1 files changed, 66 insertions, 0 deletions

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index 2302454d8d47..d2701cc624b9 100644
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -278,6 +278,72 @@ xfs_blkdev_put(
                 close_bdev_excl(bdev);
 }
 
+/*
+ * Try to write out the superblock using barriers.
+ */
+STATIC int
+xfs_barrier_test(
+        xfs_mount_t     *mp)
+{
+        xfs_buf_t       *sbp = xfs_getsb(mp, 0);
+        int             error;
+
+        XFS_BUF_UNDONE(sbp);
+        XFS_BUF_UNREAD(sbp);
+        XFS_BUF_UNDELAYWRITE(sbp);
+        XFS_BUF_WRITE(sbp);
+        XFS_BUF_UNASYNC(sbp);
+        XFS_BUF_ORDERED(sbp);
+
+        xfsbdstrat(mp, sbp);
+        error = xfs_iowait(sbp);
+
+        /*
+         * Clear all the flags we set and possible error state in the
+         * buffer.  We only did the write to try out whether barriers
+         * worked and shouldn't leave any traces in the superblock
+         * buffer.
+         */
+        XFS_BUF_DONE(sbp);
+        XFS_BUF_ERROR(sbp, 0);
+        XFS_BUF_UNORDERED(sbp);
+
+        xfs_buf_relse(sbp);
+        return error;
+}
+
+void
+xfs_mountfs_check_barriers(xfs_mount_t *mp)
+{
+        int error;
+
+        if (mp->m_logdev_targp != mp->m_ddev_targp) {
+                xfs_fs_cmn_err(CE_NOTE, mp,
+                  "Disabling barriers, not supported with external log device");
+                mp->m_flags &= ~XFS_MOUNT_BARRIER;
+        }
+
+        if (mp->m_ddev_targp->pbr_bdev->bd_disk->queue->ordered ==
+                                        QUEUE_ORDERED_NONE) {
+                xfs_fs_cmn_err(CE_NOTE, mp,
+                  "Disabling barriers, not supported by the underlying device");
+                mp->m_flags &= ~XFS_MOUNT_BARRIER;
+        }
+
+        error = xfs_barrier_test(mp);
+        if (error) {
+                xfs_fs_cmn_err(CE_NOTE, mp,
+                  "Disabling barriers, trial barrier write failed");
+                mp->m_flags &= ~XFS_MOUNT_BARRIER;
+        }
+}
+
+void
+xfs_blkdev_issue_flush(
+        xfs_buftarg_t           *buftarg)
+{
+        blkdev_issue_flush(buftarg->pbr_bdev, NULL);
+}
 
 STATIC struct inode *
 linvfs_alloc_inode(