gfs2: Add new sysfs file for gfs2 status

This patch adds a new file: /sys/fs/gfs2/*/status which will report
the status of the file system. Catting this file dumps the current
status of the file system according to various superblock variables.
For example:

Journal Checked:          1
Journal Live:             1
Journal ID:               0
Spectator:                0
Withdrawn:                0
No barriers:              0
No recovery:              0
Demote:                   0
No Journal ID:            1
Mounted RO:               0
RO Recovery:              0
Skip DLM Unlock:          0
Force AIL Flush:          0
FS Frozen:                0
Withdrawing:              0
Withdraw In Prog:         0
Remote Withdraw:          0
Withdraw Recovery:        0
sd_log_error:             0
sd_log_flush_lock:        0
sd_log_num_revoke:        0
sd_log_in_flight:         0
sd_log_blks_needed:       0
sd_log_blks_free:         32768
sd_log_flush_head:        0
sd_log_flush_tail:        5384
sd_log_blks_reserved:     0
sd_log_revokes_available: 503

Signed-off-by: Bob Peterson <[email protected]>
Signed-off-by: Andreas Gruenbacher <[email protected]>

Author: AstralBob

fs/gfs2/sys.c

@@ -63,6 +63,71 @@ static ssize_t id_show(struct gfs2_sbd *sdp, char *buf)
 			MAJOR(sdp->sd_vfs->s_dev), MINOR(sdp->sd_vfs->s_dev));
 }
 
+static ssize_t status_show(struct gfs2_sbd *sdp, char *buf)
+{
+	unsigned long f = sdp->sd_flags;
+	ssize_t s;
+
+	s = snprintf(buf, PAGE_SIZE,
+		     "Journal Checked:          %d\n"
+		     "Journal Live:             %d\n"
+		     "Journal ID:               %d\n"
+		     "Spectator:                %d\n"
+		     "Withdrawn:                %d\n"
+		     "No barriers:              %d\n"
+		     "No recovery:              %d\n"
+		     "Demote:                   %d\n"
+		     "No Journal ID:            %d\n"
+		     "Mounted RO:               %d\n"
+		     "RO Recovery:              %d\n"
+		     "Skip DLM Unlock:          %d\n"
+		     "Force AIL Flush:          %d\n"
+		     "FS Frozen:                %d\n"
+		     "Withdrawing:              %d\n"
+		     "Withdraw In Prog:         %d\n"
+		     "Remote Withdraw:          %d\n"
+		     "Withdraw Recovery:        %d\n"
+		     "sd_log_error:             %d\n"
+		     "sd_log_flush_lock:        %d\n"
+		     "sd_log_num_revoke:        %u\n"
+		     "sd_log_in_flight:         %d\n"
+		     "sd_log_blks_needed:       %d\n"
+		     "sd_log_blks_free:         %d\n"
+		     "sd_log_flush_head:        %d\n"
+		     "sd_log_flush_tail:        %d\n"
+		     "sd_log_blks_reserved:     %d\n"
+		     "sd_log_revokes_available: %d\n",
+		     test_bit(SDF_JOURNAL_CHECKED, &f),
+		     test_bit(SDF_JOURNAL_LIVE, &f),
+		     (sdp->sd_jdesc ? sdp->sd_jdesc->jd_jid : 0),
+		     (sdp->sd_args.ar_spectator ? 1 : 0),
+		     test_bit(SDF_WITHDRAWN, &f),
+		     test_bit(SDF_NOBARRIERS, &f),
+		     test_bit(SDF_NORECOVERY, &f),
+		     test_bit(SDF_DEMOTE, &f),
+		     test_bit(SDF_NOJOURNALID, &f),
+		     (sb_rdonly(sdp->sd_vfs) ? 1 : 0),
+		     test_bit(SDF_RORECOVERY, &f),
+		     test_bit(SDF_SKIP_DLM_UNLOCK, &f),
+		     test_bit(SDF_FORCE_AIL_FLUSH, &f),
+		     test_bit(SDF_FS_FROZEN, &f),
+		     test_bit(SDF_WITHDRAWING, &f),
+		     test_bit(SDF_WITHDRAW_IN_PROG, &f),
+		     test_bit(SDF_REMOTE_WITHDRAW, &f),
+		     test_bit(SDF_WITHDRAW_RECOVERY, &f),
+		     sdp->sd_log_error,
+		     rwsem_is_locked(&sdp->sd_log_flush_lock),
+		     sdp->sd_log_num_revoke,
+		     atomic_read(&sdp->sd_log_in_flight),
+		     atomic_read(&sdp->sd_log_blks_needed),
+		     atomic_read(&sdp->sd_log_blks_free),
+		     sdp->sd_log_flush_head,
+		     sdp->sd_log_flush_tail,
+		     sdp->sd_log_blks_reserved,
+		     atomic_read(&sdp->sd_log_revokes_available));
+	return s;
+}
+
 static ssize_t fsname_show(struct gfs2_sbd *sdp, char *buf)
 {
 	return snprintf(buf, PAGE_SIZE, "%s\n", sdp->sd_fsname);
@@ -283,6 +348,7 @@ GFS2_ATTR(quota_sync,          0200, NULL,          quota_sync_store);
 GFS2_ATTR(quota_refresh_user,  0200, NULL,          quota_refresh_user_store);
 GFS2_ATTR(quota_refresh_group, 0200, NULL,          quota_refresh_group_store);
 GFS2_ATTR(demote_rq,           0200, NULL,	    demote_rq_store);
+GFS2_ATTR(status,              0400, status_show,   NULL);
 
 static struct attribute *gfs2_attrs[] = {
 	&gfs2_attr_id.attr,
@@ -295,6 +361,7 @@ static struct attribute *gfs2_attrs[] = {
 	&gfs2_attr_quota_refresh_user.attr,
 	&gfs2_attr_quota_refresh_group.attr,
 	&gfs2_attr_demote_rq.attr,
+	&gfs2_attr_status.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(gfs2);