gfs2: Get rid of duplicate log head lookup

JIRA: https://issues.redhat.com/browse/RHEL-91331
Upstream Status: https://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2.git

Currently at mount time, the recovery code looks up the current log head
and, if necessary, replays the log and writes a recovery header to
indicate that the log is clean.  It does that for each log that may need
recovery.  We also know that our own log will always be checked as part
of that process.  Then, the mount code looks up the log head of our own
log again.

The double log head lookup can be costly, but more importantly, it is
unnecessary because we can trivially compute the position of the log
head after recovery; all we need to do for that is bump the position and
lh_sequence by one when writing a recovery header.

With that in mind, move the call to gfs2_log_pointers_init() into
gfs2_recover_func() and get rid of the double lookup in
gfs2_make_fs_rw().

Signed-off-by: Andreas Gruenbacher <[email protected]>
(cherry picked from commit 7545d2b8ed49a6aa86d5acedcb7700ba7cc9f8cd)

Author: Andreas Gruenbacher

fs/gfs2/recovery.c

@@ -529,6 +529,9 @@ void gfs2_recover_func(struct work_struct *work)
 			ktime_ms_delta(t_rep, t_tlck));
 	}
 
+	if (jd->jd_jid == sdp->sd_lockstruct.ls_jid)
+		gfs2_log_pointers_init(sdp, &head);
+
 	gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_SUCCESS);
 
 	if (jlocked) {

fs/gfs2/super.c

@@ -134,27 +134,18 @@ int gfs2_make_fs_rw(struct gfs2_sbd *sdp)
 {
 	struct gfs2_inode *ip = GFS2_I(sdp->sd_jdesc->jd_inode);
 	struct gfs2_glock *j_gl = ip->i_gl;
-	struct gfs2_log_header_host head;
 	int error;
 
 	j_gl->gl_ops->go_inval(j_gl, DIO_METADATA);
 	if (gfs2_withdrawn(sdp))
 		return -EIO;
 
-	error = gfs2_find_jhead(sdp->sd_jdesc, &head, false);
-	if (error) {
-		gfs2_consist(sdp);
-		return error;
-	}
-
-	if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
-		gfs2_consist(sdp);
+	if (sdp->sd_log_sequence == 0) {
+		fs_err(sdp, "unknown status of our own journal jid %d",
+		       sdp->sd_lockstruct.ls_jid);
 		return -EIO;
 	}
 
-	/*  Initialize some head of the log stuff  */
-	gfs2_log_pointers_init(sdp, &head);
-
 	error = gfs2_quota_init(sdp);
 	if (!error && gfs2_withdrawn(sdp))
 		error = -EIO;