[patch] remove unnecessary periodic superblock logging.

[David Chinner <dgc@xxxxxxx>]

Remove periodic logging of in-core superblock counters.

xfssyncd triggers the logging of superblock counters every
30s if the filesystem is made with lazy-count=1. This will
prevent disks from idling and spinning down as there will
be a log write every 30s. With the way counter recovery
works for lazy-count=1, this code is unnecessary and provides
no real benefit, so just remove it.

Signed-off-by: Dave Chinner <dgc@xxxxxxx>
---
 fs/xfs/linux-2.6/xfs_super.c |    3 +--
 fs/xfs/linux-2.6/xfs_vfs.h   |    1 -
 fs/xfs/xfs_vfsops.c          |   13 -------------
 3 files changed, 1 insertion(+), 16 deletions(-)

Index: 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_super.c
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/linux-2.6/xfs_super.c     2008-04-10 
10:02:14.000000000 +1000
+++ 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_super.c  2008-04-10 10:02:58.419346393 
+1000
@@ -1028,8 +1028,7 @@ xfs_sync_worker(
        int             error;
 
        if (!(mp->m_flags & XFS_MOUNT_RDONLY))
-               error = xfs_sync(mp, SYNC_FSDATA | SYNC_BDFLUSH | SYNC_ATTR |
-                                    SYNC_REFCACHE | SYNC_SUPER);
+               error = xfs_sync(mp, SYNC_FSDATA | SYNC_BDFLUSH | SYNC_ATTR);
        mp->m_sync_seq++;
        wake_up(&mp->m_wait_single_sync_task);
 }
Index: 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_vfs.h
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/linux-2.6/xfs_vfs.h       2008-04-10 
10:00:25.000000000 +1000
+++ 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_vfs.h    2008-04-10 10:02:58.419346393 
+1000
@@ -49,7 +49,6 @@ typedef struct bhv_vfs_sync_work {
 #define SYNC_REFCACHE          0x0040  /* prune some of the nfs ref cache */
 #define SYNC_REMOUNT           0x0080  /* remount readonly, no dummy LRs */
 #define SYNC_IOWAIT            0x0100  /* wait for all I/O to complete */
-#define SYNC_SUPER             0x0200  /* flush superblock to disk */
 
 /*
  * When remounting a filesystem read-only or freezing the filesystem,
Index: 2.6.x-xfs-new/fs/xfs/xfs_vfsops.c
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/xfs_vfsops.c      2008-04-10 10:01:54.000000000 
+1000
+++ 2.6.x-xfs-new/fs/xfs/xfs_vfsops.c   2008-04-10 10:03:35.288729547 +1000
@@ -1326,21 +1326,8 @@ xfs_syncsub(
        }
 
        /*
-        * If asked, update the disk superblock with incore counter values if we
-        * are using non-persistent counters so that they don't get too far out
-        * of sync if we crash or get a forced shutdown. We don't want to force
-        * this to disk, just get a transaction into the iclogs....
-        */
-       if (flags & SYNC_SUPER) {
-               error = xfs_log_sbcount(mp, 0);
-               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)) {
                xfs_trans_t *tp;
                xfs_inode_t *ip;