btrfs_relocate_chunk() initiates new ordered extents. They can cause a
hang when a process is trying to thaw the filesystem.
We should have called sb_start_write(), so the filesystem is not being
frozen. Add an ASSERT to check it is protected.
Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
---
fs/btrfs/volumes.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 3471698fd831..393fc7db99d3 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3230,6 +3230,9 @@ int btrfs_relocate_chunk(struct btrfs_fs_info *fs_info, u64 chunk_offset)
u64 length;
int ret;
+ /* Assert we called sb_start_write(), not to race with FS freezing */
+ ASSERT(sb_write_started(fs_info->sb));
+
if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
btrfs_err(fs_info,
"relocate: not supported on extent tree v2 yet");
--
2.35.1
