GFS2: Remove localcaching mount option

This option defaulted to on for lock_nolock mounts and off
otherwise. The only function was to avoid the revalidation of
dentries. In the cluster case, that is entirely pointless and
liable to cause coherency problems.

The patch changes the revalidation to depend upon whether the
fs is a local or cluster fs (i.e. it follows the existing default
behaviour). I very much doubt anybody ever used this option as
there is no reason to. Even so we will continue to accept it
on the mount command line, but ignore it.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/dentry.c

@@ -49,7 +49,7 @@ static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
 		ip = GFS2_I(inode);
 	}
 
-	if (sdp->sd_args.ar_localcaching)
+	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
 		goto valid;
 
 	had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);

fs/gfs2/incore.h

@@ -417,7 +417,6 @@ struct gfs2_args {
 	char ar_hostdata[GFS2_LOCKNAME_LEN];	/* Host specific data */
 	unsigned int ar_spectator:1;		/* Don't get a journal */
 	unsigned int ar_localflocks:1;		/* Let the VFS do flock|fcntl */
-	unsigned int ar_localcaching:1;		/* Local caching */
 	unsigned int ar_debug:1;		/* Oops on errors */
 	unsigned int ar_upgrade:1;		/* Upgrade ondisk format */
 	unsigned int ar_posix_acl:1;		/* Enable posix acls */

fs/gfs2/ops_fstype.c

@@ -1022,7 +1022,6 @@ static int gfs2_lm_mount(struct gfs2_sbd *sdp, int silent)
 	if (!strcmp("lock_nolock", proto)) {
 		lm = &nolock_ops;
 		sdp->sd_args.ar_localflocks = 1;
-		sdp->sd_args.ar_localcaching = 1;
 #ifdef CONFIG_GFS2_FS_LOCKING_DLM
 	} else if (!strcmp("lock_dlm", proto)) {
 		lm = &gfs2_dlm_ops;

fs/gfs2/super.c

@@ -165,7 +165,7 @@ int gfs2_mount_args(struct gfs2_args *args, char *options)
 			args->ar_localflocks = 1;
 			break;
 		case Opt_localcaching:
-			args->ar_localcaching = 1;
+			/* Retained for backwards compat only */
 			break;
 		case Opt_debug:
 			if (args->ar_errors == GFS2_ERRORS_PANIC) {
@@ -1129,7 +1129,6 @@ static int gfs2_remount_fs(struct super_block *sb, int *flags, char *data)
 	/* Some flags must not be changed */
 	if (args_neq(&args, &sdp->sd_args, spectator) ||
 	    args_neq(&args, &sdp->sd_args, localflocks) ||
-	    args_neq(&args, &sdp->sd_args, localcaching) ||
 	    args_neq(&args, &sdp->sd_args, meta))
 		return -EINVAL;
 
@@ -1234,8 +1233,6 @@ static int gfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
 		seq_printf(s, ",spectator");
 	if (args->ar_localflocks)
 		seq_printf(s, ",localflocks");
-	if (args->ar_localcaching)
-		seq_printf(s, ",localcaching");
 	if (args->ar_debug)
 		seq_printf(s, ",debug");
 	if (args->ar_upgrade)