Annotation of src/sys/miscfs/nullfs/null_vfsops.c, Revision 1.1
1.1 ! mycroft 1: /*
! 2: * Copyright (c) 1992, 1993
! 3: * The Regents of the University of California. All rights reserved.
! 4: *
! 5: * This code is derived from software donated to Berkeley by
! 6: * Jan-Simon Pendry.
! 7: *
! 8: * Redistribution and use in source and binary forms, with or without
! 9: * modification, are permitted provided that the following conditions
! 10: * are met:
! 11: * 1. Redistributions of source code must retain the above copyright
! 12: * notice, this list of conditions and the following disclaimer.
! 13: * 2. Redistributions in binary form must reproduce the above copyright
! 14: * notice, this list of conditions and the following disclaimer in the
! 15: * documentation and/or other materials provided with the distribution.
! 16: * 3. All advertising materials mentioning features or use of this software
! 17: * must display the following acknowledgement:
! 18: * This product includes software developed by the University of
! 19: * California, Berkeley and its contributors.
! 20: * 4. Neither the name of the University nor the names of its contributors
! 21: * may be used to endorse or promote products derived from this software
! 22: * without specific prior written permission.
! 23: *
! 24: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 25: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 26: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 27: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 28: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 29: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 30: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 31: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 32: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 33: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 34: * SUCH DAMAGE.
! 35: *
! 36: * from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp
! 37: * from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
! 38: * from: @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94
! 39: * $Id: $
! 40: */
! 41:
! 42: /*
! 43: * Null Layer
! 44: * (See null_vnops.c for a description of what this does.)
! 45: */
! 46:
! 47: #include <sys/param.h>
! 48: #include <sys/systm.h>
! 49: #include <sys/time.h>
! 50: #include <sys/types.h>
! 51: #include <sys/vnode.h>
! 52: #include <sys/mount.h>
! 53: #include <sys/namei.h>
! 54: #include <sys/malloc.h>
! 55: #include <miscfs/nullfs/null.h>
! 56:
! 57: /*
! 58: * Mount null layer
! 59: */
! 60: int
! 61: nullfs_mount(mp, path, data, ndp, p)
! 62: struct mount *mp;
! 63: char *path;
! 64: caddr_t data;
! 65: struct nameidata *ndp;
! 66: struct proc *p;
! 67: {
! 68: int error = 0;
! 69: struct null_args args;
! 70: struct vnode *lowerrootvp, *vp;
! 71: struct vnode *nullm_rootvp;
! 72: struct null_mount *xmp;
! 73: u_int size;
! 74:
! 75: #ifdef NULLFS_DIAGNOSTIC
! 76: printf("nullfs_mount(mp = %x)\n", mp);
! 77: #endif
! 78:
! 79: /*
! 80: * Update is a no-op
! 81: */
! 82: if (mp->mnt_flag & MNT_UPDATE) {
! 83: return (EOPNOTSUPP);
! 84: /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/
! 85: }
! 86:
! 87: /*
! 88: * Get argument
! 89: */
! 90: if (error = copyin(data, (caddr_t)&args, sizeof(struct null_args)))
! 91: return (error);
! 92:
! 93: /*
! 94: * Find lower node
! 95: */
! 96: NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
! 97: UIO_USERSPACE, args.target, p);
! 98: if (error = namei(ndp))
! 99: return (error);
! 100:
! 101: /*
! 102: * Sanity check on lower vnode
! 103: */
! 104: lowerrootvp = ndp->ni_vp;
! 105:
! 106: vrele(ndp->ni_dvp);
! 107: ndp->ni_dvp = NULL;
! 108:
! 109: xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
! 110: M_UFSMNT, M_WAITOK); /* XXX */
! 111:
! 112: /*
! 113: * Save reference to underlying FS
! 114: */
! 115: xmp->nullm_vfs = lowerrootvp->v_mount;
! 116:
! 117: /*
! 118: * Save reference. Each mount also holds
! 119: * a reference on the root vnode.
! 120: */
! 121: error = null_node_create(mp, lowerrootvp, &vp);
! 122: /*
! 123: * Unlock the node (either the lower or the alias)
! 124: */
! 125: VOP_UNLOCK(vp);
! 126: /*
! 127: * Make sure the node alias worked
! 128: */
! 129: if (error) {
! 130: vrele(lowerrootvp);
! 131: free(xmp, M_UFSMNT); /* XXX */
! 132: return (error);
! 133: }
! 134:
! 135: /*
! 136: * Keep a held reference to the root vnode.
! 137: * It is vrele'd in nullfs_unmount.
! 138: */
! 139: nullm_rootvp = vp;
! 140: nullm_rootvp->v_flag |= VROOT;
! 141: xmp->nullm_rootvp = nullm_rootvp;
! 142: if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
! 143: mp->mnt_flag |= MNT_LOCAL;
! 144: mp->mnt_data = (qaddr_t) xmp;
! 145: getnewfsid(mp, makefstype(MOUNT_LOFS));
! 146:
! 147: (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
! 148: bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
! 149: (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
! 150: &size);
! 151: bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
! 152: #ifdef NULLFS_DIAGNOSTIC
! 153: printf("nullfs_mount: lower %s, alias at %s\n",
! 154: mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
! 155: #endif
! 156: return (0);
! 157: }
! 158:
! 159: /*
! 160: * VFS start. Nothing needed here - the start routine
! 161: * on the underlying filesystem will have been called
! 162: * when that filesystem was mounted.
! 163: */
! 164: int
! 165: nullfs_start(mp, flags, p)
! 166: struct mount *mp;
! 167: int flags;
! 168: struct proc *p;
! 169: {
! 170:
! 171: return (0);
! 172: /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */
! 173: }
! 174:
! 175: /*
! 176: * Free reference to null layer
! 177: */
! 178: int
! 179: nullfs_unmount(mp, mntflags, p)
! 180: struct mount *mp;
! 181: int mntflags;
! 182: struct proc *p;
! 183: {
! 184: struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
! 185: int error;
! 186: int flags = 0;
! 187: extern int doforce;
! 188:
! 189: #ifdef NULLFS_DIAGNOSTIC
! 190: printf("nullfs_unmount(mp = %x)\n", mp);
! 191: #endif
! 192:
! 193: if (mntflags & MNT_FORCE) {
! 194: /* lofs can never be rootfs so don't check for it */
! 195: if (!doforce)
! 196: return (EINVAL);
! 197: flags |= FORCECLOSE;
! 198: }
! 199:
! 200: /*
! 201: * Clear out buffer cache. I don't think we
! 202: * ever get anything cached at this level at the
! 203: * moment, but who knows...
! 204: */
! 205: #if 0
! 206: mntflushbuf(mp, 0);
! 207: if (mntinvalbuf(mp, 1))
! 208: return (EBUSY);
! 209: #endif
! 210: if (nullm_rootvp->v_usecount > 1)
! 211: return (EBUSY);
! 212: if (error = vflush(mp, nullm_rootvp, flags))
! 213: return (error);
! 214:
! 215: #ifdef NULLFS_DIAGNOSTIC
! 216: vprint("alias root of lower", nullm_rootvp);
! 217: #endif
! 218: /*
! 219: * Release reference on underlying root vnode
! 220: */
! 221: vrele(nullm_rootvp);
! 222: /*
! 223: * And blow it away for future re-use
! 224: */
! 225: vgone(nullm_rootvp);
! 226: /*
! 227: * Finally, throw away the null_mount structure
! 228: */
! 229: free(mp->mnt_data, M_UFSMNT); /* XXX */
! 230: mp->mnt_data = 0;
! 231: return 0;
! 232: }
! 233:
! 234: int
! 235: nullfs_root(mp, vpp)
! 236: struct mount *mp;
! 237: struct vnode **vpp;
! 238: {
! 239: struct vnode *vp;
! 240:
! 241: #ifdef NULLFS_DIAGNOSTIC
! 242: printf("nullfs_root(mp = %x, vp = %x->%x)\n", mp,
! 243: MOUNTTONULLMOUNT(mp)->nullm_rootvp,
! 244: NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
! 245: );
! 246: #endif
! 247:
! 248: /*
! 249: * Return locked reference to root.
! 250: */
! 251: vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
! 252: VREF(vp);
! 253: VOP_LOCK(vp);
! 254: *vpp = vp;
! 255: return 0;
! 256: }
! 257:
! 258: int
! 259: nullfs_quotactl(mp, cmd, uid, arg, p)
! 260: struct mount *mp;
! 261: int cmd;
! 262: uid_t uid;
! 263: caddr_t arg;
! 264: struct proc *p;
! 265: {
! 266:
! 267: return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p);
! 268: }
! 269:
! 270: int
! 271: nullfs_statfs(mp, sbp, p)
! 272: struct mount *mp;
! 273: struct statfs *sbp;
! 274: struct proc *p;
! 275: {
! 276: int error;
! 277: struct statfs mstat;
! 278:
! 279: #ifdef NULLFS_DIAGNOSTIC
! 280: printf("nullfs_statfs(mp = %x, vp = %x->%x)\n", mp,
! 281: MOUNTTONULLMOUNT(mp)->nullm_rootvp,
! 282: NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
! 283: );
! 284: #endif
! 285:
! 286: bzero(&mstat, sizeof(mstat));
! 287:
! 288: error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p);
! 289: if (error)
! 290: return (error);
! 291:
! 292: /* now copy across the "interesting" information and fake the rest */
! 293: sbp->f_type = mstat.f_type;
! 294: sbp->f_flags = mstat.f_flags;
! 295: sbp->f_bsize = mstat.f_bsize;
! 296: sbp->f_iosize = mstat.f_iosize;
! 297: sbp->f_blocks = mstat.f_blocks;
! 298: sbp->f_bfree = mstat.f_bfree;
! 299: sbp->f_bavail = mstat.f_bavail;
! 300: sbp->f_files = mstat.f_files;
! 301: sbp->f_ffree = mstat.f_ffree;
! 302: if (sbp != &mp->mnt_stat) {
! 303: bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
! 304: bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
! 305: bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
! 306: }
! 307: strncpy(&sbp->f_fstypename[0], &mstat.f_fstypename[0], MFSNAMELEN);
! 308: sbp->f_fstypename[MFSNAMELEN] = '\0';
! 309: return (0);
! 310: }
! 311:
! 312: int
! 313: nullfs_sync(mp, waitfor, cred, p)
! 314: struct mount *mp;
! 315: int waitfor;
! 316: struct ucred *cred;
! 317: struct proc *p;
! 318: {
! 319:
! 320: /*
! 321: * XXX - Assumes no data cached at null layer.
! 322: */
! 323: return (0);
! 324: }
! 325:
! 326: int
! 327: nullfs_vget(mp, ino, vpp)
! 328: struct mount *mp;
! 329: ino_t ino;
! 330: struct vnode **vpp;
! 331: {
! 332:
! 333: return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
! 334: }
! 335:
! 336: int
! 337: nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp)
! 338: struct mount *mp;
! 339: struct fid *fidp;
! 340: struct mbuf *nam;
! 341: struct vnode **vpp;
! 342: int *exflagsp;
! 343: struct ucred**credanonp;
! 344: {
! 345:
! 346: return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, nam, vpp, exflagsp,credanonp);
! 347: }
! 348:
! 349: int
! 350: nullfs_vptofh(vp, fhp)
! 351: struct vnode *vp;
! 352: struct fid *fhp;
! 353: {
! 354:
! 355: return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
! 356: }
! 357:
! 358: int nullfs_init __P((void));
! 359:
! 360: struct vfsops null_vfsops = {
! 361: MOUNT_NULL,
! 362: nullfs_mount,
! 363: nullfs_start,
! 364: nullfs_unmount,
! 365: nullfs_root,
! 366: nullfs_quotactl,
! 367: nullfs_statfs,
! 368: nullfs_sync,
! 369: nullfs_vget,
! 370: nullfs_fhtovp,
! 371: nullfs_vptofh,
! 372: nullfs_init,
! 373: };
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