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@xxxxxxxxxxxxx>
---
fs/btrfs/ctree.c | 16 ++++++++++++++--
1 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index e6b75cc..1b60c56 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -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);
@@ -1254,10 +1255,21 @@ 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) {
+ 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) {
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);
if (!eb)
--
1.7.1
--
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