xfs: replace barriers with explicit flush / FUA usage

Switch to the WRITE_FLUSH_FUA flag for log writes and remove the EOPNOTSUPP
detection for barriers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

4 files changed, 3 insertions, 38 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index ea79072f5210..b93ea3342281 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -929,19 +929,7 @@ xfs_buf_iodone_work(
         xfs_buf_t               *bp =
                 container_of(work, xfs_buf_t, b_iodone_work);
 
-        /*
-         * We can get an EOPNOTSUPP to ordered writes.  Here we clear the
-         * ordered flag and reissue them.  Because we can't tell the higher
-         * layers directly that they should not issue ordered I/O anymore, they
-         * need to check if the _XFS_BARRIER_FAILED flag was set during I/O completion.
-         */
-        if ((bp->b_error == EOPNOTSUPP) &&
-            (bp->b_flags & (XBF_ORDERED|XBF_ASYNC)) == (XBF_ORDERED|XBF_ASYNC)) {
-                trace_xfs_buf_ordered_retry(bp, _RET_IP_);
-                bp->b_flags &= ~XBF_ORDERED;
-                bp->b_flags |= _XFS_BARRIER_FAILED;
-                xfs_buf_iorequest(bp);
-        } else if (bp->b_iodone)
+        if (bp->b_iodone)
                 (*(bp->b_iodone))(bp);
         else if (bp->b_flags & XBF_ASYNC)
                 xfs_buf_relse(bp);
@@ -1200,7 +1188,7 @@ _xfs_buf_ioapply(
 
         if (bp->b_flags & XBF_ORDERED) {
                 ASSERT(!(bp->b_flags & XBF_READ));
-                rw = WRITE_BARRIER;
+                rw = WRITE_FLUSH_FUA;
         } else if (bp->b_flags & XBF_LOG_BUFFER) {
                 ASSERT(!(bp->b_flags & XBF_READ_AHEAD));
                 bp->b_flags &= ~_XBF_RUN_QUEUES;
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index d072e5ff923b..d533d64e2c3e 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -86,14 +86,6 @@ typedef enum {
  */
 #define _XBF_PAGE_LOCKED        (1 << 22)
 
-/*
- * If we try a barrier write, but it fails we have to communicate
- * this to the upper layers.  Unfortunately b_error gets overwritten
- * when the buffer is re-issued so we have to add another flag to
- * keep this information.
- */
-#define _XFS_BARRIER_FAILED     (1 << 23)
-
 typedef unsigned int xfs_buf_flags_t;
 
 #define XFS_BUF_FLAGS \
@@ -114,8 +106,7 @@ typedef unsigned int xfs_buf_flags_t;
         { _XBF_PAGES,           "PAGES" }, \
         { _XBF_RUN_QUEUES,      "RUN_QUEUES" }, \
         { _XBF_DELWRI_Q,        "DELWRI_Q" }, \
-        { _XBF_PAGE_LOCKED,     "PAGE_LOCKED" }, \
-        { _XFS_BARRIER_FAILED,  "BARRIER_FAILED" }
+        { _XBF_PAGE_LOCKED,     "PAGE_LOCKED" }
 
 
 typedef enum {
diff --git a/fs/xfs/linux-2.6/xfs_trace.h b/fs/xfs/linux-2.6/xfs_trace.h
index be5dffd282a1..8fe311a456e2 100644
--- a/fs/xfs/linux-2.6/xfs_trace.h
+++ b/fs/xfs/linux-2.6/xfs_trace.h
@@ -325,7 +325,6 @@ DEFINE_BUF_EVENT(xfs_buf_lock);
 DEFINE_BUF_EVENT(xfs_buf_lock_done);
 DEFINE_BUF_EVENT(xfs_buf_cond_lock);
 DEFINE_BUF_EVENT(xfs_buf_unlock);
-DEFINE_BUF_EVENT(xfs_buf_ordered_retry);
 DEFINE_BUF_EVENT(xfs_buf_iowait);
 DEFINE_BUF_EVENT(xfs_buf_iowait_done);
 DEFINE_BUF_EVENT(xfs_buf_delwri_queue);
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 925d572bf0f4..430a8fc02c1f 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -917,19 +917,6 @@ xlog_iodone(xfs_buf_t *bp)
         l = iclog->ic_log;
 
         /*
-         * If the _XFS_BARRIER_FAILED flag was set by a lower
-         * layer, it means the underlying device no longer supports
-         * barrier I/O. Warn loudly and turn off barriers.
-         */
-        if (bp->b_flags & _XFS_BARRIER_FAILED) {
-                bp->b_flags &= ~_XFS_BARRIER_FAILED;
-                l->l_mp->m_flags &= ~XFS_MOUNT_BARRIER;
-                xfs_fs_cmn_err(CE_WARN, l->l_mp,
-                                "xlog_iodone: Barriers are no longer supported"
-                                " by device. Disabling barriers\n");
-        }
-
-        /*
          * Race to shutdown the filesystem if we see an error.
          */
         if (XFS_TEST_ERROR((XFS_BUF_GETERROR(bp)), l->l_mp,