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Annotation of XNU/bsd/miscfs/nullfs/null_vfsops.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * The contents of this file constitute Original Code as defined in and
        !             7:  * are subject to the Apple Public Source License Version 1.1 (the
        !             8:  * "License").  You may not use this file except in compliance with the
        !             9:  * License.  Please obtain a copy of the License at
        !            10:  * http://www.apple.com/publicsource and read it before using this file.
        !            11:  * 
        !            12:  * This Original Code and all software distributed under the License are
        !            13:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            14:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            15:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            16:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            17:  * License for the specific language governing rights and limitations
        !            18:  * under the License.
        !            19:  * 
        !            20:  * @APPLE_LICENSE_HEADER_END@
        !            21:  */
        !            22: /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
        !            23: /*
        !            24:  * Copyright (c) 1992, 1993
        !            25:  *     The Regents of the University of California.  All rights reserved.
        !            26:  *
        !            27:  * This code is derived from software donated to Berkeley by
        !            28:  * Jan-Simon Pendry.
        !            29:  *
        !            30:  * Redistribution and use in source and binary forms, with or without
        !            31:  * modification, are permitted provided that the following conditions
        !            32:  * are met:
        !            33:  * 1. Redistributions of source code must retain the above copyright
        !            34:  *    notice, this list of conditions and the following disclaimer.
        !            35:  * 2. Redistributions in binary form must reproduce the above copyright
        !            36:  *    notice, this list of conditions and the following disclaimer in the
        !            37:  *    documentation and/or other materials provided with the distribution.
        !            38:  * 3. All advertising materials mentioning features or use of this software
        !            39:  *    must display the following acknowledgement:
        !            40:  *     This product includes software developed by the University of
        !            41:  *     California, Berkeley and its contributors.
        !            42:  * 4. Neither the name of the University nor the names of its contributors
        !            43:  *    may be used to endorse or promote products derived from this software
        !            44:  *    without specific prior written permission.
        !            45:  *
        !            46:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            47:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            48:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            49:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            50:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            51:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            52:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            53:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            54:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            55:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            56:  * SUCH DAMAGE.
        !            57:  *
        !            58:  *     @(#)null_vfsops.c       8.7 (Berkeley) 5/14/95
        !            59:  *
        !            60:  * @(#)lofs_vfsops.c   1.2 (Berkeley) 6/18/92
        !            61:  */
        !            62: 
        !            63: /*
        !            64:  * Null Layer
        !            65:  * (See null_vnops.c for a description of what this does.)
        !            66:  */
        !            67: 
        !            68: #include <sys/param.h>
        !            69: #include <sys/systm.h>
        !            70: #include <sys/proc.h>
        !            71: #include <sys/time.h>
        !            72: #include <sys/types.h>
        !            73: #include <sys/vnode.h>
        !            74: #include <sys/mount.h>
        !            75: #include <sys/namei.h>
        !            76: #include <sys/malloc.h>
        !            77: #include <miscfs/nullfs/null.h>
        !            78: 
        !            79: /*
        !            80:  * Mount null layer
        !            81:  */
        !            82: int
        !            83: nullfs_mount(mp, path, data, ndp, p)
        !            84:        struct mount *mp;
        !            85:        char *path;
        !            86:        caddr_t data;
        !            87:        struct nameidata *ndp;
        !            88:        struct proc *p;
        !            89: {
        !            90:        int error = 0;
        !            91:        struct null_args args;
        !            92:        struct vnode *lowerrootvp, *vp;
        !            93:        struct vnode *nullm_rootvp;
        !            94:        struct null_mount *xmp;
        !            95:        u_int size;
        !            96: 
        !            97: #ifdef NULLFS_DIAGNOSTIC
        !            98:        printf("nullfs_mount(mp = %x)\n", mp);
        !            99: #endif
        !           100: 
        !           101:        /*
        !           102:         * Update is a no-op
        !           103:         */
        !           104:        if (mp->mnt_flag & MNT_UPDATE) {
        !           105:                return (EOPNOTSUPP);
        !           106:                /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/
        !           107:        }
        !           108: 
        !           109:        /*
        !           110:         * Get argument
        !           111:         */
        !           112:        if (error = copyin(data, (caddr_t)&args, sizeof(struct null_args)))
        !           113:                return (error);
        !           114: 
        !           115:        /*
        !           116:         * Find lower node
        !           117:         */
        !           118:        NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
        !           119:                UIO_USERSPACE, args.target, p);
        !           120:        if (error = namei(ndp))
        !           121:                return (error);
        !           122: 
        !           123:        /*
        !           124:         * Sanity check on lower vnode
        !           125:         */
        !           126:        lowerrootvp = ndp->ni_vp;
        !           127: 
        !           128:        vrele(ndp->ni_dvp);
        !           129:        ndp->ni_dvp = NULL;
        !           130: 
        !           131:        xmp = (struct null_mount *) _MALLOC(sizeof(struct null_mount),
        !           132:                                M_UFSMNT, M_WAITOK);    /* XXX */
        !           133: 
        !           134:        /*
        !           135:         * Save reference to underlying FS
        !           136:         */
        !           137:        xmp->nullm_vfs = lowerrootvp->v_mount;
        !           138: 
        !           139:        /*
        !           140:         * Save reference.  Each mount also holds
        !           141:         * a reference on the root vnode.
        !           142:         */
        !           143:        error = null_node_create(mp, lowerrootvp, &vp);
        !           144:        /*
        !           145:         * Unlock the node (either the lower or the alias)
        !           146:         */
        !           147:        VOP_UNLOCK(vp, 0, p);
        !           148:        /*
        !           149:         * Make sure the node alias worked
        !           150:         */
        !           151:        if (error) {
        !           152:                vrele(lowerrootvp);
        !           153:                FREE(xmp, M_UFSMNT);    /* XXX */
        !           154:                return (error);
        !           155:        }
        !           156: 
        !           157:        /*
        !           158:         * Keep a held reference to the root vnode.
        !           159:         * It is vrele'd in nullfs_unmount.
        !           160:         */
        !           161:        nullm_rootvp = vp;
        !           162:        nullm_rootvp->v_flag |= VROOT;
        !           163:        xmp->nullm_rootvp = nullm_rootvp;
        !           164:        if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
        !           165:                mp->mnt_flag |= MNT_LOCAL;
        !           166:        mp->mnt_data = (qaddr_t) xmp;
        !           167:        vfs_getnewfsid(mp);
        !           168: 
        !           169:        (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
        !           170:        bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
        !           171:        (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 
        !           172:            &size);
        !           173:        bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
        !           174: #ifdef NULLFS_DIAGNOSTIC
        !           175:        printf("nullfs_mount: lower %s, alias at %s\n",
        !           176:                mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
        !           177: #endif
        !           178:        return (0);
        !           179: }
        !           180: 
        !           181: /*
        !           182:  * VFS start.  Nothing needed here - the start routine
        !           183:  * on the underlying filesystem will have been called
        !           184:  * when that filesystem was mounted.
        !           185:  */
        !           186: int
        !           187: nullfs_start(mp, flags, p)
        !           188:        struct mount *mp;
        !           189:        int flags;
        !           190:        struct proc *p;
        !           191: {
        !           192:        return (0);
        !           193:        /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */
        !           194: }
        !           195: 
        !           196: /*
        !           197:  * Free reference to null layer
        !           198:  */
        !           199: int
        !           200: nullfs_unmount(mp, mntflags, p)
        !           201:        struct mount *mp;
        !           202:        int mntflags;
        !           203:        struct proc *p;
        !           204: {
        !           205:        struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
        !           206:        int error;
        !           207:        int flags = 0;
        !           208: 
        !           209: #ifdef NULLFS_DIAGNOSTIC
        !           210:        printf("nullfs_unmount(mp = %x)\n", mp);
        !           211: #endif
        !           212: 
        !           213:        if (mntflags & MNT_FORCE)
        !           214:                flags |= FORCECLOSE;
        !           215: 
        !           216:        /*
        !           217:         * Clear out buffer cache.  I don't think we
        !           218:         * ever get anything cached at this level at the
        !           219:         * moment, but who knows...
        !           220:         */
        !           221: #if 0
        !           222:        mntflushbuf(mp, 0); 
        !           223:        if (mntinvalbuf(mp, 1))
        !           224:                return (EBUSY);
        !           225: #endif
        !           226:        if (nullm_rootvp->v_usecount > 1)
        !           227:                return (EBUSY);
        !           228:        if (error = vflush(mp, nullm_rootvp, flags))
        !           229:                return (error);
        !           230: 
        !           231: #ifdef NULLFS_DIAGNOSTIC
        !           232:        vprint("alias root of lower", nullm_rootvp);
        !           233: #endif  
        !           234:        /*
        !           235:         * Release reference on underlying root vnode
        !           236:         */
        !           237:        vrele(nullm_rootvp);
        !           238:        /*
        !           239:         * And blow it away for future re-use
        !           240:         */
        !           241:        vgone(nullm_rootvp);
        !           242:        /*
        !           243:         * Finally, throw away the null_mount structure
        !           244:         */
        !           245:        FREE(mp->mnt_data, M_UFSMNT);   /* XXX */
        !           246:        mp->mnt_data = 0;
        !           247:        return 0;
        !           248: }
        !           249: 
        !           250: int
        !           251: nullfs_root(mp, vpp)
        !           252:        struct mount *mp;
        !           253:        struct vnode **vpp;
        !           254: {
        !           255:        struct proc *p = curproc;       /* XXX */
        !           256:        struct vnode *vp;
        !           257: 
        !           258: #ifdef NULLFS_DIAGNOSTIC
        !           259:        printf("nullfs_root(mp = %x, vp = %x->%x)\n", mp,
        !           260:                        MOUNTTONULLMOUNT(mp)->nullm_rootvp,
        !           261:                        NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
        !           262:                        );
        !           263: #endif
        !           264: 
        !           265:        /*
        !           266:         * Return locked reference to root.
        !           267:         */
        !           268:        vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
        !           269:        VREF(vp);
        !           270:        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
        !           271:        *vpp = vp;
        !           272:        return 0;
        !           273: }
        !           274: 
        !           275: int
        !           276: nullfs_quotactl(mp, cmd, uid, arg, p)
        !           277:        struct mount *mp;
        !           278:        int cmd;
        !           279:        uid_t uid;
        !           280:        caddr_t arg;
        !           281:        struct proc *p;
        !           282: {
        !           283:        return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p);
        !           284: }
        !           285: 
        !           286: int
        !           287: nullfs_statfs(mp, sbp, p)
        !           288:        struct mount *mp;
        !           289:        struct statfs *sbp;
        !           290:        struct proc *p;
        !           291: {
        !           292:        int error;
        !           293:        struct statfs mstat;
        !           294: 
        !           295: #ifdef NULLFS_DIAGNOSTIC
        !           296:        printf("nullfs_statfs(mp = %x, vp = %x->%x)\n", mp,
        !           297:                        MOUNTTONULLMOUNT(mp)->nullm_rootvp,
        !           298:                        NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
        !           299:                        );
        !           300: #endif
        !           301: 
        !           302:        bzero(&mstat, sizeof(mstat));
        !           303: 
        !           304:        error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p);
        !           305:        if (error)
        !           306:                return (error);
        !           307: 
        !           308:        /* now copy across the "interesting" information and fake the rest */
        !           309:        sbp->f_type = mstat.f_type;
        !           310:        sbp->f_flags = mstat.f_flags;
        !           311:        sbp->f_bsize = mstat.f_bsize;
        !           312:        sbp->f_iosize = mstat.f_iosize;
        !           313:        sbp->f_blocks = mstat.f_blocks;
        !           314:        sbp->f_bfree = mstat.f_bfree;
        !           315:        sbp->f_bavail = mstat.f_bavail;
        !           316:        sbp->f_files = mstat.f_files;
        !           317:        sbp->f_ffree = mstat.f_ffree;
        !           318:        if (sbp != &mp->mnt_stat) {
        !           319:                bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
        !           320:                bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
        !           321:                bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
        !           322:        }
        !           323:        return (0);
        !           324: }
        !           325: 
        !           326: int
        !           327: nullfs_sync(mp, waitfor, cred, p)
        !           328:        struct mount *mp;
        !           329:        int waitfor;
        !           330:        struct ucred *cred;
        !           331:        struct proc *p;
        !           332: {
        !           333:        /*
        !           334:         * XXX - Assumes no data cached at null layer.
        !           335:         */
        !           336:        return (0);
        !           337: }
        !           338: 
        !           339: int
        !           340: nullfs_vget(mp, ino, vpp)
        !           341:        struct mount *mp;
        !           342:        ino_t ino;
        !           343:        struct vnode **vpp;
        !           344: {
        !           345:        
        !           346:        return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
        !           347: }
        !           348: 
        !           349: int
        !           350: nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp)
        !           351:        struct mount *mp;
        !           352:        struct fid *fidp;
        !           353:        struct mbuf *nam;
        !           354:        struct vnode **vpp;
        !           355:        int *exflagsp;
        !           356:        struct ucred**credanonp;
        !           357: {
        !           358: 
        !           359:        return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, nam, vpp, exflagsp,credanonp);
        !           360: }
        !           361: 
        !           362: int
        !           363: nullfs_vptofh(vp, fhp)
        !           364:        struct vnode *vp;
        !           365:        struct fid *fhp;
        !           366: {
        !           367:        return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
        !           368: }
        !           369: 
        !           370: int nullfs_init __P((struct vfsconf *));
        !           371: 
        !           372: #define nullfs_sysctl ((int (*) __P((int *, u_int, void *, size_t *, void *, \
        !           373:            size_t, struct proc *)))eopnotsupp)
        !           374: 
        !           375: struct vfsops null_vfsops = {
        !           376:        nullfs_mount,
        !           377:        nullfs_start,
        !           378:        nullfs_unmount,
        !           379:        nullfs_root,
        !           380:        nullfs_quotactl,
        !           381:        nullfs_statfs,
        !           382:        nullfs_sync,
        !           383:        nullfs_vget,
        !           384:        nullfs_fhtovp,
        !           385:        nullfs_vptofh,
        !           386:        nullfs_init,
        !           387:        nullfs_sysctl,
        !           388: };

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