/*
* Undo loopback mount
*/
static int
lo_unmount(struct vfs *vfsp, int flag, struct cred *cr)
{
struct loinfo *li;
if (secpolicy_fs_unmount(cr, vfsp) != 0)
return (EPERM);
/*
* Forced unmount is not supported by this file system
* and thus, ENOTSUP, is being returned.
*/
if (flag & MS_FORCE)
return (ENOTSUP);
li = vtoli(vfsp);
#ifdef LODEBUG
lo_dprint(4, "lo_unmount(%p) li %p\n", vfsp, li);
#endif
if (li->li_refct != 1 || li->li_rootvp->v_count != 1) {
#ifdef LODEBUG
lo_dprint(4, "refct %d v_ct %d\n", li->li_refct,
li->li_rootvp->v_count);
#endif
return (EBUSY);
}
VN_RELE(li->li_rootvp);
return (0);
}
/*
* Find root of lofs mount.
*/
static int
lo_root(struct vfs *vfsp, struct vnode **vpp)
{
*vpp = vtoli(vfsp)->li_rootvp;
#ifdef LODEBUG
lo_dprint(4, "lo_root(0x%p) = %p\n", vfsp, *vpp);
#endif
/*
* If the root of the filesystem is a special file, return the specvp
* version of the vnode. We don't save the specvp vnode in our
* hashtable since that's exclusively for lnodes.
*/
if (IS_DEVVP(*vpp)) {
struct vnode *svp;
svp = specvp(*vpp, (*vpp)->v_rdev, (*vpp)->v_type, kcred);
if (svp == NULL)
return (ENOSYS);
*vpp = svp;
} else {
VN_HOLD(*vpp);
}
return (0);
}
/* ARGSUSED */
static int
lo_sync(struct vfs *vfsp,
short flag,
struct cred *cr)
{
#ifdef LODEBUG
lo_dprint(4, "lo_sync: %p\n", vfsp);
#endif
return (0);
}
/*
* Obtain the vnode from the underlying filesystem.
*/
static int
lo_vget(struct vfs *vfsp, struct vnode **vpp, struct fid *fidp)
{
vnode_t *realrootvp;
#ifdef LODEBUG
lo_dprint(4, "lo_vget: %p\n", vfsp);
#endif
(void) lo_realvfs(vfsp, &realrootvp);
if (realrootvp != NULL)
return (VFS_VGET(realrootvp->v_vfsp, vpp, fidp));
else
return (EIO);
}
/*
* Get file system statistics.
*/
static int
lo_statvfs(register struct vfs *vfsp, struct statvfs64 *sbp)
{
vnode_t *realrootvp;
#ifdef LODEBUG
lo_dprint(4, "lostatvfs %p\n", vfsp);
#endif
/*
* Using realrootvp->v_vfsp (instead of the realvfsp that was
* cached) is necessary to make lofs work woth forced UFS unmounts.
* In the case of a forced unmount, UFS stores a set of dummy vfsops
* in all the (i)vnodes in the filesystem. The dummy ops simply
* returns back EIO.
*/
(void) lo_realvfs(vfsp, &realrootvp);
if (realrootvp != NULL)
return (VFS_STATVFS(realrootvp->v_vfsp, sbp));
else
return (EIO);
}
/*
* Put a lnode in the table
*/
static void
lsave(lnode_t *lp, struct loinfo *li)
{
ASSERT(lp->lo_vp);
ASSERT(MUTEX_HELD(TABLE_LOCK(lp->lo_vp, li)));
#ifdef LODEBUG
lo_dprint(4, "lsave lp %p hash %d\n",
lp, ltablehash(lp->lo_vp, li));
#endif
TABLE_COUNT(lp->lo_vp, li)++;
lp->lo_next = TABLE_BUCKET(lp->lo_vp, li);
TABLE_BUCKET(lp->lo_vp, li) = lp;
if (li->li_refct > (li->li_htsize << lo_resize_threshold)) {
TABLE_LOCK_EXIT(lp->lo_vp, li);
lgrow(li, li->li_htsize << lo_resize_factor);
TABLE_LOCK_ENTER(lp->lo_vp, li);
}
}
/*ARGSUSED*/
static int
lo_mount(struct vfs *vfsp,
struct vnode *vp,
struct mounta *uap,
struct cred *cr)
{
int error;
struct vnode *srootvp = NULL; /* the server's root */
struct vnode *realrootvp;
struct loinfo *li;
int nodev;
nodev = vfs_optionisset(vfsp, MNTOPT_NODEVICES, NULL);
if ((error = secpolicy_fs_mount(cr, vp, vfsp)) != 0)
return (EPERM);
/*
* Loopback devices which get "nodevices" added can be done without
* "nodevices" set because we cannot import devices into a zone
* with loopback. Note that we have all zone privileges when
* this happens; if not, we'd have gotten "nosuid".
*/
if (!nodev && vfs_optionisset(vfsp, MNTOPT_NODEVICES, NULL))
vfs_setmntopt(vfsp, MNTOPT_DEVICES, NULL, VFS_NODISPLAY);
mutex_enter(&vp->v_lock);
if (!(uap->flags & MS_OVERLAY) &&
(vp->v_count != 1 || (vp->v_flag & VROOT))) {
mutex_exit(&vp->v_lock);
return (EBUSY);
}
mutex_exit(&vp->v_lock);
/*
* Find real root, and make vfs point to real vfs
*/
if (error = lookupname(uap->spec, (uap->flags & MS_SYSSPACE) ?
UIO_SYSSPACE : UIO_USERSPACE, FOLLOW, NULLVPP, &realrootvp))
return (error);
/*
* Enforce MAC policy if needed.
*
* Loopback mounts must not allow writing up. The dominance test
* is intended to prevent a global zone caller from accidentally
* creating write-up conditions between two labeled zones.
* Local zones can't violate MAC on their own without help from
* the global zone because they can't name a pathname that
* they don't already have.
*
* The special case check for the NET_MAC_AWARE process flag is
* to support the case of the automounter in the global zone. We
* permit automounting of local zone directories such as home
* directories, into the global zone as required by setlabel,
* zonecopy, and saving of desktop sessions. Such mounts are
* trusted not to expose the contents of one zone's directories
* to another by leaking them through the global zone.
*/
if (is_system_labeled() && crgetzoneid(cr) == GLOBAL_ZONEID) {
char specname[MAXPATHLEN];
zone_t *from_zptr;
zone_t *to_zptr;
if (vnodetopath(NULL, realrootvp, specname,
sizeof (specname), CRED()) != 0) {
VN_RELE(realrootvp);
return (EACCES);
}
from_zptr = zone_find_by_path(specname);
to_zptr = zone_find_by_path(refstr_value(vfsp->vfs_mntpt));
/*
* Special case for zone devfs: the zone for /dev will
* incorrectly appear as the global zone since it's not
* under the zone rootpath. So for zone devfs check allow
* read-write mounts.
*
* Second special case for scratch zones used for Live Upgrade:
* this is used to mount the zone's root from /root to /a in
* the scratch zone. As with the other special case, this
* appears to be outside of the zone because it's not under
* the zone rootpath, which is $ZONEPATH/lu in the scratch
* zone case.
*/
if (from_zptr != to_zptr &&
!(to_zptr->zone_flags & ZF_IS_SCRATCH)) {
/*
* We know at this point that the labels aren't equal
* because the zone pointers aren't equal, and zones
* can't share a label.
*
* If the source is the global zone then making
* it available to a local zone must be done in
* read-only mode as the label will become admin_low.
*
* If it is a mount between local zones then if
* the current process is in the global zone and has
* the NET_MAC_AWARE flag, then regular read-write
* access is allowed. If it's in some other zone, but
* the label on the mount point dominates the original
* source, then allow the mount as read-only
* ("read-down").
*/
if (from_zptr->zone_id == GLOBAL_ZONEID) {
/* make the mount read-only */
vfs_setmntopt(vfsp, MNTOPT_RO, NULL, 0);
} else { /* cross-zone mount */
if (to_zptr->zone_id == GLOBAL_ZONEID &&
/* LINTED: no consequent */
getpflags(NET_MAC_AWARE, cr) != 0) {
/* Allow the mount as read-write */
} else if (bldominates(
label2bslabel(to_zptr->zone_slabel),
label2bslabel(from_zptr->zone_slabel))) {
/* make the mount read-only */
vfs_setmntopt(vfsp, MNTOPT_RO, NULL, 0);
} else {
VN_RELE(realrootvp);
zone_rele(to_zptr);
zone_rele(from_zptr);
return (EACCES);
}
}
}
zone_rele(to_zptr);
zone_rele(from_zptr);
}
/*
* realrootvp may be an AUTOFS node, in which case we
* perform a VOP_ACCESS() to trigger the mount of the
* intended filesystem, so we loopback mount the intended
* filesystem instead of the AUTOFS filesystem.
*/
(void) VOP_ACCESS(realrootvp, 0, 0, cr, NULL);
/*
* We're interested in the top most filesystem.
* This is specially important when uap->spec is a trigger
* AUTOFS node, since we're really interested in mounting the
* filesystem AUTOFS mounted as result of the VOP_ACCESS()
* call not the AUTOFS node itself.
*/
if (vn_mountedvfs(realrootvp) != NULL) {
if (error = traverse(&realrootvp)) {
VN_RELE(realrootvp);
return (error);
}
}
/*
* Allocate a vfs info struct and attach it
*/
li = kmem_zalloc(sizeof (struct loinfo), KM_SLEEP);
li->li_realvfs = realrootvp->v_vfsp;
li->li_mountvfs = vfsp;
/*
* Set mount flags to be inherited by loopback vfs's
*/
if (vfs_optionisset(vfsp, MNTOPT_RO, NULL)) {
li->li_mflag |= VFS_RDONLY;
}
if (vfs_optionisset(vfsp, MNTOPT_NOSUID, NULL)) {
li->li_mflag |= (VFS_NOSETUID|VFS_NODEVICES);
}
if (vfs_optionisset(vfsp, MNTOPT_NODEVICES, NULL)) {
li->li_mflag |= VFS_NODEVICES;
}
if (vfs_optionisset(vfsp, MNTOPT_NOSETUID, NULL)) {
li->li_mflag |= VFS_NOSETUID;
}
/*
* Permissive flags are added to the "deny" bitmap.
*/
if (vfs_optionisset(vfsp, MNTOPT_NOXATTR, NULL)) {
li->li_dflag |= VFS_XATTR;
}
if (vfs_optionisset(vfsp, MNTOPT_NONBMAND, NULL)) {
li->li_dflag |= VFS_NBMAND;
}
/*
* Propagate inheritable mount flags from the real vfs.
*/
if ((li->li_realvfs->vfs_flag & VFS_RDONLY) &&
!vfs_optionisset(vfsp, MNTOPT_RO, NULL))
vfs_setmntopt(vfsp, MNTOPT_RO, NULL,
VFS_NODISPLAY);
if ((li->li_realvfs->vfs_flag & VFS_NOSETUID) &&
!vfs_optionisset(vfsp, MNTOPT_NOSETUID, NULL))
vfs_setmntopt(vfsp, MNTOPT_NOSETUID, NULL,
VFS_NODISPLAY);
if ((li->li_realvfs->vfs_flag & VFS_NODEVICES) &&
!vfs_optionisset(vfsp, MNTOPT_NODEVICES, NULL))
vfs_setmntopt(vfsp, MNTOPT_NODEVICES, NULL,
VFS_NODISPLAY);
/*
* Permissive flags such as VFS_XATTR, as opposed to restrictive flags
* such as VFS_RDONLY, are handled differently. An explicit
* MNTOPT_NOXATTR should override the underlying filesystem's VFS_XATTR.
*/
if ((li->li_realvfs->vfs_flag & VFS_XATTR) &&
!vfs_optionisset(vfsp, MNTOPT_NOXATTR, NULL) &&
!vfs_optionisset(vfsp, MNTOPT_XATTR, NULL))
vfs_setmntopt(vfsp, MNTOPT_XATTR, NULL,
VFS_NODISPLAY);
if ((li->li_realvfs->vfs_flag & VFS_NBMAND) &&
!vfs_optionisset(vfsp, MNTOPT_NBMAND, NULL) &&
!vfs_optionisset(vfsp, MNTOPT_NONBMAND, NULL))
vfs_setmntopt(vfsp, MNTOPT_NBMAND, NULL,
VFS_NODISPLAY);
li->li_refct = 0;
vfsp->vfs_data = (caddr_t)li;
vfsp->vfs_bcount = 0;
vfsp->vfs_fstype = lofsfstype;
vfsp->vfs_bsize = li->li_realvfs->vfs_bsize;
vfsp->vfs_dev = li->li_realvfs->vfs_dev;
vfsp->vfs_fsid.val[0] = li->li_realvfs->vfs_fsid.val[0];
vfsp->vfs_fsid.val[1] = li->li_realvfs->vfs_fsid.val[1];
if (vfs_optionisset(vfsp, MNTOPT_LOFS_NOSUB, NULL)) {
li->li_flag |= LO_NOSUB;
}
/*
* Propagate any VFS features
*/
vfs_propagate_features(li->li_realvfs, vfsp);
/*
* Setup the hashtable. If the root of this mount isn't a directory,
* there's no point in allocating a large hashtable. A table with one
* bucket is sufficient.
*/
if (realrootvp->v_type != VDIR)
lsetup(li, 1);
else
lsetup(li, 0);
/*
* Make the root vnode
*/
srootvp = makelonode(realrootvp, li, 0);
srootvp->v_flag |= VROOT;
li->li_rootvp = srootvp;
#ifdef LODEBUG
lo_dprint(4, "lo_mount: vfs %p realvfs %p root %p realroot %p li %p\n",
vfsp, li->li_realvfs, srootvp, realrootvp, li);
#endif
return (0);
}
/*
* Remove a lnode from the table
*/
void
freelonode(lnode_t *lp)
{
lnode_t *lt;
lnode_t *ltprev = NULL;
struct lfsnode *lfs, *nextlfs;
struct vfs *vfsp;
struct vnode *vp = ltov(lp);
struct vnode *realvp = realvp(vp);
struct loinfo *li = vtoli(vp->v_vfsp);
#ifdef LODEBUG
lo_dprint(4, "freelonode lp %p hash %d\n",
lp, ltablehash(lp->lo_vp, li));
#endif
TABLE_LOCK_ENTER(lp->lo_vp, li);
mutex_enter(&vp->v_lock);
if (vp->v_count > 1) {
vp->v_count--; /* release our hold from vn_rele */
mutex_exit(&vp->v_lock);
TABLE_LOCK_EXIT(lp->lo_vp, li);
return;
}
mutex_exit(&vp->v_lock);
for (lt = TABLE_BUCKET(lp->lo_vp, li); lt != NULL;
ltprev = lt, lt = lt->lo_next) {
if (lt == lp) {
#ifdef LODEBUG
lo_dprint(4, "freeing %p, vfsp %p\n",
vp, vp->v_vfsp);
#endif
atomic_dec_32(&li->li_refct);
vfsp = vp->v_vfsp;
vn_invalid(vp);
if (vfsp != li->li_mountvfs) {
mutex_enter(&li->li_lfslock);
/*
* Check for unused lfs
*/
lfs = li->li_lfs;
while (lfs != NULL) {
nextlfs = lfs->lfs_next;
if (vfsp == &lfs->lfs_vfs) {
lfs_rele(lfs, li);
break;
}
if (lfs->lfs_vfs.vfs_count == 1) {
/*
* Lfs is idle
*/
freelfsnode(lfs, li);
}
lfs = nextlfs;
}
mutex_exit(&li->li_lfslock);
}
if (ltprev == NULL) {
TABLE_BUCKET(lt->lo_vp, li) = lt->lo_next;
} else {
ltprev->lo_next = lt->lo_next;
}
TABLE_COUNT(lt->lo_vp, li)--;
TABLE_LOCK_EXIT(lt->lo_vp, li);
kmem_cache_free(lnode_cache, lt);
vn_free(vp);
VN_RELE(realvp);
return;
}
}
panic("freelonode");
/*NOTREACHED*/
}
