[PATCH 5.10 CANDIDATE 4/6] vfs: make sync_filesystem return errors from ->sync_fs

[Amir Goldstein <amir73il@gmail.com>]

From: "Darrick J. Wong" <djwong@kernel.org>

commit 5679897eb104cec9e99609c3f045a0c20603da4c upstream.

[backport to 5.10 only differs in __sync_blockdev helper]

Strangely, sync_filesystem ignores the return code from the ->sync_fs
call, which means that syscalls like syncfs(2) never see the error.
This doesn't seem right, so fix that.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/sync.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/fs/sync.c b/fs/sync.c
index 0d6cdc507cb9..79180e58d862 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -28,7 +28,7 @@
  */
 int sync_filesystem(struct super_block *sb)
 {
-	int ret;
+	int ret = 0;
 
 	/*
 	 * We need to be protected against the filesystem going from
@@ -51,15 +51,21 @@ int sync_filesystem(struct super_block *sb)
 	 * at a time.
 	 */
 	writeback_inodes_sb(sb, WB_REASON_SYNC);
-	if (sb->s_op->sync_fs)
-		sb->s_op->sync_fs(sb, 0);
+	if (sb->s_op->sync_fs) {
+		ret = sb->s_op->sync_fs(sb, 0);
+		if (ret)
+			return ret;
+	}
 	ret = __sync_blockdev(sb->s_bdev, 0);
-	if (ret < 0)
+	if (ret)
 		return ret;
 
 	sync_inodes_sb(sb);
-	if (sb->s_op->sync_fs)
-		sb->s_op->sync_fs(sb, 1);
+	if (sb->s_op->sync_fs) {
+		ret = sb->s_op->sync_fs(sb, 1);
+		if (ret)
+			return ret;
+	}
 	return __sync_blockdev(sb->s_bdev, 1);
 }
 EXPORT_SYMBOL(sync_filesystem);
-- 
2.25.1