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929 lines
24 KiB
929 lines
24 KiB
// SPDX-License-Identifier: GPL-2.0 |
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|
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#include "tree-mod-log.h" |
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#include "disk-io.h" |
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|
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struct tree_mod_root { |
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u64 logical; |
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u8 level; |
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}; |
|
|
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struct tree_mod_elem { |
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struct rb_node node; |
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u64 logical; |
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u64 seq; |
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enum btrfs_mod_log_op op; |
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|
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/* |
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* This is used for BTRFS_MOD_LOG_KEY_* and BTRFS_MOD_LOG_MOVE_KEYS |
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* operations. |
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*/ |
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int slot; |
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|
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/* This is used for BTRFS_MOD_LOG_KEY* and BTRFS_MOD_LOG_ROOT_REPLACE. */ |
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u64 generation; |
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|
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/* Those are used for op == BTRFS_MOD_LOG_KEY_{REPLACE,REMOVE}. */ |
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struct btrfs_disk_key key; |
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u64 blockptr; |
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|
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/* This is used for op == BTRFS_MOD_LOG_MOVE_KEYS. */ |
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struct { |
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int dst_slot; |
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int nr_items; |
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} move; |
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|
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/* This is used for op == BTRFS_MOD_LOG_ROOT_REPLACE. */ |
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struct tree_mod_root old_root; |
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}; |
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|
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/* |
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* Pull a new tree mod seq number for our operation. |
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*/ |
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static inline u64 btrfs_inc_tree_mod_seq(struct btrfs_fs_info *fs_info) |
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{ |
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return atomic64_inc_return(&fs_info->tree_mod_seq); |
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} |
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|
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/* |
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* This adds a new blocker to the tree mod log's blocker list if the @elem |
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* passed does not already have a sequence number set. So when a caller expects |
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* to record tree modifications, it should ensure to set elem->seq to zero |
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* before calling btrfs_get_tree_mod_seq. |
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* Returns a fresh, unused tree log modification sequence number, even if no new |
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* blocker was added. |
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*/ |
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u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info, |
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struct btrfs_seq_list *elem) |
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{ |
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write_lock(&fs_info->tree_mod_log_lock); |
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if (!elem->seq) { |
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elem->seq = btrfs_inc_tree_mod_seq(fs_info); |
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list_add_tail(&elem->list, &fs_info->tree_mod_seq_list); |
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set_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags); |
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} |
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write_unlock(&fs_info->tree_mod_log_lock); |
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|
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return elem->seq; |
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} |
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|
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void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info, |
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struct btrfs_seq_list *elem) |
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{ |
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struct rb_root *tm_root; |
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struct rb_node *node; |
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struct rb_node *next; |
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struct tree_mod_elem *tm; |
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u64 min_seq = BTRFS_SEQ_LAST; |
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u64 seq_putting = elem->seq; |
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|
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if (!seq_putting) |
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return; |
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|
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write_lock(&fs_info->tree_mod_log_lock); |
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list_del(&elem->list); |
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elem->seq = 0; |
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|
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if (list_empty(&fs_info->tree_mod_seq_list)) { |
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clear_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags); |
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} else { |
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struct btrfs_seq_list *first; |
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|
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first = list_first_entry(&fs_info->tree_mod_seq_list, |
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struct btrfs_seq_list, list); |
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if (seq_putting > first->seq) { |
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/* |
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* Blocker with lower sequence number exists, we cannot |
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* remove anything from the log. |
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*/ |
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write_unlock(&fs_info->tree_mod_log_lock); |
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return; |
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} |
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min_seq = first->seq; |
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} |
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|
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/* |
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* Anything that's lower than the lowest existing (read: blocked) |
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* sequence number can be removed from the tree. |
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*/ |
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tm_root = &fs_info->tree_mod_log; |
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for (node = rb_first(tm_root); node; node = next) { |
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next = rb_next(node); |
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tm = rb_entry(node, struct tree_mod_elem, node); |
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if (tm->seq >= min_seq) |
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continue; |
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rb_erase(node, tm_root); |
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kfree(tm); |
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} |
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write_unlock(&fs_info->tree_mod_log_lock); |
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} |
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|
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/* |
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* Key order of the log: |
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* node/leaf start address -> sequence |
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* |
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* The 'start address' is the logical address of the *new* root node for root |
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* replace operations, or the logical address of the affected block for all |
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* other operations. |
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*/ |
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static noinline int tree_mod_log_insert(struct btrfs_fs_info *fs_info, |
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struct tree_mod_elem *tm) |
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{ |
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struct rb_root *tm_root; |
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struct rb_node **new; |
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struct rb_node *parent = NULL; |
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struct tree_mod_elem *cur; |
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|
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lockdep_assert_held_write(&fs_info->tree_mod_log_lock); |
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tm->seq = btrfs_inc_tree_mod_seq(fs_info); |
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|
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tm_root = &fs_info->tree_mod_log; |
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new = &tm_root->rb_node; |
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while (*new) { |
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cur = rb_entry(*new, struct tree_mod_elem, node); |
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parent = *new; |
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if (cur->logical < tm->logical) |
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new = &((*new)->rb_left); |
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else if (cur->logical > tm->logical) |
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new = &((*new)->rb_right); |
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else if (cur->seq < tm->seq) |
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new = &((*new)->rb_left); |
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else if (cur->seq > tm->seq) |
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new = &((*new)->rb_right); |
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else |
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return -EEXIST; |
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} |
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|
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rb_link_node(&tm->node, parent, new); |
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rb_insert_color(&tm->node, tm_root); |
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return 0; |
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} |
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|
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/* |
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* Determines if logging can be omitted. Returns true if it can. Otherwise, it |
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* returns false with the tree_mod_log_lock acquired. The caller must hold |
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* this until all tree mod log insertions are recorded in the rb tree and then |
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* write unlock fs_info::tree_mod_log_lock. |
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*/ |
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static inline bool tree_mod_dont_log(struct btrfs_fs_info *fs_info, |
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struct extent_buffer *eb) |
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{ |
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if (!test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags)) |
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return true; |
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if (eb && btrfs_header_level(eb) == 0) |
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return true; |
|
|
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write_lock(&fs_info->tree_mod_log_lock); |
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if (list_empty(&(fs_info)->tree_mod_seq_list)) { |
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write_unlock(&fs_info->tree_mod_log_lock); |
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return true; |
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} |
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|
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return false; |
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} |
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|
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/* Similar to tree_mod_dont_log, but doesn't acquire any locks. */ |
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static inline bool tree_mod_need_log(const struct btrfs_fs_info *fs_info, |
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struct extent_buffer *eb) |
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{ |
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if (!test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags)) |
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return false; |
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if (eb && btrfs_header_level(eb) == 0) |
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return false; |
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|
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return true; |
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} |
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|
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static struct tree_mod_elem *alloc_tree_mod_elem(struct extent_buffer *eb, |
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int slot, |
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enum btrfs_mod_log_op op, |
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gfp_t flags) |
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{ |
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struct tree_mod_elem *tm; |
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|
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tm = kzalloc(sizeof(*tm), flags); |
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if (!tm) |
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return NULL; |
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|
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tm->logical = eb->start; |
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if (op != BTRFS_MOD_LOG_KEY_ADD) { |
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btrfs_node_key(eb, &tm->key, slot); |
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tm->blockptr = btrfs_node_blockptr(eb, slot); |
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} |
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tm->op = op; |
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tm->slot = slot; |
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tm->generation = btrfs_node_ptr_generation(eb, slot); |
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RB_CLEAR_NODE(&tm->node); |
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|
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return tm; |
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} |
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|
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int btrfs_tree_mod_log_insert_key(struct extent_buffer *eb, int slot, |
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enum btrfs_mod_log_op op, gfp_t flags) |
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{ |
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struct tree_mod_elem *tm; |
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int ret; |
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|
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if (!tree_mod_need_log(eb->fs_info, eb)) |
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return 0; |
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|
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tm = alloc_tree_mod_elem(eb, slot, op, flags); |
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if (!tm) |
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return -ENOMEM; |
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|
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if (tree_mod_dont_log(eb->fs_info, eb)) { |
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kfree(tm); |
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return 0; |
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} |
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|
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ret = tree_mod_log_insert(eb->fs_info, tm); |
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write_unlock(&eb->fs_info->tree_mod_log_lock); |
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if (ret) |
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kfree(tm); |
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|
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return ret; |
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} |
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|
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int btrfs_tree_mod_log_insert_move(struct extent_buffer *eb, |
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int dst_slot, int src_slot, |
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int nr_items) |
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{ |
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struct tree_mod_elem *tm = NULL; |
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struct tree_mod_elem **tm_list = NULL; |
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int ret = 0; |
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int i; |
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bool locked = false; |
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if (!tree_mod_need_log(eb->fs_info, eb)) |
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return 0; |
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tm_list = kcalloc(nr_items, sizeof(struct tree_mod_elem *), GFP_NOFS); |
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if (!tm_list) |
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return -ENOMEM; |
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tm = kzalloc(sizeof(*tm), GFP_NOFS); |
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if (!tm) { |
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ret = -ENOMEM; |
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goto free_tms; |
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} |
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tm->logical = eb->start; |
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tm->slot = src_slot; |
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tm->move.dst_slot = dst_slot; |
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tm->move.nr_items = nr_items; |
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tm->op = BTRFS_MOD_LOG_MOVE_KEYS; |
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for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) { |
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tm_list[i] = alloc_tree_mod_elem(eb, i + dst_slot, |
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BTRFS_MOD_LOG_KEY_REMOVE_WHILE_MOVING, GFP_NOFS); |
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if (!tm_list[i]) { |
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ret = -ENOMEM; |
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goto free_tms; |
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} |
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} |
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|
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if (tree_mod_dont_log(eb->fs_info, eb)) |
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goto free_tms; |
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locked = true; |
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|
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/* |
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* When we override something during the move, we log these removals. |
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* This can only happen when we move towards the beginning of the |
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* buffer, i.e. dst_slot < src_slot. |
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*/ |
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for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) { |
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ret = tree_mod_log_insert(eb->fs_info, tm_list[i]); |
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if (ret) |
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goto free_tms; |
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} |
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ret = tree_mod_log_insert(eb->fs_info, tm); |
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if (ret) |
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goto free_tms; |
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write_unlock(&eb->fs_info->tree_mod_log_lock); |
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kfree(tm_list); |
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|
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return 0; |
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|
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free_tms: |
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for (i = 0; i < nr_items; i++) { |
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if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node)) |
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rb_erase(&tm_list[i]->node, &eb->fs_info->tree_mod_log); |
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kfree(tm_list[i]); |
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} |
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if (locked) |
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write_unlock(&eb->fs_info->tree_mod_log_lock); |
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kfree(tm_list); |
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kfree(tm); |
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|
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return ret; |
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} |
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|
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static inline int tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, |
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struct tree_mod_elem **tm_list, |
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int nritems) |
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{ |
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int i, j; |
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int ret; |
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|
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for (i = nritems - 1; i >= 0; i--) { |
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ret = tree_mod_log_insert(fs_info, tm_list[i]); |
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if (ret) { |
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for (j = nritems - 1; j > i; j--) |
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rb_erase(&tm_list[j]->node, |
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&fs_info->tree_mod_log); |
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return ret; |
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} |
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} |
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|
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return 0; |
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} |
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|
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int btrfs_tree_mod_log_insert_root(struct extent_buffer *old_root, |
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struct extent_buffer *new_root, |
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bool log_removal) |
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{ |
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struct btrfs_fs_info *fs_info = old_root->fs_info; |
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struct tree_mod_elem *tm = NULL; |
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struct tree_mod_elem **tm_list = NULL; |
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int nritems = 0; |
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int ret = 0; |
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int i; |
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|
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if (!tree_mod_need_log(fs_info, NULL)) |
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return 0; |
|
|
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if (log_removal && btrfs_header_level(old_root) > 0) { |
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nritems = btrfs_header_nritems(old_root); |
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tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *), |
|
GFP_NOFS); |
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if (!tm_list) { |
|
ret = -ENOMEM; |
|
goto free_tms; |
|
} |
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for (i = 0; i < nritems; i++) { |
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tm_list[i] = alloc_tree_mod_elem(old_root, i, |
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BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING, GFP_NOFS); |
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if (!tm_list[i]) { |
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ret = -ENOMEM; |
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goto free_tms; |
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} |
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} |
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} |
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|
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tm = kzalloc(sizeof(*tm), GFP_NOFS); |
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if (!tm) { |
|
ret = -ENOMEM; |
|
goto free_tms; |
|
} |
|
|
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tm->logical = new_root->start; |
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tm->old_root.logical = old_root->start; |
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tm->old_root.level = btrfs_header_level(old_root); |
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tm->generation = btrfs_header_generation(old_root); |
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tm->op = BTRFS_MOD_LOG_ROOT_REPLACE; |
|
|
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if (tree_mod_dont_log(fs_info, NULL)) |
|
goto free_tms; |
|
|
|
if (tm_list) |
|
ret = tree_mod_log_free_eb(fs_info, tm_list, nritems); |
|
if (!ret) |
|
ret = tree_mod_log_insert(fs_info, tm); |
|
|
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write_unlock(&fs_info->tree_mod_log_lock); |
|
if (ret) |
|
goto free_tms; |
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kfree(tm_list); |
|
|
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return ret; |
|
|
|
free_tms: |
|
if (tm_list) { |
|
for (i = 0; i < nritems; i++) |
|
kfree(tm_list[i]); |
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kfree(tm_list); |
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} |
|
kfree(tm); |
|
|
|
return ret; |
|
} |
|
|
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static struct tree_mod_elem *__tree_mod_log_search(struct btrfs_fs_info *fs_info, |
|
u64 start, u64 min_seq, |
|
bool smallest) |
|
{ |
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struct rb_root *tm_root; |
|
struct rb_node *node; |
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struct tree_mod_elem *cur = NULL; |
|
struct tree_mod_elem *found = NULL; |
|
|
|
read_lock(&fs_info->tree_mod_log_lock); |
|
tm_root = &fs_info->tree_mod_log; |
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node = tm_root->rb_node; |
|
while (node) { |
|
cur = rb_entry(node, struct tree_mod_elem, node); |
|
if (cur->logical < start) { |
|
node = node->rb_left; |
|
} else if (cur->logical > start) { |
|
node = node->rb_right; |
|
} else if (cur->seq < min_seq) { |
|
node = node->rb_left; |
|
} else if (!smallest) { |
|
/* We want the node with the highest seq */ |
|
if (found) |
|
BUG_ON(found->seq > cur->seq); |
|
found = cur; |
|
node = node->rb_left; |
|
} else if (cur->seq > min_seq) { |
|
/* We want the node with the smallest seq */ |
|
if (found) |
|
BUG_ON(found->seq < cur->seq); |
|
found = cur; |
|
node = node->rb_right; |
|
} else { |
|
found = cur; |
|
break; |
|
} |
|
} |
|
read_unlock(&fs_info->tree_mod_log_lock); |
|
|
|
return found; |
|
} |
|
|
|
/* |
|
* This returns the element from the log with the smallest time sequence |
|
* value that's in the log (the oldest log item). Any element with a time |
|
* sequence lower than min_seq will be ignored. |
|
*/ |
|
static struct tree_mod_elem *tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, |
|
u64 start, u64 min_seq) |
|
{ |
|
return __tree_mod_log_search(fs_info, start, min_seq, true); |
|
} |
|
|
|
/* |
|
* This returns the element from the log with the largest time sequence |
|
* value that's in the log (the most recent log item). Any element with |
|
* a time sequence lower than min_seq will be ignored. |
|
*/ |
|
static struct tree_mod_elem *tree_mod_log_search(struct btrfs_fs_info *fs_info, |
|
u64 start, u64 min_seq) |
|
{ |
|
return __tree_mod_log_search(fs_info, start, min_seq, false); |
|
} |
|
|
|
int btrfs_tree_mod_log_eb_copy(struct extent_buffer *dst, |
|
struct extent_buffer *src, |
|
unsigned long dst_offset, |
|
unsigned long src_offset, |
|
int nr_items) |
|
{ |
|
struct btrfs_fs_info *fs_info = dst->fs_info; |
|
int ret = 0; |
|
struct tree_mod_elem **tm_list = NULL; |
|
struct tree_mod_elem **tm_list_add, **tm_list_rem; |
|
int i; |
|
bool locked = false; |
|
|
|
if (!tree_mod_need_log(fs_info, NULL)) |
|
return 0; |
|
|
|
if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0) |
|
return 0; |
|
|
|
tm_list = kcalloc(nr_items * 2, sizeof(struct tree_mod_elem *), |
|
GFP_NOFS); |
|
if (!tm_list) |
|
return -ENOMEM; |
|
|
|
tm_list_add = tm_list; |
|
tm_list_rem = tm_list + nr_items; |
|
for (i = 0; i < nr_items; i++) { |
|
tm_list_rem[i] = alloc_tree_mod_elem(src, i + src_offset, |
|
BTRFS_MOD_LOG_KEY_REMOVE, GFP_NOFS); |
|
if (!tm_list_rem[i]) { |
|
ret = -ENOMEM; |
|
goto free_tms; |
|
} |
|
|
|
tm_list_add[i] = alloc_tree_mod_elem(dst, i + dst_offset, |
|
BTRFS_MOD_LOG_KEY_ADD, GFP_NOFS); |
|
if (!tm_list_add[i]) { |
|
ret = -ENOMEM; |
|
goto free_tms; |
|
} |
|
} |
|
|
|
if (tree_mod_dont_log(fs_info, NULL)) |
|
goto free_tms; |
|
locked = true; |
|
|
|
for (i = 0; i < nr_items; i++) { |
|
ret = tree_mod_log_insert(fs_info, tm_list_rem[i]); |
|
if (ret) |
|
goto free_tms; |
|
ret = tree_mod_log_insert(fs_info, tm_list_add[i]); |
|
if (ret) |
|
goto free_tms; |
|
} |
|
|
|
write_unlock(&fs_info->tree_mod_log_lock); |
|
kfree(tm_list); |
|
|
|
return 0; |
|
|
|
free_tms: |
|
for (i = 0; i < nr_items * 2; i++) { |
|
if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node)) |
|
rb_erase(&tm_list[i]->node, &fs_info->tree_mod_log); |
|
kfree(tm_list[i]); |
|
} |
|
if (locked) |
|
write_unlock(&fs_info->tree_mod_log_lock); |
|
kfree(tm_list); |
|
|
|
return ret; |
|
} |
|
|
|
int btrfs_tree_mod_log_free_eb(struct extent_buffer *eb) |
|
{ |
|
struct tree_mod_elem **tm_list = NULL; |
|
int nritems = 0; |
|
int i; |
|
int ret = 0; |
|
|
|
if (!tree_mod_need_log(eb->fs_info, eb)) |
|
return 0; |
|
|
|
nritems = btrfs_header_nritems(eb); |
|
tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *), GFP_NOFS); |
|
if (!tm_list) |
|
return -ENOMEM; |
|
|
|
for (i = 0; i < nritems; i++) { |
|
tm_list[i] = alloc_tree_mod_elem(eb, i, |
|
BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING, GFP_NOFS); |
|
if (!tm_list[i]) { |
|
ret = -ENOMEM; |
|
goto free_tms; |
|
} |
|
} |
|
|
|
if (tree_mod_dont_log(eb->fs_info, eb)) |
|
goto free_tms; |
|
|
|
ret = tree_mod_log_free_eb(eb->fs_info, tm_list, nritems); |
|
write_unlock(&eb->fs_info->tree_mod_log_lock); |
|
if (ret) |
|
goto free_tms; |
|
kfree(tm_list); |
|
|
|
return 0; |
|
|
|
free_tms: |
|
for (i = 0; i < nritems; i++) |
|
kfree(tm_list[i]); |
|
kfree(tm_list); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* Returns the logical address of the oldest predecessor of the given root. |
|
* Entries older than time_seq are ignored. |
|
*/ |
|
static struct tree_mod_elem *tree_mod_log_oldest_root(struct extent_buffer *eb_root, |
|
u64 time_seq) |
|
{ |
|
struct tree_mod_elem *tm; |
|
struct tree_mod_elem *found = NULL; |
|
u64 root_logical = eb_root->start; |
|
bool looped = false; |
|
|
|
if (!time_seq) |
|
return NULL; |
|
|
|
/* |
|
* The very last operation that's logged for a root is the replacement |
|
* operation (if it is replaced at all). This has the logical address |
|
* of the *new* root, making it the very first operation that's logged |
|
* for this root. |
|
*/ |
|
while (1) { |
|
tm = tree_mod_log_search_oldest(eb_root->fs_info, root_logical, |
|
time_seq); |
|
if (!looped && !tm) |
|
return NULL; |
|
/* |
|
* If there are no tree operation for the oldest root, we simply |
|
* return it. This should only happen if that (old) root is at |
|
* level 0. |
|
*/ |
|
if (!tm) |
|
break; |
|
|
|
/* |
|
* If there's an operation that's not a root replacement, we |
|
* found the oldest version of our root. Normally, we'll find a |
|
* BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here. |
|
*/ |
|
if (tm->op != BTRFS_MOD_LOG_ROOT_REPLACE) |
|
break; |
|
|
|
found = tm; |
|
root_logical = tm->old_root.logical; |
|
looped = true; |
|
} |
|
|
|
/* If there's no old root to return, return what we found instead */ |
|
if (!found) |
|
found = tm; |
|
|
|
return found; |
|
} |
|
|
|
|
|
/* |
|
* tm is a pointer to the first operation to rewind within eb. Then, all |
|
* previous operations will be rewound (until we reach something older than |
|
* time_seq). |
|
*/ |
|
static void tree_mod_log_rewind(struct btrfs_fs_info *fs_info, |
|
struct extent_buffer *eb, |
|
u64 time_seq, |
|
struct tree_mod_elem *first_tm) |
|
{ |
|
u32 n; |
|
struct rb_node *next; |
|
struct tree_mod_elem *tm = first_tm; |
|
unsigned long o_dst; |
|
unsigned long o_src; |
|
unsigned long p_size = sizeof(struct btrfs_key_ptr); |
|
|
|
n = btrfs_header_nritems(eb); |
|
read_lock(&fs_info->tree_mod_log_lock); |
|
while (tm && tm->seq >= time_seq) { |
|
/* |
|
* All the operations are recorded with the operator used for |
|
* the modification. As we're going backwards, we do the |
|
* opposite of each operation here. |
|
*/ |
|
switch (tm->op) { |
|
case BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING: |
|
BUG_ON(tm->slot < n); |
|
fallthrough; |
|
case BTRFS_MOD_LOG_KEY_REMOVE_WHILE_MOVING: |
|
case BTRFS_MOD_LOG_KEY_REMOVE: |
|
btrfs_set_node_key(eb, &tm->key, tm->slot); |
|
btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr); |
|
btrfs_set_node_ptr_generation(eb, tm->slot, |
|
tm->generation); |
|
n++; |
|
break; |
|
case BTRFS_MOD_LOG_KEY_REPLACE: |
|
BUG_ON(tm->slot >= n); |
|
btrfs_set_node_key(eb, &tm->key, tm->slot); |
|
btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr); |
|
btrfs_set_node_ptr_generation(eb, tm->slot, |
|
tm->generation); |
|
break; |
|
case BTRFS_MOD_LOG_KEY_ADD: |
|
/* if a move operation is needed it's in the log */ |
|
n--; |
|
break; |
|
case BTRFS_MOD_LOG_MOVE_KEYS: |
|
o_dst = btrfs_node_key_ptr_offset(tm->slot); |
|
o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot); |
|
memmove_extent_buffer(eb, o_dst, o_src, |
|
tm->move.nr_items * p_size); |
|
break; |
|
case BTRFS_MOD_LOG_ROOT_REPLACE: |
|
/* |
|
* This operation is special. For roots, this must be |
|
* handled explicitly before rewinding. |
|
* For non-roots, this operation may exist if the node |
|
* was a root: root A -> child B; then A gets empty and |
|
* B is promoted to the new root. In the mod log, we'll |
|
* have a root-replace operation for B, a tree block |
|
* that is no root. We simply ignore that operation. |
|
*/ |
|
break; |
|
} |
|
next = rb_next(&tm->node); |
|
if (!next) |
|
break; |
|
tm = rb_entry(next, struct tree_mod_elem, node); |
|
if (tm->logical != first_tm->logical) |
|
break; |
|
} |
|
read_unlock(&fs_info->tree_mod_log_lock); |
|
btrfs_set_header_nritems(eb, n); |
|
} |
|
|
|
/* |
|
* Called with eb read locked. If the buffer cannot be rewound, the same buffer |
|
* is returned. If rewind operations happen, a fresh buffer is returned. The |
|
* returned buffer is always read-locked. If the returned buffer is not the |
|
* input buffer, the lock on the input buffer is released and the input buffer |
|
* is freed (its refcount is decremented). |
|
*/ |
|
struct extent_buffer *btrfs_tree_mod_log_rewind(struct btrfs_fs_info *fs_info, |
|
struct btrfs_path *path, |
|
struct extent_buffer *eb, |
|
u64 time_seq) |
|
{ |
|
struct extent_buffer *eb_rewin; |
|
struct tree_mod_elem *tm; |
|
|
|
if (!time_seq) |
|
return eb; |
|
|
|
if (btrfs_header_level(eb) == 0) |
|
return eb; |
|
|
|
tm = tree_mod_log_search(fs_info, eb->start, time_seq); |
|
if (!tm) |
|
return eb; |
|
|
|
if (tm->op == BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING) { |
|
BUG_ON(tm->slot != 0); |
|
eb_rewin = alloc_dummy_extent_buffer(fs_info, eb->start); |
|
if (!eb_rewin) { |
|
btrfs_tree_read_unlock(eb); |
|
free_extent_buffer(eb); |
|
return NULL; |
|
} |
|
btrfs_set_header_bytenr(eb_rewin, eb->start); |
|
btrfs_set_header_backref_rev(eb_rewin, |
|
btrfs_header_backref_rev(eb)); |
|
btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb)); |
|
btrfs_set_header_level(eb_rewin, btrfs_header_level(eb)); |
|
} else { |
|
eb_rewin = btrfs_clone_extent_buffer(eb); |
|
if (!eb_rewin) { |
|
btrfs_tree_read_unlock(eb); |
|
free_extent_buffer(eb); |
|
return NULL; |
|
} |
|
} |
|
|
|
btrfs_tree_read_unlock(eb); |
|
free_extent_buffer(eb); |
|
|
|
btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb_rewin), |
|
eb_rewin, btrfs_header_level(eb_rewin)); |
|
btrfs_tree_read_lock(eb_rewin); |
|
tree_mod_log_rewind(fs_info, eb_rewin, time_seq, tm); |
|
WARN_ON(btrfs_header_nritems(eb_rewin) > |
|
BTRFS_NODEPTRS_PER_BLOCK(fs_info)); |
|
|
|
return eb_rewin; |
|
} |
|
|
|
/* |
|
* Rewind the state of @root's root node to the given @time_seq value. |
|
* If there are no changes, the current root->root_node is returned. If anything |
|
* changed in between, there's a fresh buffer allocated on which the rewind |
|
* operations are done. In any case, the returned buffer is read locked. |
|
* Returns NULL on error (with no locks held). |
|
*/ |
|
struct extent_buffer *btrfs_get_old_root(struct btrfs_root *root, u64 time_seq) |
|
{ |
|
struct btrfs_fs_info *fs_info = root->fs_info; |
|
struct tree_mod_elem *tm; |
|
struct extent_buffer *eb = NULL; |
|
struct extent_buffer *eb_root; |
|
u64 eb_root_owner = 0; |
|
struct extent_buffer *old; |
|
struct tree_mod_root *old_root = NULL; |
|
u64 old_generation = 0; |
|
u64 logical; |
|
int level; |
|
|
|
eb_root = btrfs_read_lock_root_node(root); |
|
tm = tree_mod_log_oldest_root(eb_root, time_seq); |
|
if (!tm) |
|
return eb_root; |
|
|
|
if (tm->op == BTRFS_MOD_LOG_ROOT_REPLACE) { |
|
old_root = &tm->old_root; |
|
old_generation = tm->generation; |
|
logical = old_root->logical; |
|
level = old_root->level; |
|
} else { |
|
logical = eb_root->start; |
|
level = btrfs_header_level(eb_root); |
|
} |
|
|
|
tm = tree_mod_log_search(fs_info, logical, time_seq); |
|
if (old_root && tm && tm->op != BTRFS_MOD_LOG_KEY_REMOVE_WHILE_FREEING) { |
|
btrfs_tree_read_unlock(eb_root); |
|
free_extent_buffer(eb_root); |
|
old = read_tree_block(fs_info, logical, root->root_key.objectid, |
|
0, level, NULL); |
|
if (WARN_ON(IS_ERR(old) || !extent_buffer_uptodate(old))) { |
|
if (!IS_ERR(old)) |
|
free_extent_buffer(old); |
|
btrfs_warn(fs_info, |
|
"failed to read tree block %llu from get_old_root", |
|
logical); |
|
} else { |
|
struct tree_mod_elem *tm2; |
|
|
|
btrfs_tree_read_lock(old); |
|
eb = btrfs_clone_extent_buffer(old); |
|
/* |
|
* After the lookup for the most recent tree mod operation |
|
* above and before we locked and cloned the extent buffer |
|
* 'old', a new tree mod log operation may have been added. |
|
* So lookup for a more recent one to make sure the number |
|
* of mod log operations we replay is consistent with the |
|
* number of items we have in the cloned extent buffer, |
|
* otherwise we can hit a BUG_ON when rewinding the extent |
|
* buffer. |
|
*/ |
|
tm2 = tree_mod_log_search(fs_info, logical, time_seq); |
|
btrfs_tree_read_unlock(old); |
|
free_extent_buffer(old); |
|
ASSERT(tm2); |
|
ASSERT(tm2 == tm || tm2->seq > tm->seq); |
|
if (!tm2 || tm2->seq < tm->seq) { |
|
free_extent_buffer(eb); |
|
return NULL; |
|
} |
|
tm = tm2; |
|
} |
|
} else if (old_root) { |
|
eb_root_owner = btrfs_header_owner(eb_root); |
|
btrfs_tree_read_unlock(eb_root); |
|
free_extent_buffer(eb_root); |
|
eb = alloc_dummy_extent_buffer(fs_info, logical); |
|
} else { |
|
eb = btrfs_clone_extent_buffer(eb_root); |
|
btrfs_tree_read_unlock(eb_root); |
|
free_extent_buffer(eb_root); |
|
} |
|
|
|
if (!eb) |
|
return NULL; |
|
if (old_root) { |
|
btrfs_set_header_bytenr(eb, eb->start); |
|
btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV); |
|
btrfs_set_header_owner(eb, eb_root_owner); |
|
btrfs_set_header_level(eb, old_root->level); |
|
btrfs_set_header_generation(eb, old_generation); |
|
} |
|
btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb), eb, |
|
btrfs_header_level(eb)); |
|
btrfs_tree_read_lock(eb); |
|
if (tm) |
|
tree_mod_log_rewind(fs_info, eb, time_seq, tm); |
|
else |
|
WARN_ON(btrfs_header_level(eb) != 0); |
|
WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(fs_info)); |
|
|
|
return eb; |
|
} |
|
|
|
int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq) |
|
{ |
|
struct tree_mod_elem *tm; |
|
int level; |
|
struct extent_buffer *eb_root = btrfs_root_node(root); |
|
|
|
tm = tree_mod_log_oldest_root(eb_root, time_seq); |
|
if (tm && tm->op == BTRFS_MOD_LOG_ROOT_REPLACE) |
|
level = tm->old_root.level; |
|
else |
|
level = btrfs_header_level(eb_root); |
|
|
|
free_extent_buffer(eb_root); |
|
|
|
return level; |
|
} |
|
|
|
/* |
|
* Return the lowest sequence number in the tree modification log. |
|
* |
|
* Return the sequence number of the oldest tree modification log user, which |
|
* corresponds to the lowest sequence number of all existing users. If there are |
|
* no users it returns 0. |
|
*/ |
|
u64 btrfs_tree_mod_log_lowest_seq(struct btrfs_fs_info *fs_info) |
|
{ |
|
u64 ret = 0; |
|
|
|
read_lock(&fs_info->tree_mod_log_lock); |
|
if (!list_empty(&fs_info->tree_mod_seq_list)) { |
|
struct btrfs_seq_list *elem; |
|
|
|
elem = list_first_entry(&fs_info->tree_mod_seq_list, |
|
struct btrfs_seq_list, list); |
|
ret = elem->seq; |
|
} |
|
read_unlock(&fs_info->tree_mod_log_lock); |
|
|
|
return ret; |
|
}
|
|
|