[Cluster-devel] [GFS2 Patch] GFS2: Don't flag consistency error if first mounter is a spectator

[Steven Whitehouse <swhiteho@redhat.com>]

Hi,

Now in the -nmw git tree. Thanks,

Steve.

On Wed, 2013-09-04 at 12:08 -0400, Bob Peterson wrote:
> Hi,
> 
> This patch checks for the first mounter being a specator. If so, it
> makes sure all the journals are clean. If there's a dirty journal,
> the mount fails.
> 
> Testing results:
> 
> # insmod gfs2.ko
> # mount -tgfs2 -o spectator /dev/sasdrives/scratch /mnt/gfs2
> mount: permission denied
> # dmesg | tail -2
> [ 3390.655996] GFS2: fsid=MUSKETEER:home: Now mounting FS...
> [ 3390.841336] GFS2: fsid=MUSKETEER:home.s: jid=0: Journal is dirty, so the first mounter must not be a spectator.
> # mount -tgfs2 /dev/sasdrives/scratch /mnt/gfs2
> # umount /mnt/gfs2
> # mount -tgfs2 -o spectator /dev/sasdrives/scratch /mnt/gfs2
> # ls /mnt/gfs2|wc -l
> 352
> # umount /mnt/gfs2
> 
> Regards,
> 
> Bob Peterson
> Red Hat File Systems
> 
> Signed-off-by: Bob Peterson <rpeterso@redhat.com> 
> ---
> diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
> index 0262c19..19ff5e8 100644
> --- a/fs/gfs2/ops_fstype.c
> +++ b/fs/gfs2/ops_fstype.c
> @@ -646,6 +646,48 @@ static int gfs2_jindex_hold(struct gfs2_sbd *sdp, struct gfs2_holder *ji_gh)
>  	return error;
>  }
>  
> +/**
> + * check_journal_clean - Make sure a journal is clean for a spectator mount
> + * @sdp: The GFS2 superblock
> + * @jd: The journal descriptor
> + *
> + * Returns: 0 if the journal is clean or locked, else an error
> + */
> +static int check_journal_clean(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd)
> +{
> +	int error;
> +	struct gfs2_holder j_gh;
> +	struct gfs2_log_header_host head;
> +	struct gfs2_inode *ip;
> +
> +	ip = GFS2_I(jd->jd_inode);
> +	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_NOEXP |
> +				   GL_EXACT | GL_NOCACHE, &j_gh);
> +	if (error) {
> +		fs_err(sdp, "Error locking journal for spectator mount.\n");
> +		return -EPERM;
> +	}
> +	error = gfs2_jdesc_check(jd);
> +	if (error) {
> +		fs_err(sdp, "Error checking journal for spectator mount.\n");
> +		goto out_unlock;
> +	}
> +	error = gfs2_find_jhead(jd, &head);
> +	if (error) {
> +		fs_err(sdp, "Error parsing journal for spectator mount.\n");
> +		goto out_unlock;
> +	}
> +	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
> +		error = -EPERM;
> +		fs_err(sdp, "jid=%u: Journal is dirty, so the first mounter "
> +		       "must not be a spectator.\n", jd->jd_jid);
> +	}
> +
> +out_unlock:
> +	gfs2_glock_dq_uninit(&j_gh);
> +	return error;
> +}
> +
>  static int init_journal(struct gfs2_sbd *sdp, int undo)
>  {
>  	struct inode *master = sdp->sd_master_dir->d_inode;
> @@ -732,8 +774,15 @@ static int init_journal(struct gfs2_sbd *sdp, int undo)
>  	if (sdp->sd_lockstruct.ls_first) {
>  		unsigned int x;
>  		for (x = 0; x < sdp->sd_journals; x++) {
> -			error = gfs2_recover_journal(gfs2_jdesc_find(sdp, x),
> -						     true);
> +			struct gfs2_jdesc *jd = gfs2_jdesc_find(sdp, x);
> +
> +			if (sdp->sd_args.ar_spectator) {
> +				error = check_journal_clean(sdp, jd);
> +				if (error)
> +					goto fail_jinode_gh;
> +				continue;
> +			}
> +			error = gfs2_recover_journal(jd, true);
>  			if (error) {
>  				fs_err(sdp, "error recovering journal %u: %d\n",
>  				       x, error);
>