| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 2007,2008 Oracle. All rights reserved. |
| */ |
| |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/rbtree.h> |
| #include <linux/mm.h> |
| #include <linux/error-injection.h> |
| #include "messages.h" |
| #include "ctree.h" |
| #include "disk-io.h" |
| #include "transaction.h" |
| #include "print-tree.h" |
| #include "locking.h" |
| #include "volumes.h" |
| #include "qgroup.h" |
| #include "tree-mod-log.h" |
| #include "tree-checker.h" |
| #include "fs.h" |
| #include "accessors.h" |
| #include "extent-tree.h" |
| #include "relocation.h" |
| #include "file-item.h" |
| |
| static struct kmem_cache *btrfs_path_cachep; |
| |
| static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root |
| *root, struct btrfs_path *path, int level); |
| static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| const struct btrfs_key *ins_key, struct btrfs_path *path, |
| int data_size, int extend); |
| static int push_node_left(struct btrfs_trans_handle *trans, |
| struct extent_buffer *dst, |
| struct extent_buffer *src, int empty); |
| static int balance_node_right(struct btrfs_trans_handle *trans, |
| struct extent_buffer *dst_buf, |
| struct extent_buffer *src_buf); |
| |
| static const struct btrfs_csums { |
| u16 size; |
| const char name[10]; |
| const char driver[12]; |
| } btrfs_csums[] = { |
| [BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" }, |
| [BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" }, |
| [BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" }, |
| [BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b", |
| .driver = "blake2b-256" }, |
| }; |
| |
| /* |
| * The leaf data grows from end-to-front in the node. this returns the address |
| * of the start of the last item, which is the stop of the leaf data stack. |
| */ |
| static unsigned int leaf_data_end(const struct extent_buffer *leaf) |
| { |
| u32 nr = btrfs_header_nritems(leaf); |
| |
| if (nr == 0) |
| return BTRFS_LEAF_DATA_SIZE(leaf->fs_info); |
| return btrfs_item_offset(leaf, nr - 1); |
| } |
| |
| /* |
| * Move data in a @leaf (using memmove, safe for overlapping ranges). |
| * |
| * @leaf: leaf that we're doing a memmove on |
| * @dst_offset: item data offset we're moving to |
| * @src_offset: item data offset were' moving from |
| * @len: length of the data we're moving |
| * |
| * Wrapper around memmove_extent_buffer() that takes into account the header on |
| * the leaf. The btrfs_item offset's start directly after the header, so we |
| * have to adjust any offsets to account for the header in the leaf. This |
| * handles that math to simplify the callers. |
| */ |
| static inline void memmove_leaf_data(const struct extent_buffer *leaf, |
| unsigned long dst_offset, |
| unsigned long src_offset, |
| unsigned long len) |
| { |
| memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) + dst_offset, |
| btrfs_item_nr_offset(leaf, 0) + src_offset, len); |
| } |
| |
| /* |
| * Copy item data from @src into @dst at the given @offset. |
| * |
| * @dst: destination leaf that we're copying into |
| * @src: source leaf that we're copying from |
| * @dst_offset: item data offset we're copying to |
| * @src_offset: item data offset were' copying from |
| * @len: length of the data we're copying |
| * |
| * Wrapper around copy_extent_buffer() that takes into account the header on |
| * the leaf. The btrfs_item offset's start directly after the header, so we |
| * have to adjust any offsets to account for the header in the leaf. This |
| * handles that math to simplify the callers. |
| */ |
| static inline void copy_leaf_data(const struct extent_buffer *dst, |
| const struct extent_buffer *src, |
| unsigned long dst_offset, |
| unsigned long src_offset, unsigned long len) |
| { |
| copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, 0) + dst_offset, |
| btrfs_item_nr_offset(src, 0) + src_offset, len); |
| } |
| |
| /* |
| * Move items in a @leaf (using memmove). |
| * |
| * @dst: destination leaf for the items |
| * @dst_item: the item nr we're copying into |
| * @src_item: the item nr we're copying from |
| * @nr_items: the number of items to copy |
| * |
| * Wrapper around memmove_extent_buffer() that does the math to get the |
| * appropriate offsets into the leaf from the item numbers. |
| */ |
| static inline void memmove_leaf_items(const struct extent_buffer *leaf, |
| int dst_item, int src_item, int nr_items) |
| { |
| memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, dst_item), |
| btrfs_item_nr_offset(leaf, src_item), |
| nr_items * sizeof(struct btrfs_item)); |
| } |
| |
| /* |
| * Copy items from @src into @dst at the given @offset. |
| * |
| * @dst: destination leaf for the items |
| * @src: source leaf for the items |
| * @dst_item: the item nr we're copying into |
| * @src_item: the item nr we're copying from |
| * @nr_items: the number of items to copy |
| * |
| * Wrapper around copy_extent_buffer() that does the math to get the |
| * appropriate offsets into the leaf from the item numbers. |
| */ |
| static inline void copy_leaf_items(const struct extent_buffer *dst, |
| const struct extent_buffer *src, |
| int dst_item, int src_item, int nr_items) |
| { |
| copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, dst_item), |
| btrfs_item_nr_offset(src, src_item), |
| nr_items * sizeof(struct btrfs_item)); |
| } |
| |
| /* This exists for btrfs-progs usages. */ |
| u16 btrfs_csum_type_size(u16 type) |
| { |
| return btrfs_csums[type].size; |
| } |
| |
| int btrfs_super_csum_size(const struct btrfs_super_block *s) |
| { |
| u16 t = btrfs_super_csum_type(s); |
| /* |
| * csum type is validated at mount time |
| */ |
| return btrfs_csum_type_size(t); |
| } |
| |
| const char *btrfs_super_csum_name(u16 csum_type) |
| { |
| /* csum type is validated at mount time */ |
| return btrfs_csums[csum_type].name; |
| } |
| |
| /* |
| * Return driver name if defined, otherwise the name that's also a valid driver |
| * name |
| */ |
| const char *btrfs_super_csum_driver(u16 csum_type) |
| { |
| /* csum type is validated at mount time */ |
| return btrfs_csums[csum_type].driver[0] ? |
| btrfs_csums[csum_type].driver : |
| btrfs_csums[csum_type].name; |
| } |
| |
| size_t __attribute_const__ btrfs_get_num_csums(void) |
| { |
| return ARRAY_SIZE(btrfs_csums); |
| } |
| |
| struct btrfs_path *btrfs_alloc_path(void) |
| { |
| might_sleep(); |
| |
| return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS); |
| } |
| |
| /* this also releases the path */ |
| void btrfs_free_path(struct btrfs_path *p) |
| { |
| if (!p) |
| return; |
| btrfs_release_path(p); |
| kmem_cache_free(btrfs_path_cachep, p); |
| } |
| |
| /* |
| * path release drops references on the extent buffers in the path |
| * and it drops any locks held by this path |
| * |
| * It is safe to call this on paths that no locks or extent buffers held. |
| */ |
| noinline void btrfs_release_path(struct btrfs_path *p) |
| { |
| int i; |
| |
| for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
| p->slots[i] = 0; |
| if (!p->nodes[i]) |
| continue; |
| if (p->locks[i]) { |
| btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]); |
| p->locks[i] = 0; |
| } |
| free_extent_buffer(p->nodes[i]); |
| p->nodes[i] = NULL; |
| } |
| } |
| |
| /* |
| * We want the transaction abort to print stack trace only for errors where the |
| * cause could be a bug, eg. due to ENOSPC, and not for common errors that are |
| * caused by external factors. |
| */ |
| bool __cold abort_should_print_stack(int error) |
| { |
| switch (error) { |
| case -EIO: |
| case -EROFS: |
| case -ENOMEM: |
| return false; |
| } |
| return true; |
| } |
| |
| /* |
| * safely gets a reference on the root node of a tree. A lock |
| * is not taken, so a concurrent writer may put a different node |
| * at the root of the tree. See btrfs_lock_root_node for the |
| * looping required. |
| * |
| * The extent buffer returned by this has a reference taken, so |
| * it won't disappear. It may stop being the root of the tree |
| * at any time because there are no locks held. |
| */ |
| struct extent_buffer *btrfs_root_node(struct btrfs_root *root) |
| { |
| struct extent_buffer *eb; |
| |
| while (1) { |
| rcu_read_lock(); |
| eb = rcu_dereference(root->node); |
| |
| /* |
| * RCU really hurts here, we could free up the root node because |
| * it was COWed but we may not get the new root node yet so do |
| * the inc_not_zero dance and if it doesn't work then |
| * synchronize_rcu and try again. |
| */ |
| if (atomic_inc_not_zero(&eb->refs)) { |
| rcu_read_unlock(); |
| break; |
| } |
| rcu_read_unlock(); |
| synchronize_rcu(); |
| } |
| return eb; |
| } |
| |
| /* |
| * Cowonly root (not-shareable trees, everything not subvolume or reloc roots), |
| * just get put onto a simple dirty list. Transaction walks this list to make |
| * sure they get properly updated on disk. |
| */ |
| static void add_root_to_dirty_list(struct btrfs_root *root) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| |
| if (test_bit(BTRFS_ROOT_DIRTY, &root->state) || |
| !test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state)) |
| return; |
| |
| spin_lock(&fs_info->trans_lock); |
| if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) { |
| /* Want the extent tree to be the last on the list */ |
| if (btrfs_root_id(root) == BTRFS_EXTENT_TREE_OBJECTID) |
| list_move_tail(&root->dirty_list, |
| &fs_info->dirty_cowonly_roots); |
| else |
| list_move(&root->dirty_list, |
| &fs_info->dirty_cowonly_roots); |
| } |
| spin_unlock(&fs_info->trans_lock); |
| } |
| |
| /* |
| * used by snapshot creation to make a copy of a root for a tree with |
| * a given objectid. The buffer with the new root node is returned in |
| * cow_ret, and this func returns zero on success or a negative error code. |
| */ |
| int btrfs_copy_root(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct extent_buffer *buf, |
| struct extent_buffer **cow_ret, u64 new_root_objectid) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct extent_buffer *cow; |
| int ret = 0; |
| int level; |
| struct btrfs_disk_key disk_key; |
| u64 reloc_src_root = 0; |
| |
| WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
| trans->transid != fs_info->running_transaction->transid); |
| WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
| trans->transid != btrfs_get_root_last_trans(root)); |
| |
| level = btrfs_header_level(buf); |
| if (level == 0) |
| btrfs_item_key(buf, &disk_key, 0); |
| else |
| btrfs_node_key(buf, &disk_key, 0); |
| |
| if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
| reloc_src_root = btrfs_header_owner(buf); |
| cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid, |
| &disk_key, level, buf->start, 0, |
| reloc_src_root, BTRFS_NESTING_NEW_ROOT); |
| if (IS_ERR(cow)) |
| return PTR_ERR(cow); |
| |
| copy_extent_buffer_full(cow, buf); |
| btrfs_set_header_bytenr(cow, cow->start); |
| btrfs_set_header_generation(cow, trans->transid); |
| btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
| btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
| BTRFS_HEADER_FLAG_RELOC); |
| if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
| btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
| else |
| btrfs_set_header_owner(cow, new_root_objectid); |
| |
| write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid); |
| |
| WARN_ON(btrfs_header_generation(buf) > trans->transid); |
| if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
| ret = btrfs_inc_ref(trans, root, cow, 1); |
| else |
| ret = btrfs_inc_ref(trans, root, cow, 0); |
| if (ret) { |
| btrfs_tree_unlock(cow); |
| free_extent_buffer(cow); |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| |
| btrfs_mark_buffer_dirty(trans, cow); |
| *cow_ret = cow; |
| return 0; |
| } |
| |
| /* |
| * check if the tree block can be shared by multiple trees |
| */ |
| bool btrfs_block_can_be_shared(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct extent_buffer *buf) |
| { |
| const u64 buf_gen = btrfs_header_generation(buf); |
| |
| /* |
| * Tree blocks not in shareable trees and tree roots are never shared. |
| * If a block was allocated after the last snapshot and the block was |
| * not allocated by tree relocation, we know the block is not shared. |
| */ |
| |
| if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) |
| return false; |
| |
| if (buf == root->node) |
| return false; |
| |
| if (buf_gen > btrfs_root_last_snapshot(&root->root_item) && |
| !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) |
| return false; |
| |
| if (buf != root->commit_root) |
| return true; |
| |
| /* |
| * An extent buffer that used to be the commit root may still be shared |
| * because the tree height may have increased and it became a child of a |
| * higher level root. This can happen when snapshotting a subvolume |
| * created in the current transaction. |
| */ |
| if (buf_gen == trans->transid) |
| return true; |
| |
| return false; |
| } |
| |
| static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct extent_buffer *buf, |
| struct extent_buffer *cow, |
| int *last_ref) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| u64 refs; |
| u64 owner; |
| u64 flags; |
| int ret; |
| |
| /* |
| * Backrefs update rules: |
| * |
| * Always use full backrefs for extent pointers in tree block |
| * allocated by tree relocation. |
| * |
| * If a shared tree block is no longer referenced by its owner |
| * tree (btrfs_header_owner(buf) == root->root_key.objectid), |
| * use full backrefs for extent pointers in tree block. |
| * |
| * If a tree block is been relocating |
| * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID), |
| * use full backrefs for extent pointers in tree block. |
| * The reason for this is some operations (such as drop tree) |
| * are only allowed for blocks use full backrefs. |
| */ |
| |
| if (btrfs_block_can_be_shared(trans, root, buf)) { |
| ret = btrfs_lookup_extent_info(trans, fs_info, buf->start, |
| btrfs_header_level(buf), 1, |
| &refs, &flags, NULL); |
| if (ret) |
| return ret; |
| if (unlikely(refs == 0)) { |
| btrfs_crit(fs_info, |
| "found 0 references for tree block at bytenr %llu level %d root %llu", |
| buf->start, btrfs_header_level(buf), |
| btrfs_root_id(root)); |
| ret = -EUCLEAN; |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| } else { |
| refs = 1; |
| if (btrfs_root_id(root) == 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); |
| if (unlikely(owner == BTRFS_TREE_RELOC_OBJECTID && |
| !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))) { |
| btrfs_crit(fs_info, |
| "found tree block at bytenr %llu level %d root %llu refs %llu flags %llx without full backref flag set", |
| buf->start, btrfs_header_level(buf), |
| btrfs_root_id(root), refs, flags); |
| ret = -EUCLEAN; |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| |
| if (refs > 1) { |
| if ((owner == btrfs_root_id(root) || |
| btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID) && |
| !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) { |
| ret = btrfs_inc_ref(trans, root, buf, 1); |
| if (ret) |
| return ret; |
| |
| if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID) { |
| ret = btrfs_dec_ref(trans, root, buf, 0); |
| if (ret) |
| return ret; |
| ret = btrfs_inc_ref(trans, root, cow, 1); |
| if (ret) |
| return ret; |
| } |
| ret = btrfs_set_disk_extent_flags(trans, buf, |
| BTRFS_BLOCK_FLAG_FULL_BACKREF); |
| if (ret) |
| return ret; |
| } else { |
| |
| if (btrfs_root_id(root) == 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; |
| } |
| } else { |
| if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) { |
| if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID) |
| ret = btrfs_inc_ref(trans, root, cow, 1); |
| else |
| ret = btrfs_inc_ref(trans, root, cow, 0); |
| if (ret) |
| return ret; |
| ret = btrfs_dec_ref(trans, root, buf, 1); |
| if (ret) |
| return ret; |
| } |
| btrfs_clear_buffer_dirty(trans, buf); |
| *last_ref = 1; |
| } |
| return 0; |
| } |
| |
| /* |
| * does the dirty work in cow of a single block. The parent block (if |
| * supplied) is updated to point to the new cow copy. The new buffer is marked |
| * dirty and returned locked. If you modify the block it needs to be marked |
| * dirty again. |
| * |
| * search_start -- an allocation hint for the new block |
| * |
| * empty_size -- a hint that you plan on doing more cow. This is the size in |
| * bytes the allocator should try to find free next to the block it returns. |
| * This is just a hint and may be ignored by the allocator. |
| */ |
| int btrfs_force_cow_block(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct extent_buffer *buf, |
| struct extent_buffer *parent, int parent_slot, |
| struct extent_buffer **cow_ret, |
| u64 search_start, u64 empty_size, |
| enum btrfs_lock_nesting nest) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct btrfs_disk_key disk_key; |
| struct extent_buffer *cow; |
| int level, ret; |
| int last_ref = 0; |
| int unlock_orig = 0; |
| u64 parent_start = 0; |
| u64 reloc_src_root = 0; |
| |
| if (*cow_ret == buf) |
| unlock_orig = 1; |
| |
| btrfs_assert_tree_write_locked(buf); |
| |
| WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
| trans->transid != fs_info->running_transaction->transid); |
| WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
| trans->transid != btrfs_get_root_last_trans(root)); |
| |
| level = btrfs_header_level(buf); |
| |
| if (level == 0) |
| btrfs_item_key(buf, &disk_key, 0); |
| else |
| btrfs_node_key(buf, &disk_key, 0); |
| |
| if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID) { |
| if (parent) |
| parent_start = parent->start; |
| reloc_src_root = btrfs_header_owner(buf); |
| } |
| cow = btrfs_alloc_tree_block(trans, root, parent_start, |
| btrfs_root_id(root), &disk_key, level, |
| search_start, empty_size, reloc_src_root, nest); |
| if (IS_ERR(cow)) |
| return PTR_ERR(cow); |
| |
| /* cow is set to blocking by btrfs_init_new_buffer */ |
| |
| copy_extent_buffer_full(cow, buf); |
| btrfs_set_header_bytenr(cow, cow->start); |
| btrfs_set_header_generation(cow, trans->transid); |
| btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
| btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
| BTRFS_HEADER_FLAG_RELOC); |
| if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID) |
| btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
| else |
| btrfs_set_header_owner(cow, btrfs_root_id(root)); |
| |
| write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid); |
| |
| ret = update_ref_for_cow(trans, root, buf, cow, &last_ref); |
| if (ret) { |
| btrfs_abort_transaction(trans, ret); |
| goto error_unlock_cow; |
| } |
| |
| if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { |
| ret = btrfs_reloc_cow_block(trans, root, buf, cow); |
| if (ret) { |
| btrfs_abort_transaction(trans, ret); |
| goto error_unlock_cow; |
| } |
| } |
| |
| if (buf == root->node) { |
| WARN_ON(parent && parent != buf); |
| if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID || |
| btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
| parent_start = buf->start; |
| |
| ret = btrfs_tree_mod_log_insert_root(root->node, cow, true); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto error_unlock_cow; |
| } |
| atomic_inc(&cow->refs); |
| rcu_assign_pointer(root->node, cow); |
| |
| ret = btrfs_free_tree_block(trans, btrfs_root_id(root), buf, |
| parent_start, last_ref); |
| free_extent_buffer(buf); |
| add_root_to_dirty_list(root); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto error_unlock_cow; |
| } |
| } else { |
| WARN_ON(trans->transid != btrfs_header_generation(parent)); |
| ret = btrfs_tree_mod_log_insert_key(parent, parent_slot, |
| BTRFS_MOD_LOG_KEY_REPLACE); |
| if (ret) { |
| btrfs_abort_transaction(trans, ret); |
| goto error_unlock_cow; |
| } |
| btrfs_set_node_blockptr(parent, parent_slot, |
| cow->start); |
| btrfs_set_node_ptr_generation(parent, parent_slot, |
| trans->transid); |
| btrfs_mark_buffer_dirty(trans, parent); |
| if (last_ref) { |
| ret = btrfs_tree_mod_log_free_eb(buf); |
| if (ret) { |
| btrfs_abort_transaction(trans, ret); |
| goto error_unlock_cow; |
| } |
| } |
| ret = btrfs_free_tree_block(trans, btrfs_root_id(root), buf, |
| parent_start, last_ref); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto error_unlock_cow; |
| } |
| } |
| if (unlock_orig) |
| btrfs_tree_unlock(buf); |
| free_extent_buffer_stale(buf); |
| btrfs_mark_buffer_dirty(trans, cow); |
| *cow_ret = cow; |
| return 0; |
| |
| error_unlock_cow: |
| btrfs_tree_unlock(cow); |
| free_extent_buffer(cow); |
| return ret; |
| } |
| |
| static inline int should_cow_block(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct extent_buffer *buf) |
| { |
| if (btrfs_is_testing(root->fs_info)) |
| return 0; |
| |
| /* Ensure we can see the FORCE_COW bit */ |
| smp_mb__before_atomic(); |
| |
| /* |
| * We do not need to cow a block if |
| * 1) this block is not created or changed in this transaction; |
| * 2) this block does not belong to TREE_RELOC tree; |
| * 3) the root is not forced COW. |
| * |
| * What is forced COW: |
| * when we create snapshot during committing the transaction, |
| * after we've finished copying src root, we must COW the shared |
| * block to ensure the metadata consistency. |
| */ |
| if (btrfs_header_generation(buf) == trans->transid && |
| !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) && |
| !(btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID && |
| btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) && |
| !test_bit(BTRFS_ROOT_FORCE_COW, &root->state)) |
| return 0; |
| return 1; |
| } |
| |
| /* |
| * COWs a single block, see btrfs_force_cow_block() for the real work. |
| * This version of it has extra checks so that a block isn't COWed more than |
| * once per transaction, as long as it hasn't been written yet |
| */ |
| int btrfs_cow_block(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, struct extent_buffer *buf, |
| struct extent_buffer *parent, int parent_slot, |
| struct extent_buffer **cow_ret, |
| enum btrfs_lock_nesting nest) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| u64 search_start; |
| int ret; |
| |
| if (unlikely(test_bit(BTRFS_ROOT_DELETING, &root->state))) { |
| btrfs_abort_transaction(trans, -EUCLEAN); |
| btrfs_crit(fs_info, |
| "attempt to COW block %llu on root %llu that is being deleted", |
| buf->start, btrfs_root_id(root)); |
| return -EUCLEAN; |
| } |
| |
| /* |
| * COWing must happen through a running transaction, which always |
| * matches the current fs generation (it's a transaction with a state |
| * less than TRANS_STATE_UNBLOCKED). If it doesn't, then turn the fs |
| * into error state to prevent the commit of any transaction. |
| */ |
| if (unlikely(trans->transaction != fs_info->running_transaction || |
| trans->transid != fs_info->generation)) { |
| btrfs_abort_transaction(trans, -EUCLEAN); |
| btrfs_crit(fs_info, |
| "unexpected transaction when attempting to COW block %llu on root %llu, transaction %llu running transaction %llu fs generation %llu", |
| buf->start, btrfs_root_id(root), trans->transid, |
| fs_info->running_transaction->transid, |
| fs_info->generation); |
| return -EUCLEAN; |
| } |
| |
| if (!should_cow_block(trans, root, buf)) { |
| *cow_ret = buf; |
| return 0; |
| } |
| |
| search_start = round_down(buf->start, SZ_1G); |
| |
| /* |
| * Before CoWing this block for later modification, check if it's |
| * the subtree root and do the delayed subtree trace if needed. |
| * |
| * Also We don't care about the error, as it's handled internally. |
| */ |
| btrfs_qgroup_trace_subtree_after_cow(trans, root, buf); |
| ret = btrfs_force_cow_block(trans, root, buf, parent, parent_slot, |
| cow_ret, search_start, 0, nest); |
| |
| trace_btrfs_cow_block(root, buf, *cow_ret); |
| |
| return ret; |
| } |
| ALLOW_ERROR_INJECTION(btrfs_cow_block, ERRNO); |
| |
| /* |
| * same as comp_keys only with two btrfs_key's |
| */ |
| int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2) |
| { |
| if (k1->objectid > k2->objectid) |
| return 1; |
| if (k1->objectid < k2->objectid) |
| return -1; |
| if (k1->type > k2->type) |
| return 1; |
| if (k1->type < k2->type) |
| return -1; |
| if (k1->offset > k2->offset) |
| return 1; |
| if (k1->offset < k2->offset) |
| return -1; |
| return 0; |
| } |
| |
| /* |
| * Search for a key in the given extent_buffer. |
| * |
| * The lower boundary for the search is specified by the slot number @first_slot. |
| * Use a value of 0 to search over the whole extent buffer. Works for both |
| * leaves and nodes. |
| * |
| * The slot in the extent buffer is returned via @slot. If the key exists in the |
| * extent buffer, then @slot will point to the slot where the key is, otherwise |
| * it points to the slot where you would insert the key. |
| * |
| * Slot may point to the total number of items (i.e. one position beyond the last |
| * key) if the key is bigger than the last key in the extent buffer. |
| */ |
| int btrfs_bin_search(struct extent_buffer *eb, int first_slot, |
| const struct btrfs_key *key, int *slot) |
| { |
| unsigned long p; |
| int item_size; |
| /* |
| * Use unsigned types for the low and high slots, so that we get a more |
| * efficient division in the search loop below. |
| */ |
| u32 low = first_slot; |
| u32 high = btrfs_header_nritems(eb); |
| int ret; |
| const int key_size = sizeof(struct btrfs_disk_key); |
| |
| if (unlikely(low > high)) { |
| btrfs_err(eb->fs_info, |
| "%s: low (%u) > high (%u) eb %llu owner %llu level %d", |
| __func__, low, high, eb->start, |
| btrfs_header_owner(eb), btrfs_header_level(eb)); |
| return -EINVAL; |
| } |
| |
| if (btrfs_header_level(eb) == 0) { |
| p = offsetof(struct btrfs_leaf, items); |
| item_size = sizeof(struct btrfs_item); |
| } else { |
| p = offsetof(struct btrfs_node, ptrs); |
| item_size = sizeof(struct btrfs_key_ptr); |
| } |
| |
| while (low < high) { |
| const int unit_size = eb->folio_size; |
| unsigned long oil; |
| unsigned long offset; |
| struct btrfs_disk_key *tmp; |
| struct btrfs_disk_key unaligned; |
| int mid; |
| |
| mid = (low + high) / 2; |
| offset = p + mid * item_size; |
| oil = get_eb_offset_in_folio(eb, offset); |
| |
| if (oil + key_size <= unit_size) { |
| const unsigned long idx = get_eb_folio_index(eb, offset); |
| char *kaddr = folio_address(eb->folios[idx]); |
| |
| oil = get_eb_offset_in_folio(eb, offset); |
| tmp = (struct btrfs_disk_key *)(kaddr + oil); |
| } else { |
| read_extent_buffer(eb, &unaligned, offset, key_size); |
| tmp = &unaligned; |
| } |
| |
| ret = btrfs_comp_keys(tmp, key); |
| |
| if (ret < 0) |
| low = mid + 1; |
| else if (ret > 0) |
| high = mid; |
| else { |
| *slot = mid; |
| return 0; |
| } |
| } |
| *slot = low; |
| return 1; |
| } |
| |
| static void root_add_used_bytes(struct btrfs_root *root) |
| { |
| spin_lock(&root->accounting_lock); |
| btrfs_set_root_used(&root->root_item, |
| btrfs_root_used(&root->root_item) + root->fs_info->nodesize); |
| spin_unlock(&root->accounting_lock); |
| } |
| |
| static void root_sub_used_bytes(struct btrfs_root *root) |
| { |
| spin_lock(&root->accounting_lock); |
| btrfs_set_root_used(&root->root_item, |
| btrfs_root_used(&root->root_item) - root->fs_info->nodesize); |
| spin_unlock(&root->accounting_lock); |
| } |
| |
| /* given a node and slot number, this reads the blocks it points to. The |
| * extent buffer is returned with a reference taken (but unlocked). |
| */ |
| struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent, |
| int slot) |
| { |
| int level = btrfs_header_level(parent); |
| struct btrfs_tree_parent_check check = { 0 }; |
| struct extent_buffer *eb; |
| |
| if (slot < 0 || slot >= btrfs_header_nritems(parent)) |
| return ERR_PTR(-ENOENT); |
| |
| ASSERT(level); |
| |
| check.level = level - 1; |
| check.transid = btrfs_node_ptr_generation(parent, slot); |
| check.owner_root = btrfs_header_owner(parent); |
| check.has_first_key = true; |
| btrfs_node_key_to_cpu(parent, &check.first_key, slot); |
| |
| eb = read_tree_block(parent->fs_info, btrfs_node_blockptr(parent, slot), |
| &check); |
| if (IS_ERR(eb)) |
| return eb; |
| if (!extent_buffer_uptodate(eb)) { |
| free_extent_buffer(eb); |
| return ERR_PTR(-EIO); |
| } |
| |
| return eb; |
| } |
| |
| /* |
| * node level balancing, used to make sure nodes are in proper order for |
| * item deletion. We balance from the top down, so we have to make sure |
| * that a deletion won't leave an node completely empty later on. |
| */ |
| static noinline int balance_level(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct btrfs_path *path, int level) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct extent_buffer *right = NULL; |
| struct extent_buffer *mid; |
| struct extent_buffer *left = NULL; |
| struct extent_buffer *parent = NULL; |
| int ret = 0; |
| int wret; |
| int pslot; |
| int orig_slot = path->slots[level]; |
| u64 orig_ptr; |
| |
| ASSERT(level > 0); |
| |
| mid = path->nodes[level]; |
| |
| WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK); |
| WARN_ON(btrfs_header_generation(mid) != trans->transid); |
| |
| orig_ptr = btrfs_node_blockptr(mid, orig_slot); |
| |
| if (level < BTRFS_MAX_LEVEL - 1) { |
| parent = path->nodes[level + 1]; |
| pslot = path->slots[level + 1]; |
| } |
| |
| /* |
| * deal with the case where there is only one pointer in the root |
| * by promoting the node below to a root |
| */ |
| if (!parent) { |
| struct extent_buffer *child; |
| |
| if (btrfs_header_nritems(mid) != 1) |
| return 0; |
| |
| /* promote the child to a root */ |
| child = btrfs_read_node_slot(mid, 0); |
| if (IS_ERR(child)) { |
| ret = PTR_ERR(child); |
| goto out; |
| } |
| |
| btrfs_tree_lock(child); |
| ret = btrfs_cow_block(trans, root, child, mid, 0, &child, |
| BTRFS_NESTING_COW); |
| if (ret) { |
| btrfs_tree_unlock(child); |
| free_extent_buffer(child); |
| goto out; |
| } |
| |
| ret = btrfs_tree_mod_log_insert_root(root->node, child, true); |
| if (ret < 0) { |
| btrfs_tree_unlock(child); |
| free_extent_buffer(child); |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| rcu_assign_pointer(root->node, child); |
| |
| add_root_to_dirty_list(root); |
| btrfs_tree_unlock(child); |
| |
| path->locks[level] = 0; |
| path->nodes[level] = NULL; |
| btrfs_clear_buffer_dirty(trans, mid); |
| btrfs_tree_unlock(mid); |
| /* once for the path */ |
| free_extent_buffer(mid); |
| |
| root_sub_used_bytes(root); |
| ret = btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1); |
| /* once for the root ptr */ |
| free_extent_buffer_stale(mid); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| return 0; |
| } |
| if (btrfs_header_nritems(mid) > |
| BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4) |
| return 0; |
| |
| if (pslot) { |
| left = btrfs_read_node_slot(parent, pslot - 1); |
| if (IS_ERR(left)) { |
| ret = PTR_ERR(left); |
| left = NULL; |
| goto out; |
| } |
| |
| btrfs_tree_lock_nested(left, BTRFS_NESTING_LEFT); |
| wret = btrfs_cow_block(trans, root, left, |
| parent, pslot - 1, &left, |
| BTRFS_NESTING_LEFT_COW); |
| if (wret) { |
| ret = wret; |
| goto out; |
| } |
| } |
| |
| if (pslot + 1 < btrfs_header_nritems(parent)) { |
| right = btrfs_read_node_slot(parent, pslot + 1); |
| if (IS_ERR(right)) { |
| ret = PTR_ERR(right); |
| right = NULL; |
| goto out; |
| } |
| |
| btrfs_tree_lock_nested(right, BTRFS_NESTING_RIGHT); |
| wret = btrfs_cow_block(trans, root, right, |
| parent, pslot + 1, &right, |
| BTRFS_NESTING_RIGHT_COW); |
| if (wret) { |
| ret = wret; |
| goto out; |
| } |
| } |
| |
| /* first, try to make some room in the middle buffer */ |
| if (left) { |
| orig_slot += btrfs_header_nritems(left); |
| wret = push_node_left(trans, left, mid, 1); |
| if (wret < 0) |
| ret = wret; |
| } |
| |
| /* |
| * then try to empty the right most buffer into the middle |
| */ |
| if (right) { |
| wret = push_node_left(trans, mid, right, 1); |
| if (wret < 0 && wret != -ENOSPC) |
| ret = wret; |
| if (btrfs_header_nritems(right) == 0) { |
| btrfs_clear_buffer_dirty(trans, right); |
| btrfs_tree_unlock(right); |
| ret = btrfs_del_ptr(trans, root, path, level + 1, pslot + 1); |
| if (ret < 0) { |
| free_extent_buffer_stale(right); |
| right = NULL; |
| goto out; |
| } |
| root_sub_used_bytes(root); |
| ret = btrfs_free_tree_block(trans, btrfs_root_id(root), |
| right, 0, 1); |
| free_extent_buffer_stale(right); |
| right = NULL; |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| } else { |
| struct btrfs_disk_key right_key; |
| btrfs_node_key(right, &right_key, 0); |
| ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1, |
| BTRFS_MOD_LOG_KEY_REPLACE); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| btrfs_set_node_key(parent, &right_key, pslot + 1); |
| btrfs_mark_buffer_dirty(trans, parent); |
| } |
| } |
| if (btrfs_header_nritems(mid) == 1) { |
| /* |
| * we're not allowed to leave a node with one item in the |
| * tree during a delete. A deletion from lower in the tree |
| * could try to delete the only pointer in this node. |
| * So, pull some keys from the left. |
| * There has to be a left pointer at this point because |
| * otherwise we would have pulled some pointers from the |
| * right |
| */ |
| if (unlikely(!left)) { |
| btrfs_crit(fs_info, |
| "missing left child when middle child only has 1 item, parent bytenr %llu level %d mid bytenr %llu root %llu", |
| parent->start, btrfs_header_level(parent), |
| mid->start, btrfs_root_id(root)); |
| ret = -EUCLEAN; |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| wret = balance_node_right(trans, mid, left); |
| if (wret < 0) { |
| ret = wret; |
| goto out; |
| } |
| if (wret == 1) { |
| wret = push_node_left(trans, left, mid, 1); |
| if (wret < 0) |
| ret = wret; |
| } |
| BUG_ON(wret == 1); |
| } |
| if (btrfs_header_nritems(mid) == 0) { |
| btrfs_clear_buffer_dirty(trans, mid); |
| btrfs_tree_unlock(mid); |
| ret = btrfs_del_ptr(trans, root, path, level + 1, pslot); |
| if (ret < 0) { |
| free_extent_buffer_stale(mid); |
| mid = NULL; |
| goto out; |
| } |
| root_sub_used_bytes(root); |
| ret = btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1); |
| free_extent_buffer_stale(mid); |
| mid = NULL; |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| } else { |
| /* update the parent key to reflect our changes */ |
| struct btrfs_disk_key mid_key; |
| btrfs_node_key(mid, &mid_key, 0); |
| ret = btrfs_tree_mod_log_insert_key(parent, pslot, |
| BTRFS_MOD_LOG_KEY_REPLACE); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| goto out; |
| } |
| btrfs_set_node_key(parent, &mid_key, pslot); |
| btrfs_mark_buffer_dirty(trans, parent); |
| } |
| |
| /* update the path */ |
| if (left) { |
| if (btrfs_header_nritems(left) > orig_slot) { |
| atomic_inc(&left->refs); |
| /* left was locked after cow */ |
| path->nodes[level] = left; |
| path->slots[level + 1] -= 1; |
| path->slots[level] = orig_slot; |
| if (mid) { |
| btrfs_tree_unlock(mid); |
| free_extent_buffer(mid); |
| } |
| } else { |
| orig_slot -= btrfs_header_nritems(left); |
| path->slots[level] = orig_slot; |
| } |
| } |
| /* double check we haven't messed things up */ |
| if (orig_ptr != |
| btrfs_node_blockptr(path->nodes[level], path->slots[level])) |
| BUG(); |
| out: |
| if (right) { |
| btrfs_tree_unlock(right); |
| free_extent_buffer(right); |
| } |
| if (left) { |
| if (path->nodes[level] != left) |
| btrfs_tree_unlock(left); |
| free_extent_buffer(left); |
| } |
| return ret; |
| } |
| |
| /* Node balancing for insertion. Here we only split or push nodes around |
| * when they are completely full. This is also done top down, so we |
| * have to be pessimistic. |
| */ |
| static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct btrfs_path *path, int level) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct extent_buffer *right = NULL; |
| struct extent_buffer *mid; |
| struct extent_buffer *left = NULL; |
| struct extent_buffer *parent = NULL; |
| int ret = 0; |
| int wret; |
| int pslot; |
| int orig_slot = path->slots[level]; |
| |
| if (level == 0) |
| return 1; |
| |
| mid = path->nodes[level]; |
| WARN_ON(btrfs_header_generation(mid) != trans->transid); |
| |
| if (level < BTRFS_MAX_LEVEL - 1) { |
| parent = path->nodes[level + 1]; |
| pslot = path->slots[level + 1]; |
| } |
| |
| if (!parent) |
| return 1; |
| |
| /* first, try to make some room in the middle buffer */ |
| if (pslot) { |
| u32 left_nr; |
| |
| left = btrfs_read_node_slot(parent, pslot - 1); |
| if (IS_ERR(left)) |
| return PTR_ERR(left); |
| |
| btrfs_tree_lock_nested(left, BTRFS_NESTING_LEFT); |
| |
| left_nr = btrfs_header_nritems(left); |
| if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) { |
| wret = 1; |
| } else { |
| ret = btrfs_cow_block(trans, root, left, parent, |
| pslot - 1, &left, |
| BTRFS_NESTING_LEFT_COW); |
| if (ret) |
| wret = 1; |
| else { |
| wret = push_node_left(trans, left, mid, 0); |
| } |
| } |
| if (wret < 0) |
| ret = wret; |
| if (wret == 0) { |
| struct btrfs_disk_key disk_key; |
| orig_slot += left_nr; |
| btrfs_node_key(mid, &disk_key, 0); |
| ret = btrfs_tree_mod_log_insert_key(parent, pslot, |
| BTRFS_MOD_LOG_KEY_REPLACE); |
| if (ret < 0) { |
| btrfs_tree_unlock(left); |
| free_extent_buffer(left); |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| btrfs_set_node_key(parent, &disk_key, pslot); |
| btrfs_mark_buffer_dirty(trans, parent); |
| if (btrfs_header_nritems(left) > orig_slot) { |
| path->nodes[level] = left; |
| path->slots[level + 1] -= 1; |
| path->slots[level] = orig_slot; |
| btrfs_tree_unlock(mid); |
| free_extent_buffer(mid); |
| } else { |
| orig_slot -= |
| btrfs_header_nritems(left); |
| path->slots[level] = orig_slot; |
| btrfs_tree_unlock(left); |
| free_extent_buffer(left); |
| } |
| return 0; |
| } |
| btrfs_tree_unlock(left); |
| free_extent_buffer(left); |
| } |
| |
| /* |
| * then try to empty the right most buffer into the middle |
| */ |
| if (pslot + 1 < btrfs_header_nritems(parent)) { |
| u32 right_nr; |
| |
| right = btrfs_read_node_slot(parent, pslot + 1); |
| if (IS_ERR(right)) |
| return PTR_ERR(right); |
| |
| btrfs_tree_lock_nested(right, BTRFS_NESTING_RIGHT); |
| |
| right_nr = btrfs_header_nritems(right); |
| if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) { |
| wret = 1; |
| } else { |
| ret = btrfs_cow_block(trans, root, right, |
| parent, pslot + 1, |
| &right, BTRFS_NESTING_RIGHT_COW); |
| if (ret) |
| wret = 1; |
| else { |
| wret = balance_node_right(trans, right, mid); |
| } |
| } |
| if (wret < 0) |
| ret = wret; |
| if (wret == 0) { |
| struct btrfs_disk_key disk_key; |
| |
| btrfs_node_key(right, &disk_key, 0); |
| ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1, |
| BTRFS_MOD_LOG_KEY_REPLACE); |
| if (ret < 0) { |
| btrfs_tree_unlock(right); |
| free_extent_buffer(right); |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| btrfs_set_node_key(parent, &disk_key, pslot + 1); |
| btrfs_mark_buffer_dirty(trans, parent); |
| |
| if (btrfs_header_nritems(mid) <= orig_slot) { |
| path->nodes[level] = right; |
| path->slots[level + 1] += 1; |
| path->slots[level] = orig_slot - |
| btrfs_header_nritems(mid); |
| btrfs_tree_unlock(mid); |
| free_extent_buffer(mid); |
| } else { |
| btrfs_tree_unlock(right); |
| free_extent_buffer(right); |
| } |
| return 0; |
| } |
| btrfs_tree_unlock(right); |
| free_extent_buffer(right); |
| } |
| return 1; |
| } |
| |
| /* |
| * readahead one full node of leaves, finding things that are close |
| * to the block in 'slot', and triggering ra on them. |
| */ |
| static void reada_for_search(struct btrfs_fs_info *fs_info, |
| struct btrfs_path *path, |
| int level, int slot, u64 objectid) |
| { |
| struct extent_buffer *node; |
| struct btrfs_disk_key disk_key; |
| u32 nritems; |
| u64 search; |
| u64 target; |
| u64 nread = 0; |
| u64 nread_max; |
| u32 nr; |
| u32 blocksize; |
| u32 nscan = 0; |
| |
| if (level != 1 && path->reada != READA_FORWARD_ALWAYS) |
| return; |
| |
| if (!path->nodes[level]) |
| return; |
| |
| node = path->nodes[level]; |
| |
| /* |
| * Since the time between visiting leaves is much shorter than the time |
| * between visiting nodes, limit read ahead of nodes to 1, to avoid too |
| * much IO at once (possibly random). |
| */ |
| if (path->reada == READA_FORWARD_ALWAYS) { |
| if (level > 1) |
| nread_max = node->fs_info->nodesize; |
| else |
| nread_max = SZ_128K; |
| } else { |
| nread_max = SZ_64K; |
| } |
| |
| search = btrfs_node_blockptr(node, slot); |
| blocksize = fs_info->nodesize; |
| if (path->reada != READA_FORWARD_ALWAYS) { |
| struct extent_buffer *eb; |
| |
| eb = find_extent_buffer(fs_info, search); |
| if (eb) { |
| free_extent_buffer(eb); |
| return; |
| } |
| } |
| |
| target = search; |
| |
| nritems = btrfs_header_nritems(node); |
| nr = slot; |
| |
| while (1) { |
| if (path->reada == READA_BACK) { |
| if (nr == 0) |
| break; |
| nr--; |
| } else if (path->reada == READA_FORWARD || |
| path->reada == READA_FORWARD_ALWAYS) { |
| nr++; |
| if (nr >= nritems) |
| break; |
| } |
| if (path->reada == READA_BACK && objectid) { |
| btrfs_node_key(node, &disk_key, nr); |
| if (btrfs_disk_key_objectid(&disk_key) != objectid) |
| break; |
| } |
| search = btrfs_node_blockptr(node, nr); |
| if (path->reada == READA_FORWARD_ALWAYS || |
| (search <= target && target - search <= 65536) || |
| (search > target && search - target <= 65536)) { |
| btrfs_readahead_node_child(node, nr); |
| nread += blocksize; |
| } |
| nscan++; |
| if (nread > nread_max || nscan > 32) |
| break; |
| } |
| } |
| |
| static noinline void reada_for_balance(struct btrfs_path *path, int level) |
| { |
| struct extent_buffer *parent; |
| int slot; |
| int nritems; |
| |
| parent = path->nodes[level + 1]; |
| if (!parent) |
| return; |
| |
| nritems = btrfs_header_nritems(parent); |
| slot = path->slots[level + 1]; |
| |
| if (slot > 0) |
| btrfs_readahead_node_child(parent, slot - 1); |
| if (slot + 1 < nritems) |
| btrfs_readahead_node_child(parent, slot + 1); |
| } |
| |
| |
| /* |
| * when we walk down the tree, it is usually safe to unlock the higher layers |
| * in the tree. The exceptions are when our path goes through slot 0, because |
| * operations on the tree might require changing key pointers higher up in the |
| * tree. |
| * |
| * callers might also have set path->keep_locks, which tells this code to keep |
| * the lock if the path points to the last slot in the block. This is part of |
| * walking through the tree, and selecting the next slot in the higher block. |
| * |
| * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so |
| * if lowest_unlock is 1, level 0 won't be unlocked |
| */ |
| static noinline void unlock_up(struct btrfs_path *path, int level, |
| int lowest_unlock, int min_write_lock_level, |
| int *write_lock_level) |
| { |
| int i; |
| int skip_level = level; |
| bool check_skip = true; |
| |
| for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| if (!path->nodes[i]) |
| break; |
| if (!path->locks[i]) |
| break; |
| |
| if (check_skip) { |
| if (path->slots[i] == 0) { |
| skip_level = i + 1; |
| continue; |
| } |
| |
| if (path->keep_locks) { |
| u32 nritems; |
| |
| nritems = btrfs_header_nritems(path->nodes[i]); |
| if (nritems < 1 || path->slots[i] >= nritems - 1) { |
| skip_level = i + 1; |
| continue; |
| } |
| } |
| } |
| |
| if (i >= lowest_unlock && i > skip_level) { |
| check_skip = false; |
| btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]); |
| path->locks[i] = 0; |
| if (write_lock_level && |
| i > min_write_lock_level && |
| i <= *write_lock_level) { |
| *write_lock_level = i - 1; |
| } |
| } |
| } |
| } |
| |
| /* |
| * Helper function for btrfs_search_slot() and other functions that do a search |
| * on a btree. The goal is to find a tree block in the cache (the radix tree at |
| * fs_info->buffer_radix), but if we can't find it, or it's not up to date, read |
| * its pages from disk. |
| * |
| * Returns -EAGAIN, with the path unlocked, if the caller needs to repeat the |
| * whole btree search, starting again from the current root node. |
| */ |
| static int |
| read_block_for_search(struct btrfs_root *root, struct btrfs_path *p, |
| struct extent_buffer **eb_ret, int level, int slot, |
| const struct btrfs_key *key) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct btrfs_tree_parent_check check = { 0 }; |
| u64 blocknr; |
| u64 gen; |
| struct extent_buffer *tmp; |
| int ret; |
| int parent_level; |
| bool unlock_up; |
| |
| unlock_up = ((level + 1 < BTRFS_MAX_LEVEL) && p->locks[level + 1]); |
| blocknr = btrfs_node_blockptr(*eb_ret, slot); |
| gen = btrfs_node_ptr_generation(*eb_ret, slot); |
| parent_level = btrfs_header_level(*eb_ret); |
| btrfs_node_key_to_cpu(*eb_ret, &check.first_key, slot); |
| check.has_first_key = true; |
| check.level = parent_level - 1; |
| check.transid = gen; |
| check.owner_root = btrfs_root_id(root); |
| |
| /* |
| * If we need to read an extent buffer from disk and we are holding locks |
| * on upper level nodes, we unlock all the upper nodes before reading the |
| * extent buffer, and then return -EAGAIN to the caller as it needs to |
| * restart the search. We don't release the lock on the current level |
| * because we need to walk this node to figure out which blocks to read. |
| */ |
| tmp = find_extent_buffer(fs_info, blocknr); |
| if (tmp) { |
| if (p->reada == READA_FORWARD_ALWAYS) |
| reada_for_search(fs_info, p, level, slot, key->objectid); |
| |
| /* first we do an atomic uptodate check */ |
| if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) { |
| /* |
| * Do extra check for first_key, eb can be stale due to |
| * being cached, read from scrub, or have multiple |
| * parents (shared tree blocks). |
| */ |
| if (btrfs_verify_level_key(tmp, |
| parent_level - 1, &check.first_key, gen)) { |
| free_extent_buffer(tmp); |
| return -EUCLEAN; |
| } |
| *eb_ret = tmp; |
| return 0; |
| } |
| |
| if (p->nowait) { |
| free_extent_buffer(tmp); |
| return -EAGAIN; |
| } |
| |
| if (unlock_up) |
| btrfs_unlock_up_safe(p, level + 1); |
| |
| /* now we're allowed to do a blocking uptodate check */ |
| ret = btrfs_read_extent_buffer(tmp, &check); |
| if (ret) { |
| free_extent_buffer(tmp); |
| btrfs_release_path(p); |
| return ret; |
| } |
| |
| if (unlock_up) |
| ret = -EAGAIN; |
| |
| goto out; |
| } else if (p->nowait) { |
| return -EAGAIN; |
| } |
| |
| if (unlock_up) { |
| btrfs_unlock_up_safe(p, level + 1); |
| ret = -EAGAIN; |
| } else { |
| ret = 0; |
| } |
| |
| if (p->reada != READA_NONE) |
| reada_for_search(fs_info, p, level, slot, key->objectid); |
| |
| tmp = read_tree_block(fs_info, blocknr, &check); |
| if (IS_ERR(tmp)) { |
| btrfs_release_path(p); |
| return PTR_ERR(tmp); |
| } |
| /* |
| * If the read above didn't mark this buffer up to date, |
| * it will never end up being up to date. Set ret to EIO now |
| * and give up so that our caller doesn't loop forever |
| * on our EAGAINs. |
| */ |
| if (!extent_buffer_uptodate(tmp)) |
| ret = -EIO; |
| |
| out: |
| if (ret == 0) { |
| *eb_ret = tmp; |
| } else { |
| free_extent_buffer(tmp); |
| btrfs_release_path(p); |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * helper function for btrfs_search_slot. This does all of the checks |
| * for node-level blocks and does any balancing required based on |
| * the ins_len. |
| * |
| * If no extra work was required, zero is returned. If we had to |
| * drop the path, -EAGAIN is returned and btrfs_search_slot must |
| * start over |
| */ |
| static int |
| setup_nodes_for_search(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, struct btrfs_path *p, |
| struct extent_buffer *b, int level, int ins_len, |
| int *write_lock_level) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| int ret = 0; |
| |
| if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >= |
| BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) { |
| |
| if (*write_lock_level < level + 1) { |
| *write_lock_level = level + 1; |
| btrfs_release_path(p); |
| return -EAGAIN; |
| } |
| |
| reada_for_balance(p, level); |
| ret = split_node(trans, root, p, level); |
| |
| b = p->nodes[level]; |
| } else if (ins_len < 0 && btrfs_header_nritems(b) < |
| BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 2) { |
| |
| if (*write_lock_level < level + 1) { |
| *write_lock_level = level + 1; |
| btrfs_release_path(p); |
| return -EAGAIN; |
| } |
| |
| reada_for_balance(p, level); |
| ret = balance_level(trans, root, p, level); |
| if (ret) |
| return ret; |
| |
| b = p->nodes[level]; |
| if (!b) { |
| btrfs_release_path(p); |
| return -EAGAIN; |
| } |
| BUG_ON(btrfs_header_nritems(b) == 1); |
| } |
| return ret; |
| } |
| |
| int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path, |
| u64 iobjectid, u64 ioff, u8 key_type, |
| struct btrfs_key *found_key) |
| { |
| int ret; |
| struct btrfs_key key; |
| struct extent_buffer *eb; |
| |
| ASSERT(path); |
| ASSERT(found_key); |
| |
| key.type = key_type; |
| key.objectid = iobjectid; |
| key.offset = ioff; |
| |
| ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); |
| if (ret < 0) |
| return ret; |
| |
| eb = path->nodes[0]; |
| if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { |
| ret = btrfs_next_leaf(fs_root, path); |
| if (ret) |
| return ret; |
| eb = path->nodes[0]; |
| } |
| |
| btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); |
| if (found_key->type != key.type || |
| found_key->objectid != key.objectid) |
| return 1; |
| |
| return 0; |
| } |
| |
| static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root, |
| struct btrfs_path *p, |
| int write_lock_level) |
| { |
| struct extent_buffer *b; |
| int root_lock = 0; |
| int level = 0; |
| |
| if (p->search_commit_root) { |
| b = root->commit_root; |
| atomic_inc(&b->refs); |
| level = btrfs_header_level(b); |
| /* |
| * Ensure that all callers have set skip_locking when |
| * p->search_commit_root = 1. |
| */ |
| ASSERT(p->skip_locking == 1); |
| |
| goto out; |
| } |
| |
| if (p->skip_locking) { |
| b = btrfs_root_node(root); |
| level = btrfs_header_level(b); |
| goto out; |
| } |
| |
| /* We try very hard to do read locks on the root */ |
| root_lock = BTRFS_READ_LOCK; |
| |
| /* |
| * If the level is set to maximum, we can skip trying to get the read |
| * lock. |
| */ |
| if (write_lock_level < BTRFS_MAX_LEVEL) { |
| /* |
| * We don't know the level of the root node until we actually |
| * have it read locked |
| */ |
| if (p->nowait) { |
| b = btrfs_try_read_lock_root_node(root); |
| if (IS_ERR(b)) |
| return b; |
| } else { |
| b = btrfs_read_lock_root_node(root); |
| } |
| level = btrfs_header_level(b); |
| if (level > write_lock_level) |
| goto out; |
| |
| /* Whoops, must trade for write lock */ |
| btrfs_tree_read_unlock(b); |
| free_extent_buffer(b); |
| } |
| |
| b = btrfs_lock_root_node(root); |
| root_lock = BTRFS_WRITE_LOCK; |
| |
| /* The level might have changed, check again */ |
| level = btrfs_header_level(b); |
| |
| out: |
| /* |
| * The root may have failed to write out at some point, and thus is no |
| * longer valid, return an error in this case. |
| */ |
| if (!extent_buffer_uptodate(b)) { |
| if (root_lock) |
| btrfs_tree_unlock_rw(b, root_lock); |
| free_extent_buffer(b); |
| return ERR_PTR(-EIO); |
| } |
| |
| p->nodes[level] = b; |
| if (!p->skip_locking) |
| p->locks[level] = root_lock; |
| /* |
| * Callers are responsible for dropping b's references. |
| */ |
| return b; |
| } |
| |
| /* |
| * Replace the extent buffer at the lowest level of the path with a cloned |
| * version. The purpose is to be able to use it safely, after releasing the |
| * commit root semaphore, even if relocation is happening in parallel, the |
| * transaction used for relocation is committed and the extent buffer is |
| * reallocated in the next transaction. |
| * |
| * This is used in a context where the caller does not prevent transaction |
| * commits from happening, either by holding a transaction handle or holding |
| * some lock, while it's doing searches through a commit root. |
| * At the moment it's only used for send operations. |
| */ |
| static int finish_need_commit_sem_search(struct btrfs_path *path) |
| { |
| const int i = path->lowest_level; |
| const int slot = path->slots[i]; |
| struct extent_buffer *lowest = path->nodes[i]; |
| struct extent_buffer *clone; |
| |
| ASSERT(path->need_commit_sem); |
| |
| if (!lowest) |
| return 0; |
| |
| lockdep_assert_held_read(&lowest->fs_info->commit_root_sem); |
| |
| clone = btrfs_clone_extent_buffer(lowest); |
| if (!clone) |
| return -ENOMEM; |
| |
| btrfs_release_path(path); |
| path->nodes[i] = clone; |
| path->slots[i] = slot; |
| |
| return 0; |
| } |
| |
| static inline int search_for_key_slot(struct extent_buffer *eb, |
| int search_low_slot, |
| const struct btrfs_key *key, |
| int prev_cmp, |
| int *slot) |
| { |
| /* |
| * If a previous call to btrfs_bin_search() on a parent node returned an |
| * exact match (prev_cmp == 0), we can safely assume the target key will |
| * always be at slot 0 on lower levels, since each key pointer |
| * (struct btrfs_key_ptr) refers to the lowest key accessible from the |
| * subtree it points to. Thus we can skip searching lower levels. |
| */ |
| if (prev_cmp == 0) { |
| *slot = 0; |
| return 0; |
| } |
| |
| return btrfs_bin_search(eb, search_low_slot, key, slot); |
| } |
| |
| static int search_leaf(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| const struct btrfs_key *key, |
| struct btrfs_path *path, |
| int ins_len, |
| int prev_cmp) |
| { |
| struct extent_buffer *leaf = path->nodes[0]; |
| int leaf_free_space = -1; |
| int search_low_slot = 0; |
| int ret; |
| bool do_bin_search = true; |
| |
| /* |
| * If we are doing an insertion, the leaf has enough free space and the |
| * destination slot for the key is not slot 0, then we can unlock our |
| * write lock on the parent, and any other upper nodes, before doing the |
| * binary search on the leaf (with search_for_key_slot()), allowing other |
| * tasks to lock the parent and any other upper nodes. |
| */ |
| if (ins_len > 0) { |
| /* |
| * Cache the leaf free space, since we will need it later and it |
| * will not change until then. |
| */ |
| leaf_free_space = btrfs_leaf_free_space(leaf); |
| |
| /* |
| * !path->locks[1] means we have a single node tree, the leaf is |
| * the root of the tree. |
| */ |
| if (path->locks[1] && leaf_free_space >= ins_len) { |
| struct btrfs_disk_key first_key; |
| |
| ASSERT(btrfs_header_nritems(leaf) > 0); |
| btrfs_item_key(leaf, &first_key, 0); |
| |
| /* |
| * Doing the extra comparison with the first key is cheap, |
| * taking into account that the first key is very likely |
| * already in a cache line because it immediately follows |
| * the extent buffer's header and we have recently accessed |
| * the header's level field. |
| */ |
| ret = btrfs_comp_keys(&first_key, key); |
| if (ret < 0) { |
| /* |
| * The first key is smaller than the key we want |
| * to insert, so we are safe to unlock all upper |
| * nodes and we have to do the binary search. |
| * |
| * We do use btrfs_unlock_up_safe() and not |
| * unlock_up() because the later does not unlock |
| * nodes with a slot of 0 - we can safely unlock |
| * any node even if its slot is 0 since in this |
| * case the key does not end up at slot 0 of the |
| * leaf and there's no need to split the leaf. |
| */ |
| btrfs_unlock_up_safe(path, 1); |
| search_low_slot = 1; |
| } else { |
| /* |
| * The first key is >= then the key we want to |
| * insert, so we can skip the binary search as |
| * the target key will be at slot 0. |
| * |
| * We can not unlock upper nodes when the key is |
| * less than the first key, because we will need |
| * to update the key at slot 0 of the parent node |
| * and possibly of other upper nodes too. |
| * If the key matches the first key, then we can |
| * unlock all the upper nodes, using |
| * btrfs_unlock_up_safe() instead of unlock_up() |
| * as stated above. |
| */ |
| if (ret == 0) |
| btrfs_unlock_up_safe(path, 1); |
| /* |
| * ret is already 0 or 1, matching the result of |
| * a btrfs_bin_search() call, so there is no need |
| * to adjust it. |
| */ |
| do_bin_search = false; |
| path->slots[0] = 0; |
| } |
| } |
| } |
| |
| if (do_bin_search) { |
| ret = search_for_key_slot(leaf, search_low_slot, key, |
| prev_cmp, &path->slots[0]); |
| if (ret < 0) |
| return ret; |
| } |
| |
| if (ins_len > 0) { |
| /* |
| * Item key already exists. In this case, if we are allowed to |
| * insert the item (for example, in dir_item case, item key |
| * collision is allowed), it will be merged with the original |
| * item. Only the item size grows, no new btrfs item will be |
| * added. If search_for_extension is not set, ins_len already |
| * accounts the size btrfs_item, deduct it here so leaf space |
| * check will be correct. |
| */ |
| if (ret == 0 && !path->search_for_extension) { |
| ASSERT(ins_len >= sizeof(struct btrfs_item)); |
| ins_len -= sizeof(struct btrfs_item); |
| } |
| |
| ASSERT(leaf_free_space >= 0); |
| |
| if (leaf_free_space < ins_len) { |
| int err; |
| |
| err = split_leaf(trans, root, key, path, ins_len, |
| (ret == 0)); |
| ASSERT(err <= 0); |
| if (WARN_ON(err > 0)) |
| err = -EUCLEAN; |
| if (err) |
| ret = err; |
| } |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * Look for a key in a tree and perform necessary modifications to preserve |
| * tree invariants. |
| * |
| * @trans: Handle of transaction, used when modifying the tree |
| * @p: Holds all btree nodes along the search path |
| * @root: The root node of the tree |
| * @key: The key we are looking for |
| * @ins_len: Indicates purpose of search: |
| * >0 for inserts it's size of item inserted (*) |
| * <0 for deletions |
| * 0 for plain searches, not modifying the tree |
| * |
| * (*) If size of item inserted doesn't include |
| * sizeof(struct btrfs_item), then p->search_for_extension must |
| * be set. |
| * @cow: boolean should CoW operations be performed. Must always be 1 |
| * when modifying the tree. |
| * |
| * If @ins_len > 0, nodes and leaves will be split as we walk down the tree. |
| * If @ins_len < 0, nodes will be merged as we walk down the tree (if possible) |
| * |
| * If @key is found, 0 is returned and you can find the item in the leaf level |
| * of the path (level 0) |
| * |
| * If @key isn't found, 1 is returned and the leaf level of the path (level 0) |
| * points to the slot where it should be inserted |
| * |
| * If an error is encountered while searching the tree a negative error number |
| * is returned |
| */ |
| int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
| const struct btrfs_key *key, struct btrfs_path *p, |
| int ins_len, int cow) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct extent_buffer *b; |
| int slot; |
| int ret; |
| int err; |
| int level; |
| int lowest_unlock = 1; |
| /* everything at write_lock_level or lower must be write locked */ |
| int write_lock_level = 0; |
| u8 lowest_level = 0; |
| int min_write_lock_level; |
| int prev_cmp; |
| |
| might_sleep(); |
| |
| lowest_level = p->lowest_level; |
| WARN_ON(lowest_level && ins_len > 0); |
| WARN_ON(p->nodes[0] != NULL); |
| BUG_ON(!cow && ins_len); |
| |
| /* |
| * For now only allow nowait for read only operations. There's no |
| * strict reason why we can't, we just only need it for reads so it's |
| * only implemented for reads. |
| */ |
| ASSERT(!p->nowait || !cow); |
| |
| if (ins_len < 0) { |
| lowest_unlock = 2; |
| |
| /* when we are removing items, we might have to go up to level |
| * two as we update tree pointers Make sure we keep write |
| * for those levels as well |
| */ |
| write_lock_level = 2; |
| } else if (ins_len > 0) { |
| /* |
| * for inserting items, make sure we have a write lock on |
| * level 1 so we can update keys |
| */ |
| write_lock_level = 1; |
| } |
| |
| if (!cow) |
| write_lock_level = -1; |
| |
| if (cow && (p->keep_locks || p->lowest_level)) |
| write_lock_level = BTRFS_MAX_LEVEL; |
| |
| min_write_lock_level = write_lock_level; |
| |
| if (p->need_commit_sem) { |
| ASSERT(p->search_commit_root); |
| if (p->nowait) { |
| if (!down_read_trylock(&fs_info->commit_root_sem)) |
| return -EAGAIN; |
| } else { |
| down_read(&fs_info->commit_root_sem); |
| } |
| } |
| |
| again: |
| prev_cmp = -1; |
| b = btrfs_search_slot_get_root(root, p, write_lock_level); |
| if (IS_ERR(b)) { |
| ret = PTR_ERR(b); |
| goto done; |
| } |
| |
| while (b) { |
| int dec = 0; |
| |
| level = btrfs_header_level(b); |
| |
| if (cow) { |
| bool last_level = (level == (BTRFS_MAX_LEVEL - 1)); |
| |
| /* |
| * if we don't really need to cow this block |
| * then we don't want to set the path blocking, |
| * so we test it here |
| */ |
| if (!should_cow_block(trans, root, b)) |
| goto cow_done; |
| |
| /* |
| * must have write locks on this node and the |
| * parent |
| */ |
| if (level > write_lock_level || |
| (level + 1 > write_lock_level && |
| level + 1 < BTRFS_MAX_LEVEL && |
| p->nodes[level + 1])) { |
| write_lock_level = level + 1; |
| btrfs_release_path(p); |
| goto again; |
| } |
| |
| if (last_level) |
| err = btrfs_cow_block(trans, root, b, NULL, 0, |
| &b, |
| BTRFS_NESTING_COW); |
| else |
| err = btrfs_cow_block(trans, root, b, |
| p->nodes[level + 1], |
| p->slots[level + 1], &b, |
| BTRFS_NESTING_COW); |
| if (err) { |
| ret = err; |
| goto done; |
| } |
| } |
| cow_done: |
| p->nodes[level] = b; |
| |
| /* |
| * we have a lock on b and as long as we aren't changing |
| * the tree, there is no way to for the items in b to change. |
| * It is safe to drop the lock on our parent before we |
| * go through the expensive btree search on b. |
| * |
| * If we're inserting or deleting (ins_len != 0), then we might |
| * be changing slot zero, which may require changing the parent. |
| * So, we can't drop the lock until after we know which slot |
| * we're operating on. |
| */ |
| if (!ins_len && !p->keep_locks) { |
| int u = level + 1; |
| |
| if (u < BTRFS_MAX_LEVEL && p->locks[u]) { |
| btrfs_tree_unlock_rw(p->nodes[u], p->locks[u]); |
| p->locks[u] = 0; |
| } |
| } |
| |
| if (level == 0) { |
| if (ins_len > 0) |
| ASSERT(write_lock_level >= 1); |
| |
| ret = search_leaf(trans, root, key, p, ins_len, prev_cmp); |
| if (!p->search_for_split) |
| unlock_up(p, level, lowest_unlock, |
| min_write_lock_level, NULL); |
| goto done; |
| } |
| |
| ret = search_for_key_slot(b, 0, key, prev_cmp, &slot); |
| if (ret < 0) |
| goto done; |
| prev_cmp = ret; |
| |
| if (ret && slot > 0) { |
| dec = 1; |
| slot--; |
| } |
| p->slots[level] = slot; |
| err = setup_nodes_for_search(trans, root, p, b, level, ins_len, |
| &write_lock_level); |
| if (err == -EAGAIN) |
| goto again; |
| if (err) { |
| ret = err; |
| goto done; |
| } |
| b = p->nodes[level]; |
| slot = p->slots[level]; |
| |
| /* |
| * Slot 0 is special, if we change the key we have to update |
| * the parent pointer which means we must have a write lock on |
| * the parent |
| */ |
| if (slot == 0 && ins_len && write_lock_level < level + 1) { |
| write_lock_level = level + 1; |
| btrfs_release_path(p); |
| goto again; |
| } |
| |
| unlock_up(p, level, lowest_unlock, min_write_lock_level, |
| &write_lock_level); |
| |
| if (level == lowest_level) { |
| if (dec) |
| p->slots[level]++; |
| goto done; |
| } |
| |
| err = read_block_for_search(root, p, &b, level, slot, key); |
| if (err == -EAGAIN) |
| goto again; |
| if (err) { |
| ret = err; |
| goto done; |
| } |
| |
| if (!p->skip_locking) { |
| level = btrfs_header_level(b); |
| |
| btrfs_maybe_reset_lockdep_class(root, b); |
| |
| if (level <= write_lock_level) { |
| btrfs_tree_lock(b); |
| p->locks[level] = BTRFS_WRITE_LOCK; |
| } else { |
| if (p->nowait) { |
| if (!btrfs_try_tree_read_lock(b)) { |
| free_extent_buffer(b); |
| ret = -EAGAIN; |
| goto done; |
| } |
| } else { |
| btrfs_tree_read_lock(b); |
| } |
| p->locks[level] = BTRFS_READ_LOCK; |
| } |
| p->nodes[level] = b; |
| } |
| } |
| ret = 1; |
| done: |
| if (ret < 0 && !p->skip_release_on_error) |
| btrfs_release_path(p); |
| |
| if (p->need_commit_sem) { |
| int ret2; |
| |
| ret2 = finish_need_commit_sem_search(p); |
| up_read(&fs_info->commit_root_sem); |
| if (ret2) |
| ret = ret2; |
| } |
| |
| return ret; |
| } |
| ALLOW_ERROR_INJECTION(btrfs_search_slot, ERRNO); |
| |
| /* |
| * Like btrfs_search_slot, this looks for a key in the given tree. It uses the |
| * current state of the tree together with the operations recorded in the tree |
| * modification log to search for the key in a previous version of this tree, as |
| * denoted by the time_seq parameter. |
| * |
| * Naturally, there is no support for insert, delete or cow operations. |
| * |
| * The resulting path and return value will be set up as if we called |
| * btrfs_search_slot at that point in time with ins_len and cow both set to 0. |
| */ |
| int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key, |
| struct btrfs_path *p, u64 time_seq) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct extent_buffer *b; |
| int slot; |
| int ret; |
| int err; |
| int level; |
| int lowest_unlock = 1; |
| u8 lowest_level = 0; |
| |
| lowest_level = p->lowest_level; |
| WARN_ON(p->nodes[0] != NULL); |
| ASSERT(!p->nowait); |
| |
| if (p->search_commit_root) { |
| BUG_ON(time_seq); |
| return btrfs_search_slot(NULL, root, key, p, 0, 0); |
| } |
| |
| again: |
| b = btrfs_get_old_root(root, time_seq); |
| if (!b) { |
| ret = -EIO; |
| goto done; |
| } |
| level = btrfs_header_level(b); |
| p->locks[level] = BTRFS_READ_LOCK; |
| |
| while (b) { |
| int dec = 0; |
| |
| level = btrfs_header_level(b); |
| p->nodes[level] = b; |
| |
| /* |
| * we have a lock on b and as long as we aren't changing |
| * the tree, there is no way to for the items in b to change. |
| * It is safe to drop the lock on our parent before we |
| * go through the expensive btree search on b. |
| */ |
| btrfs_unlock_up_safe(p, level + 1); |
| |
| ret = btrfs_bin_search(b, 0, key, &slot); |
| if (ret < 0) |
| goto done; |
| |
| if (level == 0) { |
| p->slots[level] = slot; |
| unlock_up(p, level, lowest_unlock, 0, NULL); |
| goto done; |
| } |
| |
| if (ret && slot > 0) { |
| dec = 1; |
| slot--; |
| } |
| p->slots[level] = slot; |
| unlock_up(p, level, lowest_unlock, 0, NULL); |
| |
| if (level == lowest_level) { |
| if (dec) |
| p->slots[level]++; |
| goto done; |
| } |
| |
| err = read_block_for_search(root, p, &b, level, slot, key); |
| if (err == -EAGAIN) |
| goto again; |
| if (err) { |
| ret = err; |
| goto done; |
| } |
| |
| level = btrfs_header_level(b); |
| btrfs_tree_read_lock(b); |
| b = btrfs_tree_mod_log_rewind(fs_info, p, b, time_seq); |
| if (!b) { |
| ret = -ENOMEM; |
| goto done; |
| } |
| p->locks[level] = BTRFS_READ_LOCK; |
| p->nodes[level] = b; |
| } |
| ret = 1; |
| done: |
| if (ret < 0) |
| btrfs_release_path(p); |
| |
| return ret; |
| } |
| |
| /* |
| * Search the tree again to find a leaf with smaller keys. |
| * Returns 0 if it found something. |
| * Returns 1 if there are no smaller keys. |
| * Returns < 0 on error. |
| * |
| * This may release the path, and so you may lose any locks held at the |
| * time you call it. |
| */ |
| static int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) |
| { |
| struct btrfs_key key; |
| struct btrfs_key orig_key; |
| struct btrfs_disk_key found_key; |
| int ret; |
| |
| btrfs_item_key_to_cpu(path->nodes[0], &key, 0); |
| orig_key = key; |
| |
| if (key.offset > 0) { |
| key.offset--; |
| } else if (key.type > 0) { |
| key.type--; |
| key.offset = (u64)-1; |
| } else if (key.objectid > 0) { |
| key.objectid--; |
| key.type = (u8)-1; |
| key.offset = (u64)-1; |
| } else { |
| return 1; |
| } |
| |
| btrfs_release_path(path); |
| ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
| if (ret <= 0) |
| return ret; |
| |
| /* |
| * Previous key not found. Even if we were at slot 0 of the leaf we had |
| * before releasing the path and calling btrfs_search_slot(), we now may |
| * be in a slot pointing to the same original key - this can happen if |
| * after we released the path, one of more items were moved from a |
| * sibling leaf into the front of the leaf we had due to an insertion |
| * (see push_leaf_right()). |
| * If we hit this case and our slot is > 0 and just decrement the slot |
| * so that the caller does not process the same key again, which may or |
| * may not break the caller, depending on its logic. |
| */ |
| if (path->slots[0] < btrfs_header_nritems(path->nodes[0])) { |
| btrfs_item_key(path->nodes[0], &found_key, path->slots[0]); |
| ret = btrfs_comp_keys(&found_key, &orig_key); |
| if (ret == 0) { |
| if (path->slots[0] > 0) { |
| path->slots[0]--; |
| return 0; |
| } |
| /* |
| * At slot 0, same key as before, it means orig_key is |
| * the lowest, leftmost, key in the tree. We're done. |
| */ |
| return 1; |
| } |
| } |
| |
| btrfs_item_key(path->nodes[0], &found_key, 0); |
| ret = btrfs_comp_keys(&found_key, &key); |
| /* |
| * We might have had an item with the previous key in the tree right |
| * before we released our path. And after we released our path, that |
| * item might have been pushed to the first slot (0) of the leaf we |
| * were holding due to a tree balance. Alternatively, an item with the |
| * previous key can exist as the only element of a leaf (big fat item). |
| * Therefore account for these 2 cases, so that our callers (like |
| * btrfs_previous_item) don't miss an existing item with a key matching |
| * the previous key we computed above. |
| */ |
| if (ret <= 0) |
| return 0; |
| return 1; |
| } |
| |
| /* |
| * helper to use instead of search slot if no exact match is needed but |
| * instead the next or previous item should be returned. |
| * When find_higher is true, the next higher item is returned, the next lower |
| * otherwise. |
| * When return_any and find_higher are both true, and no higher item is found, |
| * return the next lower instead. |
| * When return_any is true and find_higher is false, and no lower item is found, |
| * return the next higher instead. |
| * It returns 0 if any item is found, 1 if none is found (tree empty), and |
| * < 0 on error |
| */ |
| int btrfs_search_slot_for_read(struct btrfs_root *root, |
| const struct btrfs_key *key, |
| struct btrfs_path *p, int find_higher, |
| int return_any) |
| { |
| int ret; |
| struct extent_buffer *leaf; |
| |
| again: |
| ret = btrfs_search_slot(NULL, root, key, p, 0, 0); |
| if (ret <= 0) |
| return ret; |
| /* |
| * a return value of 1 means the path is at the position where the |
| * item should be inserted. Normally this is the next bigger item, |
| * but in case the previous item is the last in a leaf, path points |
| * to the first free slot in the previous leaf, i.e. at an invalid |
| * item. |
| */ |
| leaf = p->nodes[0]; |
| |
| if (find_higher) { |
| if (p->slots[0] >= btrfs_header_nritems(leaf)) { |
| ret = btrfs_next_leaf(root, p); |
| if (ret <= 0) |
| return ret; |
| if (!return_any) |
| return 1; |
| /* |
| * no higher item found, return the next |
| * lower instead |
| */ |
| return_any = 0; |
| find_higher = 0; |
| btrfs_release_path(p); |
| goto again; |
| } |
| } else { |
| if (p->slots[0] == 0) { |
| ret = btrfs_prev_leaf(root, p); |
| if (ret < 0) |
| return ret; |
| if (!ret) { |
| leaf = p->nodes[0]; |
| if (p->slots[0] == btrfs_header_nritems(leaf)) |
| p->slots[0]--; |
| return 0; |
| } |
| if (!return_any) |
| return 1; |
| /* |
| * no lower item found, return the next |
| * higher instead |
| */ |
| return_any = 0; |
| find_higher = 1; |
| btrfs_release_path(p); |
| goto again; |
| } else { |
| --p->slots[0]; |
| } |
| } |
| return 0; |
| } |
| |
| /* |
| * Execute search and call btrfs_previous_item to traverse backwards if the item |
| * was not found. |
| * |
| * Return 0 if found, 1 if not found and < 0 if error. |
| */ |
| int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key, |
| struct btrfs_path *path) |
| { |
| int ret; |
| |
| ret = btrfs_search_slot(NULL, root, key, path, 0, 0); |
| if (ret > 0) |
| ret = btrfs_previous_item(root, path, key->objectid, key->type); |
| |
| if (ret == 0) |
| btrfs_item_key_to_cpu(path->nodes[0], key, path->slots[0]); |
| |
| return ret; |
| } |
| |
| /* |
| * Search for a valid slot for the given path. |
| * |
| * @root: The root node of the tree. |
| * @key: Will contain a valid item if found. |
| * @path: The starting point to validate the slot. |
| * |
| * Return: 0 if the item is valid |
| * 1 if not found |
| * <0 if error. |
| */ |
| int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key, |
| struct btrfs_path *path) |
| { |
| if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { |
| int ret; |
| |
| ret = btrfs_next_leaf(root, path); |
| if (ret) |
| return ret; |
| } |
| |
| btrfs_item_key_to_cpu(path->nodes[0], key, path->slots[0]); |
| return 0; |
| } |
| |
| /* |
| * adjust the pointers going up the tree, starting at level |
| * making sure the right key of each node is points to 'key'. |
| * This is used after shifting pointers to the left, so it stops |
| * fixing up pointers when a given leaf/node is not in slot 0 of the |
| * higher levels |
| * |
| */ |
| static void fixup_low_keys(struct btrfs_trans_handle *trans, |
| struct btrfs_path *path, |
| struct btrfs_disk_key *key, int level) |
| { |
| int i; |
| struct extent_buffer *t; |
| int ret; |
| |
| for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
| int tslot = path->slots[i]; |
| |
| if (!path->nodes[i]) |
| break; |
| t = path->nodes[i]; |
| ret = btrfs_tree_mod_log_insert_key(t, tslot, |
| BTRFS_MOD_LOG_KEY_REPLACE); |
| BUG_ON(ret < 0); |
| btrfs_set_node_key(t, key, tslot); |
| btrfs_mark_buffer_dirty(trans, path->nodes[i]); |
| if (tslot != 0) |
| break; |
| } |
| } |
| |
| /* |
| * update item key. |
| * |
| * This function isn't completely safe. It's the caller's responsibility |
| * that the new key won't break the order |
| */ |
| void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans, |
| struct btrfs_path *path, |
| const struct btrfs_key *new_key) |
| { |
| struct btrfs_fs_info *fs_info = trans->fs_info; |
| struct btrfs_disk_key disk_key; |
| struct extent_buffer *eb; |
| int slot; |
| |
| eb = path->nodes[0]; |
| slot = path->slots[0]; |
| if (slot > 0) { |
| btrfs_item_key(eb, &disk_key, slot - 1); |
| if (unlikely(btrfs_comp_keys(&disk_key, new_key) >= 0)) { |
| btrfs_print_leaf(eb); |
| btrfs_crit(fs_info, |
| "slot %u key (%llu %u %llu) new key (%llu %u %llu)", |
| slot, btrfs_disk_key_objectid(&disk_key), |
| btrfs_disk_key_type(&disk_key), |
| btrfs_disk_key_offset(&disk_key), |
| new_key->objectid, new_key->type, |
| new_key->offset); |
| BUG(); |
| } |
| } |
| if (slot < btrfs_header_nritems(eb) - 1) { |
| btrfs_item_key(eb, &disk_key, slot + 1); |
| if (unlikely(btrfs_comp_keys(&disk_key, new_key) <= 0)) { |
| btrfs_print_leaf(eb); |
| btrfs_crit(fs_info, |
| "slot %u key (%llu %u %llu) new key (%llu %u %llu)", |
| slot, btrfs_disk_key_objectid(&disk_key), |
| btrfs_disk_key_type(&disk_key), |
| btrfs_disk_key_offset(&disk_key), |
| new_key->objectid, new_key->type, |
| new_key->offset); |
| BUG(); |
| } |
| } |
| |
| btrfs_cpu_key_to_disk(&disk_key, new_key); |
| btrfs_set_item_key(eb, &disk_key, slot); |
| btrfs_mark_buffer_dirty(trans, eb); |
| if (slot == 0) |
| fixup_low_keys(trans, path, &disk_key, 1); |
| } |
| |
| /* |
| * Check key order of two sibling extent buffers. |
| * |
| * Return true if something is wrong. |
| * Return false if everything is fine. |
| * |
| * Tree-checker only works inside one tree block, thus the following |
| * corruption can not be detected by tree-checker: |
| * |
| * Leaf @left | Leaf @right |
| * -------------------------------------------------------------- |
| * | 1 | 2 | 3 | 4 | 5 | f6 | | 7 | 8 | |
| * |
| * Key f6 in leaf @left itself is valid, but not valid when the next |
| * key in leaf @right is 7. |
| * This can only be checked at tree block merge time. |
| * And since tree checker has ensured all key order in each tree block |
| * is correct, we only need to bother the last key of @left and the first |
| * key of @right. |
| */ |
| static bool check_sibling_keys(struct extent_buffer *left, |
| struct extent_buffer *right) |
| { |
| struct btrfs_key left_last; |
| struct btrfs_key right_first; |
| int level = btrfs_header_level(left); |
| int nr_left = btrfs_header_nritems(left); |
| int nr_right = btrfs_header_nritems(right); |
| |
| /* No key to check in one of the tree blocks */ |
| if (!nr_left || !nr_right) |
| return false; |
| |
| if (level) { |
| btrfs_node_key_to_cpu(left, &left_last, nr_left - 1); |
| btrfs_node_key_to_cpu(right, &right_first, 0); |
| } else { |
| btrfs_item_key_to_cpu(left, &left_last, nr_left - 1); |
| btrfs_item_key_to_cpu(right, &right_first, 0); |
| } |
| |
| if (unlikely(btrfs_comp_cpu_keys(&left_last, &right_first) >= 0)) { |
| btrfs_crit(left->fs_info, "left extent buffer:"); |
| btrfs_print_tree(left, false); |
| btrfs_crit(left->fs_info, "right extent buffer:"); |
| btrfs_print_tree(right, false); |
| btrfs_crit(left->fs_info, |
| "bad key order, sibling blocks, left last (%llu %u %llu) right first (%llu %u %llu)", |
| left_last.objectid, left_last.type, |
| left_last.offset, right_first.objectid, |
| right_first.type, right_first.offset); |
| return true; |
| } |
| return false; |
| } |
| |
| /* |
| * try to push data from one node into the next node left in the |
| * tree. |
| * |
| * returns 0 if some ptrs were pushed left, < 0 if there was some horrible |
| * error, and > 0 if there was no room in the left hand block. |
| */ |
| static int push_node_left(struct btrfs_trans_handle *trans, |
| struct extent_buffer *dst, |
| struct extent_buffer *src, int empty) |
| { |
| struct btrfs_fs_info *fs_info = trans->fs_info; |
| int push_items = 0; |
| int src_nritems; |
| int dst_nritems; |
| int ret = 0; |
| |
| src_nritems = btrfs_header_nritems(src); |
| dst_nritems = btrfs_header_nritems(dst); |
| push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems; |
| WARN_ON(btrfs_header_generation(src) != trans->transid); |
| WARN_ON(btrfs_header_generation(dst) != trans->transid); |
| |
| if (!empty && src_nritems <= 8) |
| return 1; |
| |
| if (push_items <= 0) |
| return 1; |
| |
| if (empty) { |
| push_items = min(src_nritems, push_items); |
| if (push_items < src_nritems) { |
| /* leave at least 8 pointers in the node if |
| * we aren't going to empty it |
| */ |
| if (src_nritems - push_items < 8) { |
| if (push_items <= 8) |
| return 1; |
| push_items -= 8; |
| } |
| } |
| } else |
| push_items = min(src_nritems - 8, push_items); |
| |
| /* dst is the left eb, src is the middle eb */ |
| if (check_sibling_keys(dst, src)) { |
| ret = -EUCLEAN; |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| ret = btrfs_tree_mod_log_eb_copy(dst, src, dst_nritems, 0, push_items); |
| if (ret) { |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| copy_extent_buffer(dst, src, |
| btrfs_node_key_ptr_offset(dst, dst_nritems), |
| btrfs_node_key_ptr_offset(src, 0), |
| push_items * sizeof(struct btrfs_key_ptr)); |
| |
| if (push_items < src_nritems) { |
| /* |
| * btrfs_tree_mod_log_eb_copy handles logging the move, so we |
| * don't need to do an explicit tree mod log operation for it. |
| */ |
| memmove_extent_buffer(src, btrfs_node_key_ptr_offset(src, 0), |
| btrfs_node_key_ptr_offset(src, push_items), |
| (src_nritems - push_items) * |
| sizeof(struct btrfs_key_ptr)); |
| } |
| btrfs_set_header_nritems(src, src_nritems - push_items); |
| btrfs_set_header_nritems(dst, dst_nritems + push_items); |
| btrfs_mark_buffer_dirty(trans, src); |
| btrfs_mark_buffer_dirty(trans, dst); |
| |
| return ret; |
| } |
| |
| /* |
| * try to push data from one node into the next node right in the |
| * tree. |
| * |
| * returns 0 if some ptrs were pushed, < 0 if there was some horrible |
| * error, and > 0 if there was no room in the right hand block. |
| * |
| * this will only push up to 1/2 the contents of the left node over |
| */ |
| static int balance_node_right(struct btrfs_trans_handle *trans, |
| struct extent_buffer *dst, |
| struct extent_buffer *src) |
| { |
| struct btrfs_fs_info *fs_info = trans->fs_info; |
| int push_items = 0; |
| int max_push; |
| int src_nritems; |
| int dst_nritems; |
| int ret = 0; |
| |
| WARN_ON(btrfs_header_generation(src) != trans->transid); |
| WARN_ON(btrfs_header_generation(dst) != trans->transid); |
| |
| src_nritems = btrfs_header_nritems(src); |
| dst_nritems = btrfs_header_nritems(dst); |
| push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems; |
| if (push_items <= 0) |
| return 1; |
| |
| if (src_nritems < 4) |
| return 1; |
| |
| max_push = src_nritems / 2 + 1; |
| /* don't try to empty the node */ |
| if (max_push >= src_nritems) |
| return 1; |
| |
| if (max_push < push_items) |
| push_items = max_push; |
| |
| /* dst is the right eb, src is the middle eb */ |
| if (check_sibling_keys(src, dst)) { |
| ret = -EUCLEAN; |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| |
| /* |
| * btrfs_tree_mod_log_eb_copy handles logging the move, so we don't |
| * need to do an explicit tree mod log operation for it. |
| */ |
| memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(dst, push_items), |
| btrfs_node_key_ptr_offset(dst, 0), |
| (dst_nritems) * |
| sizeof(struct btrfs_key_ptr)); |
| |
| ret = btrfs_tree_mod_log_eb_copy(dst, src, 0, src_nritems - push_items, |
| push_items); |
| if (ret) { |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| copy_extent_buffer(dst, src, |
| btrfs_node_key_ptr_offset(dst, 0), |
| btrfs_node_key_ptr_offset(src, src_nritems - push_items), |
| push_items * sizeof(struct btrfs_key_ptr)); |
| |
| btrfs_set_header_nritems(src, src_nritems - push_items); |
| btrfs_set_header_nritems(dst, dst_nritems + push_items); |
| |
| btrfs_mark_buffer_dirty(trans, src); |
| btrfs_mark_buffer_dirty(trans, dst); |
| |
| return ret; |
| } |
| |
| /* |
| * helper function to insert a new root level in the tree. |
| * A new node is allocated, and a single item is inserted to |
| * point to the existing root |
| * |
| * returns zero on success or < 0 on failure. |
| */ |
| static noinline int insert_new_root(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct btrfs_path *path, int level) |
| { |
| u64 lower_gen; |
| struct extent_buffer *lower; |
| struct extent_buffer *c; |
| struct extent_buffer *old; |
| struct btrfs_disk_key lower_key; |
| int ret; |
| |
| BUG_ON(path->nodes[level]); |
| BUG_ON(path->nodes[level-1] != root->node); |
| |
| lower = path->nodes[level-1]; |
| if (level == 1) |
| btrfs_item_key(lower, &lower_key, 0); |
| else |
| btrfs_node_key(lower, &lower_key, 0); |
| |
| c = btrfs_alloc_tree_block(trans, root, 0, btrfs_root_id(root), |
| &lower_key, level, root->node->start, 0, |
| 0, BTRFS_NESTING_NEW_ROOT); |
| if (IS_ERR(c)) |
| return PTR_ERR(c); |
| |
| root_add_used_bytes(root); |
| |
| btrfs_set_header_nritems(c, 1); |
| btrfs_set_node_key(c, &lower_key, 0); |
| btrfs_set_node_blockptr(c, 0, lower->start); |
| lower_gen = btrfs_header_generation(lower); |
| WARN_ON(lower_gen != trans->transid); |
| |
| btrfs_set_node_ptr_generation(c, 0, lower_gen); |
| |
| btrfs_mark_buffer_dirty(trans, c); |
| |
| old = root->node; |
| ret = btrfs_tree_mod_log_insert_root(root->node, c, false); |
| if (ret < 0) { |
| int ret2; |
| |
| ret2 = btrfs_free_tree_block(trans, btrfs_root_id(root), c, 0, 1); |
| if (ret2 < 0) |
| btrfs_abort_transaction(trans, ret2); |
| btrfs_tree_unlock(c); |
| free_extent_buffer(c); |
| return ret; |
| } |
| rcu_assign_pointer(root->node, c); |
| |
| /* the super has an extra ref to root->node */ |
| free_extent_buffer(old); |
| |
| add_root_to_dirty_list(root); |
| atomic_inc(&c->refs); |
| path->nodes[level] = c; |
| path->locks[level] = BTRFS_WRITE_LOCK; |
| path->slots[level] = 0; |
| return 0; |
| } |
| |
| /* |
| * worker function to insert a single pointer in a node. |
| * the node should have enough room for the pointer already |
| * |
| * slot and level indicate where you want the key to go, and |
| * blocknr is the block the key points to. |
| */ |
| static int insert_ptr(struct btrfs_trans_handle *trans, |
| struct btrfs_path *path, |
| struct btrfs_disk_key *key, u64 bytenr, |
| int slot, int level) |
| { |
| struct extent_buffer *lower; |
| int nritems; |
| int ret; |
| |
| BUG_ON(!path->nodes[level]); |
| btrfs_assert_tree_write_locked(path->nodes[level]); |
| lower = path->nodes[level]; |
| nritems = btrfs_header_nritems(lower); |
| BUG_ON(slot > nritems); |
| BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(trans->fs_info)); |
| if (slot != nritems) { |
| if (level) { |
| ret = btrfs_tree_mod_log_insert_move(lower, slot + 1, |
| slot, nritems - slot); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| } |
| memmove_extent_buffer(lower, |
| btrfs_node_key_ptr_offset(lower, slot + 1), |
| btrfs_node_key_ptr_offset(lower, slot), |
| (nritems - slot) * sizeof(struct btrfs_key_ptr)); |
| } |
| if (level) { |
| ret = btrfs_tree_mod_log_insert_key(lower, slot, |
| BTRFS_MOD_LOG_KEY_ADD); |
| if (ret < 0) { |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| } |
| btrfs_set_node_key(lower, key, slot); |
| btrfs_set_node_blockptr(lower, slot, bytenr); |
| WARN_ON(trans->transid == 0); |
| btrfs_set_node_ptr_generation(lower, slot, trans->transid); |
| btrfs_set_header_nritems(lower, nritems + 1); |
| btrfs_mark_buffer_dirty(trans, lower); |
| |
| return 0; |
| } |
| |
| /* |
| * split the node at the specified level in path in two. |
| * The path is corrected to point to the appropriate node after the split |
| * |
| * Before splitting this tries to make some room in the node by pushing |
| * left and right, if either one works, it returns right away. |
| * |
| * returns 0 on success and < 0 on failure |
| */ |
| static noinline int split_node(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, |
| struct btrfs_path *path, int level) |
| { |
| struct btrfs_fs_info *fs_info = root->fs_info; |
| struct extent_buffer *c; |
| struct extent_buffer *split; |
| struct btrfs_disk_key disk_key; |
| int mid; |
| int ret; |
| u32 c_nritems; |
| |
| c = path->nodes[level]; |
| WARN_ON(btrfs_header_generation(c) != trans->transid); |
| if (c == root->node) { |
| /* |
| * trying to split the root, lets make a new one |
| * |
| * tree mod log: We don't log_removal old root in |
| * insert_new_root, because that root buffer will be kept as a |
| * normal node. We are going to log removal of half of the |
| * elements below with btrfs_tree_mod_log_eb_copy(). We're |
| * holding a tree lock on the buffer, which is why we cannot |
| * race with other tree_mod_log users. |
| */ |
| ret = insert_new_root(trans, root, path, level + 1); |
| if (ret) |
| return ret; |
| } else { |
| ret = push_nodes_for_insert(trans, root, path, level); |
| c = path->nodes[level]; |
| if (!ret && btrfs_header_nritems(c) < |
| BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) |
| return 0; |
| if (ret < 0) |
| return ret; |
| } |
| |
| c_nritems = btrfs_header_nritems(c); |
| mid = (c_nritems + 1) / 2; |
| btrfs_node_key(c, &disk_key, mid); |
| |
| split = btrfs_alloc_tree_block(trans, root, 0, btrfs_root_id(root), |
| &disk_key, level, c->start, 0, |
| 0, BTRFS_NESTING_SPLIT); |
| if (IS_ERR(split)) |
| return PTR_ERR(split); |
| |
| root_add_used_bytes(root); |
| ASSERT(btrfs_header_level(c) == level); |
| |
| ret = btrfs_tree_mod_log_eb_copy(split, c, 0, mid, c_nritems - mid); |
| if (ret) { |
| btrfs_tree_unlock(split); |
| free_extent_buffer(split); |
| btrfs_abort_transaction(trans, ret); |
| return ret; |
| } |
| copy_extent_buffer(split, c, |
| btrfs_node_key_ptr_offset(split, 0), |
| btrfs_node_key_ptr_offset(c, mid), |
| (c_nritems - mid) * sizeof(struct btrfs_key_ptr)); |
| btrfs_set_header_nritems(split, c_nritems - mid); |
| btrfs_set_header_nritems(c, mid); |
| |
| btrfs_mark_buffer_dirty(trans, c); |
| btrfs_mark_buffer_dirty(trans, split); |
| |
| ret = insert_ptr(trans, path, &disk_key, split->start, |
| path->slots[level + 1] + 1, level + 1); |
| if (ret < 0) { |
| btrfs_tree_unlock(split); |
| free_extent_buffer(split); |
| return ret; |
| } |
| |
| if (path->slots[level] >= mid) { |
| path->slots[level] -= mid; |
| btrfs_tree_unlock(c); |
| free_extent_buffer(c); |
| path->nodes[level] = split; |
| path->slots[level + 1] += 1; |
| } else { |
| btrfs_tree_unlock(split); |
| free_extent_buffer(split); |
| } |
| return 0; |
| } |
| |
| /* |
| * how many bytes are required to store the items in a leaf. start |
| * and nr indicate which items in the leaf to check. This totals up the |
| * space used both by the item structs and the item data |
| */ |
| static int leaf_space_used(const struct extent_buffer *l, int start, int nr) |
| { |
| int data_len; |
| int nritems = btrfs_header_nritems(l); |
| int end = min(nritems, start + nr) - 1; |
| |
| if (!nr) |
| return 0; |
| data_len = btrfs_item_offset(l, start) + btrfs_item_size(l, start); |
| data_len = data_len - btrfs_item_offset(l, end); |
| data_len += sizeof(struct btrfs_item) * nr; |
| WARN_ON(data_len < 0); |
| return data_len; |
| } |
| |
| /* |
| * The space between the end of the leaf items and |
| * the start of the leaf data. IOW, how much room |
| * the leaf has left for both items and data |
| */ |
| int btrfs_leaf_free_space(const struct extent_buffer *leaf) |
| { |
| struct btrfs_fs_info *fs_info = leaf->fs_info; |
| int nritems = btrfs_header_nritems(leaf); |
| int ret; |
| |
| ret = BTRFS_LEAF_DATA_SIZE(fs_info) - leaf_space_used(leaf, 0, nritems); |
| if (ret < 0) { |
| btrfs_crit(fs_info, |
| "leaf free space ret %d, leaf data size %lu, used %d nritems %d", |
| ret, |
| (unsigned long) BTRFS_LEAF_DATA_SIZE(fs_info), |
| leaf_space_used(leaf, 0, |