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umap_vfsops.c revision 1.56
      1 /*	$NetBSD: umap_vfsops.c,v 1.56 2005/12/11 12:24:51 christos 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 1.56 2005/12/11 12:24:51 christos 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 <miscfs/umapfs/umap.h>
     56 #include <miscfs/genfs/layer_extern.h>
     57 
     58 int	umapfs_mount(struct mount *, const char *, void *,
     59 			  struct nameidata *, struct lwp *);
     60 int	umapfs_unmount(struct mount *, int, struct lwp *);
     61 
     62 /*
     63  * Mount umap layer
     64  */
     65 int
     66 umapfs_mount(mp, path, data, ndp, l)
     67 	struct mount *mp;
     68 	const char *path;
     69 	void *data;
     70 	struct nameidata *ndp;
     71 	struct lwp *l;
     72 {
     73 	struct umap_args args;
     74 	struct vnode *lowerrootvp, *vp;
     75 	struct umap_mount *amp;
     76 	struct proc *p = l->l_proc;
     77 	int error;
     78 #ifdef UMAPFS_DIAGNOSTIC
     79 	int i;
     80 #endif
     81 
     82 	if (mp->mnt_flag & MNT_GETARGS) {
     83 		amp = MOUNTTOUMAPMOUNT(mp);
     84 		if (amp == NULL)
     85 			return EIO;
     86 		args.la.target = NULL;
     87 		args.nentries = amp->info_nentries;
     88 		args.gnentries = amp->info_gnentries;
     89 		return copyout(&args, data, sizeof(args));
     90 	}
     91 
     92 	/* only for root */
     93 	if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
     94 		return error;
     95 
     96 #ifdef UMAPFS_DIAGNOSTIC
     97 	printf("umapfs_mount(mp = %p)\n", mp);
     98 #endif
     99 
    100 	/*
    101 	 * Get argument
    102 	 */
    103 	error = copyin(data, &args, sizeof(struct umap_args));
    104 	if (error)
    105 		return (error);
    106 
    107 	/*
    108 	 * Update is not supported
    109 	 */
    110 	if (mp->mnt_flag & MNT_UPDATE)
    111 		return EOPNOTSUPP;
    112 
    113 	/*
    114 	 * Find lower node
    115 	 */
    116 	NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF,
    117 		UIO_USERSPACE, args.umap_target, l);
    118 	if ((error = namei(ndp)) != 0)
    119 		return (error);
    120 
    121 	/*
    122 	 * Sanity check on lower vnode
    123 	 */
    124 	lowerrootvp = ndp->ni_vp;
    125 #ifdef UMAPFS_DIAGNOSTIC
    126 	printf("vp = %p, check for VDIR...\n", lowerrootvp);
    127 #endif
    128 
    129 	if (lowerrootvp->v_type != VDIR) {
    130 		vput(lowerrootvp);
    131 		return (EINVAL);
    132 	}
    133 
    134 #ifdef UMAPFS_DIAGNOSTIC
    135 	printf("mp = %p\n", mp);
    136 #endif
    137 
    138 	amp = (struct umap_mount *) malloc(sizeof(struct umap_mount),
    139 				M_UFSMNT, M_WAITOK);	/* XXX */
    140 	memset(amp, 0, sizeof(struct umap_mount));
    141 
    142 	mp->mnt_data = amp;
    143 	mp->mnt_leaf = lowerrootvp->v_mount->mnt_leaf;
    144 	amp->umapm_vfs = lowerrootvp->v_mount;
    145 	if (amp->umapm_vfs->mnt_flag & MNT_LOCAL)
    146 		mp->mnt_flag |= MNT_LOCAL;
    147 
    148 	/*
    149 	 * Now copy in the number of entries and maps for umap mapping.
    150 	 */
    151 	if (args.nentries > MAPFILEENTRIES || args.gnentries > GMAPFILEENTRIES) {
    152 		vput(lowerrootvp);
    153 		return (error);
    154 	}
    155 
    156 	amp->info_nentries = args.nentries;
    157 	amp->info_gnentries = args.gnentries;
    158 	error = copyin(args.mapdata, amp->info_mapdata,
    159 	    2*sizeof(u_long)*args.nentries);
    160 	if (error) {
    161 		vput(lowerrootvp);
    162 		return (error);
    163 	}
    164 
    165 #ifdef UMAPFS_DIAGNOSTIC
    166 	printf("umap_mount:nentries %d\n",args.nentries);
    167 	for (i = 0; i < args.nentries; i++)
    168 		printf("   %ld maps to %ld\n", amp->info_mapdata[i][0],
    169 	 	    amp->info_mapdata[i][1]);
    170 #endif
    171 
    172 	error = copyin(args.gmapdata, amp->info_gmapdata,
    173 	    2*sizeof(u_long)*args.gnentries);
    174 	if (error) {
    175 		vput(lowerrootvp);
    176 		return (error);
    177 	}
    178 
    179 #ifdef UMAPFS_DIAGNOSTIC
    180 	printf("umap_mount:gnentries %d\n",args.gnentries);
    181 	for (i = 0; i < args.gnentries; i++)
    182 		printf("\tgroup %ld maps to %ld\n",
    183 		    amp->info_gmapdata[i][0],
    184 	 	    amp->info_gmapdata[i][1]);
    185 #endif
    186 
    187 	/*
    188 	 * Make sure the mount point's sufficiently initialized
    189 	 * that the node create call will work.
    190 	 */
    191 	vfs_getnewfsid(mp);
    192 	amp->umapm_size = sizeof(struct umap_node);
    193 	amp->umapm_tag = VT_UMAP;
    194 	amp->umapm_bypass = umap_bypass;
    195 	amp->umapm_alloc = layer_node_alloc;	/* the default alloc is fine */
    196 	amp->umapm_vnodeop_p = umap_vnodeop_p;
    197 	simple_lock_init(&amp->umapm_hashlock);
    198 	amp->umapm_node_hashtbl = hashinit(NUMAPNODECACHE, HASH_LIST, M_CACHE,
    199 	    M_WAITOK, &amp->umapm_node_hash);
    200 
    201 
    202 	/*
    203 	 * fix up umap node for root vnode.
    204 	 */
    205 	error = layer_node_create(mp, lowerrootvp, &vp);
    206 	/*
    207 	 * Make sure the node alias worked
    208 	 */
    209 	if (error) {
    210 		vput(lowerrootvp);
    211 		free(amp, M_UFSMNT);	/* XXX */
    212 		return (error);
    213 	}
    214 	/*
    215 	 * Unlock the node (either the lower or the alias)
    216 	 */
    217 	VOP_UNLOCK(vp, 0);
    218 
    219 	/*
    220 	 * Keep a held reference to the root vnode.
    221 	 * It is vrele'd in umapfs_unmount.
    222 	 */
    223 	vp->v_flag |= VROOT;
    224 	amp->umapm_rootvp = vp;
    225 
    226 	error = set_statvfs_info(path, UIO_USERSPACE, args.umap_target,
    227 	    UIO_USERSPACE, mp, l);
    228 #ifdef UMAPFS_DIAGNOSTIC
    229 	printf("umapfs_mount: lower %s, alias at %s\n",
    230 		mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
    231 #endif
    232 	return error;
    233 }
    234 
    235 /*
    236  * Free reference to umap layer
    237  */
    238 int
    239 umapfs_unmount(mp, mntflags, l)
    240 	struct mount *mp;
    241 	int mntflags;
    242 	struct lwp *l;
    243 {
    244 	struct vnode *rtvp = MOUNTTOUMAPMOUNT(mp)->umapm_rootvp;
    245 	int error;
    246 	int flags = 0;
    247 
    248 #ifdef UMAPFS_DIAGNOSTIC
    249 	printf("umapfs_unmount(mp = %p)\n", mp);
    250 #endif
    251 
    252 	if (mntflags & MNT_FORCE)
    253 		flags |= FORCECLOSE;
    254 
    255 	/*
    256 	 * Clear out buffer cache.  I don't think we
    257 	 * ever get anything cached at this level at the
    258 	 * moment, but who knows...
    259 	 */
    260 #ifdef notyet
    261 	mntflushbuf(mp, 0);
    262 	if (mntinvalbuf(mp, 1))
    263 		return (EBUSY);
    264 #endif
    265 	if (rtvp->v_usecount > 1)
    266 		return (EBUSY);
    267 	if ((error = vflush(mp, rtvp, flags)) != 0)
    268 		return (error);
    269 
    270 #ifdef UMAPFS_DIAGNOSTIC
    271 	vprint("alias root of lower", rtvp);
    272 #endif
    273 	/*
    274 	 * Release reference on underlying root vnode
    275 	 */
    276 	vrele(rtvp);
    277 	/*
    278 	 * And blow it away for future re-use
    279 	 */
    280 	vgone(rtvp);
    281 	/*
    282 	 * Finally, throw away the umap_mount structure
    283 	 */
    284 	free(mp->mnt_data, M_UFSMNT);	/* XXX */
    285 	mp->mnt_data = 0;
    286 	return (0);
    287 }
    288 
    289 SYSCTL_SETUP(sysctl_vfs_umap_setup, "sysctl vfs.umap subtree setup")
    290 {
    291 
    292 	sysctl_createv(clog, 0, NULL, NULL,
    293 		       CTLFLAG_PERMANENT,
    294 		       CTLTYPE_NODE, "vfs", NULL,
    295 		       NULL, 0, NULL, 0,
    296 		       CTL_VFS, CTL_EOL);
    297 	sysctl_createv(clog, 0, NULL, NULL,
    298 		       CTLFLAG_PERMANENT,
    299 		       CTLTYPE_NODE, "umap",
    300 		       SYSCTL_DESCR("UID/GID remapping file system"),
    301 		       NULL, 0, NULL, 0,
    302 		       CTL_VFS, 10, CTL_EOL);
    303 	/*
    304 	 * XXX the "10" above could be dynamic, thereby eliminating
    305 	 * one more instance of the "number to vfs" mapping problem,
    306 	 * but "10" is the order as taken from sys/mount.h
    307 	 */
    308 }
    309 
    310 extern const struct vnodeopv_desc umapfs_vnodeop_opv_desc;
    311 
    312 const struct vnodeopv_desc * const umapfs_vnodeopv_descs[] = {
    313 	&umapfs_vnodeop_opv_desc,
    314 	NULL,
    315 };
    316 
    317 struct vfsops umapfs_vfsops = {
    318 	MOUNT_UMAP,
    319 	umapfs_mount,
    320 	layerfs_start,
    321 	umapfs_unmount,
    322 	layerfs_root,
    323 	layerfs_quotactl,
    324 	layerfs_statvfs,
    325 	layerfs_sync,
    326 	layerfs_vget,
    327 	layerfs_fhtovp,
    328 	layerfs_vptofh,
    329 	layerfs_init,
    330 	NULL,
    331 	layerfs_done,
    332 	NULL,				/* vfs_mountroot */
    333 	layerfs_snapshot,
    334 	vfs_stdextattrctl,
    335 	umapfs_vnodeopv_descs,
    336 };
    337 VFS_ATTACH(umapfs_vfsops);
    338