1 /* 2 * Copyright (c) 1989, 1990, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)mfs_vfsops.c 8.11 (Berkeley) 6/19/95 34 * $FreeBSD: src/sys/ufs/mfs/mfs_vfsops.c,v 1.81.2.3 2001/07/04 17:35:21 tegge Exp $ 35 * $DragonFly: src/sys/vfs/mfs/mfs_vfsops.c,v 1.41 2008/07/26 22:31:54 mneumann Exp $ 36 */ 37 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/conf.h> 42 #include <sys/device.h> 43 #include <sys/kernel.h> 44 #include <sys/proc.h> 45 #include <sys/buf.h> 46 #include <sys/mount.h> 47 #include <sys/signalvar.h> 48 #include <sys/signal2.h> 49 #include <sys/vnode.h> 50 #include <sys/malloc.h> 51 #include <sys/linker.h> 52 #include <sys/fcntl.h> 53 54 #include <vm/vm.h> 55 #include <vm/vm_object.h> 56 #include <vm/vm_page.h> 57 #include <vm/vm_pager.h> 58 #include <vm/vnode_pager.h> 59 60 #include <sys/buf2.h> 61 #include <sys/thread2.h> 62 63 #include <vfs/ufs/quota.h> 64 #include <vfs/ufs/inode.h> 65 #include <vfs/ufs/ufsmount.h> 66 #include <vfs/ufs/ufs_extern.h> 67 #include <vfs/ufs/fs.h> 68 #include <vfs/ufs/ffs_extern.h> 69 70 #include "mfsnode.h" 71 #include "mfs_extern.h" 72 73 MALLOC_DEFINE(M_MFSNODE, "MFS node", "MFS vnode private part"); 74 75 extern struct vop_ops *mfs_vnode_vops_p; 76 77 static int mfs_mount (struct mount *mp, 78 char *path, caddr_t data, struct ucred *td); 79 static int mfs_start (struct mount *mp, int flags); 80 static int mfs_statfs (struct mount *mp, struct statfs *sbp, 81 struct ucred *cred); 82 static int mfs_init (struct vfsconf *); 83 84 d_open_t mfsopen; 85 d_close_t mfsclose; 86 d_strategy_t mfsstrategy; 87 88 static struct dev_ops mfs_ops = { 89 { "MFS", -1, D_DISK }, 90 .d_open = mfsopen, 91 .d_close = mfsclose, 92 .d_read = physread, 93 .d_write = physwrite, 94 .d_strategy = mfsstrategy, 95 }; 96 97 /* 98 * mfs vfs operations. 99 */ 100 static struct vfsops mfs_vfsops = { 101 .vfs_mount = mfs_mount, 102 .vfs_start = mfs_start, 103 .vfs_unmount = ffs_unmount, 104 .vfs_root = ufs_root, 105 .vfs_quotactl = ufs_quotactl, 106 .vfs_statfs = mfs_statfs, 107 .vfs_sync = ffs_sync, 108 .vfs_vget = ffs_vget, 109 .vfs_fhtovp = ffs_fhtovp, 110 .vfs_checkexp = ufs_check_export, 111 .vfs_vptofh = ffs_vptofh, 112 .vfs_init = mfs_init 113 }; 114 115 VFS_SET(mfs_vfsops, mfs, 0); 116 117 /* 118 * We allow the underlying MFS block device to be opened and read. 119 */ 120 int 121 mfsopen(struct dev_open_args *ap) 122 { 123 cdev_t dev = ap->a_head.a_dev; 124 125 if (ap->a_oflags & FWRITE) 126 return(EROFS); 127 if (dev->si_drv1) 128 return(0); 129 return(ENXIO); 130 } 131 132 int 133 mfsclose(struct dev_close_args *ap) 134 { 135 return(0); 136 } 137 138 int 139 mfsstrategy(struct dev_strategy_args *ap) 140 { 141 cdev_t dev = ap->a_head.a_dev; 142 struct bio *bio = ap->a_bio; 143 struct buf *bp = bio->bio_buf; 144 off_t boff = bio->bio_offset; 145 off_t eoff = boff + bp->b_bcount; 146 struct mfsnode *mfsp; 147 148 if ((mfsp = dev->si_drv1) == NULL) { 149 bp->b_error = ENXIO; 150 goto error; 151 } 152 if (boff < 0) 153 goto bad; 154 if (eoff > mfsp->mfs_size) { 155 if (boff > mfsp->mfs_size || (bp->b_flags & B_BNOCLIP)) 156 goto bad; 157 /* 158 * Return EOF by completing the I/O with 0 bytes transfered. 159 * Set B_INVAL to indicate that any data in the buffer is not 160 * valid. 161 */ 162 if (boff == mfsp->mfs_size) { 163 bp->b_resid = bp->b_bcount; 164 bp->b_flags |= B_INVAL; 165 goto done; 166 } 167 bp->b_bcount = mfsp->mfs_size - boff; 168 } 169 170 /* 171 * Initiate I/O 172 */ 173 bioq_insert_tail(&mfsp->bio_queue, bio); 174 wakeup((caddr_t)mfsp); 175 return(0); 176 177 /* 178 * Failure conditions on bio 179 */ 180 bad: 181 bp->b_error = EINVAL; 182 error: 183 bp->b_flags |= B_ERROR | B_INVAL; 184 done: 185 biodone(bio); 186 return(0); 187 } 188 189 /* 190 * mfs_mount 191 * 192 * Called when mounting local physical media 193 * 194 * PARAMETERS: 195 * mountroot 196 * mp mount point structure 197 * path NULL (flag for root mount!!!) 198 * data <unused> 199 * ndp <unused> 200 * p process (user credentials check [statfs]) 201 * 202 * mount 203 * mp mount point structure 204 * path path to mount point 205 * data pointer to argument struct in user space 206 * ndp mount point namei() return (used for 207 * credentials on reload), reused to look 208 * up block device. 209 * p process (user credentials check) 210 * 211 * RETURNS: 0 Success 212 * !0 error number (errno.h) 213 * 214 * LOCK STATE: 215 * 216 * ENTRY 217 * mount point is locked 218 * EXIT 219 * mount point is locked 220 * 221 * NOTES: 222 * A NULL path can be used for a flag since the mount 223 * system call will fail with EFAULT in copyinstr in 224 * namei() if it is a genuine NULL from the user. 225 */ 226 /* ARGSUSED */ 227 static int 228 mfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred) 229 { 230 struct vnode *devvp; 231 struct mfs_args args; 232 struct ufsmount *ump; 233 struct fs *fs; 234 struct mfsnode *mfsp; 235 size_t size; 236 int flags, err; 237 int minnum; 238 cdev_t dev; 239 240 /* 241 * Use NULL path to flag a root mount 242 */ 243 if (path == NULL) { 244 /* 245 *** 246 * Mounting root file system 247 *** 248 */ 249 250 /* you lose */ 251 panic("mfs_mount: mount MFS as root: not configured!"); 252 } 253 254 /* 255 *** 256 * Mounting non-root file system or updating a file system 257 *** 258 */ 259 260 /* copy in user arguments*/ 261 if ((err = copyin(data, (caddr_t)&args, sizeof (struct mfs_args))) != 0) 262 goto error_1; 263 264 /* 265 * If updating, check whether changing from read-only to 266 * read/write; if there is no device name, that's all we do. 267 */ 268 if (mp->mnt_flag & MNT_UPDATE) { 269 /* 270 ******************** 271 * UPDATE 272 ******************** 273 */ 274 ump = VFSTOUFS(mp); 275 fs = ump->um_fs; 276 if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) { 277 flags = WRITECLOSE; 278 if (mp->mnt_flag & MNT_FORCE) 279 flags |= FORCECLOSE; 280 err = ffs_flushfiles(mp, flags); 281 if (err) 282 goto error_1; 283 } 284 if (fs->fs_ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) { 285 /* XXX reopen the device vnode read-write */ 286 fs->fs_ronly = 0; 287 } 288 /* if not updating name...*/ 289 if (args.fspec == 0) { 290 /* 291 * Process export requests. Jumping to "success" 292 * will return the vfs_export() error code. 293 */ 294 err = vfs_export(mp, &ump->um_export, &args.export); 295 goto success; 296 } 297 298 /* XXX MFS does not support name updating*/ 299 goto success; 300 } 301 /* 302 * Do the MALLOC before the getnewvnode since doing so afterward 303 * might cause a bogus v_data pointer to get dereferenced 304 * elsewhere if MALLOC should block. 305 */ 306 MALLOC(mfsp, struct mfsnode *, sizeof *mfsp, M_MFSNODE, M_WAITOK); 307 308 err = getspecialvnode(VT_MFS, NULL, &mfs_vnode_vops_p, &devvp, 0, 0); 309 if (err) { 310 FREE(mfsp, M_MFSNODE); 311 goto error_1; 312 } 313 314 minnum = (curproc->p_pid & 0xFF) | 315 ((curproc->p_pid & ~0xFF) << 8); 316 317 devvp->v_type = VCHR; 318 dev = make_dev(&mfs_ops, minnum, UID_ROOT, GID_WHEEL, 0600, 319 "MFS%d", minnum >> 16); 320 /* It is not clear that these will get initialized otherwise */ 321 dev->si_bsize_phys = DEV_BSIZE; 322 dev->si_iosize_max = DFLTPHYS; 323 dev->si_drv1 = mfsp; 324 addaliasu(devvp, mfs_ops.head.maj, minnum); 325 devvp->v_data = mfsp; 326 mfsp->mfs_baseoff = args.base; 327 mfsp->mfs_size = args.size; 328 mfsp->mfs_vnode = devvp; 329 mfsp->mfs_dev = reference_dev(dev); 330 mfsp->mfs_td = curthread; 331 mfsp->mfs_active = 1; 332 bioq_init(&mfsp->bio_queue); 333 334 /* 335 * Our 'block' device must be backed by a VM object. Theoretically 336 * we could use the anonymous memory VM object supplied by userland, 337 * but it would be somewhat of a complex task to deal with it 338 * that way since it would result in I/O requests which supply 339 * the VM pages from our own object. 340 * 341 * vnode_pager_alloc() is typically called when a VM object is 342 * being referenced externally. We have to undo the refs for 343 * the self reference between vnode and object. 344 */ 345 vnode_pager_alloc(devvp, args.size, 0, 0); 346 vrele(devvp); 347 --devvp->v_object->ref_count; 348 349 /* Save "mounted from" info for mount point (NULL pad)*/ 350 copyinstr( args.fspec, /* device name*/ 351 mp->mnt_stat.f_mntfromname, /* save area*/ 352 MNAMELEN - 1, /* max size*/ 353 &size); /* real size*/ 354 bzero( mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 355 356 vx_unlock(devvp); 357 if ((err = ffs_mountfs(devvp, mp, M_MFSNODE)) != 0) { 358 mfsp->mfs_active = 0; 359 goto error_2; 360 } 361 362 /* 363 * Initialize FS stat information in mount struct; uses 364 * mp->mnt_stat.f_mntfromname. 365 * 366 * This code is common to root and non-root mounts 367 */ 368 VFS_STATFS(mp, &mp->mnt_stat, cred); 369 370 goto success; 371 372 error_2: /* error with devvp held*/ 373 374 /* release devvp before failing*/ 375 vrele(devvp); 376 377 error_1: /* no state to back out*/ 378 379 success: 380 return( err); 381 } 382 383 /* 384 * Used to grab the process and keep it in the kernel to service 385 * memory filesystem I/O requests. 386 * 387 * Loop servicing I/O requests. 388 * Copy the requested data into or out of the memory filesystem 389 * address space. 390 */ 391 /* ARGSUSED */ 392 static int 393 mfs_start(struct mount *mp, int flags) 394 { 395 struct vnode *vp = VFSTOUFS(mp)->um_devvp; 396 struct mfsnode *mfsp = VTOMFS(vp); 397 struct bio *bio; 398 struct buf *bp; 399 int gotsig = 0, sig; 400 thread_t td = curthread; 401 402 /* 403 * We must prevent the system from trying to swap 404 * out or kill ( when swap space is low, see vm/pageout.c ) the 405 * process. A deadlock can occur if the process is swapped out, 406 * and the system can loop trying to kill the unkillable ( while 407 * references exist ) MFS process when swap space is low. 408 */ 409 KKASSERT(curproc); 410 PHOLD(curproc); 411 412 mfsp->mfs_td = td; 413 414 while (mfsp->mfs_active) { 415 crit_enter(); 416 417 while ((bio = bioq_first(&mfsp->bio_queue)) != NULL) { 418 bioq_remove(&mfsp->bio_queue, bio); 419 crit_exit(); 420 bp = bio->bio_buf; 421 mfs_doio(bio, mfsp); 422 wakeup(bp); 423 crit_enter(); 424 } 425 426 crit_exit(); 427 428 /* 429 * If a non-ignored signal is received, try to unmount. 430 * If that fails, clear the signal (it has been "processed"), 431 * otherwise we will loop here, as tsleep will always return 432 * EINTR/ERESTART. 433 */ 434 /* 435 * Note that dounmount() may fail if work was queued after 436 * we slept. We have to jump hoops here to make sure that we 437 * process any buffers after the sleep, before we dounmount() 438 */ 439 if (gotsig) { 440 gotsig = 0; 441 if (dounmount(mp, 0) != 0) { 442 KKASSERT(td->td_proc); 443 sig = CURSIG(td->td_lwp); 444 if (sig) 445 lwp_delsig(td->td_lwp, sig); 446 } 447 } 448 else if (tsleep((caddr_t)mfsp, PCATCH, "mfsidl", 0)) 449 gotsig++; /* try to unmount in next pass */ 450 } 451 PRELE(curproc); 452 v_release_rdev(vp); /* hack because we do not implement CLOSE */ 453 /* XXX destroy/release devvp */ 454 return (0); 455 } 456 457 /* 458 * Get file system statistics. 459 */ 460 static int 461 mfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred) 462 { 463 int error; 464 465 error = ffs_statfs(mp, sbp, cred); 466 sbp->f_type = mp->mnt_vfc->vfc_typenum; 467 return (error); 468 } 469 470 /* 471 * Memory based filesystem initialization. 472 */ 473 static int 474 mfs_init(struct vfsconf *vfsp) 475 { 476 dev_ops_add(&mfs_ops, 0, 0); 477 return (0); 478 } 479