[Cluster-devel] [PATCH 2/2] gfs2-utils: check and fix bad dinode pointers in gfs1 sb

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
| This patch makes gfs2_convert check for bad values of sb_seg_size,
| sb_quota_di and sb_license_di.
| 
| In fsck.gfs2, attempts are made to correct these erroneous values.
| 
| Resolves: rhbz#1053668
| Signed-off-by: Abhi Das <adas@redhat.com>
(snip)
| diff --git a/gfs2/fsck/initialize.c b/gfs2/fsck/initialize.c
| index 0f33aa6..24e5de2 100644
| --- a/gfs2/fsck/initialize.c
| +++ b/gfs2/fsck/initialize.c
| @@ -727,6 +727,13 @@ static int init_system_inodes(struct gfs2_sbd *sdp)
|  	}
|  
|  	if (sdp->gfs1) {
| +		/* In gfs1, the license_di is always 3 blocks after the jindex_di */
| +		if (sbd1->sb_license_di.no_addr != sbd1->sb_jindex_di.no_addr + 3) {
| +			sbd1->sb_license_di.no_addr = sbd1->sb_license_di.no_formal_ino
| +				= sbd1->sb_jindex_di.no_addr + 3;
| +			log_err(_("Reset statfs inode block address to: %llu\n"),
| +				sbd1->sb_license_di.no_addr);
| +		}

This resolves the problem in memory, but doesn't fix it on disk.
We should probably fix it on disk and also use function query() to
get their permission. Same for the quota file.

| +static int reset_journal_seg_size(unsigned int jsize, unsigned int nsegs,
| +					     unsigned int bsize)
| +{
| +	unsigned int seg_size = jsize / (nsegs * bsize);
| +	if (!seg_size)
| +		seg_size = 16; /* The default with 128MB journal and 4K bsize */
| +	if (seg_size != sbd1->sb_seg_size) {
| +		sbd1->sb_seg_size = seg_size;
| +		if (!query(_("Computed correct journal segment size to %u."
| +			     " Reset it? (y/n) "), seg_size)) {
| +			log_crit(_("Error: Cannot proceed without a valid journal"
| +				   " segment size value.\n"));
| +			return -1;
| +		}
| +		log_err(_("Resetting journal segment size to %u\n"), sbd1->sb_seg_size);

Is the superblock being rewritten with the new value anywhere?
If the value is only used for fsck purposes, then no problem. If
there are places in gfs2_convert that may reference it (possibly
through libgfs2) then we should fix it on disk as well.

| +static int correct_journal_seg_size(struct gfs2_sbd *sdp)
| +{
| +	int count;
| +	struct gfs_jindex ji_0, ji_1;
| +	char buf[sizeof(struct gfs_jindex)];
| +	unsigned int jsize = GFS2_DEFAULT_JSIZE * 1024 * 1024;
| +
| +	count = gfs2_readi(sdp->md.jiinode, buf, 0, sizeof(struct gfs_jindex));
| +	if (count != sizeof(struct gfs_jindex))
| +		return -1;

We should probably log an error message here.

| +	return reset_journal_seg_size(jsize, ji_0.ji_nsegment, sbd1->sb_bsize);

ALso, make sure to test with a clean file system and "-n" to make sure it
doesn't try to make changes. I think it's okay, but I always check it
(I've been burned too many times in the past!).

Regards,

Bob Peterson
Red Hat File Systems