[XFS] Kill xfs_sync()

There are no more callers to xfs_sync() now, so remove the function
altogther.

SGI-PV: 988140

SGI-Modid: xfs-linux-melb:xfs-kern:32311a

Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>

1 files changed, 15 insertions, 117 deletions

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 91a54a79a09b..ed24435af651 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -316,11 +316,21 @@ xfs_sync_fsdata(
 }
 
 /*
- * First stage of freeze - no more writers will make progress now we are here,
+ * When remounting a filesystem read-only or freezing the filesystem, we have
+ * two phases to execute. This first phase is syncing the data before we
+ * quiesce the filesystem, and the second is flushing all the inodes out after
+ * we've waited for all the transactions created by the first phase to
+ * complete. The second phase ensures that the inodes are written to their
+ * location on disk rather than just existing in transactions in the log. This
+ * means after a quiesce there is no log replay required to write the inodes to
+ * disk (this is the main difference between a sync and a quiesce).
+ */
+/*
+ * First stage of freeze - no writers will make progress now we are here,
  * so we flush delwri and delalloc buffers here, then wait for all I/O to
  * complete.  Data is frozen at that point. Metadata is not frozen,
- * transactions can still occur here so don't bother flushing the buftarg (i.e
- * SYNC_QUIESCE) because it'll just get dirty again.
+ * transactions can still occur here so don't bother flushing the buftarg
+ * because it'll just get dirty again.
  */
 int
 xfs_quiesce_data(
@@ -337,11 +347,10 @@ xfs_quiesce_data(
         xfs_sync_inodes(mp, SYNC_DELWRI|SYNC_WAIT|SYNC_IOWAIT);
         XFS_QM_DQSYNC(mp, SYNC_WAIT);
 
-        /* write superblock and hoover shutdown errors */
+        /* write superblock and hoover up shutdown errors */
         error = xfs_sync_fsdata(mp, 0);
 
-        /* flush devices */
-        XFS_bflush(mp->m_ddev_targp);
+        /* flush data-only devices */
         if (mp->m_rtdev_targp)
                 XFS_bflush(mp->m_rtdev_targp);
 
@@ -349,117 +358,6 @@ xfs_quiesce_data(
 }
 
 /*
- * xfs_sync flushes any pending I/O to file system vfsp.
- *
- * This routine is called by vfs_sync() to make sure that things make it
- * out to disk eventually, on sync() system calls to flush out everything,
- * and when the file system is unmounted.  For the vfs_sync() case, all
- * we really need to do is sync out the log to make all of our meta-data
- * updates permanent (except for timestamps).  For calls from pflushd(),
- * dirty pages are kept moving by calling pdflush() on the inodes
- * containing them.  We also flush the inodes that we can lock without
- * sleeping and the superblock if we can lock it without sleeping from
- * vfs_sync() so that items at the tail of the log are always moving out.
- *
- * Flags:
- *      SYNC_BDFLUSH - We're being called from vfs_sync() so we don't want
- *                     to sleep if we can help it.  All we really need
- *                     to do is ensure that the log is synced at least
- *                     periodically.  We also push the inodes and
- *                     superblock if we can lock them without sleeping
- *                      and they are not pinned.
- *      SYNC_ATTR    - We need to flush the inodes. Now handled by direct calls
- *                     to xfs_sync_inodes().
- *      SYNC_WAIT    - All the flushes that take place in this call should
- *                     be synchronous.
- *      SYNC_DELWRI  - This tells us to push dirty pages associated with
- *                     inodes.  SYNC_WAIT and SYNC_BDFLUSH are used to
- *                     determine if they should be flushed sync, async, or
- *                     delwri.
- *      SYNC_FSDATA  - This indicates that the caller would like to make
- *                     sure the superblock is safe on disk.  We can ensure
- *                     this by simply making sure the log gets flushed
- *                     if SYNC_BDFLUSH is set, and by actually writing it
- *                     out otherwise.
- *      SYNC_IOWAIT  - The caller wants us to wait for all data I/O to complete
- *                     before we return (including direct I/O). Forms the drain
- *                     side of the write barrier needed to safely quiesce the
- *                     filesystem.
- *
- */
-int
-xfs_sync(
-        xfs_mount_t     *mp,
-        int             flags)
-{
-        int             error;
-        int             last_error = 0;
-        uint            log_flags = XFS_LOG_FORCE;
-
-        ASSERT(!(flags & SYNC_ATTR));
-
-        /*
-         * Get the Quota Manager to flush the dquots.
-         *
-         * If XFS quota support is not enabled or this filesystem
-         * instance does not use quotas XFS_QM_DQSYNC will always
-         * return zero.
-         */
-        error = XFS_QM_DQSYNC(mp, flags);
-        if (error) {
-                /*
-                 * If we got an IO error, we will be shutting down.
-                 * So, there's nothing more for us to do here.
-                 */
-                ASSERT(error != EIO || XFS_FORCED_SHUTDOWN(mp));
-                if (XFS_FORCED_SHUTDOWN(mp))
-                        return XFS_ERROR(error);
-        }
-
-        if (flags & SYNC_IOWAIT)
-                xfs_filestream_flush(mp);
-
-        /*
-         * Sync out the log.  This ensures that the log is periodically
-         * flushed even if there is not enough activity to fill it up.
-         */
-        if (flags & SYNC_WAIT)
-                log_flags |= XFS_LOG_SYNC;
-
-        xfs_log_force(mp, (xfs_lsn_t)0, log_flags);
-
-        if (flags & SYNC_DELWRI) {
-                if (flags & SYNC_BDFLUSH)
-                        xfs_finish_reclaim_all(mp, 1, XFS_IFLUSH_DELWRI_ELSE_ASYNC);
-                else
-                        error = xfs_sync_inodes(mp, flags);
-                /*
-                 * Flushing out dirty data above probably generated more
-                 * log activity, so if this isn't vfs_sync() then flush
-                 * the log again.
-                 */
-                xfs_log_force(mp, 0, log_flags);
-        }
-
-        if (flags & SYNC_FSDATA) {
-                error = xfs_sync_fsdata(mp, flags);
-                if (error)
-                        last_error = error;
-        }
-
-        /*
-         * Now check to see if the log needs a "dummy" transaction.
-         */
-        if (!(flags & SYNC_REMOUNT) && xfs_log_need_covered(mp)) {
-                error = xfs_commit_dummy_trans(mp, log_flags);
-                if (error)
-                        return error;
-        }
-
-        return XFS_ERROR(last_error);
-}
-
-/*
  * Enqueue a work item to be picked up by the vfs xfssyncd thread.
  * Doing this has two advantages:
  * - It saves on stack space, which is tight in certain situations