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Btrfs: tree mod log's old roots could still be part of the tree

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Tree mod log treated old root buffers as always empty buffers when starting
the rewind operations. However, the old root may still be part of the
current tree at a lower level, with still some valid entries.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
This commit is contained in:
Jan Schmidt 2012-10-23 11:27:33 +02:00
parent ba1bfbd592
commit 834328a849
1 changed files with 21 additions and 4 deletions
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25
fs/btrfs/ctree.c
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@ -1239,6 +1239,7 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
struct tree_mod_root *old_root = NULL;
u64 old_generation = 0;
u64 logical;
u32 blocksize;
eb = btrfs_read_lock_root_node(root);
tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq);
@ -1254,12 +1255,28 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
}
tm = tree_mod_log_search(root->fs_info, logical, time_seq);
if (old_root)
if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
btrfs_tree_read_unlock(root->node);
free_extent_buffer(root->node);
blocksize = btrfs_level_size(root, old_root->level);
eb = read_tree_block(root, logical, blocksize, 0);
if (!eb) {
pr_warn("btrfs: failed to read tree block %llu from get_old_root\n",
logical);
WARN_ON(1);
} else {
eb = btrfs_clone_extent_buffer(eb);
}
} else if (old_root) {
btrfs_tree_read_unlock(root->node);
free_extent_buffer(root->node);
eb = alloc_dummy_extent_buffer(logical, root->nodesize);
else
} else {
eb = btrfs_clone_extent_buffer(root->node);
btrfs_tree_read_unlock(root->node);
free_extent_buffer(root->node);
btrfs_tree_read_unlock(root->node);
free_extent_buffer(root->node);
}
if (!eb)
return NULL;
btrfs_tree_read_lock(eb);