xfs: only issues a cache flush on unmount if barriers are enabled

Currently we unconditionally issue a flush from xfs_free_buftarg, but
since 2.6.29-rc1 this gives a warning in the style of

	end_request: I/O error, dev vdb, sector 0

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Felix Blyakher <felixb@sgi.com>

3 files changed, 16 insertions, 8 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index cb329edc925b..aa1016bb9134 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -34,6 +34,12 @@
 #include <linux/backing-dev.h>
 #include <linux/freezer.h>
 
+#include "xfs_sb.h"
+#include "xfs_inum.h"
+#include "xfs_ag.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+
 static kmem_zone_t *xfs_buf_zone;
 STATIC int xfsbufd(void *);
 STATIC int xfsbufd_wakeup(int, gfp_t);
@@ -1435,10 +1441,12 @@ xfs_unregister_buftarg(
 
 void
 xfs_free_buftarg(
-        xfs_buftarg_t           *btp)
+        struct xfs_mount        *mp,
+        struct xfs_buftarg      *btp)
 {
         xfs_flush_buftarg(btp, 1);
-        xfs_blkdev_issue_flush(btp);
+        if (mp->m_flags & XFS_MOUNT_BARRIER)
+                xfs_blkdev_issue_flush(btp);
         xfs_free_bufhash(btp);
         iput(btp->bt_mapping->host);
 
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index 288ae7c4c800..9b4d666ad31f 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -413,7 +413,7 @@ static inline int XFS_bwrite(xfs_buf_t *bp)
  *      Handling of buftargs.
  */
 extern xfs_buftarg_t *xfs_alloc_buftarg(struct block_device *, int);
-extern void xfs_free_buftarg(xfs_buftarg_t *);
+extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
 extern void xfs_wait_buftarg(xfs_buftarg_t *);
 extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
 extern int xfs_flush_buftarg(xfs_buftarg_t *, int);
diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index bc1e64708e2b..8483b35821e0 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -733,15 +733,15 @@ xfs_close_devices(
 {
         if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp) {
                 struct block_device *logdev = mp->m_logdev_targp->bt_bdev;
-                xfs_free_buftarg(mp->m_logdev_targp);
+                xfs_free_buftarg(mp, mp->m_logdev_targp);
                 xfs_blkdev_put(logdev);
         }
         if (mp->m_rtdev_targp) {
                 struct block_device *rtdev = mp->m_rtdev_targp->bt_bdev;
-                xfs_free_buftarg(mp->m_rtdev_targp);
+                xfs_free_buftarg(mp, mp->m_rtdev_targp);
                 xfs_blkdev_put(rtdev);
         }
-        xfs_free_buftarg(mp->m_ddev_targp);
+        xfs_free_buftarg(mp, mp->m_ddev_targp);
 }
 
 /*
@@ -810,9 +810,9 @@ xfs_open_devices(
 
  out_free_rtdev_targ:
         if (mp->m_rtdev_targp)
-                xfs_free_buftarg(mp->m_rtdev_targp);
+                xfs_free_buftarg(mp, mp->m_rtdev_targp);
  out_free_ddev_targ:
-        xfs_free_buftarg(mp->m_ddev_targp);
+        xfs_free_buftarg(mp, mp->m_ddev_targp);
  out_close_rtdev:
         if (rtdev)
                 xfs_blkdev_put(rtdev);