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Annotation of src/sys/miscfs/overlay/overlay_vfsops.c, Revision 1.7.4.1

1.7.4.1 ! fvdl        1: /*     $NetBSD: overlay_vfsops.c,v 1.8 2001/09/15 16:12:59 chs Exp $   */
1.1       wrstuden    2:
                      3: /*
                      4:  * Copyright (c) 1999, 2000 National Aeronautics & Space Administration
                      5:  * All rights reserved.
                      6:  *
                      7:  * This software was written by William Studenmund of the
1.7       wiz         8:  * Numerical Aerospace Simulation Facility, NASA Ames Research Center.
1.1       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.
1.2       soren      18:  * 3. Neither the name of the National Aeronautics & Space Administration
1.1       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: /*
                     36:  * Copyright (c) 1992, 1993, 1995
                     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
                     72:  *     @(#)null_vfsops.c       8.7 (Berkeley) 5/14/95
                     73:  */
                     74:
                     75: /*
1.7       wiz        76:  * Overlay Layer
                     77:  * (See overlay_vnops.c for a description of what this does.)
1.1       wrstuden   78:  */
                     79:
                     80: #include <sys/param.h>
                     81: #include <sys/systm.h>
                     82: #include <sys/time.h>
                     83: #include <sys/proc.h>
                     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/overlay/overlay.h>
                     90: #include <miscfs/genfs/layer_extern.h>
                     91:
                     92: int    ov_mount __P((struct mount *, const char *, void *,
                     93:                          struct nameidata *, struct proc *));
                     94: int    ov_unmount __P((struct mount *, int, struct proc *));
                     95:
                     96: #define        NOVERLAYNODECACHE       16
                     97:
                     98: /*
                     99:  * Mount overlay layer
                    100:  */
                    101: int
                    102: ov_mount(mp, path, data, ndp, p)
                    103:        struct mount *mp;
                    104:        const char *path;
                    105:        void *data;
                    106:        struct nameidata *ndp;
                    107:        struct proc *p;
                    108: {
                    109:        int error = 0;
                    110:        struct overlay_args args;
                    111:        struct vnode *lowerrootvp, *vp;
                    112:        struct overlay_mount *nmp;
                    113:        struct layer_mount *lmp;
                    114:        size_t size;
                    115:
                    116: #ifdef OVERLAYFS_DIAGNOSTIC
                    117:        printf("ov_mount(mp = %p)\n", mp);
                    118: #endif
                    119:
                    120:        /*
                    121:         * Get argument
                    122:         */
                    123:        error = copyin(data, (caddr_t)&args, sizeof(struct overlay_args));
                    124:        if (error)
                    125:                return (error);
                    126:
                    127:        /*
                    128:         * Update only does export updating.
                    129:         */
                    130:        if (mp->mnt_flag & MNT_UPDATE) {
                    131:                lmp = MOUNTTOLAYERMOUNT(mp);
                    132:                if (args.ova_target == 0)
                    133:                        return (vfs_export(mp, &lmp->layerm_export,
                    134:                                        &args.la.export));
                    135:                else
                    136:                        return (EOPNOTSUPP);
                    137:        }
                    138:
                    139:        /*
                    140:         * Find lower node
                    141:         */
                    142:        lowerrootvp = mp->mnt_vnodecovered;
                    143:        if ((error = vget(lowerrootvp, LK_EXCLUSIVE | LK_RETRY)))
                    144:                return (error);
                    145:
                    146:        /*
                    147:         * First cut at fixing up upper mount point
                    148:         */
                    149:        nmp = (struct overlay_mount *) malloc(sizeof(struct overlay_mount),
                    150:                                M_UFSMNT, M_WAITOK);    /* XXX */
                    151:        memset((caddr_t)nmp, 0, sizeof(struct overlay_mount));
                    152:
                    153:        mp->mnt_data = (qaddr_t) nmp;
                    154:        nmp->ovm_vfs = lowerrootvp->v_mount;
                    155:        if (nmp->ovm_vfs->mnt_flag & MNT_LOCAL)
                    156:                mp->mnt_flag |= MNT_LOCAL;
                    157:
                    158:        /*
                    159:         * Make sure that the mount point is sufficiently initialized
                    160:         * that the node create call will work.
                    161:         */
1.4       assar     162:        vfs_getnewfsid(mp);
1.1       wrstuden  163:
                    164:        nmp->ovm_size = sizeof (struct overlay_node);
                    165:        nmp->ovm_tag = VT_OVERLAY;
                    166:        nmp->ovm_bypass = layer_bypass;
                    167:        nmp->ovm_alloc = layer_node_alloc;      /* the default alloc is fine */
                    168:        nmp->ovm_vnodeop_p = overlay_vnodeop_p;
                    169:        simple_lock_init(&nmp->ovm_hashlock);
1.5       ad        170:        nmp->ovm_node_hashtbl = hashinit(NOVERLAYNODECACHE, HASH_LIST, M_CACHE,
                    171:            M_WAITOK, &nmp->ovm_node_hash);
1.1       wrstuden  172:
                    173:        /*
                    174:         * Fix up overlay node for root vnode
                    175:         */
                    176:        error = layer_node_create(mp, lowerrootvp, &vp);
                    177:        /*
                    178:         * Make sure the fixup worked
                    179:         */
                    180:        if (error) {
                    181:                vput(lowerrootvp);
                    182:                free(nmp, M_UFSMNT);    /* XXX */
                    183:                return (error);
                    184:        }
                    185:        /*
                    186:         * Unlock the node
                    187:         */
                    188:        VOP_UNLOCK(vp, 0);
                    189:
                    190:        /*
                    191:         * Keep a held reference to the root vnode.
                    192:         * It is vrele'd in ov_unmount.
                    193:         */
                    194:        vp->v_flag |= VROOT;
                    195:        nmp->ovm_rootvp = vp;
                    196:
                    197:        (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
                    198:        memset(mp->mnt_stat.f_mntonname + size, 0, MNAMELEN - size);
                    199:        (void) copyinstr(args.la.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
                    200:            &size);
                    201:        memset(mp->mnt_stat.f_mntfromname + size, 0, MNAMELEN - size);
                    202: #ifdef OVERLAYFS_DIAGNOSTIC
                    203:        printf("ov_mount: lower %s, alias at %s\n",
                    204:            mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
                    205: #endif
                    206:        return (0);
                    207: }
                    208:
                    209: /*
                    210:  * Free reference to overlay layer
                    211:  */
                    212: int
                    213: ov_unmount(mp, mntflags, p)
                    214:        struct mount *mp;
                    215:        int mntflags;
                    216:        struct proc *p;
                    217: {
                    218:        struct vnode *overlay_rootvp = MOUNTTOOVERLAYMOUNT(mp)->ovm_rootvp;
                    219:        int error;
                    220:        int flags = 0;
                    221:
                    222: #ifdef OVERLAYFS_DIAGNOSTIC
                    223:        printf("ov_unmount(mp = %p)\n", mp);
                    224: #endif
                    225:
                    226:        if (mntflags & MNT_FORCE)
                    227:                flags |= FORCECLOSE;
                    228:
                    229:        /*
                    230:         * Clear out buffer cache.  I don't think we
                    231:         * ever get anything cached at this level at the
                    232:         * moment, but who knows...
                    233:         */
                    234: #if 0
                    235:        mntflushbuf(mp, 0);
                    236:        if (mntinvalbuf(mp, 1))
                    237:                return (EBUSY);
                    238: #endif
                    239:        if (overlay_rootvp->v_usecount > 1)
                    240:                return (EBUSY);
                    241:        if ((error = vflush(mp, overlay_rootvp, flags)) != 0)
                    242:                return (error);
                    243:
                    244: #ifdef OVERLAYFS_DIAGNOSTIC
                    245:        vprint("alias root of lower", overlay_rootvp);
                    246: #endif
                    247:        /*
                    248:         * Release reference on underlying root vnode
                    249:         */
                    250:        vrele(overlay_rootvp);
                    251:        /*
                    252:         * And blow it away for future re-use
                    253:         */
                    254:        vgone(overlay_rootvp);
                    255:        /*
                    256:         * Finally, throw away the overlay_mount structure
                    257:         */
                    258:        free(mp->mnt_data, M_UFSMNT);   /* XXX */
                    259:        mp->mnt_data = 0;
                    260:        return 0;
                    261: }
                    262:
1.6       jdolecek  263: extern const struct vnodeopv_desc overlay_vnodeop_opv_desc;
1.1       wrstuden  264:
1.6       jdolecek  265: const struct vnodeopv_desc * const ov_vnodeopv_descs[] = {
1.1       wrstuden  266:        &overlay_vnodeop_opv_desc,
                    267:        NULL,
                    268: };
                    269:
                    270: struct vfsops overlay_vfsops = {
                    271:        MOUNT_OVERLAY,
                    272:        ov_mount,
                    273:        layerfs_start,
                    274:        ov_unmount,
                    275:        layerfs_root,
                    276:        layerfs_quotactl,
                    277:        layerfs_statfs,
                    278:        layerfs_sync,
                    279:        layerfs_vget,
                    280:        layerfs_fhtovp,
                    281:        layerfs_vptofh,
                    282:        layerfs_init,
1.7.4.1 ! fvdl      283:        NULL,
1.3       jdolecek  284:        layerfs_done,
1.1       wrstuden  285:        layerfs_sysctl,
                    286:        NULL,                           /* vfs_mountroot */
                    287:        layerfs_checkexp,
                    288:        ov_vnodeopv_descs,
                    289: };

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