[PATCH] ext4: fix blkdev_issue_flush() failure handling

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

blkdev_issue_flush() may fail (i.e. due to media error on FLUSH CACHE
command execution) so its users should check for the return value.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
 fs/ext4/fsync.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Index: b/fs/ext4/fsync.c
===================================================================
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -48,7 +48,7 @@ int ext4_sync_file(struct file *file, st
 {
 	struct inode *inode = dentry->d_inode;
 	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
-	int ret = 0;
+	int ret = 0, tmp_ret;
 
 	J_ASSERT(ext4_journal_current_handle() == NULL);
 
@@ -92,8 +92,11 @@ int ext4_sync_file(struct file *file, st
 			.nr_to_write = 0, /* sys_fsync did this */
 		};
 		ret = sync_inode(inode, &wbc);
-		if (journal && (journal->j_flags & JBD2_BARRIER))
-			blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
+		if (journal && (journal->j_flags & JBD2_BARRIER)) {
+			tmp_ret = blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
+			if (ret == 0 && tmp_ret < 0 && tmp_ret != -EOPNOTSUPP)
+				ret = tmp_ret;
+		}
 	}
 out:
 	return ret;