Btrfs: fix copy_items() return value when logging an inode

fdmanana · kdave · commit 8434ec46c6e3 · 2018-03-31T02:01:05.000+02:00
When logging an inode, at tree-log.c:copy_items(), if we call btrfs_next_leaf() at the loop which checks for the need to log holes, we need to make sure copy_items() returns the value 1 to its caller and not 0 (on success). This is because the path the caller passed was released and is now different from what is was before, and the caller expects a return value of 0 to mean both success and that the path has not changed, while a return value of 1 means both success and signals the caller that it can not reuse the path, it has to perform another tree search. Even though this is a case that should not be triggered on normal circumstances or very rare at least, its consequences can be very unpredictable (especially when replaying a log tree). Fixes: 16e7549 ("Btrfs: incompatible format change to remove hole extents") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
@@ -3968,6 +3968,7 @@ static noinline int copy_items(struct btrfs_trans_handle *trans,
 			ASSERT(ret == 0);
 			src = src_path->nodes[0];
 			i = 0;
+			need_find_last_extent = true;
 		}
 
 		btrfs_item_key_to_cpu(src, &key, i);

Original file line number	Diff line number	Diff line change
`@@ -3968,6 +3968,7 @@ static noinline int copy_items(struct btrfs_trans_handle *trans,`
`3968`	`3968`	`ASSERT(ret == 0);`
`3969`	`3969`	`src = src_path->nodes[0];`
`3970`	`3970`	`i = 0;`
	`3971`	`+ need_find_last_extent = true;`
`3971`	`3972`	`}`
`3972`	`3973`
`3973`	`3974`	`btrfs_item_key_to_cpu(src, &key, i);`