12 files changed, 190 insertions, 59 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 188cbbd5b74a..4663f7dbff1c 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -1295,6 +1295,11 @@ _pagebuf_ioapply(
                 rw = (pb->pb_flags & PBF_READ) ? READ : WRITE;
         }
 
+        if (pb->pb_flags & PBF_ORDERED) {
+                ASSERT(!(pb->pb_flags & PBF_READ));
+                rw = WRITE_BARRIER;
+        }
+
         /* Special code path for reading a sub page size pagebuf in --
          * we populate up the whole page, and hence the other metadata
          * in the same page.  This optimization is only valid when the
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index 39c8ca122534..fa21d1f9cb0b 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -74,7 +74,7 @@ typedef enum page_buf_flags_e {		/* pb_flags values */
         PBF_DELWRI = (1 << 6),  /* buffer has dirty pages                  */
         PBF_STALE = (1 << 7),   /* buffer has been staled, do not find it  */
         PBF_FS_MANAGED = (1 << 8),  /* filesystem controls freeing memory  */
-        PBF_FLUSH = (1 << 11),      /* flush disk write cache              */
+        PBF_ORDERED = (1 << 11),    /* use ordered writes                  */
         PBF_READ_AHEAD = (1 << 12), /* asynchronous read-ahead             */
 
         /* flags used only as arguments to access routines */
@@ -383,9 +383,9 @@ extern void pagebuf_trace(
 #define XFS_BUF_UNASYNC(x)       ((x)->pb_flags &= ~PBF_ASYNC)
 #define XFS_BUF_ISASYNC(x)       ((x)->pb_flags & PBF_ASYNC)
 
-#define XFS_BUF_FLUSH(x)         ((x)->pb_flags |= PBF_FLUSH)
-#define XFS_BUF_UNFLUSH(x)       ((x)->pb_flags &= ~PBF_FLUSH)
-#define XFS_BUF_ISFLUSH(x)       ((x)->pb_flags & PBF_FLUSH)
+#define XFS_BUF_ORDERED(x)       ((x)->pb_flags |= PBF_ORDERED)
+#define XFS_BUF_UNORDERED(x)     ((x)->pb_flags &= ~PBF_ORDERED)
+#define XFS_BUF_ISORDERED(x)     ((x)->pb_flags & PBF_ORDERED)
 
 #define XFS_BUF_SHUT(x)          printk("XFS_BUF_SHUT not implemented yet\n")
 #define XFS_BUF_UNSHUT(x)        printk("XFS_BUF_UNSHUT not implemented yet\n")
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(
diff --git a/fs/xfs/linux-2.6/xfs_super.h b/fs/xfs/linux-2.6/xfs_super.h
index ec7e0035c731..ad77e3743e04 100644
--- a/fs/xfs/linux-2.6/xfs_super.h
+++ b/fs/xfs/linux-2.6/xfs_super.h
@@ -132,6 +132,7 @@ extern void xfs_flush_device(struct xfs_inode *);
 extern int  xfs_blkdev_get(struct xfs_mount *, const char *,
                                 struct block_device **);
 extern void xfs_blkdev_put(struct block_device *);
+extern void xfs_blkdev_issue_flush(struct xfs_buftarg *);
 
 extern struct export_operations linvfs_export_ops;
 
diff --git a/fs/xfs/xfs_clnt.h b/fs/xfs/xfs_clnt.h
index b3215ffe0be8..c93cb282f3d8 100644
--- a/fs/xfs/xfs_clnt.h
+++ b/fs/xfs/xfs_clnt.h
@@ -99,7 +99,7 @@ struct xfs_mount_args {
                                                  * enforcement */
 #define XFSMNT_NOUUID           0x01000000      /* Ignore fs uuid */
 #define XFSMNT_DMAPI            0x02000000      /* enable dmapi/xdsm */
-#define XFSMNT_NOLOGFLUSH       0x04000000      /* Don't flush for log blocks */
+#define XFSMNT_BARRIER          0x04000000      /* use write barriers */
 #define XFSMNT_IDELETE          0x08000000      /* inode cluster delete */
 #define XFSMNT_SWALLOC          0x10000000      /* turn on stripe width
                                                  * allocation */
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 51814c32eddf..b9d3ad35240e 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -93,8 +93,11 @@ STATIC int  xlog_state_release_iclog(xlog_t		*log,
 STATIC void xlog_state_switch_iclogs(xlog_t             *log,
                                      xlog_in_core_t *iclog,
                                      int                eventual_size);
-STATIC int  xlog_state_sync(xlog_t *log, xfs_lsn_t lsn, uint flags);
-STATIC int  xlog_state_sync_all(xlog_t *log, uint flags);
+STATIC int  xlog_state_sync(xlog_t                      *log,
+                            xfs_lsn_t                   lsn,
+                            uint                        flags,
+                            int                         *log_flushed);
+STATIC int  xlog_state_sync_all(xlog_t *log, uint flags, int *log_flushed);
 STATIC void xlog_state_want_sync(xlog_t *log, xlog_in_core_t *iclog);
 
 /* local functions to manipulate grant head */
@@ -312,12 +315,17 @@ xfs_log_done(xfs_mount_t	*mp,
  * semaphore.
  */
 int
-xfs_log_force(xfs_mount_t *mp,
-              xfs_lsn_t   lsn,
-              uint        flags)
+_xfs_log_force(
+        xfs_mount_t     *mp,
+        xfs_lsn_t       lsn,
+        uint            flags,
+        int             *log_flushed)
 {
-        int     rval;
-        xlog_t *log = mp->m_log;
+        xlog_t          *log = mp->m_log;
+        int             dummy;
+
+        if (!log_flushed)
+                log_flushed = &dummy;
 
 #if defined(DEBUG) || defined(XLOG_NOLOG)
         if (!xlog_debug && xlog_target == log->l_targ)
@@ -328,17 +336,12 @@ xfs_log_force(xfs_mount_t *mp,
 
         XFS_STATS_INC(xs_log_force);
 
-        if ((log->l_flags & XLOG_IO_ERROR) == 0) {
-                if (lsn == 0)
-                        rval = xlog_state_sync_all(log, flags);
-                else
-                        rval = xlog_state_sync(log, lsn, flags);
-        } else {
-                rval = XFS_ERROR(EIO);
-        }
-
-        return rval;
-
+        if (log->l_flags & XLOG_IO_ERROR)
+                return XFS_ERROR(EIO);
+        if (lsn == 0)
+                return xlog_state_sync_all(log, flags, log_flushed);
+        else
+                return xlog_state_sync(log, lsn, flags, log_flushed);
 }       /* xfs_log_force */
 
 /*
@@ -1467,14 +1470,13 @@ xlog_sync(xlog_t		*log,
         XFS_BUF_BUSY(bp);
         XFS_BUF_ASYNC(bp);
         /*
-         * Do a disk write cache flush for the log block.
-         * This is a bit of a sledgehammer, it would be better
-         * to use a tag barrier here that just prevents reordering.
+         * Do an ordered write for the log block.
+         *
          * It may not be needed to flush the first split block in the log wrap
          * case, but do it anyways to be safe -AK
          */
-        if (!(log->l_mp->m_flags & XFS_MOUNT_NOLOGFLUSH))
-                XFS_BUF_FLUSH(bp);
+        if (log->l_mp->m_flags & XFS_MOUNT_BARRIER)
+                XFS_BUF_ORDERED(bp);
 
         ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
         ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);
@@ -1505,8 +1507,8 @@ xlog_sync(xlog_t		*log,
                 XFS_BUF_SET_FSPRIVATE(bp, iclog);
                 XFS_BUF_BUSY(bp);
                 XFS_BUF_ASYNC(bp);
-                if (!(log->l_mp->m_flags & XFS_MOUNT_NOLOGFLUSH))
-                        XFS_BUF_FLUSH(bp);
+                if (log->l_mp->m_flags & XFS_MOUNT_BARRIER)
+                        XFS_BUF_ORDERED(bp);
                 dptr = XFS_BUF_PTR(bp);
                 /*
                  * Bump the cycle numbers at the start of each block
@@ -2951,7 +2953,7 @@ xlog_state_switch_iclogs(xlog_t		*log,
  *              not in the active nor dirty state.
  */
 STATIC int
-xlog_state_sync_all(xlog_t *log, uint flags)
+xlog_state_sync_all(xlog_t *log, uint flags, int *log_flushed)
 {
         xlog_in_core_t  *iclog;
         xfs_lsn_t       lsn;
@@ -3000,6 +3002,7 @@ xlog_state_sync_all(xlog_t *log, uint flags)
 
                                 if (xlog_state_release_iclog(log, iclog))
                                         return XFS_ERROR(EIO);
+                                *log_flushed = 1;
                                 s = LOG_LOCK(log);
                                 if (INT_GET(iclog->ic_header.h_lsn, ARCH_CONVERT) == lsn &&
                                     iclog->ic_state != XLOG_STATE_DIRTY)
@@ -3043,6 +3046,7 @@ maybe_sleep:
                  */
                 if (iclog->ic_state & XLOG_STATE_IOERROR)
                         return XFS_ERROR(EIO);
+                *log_flushed = 1;
 
         } else {
 
@@ -3068,7 +3072,8 @@ no_sleep:
 int
 xlog_state_sync(xlog_t    *log,
                 xfs_lsn_t lsn,
-                uint      flags)
+                uint      flags,
+                int       *log_flushed)
 {
     xlog_in_core_t      *iclog;
     int                 already_slept = 0;
@@ -3120,6 +3125,7 @@ try_again:
                         XFS_STATS_INC(xs_log_force_sleep);
                         sv_wait(&iclog->ic_prev->ic_writesema, PSWP,
                                 &log->l_icloglock, s);
+                        *log_flushed = 1;
                         already_slept = 1;
                         goto try_again;
                 } else {
@@ -3128,6 +3134,7 @@ try_again:
                         LOG_UNLOCK(log, s);
                         if (xlog_state_release_iclog(log, iclog))
                                 return XFS_ERROR(EIO);
+                        *log_flushed = 1;
                         s = LOG_LOCK(log);
                 }
         }
@@ -3152,6 +3159,7 @@ try_again:
                  */
                 if (iclog->ic_state & XLOG_STATE_IOERROR)
                         return XFS_ERROR(EIO);
+                *log_flushed = 1;
         } else {                /* just return */
                 LOG_UNLOCK(log, s);
         }
@@ -3606,6 +3614,7 @@ xfs_log_force_umount(
         xlog_ticket_t   *tic;
         xlog_t          *log;
         int             retval;
+        int             dummy;
         SPLDECL(s);
         SPLDECL(s2);
 
@@ -3684,7 +3693,7 @@ xfs_log_force_umount(
                  * Force the incore logs to disk before shutting the
                  * log down completely.
                  */
-                xlog_state_sync_all(log, XFS_LOG_FORCE|XFS_LOG_SYNC);
+                xlog_state_sync_all(log, XFS_LOG_FORCE|XFS_LOG_SYNC, &dummy);
                 s2 = LOG_LOCK(log);
                 retval = xlog_state_ioerror(log);
                 LOG_UNLOCK(log, s2);
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,
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 5affba38a577..bc55931ac74e 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -415,7 +415,7 @@ typedef struct xfs_mount {
                                                  * 32 bits in size */
 #define XFS_MOUNT_32BITINOOPT   0x00008000      /* saved mount option state */
 #define XFS_MOUNT_NOUUID        0x00010000      /* ignore uuid during mount */
-#define XFS_MOUNT_NOLOGFLUSH    0x00020000
+#define XFS_MOUNT_BARRIER       0x00020000
 #define XFS_MOUNT_IDELETE       0x00040000      /* delete empty inode clusters*/
 #define XFS_MOUNT_SWALLOC       0x00080000      /* turn on stripe width
                                                  * allocation */
@@ -542,6 +542,7 @@ extern xfs_mount_t *xfs_mount_init(void);
 extern void     xfs_mod_sb(xfs_trans_t *, __int64_t);
 extern void     xfs_mount_free(xfs_mount_t *mp, int remove_bhv);
 extern int      xfs_mountfs(struct vfs *, xfs_mount_t *mp, int);
+extern void     xfs_mountfs_check_barriers(xfs_mount_t *mp);
 
 extern int      xfs_unmountfs(xfs_mount_t *, struct cred *);
 extern void     xfs_unmountfs_close(xfs_mount_t *, struct cred *);
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 92efe272b83d..5e33891b8049 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -661,10 +661,11 @@ xfs_trans_unreserve_and_mod_sb(
  */
  /*ARGSUSED*/
 int
-xfs_trans_commit(
+_xfs_trans_commit(
         xfs_trans_t     *tp,
         uint            flags,
-        xfs_lsn_t       *commit_lsn_p)
+        xfs_lsn_t       *commit_lsn_p,
+        int             *log_flushed)
 {
         xfs_log_iovec_t         *log_vector;
         int                     nvec;
@@ -893,9 +894,11 @@ shut_us_down:
          * log out now and wait for it.
          */
         if (sync) {
-                if (!error)
-                        error = xfs_log_force(mp, commit_lsn,
-                                      XFS_LOG_FORCE | XFS_LOG_SYNC);
+                if (!error) {
+                        error = _xfs_log_force(mp, commit_lsn,
+                                      XFS_LOG_FORCE | XFS_LOG_SYNC,
+                                      log_flushed);
+                }
                 XFS_STATS_INC(xs_trans_sync);
         } else {
                 XFS_STATS_INC(xs_trans_async);
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index a263aec8b3a6..0cc7af5c1f00 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -1025,7 +1025,12 @@ void		xfs_trans_log_efd_extent(xfs_trans_t *,
                                          struct xfs_efd_log_item *,
                                          xfs_fsblock_t,
                                          xfs_extlen_t);
-int             xfs_trans_commit(xfs_trans_t *, uint flags, xfs_lsn_t *);
+int             _xfs_trans_commit(xfs_trans_t *,
+                                  uint flags,
+                                  xfs_lsn_t *,
+                                  int *);
+#define xfs_trans_commit(tp, flags, lsn) \
+        _xfs_trans_commit(tp, flags, lsn, NULL)
 void            xfs_trans_cancel(xfs_trans_t *, int);
 void            xfs_trans_ail_init(struct xfs_mount *);
 xfs_lsn_t       xfs_trans_push_ail(struct xfs_mount *, xfs_lsn_t);
diff --git a/fs/xfs/xfs_vfsops.c b/fs/xfs/xfs_vfsops.c
index f1a904e23ade..8238c7517822 100644
--- a/fs/xfs/xfs_vfsops.c
+++ b/fs/xfs/xfs_vfsops.c
@@ -321,8 +321,8 @@ xfs_start_flags(
 
         if (ap->flags & XFSMNT_NOUUID)
                 mp->m_flags |= XFS_MOUNT_NOUUID;
-        if (ap->flags & XFSMNT_NOLOGFLUSH)
-                mp->m_flags |= XFS_MOUNT_NOLOGFLUSH;
+        if (ap->flags & XFSMNT_BARRIER)
+                mp->m_flags |= XFS_MOUNT_BARRIER;
 
         return 0;
 }
@@ -512,8 +512,14 @@ xfs_mount(
                 goto error2;
 
         error = XFS_IOINIT(vfsp, args, flags);
-        if (!error)
-                return 0;
+        if (error)
+                goto error2;
+
+        if ((args->flags & XFSMNT_BARRIER) &&
+            !(XFS_MTOVFS(mp)->vfs_flag & VFS_RDONLY))
+                xfs_mountfs_check_barriers(mp);
+        return 0;
+
 error2:
         if (mp->m_sb_bp)
                 xfs_freesb(mp);
@@ -656,19 +662,24 @@ xfs_mntupdate(
         else
                 mp->m_flags &= ~XFS_MOUNT_NOATIME;
 
-        if (!(vfsp->vfs_flag & VFS_RDONLY)) {
-                VFS_SYNC(vfsp, SYNC_FSDATA|SYNC_BDFLUSH|SYNC_ATTR, NULL, error);
+        if ((vfsp->vfs_flag & VFS_RDONLY) &&
+            !(*flags & MS_RDONLY)) {
+                vfsp->vfs_flag &= ~VFS_RDONLY;
+
+                if (args->flags & XFSMNT_BARRIER)
+                        xfs_mountfs_check_barriers(mp);
         }
 
-        if (*flags & MS_RDONLY) {
+        if (!(vfsp->vfs_flag & VFS_RDONLY) &&
+            (*flags & MS_RDONLY)) {
+                VFS_SYNC(vfsp, SYNC_FSDATA|SYNC_BDFLUSH|SYNC_ATTR, NULL, error);
+
                 xfs_quiesce_fs(mp);
 
                 /* Ok now write out an unmount record */
                 xfs_log_unmount_write(mp);
                 xfs_unmountfs_writesb(mp);
                 vfsp->vfs_flag |= VFS_RDONLY;
-        } else {
-                vfsp->vfs_flag &= ~VFS_RDONLY;
         }
 
         return 0;
@@ -1628,7 +1639,8 @@ xfs_vget(
 #define MNTOPT_ALLOCSIZE    "allocsize"    /* preferred allocation size */
 #define MNTOPT_IHASHSIZE    "ihashsize"    /* size of inode hash table */
 #define MNTOPT_NORECOVERY   "norecovery"   /* don't run XFS recovery */
-#define MNTOPT_NOLOGFLUSH   "nologflush"   /* don't hard flush on log writes */
+#define MNTOPT_BARRIER  "barrier"       /* use writer barriers for log write and
+                                           unwritten extent conversion */
 #define MNTOPT_OSYNCISOSYNC "osyncisosync" /* o_sync is REALLY o_sync */
 #define MNTOPT_64BITINODE   "inode64"   /* inodes can be allocated anywhere */
 #define MNTOPT_IKEEP    "ikeep"         /* do not free empty inode clusters */
@@ -1791,8 +1803,8 @@ xfs_parseargs(
 #endif
                 } else if (!strcmp(this_char, MNTOPT_NOUUID)) {
                         args->flags |= XFSMNT_NOUUID;
-                } else if (!strcmp(this_char, MNTOPT_NOLOGFLUSH)) {
-                        args->flags |= XFSMNT_NOLOGFLUSH;
+                } else if (!strcmp(this_char, MNTOPT_BARRIER)) {
+                        args->flags |= XFSMNT_BARRIER;
                 } else if (!strcmp(this_char, MNTOPT_IKEEP)) {
                         args->flags &= ~XFSMNT_IDELETE;
                 } else if (!strcmp(this_char, MNTOPT_NOIKEEP)) {
@@ -1866,7 +1878,7 @@ xfs_showargs(
                 { XFS_MOUNT_NOUUID,             "," MNTOPT_NOUUID },
                 { XFS_MOUNT_NORECOVERY,         "," MNTOPT_NORECOVERY },
                 { XFS_MOUNT_OSYNCISOSYNC,       "," MNTOPT_OSYNCISOSYNC },
-                { XFS_MOUNT_NOLOGFLUSH,         "," MNTOPT_NOLOGFLUSH },
+                { XFS_MOUNT_BARRIER,            "," MNTOPT_BARRIER },
                 { XFS_MOUNT_IDELETE,            "," MNTOPT_NOIKEEP },
                 { 0, NULL }
         };
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 58bfe629b933..e2bf2ef58b66 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -1118,6 +1118,7 @@ xfs_fsync(
         xfs_inode_t     *ip;
         xfs_trans_t     *tp;
         int             error;
+        int             log_flushed = 0, changed = 1;
 
         vn_trace_entry(BHV_TO_VNODE(bdp),
                         __FUNCTION__, (inst_t *)__return_address);
@@ -1171,10 +1172,18 @@ xfs_fsync(
                 xfs_iunlock(ip, XFS_ILOCK_SHARED);
 
                 if (xfs_ipincount(ip)) {
-                        xfs_log_force(ip->i_mount, (xfs_lsn_t)0,
+                        _xfs_log_force(ip->i_mount, (xfs_lsn_t)0,
                                       XFS_LOG_FORCE |
                                       ((flag & FSYNC_WAIT)
-                                       ? XFS_LOG_SYNC : 0));
+                                       ? XFS_LOG_SYNC : 0),
+                                      &log_flushed);
+                } else {
+                        /*
+                         * If the inode is not pinned and nothing
+                         * has changed we don't need to flush the
+                         * cache.
+                         */
+                        changed = 0;
                 }
                 error = 0;
         } else  {
@@ -1210,10 +1219,27 @@ xfs_fsync(
                 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
                 if (flag & FSYNC_WAIT)
                         xfs_trans_set_sync(tp);
-                error = xfs_trans_commit(tp, 0, NULL);
+                error = _xfs_trans_commit(tp, 0, NULL, &log_flushed);
 
                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
         }
+
+        if ((ip->i_mount->m_flags & XFS_MOUNT_BARRIER) && changed) {
+                /*
+                 * If the log write didn't issue an ordered tag we need
+                 * to flush the disk cache for the data device now.
+                 */
+                if (!log_flushed)
+                        xfs_blkdev_issue_flush(ip->i_mount->m_ddev_targp);
+
+                /*
+                 * If this inode is on the RT dev we need to flush that
+                 * cache aswell.
+                 */
+                if (ip->i_d.di_flags & XFS_DIFLAG_REALTIME)
+                        xfs_blkdev_issue_flush(ip->i_mount->m_rtdev_targp);
+        }
+
         return error;
 }