xfs: factor out forced iclog flushes

We force iclogs in several places - we need them all to have the
same cache flush semantics, so start by factoring out the iclog
force into a common helper.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index e8c6c96d4f7c83364c881fb76d5467c1d71ab430..184c68ea62bb57e98d0e74c96ad65d49facd1787 100644 (file)
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -778,6 +778,20 @@ xfs_log_mount_cancel(
        xfs_log_unmount(mp);
 }
 
+/*
+ * Flush out the iclog to disk ensuring that device caches are flushed and
+ * the iclog hits stable storage before any completion waiters are woken.
+ */
+static inline int
+xlog_force_iclog(
+       struct xlog_in_core     *iclog)
+{
+       atomic_inc(&iclog->ic_refcnt);
+       if (iclog->ic_state == XLOG_STATE_ACTIVE)
+               xlog_state_switch_iclogs(iclog->ic_log, iclog, 0);
+       return xlog_state_release_iclog(iclog->ic_log, iclog, 0);
+}
+
 /*
  * Wait for the iclog and all prior iclogs to be written disk as required by the
  * log force state machine. Waiting on ic_force_wait ensures iclog completions
@@ -863,18 +877,8 @@ out_err:
 
        spin_lock(&log->l_icloglock);
        iclog = log->l_iclog;
-       atomic_inc(&iclog->ic_refcnt);
-       if (iclog->ic_state == XLOG_STATE_ACTIVE)
-               xlog_state_switch_iclogs(log, iclog, 0);
-       else
-               ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC ||
-                      iclog->ic_state == XLOG_STATE_IOERROR);
-       /*
-        * Ensure the journal is fully flushed and on stable storage once the
-        * iclog containing the unmount record is written.
-        */
        iclog->ic_flags |= (XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA);
-       error = xlog_state_release_iclog(log, iclog, 0);
+       error = xlog_force_iclog(iclog);
        xlog_wait_on_iclog(iclog);
 
        if (tic) {
@@ -3201,17 +3205,9 @@ xfs_log_force(
                iclog = iclog->ic_prev;
        } else if (iclog->ic_state == XLOG_STATE_ACTIVE) {
                if (atomic_read(&iclog->ic_refcnt) == 0) {
-                       /*
-                        * We are the only one with access to this iclog.
-                        *
-                        * Flush it out now.  There should be a roundoff of zero
-                        * to show that someone has already taken care of the
-                        * roundoff from the previous sync.
-                        */
-                       atomic_inc(&iclog->ic_refcnt);
+                       /* We have exclusive access to this iclog. */
                        lsn = be64_to_cpu(iclog->ic_header.h_lsn);
-                       xlog_state_switch_iclogs(log, iclog, 0);
-                       if (xlog_state_release_iclog(log, iclog, 0))
+                       if (xlog_force_iclog(iclog))
                                goto out_error;
 
                        if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn)
@@ -3289,9 +3285,7 @@ xlog_force_lsn(
                                        &log->l_icloglock);
                        return -EAGAIN;
                }
-               atomic_inc(&iclog->ic_refcnt);
-               xlog_state_switch_iclogs(log, iclog, 0);
-               if (xlog_state_release_iclog(log, iclog, 0))
+               if (xlog_force_iclog(iclog))
                        goto out_error;
                if (log_flushed)
                        *log_flushed = 1;