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4611 lines
119 KiB
4611 lines
119 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2007,2008 Oracle. All rights reserved. |
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*/ |
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|
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#include <linux/sched.h> |
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#include <linux/slab.h> |
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#include <linux/rbtree.h> |
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#include <linux/mm.h> |
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#include "ctree.h" |
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#include "disk-io.h" |
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#include "transaction.h" |
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#include "print-tree.h" |
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#include "locking.h" |
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#include "volumes.h" |
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#include "qgroup.h" |
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#include "tree-mod-log.h" |
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|
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static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root |
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*root, struct btrfs_path *path, int level); |
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static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
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const struct btrfs_key *ins_key, struct btrfs_path *path, |
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int data_size, int extend); |
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static int push_node_left(struct btrfs_trans_handle *trans, |
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struct extent_buffer *dst, |
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struct extent_buffer *src, int empty); |
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static int balance_node_right(struct btrfs_trans_handle *trans, |
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struct extent_buffer *dst_buf, |
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struct extent_buffer *src_buf); |
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static void del_ptr(struct btrfs_root *root, struct btrfs_path *path, |
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int level, int slot); |
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|
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static const struct btrfs_csums { |
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u16 size; |
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const char name[10]; |
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const char driver[12]; |
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} btrfs_csums[] = { |
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[BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" }, |
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[BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" }, |
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[BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" }, |
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[BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b", |
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.driver = "blake2b-256" }, |
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}; |
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|
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int btrfs_super_csum_size(const struct btrfs_super_block *s) |
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{ |
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u16 t = btrfs_super_csum_type(s); |
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/* |
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* csum type is validated at mount time |
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*/ |
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return btrfs_csums[t].size; |
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} |
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|
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const char *btrfs_super_csum_name(u16 csum_type) |
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{ |
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/* csum type is validated at mount time */ |
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return btrfs_csums[csum_type].name; |
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} |
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|
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/* |
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* Return driver name if defined, otherwise the name that's also a valid driver |
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* name |
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*/ |
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const char *btrfs_super_csum_driver(u16 csum_type) |
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{ |
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/* csum type is validated at mount time */ |
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return btrfs_csums[csum_type].driver[0] ? |
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btrfs_csums[csum_type].driver : |
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btrfs_csums[csum_type].name; |
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} |
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|
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size_t __attribute_const__ btrfs_get_num_csums(void) |
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{ |
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return ARRAY_SIZE(btrfs_csums); |
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} |
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|
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struct btrfs_path *btrfs_alloc_path(void) |
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{ |
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return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS); |
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} |
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|
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/* this also releases the path */ |
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void btrfs_free_path(struct btrfs_path *p) |
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{ |
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if (!p) |
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return; |
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btrfs_release_path(p); |
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kmem_cache_free(btrfs_path_cachep, p); |
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} |
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|
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/* |
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* path release drops references on the extent buffers in the path |
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* and it drops any locks held by this path |
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* |
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* It is safe to call this on paths that no locks or extent buffers held. |
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*/ |
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noinline void btrfs_release_path(struct btrfs_path *p) |
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{ |
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int i; |
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|
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for (i = 0; i < BTRFS_MAX_LEVEL; i++) { |
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p->slots[i] = 0; |
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if (!p->nodes[i]) |
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continue; |
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if (p->locks[i]) { |
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btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]); |
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p->locks[i] = 0; |
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} |
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free_extent_buffer(p->nodes[i]); |
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p->nodes[i] = NULL; |
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} |
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} |
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|
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/* |
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* safely gets a reference on the root node of a tree. A lock |
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* is not taken, so a concurrent writer may put a different node |
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* at the root of the tree. See btrfs_lock_root_node for the |
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* looping required. |
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* |
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* The extent buffer returned by this has a reference taken, so |
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* it won't disappear. It may stop being the root of the tree |
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* at any time because there are no locks held. |
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*/ |
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struct extent_buffer *btrfs_root_node(struct btrfs_root *root) |
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{ |
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struct extent_buffer *eb; |
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|
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while (1) { |
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rcu_read_lock(); |
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eb = rcu_dereference(root->node); |
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|
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/* |
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* RCU really hurts here, we could free up the root node because |
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* it was COWed but we may not get the new root node yet so do |
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* the inc_not_zero dance and if it doesn't work then |
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* synchronize_rcu and try again. |
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*/ |
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if (atomic_inc_not_zero(&eb->refs)) { |
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rcu_read_unlock(); |
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break; |
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} |
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rcu_read_unlock(); |
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synchronize_rcu(); |
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} |
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return eb; |
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} |
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/* |
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* Cowonly root (not-shareable trees, everything not subvolume or reloc roots), |
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* just get put onto a simple dirty list. Transaction walks this list to make |
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* sure they get properly updated on disk. |
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*/ |
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static void add_root_to_dirty_list(struct btrfs_root *root) |
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{ |
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struct btrfs_fs_info *fs_info = root->fs_info; |
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|
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if (test_bit(BTRFS_ROOT_DIRTY, &root->state) || |
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!test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state)) |
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return; |
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|
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spin_lock(&fs_info->trans_lock); |
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if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) { |
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/* Want the extent tree to be the last on the list */ |
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if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID) |
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list_move_tail(&root->dirty_list, |
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&fs_info->dirty_cowonly_roots); |
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else |
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list_move(&root->dirty_list, |
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&fs_info->dirty_cowonly_roots); |
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} |
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spin_unlock(&fs_info->trans_lock); |
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} |
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/* |
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* used by snapshot creation to make a copy of a root for a tree with |
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* a given objectid. The buffer with the new root node is returned in |
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* cow_ret, and this func returns zero on success or a negative error code. |
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*/ |
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int btrfs_copy_root(struct btrfs_trans_handle *trans, |
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struct btrfs_root *root, |
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struct extent_buffer *buf, |
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struct extent_buffer **cow_ret, u64 new_root_objectid) |
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{ |
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struct btrfs_fs_info *fs_info = root->fs_info; |
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struct extent_buffer *cow; |
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int ret = 0; |
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int level; |
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struct btrfs_disk_key disk_key; |
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WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
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trans->transid != fs_info->running_transaction->transid); |
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WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
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trans->transid != root->last_trans); |
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level = btrfs_header_level(buf); |
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if (level == 0) |
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btrfs_item_key(buf, &disk_key, 0); |
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else |
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btrfs_node_key(buf, &disk_key, 0); |
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cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid, |
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&disk_key, level, buf->start, 0, |
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BTRFS_NESTING_NEW_ROOT); |
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if (IS_ERR(cow)) |
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return PTR_ERR(cow); |
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copy_extent_buffer_full(cow, buf); |
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btrfs_set_header_bytenr(cow, cow->start); |
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btrfs_set_header_generation(cow, trans->transid); |
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btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
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btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
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BTRFS_HEADER_FLAG_RELOC); |
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if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
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btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
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else |
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btrfs_set_header_owner(cow, new_root_objectid); |
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write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid); |
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WARN_ON(btrfs_header_generation(buf) > trans->transid); |
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if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID) |
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ret = btrfs_inc_ref(trans, root, cow, 1); |
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else |
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ret = btrfs_inc_ref(trans, root, cow, 0); |
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if (ret) { |
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btrfs_tree_unlock(cow); |
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free_extent_buffer(cow); |
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btrfs_abort_transaction(trans, ret); |
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return ret; |
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} |
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btrfs_mark_buffer_dirty(cow); |
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*cow_ret = cow; |
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return 0; |
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} |
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/* |
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* check if the tree block can be shared by multiple trees |
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*/ |
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int btrfs_block_can_be_shared(struct btrfs_root *root, |
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struct extent_buffer *buf) |
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{ |
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/* |
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* Tree blocks not in shareable trees and tree roots are never shared. |
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* If a block was allocated after the last snapshot and the block was |
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* not allocated by tree relocation, we know the block is not shared. |
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*/ |
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if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
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buf != root->node && buf != root->commit_root && |
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(btrfs_header_generation(buf) <= |
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btrfs_root_last_snapshot(&root->root_item) || |
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btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC))) |
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return 1; |
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return 0; |
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} |
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static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans, |
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struct btrfs_root *root, |
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struct extent_buffer *buf, |
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struct extent_buffer *cow, |
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int *last_ref) |
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{ |
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struct btrfs_fs_info *fs_info = root->fs_info; |
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u64 refs; |
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u64 owner; |
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u64 flags; |
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u64 new_flags = 0; |
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int ret; |
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/* |
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* Backrefs update rules: |
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* |
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* Always use full backrefs for extent pointers in tree block |
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* allocated by tree relocation. |
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* |
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* If a shared tree block is no longer referenced by its owner |
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* tree (btrfs_header_owner(buf) == root->root_key.objectid), |
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* use full backrefs for extent pointers in tree block. |
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* |
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* If a tree block is been relocating |
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* (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID), |
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* use full backrefs for extent pointers in tree block. |
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* The reason for this is some operations (such as drop tree) |
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* are only allowed for blocks use full backrefs. |
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*/ |
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if (btrfs_block_can_be_shared(root, buf)) { |
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ret = btrfs_lookup_extent_info(trans, fs_info, buf->start, |
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btrfs_header_level(buf), 1, |
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&refs, &flags); |
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if (ret) |
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return ret; |
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if (refs == 0) { |
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ret = -EROFS; |
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btrfs_handle_fs_error(fs_info, ret, NULL); |
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return ret; |
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} |
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} else { |
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refs = 1; |
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if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
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btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
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flags = BTRFS_BLOCK_FLAG_FULL_BACKREF; |
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else |
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flags = 0; |
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} |
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|
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owner = btrfs_header_owner(buf); |
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BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID && |
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!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)); |
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|
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if (refs > 1) { |
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if ((owner == root->root_key.objectid || |
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root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && |
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!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) { |
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ret = btrfs_inc_ref(trans, root, buf, 1); |
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if (ret) |
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return ret; |
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|
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if (root->root_key.objectid == |
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BTRFS_TREE_RELOC_OBJECTID) { |
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ret = btrfs_dec_ref(trans, root, buf, 0); |
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if (ret) |
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return ret; |
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ret = btrfs_inc_ref(trans, root, cow, 1); |
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if (ret) |
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return ret; |
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} |
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new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF; |
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} else { |
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|
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if (root->root_key.objectid == |
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BTRFS_TREE_RELOC_OBJECTID) |
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ret = btrfs_inc_ref(trans, root, cow, 1); |
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else |
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ret = btrfs_inc_ref(trans, root, cow, 0); |
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if (ret) |
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return ret; |
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} |
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if (new_flags != 0) { |
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int level = btrfs_header_level(buf); |
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|
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ret = btrfs_set_disk_extent_flags(trans, buf, |
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new_flags, level, 0); |
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if (ret) |
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return ret; |
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} |
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} else { |
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if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) { |
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if (root->root_key.objectid == |
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BTRFS_TREE_RELOC_OBJECTID) |
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ret = btrfs_inc_ref(trans, root, cow, 1); |
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else |
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ret = btrfs_inc_ref(trans, root, cow, 0); |
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if (ret) |
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return ret; |
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ret = btrfs_dec_ref(trans, root, buf, 1); |
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if (ret) |
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return ret; |
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} |
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btrfs_clean_tree_block(buf); |
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*last_ref = 1; |
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} |
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return 0; |
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} |
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|
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/* |
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* does the dirty work in cow of a single block. The parent block (if |
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* supplied) is updated to point to the new cow copy. The new buffer is marked |
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* dirty and returned locked. If you modify the block it needs to be marked |
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* dirty again. |
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* |
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* search_start -- an allocation hint for the new block |
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* |
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* empty_size -- a hint that you plan on doing more cow. This is the size in |
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* bytes the allocator should try to find free next to the block it returns. |
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* This is just a hint and may be ignored by the allocator. |
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*/ |
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static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans, |
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struct btrfs_root *root, |
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struct extent_buffer *buf, |
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struct extent_buffer *parent, int parent_slot, |
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struct extent_buffer **cow_ret, |
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u64 search_start, u64 empty_size, |
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enum btrfs_lock_nesting nest) |
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{ |
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struct btrfs_fs_info *fs_info = root->fs_info; |
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struct btrfs_disk_key disk_key; |
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struct extent_buffer *cow; |
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int level, ret; |
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int last_ref = 0; |
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int unlock_orig = 0; |
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u64 parent_start = 0; |
|
|
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if (*cow_ret == buf) |
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unlock_orig = 1; |
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|
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btrfs_assert_tree_locked(buf); |
|
|
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WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
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trans->transid != fs_info->running_transaction->transid); |
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WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && |
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trans->transid != root->last_trans); |
|
|
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level = btrfs_header_level(buf); |
|
|
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if (level == 0) |
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btrfs_item_key(buf, &disk_key, 0); |
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else |
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btrfs_node_key(buf, &disk_key, 0); |
|
|
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if ((root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && parent) |
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parent_start = parent->start; |
|
|
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cow = btrfs_alloc_tree_block(trans, root, parent_start, |
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root->root_key.objectid, &disk_key, level, |
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search_start, empty_size, nest); |
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if (IS_ERR(cow)) |
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return PTR_ERR(cow); |
|
|
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/* cow is set to blocking by btrfs_init_new_buffer */ |
|
|
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copy_extent_buffer_full(cow, buf); |
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btrfs_set_header_bytenr(cow, cow->start); |
|
btrfs_set_header_generation(cow, trans->transid); |
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btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV); |
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btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN | |
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BTRFS_HEADER_FLAG_RELOC); |
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if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) |
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btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC); |
|
else |
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btrfs_set_header_owner(cow, root->root_key.objectid); |
|
|
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write_extent_buffer_fsid(cow, fs_info->fs_devices->metadata_uuid); |
|
|
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ret = update_ref_for_cow(trans, root, buf, cow, &last_ref); |
|
if (ret) { |
|
btrfs_tree_unlock(cow); |
|
free_extent_buffer(cow); |
|
btrfs_abort_transaction(trans, ret); |
|
return ret; |
|
} |
|
|
|
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) { |
|
ret = btrfs_reloc_cow_block(trans, root, buf, cow); |
|
if (ret) { |
|
btrfs_tree_unlock(cow); |
|
free_extent_buffer(cow); |
|
btrfs_abort_transaction(trans, ret); |
|
return ret; |
|
} |
|
} |
|
|
|
if (buf == root->node) { |
|
WARN_ON(parent && parent != buf); |
|
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID || |
|
btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV) |
|
parent_start = buf->start; |
|
|
|
atomic_inc(&cow->refs); |
|
ret = btrfs_tree_mod_log_insert_root(root->node, cow, true); |
|
BUG_ON(ret < 0); |
|
rcu_assign_pointer(root->node, cow); |
|
|
|
btrfs_free_tree_block(trans, root, buf, parent_start, |
|
last_ref); |
|
free_extent_buffer(buf); |
|
add_root_to_dirty_list(root); |
|
} else { |
|
WARN_ON(trans->transid != btrfs_header_generation(parent)); |
|
btrfs_tree_mod_log_insert_key(parent, parent_slot, |
|
BTRFS_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 = btrfs_tree_mod_log_free_eb(buf); |
|
if (ret) { |
|
btrfs_tree_unlock(cow); |
|
free_extent_buffer(cow); |
|
btrfs_abort_transaction(trans, ret); |
|
return ret; |
|
} |
|
} |
|
btrfs_free_tree_block(trans, 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; |
|
} |
|
|
|
static inline int should_cow_block(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct extent_buffer *buf) |
|
{ |
|
if (btrfs_is_testing(root->fs_info)) |
|
return 0; |
|
|
|
/* Ensure we can see the FORCE_COW bit */ |
|
smp_mb__before_atomic(); |
|
|
|
/* |
|
* We do not need to cow a block if |
|
* 1) this block is not created or changed in this transaction; |
|
* 2) this block does not belong to TREE_RELOC tree; |
|
* 3) the root is not forced COW. |
|
* |
|
* What is forced COW: |
|
* when we create snapshot during committing the transaction, |
|
* after we've finished copying src root, we must COW the shared |
|
* block to ensure the metadata consistency. |
|
*/ |
|
if (btrfs_header_generation(buf) == trans->transid && |
|
!btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) && |
|
!(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID && |
|
btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) && |
|
!test_bit(BTRFS_ROOT_FORCE_COW, &root->state)) |
|
return 0; |
|
return 1; |
|
} |
|
|
|
/* |
|
* cows a single block, see __btrfs_cow_block for the real work. |
|
* This version of it has extra checks so that a block isn't COWed more than |
|
* once per transaction, as long as it hasn't been written yet |
|
*/ |
|
noinline int btrfs_cow_block(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, struct extent_buffer *buf, |
|
struct extent_buffer *parent, int parent_slot, |
|
struct extent_buffer **cow_ret, |
|
enum btrfs_lock_nesting nest) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
u64 search_start; |
|
int ret; |
|
|
|
if (test_bit(BTRFS_ROOT_DELETING, &root->state)) |
|
btrfs_err(fs_info, |
|
"COW'ing blocks on a fs root that's being dropped"); |
|
|
|
if (trans->transaction != fs_info->running_transaction) |
|
WARN(1, KERN_CRIT "trans %llu running %llu\n", |
|
trans->transid, |
|
fs_info->running_transaction->transid); |
|
|
|
if (trans->transid != fs_info->generation) |
|
WARN(1, KERN_CRIT "trans %llu running %llu\n", |
|
trans->transid, fs_info->generation); |
|
|
|
if (!should_cow_block(trans, root, buf)) { |
|
*cow_ret = buf; |
|
return 0; |
|
} |
|
|
|
search_start = buf->start & ~((u64)SZ_1G - 1); |
|
|
|
/* |
|
* Before CoWing this block for later modification, check if it's |
|
* the subtree root and do the delayed subtree trace if needed. |
|
* |
|
* Also We don't care about the error, as it's handled internally. |
|
*/ |
|
btrfs_qgroup_trace_subtree_after_cow(trans, root, buf); |
|
ret = __btrfs_cow_block(trans, root, buf, parent, |
|
parent_slot, cow_ret, search_start, 0, nest); |
|
|
|
trace_btrfs_cow_block(root, buf, *cow_ret); |
|
|
|
return ret; |
|
} |
|
ALLOW_ERROR_INJECTION(btrfs_cow_block, ERRNO); |
|
|
|
/* |
|
* 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; |
|
} |
|
|
|
#ifdef __LITTLE_ENDIAN |
|
|
|
/* |
|
* Compare two keys, on little-endian the disk order is same as CPU order and |
|
* we can avoid the conversion. |
|
*/ |
|
static int comp_keys(const struct btrfs_disk_key *disk_key, |
|
const struct btrfs_key *k2) |
|
{ |
|
const struct btrfs_key *k1 = (const struct btrfs_key *)disk_key; |
|
|
|
return btrfs_comp_cpu_keys(k1, k2); |
|
} |
|
|
|
#else |
|
|
|
/* |
|
* compare two keys in a memcmp fashion |
|
*/ |
|
static int comp_keys(const struct btrfs_disk_key *disk, |
|
const struct btrfs_key *k2) |
|
{ |
|
struct btrfs_key k1; |
|
|
|
btrfs_disk_key_to_cpu(&k1, disk); |
|
|
|
return btrfs_comp_cpu_keys(&k1, k2); |
|
} |
|
#endif |
|
|
|
/* |
|
* same as comp_keys only with two btrfs_key's |
|
*/ |
|
int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2) |
|
{ |
|
if (k1->objectid > k2->objectid) |
|
return 1; |
|
if (k1->objectid < k2->objectid) |
|
return -1; |
|
if (k1->type > k2->type) |
|
return 1; |
|
if (k1->type < k2->type) |
|
return -1; |
|
if (k1->offset > k2->offset) |
|
return 1; |
|
if (k1->offset < k2->offset) |
|
return -1; |
|
return 0; |
|
} |
|
|
|
/* |
|
* this is used by the defrag code to go through all the |
|
* leaves pointed to by a node and reallocate them so that |
|
* disk order is close to key order |
|
*/ |
|
int btrfs_realloc_node(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, struct extent_buffer *parent, |
|
int start_slot, u64 *last_ret, |
|
struct btrfs_key *progress) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
struct extent_buffer *cur; |
|
u64 blocknr; |
|
u64 search_start = *last_ret; |
|
u64 last_block = 0; |
|
u64 other; |
|
u32 parent_nritems; |
|
int end_slot; |
|
int i; |
|
int err = 0; |
|
u32 blocksize; |
|
int progress_passed = 0; |
|
struct btrfs_disk_key disk_key; |
|
|
|
WARN_ON(trans->transaction != fs_info->running_transaction); |
|
WARN_ON(trans->transid != fs_info->generation); |
|
|
|
parent_nritems = btrfs_header_nritems(parent); |
|
blocksize = fs_info->nodesize; |
|
end_slot = parent_nritems - 1; |
|
|
|
if (parent_nritems <= 1) |
|
return 0; |
|
|
|
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); |
|
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_read_node_slot(parent, i); |
|
if (IS_ERR(cur)) |
|
return PTR_ERR(cur); |
|
if (search_start == 0) |
|
search_start = last_block; |
|
|
|
btrfs_tree_lock(cur); |
|
err = __btrfs_cow_block(trans, root, cur, parent, i, |
|
&cur, search_start, |
|
min(16 * blocksize, |
|
(end_slot - i) * blocksize), |
|
BTRFS_NESTING_COW); |
|
if (err) { |
|
btrfs_tree_unlock(cur); |
|
free_extent_buffer(cur); |
|
break; |
|
} |
|
search_start = cur->start; |
|
last_block = cur->start; |
|
*last_ret = search_start; |
|
btrfs_tree_unlock(cur); |
|
free_extent_buffer(cur); |
|
} |
|
return err; |
|
} |
|
|
|
/* |
|
* search for key in the extent_buffer. The items start at offset p, |
|
* and they are item_size apart. There are 'max' items in p. |
|
* |
|
* the slot in the array is returned via slot, and it points to |
|
* the place where you would insert key if it is not found in |
|
* the array. |
|
* |
|
* slot may point to max if the key is bigger than all of the keys |
|
*/ |
|
static noinline int generic_bin_search(struct extent_buffer *eb, |
|
unsigned long p, int item_size, |
|
const struct btrfs_key *key, |
|
int max, int *slot) |
|
{ |
|
int low = 0; |
|
int high = max; |
|
int ret; |
|
const int key_size = sizeof(struct btrfs_disk_key); |
|
|
|
if (low > high) { |
|
btrfs_err(eb->fs_info, |
|
"%s: low (%d) > high (%d) eb %llu owner %llu level %d", |
|
__func__, low, high, eb->start, |
|
btrfs_header_owner(eb), btrfs_header_level(eb)); |
|
return -EINVAL; |
|
} |
|
|
|
while (low < high) { |
|
unsigned long oip; |
|
unsigned long offset; |
|
struct btrfs_disk_key *tmp; |
|
struct btrfs_disk_key unaligned; |
|
int mid; |
|
|
|
mid = (low + high) / 2; |
|
offset = p + mid * item_size; |
|
oip = offset_in_page(offset); |
|
|
|
if (oip + key_size <= PAGE_SIZE) { |
|
const unsigned long idx = get_eb_page_index(offset); |
|
char *kaddr = page_address(eb->pages[idx]); |
|
|
|
oip = get_eb_offset_in_page(eb, offset); |
|
tmp = (struct btrfs_disk_key *)(kaddr + oip); |
|
} else { |
|
read_extent_buffer(eb, &unaligned, offset, key_size); |
|
tmp = &unaligned; |
|
} |
|
|
|
ret = comp_keys(tmp, key); |
|
|
|
if (ret < 0) |
|
low = mid + 1; |
|
else if (ret > 0) |
|
high = mid; |
|
else { |
|
*slot = mid; |
|
return 0; |
|
} |
|
} |
|
*slot = low; |
|
return 1; |
|
} |
|
|
|
/* |
|
* simple bin_search frontend that does the right thing for |
|
* leaves vs nodes |
|
*/ |
|
int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key, |
|
int *slot) |
|
{ |
|
if (btrfs_header_level(eb) == 0) |
|
return generic_bin_search(eb, |
|
offsetof(struct btrfs_leaf, items), |
|
sizeof(struct btrfs_item), |
|
key, btrfs_header_nritems(eb), |
|
slot); |
|
else |
|
return generic_bin_search(eb, |
|
offsetof(struct btrfs_node, ptrs), |
|
sizeof(struct btrfs_key_ptr), |
|
key, btrfs_header_nritems(eb), |
|
slot); |
|
} |
|
|
|
static void root_add_used(struct btrfs_root *root, u32 size) |
|
{ |
|
spin_lock(&root->accounting_lock); |
|
btrfs_set_root_used(&root->root_item, |
|
btrfs_root_used(&root->root_item) + size); |
|
spin_unlock(&root->accounting_lock); |
|
} |
|
|
|
static void root_sub_used(struct btrfs_root *root, u32 size) |
|
{ |
|
spin_lock(&root->accounting_lock); |
|
btrfs_set_root_used(&root->root_item, |
|
btrfs_root_used(&root->root_item) - size); |
|
spin_unlock(&root->accounting_lock); |
|
} |
|
|
|
/* given a node and slot number, this reads the blocks it points to. The |
|
* extent buffer is returned with a reference taken (but unlocked). |
|
*/ |
|
struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent, |
|
int slot) |
|
{ |
|
int level = btrfs_header_level(parent); |
|
struct extent_buffer *eb; |
|
struct btrfs_key first_key; |
|
|
|
if (slot < 0 || slot >= btrfs_header_nritems(parent)) |
|
return ERR_PTR(-ENOENT); |
|
|
|
BUG_ON(level == 0); |
|
|
|
btrfs_node_key_to_cpu(parent, &first_key, slot); |
|
eb = read_tree_block(parent->fs_info, btrfs_node_blockptr(parent, slot), |
|
btrfs_header_owner(parent), |
|
btrfs_node_ptr_generation(parent, slot), |
|
level - 1, &first_key); |
|
if (!IS_ERR(eb) && !extent_buffer_uptodate(eb)) { |
|
free_extent_buffer(eb); |
|
eb = ERR_PTR(-EIO); |
|
} |
|
|
|
return eb; |
|
} |
|
|
|
/* |
|
* node level balancing, used to make sure nodes are in proper order for |
|
* item deletion. We balance from the top down, so we have to make sure |
|
* that a deletion won't leave an node completely empty later on. |
|
*/ |
|
static noinline int balance_level(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, int level) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
struct extent_buffer *right = NULL; |
|
struct extent_buffer *mid; |
|
struct extent_buffer *left = NULL; |
|
struct extent_buffer *parent = NULL; |
|
int ret = 0; |
|
int wret; |
|
int pslot; |
|
int orig_slot = path->slots[level]; |
|
u64 orig_ptr; |
|
|
|
ASSERT(level > 0); |
|
|
|
mid = path->nodes[level]; |
|
|
|
WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK); |
|
WARN_ON(btrfs_header_generation(mid) != trans->transid); |
|
|
|
orig_ptr = btrfs_node_blockptr(mid, orig_slot); |
|
|
|
if (level < BTRFS_MAX_LEVEL - 1) { |
|
parent = path->nodes[level + 1]; |
|
pslot = path->slots[level + 1]; |
|
} |
|
|
|
/* |
|
* deal with the case where there is only one pointer in the root |
|
* by promoting the node below to a root |
|
*/ |
|
if (!parent) { |
|
struct extent_buffer *child; |
|
|
|
if (btrfs_header_nritems(mid) != 1) |
|
return 0; |
|
|
|
/* promote the child to a root */ |
|
child = btrfs_read_node_slot(mid, 0); |
|
if (IS_ERR(child)) { |
|
ret = PTR_ERR(child); |
|
btrfs_handle_fs_error(fs_info, ret, NULL); |
|
goto enospc; |
|
} |
|
|
|
btrfs_tree_lock(child); |
|
ret = btrfs_cow_block(trans, root, child, mid, 0, &child, |
|
BTRFS_NESTING_COW); |
|
if (ret) { |
|
btrfs_tree_unlock(child); |
|
free_extent_buffer(child); |
|
goto enospc; |
|
} |
|
|
|
ret = btrfs_tree_mod_log_insert_root(root->node, child, true); |
|
BUG_ON(ret < 0); |
|
rcu_assign_pointer(root->node, child); |
|
|
|
add_root_to_dirty_list(root); |
|
btrfs_tree_unlock(child); |
|
|
|
path->locks[level] = 0; |
|
path->nodes[level] = NULL; |
|
btrfs_clean_tree_block(mid); |
|
btrfs_tree_unlock(mid); |
|
/* once for the path */ |
|
free_extent_buffer(mid); |
|
|
|
root_sub_used(root, mid->len); |
|
btrfs_free_tree_block(trans, root, mid, 0, 1); |
|
/* once for the root ptr */ |
|
free_extent_buffer_stale(mid); |
|
return 0; |
|
} |
|
if (btrfs_header_nritems(mid) > |
|
BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4) |
|
return 0; |
|
|
|
left = btrfs_read_node_slot(parent, pslot - 1); |
|
if (IS_ERR(left)) |
|
left = NULL; |
|
|
|
if (left) { |
|
__btrfs_tree_lock(left, BTRFS_NESTING_LEFT); |
|
wret = btrfs_cow_block(trans, root, left, |
|
parent, pslot - 1, &left, |
|
BTRFS_NESTING_LEFT_COW); |
|
if (wret) { |
|
ret = wret; |
|
goto enospc; |
|
} |
|
} |
|
|
|
right = btrfs_read_node_slot(parent, pslot + 1); |
|
if (IS_ERR(right)) |
|
right = NULL; |
|
|
|
if (right) { |
|
__btrfs_tree_lock(right, BTRFS_NESTING_RIGHT); |
|
wret = btrfs_cow_block(trans, root, right, |
|
parent, pslot + 1, &right, |
|
BTRFS_NESTING_RIGHT_COW); |
|
if (wret) { |
|
ret = wret; |
|
goto enospc; |
|
} |
|
} |
|
|
|
/* first, try to make some room in the middle buffer */ |
|
if (left) { |
|
orig_slot += btrfs_header_nritems(left); |
|
wret = push_node_left(trans, left, mid, 1); |
|
if (wret < 0) |
|
ret = wret; |
|
} |
|
|
|
/* |
|
* then try to empty the right most buffer into the middle |
|
*/ |
|
if (right) { |
|
wret = push_node_left(trans, mid, right, 1); |
|
if (wret < 0 && wret != -ENOSPC) |
|
ret = wret; |
|
if (btrfs_header_nritems(right) == 0) { |
|
btrfs_clean_tree_block(right); |
|
btrfs_tree_unlock(right); |
|
del_ptr(root, path, level + 1, pslot + 1); |
|
root_sub_used(root, right->len); |
|
btrfs_free_tree_block(trans, root, right, 0, 1); |
|
free_extent_buffer_stale(right); |
|
right = NULL; |
|
} else { |
|
struct btrfs_disk_key right_key; |
|
btrfs_node_key(right, &right_key, 0); |
|
ret = btrfs_tree_mod_log_insert_key(parent, pslot + 1, |
|
BTRFS_MOD_LOG_KEY_REPLACE, GFP_NOFS); |
|
BUG_ON(ret < 0); |
|
btrfs_set_node_key(parent, &right_key, pslot + 1); |
|
btrfs_mark_buffer_dirty(parent); |
|
} |
|
} |
|
if (btrfs_header_nritems(mid) == 1) { |
|
/* |
|
* we're not allowed to leave a node with one item in the |
|
* tree during a delete. A deletion from lower in the tree |
|
* could try to delete the only pointer in this node. |
|
* So, pull some keys from the left. |
|
* There has to be a left pointer at this point because |
|
* otherwise we would have pulled some pointers from the |
|
* right |
|
*/ |
|
if (!left) { |
|
ret = -EROFS; |
|
btrfs_handle_fs_error(fs_info, ret, NULL); |
|
goto enospc; |
|
} |
|
wret = balance_node_right(trans, mid, left); |
|
if (wret < 0) { |
|
ret = wret; |
|
goto enospc; |
|
} |
|
if (wret == 1) { |
|
wret = push_node_left(trans, left, mid, 1); |
|
if (wret < 0) |
|
ret = wret; |
|
} |
|
BUG_ON(wret == 1); |
|
} |
|
if (btrfs_header_nritems(mid) == 0) { |
|
btrfs_clean_tree_block(mid); |
|
btrfs_tree_unlock(mid); |
|
del_ptr(root, path, level + 1, pslot); |
|
root_sub_used(root, mid->len); |
|
btrfs_free_tree_block(trans, root, mid, 0, 1); |
|
free_extent_buffer_stale(mid); |
|
mid = NULL; |
|
} else { |
|
/* update the parent key to reflect our changes */ |
|
struct btrfs_disk_key mid_key; |
|
btrfs_node_key(mid, &mid_key, 0); |
|
ret = btrfs_tree_mod_log_insert_key(parent, pslot, |
|
BTRFS_MOD_LOG_KEY_REPLACE, GFP_NOFS); |
|
BUG_ON(ret < 0); |
|
btrfs_set_node_key(parent, &mid_key, pslot); |
|
btrfs_mark_buffer_dirty(parent); |
|
} |
|
|
|
/* update the path */ |
|
if (left) { |
|
if (btrfs_header_nritems(left) > orig_slot) { |
|
atomic_inc(&left->refs); |
|
/* left was locked after cow */ |
|
path->nodes[level] = left; |
|
path->slots[level + 1] -= 1; |
|
path->slots[level] = orig_slot; |
|
if (mid) { |
|
btrfs_tree_unlock(mid); |
|
free_extent_buffer(mid); |
|
} |
|
} else { |
|
orig_slot -= btrfs_header_nritems(left); |
|
path->slots[level] = orig_slot; |
|
} |
|
} |
|
/* double check we haven't messed things up */ |
|
if (orig_ptr != |
|
btrfs_node_blockptr(path->nodes[level], path->slots[level])) |
|
BUG(); |
|
enospc: |
|
if (right) { |
|
btrfs_tree_unlock(right); |
|
free_extent_buffer(right); |
|
} |
|
if (left) { |
|
if (path->nodes[level] != left) |
|
btrfs_tree_unlock(left); |
|
free_extent_buffer(left); |
|
} |
|
return ret; |
|
} |
|
|
|
/* Node balancing for insertion. Here we only split or push nodes around |
|
* when they are completely full. This is also done top down, so we |
|
* have to be pessimistic. |
|
*/ |
|
static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, int level) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
struct extent_buffer *right = NULL; |
|
struct extent_buffer *mid; |
|
struct extent_buffer *left = NULL; |
|
struct extent_buffer *parent = NULL; |
|
int ret = 0; |
|
int wret; |
|
int pslot; |
|
int orig_slot = path->slots[level]; |
|
|
|
if (level == 0) |
|
return 1; |
|
|
|
mid = path->nodes[level]; |
|
WARN_ON(btrfs_header_generation(mid) != trans->transid); |
|
|
|
if (level < BTRFS_MAX_LEVEL - 1) { |
|
parent = path->nodes[level + 1]; |
|
pslot = path->slots[level + 1]; |
|
} |
|
|
|
if (!parent) |
|
return 1; |
|
|
|
left = btrfs_read_node_slot(parent, pslot - 1); |
|
if (IS_ERR(left)) |
|
left = NULL; |
|
|
|
/* first, try to make some room in the middle buffer */ |
|
if (left) { |
|
u32 left_nr; |
|
|
|
__btrfs_tree_lock(left, BTRFS_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, GFP_NOFS); |
|
BUG_ON(ret < 0); |
|
btrfs_set_node_key(parent, &disk_key, pslot); |
|
btrfs_mark_buffer_dirty(parent); |
|
if (btrfs_header_nritems(left) > orig_slot) { |
|
path->nodes[level] = left; |
|
path->slots[level + 1] -= 1; |
|
path->slots[level] = orig_slot; |
|
btrfs_tree_unlock(mid); |
|
free_extent_buffer(mid); |
|
} else { |
|
orig_slot -= |
|
btrfs_header_nritems(left); |
|
path->slots[level] = orig_slot; |
|
btrfs_tree_unlock(left); |
|
free_extent_buffer(left); |
|
} |
|
return 0; |
|
} |
|
btrfs_tree_unlock(left); |
|
free_extent_buffer(left); |
|
} |
|
right = btrfs_read_node_slot(parent, pslot + 1); |
|
if (IS_ERR(right)) |
|
right = NULL; |
|
|
|
/* |
|
* then try to empty the right most buffer into the middle |
|
*/ |
|
if (right) { |
|
u32 right_nr; |
|
|
|
__btrfs_tree_lock(right, BTRFS_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, GFP_NOFS); |
|
BUG_ON(ret < 0); |
|
btrfs_set_node_key(parent, &disk_key, pslot + 1); |
|
btrfs_mark_buffer_dirty(parent); |
|
|
|
if (btrfs_header_nritems(mid) <= orig_slot) { |
|
path->nodes[level] = right; |
|
path->slots[level + 1] += 1; |
|
path->slots[level] = orig_slot - |
|
btrfs_header_nritems(mid); |
|
btrfs_tree_unlock(mid); |
|
free_extent_buffer(mid); |
|
} else { |
|
btrfs_tree_unlock(right); |
|
free_extent_buffer(right); |
|
} |
|
return 0; |
|
} |
|
btrfs_tree_unlock(right); |
|
free_extent_buffer(right); |
|
} |
|
return 1; |
|
} |
|
|
|
/* |
|
* readahead one full node of leaves, finding things that are close |
|
* to the block in 'slot', and triggering ra on them. |
|
*/ |
|
static void reada_for_search(struct btrfs_fs_info *fs_info, |
|
struct btrfs_path *path, |
|
int level, int slot, u64 objectid) |
|
{ |
|
struct extent_buffer *node; |
|
struct btrfs_disk_key disk_key; |
|
u32 nritems; |
|
u64 search; |
|
u64 target; |
|
u64 nread = 0; |
|
u64 nread_max; |
|
struct extent_buffer *eb; |
|
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; |
|
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; |
|
int no_skips = 0; |
|
struct extent_buffer *t; |
|
|
|
for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
|
if (!path->nodes[i]) |
|
break; |
|
if (!path->locks[i]) |
|
break; |
|
if (!no_skips && path->slots[i] == 0) { |
|
skip_level = i + 1; |
|
continue; |
|
} |
|
if (!no_skips && path->keep_locks) { |
|
u32 nritems; |
|
t = path->nodes[i]; |
|
nritems = btrfs_header_nritems(t); |
|
if (nritems < 1 || path->slots[i] >= nritems - 1) { |
|
skip_level = i + 1; |
|
continue; |
|
} |
|
} |
|
if (skip_level < i && i >= lowest_unlock) |
|
no_skips = 1; |
|
|
|
t = path->nodes[i]; |
|
if (i >= lowest_unlock && i > skip_level) { |
|
btrfs_tree_unlock_rw(t, path->locks[i]); |
|
path->locks[i] = 0; |
|
if (write_lock_level && |
|
i > min_write_lock_level && |
|
i <= *write_lock_level) { |
|
*write_lock_level = i - 1; |
|
} |
|
} |
|
} |
|
} |
|
|
|
/* |
|
* helper function for btrfs_search_slot. The goal is to find a block |
|
* in cache without setting the path to blocking. If we find the block |
|
* we return zero and the path is unchanged. |
|
* |
|
* If we can't find the block, we set the path blocking and do some |
|
* reada. -EAGAIN is returned and the search must be repeated. |
|
*/ |
|
static int |
|
read_block_for_search(struct btrfs_root *root, struct btrfs_path *p, |
|
struct extent_buffer **eb_ret, int level, int slot, |
|
const struct btrfs_key *key) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
u64 blocknr; |
|
u64 gen; |
|
struct extent_buffer *tmp; |
|
struct btrfs_key first_key; |
|
int ret; |
|
int parent_level; |
|
|
|
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, &first_key, slot); |
|
|
|
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, &first_key, gen)) { |
|
free_extent_buffer(tmp); |
|
return -EUCLEAN; |
|
} |
|
*eb_ret = tmp; |
|
return 0; |
|
} |
|
|
|
/* now we're allowed to do a blocking uptodate check */ |
|
ret = btrfs_read_buffer(tmp, gen, parent_level - 1, &first_key); |
|
if (!ret) { |
|
*eb_ret = tmp; |
|
return 0; |
|
} |
|
free_extent_buffer(tmp); |
|
btrfs_release_path(p); |
|
return -EIO; |
|
} |
|
|
|
/* |
|
* reduce lock contention at high levels |
|
* of the btree by dropping locks before |
|
* we read. Don't release the lock on the current |
|
* level because we need to walk this node to figure |
|
* out which blocks to read. |
|
*/ |
|
btrfs_unlock_up_safe(p, level + 1); |
|
|
|
if (p->reada != READA_NONE) |
|
reada_for_search(fs_info, p, level, slot, key->objectid); |
|
|
|
ret = -EAGAIN; |
|
tmp = read_tree_block(fs_info, blocknr, root->root_key.objectid, |
|
gen, parent_level - 1, &first_key); |
|
if (!IS_ERR(tmp)) { |
|
/* |
|
* If the read above didn't mark this buffer up to date, |
|
* it will never end up being up to date. Set ret to EIO now |
|
* and give up so that our caller doesn't loop forever |
|
* on our EAGAINs. |
|
*/ |
|
if (!extent_buffer_uptodate(tmp)) |
|
ret = -EIO; |
|
free_extent_buffer(tmp); |
|
} else { |
|
ret = PTR_ERR(tmp); |
|
} |
|
|
|
btrfs_release_path(p); |
|
return ret; |
|
} |
|
|
|
/* |
|
* helper function for btrfs_search_slot. This does all of the checks |
|
* for node-level blocks and does any balancing required based on |
|
* the ins_len. |
|
* |
|
* If no extra work was required, zero is returned. If we had to |
|
* drop the path, -EAGAIN is returned and btrfs_search_slot must |
|
* start over |
|
*/ |
|
static int |
|
setup_nodes_for_search(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, struct btrfs_path *p, |
|
struct extent_buffer *b, int level, int ins_len, |
|
int *write_lock_level) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
int ret = 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 btrfs_fs_info *fs_info = root->fs_info; |
|
struct extent_buffer *b; |
|
int root_lock; |
|
int level = 0; |
|
|
|
/* We try very hard to do read locks on the root */ |
|
root_lock = BTRFS_READ_LOCK; |
|
|
|
if (p->search_commit_root) { |
|
/* |
|
* The commit roots are read only so we always do read locks, |
|
* and we always must hold the commit_root_sem when doing |
|
* searches on them, the only exception is send where we don't |
|
* want to block transaction commits for a long time, so |
|
* we need to clone the commit root in order to avoid races |
|
* with transaction commits that create a snapshot of one of |
|
* the roots used by a send operation. |
|
*/ |
|
if (p->need_commit_sem) { |
|
down_read(&fs_info->commit_root_sem); |
|
b = btrfs_clone_extent_buffer(root->commit_root); |
|
up_read(&fs_info->commit_root_sem); |
|
if (!b) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
} else { |
|
b = root->commit_root; |
|
atomic_inc(&b->refs); |
|
} |
|
level = btrfs_header_level(b); |
|
/* |
|
* Ensure that all callers have set skip_locking when |
|
* p->search_commit_root = 1. |
|
*/ |
|
ASSERT(p->skip_locking == 1); |
|
|
|
goto out; |
|
} |
|
|
|
if (p->skip_locking) { |
|
b = btrfs_root_node(root); |
|
level = btrfs_header_level(b); |
|
goto out; |
|
} |
|
|
|
/* |
|
* If the level is set to maximum, we can skip trying to get the read |
|
* lock. |
|
*/ |
|
if (write_lock_level < BTRFS_MAX_LEVEL) { |
|
/* |
|
* We don't know the level of the root node until we actually |
|
* have it read locked |
|
*/ |
|
b = btrfs_read_lock_root_node(root); |
|
level = btrfs_header_level(b); |
|
if (level > write_lock_level) |
|
goto out; |
|
|
|
/* Whoops, must trade for write lock */ |
|
btrfs_tree_read_unlock(b); |
|
free_extent_buffer(b); |
|
} |
|
|
|
b = btrfs_lock_root_node(root); |
|
root_lock = BTRFS_WRITE_LOCK; |
|
|
|
/* The level might have changed, check again */ |
|
level = btrfs_header_level(b); |
|
|
|
out: |
|
p->nodes[level] = b; |
|
if (!p->skip_locking) |
|
p->locks[level] = root_lock; |
|
/* |
|
* Callers are responsible for dropping b's references. |
|
*/ |
|
return b; |
|
} |
|
|
|
|
|
/* |
|
* btrfs_search_slot - look for a key in a tree and perform necessary |
|
* modifications to preserve tree invariants. |
|
* |
|
* @trans: Handle of transaction, used when modifying the tree |
|
* @p: Holds all btree nodes along the search path |
|
* @root: The root node of the tree |
|
* @key: The key we are looking for |
|
* @ins_len: Indicates purpose of search: |
|
* >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 extent_buffer *b; |
|
int slot; |
|
int ret; |
|
int err; |
|
int level; |
|
int lowest_unlock = 1; |
|
/* everything at write_lock_level or lower must be write locked */ |
|
int write_lock_level = 0; |
|
u8 lowest_level = 0; |
|
int min_write_lock_level; |
|
int prev_cmp; |
|
|
|
lowest_level = p->lowest_level; |
|
WARN_ON(lowest_level && ins_len > 0); |
|
WARN_ON(p->nodes[0] != NULL); |
|
BUG_ON(!cow && ins_len); |
|
|
|
if (ins_len < 0) { |
|
lowest_unlock = 2; |
|
|
|
/* when we are removing items, we might have to go up to level |
|
* two as we update tree pointers Make sure we keep write |
|
* for those levels as well |
|
*/ |
|
write_lock_level = 2; |
|
} else if (ins_len > 0) { |
|
/* |
|
* for inserting items, make sure we have a write lock on |
|
* level 1 so we can update keys |
|
*/ |
|
write_lock_level = 1; |
|
} |
|
|
|
if (!cow) |
|
write_lock_level = -1; |
|
|
|
if (cow && (p->keep_locks || p->lowest_level)) |
|
write_lock_level = BTRFS_MAX_LEVEL; |
|
|
|
min_write_lock_level = write_lock_level; |
|
|
|
again: |
|
prev_cmp = -1; |
|
b = btrfs_search_slot_get_root(root, p, write_lock_level); |
|
if (IS_ERR(b)) { |
|
ret = PTR_ERR(b); |
|
goto done; |
|
} |
|
|
|
while (b) { |
|
int dec = 0; |
|
|
|
level = btrfs_header_level(b); |
|
|
|
if (cow) { |
|
bool last_level = (level == (BTRFS_MAX_LEVEL - 1)); |
|
|
|
/* |
|
* if we don't really need to cow this block |
|
* then we don't want to set the path blocking, |
|
* so we test it here |
|
*/ |
|
if (!should_cow_block(trans, root, b)) |
|
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; |
|
/* |
|
* Leave path with blocking locks to avoid massive |
|
* lock context switch, this is made on purpose. |
|
*/ |
|
|
|
/* |
|
* we have a lock on b and as long as we aren't changing |
|
* the tree, there is no way to for the items in b to change. |
|
* It is safe to drop the lock on our parent before we |
|
* go through the expensive btree search on b. |
|
* |
|
* If we're inserting or deleting (ins_len != 0), then we might |
|
* be changing slot zero, which may require changing the parent. |
|
* So, we can't drop the lock until after we know which slot |
|
* we're operating on. |
|
*/ |
|
if (!ins_len && !p->keep_locks) { |
|
int u = level + 1; |
|
|
|
if (u < BTRFS_MAX_LEVEL && p->locks[u]) { |
|
btrfs_tree_unlock_rw(p->nodes[u], p->locks[u]); |
|
p->locks[u] = 0; |
|
} |
|
} |
|
|
|
/* |
|
* If btrfs_bin_search returns an exact match (prev_cmp == 0) |
|
* we can safely assume the target key will always be in slot 0 |
|
* on lower levels due to the invariants BTRFS' btree provides, |
|
* namely that a btrfs_key_ptr entry always points to the |
|
* lowest key in the child node, thus we can skip searching |
|
* lower levels |
|
*/ |
|
if (prev_cmp == 0) { |
|
slot = 0; |
|
ret = 0; |
|
} else { |
|
ret = btrfs_bin_search(b, key, &slot); |
|
prev_cmp = ret; |
|
if (ret < 0) |
|
goto done; |
|
} |
|
|
|
if (level == 0) { |
|
p->slots[level] = slot; |
|
/* |
|
* 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 && ins_len > 0 && !p->search_for_extension) { |
|
ASSERT(ins_len >= sizeof(struct btrfs_item)); |
|
ins_len -= sizeof(struct btrfs_item); |
|
} |
|
if (ins_len > 0 && |
|
btrfs_leaf_free_space(b) < ins_len) { |
|
if (write_lock_level < 1) { |
|
write_lock_level = 1; |
|
btrfs_release_path(p); |
|
goto again; |
|
} |
|
|
|
err = split_leaf(trans, root, key, |
|
p, ins_len, ret == 0); |
|
|
|
BUG_ON(err > 0); |
|
if (err) { |
|
ret = err; |
|
goto done; |
|
} |
|
} |
|
if (!p->search_for_split) |
|
unlock_up(p, level, lowest_unlock, |
|
min_write_lock_level, NULL); |
|
goto done; |
|
} |
|
if (ret && slot > 0) { |
|
dec = 1; |
|
slot--; |
|
} |
|
p->slots[level] = slot; |
|
err = setup_nodes_for_search(trans, root, p, b, level, ins_len, |
|
&write_lock_level); |
|
if (err == -EAGAIN) |
|
goto again; |
|
if (err) { |
|
ret = err; |
|
goto done; |
|
} |
|
b = p->nodes[level]; |
|
slot = p->slots[level]; |
|
|
|
/* |
|
* Slot 0 is special, if we change the key we have to update |
|
* the parent pointer which means we must have a write lock on |
|
* the parent |
|
*/ |
|
if (slot == 0 && ins_len && write_lock_level < level + 1) { |
|
write_lock_level = level + 1; |
|
btrfs_release_path(p); |
|
goto again; |
|
} |
|
|
|
unlock_up(p, level, lowest_unlock, min_write_lock_level, |
|
&write_lock_level); |
|
|
|
if (level == lowest_level) { |
|
if (dec) |
|
p->slots[level]++; |
|
goto done; |
|
} |
|
|
|
err = read_block_for_search(root, p, &b, level, slot, key); |
|
if (err == -EAGAIN) |
|
goto again; |
|
if (err) { |
|
ret = err; |
|
goto done; |
|
} |
|
|
|
if (!p->skip_locking) { |
|
level = btrfs_header_level(b); |
|
if (level <= write_lock_level) { |
|
btrfs_tree_lock(b); |
|
p->locks[level] = BTRFS_WRITE_LOCK; |
|
} 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); |
|
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); |
|
|
|
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, 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; |
|
} |
|
|
|
/* |
|
* helper to use instead of search slot if no exact match is needed but |
|
* instead the next or previous item should be returned. |
|
* When find_higher is true, the next higher item is returned, the next lower |
|
* otherwise. |
|
* When return_any and find_higher are both true, and no higher item is found, |
|
* return the next lower instead. |
|
* When return_any is true and find_higher is false, and no lower item is found, |
|
* return the next higher instead. |
|
* It returns 0 if any item is found, 1 if none is found (tree empty), and |
|
* < 0 on error |
|
*/ |
|
int btrfs_search_slot_for_read(struct btrfs_root *root, |
|
const struct btrfs_key *key, |
|
struct btrfs_path *p, int find_higher, |
|
int return_any) |
|
{ |
|
int ret; |
|
struct extent_buffer *leaf; |
|
|
|
again: |
|
ret = btrfs_search_slot(NULL, root, key, p, 0, 0); |
|
if (ret <= 0) |
|
return ret; |
|
/* |
|
* a return value of 1 means the path is at the position where the |
|
* item should be inserted. Normally this is the next bigger item, |
|
* but in case the previous item is the last in a leaf, path points |
|
* to the first free slot in the previous leaf, i.e. at an invalid |
|
* item. |
|
*/ |
|
leaf = p->nodes[0]; |
|
|
|
if (find_higher) { |
|
if (p->slots[0] >= btrfs_header_nritems(leaf)) { |
|
ret = btrfs_next_leaf(root, p); |
|
if (ret <= 0) |
|
return ret; |
|
if (!return_any) |
|
return 1; |
|
/* |
|
* no higher item found, return the next |
|
* lower instead |
|
*/ |
|
return_any = 0; |
|
find_higher = 0; |
|
btrfs_release_path(p); |
|
goto again; |
|
} |
|
} else { |
|
if (p->slots[0] == 0) { |
|
ret = btrfs_prev_leaf(root, p); |
|
if (ret < 0) |
|
return ret; |
|
if (!ret) { |
|
leaf = p->nodes[0]; |
|
if (p->slots[0] == btrfs_header_nritems(leaf)) |
|
p->slots[0]--; |
|
return 0; |
|
} |
|
if (!return_any) |
|
return 1; |
|
/* |
|
* no lower item found, return the next |
|
* higher instead |
|
*/ |
|
return_any = 0; |
|
find_higher = 1; |
|
btrfs_release_path(p); |
|
goto again; |
|
} else { |
|
--p->slots[0]; |
|
} |
|
} |
|
return 0; |
|
} |
|
|
|
/* |
|
* adjust the pointers going up the tree, starting at level |
|
* making sure the right key of each node is points to 'key'. |
|
* This is used after shifting pointers to the left, so it stops |
|
* fixing up pointers when a given leaf/node is not in slot 0 of the |
|
* higher levels |
|
* |
|
*/ |
|
static void fixup_low_keys(struct btrfs_path *path, |
|
struct btrfs_disk_key *key, int level) |
|
{ |
|
int i; |
|
struct extent_buffer *t; |
|
int ret; |
|
|
|
for (i = level; i < BTRFS_MAX_LEVEL; i++) { |
|
int tslot = path->slots[i]; |
|
|
|
if (!path->nodes[i]) |
|
break; |
|
t = path->nodes[i]; |
|
ret = btrfs_tree_mod_log_insert_key(t, tslot, |
|
BTRFS_MOD_LOG_KEY_REPLACE, GFP_ATOMIC); |
|
BUG_ON(ret < 0); |
|
btrfs_set_node_key(t, key, tslot); |
|
btrfs_mark_buffer_dirty(path->nodes[i]); |
|
if (tslot != 0) |
|
break; |
|
} |
|
} |
|
|
|
/* |
|
* update item key. |
|
* |
|
* This function isn't completely safe. It's the caller's responsibility |
|
* that the new key won't break the order |
|
*/ |
|
void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info, |
|
struct btrfs_path *path, |
|
const struct btrfs_key *new_key) |
|
{ |
|
struct btrfs_disk_key disk_key; |
|
struct extent_buffer *eb; |
|
int slot; |
|
|
|
eb = path->nodes[0]; |
|
slot = path->slots[0]; |
|
if (slot > 0) { |
|
btrfs_item_key(eb, &disk_key, slot - 1); |
|
if (unlikely(comp_keys(&disk_key, new_key) >= 0)) { |
|
btrfs_crit(fs_info, |
|
"slot %u key (%llu %u %llu) new key (%llu %u %llu)", |
|
slot, btrfs_disk_key_objectid(&disk_key), |
|
btrfs_disk_key_type(&disk_key), |
|
btrfs_disk_key_offset(&disk_key), |
|
new_key->objectid, new_key->type, |
|
new_key->offset); |
|
btrfs_print_leaf(eb); |
|
BUG(); |
|
} |
|
} |
|
if (slot < btrfs_header_nritems(eb) - 1) { |
|
btrfs_item_key(eb, &disk_key, slot + 1); |
|
if (unlikely(comp_keys(&disk_key, new_key) <= 0)) { |
|
btrfs_crit(fs_info, |
|
"slot %u key (%llu %u %llu) new key (%llu %u %llu)", |
|
slot, btrfs_disk_key_objectid(&disk_key), |
|
btrfs_disk_key_type(&disk_key), |
|
btrfs_disk_key_offset(&disk_key), |
|
new_key->objectid, new_key->type, |
|
new_key->offset); |
|
btrfs_print_leaf(eb); |
|
BUG(); |
|
} |
|
} |
|
|
|
btrfs_cpu_key_to_disk(&disk_key, new_key); |
|
btrfs_set_item_key(eb, &disk_key, slot); |
|
btrfs_mark_buffer_dirty(eb); |
|
if (slot == 0) |
|
fixup_low_keys(path, &disk_key, 1); |
|
} |
|
|
|
/* |
|
* 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 (btrfs_comp_cpu_keys(&left_last, &right_first) >= 0) { |
|
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_nritems), |
|
btrfs_node_key_ptr_offset(0), |
|
push_items * sizeof(struct btrfs_key_ptr)); |
|
|
|
if (push_items < src_nritems) { |
|
/* |
|
* Don't call btrfs_tree_mod_log_insert_move() here, key removal |
|
* was already fully logged by btrfs_tree_mod_log_eb_copy() above. |
|
*/ |
|
memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0), |
|
btrfs_node_key_ptr_offset(push_items), |
|
(src_nritems - push_items) * |
|
sizeof(struct btrfs_key_ptr)); |
|
} |
|
btrfs_set_header_nritems(src, src_nritems - push_items); |
|
btrfs_set_header_nritems(dst, dst_nritems + push_items); |
|
btrfs_mark_buffer_dirty(src); |
|
btrfs_mark_buffer_dirty(dst); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* try to push data from one node into the next node right in the |
|
* tree. |
|
* |
|
* returns 0 if some ptrs were pushed, < 0 if there was some horrible |
|
* error, and > 0 if there was no room in the right hand block. |
|
* |
|
* this will only push up to 1/2 the contents of the left node over |
|
*/ |
|
static int balance_node_right(struct btrfs_trans_handle *trans, |
|
struct extent_buffer *dst, |
|
struct extent_buffer *src) |
|
{ |
|
struct btrfs_fs_info *fs_info = trans->fs_info; |
|
int push_items = 0; |
|
int max_push; |
|
int src_nritems; |
|
int dst_nritems; |
|
int ret = 0; |
|
|
|
WARN_ON(btrfs_header_generation(src) != trans->transid); |
|
WARN_ON(btrfs_header_generation(dst) != trans->transid); |
|
|
|
src_nritems = btrfs_header_nritems(src); |
|
dst_nritems = btrfs_header_nritems(dst); |
|
push_items = BTRFS_NODEPTRS_PER_BLOCK(fs_info) - dst_nritems; |
|
if (push_items <= 0) |
|
return 1; |
|
|
|
if (src_nritems < 4) |
|
return 1; |
|
|
|
max_push = src_nritems / 2 + 1; |
|
/* don't try to empty the node */ |
|
if (max_push >= src_nritems) |
|
return 1; |
|
|
|
if (max_push < push_items) |
|
push_items = max_push; |
|
|
|
/* 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; |
|
} |
|
ret = btrfs_tree_mod_log_insert_move(dst, push_items, 0, dst_nritems); |
|
BUG_ON(ret < 0); |
|
memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items), |
|
btrfs_node_key_ptr_offset(0), |
|
(dst_nritems) * |
|
sizeof(struct btrfs_key_ptr)); |
|
|
|
ret = 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(0), |
|
btrfs_node_key_ptr_offset(src_nritems - push_items), |
|
push_items * sizeof(struct btrfs_key_ptr)); |
|
|
|
btrfs_set_header_nritems(src, src_nritems - push_items); |
|
btrfs_set_header_nritems(dst, dst_nritems + push_items); |
|
|
|
btrfs_mark_buffer_dirty(src); |
|
btrfs_mark_buffer_dirty(dst); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* helper function to insert a new root level in the tree. |
|
* A new node is allocated, and a single item is inserted to |
|
* point to the existing root |
|
* |
|
* returns zero on success or < 0 on failure. |
|
*/ |
|
static noinline int insert_new_root(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, int level) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
u64 lower_gen; |
|
struct extent_buffer *lower; |
|
struct extent_buffer *c; |
|
struct extent_buffer *old; |
|
struct btrfs_disk_key lower_key; |
|
int ret; |
|
|
|
BUG_ON(path->nodes[level]); |
|
BUG_ON(path->nodes[level-1] != root->node); |
|
|
|
lower = path->nodes[level-1]; |
|
if (level == 1) |
|
btrfs_item_key(lower, &lower_key, 0); |
|
else |
|
btrfs_node_key(lower, &lower_key, 0); |
|
|
|
c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, |
|
&lower_key, level, root->node->start, 0, |
|
BTRFS_NESTING_NEW_ROOT); |
|
if (IS_ERR(c)) |
|
return PTR_ERR(c); |
|
|
|
root_add_used(root, fs_info->nodesize); |
|
|
|
btrfs_set_header_nritems(c, 1); |
|
btrfs_set_node_key(c, &lower_key, 0); |
|
btrfs_set_node_blockptr(c, 0, lower->start); |
|
lower_gen = btrfs_header_generation(lower); |
|
WARN_ON(lower_gen != trans->transid); |
|
|
|
btrfs_set_node_ptr_generation(c, 0, lower_gen); |
|
|
|
btrfs_mark_buffer_dirty(c); |
|
|
|
old = root->node; |
|
ret = btrfs_tree_mod_log_insert_root(root->node, c, false); |
|
BUG_ON(ret < 0); |
|
rcu_assign_pointer(root->node, c); |
|
|
|
/* the super has an extra ref to root->node */ |
|
free_extent_buffer(old); |
|
|
|
add_root_to_dirty_list(root); |
|
atomic_inc(&c->refs); |
|
path->nodes[level] = c; |
|
path->locks[level] = BTRFS_WRITE_LOCK; |
|
path->slots[level] = 0; |
|
return 0; |
|
} |
|
|
|
/* |
|
* worker function to insert a single pointer in a node. |
|
* the node should have enough room for the pointer already |
|
* |
|
* slot and level indicate where you want the key to go, and |
|
* blocknr is the block the key points to. |
|
*/ |
|
static void insert_ptr(struct btrfs_trans_handle *trans, |
|
struct btrfs_path *path, |
|
struct btrfs_disk_key *key, u64 bytenr, |
|
int slot, int level) |
|
{ |
|
struct extent_buffer *lower; |
|
int nritems; |
|
int ret; |
|
|
|
BUG_ON(!path->nodes[level]); |
|
btrfs_assert_tree_locked(path->nodes[level]); |
|
lower = path->nodes[level]; |
|
nritems = btrfs_header_nritems(lower); |
|
BUG_ON(slot > nritems); |
|
BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(trans->fs_info)); |
|
if (slot != nritems) { |
|
if (level) { |
|
ret = btrfs_tree_mod_log_insert_move(lower, slot + 1, |
|
slot, nritems - slot); |
|
BUG_ON(ret < 0); |
|
} |
|
memmove_extent_buffer(lower, |
|
btrfs_node_key_ptr_offset(slot + 1), |
|
btrfs_node_key_ptr_offset(slot), |
|
(nritems - slot) * sizeof(struct btrfs_key_ptr)); |
|
} |
|
if (level) { |
|
ret = btrfs_tree_mod_log_insert_key(lower, slot, |
|
BTRFS_MOD_LOG_KEY_ADD, GFP_NOFS); |
|
BUG_ON(ret < 0); |
|
} |
|
btrfs_set_node_key(lower, key, slot); |
|
btrfs_set_node_blockptr(lower, slot, bytenr); |
|
WARN_ON(trans->transid == 0); |
|
btrfs_set_node_ptr_generation(lower, slot, trans->transid); |
|
btrfs_set_header_nritems(lower, nritems + 1); |
|
btrfs_mark_buffer_dirty(lower); |
|
} |
|
|
|
/* |
|
* split the node at the specified level in path in two. |
|
* The path is corrected to point to the appropriate node after the split |
|
* |
|
* Before splitting this tries to make some room in the node by pushing |
|
* left and right, if either one works, it returns right away. |
|
* |
|
* returns 0 on success and < 0 on failure |
|
*/ |
|
static noinline int split_node(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, int level) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
struct extent_buffer *c; |
|
struct extent_buffer *split; |
|
struct btrfs_disk_key disk_key; |
|
int mid; |
|
int ret; |
|
u32 c_nritems; |
|
|
|
c = path->nodes[level]; |
|
WARN_ON(btrfs_header_generation(c) != trans->transid); |
|
if (c == root->node) { |
|
/* |
|
* trying to split the root, lets make a new one |
|
* |
|
* tree mod log: We don't log_removal old root in |
|
* insert_new_root, because that root buffer will be kept as a |
|
* normal node. We are going to log removal of half of the |
|
* elements below with btrfs_tree_mod_log_eb_copy(). We're |
|
* holding a tree lock on the buffer, which is why we cannot |
|
* race with other tree_mod_log users. |
|
*/ |
|
ret = insert_new_root(trans, root, path, level + 1); |
|
if (ret) |
|
return ret; |
|
} else { |
|
ret = push_nodes_for_insert(trans, root, path, level); |
|
c = path->nodes[level]; |
|
if (!ret && btrfs_header_nritems(c) < |
|
BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) |
|
return 0; |
|
if (ret < 0) |
|
return ret; |
|
} |
|
|
|
c_nritems = btrfs_header_nritems(c); |
|
mid = (c_nritems + 1) / 2; |
|
btrfs_node_key(c, &disk_key, mid); |
|
|
|
split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, |
|
&disk_key, level, c->start, 0, |
|
BTRFS_NESTING_SPLIT); |
|
if (IS_ERR(split)) |
|
return PTR_ERR(split); |
|
|
|
root_add_used(root, fs_info->nodesize); |
|
ASSERT(btrfs_header_level(c) == level); |
|
|
|
ret = btrfs_tree_mod_log_eb_copy(split, c, 0, mid, c_nritems - mid); |
|
if (ret) { |
|
btrfs_abort_transaction(trans, ret); |
|
return ret; |
|
} |
|
copy_extent_buffer(split, c, |
|
btrfs_node_key_ptr_offset(0), |
|
btrfs_node_key_ptr_offset(mid), |
|
(c_nritems - mid) * sizeof(struct btrfs_key_ptr)); |
|
btrfs_set_header_nritems(split, c_nritems - mid); |
|
btrfs_set_header_nritems(c, mid); |
|
|
|
btrfs_mark_buffer_dirty(c); |
|
btrfs_mark_buffer_dirty(split); |
|
|
|
insert_ptr(trans, path, &disk_key, split->start, |
|
path->slots[level + 1] + 1, level + 1); |
|
|
|
if (path->slots[level] >= mid) { |
|
path->slots[level] -= mid; |
|
btrfs_tree_unlock(c); |
|
free_extent_buffer(c); |
|
path->nodes[level] = split; |
|
path->slots[level + 1] += 1; |
|
} else { |
|
btrfs_tree_unlock(split); |
|
free_extent_buffer(split); |
|
} |
|
return 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(struct extent_buffer *l, int start, int nr) |
|
{ |
|
struct btrfs_item *start_item; |
|
struct btrfs_item *end_item; |
|
int data_len; |
|
int nritems = btrfs_header_nritems(l); |
|
int end = min(nritems, start + nr) - 1; |
|
|
|
if (!nr) |
|
return 0; |
|
start_item = btrfs_item_nr(start); |
|
end_item = btrfs_item_nr(end); |
|
data_len = btrfs_item_offset(l, start_item) + |
|
btrfs_item_size(l, start_item); |
|
data_len = data_len - btrfs_item_offset(l, end_item); |
|
data_len += sizeof(struct btrfs_item) * nr; |
|
WARN_ON(data_len < 0); |
|
return data_len; |
|
} |
|
|
|
/* |
|
* The space between the end of the leaf items and |
|
* the start of the leaf data. IOW, how much room |
|
* the leaf has left for both items and data |
|
*/ |
|
noinline int btrfs_leaf_free_space(struct extent_buffer *leaf) |
|
{ |
|
struct btrfs_fs_info *fs_info = leaf->fs_info; |
|
int nritems = btrfs_header_nritems(leaf); |
|
int ret; |
|
|
|
ret = BTRFS_LEAF_DATA_SIZE(fs_info) - leaf_space_used(leaf, 0, nritems); |
|
if (ret < 0) { |
|
btrfs_crit(fs_info, |
|
"leaf free space ret %d, leaf data size %lu, used %d nritems %d", |
|
ret, |
|
(unsigned long) BTRFS_LEAF_DATA_SIZE(fs_info), |
|
leaf_space_used(leaf, 0, nritems), nritems); |
|
} |
|
return ret; |
|
} |
|
|
|
/* |
|
* min slot controls the lowest index we're willing to push to the |
|
* right. We'll push up to and including min_slot, but no lower |
|
*/ |
|
static noinline int __push_leaf_right(struct btrfs_path *path, |
|
int data_size, int empty, |
|
struct extent_buffer *right, |
|
int free_space, u32 left_nritems, |
|
u32 min_slot) |
|
{ |
|
struct btrfs_fs_info *fs_info = right->fs_info; |
|
struct extent_buffer *left = path->nodes[0]; |
|
struct extent_buffer *upper = path->nodes[1]; |
|
struct btrfs_map_token token; |
|
struct btrfs_disk_key disk_key; |
|
int slot; |
|
u32 i; |
|
int push_space = 0; |
|
int push_items = 0; |
|
struct btrfs_item *item; |
|
u32 nr; |
|
u32 right_nritems; |
|
u32 data_end; |
|
u32 this_item_size; |
|
|
|
if (empty) |
|
nr = 0; |
|
else |
|
nr = max_t(u32, 1, min_slot); |
|
|
|
if (path->slots[0] >= left_nritems) |
|
push_space += data_size; |
|
|
|
slot = path->slots[1]; |
|
i = left_nritems - 1; |
|
while (i >= nr) { |
|
item = btrfs_item_nr(i); |
|
|
|
if (!empty && push_items > 0) { |
|
if (path->slots[0] > i) |
|
break; |
|
if (path->slots[0] == i) { |
|
int space = btrfs_leaf_free_space(left); |
|
|
|
if (space + push_space * 2 > free_space) |
|
break; |
|
} |
|
} |
|
|
|
if (path->slots[0] == i) |
|
push_space += data_size; |
|
|
|
this_item_size = btrfs_item_size(left, item); |
|
if (this_item_size + sizeof(*item) + push_space > free_space) |
|
break; |
|
|
|
push_items++; |
|
push_space += this_item_size + sizeof(*item); |
|
if (i == 0) |
|
break; |
|
i--; |
|
} |
|
|
|
if (push_items == 0) |
|
goto out_unlock; |
|
|
|
WARN_ON(!empty && push_items == left_nritems); |
|
|
|
/* push left to right */ |
|
right_nritems = btrfs_header_nritems(right); |
|
|
|
push_space = btrfs_item_end_nr(left, left_nritems - push_items); |
|
push_space -= leaf_data_end(left); |
|
|
|
/* make room in the right data area */ |
|
data_end = leaf_data_end(right); |
|
memmove_extent_buffer(right, |
|
BTRFS_LEAF_DATA_OFFSET + data_end - push_space, |
|
BTRFS_LEAF_DATA_OFFSET + data_end, |
|
BTRFS_LEAF_DATA_SIZE(fs_info) - data_end); |
|
|
|
/* copy from the left data area */ |
|
copy_extent_buffer(right, left, BTRFS_LEAF_DATA_OFFSET + |
|
BTRFS_LEAF_DATA_SIZE(fs_info) - push_space, |
|
BTRFS_LEAF_DATA_OFFSET + leaf_data_end(left), |
|
push_space); |
|
|
|
memmove_extent_buffer(right, btrfs_item_nr_offset(push_items), |
|
btrfs_item_nr_offset(0), |
|
right_nritems * sizeof(struct btrfs_item)); |
|
|
|
/* copy the items from left to right */ |
|
copy_extent_buffer(right, left, btrfs_item_nr_offset(0), |
|
btrfs_item_nr_offset(left_nritems - push_items), |
|
push_items * sizeof(struct btrfs_item)); |
|
|
|
/* update the item pointers */ |
|
btrfs_init_map_token(&token, right); |
|
right_nritems += push_items; |
|
btrfs_set_header_nritems(right, right_nritems); |
|
push_space = BTRFS_LEAF_DATA_SIZE(fs_info); |
|
for (i = 0; i < right_nritems; i++) { |
|
item = btrfs_item_nr(i); |
|
push_space -= btrfs_token_item_size(&token, item); |
|
btrfs_set_token_item_offset(&token, item, push_space); |
|
} |
|
|
|
left_nritems -= push_items; |
|
btrfs_set_header_nritems(left, left_nritems); |
|
|
|
if (left_nritems) |
|
btrfs_mark_buffer_dirty(left); |
|
else |
|
btrfs_clean_tree_block(left); |
|
|
|
btrfs_mark_buffer_dirty(right); |
|
|
|
btrfs_item_key(right, &disk_key, 0); |
|
btrfs_set_node_key(upper, &disk_key, slot + 1); |
|
btrfs_mark_buffer_dirty(upper); |
|
|
|
/* then fixup the leaf pointer in the path */ |
|
if (path->slots[0] >= left_nritems) { |
|
path->slots[0] -= left_nritems; |
|
if (btrfs_header_nritems(path->nodes[0]) == 0) |
|
btrfs_clean_tree_block(path->nodes[0]); |
|
btrfs_tree_unlock(path->nodes[0]); |
|
free_extent_buffer(path->nodes[0]); |
|
path->nodes[0] = right; |
|
path->slots[1] += 1; |
|
} else { |
|
btrfs_tree_unlock(right); |
|
free_extent_buffer(right); |
|
} |
|
return 0; |
|
|
|
out_unlock: |
|
btrfs_tree_unlock(right); |
|
free_extent_buffer(right); |
|
return 1; |
|
} |
|
|
|
/* |
|
* push some data in the path leaf to the right, trying to free up at |
|
* least data_size bytes. returns zero if the push worked, nonzero otherwise |
|
* |
|
* returns 1 if the push failed because the other node didn't have enough |
|
* room, 0 if everything worked out and < 0 if there were major errors. |
|
* |
|
* this will push starting from min_slot to the end of the leaf. It won't |
|
* push any slot lower than min_slot |
|
*/ |
|
static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root |
|
*root, struct btrfs_path *path, |
|
int min_data_size, int data_size, |
|
int empty, u32 min_slot) |
|
{ |
|
struct extent_buffer *left = path->nodes[0]; |
|
struct extent_buffer *right; |
|
struct extent_buffer *upper; |
|
int slot; |
|
int free_space; |
|
u32 left_nritems; |
|
int ret; |
|
|
|
if (!path->nodes[1]) |
|
return 1; |
|
|
|
slot = path->slots[1]; |
|
upper = path->nodes[1]; |
|
if (slot >= btrfs_header_nritems(upper) - 1) |
|
return 1; |
|
|
|
btrfs_assert_tree_locked(path->nodes[1]); |
|
|
|
right = btrfs_read_node_slot(upper, slot + 1); |
|
/* |
|
* slot + 1 is not valid or we fail to read the right node, |
|
* no big deal, just return. |
|
*/ |
|
if (IS_ERR(right)) |
|
return 1; |
|
|
|
__btrfs_tree_lock(right, BTRFS_NESTING_RIGHT); |
|
|
|
free_space = btrfs_leaf_free_space(right); |
|
if (free_space < data_size) |
|
goto out_unlock; |
|
|
|
/* cow and double check */ |
|
ret = btrfs_cow_block(trans, root, right, upper, |
|
slot + 1, &right, BTRFS_NESTING_RIGHT_COW); |
|
if (ret) |
|
goto out_unlock; |
|
|
|
free_space = btrfs_leaf_free_space(right); |
|
if (free_space < data_size) |
|
goto out_unlock; |
|
|
|
left_nritems = btrfs_header_nritems(left); |
|
if (left_nritems == 0) |
|
goto out_unlock; |
|
|
|
if (check_sibling_keys(left, right)) { |
|
ret = -EUCLEAN; |
|
btrfs_tree_unlock(right); |
|
free_extent_buffer(right); |
|
return ret; |
|
} |
|
if (path->slots[0] == left_nritems && !empty) { |
|
/* Key greater than all keys in the leaf, right neighbor has |
|
* enough room for it and we're not emptying our leaf to delete |
|
* it, therefore use right neighbor to insert the new item and |
|
* no need to touch/dirty our left leaf. */ |
|
btrfs_tree_unlock(left); |
|
free_extent_buffer(left); |
|
path->nodes[0] = right; |
|
path->slots[0] = 0; |
|
path->slots[1]++; |
|
return 0; |
|
} |
|
|
|
return __push_leaf_right(path, min_data_size, empty, |
|
right, free_space, left_nritems, min_slot); |
|
out_unlock: |
|
btrfs_tree_unlock(right); |
|
free_extent_buffer(right); |
|
return 1; |
|
} |
|
|
|
/* |
|
* push some data in the path leaf to the left, trying to free up at |
|
* least data_size bytes. returns zero if the push worked, nonzero otherwise |
|
* |
|
* max_slot can put a limit on how far into the leaf we'll push items. The |
|
* item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the |
|
* items |
|
*/ |
|
static noinline int __push_leaf_left(struct btrfs_path *path, int data_size, |
|
int empty, struct extent_buffer *left, |
|
int free_space, u32 right_nritems, |
|
u32 max_slot) |
|
{ |
|
struct btrfs_fs_info *fs_info = left->fs_info; |
|
struct btrfs_disk_key disk_key; |
|
struct extent_buffer *right = path->nodes[0]; |
|
int i; |
|
int push_space = 0; |
|
int push_items = 0; |
|
struct btrfs_item *item; |
|
u32 old_left_nritems; |
|
u32 nr; |
|
int ret = 0; |
|
u32 this_item_size; |
|
u32 old_left_item_size; |
|
struct btrfs_map_token token; |
|
|
|
if (empty) |
|
nr = min(right_nritems, max_slot); |
|
else |
|
nr = min(right_nritems - 1, max_slot); |
|
|
|
for (i = 0; i < nr; i++) { |
|
item = btrfs_item_nr(i); |
|
|
|
if (!empty && push_items > 0) { |
|
if (path->slots[0] < i) |
|
break; |
|
if (path->slots[0] == i) { |
|
int space = btrfs_leaf_free_space(right); |
|
|
|
if (space + push_space * 2 > free_space) |
|
break; |
|
} |
|
} |
|
|
|
if (path->slots[0] == i) |
|
push_space += data_size; |
|
|
|
this_item_size = btrfs_item_size(right, item); |
|
if (this_item_size + sizeof(*item) + push_space > free_space) |
|
break; |
|
|
|
push_items++; |
|
push_space += this_item_size + sizeof(*item); |
|
} |
|
|
|
if (push_items == 0) { |
|
ret = 1; |
|
goto out; |
|
} |
|
WARN_ON(!empty && push_items == btrfs_header_nritems(right)); |
|
|
|
/* push data from right to left */ |
|
copy_extent_buffer(left, right, |
|
btrfs_item_nr_offset(btrfs_header_nritems(left)), |
|
btrfs_item_nr_offset(0), |
|
push_items * sizeof(struct btrfs_item)); |
|
|
|
push_space = BTRFS_LEAF_DATA_SIZE(fs_info) - |
|
btrfs_item_offset_nr(right, push_items - 1); |
|
|
|
copy_extent_buffer(left, right, BTRFS_LEAF_DATA_OFFSET + |
|
leaf_data_end(left) - push_space, |
|
BTRFS_LEAF_DATA_OFFSET + |
|
btrfs_item_offset_nr(right, push_items - 1), |
|
push_space); |
|
old_left_nritems = btrfs_header_nritems(left); |
|
BUG_ON(old_left_nritems <= 0); |
|
|
|
btrfs_init_map_token(&token, left); |
|
old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1); |
|
for (i = old_left_nritems; i < old_left_nritems + push_items; i++) { |
|
u32 ioff; |
|
|
|
item = btrfs_item_nr(i); |
|
|
|
ioff = btrfs_token_item_offset(&token, item); |
|
btrfs_set_token_item_offset(&token, item, |
|
ioff - (BTRFS_LEAF_DATA_SIZE(fs_info) - old_left_item_size)); |
|
} |
|
btrfs_set_header_nritems(left, old_left_nritems + push_items); |
|
|
|
/* fixup right node */ |
|
if (push_items > right_nritems) |
|
WARN(1, KERN_CRIT "push items %d nr %u\n", push_items, |
|
right_nritems); |
|
|
|
if (push_items < right_nritems) { |
|
push_space = btrfs_item_offset_nr(right, push_items - 1) - |
|
leaf_data_end(right); |
|
memmove_extent_buffer(right, BTRFS_LEAF_DATA_OFFSET + |
|
BTRFS_LEAF_DATA_SIZE(fs_info) - push_space, |
|
BTRFS_LEAF_DATA_OFFSET + |
|
leaf_data_end(right), push_space); |
|
|
|
memmove_extent_buffer(right, btrfs_item_nr_offset(0), |
|
btrfs_item_nr_offset(push_items), |
|
(btrfs_header_nritems(right) - push_items) * |
|
sizeof(struct btrfs_item)); |
|
} |
|
|
|
btrfs_init_map_token(&token, right); |
|
right_nritems -= push_items; |
|
btrfs_set_header_nritems(right, right_nritems); |
|
push_space = BTRFS_LEAF_DATA_SIZE(fs_info); |
|
for (i = 0; i < right_nritems; i++) { |
|
item = btrfs_item_nr(i); |
|
|
|
push_space = push_space - btrfs_token_item_size(&token, item); |
|
btrfs_set_token_item_offset(&token, item, push_space); |
|
} |
|
|
|
btrfs_mark_buffer_dirty(left); |
|
if (right_nritems) |
|
btrfs_mark_buffer_dirty(right); |
|
else |
|
btrfs_clean_tree_block(right); |
|
|
|
btrfs_item_key(right, &disk_key, 0); |
|
fixup_low_keys(path, &disk_key, 1); |
|
|
|
/* then fixup the leaf pointer in the path */ |
|
if (path->slots[0] < push_items) { |
|
path->slots[0] += old_left_nritems; |
|
btrfs_tree_unlock(path->nodes[0]); |
|
free_extent_buffer(path->nodes[0]); |
|
path->nodes[0] = left; |
|
path->slots[1] -= 1; |
|
} else { |
|
btrfs_tree_unlock(left); |
|
free_extent_buffer(left); |
|
path->slots[0] -= push_items; |
|
} |
|
BUG_ON(path->slots[0] < 0); |
|
return ret; |
|
out: |
|
btrfs_tree_unlock(left); |
|
free_extent_buffer(left); |
|
return ret; |
|
} |
|
|
|
/* |
|
* push some data in the path leaf to the left, trying to free up at |
|
* least data_size bytes. returns zero if the push worked, nonzero otherwise |
|
* |
|
* max_slot can put a limit on how far into the leaf we'll push items. The |
|
* item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the |
|
* items |
|
*/ |
|
static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root |
|
*root, struct btrfs_path *path, int min_data_size, |
|
int data_size, int empty, u32 max_slot) |
|
{ |
|
struct extent_buffer *right = path->nodes[0]; |
|
struct extent_buffer *left; |
|
int slot; |
|
int free_space; |
|
u32 right_nritems; |
|
int ret = 0; |
|
|
|
slot = path->slots[1]; |
|
if (slot == 0) |
|
return 1; |
|
if (!path->nodes[1]) |
|
return 1; |
|
|
|
right_nritems = btrfs_header_nritems(right); |
|
if (right_nritems == 0) |
|
return 1; |
|
|
|
btrfs_assert_tree_locked(path->nodes[1]); |
|
|
|
left = btrfs_read_node_slot(path->nodes[1], slot - 1); |
|
/* |
|
* slot - 1 is not valid or we fail to read the left node, |
|
* no big deal, just return. |
|
*/ |
|
if (IS_ERR(left)) |
|
return 1; |
|
|
|
__btrfs_tree_lock(left, BTRFS_NESTING_LEFT); |
|
|
|
free_space = btrfs_leaf_free_space(left); |
|
if (free_space < data_size) { |
|
ret = 1; |
|
goto out; |
|
} |
|
|
|
/* cow and double check */ |
|
ret = btrfs_cow_block(trans, root, left, |
|
path->nodes[1], slot - 1, &left, |
|
BTRFS_NESTING_LEFT_COW); |
|
if (ret) { |
|
/* we hit -ENOSPC, but it isn't fatal here */ |
|
if (ret == -ENOSPC) |
|
ret = 1; |
|
goto out; |
|
} |
|
|
|
free_space = btrfs_leaf_free_space(left); |
|
if (free_space < data_size) { |
|
ret = 1; |
|
goto out; |
|
} |
|
|
|
if (check_sibling_keys(left, right)) { |
|
ret = -EUCLEAN; |
|
goto out; |
|
} |
|
return __push_leaf_left(path, min_data_size, |
|
empty, left, free_space, right_nritems, |
|
max_slot); |
|
out: |
|
btrfs_tree_unlock(left); |
|
free_extent_buffer(left); |
|
return ret; |
|
} |
|
|
|
/* |
|
* split the path's leaf in two, making sure there is at least data_size |
|
* available for the resulting leaf level of the path. |
|
*/ |
|
static noinline void copy_for_split(struct btrfs_trans_handle *trans, |
|
struct btrfs_path *path, |
|
struct extent_buffer *l, |
|
struct extent_buffer *right, |
|
int slot, int mid, int nritems) |
|
{ |
|
struct btrfs_fs_info *fs_info = trans->fs_info; |
|
int data_copy_size; |
|
int rt_data_off; |
|
int i; |
|
struct btrfs_disk_key disk_key; |
|
struct btrfs_map_token token; |
|
|
|
nritems = nritems - mid; |
|
btrfs_set_header_nritems(right, nritems); |
|
data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(l); |
|
|
|
copy_extent_buffer(right, l, btrfs_item_nr_offset(0), |
|
btrfs_item_nr_offset(mid), |
|
nritems * sizeof(struct btrfs_item)); |
|
|
|
copy_extent_buffer(right, l, |
|
BTRFS_LEAF_DATA_OFFSET + BTRFS_LEAF_DATA_SIZE(fs_info) - |
|
data_copy_size, BTRFS_LEAF_DATA_OFFSET + |
|
leaf_data_end(l), data_copy_size); |
|
|
|
rt_data_off = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_end_nr(l, mid); |
|
|
|
btrfs_init_map_token(&token, right); |
|
for (i = 0; i < nritems; i++) { |
|
struct btrfs_item *item = btrfs_item_nr(i); |
|
u32 ioff; |
|
|
|
ioff = btrfs_token_item_offset(&token, item); |
|
btrfs_set_token_item_offset(&token, item, ioff + rt_data_off); |
|
} |
|
|
|
btrfs_set_header_nritems(l, mid); |
|
btrfs_item_key(right, &disk_key, 0); |
|
insert_ptr(trans, path, &disk_key, right->start, path->slots[1] + 1, 1); |
|
|
|
btrfs_mark_buffer_dirty(right); |
|
btrfs_mark_buffer_dirty(l); |
|
BUG_ON(path->slots[0] != slot); |
|
|
|
if (mid <= slot) { |
|
btrfs_tree_unlock(path->nodes[0]); |
|
free_extent_buffer(path->nodes[0]); |
|
path->nodes[0] = right; |
|
path->slots[0] -= mid; |
|
path->slots[1] += 1; |
|
} else { |
|
btrfs_tree_unlock(right); |
|
free_extent_buffer(right); |
|
} |
|
|
|
BUG_ON(path->slots[0] < 0); |
|
} |
|
|
|
/* |
|
* double splits happen when we need to insert a big item in the middle |
|
* of a leaf. A double split can leave us with 3 mostly empty leaves: |
|
* leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ] |
|
* A B C |
|
* |
|
* We avoid this by trying to push the items on either side of our target |
|
* into the adjacent leaves. If all goes well we can avoid the double split |
|
* completely. |
|
*/ |
|
static noinline int push_for_double_split(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, |
|
int data_size) |
|
{ |
|
int ret; |
|
int progress = 0; |
|
int slot; |
|
u32 nritems; |
|
int space_needed = data_size; |
|
|
|
slot = path->slots[0]; |
|
if (slot < btrfs_header_nritems(path->nodes[0])) |
|
space_needed -= btrfs_leaf_free_space(path->nodes[0]); |
|
|
|
/* |
|
* try to push all the items after our slot into the |
|
* right leaf |
|
*/ |
|
ret = push_leaf_right(trans, root, path, 1, space_needed, 0, slot); |
|
if (ret < 0) |
|
return ret; |
|
|
|
if (ret == 0) |
|
progress++; |
|
|
|
nritems = btrfs_header_nritems(path->nodes[0]); |
|
/* |
|
* our goal is to get our slot at the start or end of a leaf. If |
|
* we've done so we're done |
|
*/ |
|
if (path->slots[0] == 0 || path->slots[0] == nritems) |
|
return 0; |
|
|
|
if (btrfs_leaf_free_space(path->nodes[0]) >= data_size) |
|
return 0; |
|
|
|
/* try to push all the items before our slot into the next leaf */ |
|
slot = path->slots[0]; |
|
space_needed = data_size; |
|
if (slot > 0) |
|
space_needed -= btrfs_leaf_free_space(path->nodes[0]); |
|
ret = push_leaf_left(trans, root, path, 1, space_needed, 0, slot); |
|
if (ret < 0) |
|
return ret; |
|
|
|
if (ret == 0) |
|
progress++; |
|
|
|
if (progress) |
|
return 0; |
|
return 1; |
|
} |
|
|
|
/* |
|
* split the path's leaf in two, making sure there is at least data_size |
|
* available for the resulting leaf level of the path. |
|
* |
|
* returns 0 if all went well and < 0 on failure. |
|
*/ |
|
static noinline int split_leaf(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
const struct btrfs_key *ins_key, |
|
struct btrfs_path *path, int data_size, |
|
int extend) |
|
{ |
|
struct btrfs_disk_key disk_key; |
|
struct extent_buffer *l; |
|
u32 nritems; |
|
int mid; |
|
int slot; |
|
struct extent_buffer *right; |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
int ret = 0; |
|
int wret; |
|
int split; |
|
int num_doubles = 0; |
|
int tried_avoid_double = 0; |
|
|
|
l = path->nodes[0]; |
|
slot = path->slots[0]; |
|
if (extend && data_size + btrfs_item_size_nr(l, slot) + |
|
sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(fs_info)) |
|
return -EOVERFLOW; |
|
|
|
/* first try to make some room by pushing left and right */ |
|
if (data_size && path->nodes[1]) { |
|
int space_needed = data_size; |
|
|
|
if (slot < btrfs_header_nritems(l)) |
|
space_needed -= btrfs_leaf_free_space(l); |
|
|
|
wret = push_leaf_right(trans, root, path, space_needed, |
|
space_needed, 0, 0); |
|
if (wret < 0) |
|
return wret; |
|
if (wret) { |
|
space_needed = data_size; |
|
if (slot > 0) |
|
space_needed -= btrfs_leaf_free_space(l); |
|
wret = push_leaf_left(trans, root, path, space_needed, |
|
space_needed, 0, (u32)-1); |
|
if (wret < 0) |
|
return wret; |
|
} |
|
l = path->nodes[0]; |
|
|
|
/* did the pushes work? */ |
|
if (btrfs_leaf_free_space(l) >= data_size) |
|
return 0; |
|
} |
|
|
|
if (!path->nodes[1]) { |
|
ret = insert_new_root(trans, root, path, 1); |
|
if (ret) |
|
return ret; |
|
} |
|
again: |
|
split = 1; |
|
l = path->nodes[0]; |
|
slot = path->slots[0]; |
|
nritems = btrfs_header_nritems(l); |
|
mid = (nritems + 1) / 2; |
|
|
|
if (mid <= slot) { |
|
if (nritems == 1 || |
|
leaf_space_used(l, mid, nritems - mid) + data_size > |
|
BTRFS_LEAF_DATA_SIZE(fs_info)) { |
|
if (slot >= nritems) { |
|
split = 0; |
|
} else { |
|
mid = slot; |
|
if (mid != nritems && |
|
leaf_space_used(l, mid, nritems - mid) + |
|
data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) { |
|
if (data_size && !tried_avoid_double) |
|
goto push_for_double; |
|
split = 2; |
|
} |
|
} |
|
} |
|
} else { |
|
if (leaf_space_used(l, 0, mid) + data_size > |
|
BTRFS_LEAF_DATA_SIZE(fs_info)) { |
|
if (!extend && data_size && slot == 0) { |
|
split = 0; |
|
} else if ((extend || !data_size) && slot == 0) { |
|
mid = 1; |
|
} else { |
|
mid = slot; |
|
if (mid != nritems && |
|
leaf_space_used(l, mid, nritems - mid) + |
|
data_size > BTRFS_LEAF_DATA_SIZE(fs_info)) { |
|
if (data_size && !tried_avoid_double) |
|
goto push_for_double; |
|
split = 2; |
|
} |
|
} |
|
} |
|
} |
|
|
|
if (split == 0) |
|
btrfs_cpu_key_to_disk(&disk_key, ins_key); |
|
else |
|
btrfs_item_key(l, &disk_key, mid); |
|
|
|
/* |
|
* We have to about BTRFS_NESTING_NEW_ROOT here if we've done a double |
|
* split, because we're only allowed to have MAX_LOCKDEP_SUBCLASSES |
|
* subclasses, which is 8 at the time of this patch, and we've maxed it |
|
* out. In the future we could add a |
|
* BTRFS_NESTING_SPLIT_THE_SPLITTENING if we need to, but for now just |
|
* use BTRFS_NESTING_NEW_ROOT. |
|
*/ |
|
right = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid, |
|
&disk_key, 0, l->start, 0, |
|
num_doubles ? BTRFS_NESTING_NEW_ROOT : |
|
BTRFS_NESTING_SPLIT); |
|
if (IS_ERR(right)) |
|
return PTR_ERR(right); |
|
|
|
root_add_used(root, fs_info->nodesize); |
|
|
|
if (split == 0) { |
|
if (mid <= slot) { |
|
btrfs_set_header_nritems(right, 0); |
|
insert_ptr(trans, path, &disk_key, |
|
right->start, path->slots[1] + 1, 1); |
|
btrfs_tree_unlock(path->nodes[0]); |
|
free_extent_buffer(path->nodes[0]); |
|
path->nodes[0] = right; |
|
path->slots[0] = 0; |
|
path->slots[1] += 1; |
|
} else { |
|
btrfs_set_header_nritems(right, 0); |
|
insert_ptr(trans, path, &disk_key, |
|
right->start, path->slots[1], 1); |
|
btrfs_tree_unlock(path->nodes[0]); |
|
free_extent_buffer(path->nodes[0]); |
|
path->nodes[0] = right; |
|
path->slots[0] = 0; |
|
if (path->slots[1] == 0) |
|
fixup_low_keys(path, &disk_key, 1); |
|
} |
|
/* |
|
* We create a new leaf 'right' for the required ins_len and |
|
* we'll do btrfs_mark_buffer_dirty() on this leaf after copying |
|
* the content of ins_len to 'right'. |
|
*/ |
|
return ret; |
|
} |
|
|
|
copy_for_split(trans, path, l, right, slot, mid, nritems); |
|
|
|
if (split == 2) { |
|
BUG_ON(num_doubles != 0); |
|
num_doubles++; |
|
goto again; |
|
} |
|
|
|
return 0; |
|
|
|
push_for_double: |
|
push_for_double_split(trans, root, path, data_size); |
|
tried_avoid_double = 1; |
|
if (btrfs_leaf_free_space(path->nodes[0]) >= data_size) |
|
return 0; |
|
goto again; |
|
} |
|
|
|
static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, int ins_len) |
|
{ |
|
struct btrfs_key key; |
|
struct extent_buffer *leaf; |
|
struct btrfs_file_extent_item *fi; |
|
u64 extent_len = 0; |
|
u32 item_size; |
|
int ret; |
|
|
|
leaf = path->nodes[0]; |
|
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); |
|
|
|
BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY && |
|
key.type != BTRFS_EXTENT_CSUM_KEY); |
|
|
|
if (btrfs_leaf_free_space(leaf) >= ins_len) |
|
return 0; |
|
|
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]); |
|
if (key.type == BTRFS_EXTENT_DATA_KEY) { |
|
fi = btrfs_item_ptr(leaf, path->slots[0], |
|
struct btrfs_file_extent_item); |
|
extent_len = btrfs_file_extent_num_bytes(leaf, fi); |
|
} |
|
btrfs_release_path(path); |
|
|
|
path->keep_locks = 1; |
|
path->search_for_split = 1; |
|
ret = btrfs_search_slot(trans, root, &key, path, 0, 1); |
|
path->search_for_split = 0; |
|
if (ret > 0) |
|
ret = -EAGAIN; |
|
if (ret < 0) |
|
goto err; |
|
|
|
ret = -EAGAIN; |
|
leaf = path->nodes[0]; |
|
/* if our item isn't there, return now */ |
|
if (item_size != btrfs_item_size_nr(leaf, path->slots[0])) |
|
goto err; |
|
|
|
/* the leaf has changed, it now has room. return now */ |
|
if (btrfs_leaf_free_space(path->nodes[0]) >= ins_len) |
|
goto err; |
|
|
|
if (key.type == BTRFS_EXTENT_DATA_KEY) { |
|
fi = btrfs_item_ptr(leaf, path->slots[0], |
|
struct btrfs_file_extent_item); |
|
if (extent_len != btrfs_file_extent_num_bytes(leaf, fi)) |
|
goto err; |
|
} |
|
|
|
ret = split_leaf(trans, root, &key, path, ins_len, 1); |
|
if (ret) |
|
goto err; |
|
|
|
path->keep_locks = 0; |
|
btrfs_unlock_up_safe(path, 1); |
|
return 0; |
|
err: |
|
path->keep_locks = 0; |
|
return ret; |
|
} |
|
|
|
static noinline int split_item(struct btrfs_path *path, |
|
const struct btrfs_key *new_key, |
|
unsigned long split_offset) |
|
{ |
|
struct extent_buffer *leaf; |
|
struct btrfs_item *item; |
|
struct btrfs_item *new_item; |
|
int slot; |
|
char *buf; |
|
u32 nritems; |
|
u32 item_size; |
|
u32 orig_offset; |
|
struct btrfs_disk_key disk_key; |
|
|
|
leaf = path->nodes[0]; |
|
BUG_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item)); |
|
|
|
item = btrfs_item_nr(path->slots[0]); |
|
orig_offset = btrfs_item_offset(leaf, item); |
|
item_size = btrfs_item_size(leaf, item); |
|
|
|
buf = kmalloc(item_size, GFP_NOFS); |
|
if (!buf) |
|
return -ENOMEM; |
|
|
|
read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, |
|
path->slots[0]), item_size); |
|
|
|
slot = path->slots[0] + 1; |
|
nritems = btrfs_header_nritems(leaf); |
|
if (slot != nritems) { |
|
/* shift the items */ |
|
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1), |
|
btrfs_item_nr_offset(slot), |
|
(nritems - slot) * sizeof(struct btrfs_item)); |
|
} |
|
|
|
btrfs_cpu_key_to_disk(&disk_key, new_key); |
|
btrfs_set_item_key(leaf, &disk_key, slot); |
|
|
|
new_item = btrfs_item_nr(slot); |
|
|
|
btrfs_set_item_offset(leaf, new_item, orig_offset); |
|
btrfs_set_item_size(leaf, new_item, item_size - split_offset); |
|
|
|
btrfs_set_item_offset(leaf, item, |
|
orig_offset + item_size - split_offset); |
|
btrfs_set_item_size(leaf, item, split_offset); |
|
|
|
btrfs_set_header_nritems(leaf, nritems + 1); |
|
|
|
/* write the data for the start of the original item */ |
|
write_extent_buffer(leaf, buf, |
|
btrfs_item_ptr_offset(leaf, path->slots[0]), |
|
split_offset); |
|
|
|
/* write the data for the new item */ |
|
write_extent_buffer(leaf, buf + split_offset, |
|
btrfs_item_ptr_offset(leaf, slot), |
|
item_size - split_offset); |
|
btrfs_mark_buffer_dirty(leaf); |
|
|
|
BUG_ON(btrfs_leaf_free_space(leaf) < 0); |
|
kfree(buf); |
|
return 0; |
|
} |
|
|
|
/* |
|
* This function splits a single item into two items, |
|
* giving 'new_key' to the new item and splitting the |
|
* old one at split_offset (from the start of the item). |
|
* |
|
* The path may be released by this operation. After |
|
* the split, the path is pointing to the old item. The |
|
* new item is going to be in the same node as the old one. |
|
* |
|
* Note, the item being split must be smaller enough to live alone on |
|
* a tree block with room for one extra struct btrfs_item |
|
* |
|
* This allows us to split the item in place, keeping a lock on the |
|
* leaf the entire time. |
|
*/ |
|
int btrfs_split_item(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, |
|
const struct btrfs_key *new_key, |
|
unsigned long split_offset) |
|
{ |
|
int ret; |
|
ret = setup_leaf_for_split(trans, root, path, |
|
sizeof(struct btrfs_item)); |
|
if (ret) |
|
return ret; |
|
|
|
ret = split_item(path, new_key, split_offset); |
|
return ret; |
|
} |
|
|
|
/* |
|
* This function duplicate a item, giving 'new_key' to the new item. |
|
* It guarantees both items live in the same tree leaf and the new item |
|
* is contiguous with the original item. |
|
* |
|
* This allows us to split file extent in place, keeping a lock on the |
|
* leaf the entire time. |
|
*/ |
|
int btrfs_duplicate_item(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, |
|
const struct btrfs_key *new_key) |
|
{ |
|
struct extent_buffer *leaf; |
|
int ret; |
|
u32 item_size; |
|
|
|
leaf = path->nodes[0]; |
|
item_size = btrfs_item_size_nr(leaf, path->slots[0]); |
|
ret = setup_leaf_for_split(trans, root, path, |
|
item_size + sizeof(struct btrfs_item)); |
|
if (ret) |
|
return ret; |
|
|
|
path->slots[0]++; |
|
setup_items_for_insert(root, path, new_key, &item_size, 1); |
|
leaf = path->nodes[0]; |
|
memcpy_extent_buffer(leaf, |
|
btrfs_item_ptr_offset(leaf, path->slots[0]), |
|
btrfs_item_ptr_offset(leaf, path->slots[0] - 1), |
|
item_size); |
|
return 0; |
|
} |
|
|
|
/* |
|
* make the item pointed to by the path smaller. new_size indicates |
|
* how small to make it, and from_end tells us if we just chop bytes |
|
* off the end of the item or if we shift the item to chop bytes off |
|
* the front. |
|
*/ |
|
void btrfs_truncate_item(struct btrfs_path *path, u32 new_size, int from_end) |
|
{ |
|
int slot; |
|
struct extent_buffer *leaf; |
|
struct btrfs_item *item; |
|
u32 nritems; |
|
unsigned int data_end; |
|
unsigned int old_data_start; |
|
unsigned int old_size; |
|
unsigned int size_diff; |
|
int i; |
|
struct btrfs_map_token token; |
|
|
|
leaf = path->nodes[0]; |
|
slot = path->slots[0]; |
|
|
|
old_size = btrfs_item_size_nr(leaf, slot); |
|
if (old_size == new_size) |
|
return; |
|
|
|
nritems = btrfs_header_nritems(leaf); |
|
data_end = leaf_data_end(leaf); |
|
|
|
old_data_start = btrfs_item_offset_nr(leaf, slot); |
|
|
|
size_diff = old_size - new_size; |
|
|
|
BUG_ON(slot < 0); |
|
BUG_ON(slot >= nritems); |
|
|
|
/* |
|
* item0..itemN ... dataN.offset..dataN.size .. data0.size |
|
*/ |
|
/* first correct the data pointers */ |
|
btrfs_init_map_token(&token, leaf); |
|
for (i = slot; i < nritems; i++) { |
|
u32 ioff; |
|
item = btrfs_item_nr(i); |
|
|
|
ioff = btrfs_token_item_offset(&token, item); |
|
btrfs_set_token_item_offset(&token, item, ioff + size_diff); |
|
} |
|
|
|
/* shift the data */ |
|
if (from_end) { |
|
memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
|
data_end + size_diff, BTRFS_LEAF_DATA_OFFSET + |
|
data_end, old_data_start + new_size - data_end); |
|
} else { |
|
struct btrfs_disk_key disk_key; |
|
u64 offset; |
|
|
|
btrfs_item_key(leaf, &disk_key, slot); |
|
|
|
if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) { |
|
unsigned long ptr; |
|
struct btrfs_file_extent_item *fi; |
|
|
|
fi = btrfs_item_ptr(leaf, slot, |
|
struct btrfs_file_extent_item); |
|
fi = (struct btrfs_file_extent_item *)( |
|
(unsigned long)fi - size_diff); |
|
|
|
if (btrfs_file_extent_type(leaf, fi) == |
|
BTRFS_FILE_EXTENT_INLINE) { |
|
ptr = btrfs_item_ptr_offset(leaf, slot); |
|
memmove_extent_buffer(leaf, ptr, |
|
(unsigned long)fi, |
|
BTRFS_FILE_EXTENT_INLINE_DATA_START); |
|
} |
|
} |
|
|
|
memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
|
data_end + size_diff, BTRFS_LEAF_DATA_OFFSET + |
|
data_end, old_data_start - data_end); |
|
|
|
offset = btrfs_disk_key_offset(&disk_key); |
|
btrfs_set_disk_key_offset(&disk_key, offset + size_diff); |
|
btrfs_set_item_key(leaf, &disk_key, slot); |
|
if (slot == 0) |
|
fixup_low_keys(path, &disk_key, 1); |
|
} |
|
|
|
item = btrfs_item_nr(slot); |
|
btrfs_set_item_size(leaf, item, new_size); |
|
btrfs_mark_buffer_dirty(leaf); |
|
|
|
if (btrfs_leaf_free_space(leaf) < 0) { |
|
btrfs_print_leaf(leaf); |
|
BUG(); |
|
} |
|
} |
|
|
|
/* |
|
* make the item pointed to by the path bigger, data_size is the added size. |
|
*/ |
|
void btrfs_extend_item(struct btrfs_path *path, u32 data_size) |
|
{ |
|
int slot; |
|
struct extent_buffer *leaf; |
|
struct btrfs_item *item; |
|
u32 nritems; |
|
unsigned int data_end; |
|
unsigned int old_data; |
|
unsigned int old_size; |
|
int i; |
|
struct btrfs_map_token token; |
|
|
|
leaf = path->nodes[0]; |
|
|
|
nritems = btrfs_header_nritems(leaf); |
|
data_end = leaf_data_end(leaf); |
|
|
|
if (btrfs_leaf_free_space(leaf) < data_size) { |
|
btrfs_print_leaf(leaf); |
|
BUG(); |
|
} |
|
slot = path->slots[0]; |
|
old_data = btrfs_item_end_nr(leaf, slot); |
|
|
|
BUG_ON(slot < 0); |
|
if (slot >= nritems) { |
|
btrfs_print_leaf(leaf); |
|
btrfs_crit(leaf->fs_info, "slot %d too large, nritems %d", |
|
slot, nritems); |
|
BUG(); |
|
} |
|
|
|
/* |
|
* item0..itemN ... dataN.offset..dataN.size .. data0.size |
|
*/ |
|
/* first correct the data pointers */ |
|
btrfs_init_map_token(&token, leaf); |
|
for (i = slot; i < nritems; i++) { |
|
u32 ioff; |
|
item = btrfs_item_nr(i); |
|
|
|
ioff = btrfs_token_item_offset(&token, item); |
|
btrfs_set_token_item_offset(&token, item, ioff - data_size); |
|
} |
|
|
|
/* shift the data */ |
|
memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
|
data_end - data_size, BTRFS_LEAF_DATA_OFFSET + |
|
data_end, old_data - data_end); |
|
|
|
data_end = old_data; |
|
old_size = btrfs_item_size_nr(leaf, slot); |
|
item = btrfs_item_nr(slot); |
|
btrfs_set_item_size(leaf, item, old_size + data_size); |
|
btrfs_mark_buffer_dirty(leaf); |
|
|
|
if (btrfs_leaf_free_space(leaf) < 0) { |
|
btrfs_print_leaf(leaf); |
|
BUG(); |
|
} |
|
} |
|
|
|
/** |
|
* setup_items_for_insert - Helper called before inserting one or more items |
|
* to a leaf. Main purpose is to save stack depth by doing the bulk of the work |
|
* in a function that doesn't call btrfs_search_slot |
|
* |
|
* @root: root we are inserting items to |
|
* @path: points to the leaf/slot where we are going to insert new items |
|
* @cpu_key: array of keys for items to be inserted |
|
* @data_size: size of the body of each item we are going to insert |
|
* @nr: size of @cpu_key/@data_size arrays |
|
*/ |
|
void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path, |
|
const struct btrfs_key *cpu_key, u32 *data_size, |
|
int nr) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
struct btrfs_item *item; |
|
int i; |
|
u32 nritems; |
|
unsigned int data_end; |
|
struct btrfs_disk_key disk_key; |
|
struct extent_buffer *leaf; |
|
int slot; |
|
struct btrfs_map_token token; |
|
u32 total_size; |
|
u32 total_data = 0; |
|
|
|
for (i = 0; i < nr; i++) |
|
total_data += data_size[i]; |
|
total_size = total_data + (nr * sizeof(struct btrfs_item)); |
|
|
|
if (path->slots[0] == 0) { |
|
btrfs_cpu_key_to_disk(&disk_key, cpu_key); |
|
fixup_low_keys(path, &disk_key, 1); |
|
} |
|
btrfs_unlock_up_safe(path, 1); |
|
|
|
leaf = path->nodes[0]; |
|
slot = path->slots[0]; |
|
|
|
nritems = btrfs_header_nritems(leaf); |
|
data_end = leaf_data_end(leaf); |
|
|
|
if (btrfs_leaf_free_space(leaf) < total_size) { |
|
btrfs_print_leaf(leaf); |
|
btrfs_crit(fs_info, "not enough freespace need %u have %d", |
|
total_size, btrfs_leaf_free_space(leaf)); |
|
BUG(); |
|
} |
|
|
|
btrfs_init_map_token(&token, leaf); |
|
if (slot != nritems) { |
|
unsigned int old_data = btrfs_item_end_nr(leaf, slot); |
|
|
|
if (old_data < data_end) { |
|
btrfs_print_leaf(leaf); |
|
btrfs_crit(fs_info, |
|
"item at slot %d with data offset %u beyond data end of leaf %u", |
|
slot, old_data, data_end); |
|
BUG(); |
|
} |
|
/* |
|
* item0..itemN ... dataN.offset..dataN.size .. data0.size |
|
*/ |
|
/* first correct the data pointers */ |
|
for (i = slot; i < nritems; i++) { |
|
u32 ioff; |
|
|
|
item = btrfs_item_nr(i); |
|
ioff = btrfs_token_item_offset(&token, item); |
|
btrfs_set_token_item_offset(&token, item, |
|
ioff - total_data); |
|
} |
|
/* shift the items */ |
|
memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr), |
|
btrfs_item_nr_offset(slot), |
|
(nritems - slot) * sizeof(struct btrfs_item)); |
|
|
|
/* shift the data */ |
|
memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
|
data_end - total_data, BTRFS_LEAF_DATA_OFFSET + |
|
data_end, old_data - data_end); |
|
data_end = old_data; |
|
} |
|
|
|
/* setup the item for the new data */ |
|
for (i = 0; i < nr; i++) { |
|
btrfs_cpu_key_to_disk(&disk_key, cpu_key + i); |
|
btrfs_set_item_key(leaf, &disk_key, slot + i); |
|
item = btrfs_item_nr(slot + i); |
|
data_end -= data_size[i]; |
|
btrfs_set_token_item_offset(&token, item, data_end); |
|
btrfs_set_token_item_size(&token, item, data_size[i]); |
|
} |
|
|
|
btrfs_set_header_nritems(leaf, nritems + nr); |
|
btrfs_mark_buffer_dirty(leaf); |
|
|
|
if (btrfs_leaf_free_space(leaf) < 0) { |
|
btrfs_print_leaf(leaf); |
|
BUG(); |
|
} |
|
} |
|
|
|
/* |
|
* Given a key and some data, insert items into the tree. |
|
* This does all the path init required, making room in the tree if needed. |
|
*/ |
|
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, |
|
const struct btrfs_key *cpu_key, u32 *data_size, |
|
int nr) |
|
{ |
|
int ret = 0; |
|
int slot; |
|
int i; |
|
u32 total_size = 0; |
|
u32 total_data = 0; |
|
|
|
for (i = 0; i < nr; i++) |
|
total_data += data_size[i]; |
|
|
|
total_size = total_data + (nr * sizeof(struct btrfs_item)); |
|
ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1); |
|
if (ret == 0) |
|
return -EEXIST; |
|
if (ret < 0) |
|
return ret; |
|
|
|
slot = path->slots[0]; |
|
BUG_ON(slot < 0); |
|
|
|
setup_items_for_insert(root, path, cpu_key, data_size, nr); |
|
return 0; |
|
} |
|
|
|
/* |
|
* Given a key and some data, insert an item into the tree. |
|
* This does all the path init required, making room in the tree if needed. |
|
*/ |
|
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
|
const struct btrfs_key *cpu_key, void *data, |
|
u32 data_size) |
|
{ |
|
int ret = 0; |
|
struct btrfs_path *path; |
|
struct extent_buffer *leaf; |
|
unsigned long ptr; |
|
|
|
path = btrfs_alloc_path(); |
|
if (!path) |
|
return -ENOMEM; |
|
ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size); |
|
if (!ret) { |
|
leaf = path->nodes[0]; |
|
ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); |
|
write_extent_buffer(leaf, data, ptr, data_size); |
|
btrfs_mark_buffer_dirty(leaf); |
|
} |
|
btrfs_free_path(path); |
|
return ret; |
|
} |
|
|
|
/* |
|
* delete the pointer from a given node. |
|
* |
|
* the tree should have been previously balanced so the deletion does not |
|
* empty a node. |
|
*/ |
|
static void del_ptr(struct btrfs_root *root, struct btrfs_path *path, |
|
int level, int slot) |
|
{ |
|
struct extent_buffer *parent = path->nodes[level]; |
|
u32 nritems; |
|
int ret; |
|
|
|
nritems = btrfs_header_nritems(parent); |
|
if (slot != nritems - 1) { |
|
if (level) { |
|
ret = btrfs_tree_mod_log_insert_move(parent, slot, |
|
slot + 1, nritems - slot - 1); |
|
BUG_ON(ret < 0); |
|
} |
|
memmove_extent_buffer(parent, |
|
btrfs_node_key_ptr_offset(slot), |
|
btrfs_node_key_ptr_offset(slot + 1), |
|
sizeof(struct btrfs_key_ptr) * |
|
(nritems - slot - 1)); |
|
} else if (level) { |
|
ret = btrfs_tree_mod_log_insert_key(parent, slot, |
|
BTRFS_MOD_LOG_KEY_REMOVE, GFP_NOFS); |
|
BUG_ON(ret < 0); |
|
} |
|
|
|
nritems--; |
|
btrfs_set_header_nritems(parent, nritems); |
|
if (nritems == 0 && parent == root->node) { |
|
BUG_ON(btrfs_header_level(root->node) != 1); |
|
/* just turn the root into a leaf and break */ |
|
btrfs_set_header_level(root->node, 0); |
|
} else if (slot == 0) { |
|
struct btrfs_disk_key disk_key; |
|
|
|
btrfs_node_key(parent, &disk_key, 0); |
|
fixup_low_keys(path, &disk_key, level + 1); |
|
} |
|
btrfs_mark_buffer_dirty(parent); |
|
} |
|
|
|
/* |
|
* a helper function to delete the leaf pointed to by path->slots[1] and |
|
* path->nodes[1]. |
|
* |
|
* This deletes the pointer in path->nodes[1] and frees the leaf |
|
* block extent. zero is returned if it all worked out, < 0 otherwise. |
|
* |
|
* The path must have already been setup for deleting the leaf, including |
|
* all the proper balancing. path->nodes[1] must be locked. |
|
*/ |
|
static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans, |
|
struct btrfs_root *root, |
|
struct btrfs_path *path, |
|
struct extent_buffer *leaf) |
|
{ |
|
WARN_ON(btrfs_header_generation(leaf) != trans->transid); |
|
del_ptr(root, path, 1, path->slots[1]); |
|
|
|
/* |
|
* btrfs_free_extent is expensive, we want to make sure we |
|
* aren't holding any locks when we call it |
|
*/ |
|
btrfs_unlock_up_safe(path, 0); |
|
|
|
root_sub_used(root, leaf->len); |
|
|
|
atomic_inc(&leaf->refs); |
|
btrfs_free_tree_block(trans, root, leaf, 0, 1); |
|
free_extent_buffer_stale(leaf); |
|
} |
|
/* |
|
* delete the item at the leaf level in path. If that empties |
|
* the leaf, remove it from the tree |
|
*/ |
|
int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root, |
|
struct btrfs_path *path, int slot, int nr) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
struct extent_buffer *leaf; |
|
struct btrfs_item *item; |
|
u32 last_off; |
|
u32 dsize = 0; |
|
int ret = 0; |
|
int wret; |
|
int i; |
|
u32 nritems; |
|
|
|
leaf = path->nodes[0]; |
|
last_off = btrfs_item_offset_nr(leaf, slot + nr - 1); |
|
|
|
for (i = 0; i < nr; i++) |
|
dsize += btrfs_item_size_nr(leaf, slot + i); |
|
|
|
nritems = btrfs_header_nritems(leaf); |
|
|
|
if (slot + nr != nritems) { |
|
int data_end = leaf_data_end(leaf); |
|
struct btrfs_map_token token; |
|
|
|
memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET + |
|
data_end + dsize, |
|
BTRFS_LEAF_DATA_OFFSET + data_end, |
|
last_off - data_end); |
|
|
|
btrfs_init_map_token(&token, leaf); |
|
for (i = slot + nr; i < nritems; i++) { |
|
u32 ioff; |
|
|
|
item = btrfs_item_nr(i); |
|
ioff = btrfs_token_item_offset(&token, item); |
|
btrfs_set_token_item_offset(&token, item, ioff + dsize); |
|
} |
|
|
|
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_clean_tree_block(leaf); |
|
btrfs_del_leaf(trans, root, path, leaf); |
|
} |
|
} else { |
|
int used = leaf_space_used(leaf, 0, nritems); |
|
if (slot == 0) { |
|
struct btrfs_disk_key disk_key; |
|
|
|
btrfs_item_key(leaf, &disk_key, 0); |
|
fixup_low_keys(path, &disk_key, 1); |
|
} |
|
|
|
/* delete the leaf if it is mostly empty */ |
|
if (used < BTRFS_LEAF_DATA_SIZE(fs_info) / 3) { |
|
/* push_leaf_left fixes the path. |
|
* make sure the path still points to our leaf |
|
* for possible call to del_ptr below |
|
*/ |
|
slot = path->slots[1]; |
|
atomic_inc(&leaf->refs); |
|
|
|
wret = push_leaf_left(trans, root, path, 1, 1, |
|
1, (u32)-1); |
|
if (wret < 0 && wret != -ENOSPC) |
|
ret = wret; |
|
|
|
if (path->nodes[0] == leaf && |
|
btrfs_header_nritems(leaf)) { |
|
wret = push_leaf_right(trans, root, path, 1, |
|
1, 1, 0); |
|
if (wret < 0 && wret != -ENOSPC) |
|
ret = wret; |
|
} |
|
|
|
if (btrfs_header_nritems(leaf) == 0) { |
|
path->slots[1] = slot; |
|
btrfs_del_leaf(trans, root, path, leaf); |
|
free_extent_buffer(leaf); |
|
ret = 0; |
|
} else { |
|
/* if we're still in the path, make sure |
|
* we're dirty. Otherwise, one of the |
|
* push_leaf functions must have already |
|
* dirtied this buffer |
|
*/ |
|
if (path->nodes[0] == leaf) |
|
btrfs_mark_buffer_dirty(leaf); |
|
free_extent_buffer(leaf); |
|
} |
|
} else { |
|
btrfs_mark_buffer_dirty(leaf); |
|
} |
|
} |
|
return ret; |
|
} |
|
|
|
/* |
|
* search the tree again to find a leaf with lesser keys |
|
* returns 0 if it found something or 1 if there are no lesser leaves. |
|
* returns < 0 on io errors. |
|
* |
|
* This may release the path, and so you may lose any locks held at the |
|
* time you call it. |
|
*/ |
|
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) |
|
{ |
|
struct btrfs_key key; |
|
struct btrfs_disk_key found_key; |
|
int ret; |
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, 0); |
|
|
|
if (key.offset > 0) { |
|
key.offset--; |
|
} else if (key.type > 0) { |
|
key.type--; |
|
key.offset = (u64)-1; |
|
} else if (key.objectid > 0) { |
|
key.objectid--; |
|
key.type = (u8)-1; |
|
key.offset = (u64)-1; |
|
} else { |
|
return 1; |
|
} |
|
|
|
btrfs_release_path(path); |
|
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
|
if (ret < 0) |
|
return ret; |
|
btrfs_item_key(path->nodes[0], &found_key, 0); |
|
ret = comp_keys(&found_key, &key); |
|
/* |
|
* We might have had an item with the previous key in the tree right |
|
* before we released our path. And after we released our path, that |
|
* item might have been pushed to the first slot (0) of the leaf we |
|
* were holding due to a tree balance. Alternatively, an item with the |
|
* previous key can exist as the only element of a leaf (big fat item). |
|
* Therefore account for these 2 cases, so that our callers (like |
|
* btrfs_previous_item) don't miss an existing item with a key matching |
|
* the previous key we computed above. |
|
*/ |
|
if (ret <= 0) |
|
return 0; |
|
return 1; |
|
} |
|
|
|
/* |
|
* A helper function to walk down the tree starting at min_key, and looking |
|
* for nodes or leaves that are have a minimum transaction id. |
|
* This is used by the btree defrag code, and tree logging |
|
* |
|
* This does not cow, but it does stuff the starting key it finds back |
|
* into min_key, so you can call btrfs_search_slot with cow=1 on the |
|
* key and get a writable path. |
|
* |
|
* This honors path->lowest_level to prevent descent past a given level |
|
* of the tree. |
|
* |
|
* min_trans indicates the oldest transaction that you are interested |
|
* in walking through. Any nodes or leaves older than min_trans are |
|
* skipped over (without reading them). |
|
* |
|
* returns zero if something useful was found, < 0 on error and 1 if there |
|
* was nothing in the tree that matched the search criteria. |
|
*/ |
|
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key, |
|
struct btrfs_path *path, |
|
u64 min_trans) |
|
{ |
|
struct extent_buffer *cur; |
|
struct btrfs_key found_key; |
|
int slot; |
|
int sret; |
|
u32 nritems; |
|
int level; |
|
int ret = 1; |
|
int keep_locks = path->keep_locks; |
|
|
|
path->keep_locks = 1; |
|
again: |
|
cur = btrfs_read_lock_root_node(root); |
|
level = btrfs_header_level(cur); |
|
WARN_ON(path->nodes[level]); |
|
path->nodes[level] = cur; |
|
path->locks[level] = BTRFS_READ_LOCK; |
|
|
|
if (btrfs_header_generation(cur) < min_trans) { |
|
ret = 1; |
|
goto out; |
|
} |
|
while (1) { |
|
nritems = btrfs_header_nritems(cur); |
|
level = btrfs_header_level(cur); |
|
sret = btrfs_bin_search(cur, min_key, &slot); |
|
if (sret < 0) { |
|
ret = sret; |
|
goto out; |
|
} |
|
|
|
/* at the lowest level, we're done, setup the path and exit */ |
|
if (level == path->lowest_level) { |
|
if (slot >= nritems) |
|
goto find_next_key; |
|
ret = 0; |
|
path->slots[level] = slot; |
|
btrfs_item_key_to_cpu(cur, &found_key, slot); |
|
goto out; |
|
} |
|
if (sret && slot > 0) |
|
slot--; |
|
/* |
|
* check this node pointer against the min_trans parameters. |
|
* If it is too old, skip to the next one. |
|
*/ |
|
while (slot < nritems) { |
|
u64 gen; |
|
|
|
gen = btrfs_node_ptr_generation(cur, slot); |
|
if (gen < min_trans) { |
|
slot++; |
|
continue; |
|
} |
|
break; |
|
} |
|
find_next_key: |
|
/* |
|
* we didn't find a candidate key in this node, walk forward |
|
* and find another one |
|
*/ |
|
if (slot >= nritems) { |
|
path->slots[level] = slot; |
|
sret = btrfs_find_next_key(root, path, min_key, level, |
|
min_trans); |
|
if (sret == 0) { |
|
btrfs_release_path(path); |
|
goto again; |
|
} else { |
|
goto out; |
|
} |
|
} |
|
/* save our key for returning back */ |
|
btrfs_node_key_to_cpu(cur, &found_key, slot); |
|
path->slots[level] = slot; |
|
if (level == path->lowest_level) { |
|
ret = 0; |
|
goto out; |
|
} |
|
cur = btrfs_read_node_slot(cur, slot); |
|
if (IS_ERR(cur)) { |
|
ret = PTR_ERR(cur); |
|
goto out; |
|
} |
|
|
|
btrfs_tree_read_lock(cur); |
|
|
|
path->locks[level - 1] = BTRFS_READ_LOCK; |
|
path->nodes[level - 1] = cur; |
|
unlock_up(path, level, 1, 0, NULL); |
|
} |
|
out: |
|
path->keep_locks = keep_locks; |
|
if (ret == 0) { |
|
btrfs_unlock_up_safe(path, path->lowest_level + 1); |
|
memcpy(min_key, &found_key, sizeof(found_key)); |
|
} |
|
return ret; |
|
} |
|
|
|
/* |
|
* this is similar to btrfs_next_leaf, but does not try to preserve |
|
* and fixup the path. It looks for and returns the next key in the |
|
* tree based on the current path and the min_trans parameters. |
|
* |
|
* 0 is returned if another key is found, < 0 if there are any errors |
|
* and 1 is returned if there are no higher keys in the tree |
|
* |
|
* path->keep_locks should be set to 1 on the search made before |
|
* calling this function. |
|
*/ |
|
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path, |
|
struct btrfs_key *key, int level, u64 min_trans) |
|
{ |
|
int slot; |
|
struct extent_buffer *c; |
|
|
|
WARN_ON(!path->keep_locks && !path->skip_locking); |
|
while (level < BTRFS_MAX_LEVEL) { |
|
if (!path->nodes[level]) |
|
return 1; |
|
|
|
slot = path->slots[level] + 1; |
|
c = path->nodes[level]; |
|
next: |
|
if (slot >= btrfs_header_nritems(c)) { |
|
int ret; |
|
int orig_lowest; |
|
struct btrfs_key cur_key; |
|
if (level + 1 >= BTRFS_MAX_LEVEL || |
|
!path->nodes[level + 1]) |
|
return 1; |
|
|
|
if (path->locks[level + 1] || path->skip_locking) { |
|
level++; |
|
continue; |
|
} |
|
|
|
slot = btrfs_header_nritems(c) - 1; |
|
if (level == 0) |
|
btrfs_item_key_to_cpu(c, &cur_key, slot); |
|
else |
|
btrfs_node_key_to_cpu(c, &cur_key, slot); |
|
|
|
orig_lowest = path->lowest_level; |
|
btrfs_release_path(path); |
|
path->lowest_level = level; |
|
ret = btrfs_search_slot(NULL, root, &cur_key, path, |
|
0, 0); |
|
path->lowest_level = orig_lowest; |
|
if (ret < 0) |
|
return ret; |
|
|
|
c = path->nodes[level]; |
|
slot = path->slots[level]; |
|
if (ret == 0) |
|
slot++; |
|
goto next; |
|
} |
|
|
|
if (level == 0) |
|
btrfs_item_key_to_cpu(c, key, slot); |
|
else { |
|
u64 gen = btrfs_node_ptr_generation(c, slot); |
|
|
|
if (gen < min_trans) { |
|
slot++; |
|
goto next; |
|
} |
|
btrfs_node_key_to_cpu(c, key, slot); |
|
} |
|
return 0; |
|
} |
|
return 1; |
|
} |
|
|
|
/* |
|
* 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 i; |
|
|
|
nritems = btrfs_header_nritems(path->nodes[0]); |
|
if (nritems == 0) |
|
return 1; |
|
|
|
btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1); |
|
again: |
|
level = 1; |
|
next = NULL; |
|
btrfs_release_path(path); |
|
|
|
path->keep_locks = 1; |
|
|
|
if (time_seq) |
|
ret = btrfs_search_old_slot(root, &key, path, time_seq); |
|
else |
|
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; |
|
} |
|
|
|
|
|
/* |
|
* Our current level is where we're going to start from, and to |
|
* make sure lockdep doesn't complain we need to drop our locks |
|
* and nodes from 0 to our current level. |
|
*/ |
|
for (i = 0; i < level; i++) { |
|
if (path->locks[level]) { |
|
btrfs_tree_read_unlock(path->nodes[i]); |
|
path->locks[i] = 0; |
|
} |
|
free_extent_buffer(path->nodes[i]); |
|
path->nodes[i] = NULL; |
|
} |
|
|
|
next = c; |
|
ret = read_block_for_search(root, path, &next, level, |
|
slot, &key); |
|
if (ret == -EAGAIN) |
|
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_tree_read_lock(next); |
|
} |
|
break; |
|
} |
|
path->slots[level] = slot; |
|
while (1) { |
|
level--; |
|
path->nodes[level] = next; |
|
path->slots[level] = 0; |
|
if (!path->skip_locking) |
|
path->locks[level] = BTRFS_READ_LOCK; |
|
if (!level) |
|
break; |
|
|
|
ret = read_block_for_search(root, path, &next, level, |
|
0, &key); |
|
if (ret == -EAGAIN) |
|
goto again; |
|
|
|
if (ret < 0) { |
|
btrfs_release_path(path); |
|
goto done; |
|
} |
|
|
|
if (!path->skip_locking) |
|
btrfs_tree_read_lock(next); |
|
} |
|
ret = 0; |
|
done: |
|
unlock_up(path, 0, 1, 0, NULL); |
|
|
|
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) { |
|
ret = btrfs_prev_leaf(root, path); |
|
if (ret != 0) |
|
return ret; |
|
} else { |
|
path->slots[0]--; |
|
} |
|
leaf = path->nodes[0]; |
|
nritems = btrfs_header_nritems(leaf); |
|
if (nritems == 0) |
|
return 1; |
|
if (path->slots[0] == nritems) |
|
path->slots[0]--; |
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); |
|
if (found_key.objectid < min_objectid) |
|
break; |
|
if (found_key.type == type) |
|
return 0; |
|
if (found_key.objectid == min_objectid && |
|
found_key.type < type) |
|
break; |
|
} |
|
return 1; |
|
} |
|
|
|
/* |
|
* search in extent tree to find a previous Metadata/Data extent item with |
|
* min objecitd. |
|
* |
|
* returns 0 if something is found, 1 if nothing was found and < 0 on error |
|
*/ |
|
int btrfs_previous_extent_item(struct btrfs_root *root, |
|
struct btrfs_path *path, u64 min_objectid) |
|
{ |
|
struct btrfs_key found_key; |
|
struct extent_buffer *leaf; |
|
u32 nritems; |
|
int ret; |
|
|
|
while (1) { |
|
if (path->slots[0] == 0) { |
|
ret = btrfs_prev_leaf(root, path); |
|
if (ret != 0) |
|
return ret; |
|
} else { |
|
path->slots[0]--; |
|
} |
|
leaf = path->nodes[0]; |
|
nritems = btrfs_header_nritems(leaf); |
|
if (nritems == 0) |
|
return 1; |
|
if (path->slots[0] == nritems) |
|
path->slots[0]--; |
|
|
|
btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); |
|
if (found_key.objectid < min_objectid) |
|
break; |
|
if (found_key.type == BTRFS_EXTENT_ITEM_KEY || |
|
found_key.type == BTRFS_METADATA_ITEM_KEY) |
|
return 0; |
|
if (found_key.objectid == min_objectid && |
|
found_key.type < BTRFS_EXTENT_ITEM_KEY) |
|
break; |
|
} |
|
return 1; |
|
}
|
|
|