GFS2: add barrier/nobarrier mount options

Currently gfs2 issues barrier unconditionally.  There are various reasons
to disable them, be that just for testing or for stupid devices flushing
large battert backed caches.  Add a nobarrier option that matches xfs and
btrfs for this.  Also add a symmetric barrier option to turn it back on
at remount time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index c239b0f..4792200 100644 (file)
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -429,6 +429,7 @@ struct gfs2_args {
        unsigned int ar_meta:1;                 /* mount metafs */
        unsigned int ar_discard:1;              /* discard requests */
        unsigned int ar_errors:2;               /* errors=withdraw | panic */
+       unsigned int ar_nobarrier:1;            /* do not send barriers */
        int ar_commit;                          /* Commit interval */
        int ar_statfs_quantum;                  /* The fast statfs interval */
        int ar_quota_quantum;                   /* The quota interval */

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 9744ee9..edfee24 100644 (file)
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1131,6 +1131,8 @@ static int fill_super(struct super_block *sb, struct gfs2_args *args, int silent
        }
        if (sdp->sd_args.ar_posix_acl)
                sb->s_flags |= MS_POSIXACL;
+       if (sdp->sd_args.ar_nobarrier)
+               set_bit(SDF_NOBARRIERS, &sdp->sd_flags);
 
        sb->s_magic = GFS2_MAGIC;
        sb->s_op = &gfs2_super_ops;

diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index b1dcfab..5e4b314 100644 (file)
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -73,6 +73,8 @@ enum {
        Opt_statfs_quantum,
        Opt_statfs_percent,
        Opt_quota_quantum,
+       Opt_barrier,
+       Opt_nobarrier,
        Opt_error,
 };
 
@@ -107,6 +109,8 @@ static const match_table_t tokens = {
        {Opt_statfs_quantum, "statfs_quantum=%d"},
        {Opt_statfs_percent, "statfs_percent=%d"},
        {Opt_quota_quantum, "quota_quantum=%d"},
+       {Opt_barrier, "barrier"},
+       {Opt_nobarrier, "nobarrier"},
        {Opt_error, NULL}
 };
 
@@ -253,6 +257,12 @@ int gfs2_mount_args(struct gfs2_args *args, char *options)
                        }
                        args->ar_errors = GFS2_ERRORS_PANIC;
                        break;
+               case Opt_barrier:
+                       args->ar_nobarrier = 0;
+                       break;
+               case Opt_nobarrier:
+                       args->ar_nobarrier = 1;
+                       break;
                case Opt_error:
                default:
                        printk(KERN_WARNING "GFS2: invalid mount option: %s\n", o);
@@ -1143,6 +1153,10 @@ static int gfs2_remount_fs(struct super_block *sb, int *flags, char *data)
                sb->s_flags |= MS_POSIXACL;
        else
                sb->s_flags &= ~MS_POSIXACL;
+       if (sdp->sd_args.ar_nobarrier)
+               set_bit(SDF_NOBARRIERS, &sdp->sd_flags);
+       else
+               clear_bit(SDF_NOBARRIERS, &sdp->sd_flags);
        spin_lock(&gt->gt_spin);
        gt->gt_log_flush_secs = args.ar_commit;
        gt->gt_quota_quantum = args.ar_quota_quantum;