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Revert previous commit. Locking the snapshot vnode while the file system 

is suspended extends the suspension until the vnode gets unlocked by
the caller of ffs_snapshot().

Resuming the file system before expunging all snapshots and syncing the
snapshot creates races and deadlocks with journaling file systems at least.
This commit is contained in:
hannken 2011-05-08 18:37:15 +00:00
parent 821775e983
commit f7e12f18b3
1 changed files with 13 additions and 27 deletions
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40
sys/ufs/ffs/ffs_snapshot.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: ffs_snapshot.c,v 1.114 2011/04/29 09:45:15 hannken Exp $ */
/* $NetBSD: ffs_snapshot.c,v 1.115 2011/05/08 18:37:15 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 1.114 2011/04/29 09:45:15 hannken Exp $");
__KERNEL_RCSID(0, "$NetBSD: ffs_snapshot.c,v 1.115 2011/05/08 18:37:15 hannken Exp $");
#if defined(_KERNEL_OPT)
#include "opt_ffs.h"
@ -177,7 +177,7 @@ ffs_snapshot(struct mount *mp, struct vnode *vp, struct timespec *ctime)
return EOPNOTSUPP;
}
#else /* defined(FFS_NO_SNAPSHOT) */
bool suspended = false, snapshot_locked = false;
bool suspended = false;
int error, redo = 0, snaploc;
void *sbbuf = NULL;
daddr_t *snaplist = NULL, snaplistsize = 0;
@ -309,24 +309,6 @@ ffs_snapshot(struct mount *mp, struct vnode *vp, struct timespec *ctime)
DIP_ASSIGN(ip, mtime, ts.tv_sec);
DIP_ASSIGN(ip, mtimensec, ts.tv_nsec);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
/*
* Lock the snapshot and resume file system.
*/
mutex_enter(&si->si_snaplock);
mutex_enter(&si->si_lock);
si->si_owner = curlwp;
mutex_exit(&si->si_lock);
snapshot_locked = true;
KASSERT(suspended);
vfs_resume(vp->v_mount);
suspended = false;
#ifdef DEBUG
getmicrotime(&endtime);
timersub(&endtime, &starttime, &endtime);
printf("%s: suspended %lld.%03d sec, redo %d of %d\n",
mp->mnt_stat.f_mntonname, (long long)endtime.tv_sec,
endtime.tv_usec / 1000, redo, fs->fs_ncg);
#endif
/*
* Copy allocation information from all snapshots and then
* expunge them from our view.
@ -399,13 +381,17 @@ out:
si->si_gen++;
mutex_exit(&si->si_lock);
if (suspended)
if (suspended) {
VOP_UNLOCK(vp);
vfs_resume(vp->v_mount);
if (snapshot_locked) {
mutex_enter(&si->si_lock);
si->si_owner = NULL;
mutex_exit(&si->si_lock);
mutex_exit(&si->si_snaplock);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
#ifdef DEBUG
getmicrotime(&endtime);
timersub(&endtime, &starttime, &endtime);
printf("%s: suspended %lld.%03d sec, redo %d of %d\n",
mp->mnt_stat.f_mntonname, (long long)endtime.tv_sec,
endtime.tv_usec / 1000, redo, fs->fs_ncg);
#endif
}
if (error) {
if (!UFS_WAPBL_BEGIN(mp)) {