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umap_vfsops.c revision 1.65
      1 /*	$NetBSD: umap_vfsops.c,v 1.65 2007/07/08 23:58:53 pooka Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software donated to Berkeley by
      8  * the UCLA Ficus project.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  *	from: @(#)null_vfsops.c       1.5 (Berkeley) 7/10/92
     35  *	@(#)umap_vfsops.c	8.8 (Berkeley) 5/14/95
     36  */
     37 
     38 /*
     39  * Umap Layer
     40  * (See mount_umap(8) for a description of this layer.)
     41  */
     42 
     43 #include <sys/cdefs.h>
     44 __KERNEL_RCSID(0, "$NetBSD: umap_vfsops.c,v 1.65 2007/07/08 23:58:53 pooka Exp $");
     45 
     46 #include <sys/param.h>
     47 #include <sys/systm.h>
     48 #include <sys/sysctl.h>
     49 #include <sys/proc.h>
     50 #include <sys/time.h>
     51 #include <sys/vnode.h>
     52 #include <sys/mount.h>
     53 #include <sys/namei.h>
     54 #include <sys/malloc.h>
     55 #include <sys/kauth.h>
     56 
     57 #include <miscfs/umapfs/umap.h>
     58 #include <miscfs/genfs/layer_extern.h>
     59 
     60 int	umapfs_mount(struct mount *, const char *, void *,
     61 			  struct nameidata *, struct lwp *);
     62 int	umapfs_unmount(struct mount *, int, struct lwp *);
     63 
     64 /*
     65  * Mount umap layer
     66  */
     67 int
     68 umapfs_mount(mp, path, data, ndp, l)
     69 	struct mount *mp;
     70 	const char *path;
     71 	void *data;
     72 	struct nameidata *ndp;
     73 	struct lwp *l;
     74 {
     75 	struct umap_args args;
     76 	struct vnode *lowerrootvp, *vp;
     77 	struct umap_mount *amp;
     78 	int error;
     79 #ifdef UMAPFS_DIAGNOSTIC
     80 	int i;
     81 #endif
     82 
     83 	if (mp->mnt_flag & MNT_GETARGS) {
     84 		amp = MOUNTTOUMAPMOUNT(mp);
     85 		if (amp == NULL)
     86 			return EIO;
     87 		args.la.target = NULL;
     88 		args.nentries = amp->info_nentries;
     89 		args.gnentries = amp->info_gnentries;
     90 		return copyout(&args, data, sizeof(args));
     91 	}
     92 
     93 	/* only for root */
     94 	if ((error = kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
     95 	    NULL)) != 0)
     96 		return error;
     97 
     98 #ifdef UMAPFS_DIAGNOSTIC
     99 	printf("umapfs_mount(mp = %p)\n", mp);
    100 #endif
    101 
    102 	/*
    103 	 * Get argument
    104 	 */
    105 	error = copyin(data, &args, sizeof(struct umap_args));
    106 	if (error)
    107 		return (error);
    108 
    109 	/*
    110 	 * Update is not supported
    111 	 */
    112 	if (mp->mnt_flag & MNT_UPDATE)
    113 		return EOPNOTSUPP;
    114 
    115 	/*
    116 	 * Find lower node
    117 	 */
    118 	NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF,
    119 		UIO_USERSPACE, args.umap_target, l);
    120 	if ((error = namei(ndp)) != 0)
    121 		return (error);
    122 
    123 	/*
    124 	 * Sanity check on lower vnode
    125 	 */
    126 	lowerrootvp = ndp->ni_vp;
    127 #ifdef UMAPFS_DIAGNOSTIC
    128 	printf("vp = %p, check for VDIR...\n", lowerrootvp);
    129 #endif
    130 
    131 	if (lowerrootvp->v_type != VDIR) {
    132 		vput(lowerrootvp);
    133 		return (EINVAL);
    134 	}
    135 
    136 #ifdef UMAPFS_DIAGNOSTIC
    137 	printf("mp = %p\n", mp);
    138 #endif
    139 
    140 	amp = (struct umap_mount *) malloc(sizeof(struct umap_mount),
    141 				M_UFSMNT, M_WAITOK);	/* XXX */
    142 	memset(amp, 0, sizeof(struct umap_mount));
    143 
    144 	mp->mnt_data = amp;
    145 	amp->umapm_vfs = lowerrootvp->v_mount;
    146 	if (amp->umapm_vfs->mnt_flag & MNT_LOCAL)
    147 		mp->mnt_flag |= MNT_LOCAL;
    148 
    149 	/*
    150 	 * Now copy in the number of entries and maps for umap mapping.
    151 	 */
    152 	if (args.nentries > MAPFILEENTRIES || args.gnentries > GMAPFILEENTRIES) {
    153 		vput(lowerrootvp);
    154 		return (error);
    155 	}
    156 
    157 	amp->info_nentries = args.nentries;
    158 	amp->info_gnentries = args.gnentries;
    159 	error = copyin(args.mapdata, amp->info_mapdata,
    160 	    2*sizeof(u_long)*args.nentries);
    161 	if (error) {
    162 		vput(lowerrootvp);
    163 		return (error);
    164 	}
    165 
    166 #ifdef UMAPFS_DIAGNOSTIC
    167 	printf("umap_mount:nentries %d\n",args.nentries);
    168 	for (i = 0; i < args.nentries; i++)
    169 		printf("   %ld maps to %ld\n", amp->info_mapdata[i][0],
    170 	 	    amp->info_mapdata[i][1]);
    171 #endif
    172 
    173 	error = copyin(args.gmapdata, amp->info_gmapdata,
    174 	    2*sizeof(u_long)*args.gnentries);
    175 	if (error) {
    176 		vput(lowerrootvp);
    177 		return (error);
    178 	}
    179 
    180 #ifdef UMAPFS_DIAGNOSTIC
    181 	printf("umap_mount:gnentries %d\n",args.gnentries);
    182 	for (i = 0; i < args.gnentries; i++)
    183 		printf("\tgroup %ld maps to %ld\n",
    184 		    amp->info_gmapdata[i][0],
    185 	 	    amp->info_gmapdata[i][1]);
    186 #endif
    187 
    188 	/*
    189 	 * Make sure the mount point's sufficiently initialized
    190 	 * that the node create call will work.
    191 	 */
    192 	vfs_getnewfsid(mp);
    193 	amp->umapm_size = sizeof(struct umap_node);
    194 	amp->umapm_tag = VT_UMAP;
    195 	amp->umapm_bypass = umap_bypass;
    196 	amp->umapm_alloc = layer_node_alloc;	/* the default alloc is fine */
    197 	amp->umapm_vnodeop_p = umap_vnodeop_p;
    198 	simple_lock_init(&amp->umapm_hashlock);
    199 	amp->umapm_node_hashtbl = hashinit(NUMAPNODECACHE, HASH_LIST, M_CACHE,
    200 	    M_WAITOK, &amp->umapm_node_hash);
    201 
    202 
    203 	/*
    204 	 * fix up umap node for root vnode.
    205 	 */
    206 	error = layer_node_create(mp, lowerrootvp, &vp);
    207 	/*
    208 	 * Make sure the node alias worked
    209 	 */
    210 	if (error) {
    211 		vput(lowerrootvp);
    212 		free(amp, M_UFSMNT);	/* XXX */
    213 		return (error);
    214 	}
    215 	/*
    216 	 * Unlock the node (either the lower or the alias)
    217 	 */
    218 	VOP_UNLOCK(vp, 0);
    219 
    220 	/*
    221 	 * Keep a held reference to the root vnode.
    222 	 * It is vrele'd in umapfs_unmount.
    223 	 */
    224 	vp->v_flag |= VROOT;
    225 	amp->umapm_rootvp = vp;
    226 
    227 	error = set_statvfs_info(path, UIO_USERSPACE, args.umap_target,
    228 	    UIO_USERSPACE, mp, l);
    229 #ifdef UMAPFS_DIAGNOSTIC
    230 	printf("umapfs_mount: lower %s, alias at %s\n",
    231 		mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
    232 #endif
    233 	return error;
    234 }
    235 
    236 /*
    237  * Free reference to umap layer
    238  */
    239 int
    240 umapfs_unmount(struct mount *mp, int mntflags, struct lwp *l)
    241 {
    242 	struct vnode *rtvp = MOUNTTOUMAPMOUNT(mp)->umapm_rootvp;
    243 	int error;
    244 	int flags = 0;
    245 
    246 #ifdef UMAPFS_DIAGNOSTIC
    247 	printf("umapfs_unmount(mp = %p)\n", mp);
    248 #endif
    249 
    250 	if (mntflags & MNT_FORCE)
    251 		flags |= FORCECLOSE;
    252 
    253 	if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
    254 		return (EBUSY);
    255 	if ((error = vflush(mp, rtvp, flags)) != 0)
    256 		return (error);
    257 
    258 #ifdef UMAPFS_DIAGNOSTIC
    259 	vprint("alias root of lower", rtvp);
    260 #endif
    261 	/*
    262 	 * Release reference on underlying root vnode
    263 	 */
    264 	vrele(rtvp);
    265 	/*
    266 	 * And blow it away for future re-use
    267 	 */
    268 	vgone(rtvp);
    269 	/*
    270 	 * Finally, throw away the umap_mount structure
    271 	 */
    272 	free(mp->mnt_data, M_UFSMNT);	/* XXX */
    273 	mp->mnt_data = 0;
    274 	return (0);
    275 }
    276 
    277 SYSCTL_SETUP(sysctl_vfs_umap_setup, "sysctl vfs.umap subtree setup")
    278 {
    279 
    280 	sysctl_createv(clog, 0, NULL, NULL,
    281 		       CTLFLAG_PERMANENT,
    282 		       CTLTYPE_NODE, "vfs", NULL,
    283 		       NULL, 0, NULL, 0,
    284 		       CTL_VFS, CTL_EOL);
    285 	sysctl_createv(clog, 0, NULL, NULL,
    286 		       CTLFLAG_PERMANENT,
    287 		       CTLTYPE_NODE, "umap",
    288 		       SYSCTL_DESCR("UID/GID remapping file system"),
    289 		       NULL, 0, NULL, 0,
    290 		       CTL_VFS, 10, CTL_EOL);
    291 	/*
    292 	 * XXX the "10" above could be dynamic, thereby eliminating
    293 	 * one more instance of the "number to vfs" mapping problem,
    294 	 * but "10" is the order as taken from sys/mount.h
    295 	 */
    296 }
    297 
    298 extern const struct vnodeopv_desc umapfs_vnodeop_opv_desc;
    299 
    300 const struct vnodeopv_desc * const umapfs_vnodeopv_descs[] = {
    301 	&umapfs_vnodeop_opv_desc,
    302 	NULL,
    303 };
    304 
    305 struct vfsops umapfs_vfsops = {
    306 	MOUNT_UMAP,
    307 	umapfs_mount,
    308 	layerfs_start,
    309 	umapfs_unmount,
    310 	layerfs_root,
    311 	layerfs_quotactl,
    312 	layerfs_statvfs,
    313 	layerfs_sync,
    314 	layerfs_vget,
    315 	layerfs_fhtovp,
    316 	layerfs_vptofh,
    317 	layerfs_init,
    318 	NULL,
    319 	layerfs_done,
    320 	NULL,				/* vfs_mountroot */
    321 	layerfs_snapshot,
    322 	vfs_stdextattrctl,
    323 	vfs_stdsuspendctl,
    324 	umapfs_vnodeopv_descs,
    325 	0,				/* vfs_refcount */
    326 	{ NULL, NULL },
    327 };
    328 VFS_ATTACH(umapfs_vfsops);
    329