[PATCH 01/10] libext2fs: always fsync the device when flushing the cache

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

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

When we're flushing the unix IO manager's buffer cache, we should always
fsync the block device, because something could have written to the
block device -- either the buffer cache itself, or a direct write.
Regardless, the callers all want all dirtied regions to be persisted to
stable media.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
 lib/ext2fs/unix_io.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)


diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c
index ede75cf8ee3681..40fd9cc1427c31 100644
--- a/lib/ext2fs/unix_io.c
+++ b/lib/ext2fs/unix_io.c
@@ -1452,7 +1452,8 @@ static errcode_t unix_flush(io_channel channel)
 	retval = flush_cached_blocks(channel, data, 0);
 #endif
 #ifdef HAVE_FSYNC
-	if (!retval && fsync(data->dev) != 0)
+	/* always fsync the device, even if flushing our own cache failed */
+	if (fsync(data->dev) != 0 && !retval)
 		return errno;
 #endif
 	return retval;