Author: jhb
Date: Fri Jul 16 19:20:20 2010
New Revision: 210171
URL: http://svn.freebsd.org/changeset/base/210171
Log:
When the MNTK_EXTENDED_SHARED mount option was added, some filesystems were
changed to defer the setting of VN_LOCK_ASHARE() (which clears LK_NOSHARE
in the vnode lock's flags) until after they had determined if the vnode was
a FIFO. This occurs after the vnode has been inserted a VFS hash or some
similar table, so it is possible for another thread to find this vnode via
vget() on an i-node number and block on the vnode lock. If the lockmgr
interlock (vnode interlock for vnode locks) is not held when clearing the
LK_NOSHARE flag, then the lk_flags field can be clobbered. As a result
the thread blocked on the vnode lock may never get woken up. Fix this by
holding the vnode interlock while modifying the lock flags in this case.
MFC after: 3 days
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
head/sys/fs/cd9660/cd9660_vfsops.c
head/sys/fs/udf/udf_vfsops.c
head/sys/ufs/ffs/ffs_vfsops.c
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c Fri Jul
16 18:57:45 2010 (r210170)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c Fri Jul
16 19:20:20 2010 (r210171)
@@ -566,8 +566,11 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_bu
}
break;
}
- if (vp->v_type != VFIFO)
+ if (vp->v_type != VFIFO) {
+ VI_LOCK(vp);
VN_LOCK_ASHARE(vp);
+ VI_UNLOCK(vp);
+ }
mutex_enter(&zfsvfs->z_znodes_lock);
list_insert_tail(&zfsvfs->z_all_znodes, zp);
Modified: head/sys/fs/cd9660/cd9660_vfsops.c
==============================================================================
--- head/sys/fs/cd9660/cd9660_vfsops.c Fri Jul 16 18:57:45 2010
(r210170)
+++ head/sys/fs/cd9660/cd9660_vfsops.c Fri Jul 16 19:20:20 2010
(r210171)
@@ -814,7 +814,9 @@ cd9660_vget_internal(mp, ino, flags, vpp
vp->v_op = &cd9660_fifoops;
break;
default:
+ VI_LOCK(vp);
VN_LOCK_ASHARE(vp);
+ VI_UNLOCK(vp);
break;
}
Modified: head/sys/fs/udf/udf_vfsops.c
==============================================================================
--- head/sys/fs/udf/udf_vfsops.c Fri Jul 16 18:57:45 2010
(r210170)
+++ head/sys/fs/udf/udf_vfsops.c Fri Jul 16 19:20:20 2010
(r210171)
@@ -710,8 +710,11 @@ udf_vget(struct mount *mp, ino_t ino, in
break;
}
- if (vp->v_type != VFIFO)
+ if (vp->v_type != VFIFO) {
+ VI_LOCK(vp);
VN_LOCK_ASHARE(vp);
+ VI_UNLOCK(vp);
+ }
if (ino == udf_getid(&udfmp->root_icb))
vp->v_vflag |= VV_ROOT;
Modified: head/sys/ufs/ffs/ffs_vfsops.c
==============================================================================
--- head/sys/ufs/ffs/ffs_vfsops.c Fri Jul 16 18:57:45 2010
(r210170)
+++ head/sys/ufs/ffs/ffs_vfsops.c Fri Jul 16 19:20:20 2010
(r210171)
@@ -1577,7 +1577,9 @@ ffs_vgetf(mp, ino, flags, vpp, ffs_flags
*/
if (vp->v_type != VFIFO) {
/* FFS supports shared locking for all files except fifos. */
+ VI_LOCK(vp);
VN_LOCK_ASHARE(vp);
+ VI_UNLOCK(vp);
}
/*
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