[PATCH] xfs: check return codes when flushing block devices

["Darrick J. Wong" <djwong@kernel.org>]

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

If a block device cache flush fails, fsync needs to report that to upper
levels.  If the log can't flush the data device, we should shut it down
immediately because we've just violated an invariant.  Hence, check the
return value of blkdev_issue_flush.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/xfs_file.c |   15 ++++++++++-----
 fs/xfs/xfs_log.c  |    7 +++++--
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 5a171c0b244b..88450c33ab01 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -163,9 +163,11 @@ xfs_file_fsync(
 	 * inode size in case of an extending write.
 	 */
 	if (XFS_IS_REALTIME_INODE(ip))
-		blkdev_issue_flush(mp->m_rtdev_targp->bt_bdev);
+		error = blkdev_issue_flush(mp->m_rtdev_targp->bt_bdev);
 	else if (mp->m_logdev_targp != mp->m_ddev_targp)
-		blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
+		error = blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
+	if (error)
+		return error;
 
 	/*
 	 * Any inode that has dirty modifications in the log is pinned.  The
@@ -173,8 +175,11 @@ xfs_file_fsync(
 	 * that happen concurrently to the fsync call, but fsync semantics
 	 * only require to sync previously completed I/O.
 	 */
-	if (xfs_ipincount(ip))
+	if (xfs_ipincount(ip)) {
 		error = xfs_fsync_flush_log(ip, datasync, &log_flushed);
+		if (error)
+			return error;
+	}
 
 	/*
 	 * If we only have a single device, and the log force about was
@@ -185,9 +190,9 @@ xfs_file_fsync(
 	 */
 	if (!log_flushed && !XFS_IS_REALTIME_INODE(ip) &&
 	    mp->m_logdev_targp == mp->m_ddev_targp)
-		blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
+		return blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
 
-	return error;
+	return 0;
 }
 
 static int
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 4b1c0a9c6368..8a767f4145f0 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1926,8 +1926,11 @@ xlog_write_iclog(
 		 * by the LSN in this iclog is on stable storage. This is slow,
 		 * but it *must* complete before we issue the external log IO.
 		 */
-		if (log->l_targ != log->l_mp->m_ddev_targp)
-			blkdev_issue_flush(log->l_mp->m_ddev_targp->bt_bdev);
+		if (log->l_targ != log->l_mp->m_ddev_targp &&
+		    blkdev_issue_flush(log->l_mp->m_ddev_targp->bt_bdev)) {
+			xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
+			return;
+		}
 	}
 	if (iclog->ic_flags & XLOG_ICL_NEED_FUA)
 		iclog->ic_bio.bi_opf |= REQ_FUA;