diff options
| author | kib <kib@FreeBSD.org> | 2016-05-21 09:49:35 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2016-05-21 09:49:35 +0000 |
| commit | 93315c1cff124e2e1249601a4396946da1356a5e (patch) | |
| tree | e375b8302bb5f35671d5e5fe5387393f2a25b74f /sys/ufs | |
| parent | d8b7958da03f91b1bc1759e897af966fbd3ed3e4 (diff) | |
| download | FreeBSD-src-93315c1cff124e2e1249601a4396946da1356a5e.zip FreeBSD-src-93315c1cff124e2e1249601a4396946da1356a5e.tar.gz | |
Improve handling of rdev->si_mountpt on mount and unmount of FFS
volumes. Treat the field as a semaphore protecting availability of
the device for mounting. Do no access devvp->v_rdev without the vnode
lock owned.
Protect change of the devvp->v_bufobj bo_ops vector with the vnode
lock.
Reviewed by: bde
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Diffstat (limited to 'sys/ufs')
| -rw-r--r-- | sys/ufs/ffs/ffs_vfsops.c | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/sys/ufs/ffs/ffs_vfsops.c b/sys/ufs/ffs/ffs_vfsops.c index 712fc21..4a57ee5 100644 --- a/sys/ufs/ffs/ffs_vfsops.c +++ b/sys/ufs/ffs/ffs_vfsops.c @@ -764,25 +764,31 @@ ffs_mountfs(devvp, mp, td) cred = td ? td->td_ucred : NOCRED; ronly = (mp->mnt_flag & MNT_RDONLY) != 0; + KASSERT(devvp->v_type == VCHR, ("reclaimed devvp")); dev = devvp->v_rdev; - dev_ref(dev); + if (atomic_cmpset_acq_ptr((uintptr_t *)&dev->si_mountpt, 0, + (uintptr_t)mp) == 0) { + VOP_UNLOCK(devvp, 0); + return (EBUSY); + } DROP_GIANT(); g_topology_lock(); error = g_vfs_open(devvp, &cp, "ffs", ronly ? 0 : 1); g_topology_unlock(); PICKUP_GIANT(); + if (error != 0) { + atomic_store_rel_ptr((uintptr_t *)&dev->si_mountpt, 0); + VOP_UNLOCK(devvp, 0); + return (error); + } + dev_ref(dev); + devvp->v_bufobj.bo_ops = &ffs_ops; VOP_UNLOCK(devvp, 0); - if (error) - goto out; - if (devvp->v_rdev->si_iosize_max != 0) - mp->mnt_iosize_max = devvp->v_rdev->si_iosize_max; + if (dev->si_iosize_max != 0) + mp->mnt_iosize_max = dev->si_iosize_max; if (mp->mnt_iosize_max > MAXPHYS) mp->mnt_iosize_max = MAXPHYS; - devvp->v_bufobj.bo_ops = &ffs_ops; - if (devvp->v_type == VCHR) - devvp->v_rdev->si_mountpt = mp; - fs = NULL; sblockloc = 0; /* @@ -1083,8 +1089,6 @@ ffs_mountfs(devvp, mp, td) out: if (bp) brelse(bp); - if (devvp->v_type == VCHR && devvp->v_rdev != NULL) - devvp->v_rdev->si_mountpt = NULL; if (cp != NULL) { DROP_GIANT(); g_topology_lock(); @@ -1102,6 +1106,7 @@ out: free(ump, M_UFSMNT); mp->mnt_data = NULL; } + atomic_store_rel_ptr((uintptr_t *)&dev->si_mountpt, 0); dev_rel(dev); return (error); } @@ -1287,8 +1292,7 @@ ffs_unmount(mp, mntflags) g_vfs_close(ump->um_cp); g_topology_unlock(); PICKUP_GIANT(); - if (ump->um_devvp->v_type == VCHR && ump->um_devvp->v_rdev != NULL) - ump->um_devvp->v_rdev->si_mountpt = NULL; + atomic_store_rel_ptr((uintptr_t *)&ump->um_dev->si_mountpt, 0); vrele(ump->um_devvp); dev_rel(ump->um_dev); mtx_destroy(UFS_MTX(ump)); |
