[PATCH V2] make inode reclaim synchronise with xfs_iflush_done()

[Lachlan McIlroy <lachlan@xxxxxxx>]

On a forced shutdown, xfs_finish_reclaim() will skip flushing the inode.
If the inode flush lock is not already held and there is an outstanding
xfs_iflush_done() then we might free the inode prematurely.  By acquiring
and releasing the flush lock we will synchronise with xfs_iflush_done().

Lachlan

--- fs/xfs/xfs_vnodeops.c_1.727 2008-01-10 16:00:48.000000000 +1100
+++ fs/xfs/xfs_vnodeops.c       2008-02-07 15:15:26.000000000 +1100
@@ -3721,12 +3721,12 @@ xfs_finish_reclaim(
         * We get the flush lock regardless, though, just to make sure
         * we don't free it while it is being flushed.
         */
-       if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
-               if (!locked) {
-                       xfs_ilock(ip, XFS_ILOCK_EXCL);
-                       xfs_iflock(ip);
-               }
+       if (!locked) {
+               xfs_ilock(ip, XFS_ILOCK_EXCL);
+               xfs_iflock(ip);
+       }

+       if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
                if (ip->i_update_core ||
                    ((ip->i_itemp != NULL) &&
                     (ip->i_itemp->ili_format.ilf_fields != 0))) {
@@ -3746,17 +3746,11 @@ xfs_finish_reclaim(
                ASSERT(ip->i_update_core == 0);
                ASSERT(ip->i_itemp == NULL ||
                       ip->i_itemp->ili_format.ilf_fields == 0);
-               xfs_iunlock(ip, XFS_ILOCK_EXCL);
-       } else if (locked) {
-               /*
-                * We are not interested in doing an iflush if we're
-                * in the process of shutting down the filesystem forcibly.
-                * So, just reclaim the inode.
-                */
-               xfs_ifunlock(ip);
-               xfs_iunlock(ip, XFS_ILOCK_EXCL);
        }

+       xfs_ifunlock(ip);
+       xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
  reclaim:
        xfs_ireclaim(ip);
        return 0;