, int slot) |
| { |
| int level = btrfs_header_level(parent); |
| struct extent_buffer *eb; |
| |
| if (slot < 0) |
| return NULL; |
| if (slot >= btrfs_header_nritems(parent)) |
| return NULL; |
| |
| BUG_ON(level == 0); |
| |
| eb = read_tree_block(root, btrfs_node_blockptr(parent, slot), |
| btrfs_node_ptr_generation(parent, slot)); |
| if (eb && !extent_buffer_uptodate(eb)) { |
| free_extent_buffer(eb); |
| eb = NULL; |
| } |
| |
| 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 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; |
| |
| if (level == 0) |
| return 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 = read_node_slot(root, mid, 0); |
| if (!child) { |
| ret = -EROFS; |
| btrfs_std_error(root->fs_info, ret); |
| goto enospc; |
| } |
| |
| btrfs_tree_lock(child); |
| btrfs_set_lock_blocking(child); |
| ret = btrfs_cow_block(trans, root, child, mid, 0, &child); |
| if (ret) { |
| btrfs_tree_unlock(child); |
| free_extent_buffer(child); |
| goto enospc; |
| } |
| |
| tree_mod_log_set_root_pointer(root, child, 1); |
| rcu_assign_pointer(root->node, child); |
| |
| add_root_to_dirty_list(root); |
| btrfs_tree_unlock(child); |
| |
| path->locks[level] = 0; |
| path->nodes[level] = NULL; |
| clean_tree_block(trans, root->fs_info, 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(root) / 4) |
| return 0; |
| |
| left = read_node_slot(root, parent, pslot - 1); |
| if (left) { |
| btrfs_tree_lock(left); |
| btrfs_set_lock_blocking(left); |
| wret = btrfs_cow_block(trans, root, left, |
| parent, pslot - 1, &left); |
| if (wret) { |
| ret = wret; |
| goto enospc; |
| } |
| } |
| right = read_node_slot(root, parent, pslot + 1); |
| if (right) { |
| btrfs_tree_lock(right); |
| btrfs_set_lock_blocking(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, root, 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, root, mid, right, 1); |
| if (wret < 0 && wret != -ENOSPC) |
| ret = wret; |
| if (btrfs_header_nritems(right) == 0) { |
| clean_tree_block(trans, root->fs_info, 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); |
| tree_mod_log_set_node_key(root->fs_info, parent, |
| pslot + 1, 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_std_error(root->fs_info, ret); |
| goto enospc; |
| } |
| wret = balance_node_right(trans, root, mid, left); |
| if (wret < 0) { |
| ret = wret; |
| goto enospc; |
| } |
| if (wret == 1) { |
| wret = push_node_left(trans, root, left, mid, 1); |
| if (wret < 0) |
| ret = wret; |
| } |
| BUG_ON(wret == 1); |
| } |
| if (btrfs_header_nritems(mid) == 0) { |
| clean_tree_block(trans, root->fs_info, 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); |
| tree_mod_log_set_node_key(root->fs_info, parent, |
| pslot, 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) { |
| extent_buffer_get(left); |
| /* 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 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 = read_node_slot(root, parent, pslot - 1); |
| |
| /* first, try to make some room in the middle buffer */ |
| if (left) { |
| u32 left_nr; |
| |
| btrfs_tree_lock(left); |
| btrfs_set_lock_blocking(left); |
| |
| left_nr = btrfs_header_nritems(left); |
| if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 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, root, |
| 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); |
| tree_mod_log_set_node_key(root->fs_info, parent, |
| pslot, 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 = read_node_slot(root, parent, pslot + 1); |
| |
| /* |
| * then try to empty the right most buffer into the middle |
| */ |
| if (right) { |
| u32 right_nr; |
| |
| btrfs_tree_lock(right); |
| btrfs_set_lock_blocking(right); |
| |
| right_nr = btrfs_header_nritems(right); |
| if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 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, root, |
| right, mid); |
| } |
| } |
| if (wret < 0) |
| ret = wret; |
| if (wret == 0) { |
| struct btrfs_disk_key disk_key; |
| |
| btrfs_node_key(right, &disk_key, 0); |
| tree_mod_log_set_node_key(root->fs_info, parent, |
| pslot + 1, 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_root *root, |
| struct btrfs_path *path, |
| int level, int slot, u64 objectid) |
| { |
| struct extent_buffer *node; |
| struct btrfs_disk_key disk_key; |
| u32 nritems; |
| u64 search; |
| u64 target; |
| u64 nread = 0; |
| u64 gen; |
| int direction = path->reada; |
| 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 = root->nodesize; |
| eb = btrfs_find_tree_block(root->fs_info, search); |
| if (eb) { |
| free_extent_buffer(eb); |
| return; |
| } |
| |
| target = search; |
| |
| nritems = btrfs_header_nritems(node); |
| nr = slot; |
| |
| while (1) { |
| if (direction < 0) { |
| if (nr == 0) |
| break; |
| nr--; |
| } else if (direction > 0) { |
| nr++; |
| if (nr >= nritems) |
| break; |
| } |
| if (path->reada < 0 && 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)) { |
| gen = btrfs_node_ptr_generation(node, nr); |
| readahead_tree_block(root, search); |
| nread += blocksize; |
| } |
| nscan++; |
| if ((nread > 65536 || nscan > 32)) |
| break; |
| } |
| } |
| |
| static noinline void reada_for_balance(struct btrfs_root *root, |
| 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 = btrfs_find_tree_block(root->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 = btrfs_find_tree_block(root->fs_info, block2); |
| if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0) |
| block2 = 0; |
| free_extent_buffer(eb); |
| } |
| |
| if (block1) |
| readahead_tree_block(root, block1); |
| if (block2) |
| readahead_tree_block(root, 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 && path->locks[i]) { |
| 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; |
| } |
| } |
| } |
| } |
| |
| /* |
| * This releases any locks held in the path starting at level and |
| * going all the way up to the root. |
| * |
| * btrfs_search_slot will keep the lock held on higher nodes in a few |
| * corner cases, such as COW of the block at slot zero in the node. This |
| * ignores those rules, and it should only be called when there are no |
| * more updates to be done higher up in the tree. |
| */ |
| noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level) |
| { |
| int i; |
| |
| if (path->keep_locks) |
| return; |
| |
| for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| if (!path->nodes[i]) |
| continue; |
| if (!path->locks[i]) |
| continue; |
| btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]); |
| path->locks[i] = 0; |
| } |
| } |
| |
| /* |
| * 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_trans_handle *trans, |
| struct btrfs_root *root, struct btrfs_path *p, |
| struct extent_buffer **eb_ret, int level, int slot, |
| struct btrfs_key *key, u64 time_seq) |
| { |
| u64 blocknr; |
| u64 gen; |
| struct extent_buffer *b = *eb_ret; |
| struct extent_buffer *tmp; |
| int ret; |
| |
| blocknr = btrfs_node_blockptr(b, slot); |
| gen = btrfs_node_ptr_generation(b, slot); |
| |
| tmp = btrfs_find_tree_block(root->fs_info, blocknr); |
| if (tmp) { |
| /* first we do an atomic uptodate check */ |
| if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) { |
| *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); |
| 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); |
| |
| free_extent_buffer(tmp); |
| if (p->reada) |
| reada_for_search(root, p, level, slot, key->objectid); |
| |
| btrfs_release_path(p); |
| |
| ret = -EAGAIN; |
| tmp = read_tree_block(root, blocknr, 0); |
| if (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 (!btrfs_buffer_uptodate(tmp, 0, 0)) |
| ret = -EIO; |
| free_extent_buffer(tmp); |
| } |
| 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) |
| { |
| int ret; |
| if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >= |
| BTRFS_NODEPTRS_PER_BLOCK(root) - 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(root, p, level); |
| sret = split_node(trans, root, p, level); |
| btrfs_clear_path_blocking(p, NULL, 0); |
| |
| 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(root) / 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(root, p, level); |
| sret = balance_level(trans, root, p, level); |
| btrfs_clear_path_blocking(p, NULL, 0); |
| |
| 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 void key_search_validate(struct extent_buffer *b, |
| struct btrfs_key *key, |
| int level) |
| { |
| #ifdef CONFIG_BTRFS_ASSERT |
| struct btrfs_disk_key disk_key; |
| |
| btrfs_cpu_key_to_disk(&disk_key, key); |
| |
| if (level == 0) |
| ASSERT(!memcmp_extent_buffer(b, &disk_key, |
| offsetof(struct btrfs_leaf, items[0].key), |
| sizeof(disk_key))); |
| else |
| ASSERT(!memcmp_extent_buffer(b, &disk_key, |
| offsetof(struct btrfs_node, ptrs[0].key), |
| sizeof(disk_key))); |
| #endif |
| } |
| |
| static int key_search(struct extent_buffer *b, struct btrfs_key *key, |
| int level, int *prev_cmp, int *slot) |
| { |
| if (*prev_cmp != 0) { |
| *prev_cmp = bin_search(b, key, level, slot); |
| return *prev_cmp; |
| } |
| |
| key_search_validate(b, key, level); |
| *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; |
| } |
| |
| /* |
| * look for key in the tree. path is filled in with nodes along the way |
| * if key is found, we return zero and you can find the item in the leaf |
| * level of the path (level 0) |
| * |
| * If the key isn't found, the path points to the slot where it should |
| * be inserted, and 1 is returned. If there are other errors during the |
| * search a negative error number is returned. |
| * |
| * 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) |
| */ |
| int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, 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; |
| int root_lock; |
| /* 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; |
| /* |
| * we try very hard to do read locks on the root |
| */ |
| root_lock = BTRFS_READ_LOCK; |
| level = 0; |
| if (p->search_commit_root) { |
| /* |
| * the commit roots are read only |
| * so we always do read locks |
| */ |
| if (p->need_commit_sem) |
| down_read(&root->fs_info->commit_root_sem); |
| b = root->commit_root; |
| extent_buffer_get(b); |
| level = btrfs_header_level(b); |
| if (p->need_commit_sem) |
| up_read(&root->fs_info->commit_root_sem); |
| if (!p->skip_locking) |
| btrfs_tree_read_lock(b); |
| } else { |
| if (p->skip_locking) { |
| b = btrfs_root_node(root); |
| level = btrfs_header_level(b); |
| } else { |
| /* 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) { |
| /* 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); |
| } |
| } |
| } |
| p->nodes[level] = b; |
| if (!p->skip_locking) |
| p->locks[level] = root_lock; |
| |
| while (b) { |
| level = btrfs_header_level(b); |
| |
| /* |
| * setup the path here so we can release it under lock |
| * contention with the cow code |
| */ |
| if (cow) { |
| /* |
| * if we don't really need to cow this block |
| * then we don't want to set the path blocking, |
| * so we test it here |
| */ |
| if (!should_cow_block(trans, root, b)) |
| goto cow_done; |
| |
| /* |
| * must have write locks on this node and the |
| * parent |
| */ |
| if (level > write_lock_level || |
| (level + 1 > write_lock_level && |
| level + 1 < BTRFS_MAX_LEVEL && |
| p->nodes[level + 1])) { |
| write_lock_level = level + 1; |
| btrfs_release_path(p); |
| goto again; |
| } |
| |
| btrfs_set_path_blocking(p); |
| 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; |
| btrfs_clear_path_blocking(p, NULL, 0); |
| |
| /* |
| * 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 (level != 0) { |
| int dec = 0; |
| if (ret && slot > 0) { |
| dec = 1; |
| slot -= 1; |
| } |
| 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(trans, root, p, |
| &b, level, slot, key, 0); |
| 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) { |
| err = btrfs_try_tree_write_lock(b); |
| if (!err) { |
| btrfs_set_path_blocking(p); |
| btrfs_tree_lock(b); |
| btrfs_clear_path_blocking(p, b, |
| BTRFS_WRITE_LOCK); |
| } |
| p->locks[level] = BTRFS_WRITE_LOCK; |
| } else { |
| err = btrfs_tree_read_lock_atomic(b); |
| if (!err) { |
| btrfs_set_path_blocking(p); |
| btrfs_tree_read_lock(b); |
| btrfs_clear_path_blocking(p, b, |
| BTRFS_READ_LOCK); |
| } |
| p->locks[level] = BTRFS_READ_LOCK; |
| } |
| p->nodes[level] = b; |
| } |
| } else { |
| p->slots[level] = slot; |
| if (ins_len > 0 && |
| btrfs_leaf_free_space(root, 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); |
| btrfs_clear_path_blocking(p, NULL, 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, &write_lock_level); |
| goto done; |
| } |
| } |
| 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, struct btrfs_key *key, |
| struct btrfs_path *p, u64 time_seq) |
| { |
| 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); |
| level = btrfs_header_level(b); |
| p->locks[level] = BTRFS_READ_LOCK; |
| |
| while (b) { |
| level = btrfs_header_level(b); |
| p->nodes[level] = b; |
| btrfs_clear_path_blocking(p, NULL, 0); |
| |
| /* |
| * 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 eb's we want to do a real search every |
| * time. |
| */ |
| prev_cmp = -1; |
| ret = key_search(b, key, level, &prev_cmp, &slot); |
| |
| if (level != 0) { |
| int dec = 0; |
| if (ret && slot > 0) { |
| dec = 1; |
| slot -= 1; |
| } |
| 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(NULL, root, p, &b, level, |
| slot, key, time_seq); |
| if (err == -EAGAIN) |
| goto again; |
| if (err) { |
| ret = err; |
| goto done; |
| } |
| |
| level = btrfs_header_level(b); |
| err = btrfs_tree_read_lock_atomic(b); |
| if (!err) { |
| btrfs_set_path_blocking(p); |
| btrfs_tree_read_lock(b); |
| btrfs_clear_path_blocking(p, b, |
| BTRFS_READ_LOCK); |
| } |
| b = tree_mod_log_rewind(root->fs_info, p, b, time_seq); |
| if (!b) { |
| ret = -ENOMEM; |
| goto done; |
| } |
| p->locks[level] = BTRFS_READ_LOCK; |
| p->nodes[level] = b; |
| } else { |
| p->slots[level] = slot; |
| unlock_up(p, level, lowest_unlock, 0, NULL); |
| goto done; |
| } |
| } |
| 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, |
| 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_fs_info *fs_info, |
| struct btrfs_path *path, |
| struct btrfs_disk_key *key, int level) |
| { |
| int i; |
| struct extent_buffer *t; |
| |
| for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| int tslot = path->slots[i]; |
| if (!path->nodes[i]) |
| break; |
| t = path->nodes[i]; |
| tree_mod_log_set_node_key(fs_info, t, tslot, 1); |
| 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, |
| 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); |
| BUG_ON(comp_keys(&disk_key, new_key) >= 0); |
| } |
| if (slot < btrfs_header_nritems(eb) - 1) { |
| btrfs_item_key(eb, &disk_key, slot + 1); |
| BUG_ON(comp_keys(&disk_key, new_key) <= 0); |
| } |
| |
| 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(fs_info, 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 btrfs_root *root, struct extent_buffer *dst, |
| struct extent_buffer *src, int empty) |
| { |
| 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(root) - 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(root->fs_info, dst, src, dst_nritems, 0, |
| push_items); |
| if (ret) { |
| btrfs_abort_transaction(trans, root, 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_eb_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 btrfs_root *root, |
| struct extent_buffer *dst, |
| struct extent_buffer *src) |
| { |
| 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(root) - 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; |
| |
| tree_mod_log_eb_move(root->fs_info, dst, push_items, 0, dst_nritems); |
| 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(root->fs_info, dst, src, 0, |
| src_nritems - push_items, push_items); |
| if (ret) { |
| btrfs_abort_transaction(trans, root, 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) |
| { |
| u64 lower_gen; |
| struct extent_buffer *lower; |
| struct extent_buffer *c; |
| struct extent_buffer *old; |
| struct btrfs_disk_key lower_key; |
| |
| BUG_ON(path->nodes[level]); |
| BUG_ON(path->nodes[level-1] != root->node); |
| |
| lower = path->nodes[level-1]; |
| if (level == 1) |
| btrfs_item_key(lower, &lower_key, 0); |
| else |
| btrfs_node_key(lower, &lower_key, 0); |
| |
| c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, |
| &lower_key, level, root->node->start, 0); |
| if (IS_ERR(c)) |
| return PTR_ERR(c); |
| |
| root_add_used(root, root->nodesize); |
| |
| memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header)); |
| btrfs_set_header_nritems(c, 1); |
| btrfs_set_header_level(c, level); |
| btrfs_set_header_bytenr(c, c->start); |
| btrfs_set_header_generation(c, trans->transid); |
| btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV); |
| btrfs_set_header_owner(c, root->root_key.objectid); |
| |
| write_extent_buffer(c, root->fs_info->fsid, btrfs_header_fsid(), |
| BTRFS_FSID_SIZE); |
| |
| write_extent_buffer(c, root->fs_info->chunk_tree_uuid, |
| btrfs_header_chunk_tree_uuid(c), BTRFS_UUID_SIZE); |
| |
| 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; |
| tree_mod_log_set_root_pointer(root, c, 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); |
| extent_buffer_get(c); |
| 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_root *root, 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(root)); |
| if (slot != nritems) { |
| if (level) |
| tree_mod_log_eb_move(root->fs_info, lower, slot + 1, |
| slot, nritems - slot); |
| 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(root->fs_info, 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 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(root) - 3) |
| return 0; |
| if (ret < 0) |
| return ret; |
| } |
| |
| c_nritems = btrfs_header_nritems(c); |
| mid = (c_nritems + 1) / 2; |
| btrfs_node_key(c, &disk_key, mid); |
| |
| split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, |
| &disk_key, level, c->start, 0); |
| if (IS_ERR(split)) |
| return PTR_ERR(split); |
| |
| root_add_used(root, root->nodesize); |
| |
| memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header)); |
| btrfs_set_header_level(split, btrfs_header_level(c)); |
| btrfs_set_header_bytenr(split, split->start); |
| btrfs_set_header_generation(split, trans->transid); |
| btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV); |
| btrfs_set_header_owner(split, root->root_key.objectid); |
| write_extent_buffer(split, root->fs_info->fsid, |
| btrfs_header_fsid(), BTRFS_FSID_SIZE); |
| write_extent_buffer(split, root->fs_info->chunk_tree_uuid, |
| btrfs_header_chunk_tree_uuid(split), |
| BTRFS_UUID_SIZE); |
| |
| ret = tree_mod_log_eb_copy(root->fs_info, split, c, 0, |
| mid, c_nritems - mid); |
| if (ret) { |
| btrfs_abort_transaction(trans, root, 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, root, 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); |
| 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 btrfs_root *root, |
| struct extent_buffer *leaf) |
| { |
| int nritems = btrfs_header_nritems(leaf); |
| int ret; |
| ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems); |
| if (ret < 0) { |
| btrfs_crit(root->fs_info, |
| "leaf free space ret %d, leaf data size %lu, used %d nritems %d", |
| ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root), |
| leaf_space_used(leaf, 0, nritems), nritems); |
| } |
| return ret; |
| } |
| |
| /* |
| * min slot controls the lowest index we're willing to push to the |
| * right. We'll push up to and including min_slot, but no lower |
| */ |
| static noinline int __push_leaf_right(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct btrfs_path *path, |
| int data_size, int empty, |
| struct extent_buffer *right, |
| int free_space, u32 left_nritems, |
| u32 min_slot) |
| { |
| 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; |
| |
| btrfs_init_map_token(&token); |
| |
| 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(root, 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(root, left); |
| |
| /* make room in the right data area */ |
| data_end = leaf_data_end(root, right); |
| memmove_extent_buffer(right, |
| btrfs_leaf_data(right) + data_end - push_space, |
| btrfs_leaf_data(right) + data_end, |
| BTRFS_LEAF_DATA_SIZE(root) - data_end); |
| |
| /* copy from the left data area */ |
| copy_extent_buffer(right, left, btrfs_leaf_data(right) + |
| BTRFS_LEAF_DATA_SIZE(root) - push_space, |
| btrfs_leaf_data(left) + leaf_data_end(root, 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 */ |
| right_nritems += push_items; |
| btrfs_set_header_nritems(right, right_nritems); |
| push_space = BTRFS_LEAF_DATA_SIZE(root); |
| 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 |
| clean_tree_block(trans, root->fs_info, 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) |
| clean_tree_block(trans, root->fs_info, 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 = read_node_slot(root, upper, slot + 1); |
| if (right == NULL) |
| return 1; |
| |
| btrfs_tree_lock(right); |
| btrfs_set_lock_blocking(right); |
| |
| free_space = btrfs_leaf_free_space(root, 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(root, 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 leaft. */ |
| btrfs_tree_unlock(left); |
| free_extent_buffer(left); |
| path->nodes[0] = right; |
| path->slots[0] = 0; |
| path->slots[1]++; |
| return 0; |
| } |
| |
| return __push_leaf_right(trans, root, path, min_data_size, empty, |
| right, free_space, left_nritems, min_slot); |
| out_unlock: |
| btrfs_tree_unlock(right); |
| free_extent_buffer(right); |
| return 1; |
| } |
| |
| /* |
| * push some data in the path leaf to the left, trying to free up at |
| * least data_size bytes. returns zero if the push worked, nonzero otherwise |
| * |
| * max_slot can put a limit on how far into the leaf we'll push items. The |
| * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the |
| * items |
| */ |
| static noinline int __push_leaf_left(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct btrfs_path *path, int data_size, |
| int empty, struct extent_buffer *left, |
| int free_space, u32 right_nritems, |
| u32 max_slot) |
| { |
| 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; |
| |
| btrfs_init_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(root, 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(root) - |
| btrfs_item_offset_nr(right, push_items - 1); |
| |
| copy_extent_buffer(left, right, btrfs_leaf_data(left) + |
| leaf_data_end(root, left) - push_space, |
| btrfs_leaf_data(right) + |
| btrfs_item_offset_nr(right, push_items - 1), |
| push_space); |
| old_left_nritems = btrfs_header_nritems(left); |
| BUG_ON(old_left_nritems <= 0); |
| |
| 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(root) - 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(root, right); |
| memmove_extent_buffer(right, btrfs_leaf_data(right) + |
| BTRFS_LEAF_DATA_SIZE(root) - push_space, |
| btrfs_leaf_data(right) + |
| leaf_data_end(root, 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)); |
| } |
| right_nritems -= push_items; |
| btrfs_set_header_nritems(right, right_nritems); |
| push_space = BTRFS_LEAF_DATA_SIZE(root); |
| 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 |
| clean_tree_block(trans, root->fs_info, right); |
| |
| btrfs_item_key(right, &disk_key, 0); |
| fixup_low_keys(root->fs_info, 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 = read_node_slot(root, path->nodes[1], slot - 1); |
| if (left == NULL) |
| return 1; |
| |
| btrfs_tree_lock(left); |
| btrfs_set_lock_blocking(left); |
| |
| free_space = btrfs_leaf_free_space(root, 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(root, left); |
| if (free_space < data_size) { |
| ret = 1; |
| goto out; |
| } |
| |
| return __push_leaf_left(trans, root, 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_root *root, |
| struct btrfs_path *path, |
| struct extent_buffer *l, |
| struct extent_buffer *right, |
| int slot, int mid, int nritems) |
| { |
| int data_copy_size; |
| int rt_data_off; |
| int i; |
| struct btrfs_disk_key disk_key; |
| struct btrfs_map_token token; |
| |
| btrfs_init_map_token(&token); |
| |
| nritems = nritems - mid; |
| btrfs_set_header_nritems(right, nritems); |
| data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, 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(right) + BTRFS_LEAF_DATA_SIZE(root) - |
| data_copy_size, btrfs_leaf_data(l) + |
| leaf_data_end(root, l), data_copy_size); |
| |
| rt_data_off = BTRFS_LEAF_DATA_SIZE(root) - |
| btrfs_item_end_nr(l, mid); |
| |
| 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, root, 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(root, 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(root, path->nodes[0]) >= data_size) |
| return 0; |
| |
| /* try to push all the items before our slot into the next leaf */ |
| slot = path->slots[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, |
| 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(root)) |
| 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(root, l); |
| |
| wret = push_leaf_right(trans, root, path, space_needed, |
| space_needed, 0, 0); |
| if (wret < 0) |
| return wret; |
| if (wret) { |
| 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(root, 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(root)) { |
| if (slot >= nritems) { |
| split = 0; |
| } else { |
| mid = slot; |
| if (mid != nritems && |
| leaf_space_used(l, mid, nritems - mid) + |
| data_size > BTRFS_LEAF_DATA_SIZE(root)) { |
| 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(root)) { |
| 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(root)) { |
| 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 = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, |
| &disk_key, 0, l->start, 0); |
| if (IS_ERR(right)) |
| return PTR_ERR(right); |
| |
| root_add_used(root, root->nodesize); |
| |
| memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header)); |
| btrfs_set_header_bytenr(right, right->start); |
| btrfs_set_header_generation(right, trans->transid); |
| btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV); |
| btrfs_set_header_owner(right, root->root_key.objectid); |
| btrfs_set_header_level(right, 0); |
| write_extent_buffer(right, fs_info->fsid, |
| btrfs_header_fsid(), BTRFS_FSID_SIZE); |
| |
| write_extent_buffer(right, fs_info->chunk_tree_uuid, |
| btrfs_header_chunk_tree_uuid(right), |
| BTRFS_UUID_SIZE); |
| |
| if (split == 0) { |
| if (mid <= slot) { |
| btrfs_set_header_nritems(right, 0); |
| insert_ptr(trans, root, 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, root, 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(fs_info, path, &disk_key, 1); |
| } |
| btrfs_mark_buffer_dirty(right); |
| return ret; |
| } |
| |
| copy_for_split(trans, root, 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(root, 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(root, 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(root, 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_trans_handle *trans, |
| struct btrfs_root *root, |
| struct btrfs_path *path, |
| 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(root, 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(root, 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, |
| struct btrfs_key *new_key, |
| unsigned long split_offset) |
| { |
| int ret; |
| ret = setup_leaf_for_split(trans, root, path, |
| sizeof(struct btrfs_item)); |
| if (ret) |
| return ret; |
| |
| ret = split_item(trans, root, 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, |
| 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_root *root, 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; |
| |
| btrfs_init_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(root, 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 */ |
| 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(leaf) + |
| data_end + size_diff, btrfs_leaf_data(leaf) + |
| 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(leaf) + |
| data_end + size_diff, btrfs_leaf_data(leaf) + |
| 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(root->fs_info, 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(root, leaf) < 0) { |
| btrfs_print_leaf(root, leaf); |
| BUG(); |
| } |
| } |
| |
| /* |
| * make the item pointed to by the path bigger, data_size is the added size. |
| */ |
| void btrfs_extend_item(struct btrfs_root *root, 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; |
| |
| btrfs_init_map_token(&token); |
| |
| leaf = path->nodes[0]; |
| |
| nritems = btrfs_header_nritems(leaf); |
| data_end = leaf_data_end(root, leaf); |
| |
| if (btrfs_leaf_free_space(root, leaf) < data_size) { |
| btrfs_print_leaf(root, leaf); |
| BUG(); |
| } |
| slot = path->slots[0]; |
| old_data = btrfs_item_end_nr(leaf, slot); |
| |
| BUG_ON(slot < 0); |
| if (slot >= nritems) { |
| btrfs_print_leaf(root, leaf); |
| btrfs_crit(root->fs_info, "slot %d too large, nritems %d", |
| slot, nritems); |
| BUG_ON(1); |
| } |
| |
| /* |
| * 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 - data_size, &token); |
| } |
| |
| /* shift the data */ |
| memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
| data_end - data_size, btrfs_leaf_data(leaf) + |
| 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(root, leaf) < 0) { |
| btrfs_print_leaf(root, 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, |
| struct btrfs_key *cpu_key, u32 *data_size, |
| u32 total_data, u32 total_size, int nr) |
| { |
| 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(root->fs_info, path, &disk_key, 1); |
| } |
| btrfs_unlock_up_safe(path, 1); |
| |
| btrfs_init_map_token(&token); |
| |
| leaf = path->nodes[0]; |
| slot = path->slots[0]; |
| |
| nritems = btrfs_header_nritems(leaf); |
| data_end = leaf_data_end(root, leaf); |
| |
| if (btrfs_leaf_free_space(root, leaf) < total_size) { |
| btrfs_print_leaf(root, leaf); |
| btrfs_crit(root->fs_info, "not enough freespace need %u have %d", |
| total_size, btrfs_leaf_free_space(root, leaf)); |
| BUG(); |
| } |
| |
| if (slot != nritems) { |
| unsigned int old_data = btrfs_item_end_nr(leaf, slot); |
| |
| if (old_data < data_end) { |
| btrfs_print_leaf(root, leaf); |
| btrfs_crit(root->fs_info, "slot %d old_data %d data_end %d", |
| slot, old_data, data_end); |
| BUG_ON(1); |
| } |
| /* |
| * 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(leaf) + |
| data_end - total_data, btrfs_leaf_data(leaf) + |
| 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(root, leaf) < 0) { |
| btrfs_print_leaf(root, 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, |
| 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, 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) |
| tree_mod_log_eb_move(root->fs_info, parent, slot, |
| slot + 1, nritems - slot - 1); |
| 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(root->fs_info, 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(root->fs_info, 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); |
| |
| extent_buffer_get(leaf); |
| 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 extent_buffer *leaf; |
| struct btrfs_item *item; |
| int last_off; |
| int dsize = 0; |
| int ret = 0; |
| int wret; |
| int i; |
| u32 nritems; |
| struct btrfs_map_token token; |
| |
| btrfs_init_map_token(&token); |
| |
| 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(root, leaf); |
| |
| memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) + |
| data_end + dsize, |
| btrfs_leaf_data(leaf) + data_end, |
| last_off - data_end); |
| |
| 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); |
| clean_tree_block(trans, root->fs_info, 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(root->fs_info, path, &disk_key, 1); |
| } |
| |
| /* delete the leaf if it is mostly empty */ |
| if (used < BTRFS_LEAF_DATA_SIZE(root) / 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]; |
| extent_buffer_get(leaf); |
| |
| 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 does lock as it descends, and path->keep_locks should be set |
| * to 1 by the caller. |
| * |
| * 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 = bin_search(cur, min_key, level, &slot); |
| |
| /* 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 = read_node_slot(root, cur, slot); |
| BUG_ON(!cur); /* -ENOMEM */ |
| |
| btrfs_tree_read_lock(cur); |
| |
| path->locks[level - 1] = BTRFS_READ_LOCK; |
| path->nodes[level - 1] = cur; |
| unlock_up(path, level, 1, 0, NULL); |
| btrfs_clear_path_blocking(path, NULL, 0); |
| } |
| 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; |
| } |
| |
| static void tree_move_down(struct btrfs_root *root, |
| struct btrfs_path *path, |
| int *level, int root_level) |
| { |
| BUG_ON(*level == 0); |
| path->nodes[*level - 1] = read_node_slot(root, path->nodes[*level], |
| path->slots[*level]); |
| path->slots[*level - 1] = 0; |
| (*level)--; |
| } |
| |
| static int tree_move_next_or_upnext(struct btrfs_root *root, |
| struct btrfs_path *path, |
| int *level, int root_level) |
| { |
| int ret = 0; |
| int nritems; |
| nritems = btrfs_header_nritems(path->nodes[*level]); |
| |
| path->slots[*level]++; |
| |
| while (path->slots[*level] >= nritems) { |
| if (*level == root_level) |
| return -1; |
| |
| /* move upnext */ |
| path->slots[*level] = 0; |
| free_extent_buffer(path->nodes[*level]); |
| path->nodes[*level] = NULL; |
| (*level)++; |
| path->slots[*level]++; |
| |
| nritems = btrfs_header_nritems(path->nodes[*level]); |
| ret = 1; |
| } |
| return ret; |
| } |
| |
| /* |
| * Returns 1 if it had to move up and next. 0 is returned if it moved only next |
| * or down. |
| */ |
| static int tree_advance(struct btrfs_root *root, |
| struct btrfs_path *path, |
| int *level, int root_level, |
| int allow_down, |
| struct btrfs_key *key) |
| { |
| int ret; |
| |
| if (*level == 0 || !allow_down) { |
| ret = tree_move_next_or_upnext(root, path, level, root_level); |
| } else { |
| tree_move_down(root, path, level, root_level); |
| ret = 0; |
| } |
| if (ret >= 0) { |
| if (*level == 0) |
| btrfs_item_key_to_cpu(path->nodes[*level], key, |
| path->slots[*level]); |
| else |
| btrfs_node_key_to_cpu(path->nodes[*level], key, |
| path->slots[*level]); |
| } |
| return ret; |
| } |
| |
| static int tree_compare_item(struct btrfs_root *left_root, |
| struct btrfs_path *left_path, |
| struct btrfs_path *right_path, |
| char *tmp_buf) |
| { |
| int cmp; |
| int len1, len2; |
| unsigned long off1, off2; |
| |
| len1 = btrfs_item_size_nr(left_path->nodes[0], left_path->slots[0]); |
| len2 = btrfs_item_size_nr(right_path->nodes[0], right_path->slots[0]); |
| if (len1 != len2) |
| return 1; |
| |
| off1 = btrfs_item_ptr_offset(left_path->nodes[0], left_path->slots[0]); |
| off2 = btrfs_item_ptr_offset(right_path->nodes[0], |
| right_path->slots[0]); |
| |
| read_extent_buffer(left_path->nodes[0], tmp_buf, off1, len1); |
| |
| cmp = memcmp_extent_buffer(right_path->nodes[0], tmp_buf, off2, len1); |
| if (cmp) |
| return 1; |
| return 0; |
| } |
| |
| #define ADVANCE 1 |
| #define ADVANCE_ONLY_NEXT -1 |
| |
| /* |
| * This function compares two trees and calls the provided callback for |
| * every changed/new/deleted item it finds. |
| * If shared tree blocks are encountered, whole subtrees are skipped, making |
| * the compare pretty fast on snapshotted subvolumes. |
| * |
| * This currently works on commit roots only. As commit roots are read only, |
| * we don't do any locking. The commit roots are protected with transactions. |
| * Transactions are ended and rejoined when a commit is tried in between. |
| * |
| * This function checks for modifications done to the trees while comparing. |
| * If it detects a change, it aborts immediately. |
| */ |
| int btrfs_compare_trees(struct btrfs_root *left_root, |
| struct btrfs_root *right_root, |
| btrfs_changed_cb_t changed_cb, void *ctx) |
| { |
| int ret; |
| int cmp; |
| struct btrfs_path *left_path = NULL; |
| struct btrfs_path *right_path = NULL; |
| struct btrfs_key left_key; |
| struct btrfs_key right_key; |
| char *tmp_buf = NULL; |
| int left_root_level; |
| int right_root_level; |
| int left_level; |
| int right_level; |
| int left_end_reached; |
| int right_end_reached; |
| int advance_left; |
| int advance_right; |
| u64 left_blockptr; |
| u64 right_blockptr; |
| u64 left_gen; |
| u64 right_gen; |
| |
| left_path = btrfs_alloc_path(); |
| if (!left_path) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| right_path = btrfs_alloc_path(); |
| if (!right_path) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| tmp_buf = kmalloc(left_root->nodesize, GFP_NOFS); |
| if (!tmp_buf) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| left_path->search_commit_root = 1; |
| left_path->skip_locking = 1; |
| right_path->search_commit_root = 1; |
| right_path->skip_locking = 1; |
| |
| /* |
| * Strategy: Go to the first items of both trees. Then do |
| * |
| * If both trees are at level 0 |
| * Compare keys of current items |
| * If left < right treat left item as new, advance left tree |
| * and repeat |
| * If left > right treat right item as deleted, advance right tree |
| * and repeat |
| * If left == right do deep compare of items, treat as changed if |
| * needed, advance both trees and repeat |
| * If both trees are at the same level but not at level 0 |
| * Compare keys of current nodes/leafs |
| * If left < right advance left tree and repeat |
| * If left > right advance right tree and repeat |
| * If left == right compare blockptrs of the next nodes/leafs |
| * If they match advance both trees but stay at the same level |
| * and repeat |
| * If they don't match advance both trees while allowing to go |
| * deeper and repeat |
| * If tree levels are different |
| * Advance the tree that needs it and repeat |
| * |
| * Advancing a tree means: |
| * If we are at level 0, try to go to the next slot. If that's not |
| * possible, go one level up and repeat. Stop when we found a level |
| * where we could go to the next slot. We may at this point be on a |
| * node or a leaf. |
| * |
| * If we are not at level 0 and not on shared tree blocks, go one |
| * level deeper. |
| * |
| * If we are not at level 0 and on shared tree blocks, go one slot to |
| * the right if possible or go up and right. |
| */ |
| |
| down_read(&left_root->fs_info->commit_root_sem); |
| left_level = btrfs_header_level(left_root->commit_root); |
| left_root_level = left_level; |
| left_path->nodes[left_level] = left_root->commit_root; |
| extent_buffer_get(left_path->nodes[left_level]); |
| |
| right_level = btrfs_header_level(right_root->commit_root); |
| right_root_level = right_level; |
| right_path->nodes[right_level] = right_root->commit_root; |
| extent_buffer_get(right_path->nodes[right_level]); |
| up_read(&left_root->fs_info->commit_root_sem); |
| |
| if (left_level == 0) |
| btrfs_item_key_to_cpu(left_path->nodes[left_level], |
| &left_key, left_path->slots[left_level]); |
| else |
| btrfs_node_key_to_cpu(left_path->nodes[left_level], |
| &left_key, left_path->slots[left_level]); |
| if (right_level == 0) |
| btrfs_item_key_to_cpu(right_path->nodes[right_level], |
| &right_key, right_path->slots[right_level]); |
| else |
| btrfs_node_key_to_cpu(right_path->nodes[right_level], |
| &right_key, right_path->slots[right_level]); |
| |
| left_end_reached = right_end_reached = 0; |
| advance_left = advance_right = 0; |
| |
| while (1) { |
| if (advance_left && !left_end_reached) { |
| ret = tree_advance(left_root, left_path, &left_level, |
| left_root_level, |
| advance_left != ADVANCE_ONLY_NEXT, |
| &left_key); |
| if (ret < 0) |
| left_end_reached = ADVANCE; |
| advance_left = 0; |
| } |
| if (advance_right && !right_end_reached) { |
| ret = tree_advance(right_root, right_path, &right_level, |
| right_root_level, |
| advance_right != ADVANCE_ONLY_NEXT, |
| &right_key); |
| if (ret < 0) |
| right_end_reached = ADVANCE; |
| advance_right = 0; |
| } |
| |
| if (left_end_reached && right_end_reached) { |
| ret = 0; |
| goto out; |
| } else if (left_end_reached) { |
| if (right_level == 0) { |
| ret = changed_cb(left_root, right_root, |
| left_path, right_path, |
| &right_key, |
| BTRFS_COMPARE_TREE_DELETED, |
| ctx); |
| if (ret < 0) |
| goto out; |
| } |
| advance_right = ADVANCE; |
| continue; |
| } else if (right_end_reached) { |
| if (left_level == 0) { |
| ret = changed_cb(left_root, right_root, |
| left_path, right_path, |
| &left_key, |
| BTRFS_COMPARE_TREE_NEW, |
| ctx); |
| if (ret < 0) |
| goto out; |
| } |
| advance_left = ADVANCE; |
| continue; |
| } |
| |
| if (left_level == 0 && right_level == 0) { |
| cmp = btrfs_comp_cpu_keys(&left_key, &right_key); |
| if (cmp < 0) { |
| ret = changed_cb(left_root, right_root, |
| left_path, right_path, |
| &left_key, |
| BTRFS_COMPARE_TREE_NEW, |
| ctx); |
| if (ret < 0) |
| goto out; |
| advance_left = ADVANCE; |
| } else if (cmp > 0) { |
| ret = changed_cb(left_root, right_root, |
| left_path, right_path, |
| &right_key, |
| BTRFS_COMPARE_TREE_DELETED, |
| ctx); |
| if (ret < 0) |
| goto out; |
| advance_right = ADVANCE; |
| } else { |
| enum btrfs_compare_tree_result result; |
| |
| WARN_ON(!extent_buffer_uptodate(left_path->nodes[0])); |
| ret = tree_compare_item(left_root, left_path, |
| right_path, tmp_buf); |
| if (ret) |
| result = BTRFS_COMPARE_TREE_CHANGED; |
| else |
| result = BTRFS_COMPARE_TREE_SAME; |
| ret = changed_cb(left_root, right_root, |
| left_path, right_path, |
| &left_key, result, ctx); |
| if (ret < 0) |
| goto out; |
| advance_left = ADVANCE; |
| advance_right = ADVANCE; |
| } |
| } else if (left_level == right_level) { |
| cmp = btrfs_comp_cpu_keys(&left_key, &right_key); |
| if (cmp < 0) { |
| advance_left = ADVANCE; |
| } else if (cmp > 0) { |
| advance_right = ADVANCE; |
| } else { |
| left_blockptr = btrfs_node_blockptr( |
| left_path->nodes[left_level], |
| left_path->slots[left_level]); |
| right_blockptr = btrfs_node_blockptr( |
| right_path->nodes[right_level], |
| right_path->slots[right_level]); |
| left_gen = btrfs_node_ptr_generation( |
| left_path->nodes[left_level], |
| left_path->slots[left_level]); |
| right_gen = btrfs_node_ptr_generation( |
| right_path->nodes[right_level], |
| right_path->slots[right_level]); |
| if (left_blockptr == right_blockptr && |
| left_gen == right_gen) { |
| /* |
| * As we're on a shared block, don't |
| * allow to go deeper. |
| */ |
| advance_left = ADVANCE_ONLY_NEXT; |
| advance_right = ADVANCE_ONLY_NEXT; |
| } else { |
| advance_left = ADVANCE; |
| advance_right = ADVANCE; |
| } |
| } |
| } else if (left_level < right_level) { |
| advance_right = ADVANCE; |
| } else { |
| advance_left = ADVANCE; |
| } |
| } |
| |
| out: |
| btrfs_free_path(left_path); |
| btrfs_free_path(right_path); |
| kfree(tmp_buf); |
| 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); |
| 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]) { |
| 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(NULL, root, path, &next, level, |
| slot, &key, 0); |
| 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); |
| btrfs_clear_path_blocking(path, next, |
| BTRFS_READ_LOCK); |
| } |
| 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(NULL, root, path, &next, level, |
| 0, &key, 0); |
| 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); |
| btrfs_clear_path_blocking(path, next, |
| BTRFS_READ_LOCK); |
| } |
| 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; |
| } |