2 * Copyright (c) 1994, 1995 The Regents of the University of California.
3 * Copyright (c) 1994, 1995 Jan-Simon Pendry.
6 * This code is derived from software donated to Berkeley by
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95
38 * $FreeBSD: src/sys/miscfs/union/union_vfsops.c,v 1.39.2.2 2001/10/25 19:18:53 dillon Exp $
39 * $DragonFly: src/sys/vfs/union/union_vfsops.c,v 1.29 2006/12/23 00:41:30 swildner Exp $
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
50 #include <sys/vnode.h>
51 #include <sys/mount.h>
52 #include <sys/nlookup.h>
53 #include <sys/namei.h>
54 #include <sys/malloc.h>
55 #include <sys/filedesc.h>
57 #include <vm/vm_zone.h>
59 extern struct vop_ops union_vnode_vops
;
61 static MALLOC_DEFINE(M_UNIONFSMNT
, "UNION mount", "UNION mount structure");
63 extern int union_init (struct vfsconf
*);
64 static int union_mount (struct mount
*mp
, char *path
, caddr_t data
,
66 static int union_root (struct mount
*mp
, struct vnode
**vpp
);
67 static int union_statfs (struct mount
*mp
, struct statfs
*sbp
,
69 static int union_unmount (struct mount
*mp
, int mntflags
);
72 * Mount union filesystem
75 union_mount(struct mount
*mp
, char *path
, caddr_t data
, struct ucred
*cred
)
78 struct union_args args
;
79 struct vnode
*lowerrootvp
= NULLVP
;
80 struct vnode
*upperrootvp
= NULLVP
;
81 struct union_mount
*um
= 0;
82 struct ucred
*cred
= 0;
83 struct nlookupdata nd
;
88 UDEBUG(("union_mount(mp = %p)\n", (void *)mp
));
91 * Disable clustered write, otherwise system becomes unstable.
93 mp
->mnt_flag
|= MNT_NOCLUSTERW
;
98 if (mp
->mnt_flag
& MNT_UPDATE
) {
101 * 1. a way to convert between rdonly and rdwr mounts.
102 * 2. support for nfs exports.
111 error
= copyin(data
, (caddr_t
)&args
, sizeof(struct union_args
));
116 * Obtain lower vnode.
119 lowerrootvp
= mp
->mnt_vnodecovered
;
124 * Unlock lower node to avoid deadlock.
126 if (lowerrootvp
->v_tag
== VT_UNION
)
127 vn_unlock(lowerrootvp
);
131 * Obtain upper vnode by calling nlookup() on the path. The
132 * upperrootvp will be turned referenced but not locked.
134 error
= nlookup_init(&nd
, args
.target
, UIO_USERSPACE
, NLC_FOLLOW
);
136 error
= nlookup(&nd
);
138 error
= cache_vref(&nd
.nl_nch
, nd
.nl_cred
, &upperrootvp
);
143 UDEBUG(("mount_root UPPERVP %p locked = %d\n", upperrootvp
,
144 vn_islocked(upperrootvp
)));
147 * Check multi union mount to avoid `lock myself again' panic.
148 * Also require that it be a directory.
150 if (upperrootvp
== VTOUNION(lowerrootvp
)->un_uppervp
) {
152 kprintf("union_mount: multi union mount?\n");
158 if (upperrootvp
->v_type
!= VDIR
) {
164 * Allocate our union_mount structure and populate the fields.
165 * The vnode references are stored in the union_mount as held,
166 * unlocked references. Depending on the _BELOW flag, the
167 * filesystems are viewed in a different order. In effect this
168 * is the same as providing a mount-under option to the mount
172 um
= (struct union_mount
*) malloc(sizeof(struct union_mount
),
173 M_UNIONFSMNT
, M_WAITOK
);
175 bzero(um
, sizeof(struct union_mount
));
177 um
->um_op
= args
.mntflags
& UNMNT_OPMASK
;
181 um
->um_lowervp
= lowerrootvp
;
182 um
->um_uppervp
= upperrootvp
;
188 um
->um_lowervp
= upperrootvp
;
189 um
->um_uppervp
= lowerrootvp
;
197 um
->um_uppervp
= upperrootvp
;
198 um
->um_lowervp
= lowerrootvp
;
208 * Unless the mount is readonly, ensure that the top layer
209 * supports whiteout operations
211 if ((mp
->mnt_flag
& MNT_RDONLY
) == 0) {
212 error
= VOP_WHITEOUT(um
->um_uppervp
, NULL
, NAMEI_LOOKUP
);
218 * File creds and modes for shadowed files are based on the user
219 * that did the mount.
221 um
->um_cred
= crhold(cred
);
222 um
->um_cmode
= UN_DIRMODE
;
224 um
->um_cmode
&= ~curproc
->p_fd
->fd_cmask
;
227 * Depending on what you think the MNT_LOCAL flag might mean,
228 * you may want the && to be || on the conditional below.
229 * At the moment it has been defined that the filesystem is
230 * only local if it is all local, ie the MNT_LOCAL flag implies
231 * that the entire namespace is local. If you think the MNT_LOCAL
232 * flag implies that some of the files might be stored locally
233 * then you will want to change the conditional.
235 if (um
->um_op
== UNMNT_ABOVE
) {
236 if (((um
->um_lowervp
== NULLVP
) ||
237 (um
->um_lowervp
->v_mount
->mnt_flag
& MNT_LOCAL
)) &&
238 (um
->um_uppervp
->v_mount
->mnt_flag
& MNT_LOCAL
))
239 mp
->mnt_flag
|= MNT_LOCAL
;
243 * Copy in the upper layer's RDONLY flag. This is for the benefit
244 * of lookup() which explicitly checks the flag, rather than asking
245 * the filesystem for its own opinion. This means, that an update
246 * mount of the underlying filesystem to go from rdonly to rdwr
247 * will leave the unioned view as read-only.
249 mp
->mnt_flag
|= (um
->um_uppervp
->v_mount
->mnt_flag
& MNT_RDONLY
);
251 mp
->mnt_data
= (qaddr_t
) um
;
266 bcopy(cp
, mp
->mnt_stat
.f_mntfromname
, len
);
268 cp
= mp
->mnt_stat
.f_mntfromname
+ len
;
269 len
= MNAMELEN
- len
;
271 (void) copyinstr(args
.target
, cp
, len
- 1, &size
);
272 bzero(cp
+ size
, len
- size
);
274 vfs_add_vnodeops(mp
, &union_vnode_vops
, &mp
->mnt_vn_norm_ops
);
276 (void)union_statfs(mp
, &mp
->mnt_stat
, cred
);
283 vrele(um
->um_uppervp
);
285 vrele(um
->um_lowervp
);
286 /* XXX other fields */
287 kfree(um
, M_UNIONFSMNT
);
299 * Free reference to union layer
302 union_unmount(struct mount
*mp
, int mntflags
)
304 struct union_mount
*um
= MOUNTTOUNIONMOUNT(mp
);
309 UDEBUG(("union_unmount(mp = %p)\n", (void *)mp
));
311 if (mntflags
& MNT_FORCE
)
315 * Keep flushing vnodes from the mount list.
316 * This is needed because of the un_pvp held
317 * reference to the parent vnode.
318 * If more vnodes have been freed on a given pass,
319 * the try again. The loop will iterate at most
320 * (d) times, where (d) is the maximum tree depth
323 for (freeing
= 0; (error
= vflush(mp
, 0, flags
)) != 0;) {
324 int n
= mp
->mnt_nvnodelistsize
;
326 /* if this is unchanged then stop */
330 /* otherwise try once more time */
334 /* If the most recent vflush failed, the filesystem is still busy. */
339 * Discard references to upper and lower target vnodes.
342 vrele(um
->um_lowervp
);
343 vrele(um
->um_uppervp
);
346 * Finally, throw away the union_mount structure
348 kfree(mp
->mnt_data
, M_UNIONFSMNT
); /* XXX */
354 union_root(struct mount
*mp
, struct vnode
**vpp
)
356 struct union_mount
*um
= MOUNTTOUNIONMOUNT(mp
);
360 * Supply an unlocked reference to um_uppervp and to um_lowervp. It
361 * is possible for um_uppervp to be locked without the associated
362 * root union_node being locked. We let union_allocvp() deal with
365 UDEBUG(("union_root UPPERVP %p locked = %d\n", um
->um_uppervp
,
366 vn_islocked(um
->um_uppervp
)));
368 vref(um
->um_uppervp
);
370 vref(um
->um_lowervp
);
372 error
= union_allocvp(vpp
, mp
, NULLVP
, NULLVP
, NULL
,
373 um
->um_uppervp
, um
->um_lowervp
, 1);
374 UDEBUG(("error %d\n", error
));
375 UDEBUG(("union_root2 UPPERVP %p locked = %d\n", um
->um_uppervp
,
376 vn_islocked(um
->um_uppervp
)));
382 union_statfs(struct mount
*mp
, struct statfs
*sbp
, struct ucred
*cred
)
385 struct union_mount
*um
= MOUNTTOUNIONMOUNT(mp
);
389 UDEBUG(("union_statfs(mp = %p, lvp = %p, uvp = %p)\n",
390 (void *)mp
, (void *)um
->um_lowervp
, (void *)um
->um_uppervp
));
392 bzero(&mstat
, sizeof(mstat
));
394 if (um
->um_lowervp
) {
395 error
= VFS_STATFS(um
->um_lowervp
->v_mount
, &mstat
, cred
);
400 /* now copy across the "interesting" information and fake the rest */
402 sbp
->f_type
= mstat
.f_type
;
403 sbp
->f_flags
= mstat
.f_flags
;
404 sbp
->f_bsize
= mstat
.f_bsize
;
405 sbp
->f_iosize
= mstat
.f_iosize
;
407 lbsize
= mstat
.f_bsize
;
408 sbp
->f_blocks
= mstat
.f_blocks
;
409 sbp
->f_bfree
= mstat
.f_bfree
;
410 sbp
->f_bavail
= mstat
.f_bavail
;
411 sbp
->f_files
= mstat
.f_files
;
412 sbp
->f_ffree
= mstat
.f_ffree
;
414 error
= VFS_STATFS(um
->um_uppervp
->v_mount
, &mstat
, cred
);
418 sbp
->f_flags
= mstat
.f_flags
;
419 sbp
->f_bsize
= mstat
.f_bsize
;
420 sbp
->f_iosize
= mstat
.f_iosize
;
423 * if the lower and upper blocksizes differ, then frig the
424 * block counts so that the sizes reported by df make some
425 * kind of sense. none of this makes sense though.
428 if (mstat
.f_bsize
!= lbsize
)
429 sbp
->f_blocks
= ((off_t
) sbp
->f_blocks
* lbsize
) / mstat
.f_bsize
;
432 * The "total" fields count total resources in all layers,
433 * the "free" fields count only those resources which are
434 * free in the upper layer (since only the upper layer
437 sbp
->f_blocks
+= mstat
.f_blocks
;
438 sbp
->f_bfree
= mstat
.f_bfree
;
439 sbp
->f_bavail
= mstat
.f_bavail
;
440 sbp
->f_files
+= mstat
.f_files
;
441 sbp
->f_ffree
= mstat
.f_ffree
;
443 if (sbp
!= &mp
->mnt_stat
) {
444 sbp
->f_type
= mp
->mnt_vfc
->vfc_typenum
;
445 bcopy(&mp
->mnt_stat
.f_fsid
, &sbp
->f_fsid
, sizeof(sbp
->f_fsid
));
446 bcopy(mp
->mnt_stat
.f_mntfromname
, sbp
->f_mntfromname
, MNAMELEN
);
451 static struct vfsops union_vfsops
= {
452 .vfs_mount
= union_mount
,
453 .vfs_unmount
= union_unmount
,
454 .vfs_root
= union_root
,
455 .vfs_statfs
= union_statfs
,
456 .vfs_sync
= vfs_stdsync
,
457 .vfs_init
= union_init
460 VFS_SET(union_vfsops
, union, VFCF_LOOPBACK
);