[src/trunk]: src/sys/ufs/ffs Revert rev. 1.101. Dead snapshots would hang ar...

[hannken <hannken%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/e54be36e2588
branches:  trunk
changeset: 762248:e54be36e2588
user:      hannken <hannken%NetBSD.org@localhost>
date:      Fri Feb 18 08:39:13 2011 +0000

description:
Revert rev. 1.101.  Dead snapshots would hang around until unmount.

Adresses PR #44568 (WAPBL doens't play nice with snapshots).

diffstat:

 sys/ufs/ffs/ffs_snapshot.c |  40 ++++++++++++++++++++++------------------
 1 files changed, 22 insertions(+), 18 deletions(-)

diffs (97 lines):

diff -r ecdc125ea6a5 -r e54be36e2588 sys/ufs/ffs/ffs_snapshot.c
--- a/sys/ufs/ffs/ffs_snapshot.c        Fri Feb 18 07:00:05 2011 +0000
+++ b/sys/ufs/ffs/ffs_snapshot.c        Fri Feb 18 08:39:13 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ffs_snapshot.c,v 1.103 2011/02/16 19:43:50 hannken Exp $       */
+/*     $NetBSD: ffs_snapshot.c,v 1.104 2011/02/18 08:39:13 hannken Exp $       */
 
 /*
  * Copyright 2000 Marshall Kirk McKusick. All Rights Reserved.
@@ -38,7 +38,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ffs_snapshot.c,v 1.103 2011/02/16 19:43:50 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ffs_snapshot.c,v 1.104 2011/02/18 08:39:13 hannken Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_ffs.h"
@@ -280,7 +280,6 @@
        fs->fs_snapinum[snaploc] = ip->i_number;
 
        mutex_enter(&si->si_lock);
-       vref(vp);
        if (is_active_snapshot(si, ip))
                panic("ffs_snapshot: %"PRIu64" already on list", ip->i_number);
        TAILQ_INSERT_TAIL(&si->si_snapshots, ip, i_nextsnap);
@@ -394,7 +393,8 @@
                        (void) ffs_truncate(vp, (off_t)0, 0, NOCRED);
                        UFS_WAPBL_END(mp);
                }
-       }
+       } else
+               vref(vp);
        return (error);
 }
 
@@ -1313,8 +1313,10 @@
                if (xp == ip)
                        break;
        mutex_exit(&si->si_lock);
+       if (xp != NULL)
+               vrele(ITOV(ip));
 #ifdef DEBUG
-       if (snapdebug && xp == NULL)
+       else if (snapdebug)
                printf("ffs_snapgone: lost snapshot vnode %llu\n",
                    (unsigned long long)ip->i_number);
 #endif
@@ -1382,7 +1384,6 @@
                        free(ip->i_snapblklist, M_UFSMNT);
                        ip->i_snapblklist = NULL;
                }
-               vrele(vp);
        } else
                mutex_exit(&si->si_lock);
        /*
@@ -1763,25 +1764,28 @@
 ffs_snapshot_unmount(struct mount *mp)
 {
        struct vnode *devvp = VFSTOUFS(mp)->um_devvp;
-       struct inode *ip;
+       struct inode *xp;
+       struct vnode *vp = NULL;
        struct snap_info *si;
-       bool list_empty = true;
 
        si = VFSTOUFS(mp)->um_snapinfo;
        mutex_enter(&si->si_lock);
-       while ((ip = TAILQ_FIRST(&si->si_snapshots)) != 0) {
-               list_empty = false;
-               TAILQ_REMOVE(&si->si_snapshots, ip, i_nextsnap);
-               if (ip->i_snapblklist == si->si_snapblklist)
+       while ((xp = TAILQ_FIRST(&si->si_snapshots)) != 0) {
+               vp = ITOV(xp);
+               TAILQ_REMOVE(&si->si_snapshots, xp, i_nextsnap);
+               if (xp->i_snapblklist == si->si_snapblklist)
                        si->si_snapblklist = NULL;
-               free(ip->i_snapblklist, M_UFSMNT);
-               si->si_gen++;
-               mutex_exit(&si->si_lock);
-               vrele(ITOV(ip));
-               mutex_enter(&si->si_lock);
+               free(xp->i_snapblklist, M_UFSMNT);
+               if (xp->i_nlink > 0) {
+                       si->si_gen++;
+                       mutex_exit(&si->si_lock);
+                       vrele(vp);
+                       mutex_enter(&si->si_lock);
+               }
        }
+       si->si_gen++;
        mutex_exit(&si->si_lock);
-       if (! list_empty)
+       if (vp)
                fscow_disestablish(mp, ffs_copyonwrite, devvp);
 }