[XFS] write barrier support Issue all log sync operations as ordered

writes.  In addition flush the disk cache on fsync if the sync cached
operation didn't sync the log to disk (this requires some additional
bookeping in the transaction and log code). If the device doesn't claim to
support barriers, the filesystem has an extern log volume or the trial
superblock write with barriers enabled failed we disable barriers and
print a warning.  We should probably fail the mount completely, but that
could lead to nasty boot failures for the root filesystem.  Not enabled by
default yet, needs more destructive testing first.

SGI-PV: 912426
SGI-Modid: xfs-linux:xfs-kern:198723a

Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
index 18961119fc65..dc920f83412d 100644
--- a/fs/xfs/xfs_log.h
+++ b/fs/xfs/xfs_log.h
@@ -174,9 +174,12 @@ xfs_lsn_t xfs_log_done(struct xfs_mount *mp,
                        xfs_log_ticket_t ticket,
                        void             **iclog,
                        uint             flags);
-int       xfs_log_force(struct xfs_mount *mp,
-                        xfs_lsn_t        lsn,
-                        uint             flags);
+int       _xfs_log_force(struct xfs_mount *mp,
+                         xfs_lsn_t      lsn,
+                         uint           flags,
+                         int            *log_forced);
+#define xfs_log_force(mp, lsn, flags) \
+        _xfs_log_force(mp, lsn, flags, NULL);
 int       xfs_log_mount(struct xfs_mount        *mp,
                         struct xfs_buftarg      *log_target,
                         xfs_daddr_t             start_block,