Re: panic: ffs_snapshot_mount: already on list

[manu%netbsd.org@localhost (Emmanuel Dreyfus)]

Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:

> maybe clear fs->fs_snapinum[snaploc] in that case ?

I am about to commit the patch below, but the problem 
is: I cannot test it, since I cleaned up the obsolete snapshot 
storage backend file from the machine I had the initial
problem with.

Index: sys/ufs/ffs/ffs_snapshot.c
===================================================================
RCS file: /cvsroot/src/sys/ufs/ffs/ffs_snapshot.c,v
retrieving revision 1.149
diff -U4 -r1.149 ffs_snapshot.c
--- sys/ufs/ffs/ffs_snapshot.c  1 Jun 2017 02:45:15 -0000       1.149
+++ sys/ufs/ffs/ffs_snapshot.c  13 Sep 2018 06:03:32 -0000
@@ -1734,8 +1734,9 @@
  */
 void
 ffs_snapshot_mount(struct mount *mp)
 {
+#ifndef FFS_NO_SNAPSHOT
        struct vnode *devvp = VFSTOUFS(mp)->um_devvp;
        struct fs *fs = VFSTOUFS(mp)->um_fs;
        struct lwp *l = curlwp;
        struct vnode *vp;
@@ -1823,14 +1824,16 @@
 
                /*
                 * Link it onto the active snapshot list.
                 */
-               if (is_active_snapshot(si, ip))
-                       panic("ffs_snapshot_mount: %"PRIu64" already on list",
+               if (is_active_snapshot(si, ip)) {
+                       printf("ffs_snapshot_mount: %"PRIu64" already on list",
                            ip->i_number);
-               else
+                       fs->fs_snapinum[snaploc] = 0;
+               } else {
                        TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap);
-               vp->v_vflag |= VV_SYSTEM;
+                       vp->v_vflag |= VV_SYSTEM;
+               }
                VOP_UNLOCK(vp);
        }
        /*
         * No usable snapshots found.
@@ -1847,8 +1850,9 @@
        si->si_snapblklist = xp->i_snapblklist;
        fscow_establish(mp, ffs_copyonwrite, devvp);
        si->si_gen++;
        mutex_exit(&si->si_lock);
+#endif /* FFS_NO_SNAPSHOT */
 }
 
 /*
  * Disassociate snapshot files when unmounting.



-- 
Emmanuel Dreyfus
http://hcpnet.free.fr/pubz
manu%netbsd.org@localhost