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-rw-r--r--fs/btrfs/ctree.c28
1 files changed, 15 insertions, 13 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 15cbc2bf4ff0..7d1e4fc5fb6a 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1024,11 +1024,18 @@ __tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info,
if (!looped && !tm)
return 0;
/*
- * we must have key remove operations in the log before the
- * replace operation.
+ * 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.
*/
- BUG_ON(!tm);
+ 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
+ * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
+ */
if (tm->op != MOD_LOG_ROOT_REPLACE)
break;
@@ -1192,16 +1199,8 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
}
tm = tree_mod_log_search(root->fs_info, logical, time_seq);
- /*
- * there was an item in the log when __tree_mod_log_oldest_root
- * returned. this one must not go away, because the time_seq passed to
- * us must be blocking its removal.
- */
- BUG_ON(!tm);
-
if (old_root)
- eb = alloc_dummy_extent_buffer(tm->index << PAGE_CACHE_SHIFT,
- root->nodesize);
+ eb = alloc_dummy_extent_buffer(logical, root->nodesize);
else
eb = btrfs_clone_extent_buffer(root->node);
btrfs_tree_read_unlock(root->node);
@@ -1216,7 +1215,10 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
btrfs_set_header_level(eb, old_root->level);
btrfs_set_header_generation(eb, old_generation);
}
- __tree_mod_log_rewind(eb, time_seq, tm);
+ if (tm)
+ __tree_mod_log_rewind(eb, time_seq, tm);
+ else
+ WARN_ON(btrfs_header_level(eb) != 0);
extent_buffer_get(eb);
return eb;