Author: davide
Date: Sun Apr 13 01:15:37 2014
New Revision: 264392
URL: http://svnweb.freebsd.org/changeset/base/264392
Log:
Fix a panic in zfs_rename().
this is due to a wrong dereference of a vnode when it's not locked and
can be (potentially) recycled. 'sdvp' cannot be locked on zfs_rename()
entry point because the VFS can't be sure that this scenario is
LOR-free (it might violate the parent->child lock acquisition rule).
Dereference 'tdvp' instead, which is already locked on entry, and access
'sdvp' fields only when it's safe, i.e. under ZFS_ENTER scope.
While at it, remove the usage of VOP_REALVP, as long as this is a NOP
on FreeBSD.
Discussed with: avg
Reviewed by: pjd
Modified:
head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c Sun Apr
13 01:14:25 2014 (r264391)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c Sun Apr
13 01:15:37 2014 (r264392)
@@ -3723,9 +3723,8 @@ static int
zfs_rename(vnode_t *sdvp, char *snm, vnode_t *tdvp, char *tnm, cred_t *cr,
caller_context_t *ct, int flags)
{
- znode_t *tdzp, *szp, *tzp;
- znode_t *sdzp = VTOZ(sdvp);
- zfsvfs_t *zfsvfs = sdzp->z_zfsvfs;
+ znode_t *tdzp, *sdzp, *szp, *tzp;
+ zfsvfs_t *zfsvfs;
zilog_t *zilog;
vnode_t *realvp;
zfs_dirlock_t *sdl, *tdl;
@@ -3736,24 +3735,27 @@ zfs_rename(vnode_t *sdvp, char *snm, vno
int zflg = 0;
boolean_t waited = B_FALSE;
+ tdzp = VTOZ(tdvp);
+ ZFS_VERIFY_ZP(tdzp);
+ zfsvfs = tdzp->z_zfsvfs;
ZFS_ENTER(zfsvfs);
- ZFS_VERIFY_ZP(sdzp);
zilog = zfsvfs->z_log;
+ sdzp = VTOZ(sdvp);
/*
- * Make sure we have the real vp for the target directory.
+ * In case sdzp is not valid, let's be sure to exit from the right
+ * zfsvfs_t.
*/
- if (VOP_REALVP(tdvp, &realvp, ct) == 0)
- tdvp = realvp;
-
- tdzp = VTOZ(tdvp);
- ZFS_VERIFY_ZP(tdzp);
+ if (sdzp->z_sa_hdl == NULL) {
+ ZFS_EXIT(zfsvfs);
+ return (SET_ERROR(EIO));
+ }
/*
* We check z_zfsvfs rather than v_vfsp here, because snapshots and the
* ctldir appear to have the same v_vfsp.
*/
- if (tdzp->z_zfsvfs != zfsvfs || zfsctl_is_node(tdvp)) {
+ if (sdzp->z_zfsvfs != zfsvfs || zfsctl_is_node(tdvp)) {
ZFS_EXIT(zfsvfs);
return (SET_ERROR(EXDEV));
}
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