[PATCH] btrfs: fix silent IO error loss in encoded writes and zoned split

[Michal Grzedzicki]

can_finish_ordered_extent() and btrfs_finish_ordered_zoned() set
BTRFS_ORDERED_IOERR via bare set_bit(). Later,
btrfs_mark_ordered_extent_error() in btrfs_finish_one_ordered() uses
test_and_set_bit(), finds it already set, and skips
mapping_set_error(). The error is never recorded on the inode's
address_space, making it invisible to fsync. For encoded writes this
causes btrfs receive to silently produce files with zero-filled holes.

Fix: replace bare set_bit(BTRFS_ORDERED_IOERR) with
btrfs_mark_ordered_extent_error() which pairs test_and_set_bit() with
mapping_set_error(), guaranteeing the error is recorded exactly once.

Signed-off-by: Michal Grzedzicki <mge@xxxxxxxx>
---
 fs/btrfs/ordered-data.c | 2 +-
 fs/btrfs/zoned.c        | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 5df02c707aee..b65c1f1e2956 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -385,7 +385,7 @@ static bool can_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
 	}
 
 	if (!uptodate)
-		set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
+		btrfs_mark_ordered_extent_error(ordered);
 
 	if (ordered->bytes_left)
 		return false;
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 0cd7fd3fcfa3..d728c3bafc09 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -2136,7 +2136,7 @@ void btrfs_finish_ordered_zoned(struct btrfs_ordered_extent *ordered)
 			continue;
 		}
 		if (!btrfs_zoned_split_ordered(ordered, logical, len)) {
-			set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
+			btrfs_mark_ordered_extent_error(ordered);
 			btrfs_err(fs_info, "failed to split ordered extent");
 			goto out;
 		}
-- 
2.52.0