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Annotation of src/sys/miscfs/nullfs/null_vfsops.c, Revision 1.31

1.31    ! assar       1: /*     $NetBSD: null_vfsops.c,v 1.30 2001/06/07 13:44:46 wiz Exp $     */
1.2       cgd         2:
1.1       mycroft     3: /*
1.24      wrstuden    4:  * Copyright (c) 1999 National Aeronautics & Space Administration
                      5:  * All rights reserved.
                      6:  *
                      7:  * This software was written by William Studenmund of the
1.30      wiz         8:  * Numerical Aerospace Simulation Facility, NASA Ames Research Center.
1.24      wrstuden    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.
1.25      soren      18:  * 3. Neither the name of the National Aeronautics & Space Administration
1.24      wrstuden   19:  *    nor the names of its contributors may be used to endorse or promote
                     20:  *    products derived from this software without specific prior written
                     21:  *    permission.
                     22:  *
                     23:  * THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION
                     24:  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
                     25:  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
                     26:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB-
                     27:  * UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
                     28:  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
                     29:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
                     30:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
                     31:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
                     32:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
                     33:  * POSSIBILITY OF SUCH DAMAGE.
                     34:  */
                     35: /*
1.19      fvdl       36:  * Copyright (c) 1992, 1993, 1995
1.1       mycroft    37:  *     The Regents of the University of California.  All rights reserved.
                     38:  *
                     39:  * This code is derived from software donated to Berkeley by
                     40:  * Jan-Simon Pendry.
                     41:  *
                     42:  * Redistribution and use in source and binary forms, with or without
                     43:  * modification, are permitted provided that the following conditions
                     44:  * are met:
                     45:  * 1. Redistributions of source code must retain the above copyright
                     46:  *    notice, this list of conditions and the following disclaimer.
                     47:  * 2. Redistributions in binary form must reproduce the above copyright
                     48:  *    notice, this list of conditions and the following disclaimer in the
                     49:  *    documentation and/or other materials provided with the distribution.
                     50:  * 3. All advertising materials mentioning features or use of this software
                     51:  *    must display the following acknowledgement:
                     52:  *     This product includes software developed by the University of
                     53:  *     California, Berkeley and its contributors.
                     54:  * 4. Neither the name of the University nor the names of its contributors
                     55:  *    may be used to endorse or promote products derived from this software
                     56:  *    without specific prior written permission.
                     57:  *
                     58:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     59:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     60:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     61:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     62:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     63:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     64:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     65:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     66:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     67:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     68:  * SUCH DAMAGE.
                     69:  *
                     70:  *     from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp
                     71:  *     from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
1.19      fvdl       72:  *     @(#)null_vfsops.c       8.7 (Berkeley) 5/14/95
1.1       mycroft    73:  */
                     74:
                     75: /*
                     76:  * Null Layer
                     77:  * (See null_vnops.c for a description of what this does.)
                     78:  */
                     79:
                     80: #include <sys/param.h>
                     81: #include <sys/systm.h>
                     82: #include <sys/time.h>
1.19      fvdl       83: #include <sys/proc.h>
1.1       mycroft    84: #include <sys/types.h>
                     85: #include <sys/vnode.h>
                     86: #include <sys/mount.h>
                     87: #include <sys/namei.h>
                     88: #include <sys/malloc.h>
                     89: #include <miscfs/nullfs/null.h>
1.24      wrstuden   90: #include <miscfs/genfs/layer_extern.h>
1.1       mycroft    91:
1.14      cgd        92: int    nullfs_mount __P((struct mount *, const char *, void *,
1.10      christos   93:                          struct nameidata *, struct proc *));
                     94: int    nullfs_unmount __P((struct mount *, int, struct proc *));
1.24      wrstuden   95:
                     96: #define        NNULLNODECACHE  16
                     97:
1.1       mycroft    98: /*
                     99:  * Mount null layer
                    100:  */
                    101: int
                    102: nullfs_mount(mp, path, data, ndp, p)
                    103:        struct mount *mp;
1.14      cgd       104:        const char *path;
                    105:        void *data;
1.1       mycroft   106:        struct nameidata *ndp;
                    107:        struct proc *p;
                    108: {
                    109:        int error = 0;
                    110:        struct null_args args;
                    111:        struct vnode *lowerrootvp, *vp;
1.24      wrstuden  112:        struct null_mount *nmp;
                    113:        struct layer_mount *lmp;
1.8       mycroft   114:        size_t size;
1.1       mycroft   115:
                    116: #ifdef NULLFS_DIAGNOSTIC
1.16      christos  117:        printf("nullfs_mount(mp = %p)\n", mp);
1.1       mycroft   118: #endif
                    119:
                    120:        /*
                    121:         * Get argument
                    122:         */
1.10      christos  123:        error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
                    124:        if (error)
1.1       mycroft   125:                return (error);
                    126:
                    127:        /*
1.24      wrstuden  128:         * Update only does export updating.
                    129:         */
                    130:        if (mp->mnt_flag & MNT_UPDATE) {
                    131:                lmp = MOUNTTOLAYERMOUNT(mp);
                    132:                if (args.nulla_target == 0)
                    133:                        return (vfs_export(mp, &lmp->layerm_export,
                    134:                                        &args.la.export));
                    135:                else
                    136:                        return (EOPNOTSUPP);
                    137:        }
                    138:
                    139:        /*
1.1       mycroft   140:         * Find lower node
                    141:         */
1.31    ! assar     142:        NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF,
1.24      wrstuden  143:                UIO_USERSPACE, args.la.target, p);
1.10      christos  144:        if ((error = namei(ndp)) != 0)
1.1       mycroft   145:                return (error);
                    146:
                    147:        /*
                    148:         * Sanity check on lower vnode
                    149:         */
                    150:        lowerrootvp = ndp->ni_vp;
                    151:
1.24      wrstuden  152:        /*
                    153:         * First cut at fixing up upper mount point
                    154:         */
                    155:        nmp = (struct null_mount *) malloc(sizeof(struct null_mount),
1.1       mycroft   156:                                M_UFSMNT, M_WAITOK);    /* XXX */
1.24      wrstuden  157:        memset((caddr_t)nmp, 0, sizeof(struct null_mount));
                    158:
                    159:        mp->mnt_data = (qaddr_t) nmp;
                    160:        nmp->nullm_vfs = lowerrootvp->v_mount;
                    161:        if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL)
                    162:                mp->mnt_flag |= MNT_LOCAL;
1.1       mycroft   163:
                    164:        /*
1.24      wrstuden  165:         * Make sure that the mount point is sufficiently initialized
                    166:         * that the node create call will work.
1.1       mycroft   167:         */
1.27      assar     168:        vfs_getnewfsid(mp);
1.24      wrstuden  169:
                    170:        nmp->nullm_size = sizeof (struct null_node);
                    171:        nmp->nullm_tag = VT_NULL;
                    172:        nmp->nullm_bypass = layer_bypass;
                    173:        nmp->nullm_alloc = layer_node_alloc;    /* the default alloc is fine */
                    174:        nmp->nullm_vnodeop_p = null_vnodeop_p;
                    175:        simple_lock_init(&nmp->nullm_hashlock);
1.28      ad        176:        nmp->nullm_node_hashtbl = hashinit(NNULLNODECACHE, HASH_LIST, M_CACHE,
                    177:            M_WAITOK, &nmp->nullm_node_hash);
1.1       mycroft   178:
                    179:        /*
1.24      wrstuden  180:         * Fix up null node for root vnode
1.1       mycroft   181:         */
1.24      wrstuden  182:        error = layer_node_create(mp, lowerrootvp, &vp);
1.1       mycroft   183:        /*
1.24      wrstuden  184:         * Make sure the fixup worked
1.1       mycroft   185:         */
                    186:        if (error) {
1.24      wrstuden  187:                vput(lowerrootvp);
                    188:                free(nmp, M_UFSMNT);    /* XXX */
1.1       mycroft   189:                return (error);
                    190:        }
1.21      wrstuden  191:        /*
1.24      wrstuden  192:         * Unlock the node
1.21      wrstuden  193:         */
                    194:        VOP_UNLOCK(vp, 0);
1.1       mycroft   195:
                    196:        /*
                    197:         * Keep a held reference to the root vnode.
                    198:         * It is vrele'd in nullfs_unmount.
                    199:         */
1.24      wrstuden  200:        vp->v_flag |= VROOT;
                    201:        nmp->nullm_rootvp = vp;
1.1       mycroft   202:
                    203:        (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
1.20      perry     204:        memset(mp->mnt_stat.f_mntonname + size, 0, MNAMELEN - size);
1.24      wrstuden  205:        (void) copyinstr(args.la.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
1.1       mycroft   206:            &size);
1.20      perry     207:        memset(mp->mnt_stat.f_mntfromname + size, 0, MNAMELEN - size);
1.1       mycroft   208: #ifdef NULLFS_DIAGNOSTIC
1.13      christos  209:        printf("nullfs_mount: lower %s, alias at %s\n",
1.12      christos  210:            mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
1.1       mycroft   211: #endif
                    212:        return (0);
                    213: }
                    214:
                    215: /*
                    216:  * Free reference to null layer
                    217:  */
                    218: int
                    219: nullfs_unmount(mp, mntflags, p)
                    220:        struct mount *mp;
                    221:        int mntflags;
                    222:        struct proc *p;
                    223: {
1.24      wrstuden  224:        struct vnode *null_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
1.1       mycroft   225:        int error;
                    226:        int flags = 0;
                    227:
                    228: #ifdef NULLFS_DIAGNOSTIC
1.16      christos  229:        printf("nullfs_unmount(mp = %p)\n", mp);
1.1       mycroft   230: #endif
                    231:
1.19      fvdl      232:        if (mntflags & MNT_FORCE)
1.1       mycroft   233:                flags |= FORCECLOSE;
                    234:
                    235:        /*
                    236:         * Clear out buffer cache.  I don't think we
                    237:         * ever get anything cached at this level at the
                    238:         * moment, but who knows...
                    239:         */
                    240: #if 0
                    241:        mntflushbuf(mp, 0);
                    242:        if (mntinvalbuf(mp, 1))
                    243:                return (EBUSY);
                    244: #endif
1.24      wrstuden  245:        if (null_rootvp->v_usecount > 1)
1.1       mycroft   246:                return (EBUSY);
1.24      wrstuden  247:        if ((error = vflush(mp, null_rootvp, flags)) != 0)
1.1       mycroft   248:                return (error);
                    249:
                    250: #ifdef NULLFS_DIAGNOSTIC
1.24      wrstuden  251:        vprint("alias root of lower", null_rootvp);
1.1       mycroft   252: #endif
                    253:        /*
                    254:         * Release reference on underlying root vnode
                    255:         */
1.24      wrstuden  256:        vrele(null_rootvp);
1.1       mycroft   257:        /*
                    258:         * And blow it away for future re-use
                    259:         */
1.24      wrstuden  260:        vgone(null_rootvp);
1.1       mycroft   261:        /*
                    262:         * Finally, throw away the null_mount structure
                    263:         */
                    264:        free(mp->mnt_data, M_UFSMNT);   /* XXX */
                    265:        mp->mnt_data = 0;
                    266:        return 0;
                    267: }
                    268:
1.29      jdolecek  269: extern const struct vnodeopv_desc null_vnodeop_opv_desc;
1.18      thorpej   270:
1.29      jdolecek  271: const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = {
1.19      fvdl      272:        &null_vnodeop_opv_desc,
1.18      thorpej   273:        NULL,
                    274: };
                    275:
1.17      thorpej   276: struct vfsops nullfs_vfsops = {
1.1       mycroft   277:        MOUNT_NULL,
                    278:        nullfs_mount,
1.24      wrstuden  279:        layerfs_start,
1.1       mycroft   280:        nullfs_unmount,
1.24      wrstuden  281:        layerfs_root,
                    282:        layerfs_quotactl,
                    283:        layerfs_statfs,
                    284:        layerfs_sync,
                    285:        layerfs_vget,
                    286:        layerfs_fhtovp,
                    287:        layerfs_vptofh,
                    288:        layerfs_init,
1.26      jdolecek  289:        layerfs_done,
1.24      wrstuden  290:        layerfs_sysctl,
1.18      thorpej   291:        NULL,                           /* vfs_mountroot */
1.24      wrstuden  292:        layerfs_checkexp,
1.18      thorpej   293:        nullfs_vnodeopv_descs,
1.1       mycroft   294: };

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