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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)mfs_vfsops.c 8.11 (Berkeley) 6/19/95 30 * $FreeBSD: src/sys/ufs/mfs/mfs_vfsops.c,v 1.81.2.3 2001/07/04 17:35:21 tegge Exp $ 31 */ 32 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/conf.h> 37 #include <sys/device.h> 38 #include <sys/kernel.h> 39 #include <sys/proc.h> 40 #include <sys/buf.h> 41 #include <sys/mount.h> 42 #include <sys/signalvar.h> 43 #include <sys/signal2.h> 44 #include <sys/vnode.h> 45 #include <sys/malloc.h> 46 #include <sys/sysproto.h> 47 #include <sys/mman.h> 48 #include <sys/linker.h> 49 #include <sys/fcntl.h> 50 #include <sys/nlookup.h> 51 #include <sys/devfs.h> 52 53 #include <vm/vm.h> 54 #include <vm/vm_object.h> 55 #include <vm/vm_page.h> 56 #include <vm/vm_pager.h> 57 #include <vm/vnode_pager.h> 58 #include <vm/vm_extern.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 static int mfs_mount (struct mount *mp, 76 char *path, caddr_t data, struct ucred *td); 77 static int mfs_start (struct mount *mp, int flags); 78 static int mfs_statfs (struct mount *mp, struct statfs *sbp, 79 struct ucred *cred); 80 static int mfs_init (struct vfsconf *); 81 static void mfs_doio(struct bio *bio, struct mfsnode *mfsp); 82 83 d_open_t mfsopen; 84 d_close_t mfsclose; 85 d_strategy_t mfsstrategy; 86 87 static struct dev_ops mfs_ops = { 88 { "MFS", -1, D_DISK }, 89 .d_open = mfsopen, 90 .d_close = mfsclose, 91 .d_read = physread, 92 .d_write = physwrite, 93 .d_strategy = mfsstrategy, 94 }; 95 96 /* 97 * mfs vfs operations. 98 */ 99 static struct vfsops mfs_vfsops = { 100 .vfs_mount = mfs_mount, 101 .vfs_start = mfs_start, 102 .vfs_unmount = ffs_unmount, 103 .vfs_root = ufs_root, 104 .vfs_quotactl = ufs_quotactl, 105 .vfs_statfs = mfs_statfs, 106 .vfs_sync = ffs_sync, 107 .vfs_vget = ffs_vget, 108 .vfs_fhtovp = ffs_fhtovp, 109 .vfs_checkexp = ufs_check_export, 110 .vfs_vptofh = ffs_vptofh, 111 .vfs_init = mfs_init 112 }; 113 114 VFS_SET(mfs_vfsops, mfs, 0); 115 MODULE_VERSION(mfs, 1); 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 0 126 if (ap->a_oflags & FWRITE) 127 return(EROFS); 128 #endif 129 if (dev->si_drv1) 130 return(0); 131 return(ENXIO); 132 } 133 134 int 135 mfsclose(struct dev_close_args *ap) 136 { 137 cdev_t dev = ap->a_head.a_dev; 138 struct mfsnode *mfsp; 139 140 if ((mfsp = dev->si_drv1) == NULL) 141 return(0); 142 mfsp->mfs_active = 0; 143 wakeup((caddr_t)mfsp); 144 return(0); 145 } 146 147 int 148 mfsstrategy(struct dev_strategy_args *ap) 149 { 150 cdev_t dev = ap->a_head.a_dev; 151 struct bio *bio = ap->a_bio; 152 struct buf *bp = bio->bio_buf; 153 off_t boff = bio->bio_offset; 154 off_t eoff = boff + bp->b_bcount; 155 struct mfsnode *mfsp; 156 157 if ((mfsp = dev->si_drv1) == NULL) { 158 bp->b_error = ENXIO; 159 goto error; 160 } 161 if (boff < 0) 162 goto bad; 163 if (eoff > mfsp->mfs_size) { 164 if (boff > mfsp->mfs_size || (bp->b_flags & B_BNOCLIP)) 165 goto bad; 166 /* 167 * Return EOF by completing the I/O with 0 bytes transfered. 168 * Set B_INVAL to indicate that any data in the buffer is not 169 * valid. 170 */ 171 if (boff == mfsp->mfs_size) { 172 bp->b_resid = bp->b_bcount; 173 bp->b_flags |= B_INVAL; 174 goto done; 175 } 176 bp->b_bcount = mfsp->mfs_size - boff; 177 } 178 179 /* 180 * Initiate I/O 181 */ 182 if (mfsp->mfs_td == curthread) { 183 mfs_doio(bio, mfsp); 184 } else { 185 bioq_insert_tail(&mfsp->bio_queue, bio); 186 wakeup((caddr_t)mfsp); 187 } 188 return(0); 189 190 /* 191 * Failure conditions on bio 192 */ 193 bad: 194 bp->b_error = EINVAL; 195 error: 196 bp->b_flags |= B_ERROR | B_INVAL; 197 done: 198 biodone(bio); 199 return(0); 200 } 201 202 /* 203 * mfs_mount 204 * 205 * Called when mounting local physical media 206 * 207 * PARAMETERS: 208 * mountroot 209 * mp mount point structure 210 * path NULL (flag for root mount!!!) 211 * data <unused> 212 * ndp <unused> 213 * p process (user credentials check [statfs]) 214 * 215 * mount 216 * mp mount point structure 217 * path path to mount point 218 * data pointer to argument struct in user space 219 * ndp mount point namei() return (used for 220 * credentials on reload), reused to look 221 * up block device. 222 * p process (user credentials check) 223 * 224 * RETURNS: 0 Success 225 * !0 error number (errno.h) 226 * 227 * LOCK STATE: 228 * 229 * ENTRY 230 * mount point is locked 231 * EXIT 232 * mount point is locked 233 * 234 * NOTES: 235 * A NULL path can be used for a flag since the mount 236 * system call will fail with EFAULT in copyinstr in 237 * namei() if it is a genuine NULL from the user. 238 */ 239 /* ARGSUSED */ 240 static int 241 mfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred) 242 { 243 struct vnode *devvp; 244 struct mfs_args args; 245 struct ufsmount *ump; 246 struct fs *fs; 247 struct mfsnode *mfsp; 248 struct nlookupdata nd; 249 size_t size; 250 char devname[16]; 251 int flags; 252 int minnum; 253 int error; 254 cdev_t dev; 255 256 /* 257 * Use NULL path to flag a root mount 258 */ 259 if (path == NULL) { 260 /* 261 *** 262 * Mounting root file system 263 *** 264 */ 265 266 /* you lose */ 267 panic("mfs_mount: mount MFS as root: not configured!"); 268 } 269 270 mfsp = NULL; 271 272 /* 273 *** 274 * Mounting non-root file system or updating a file system 275 *** 276 */ 277 278 /* copy in user arguments*/ 279 error = copyin(data, (caddr_t)&args, sizeof (struct mfs_args)); 280 if (error) 281 goto error_1; 282 283 /* 284 * If updating, check whether changing from read-only to 285 * read/write; if there is no device name, that's all we do. 286 */ 287 if (mp->mnt_flag & MNT_UPDATE) { 288 /* 289 ******************** 290 * UPDATE 291 ******************** 292 */ 293 ump = VFSTOUFS(mp); 294 fs = ump->um_fs; 295 if (fs->fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) { 296 flags = WRITECLOSE; 297 if (mp->mnt_flag & MNT_FORCE) 298 flags |= FORCECLOSE; 299 error = ffs_flushfiles(mp, flags); 300 if (error) 301 goto error_1; 302 } 303 if (fs->fs_ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) { 304 /* XXX reopen the device vnode read-write */ 305 fs->fs_ronly = 0; 306 } 307 /* if not updating name...*/ 308 if (args.fspec == 0) { 309 /* 310 * Process export requests. Jumping to "success" 311 * will return the vfs_export() error code. 312 */ 313 error = vfs_export(mp, &ump->um_export, &args.export); 314 goto success; 315 } 316 317 /* XXX MFS does not support name updating*/ 318 goto success; 319 } 320 321 /* 322 * Do the MALLOC before the make_dev since doing so afterward 323 * might cause a bogus v_data pointer to get dereferenced 324 * elsewhere if MALLOC should block. 325 */ 326 mfsp = kmalloc(sizeof *mfsp, M_MFSNODE, M_WAITOK | M_ZERO); 327 328 minnum = (int)curproc->p_pid; 329 330 dev = make_dev(&mfs_ops, minnum, UID_ROOT, GID_WHEEL, 0600, 331 "mfs%d", minnum); 332 /* It is not clear that these will get initialized otherwise */ 333 dev->si_bsize_phys = DEV_BSIZE; 334 dev->si_iosize_max = MAXPHYS; 335 dev->si_drv1 = mfsp; 336 mfsp->mfs_baseoff = args.base; 337 mfsp->mfs_size = args.size; 338 mfsp->mfs_dev = dev; 339 mfsp->mfs_td = curthread; 340 mfsp->mfs_active = 1; 341 bioq_init(&mfsp->bio_queue); 342 343 devfs_config(); /* sync devfs work */ 344 ksnprintf(devname, sizeof(devname), "/dev/mfs%d", minnum); 345 nlookup_init(&nd, devname, UIO_SYSSPACE, 0); 346 devvp = NULL; 347 error = nlookup(&nd); 348 if (error == 0) { 349 devvp = nd.nl_nch.ncp->nc_vp; 350 if (devvp == NULL) 351 error = ENOENT; 352 error = vget(devvp, LK_SHARED); 353 } 354 nlookup_done(&nd); 355 356 if (error) 357 goto error_1; 358 vn_unlock(devvp); 359 360 /* 361 * Our 'block' device must be backed by a VM object. Theoretically 362 * we could use the anonymous memory VM object supplied by userland, 363 * but it would be somewhat of a complex task to deal with it 364 * that way since it would result in I/O requests which supply 365 * the VM pages from our own object. 366 * 367 * vnode_pager_alloc() is typically called when a VM object is 368 * being referenced externally. We have to undo the refs for 369 * the self reference between vnode and object. 370 */ 371 vnode_pager_setsize(devvp, args.size); 372 373 /* Save "mounted from" info for mount point (NULL pad)*/ 374 copyinstr(args.fspec, /* device name*/ 375 mp->mnt_stat.f_mntfromname, /* save area*/ 376 MNAMELEN - 1, /* max size*/ 377 &size); /* real size*/ 378 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size); 379 /* vref is eaten by mount? */ 380 381 error = ffs_mountfs(devvp, mp, M_MFSNODE); 382 if (error) { 383 mfsp->mfs_active = 0; 384 goto error_2; 385 } 386 387 /* 388 * Initialize FS stat information in mount struct; uses 389 * mp->mnt_stat.f_mntfromname. 390 * 391 * This code is common to root and non-root mounts 392 */ 393 VFS_STATFS(mp, &mp->mnt_stat, cred); 394 395 /* 396 * Mark VFS_START MPSAFE; this is to avoid accessing 397 * per-mount token after VFS_START exits 398 */ 399 mp->mnt_kern_flag |= MNTK_ST_MPSAFE; 400 401 goto success; 402 403 error_2: /* error with devvp held*/ 404 vrele(devvp); 405 406 error_1: /* no state to back out*/ 407 if (mfsp) { 408 if (mfsp->mfs_dev) { 409 destroy_dev(mfsp->mfs_dev); 410 mfsp->mfs_dev = NULL; 411 } 412 kfree(mfsp, M_MFSNODE); 413 } 414 415 success: 416 return(error); 417 } 418 419 /* 420 * Used to grab the process and keep it in the kernel to service 421 * memory filesystem I/O requests. 422 * 423 * Loop servicing I/O requests. 424 * Copy the requested data into or out of the memory filesystem 425 * address space. 426 */ 427 /* ARGSUSED */ 428 static int 429 mfs_start(struct mount *mp, int flags) 430 { 431 struct vnode *vp = VFSTOUFS(mp)->um_devvp; 432 struct mfsnode *mfsp = vp->v_rdev->si_drv1; 433 struct bio *bio; 434 struct buf *bp; 435 int gotsig = 0, sig; 436 thread_t td = curthread; 437 438 /* 439 * We must prevent the system from trying to swap 440 * out or kill ( when swap space is low, see vm/pageout.c ) the 441 * process. A deadlock can occur if the process is swapped out, 442 * and the system can loop trying to kill the unkillable ( while 443 * references exist ) MFS process when swap space is low. 444 */ 445 KKASSERT(curproc); 446 PHOLD(curproc); 447 448 mfsp->mfs_td = td; 449 450 while (mfsp->mfs_active) { 451 crit_enter(); 452 453 while ((bio = bioq_takefirst(&mfsp->bio_queue)) != NULL) { 454 crit_exit(); 455 bp = bio->bio_buf; 456 mfs_doio(bio, mfsp); 457 wakeup(bp); 458 crit_enter(); 459 } 460 461 crit_exit(); 462 463 /* 464 * If a non-ignored signal is received, try to unmount. 465 * If that fails, clear the signal (it has been "processed"), 466 * otherwise we will loop here, as tsleep will always return 467 * EINTR/ERESTART. 468 */ 469 /* 470 * Note that dounmount() may fail if work was queued after 471 * we slept. We have to jump hoops here to make sure that we 472 * process any buffers after the sleep, before we dounmount() 473 */ 474 if (gotsig) { 475 gotsig = 0; 476 if (dounmount(mp, 0) != 0) { 477 KKASSERT(td->td_proc); 478 sig = CURSIG(td->td_lwp); 479 if (sig) { 480 spin_lock(&td->td_lwp->lwp_spin); 481 lwp_delsig(td->td_lwp, sig); 482 spin_unlock(&td->td_lwp->lwp_spin); 483 } 484 } 485 } 486 else if (tsleep((caddr_t)mfsp, PCATCH, "mfsidl", 0)) 487 gotsig++; /* try to unmount in next pass */ 488 } 489 PRELE(curproc); 490 if (mfsp->mfs_dev) { 491 destroy_dev(mfsp->mfs_dev); 492 mfsp->mfs_dev = NULL; 493 } 494 kfree(mfsp, M_MFSNODE); 495 return (EMOUNTEXIT); 496 } 497 498 /* 499 * Get file system statistics. 500 */ 501 static int 502 mfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred) 503 { 504 int error; 505 506 error = ffs_statfs(mp, sbp, cred); 507 sbp->f_type = mp->mnt_vfc->vfc_typenum; 508 return (error); 509 } 510 511 /* 512 * Memory based filesystem initialization. 513 */ 514 static int 515 mfs_init(struct vfsconf *vfsp) 516 { 517 return (0); 518 } 519 520 /* 521 * Memory file system I/O. 522 * 523 * Trivial on the HP since buffer has already been mapping into KVA space. 524 * 525 * Read and Write are handled with a simple copyin and copyout. 526 * 527 * We also partially support VOP_FREEBLKS(). We can't implement 528 * completely -- for example, on fragments or inode metadata, but we can 529 * implement it for page-aligned requests. 530 */ 531 static void 532 mfs_doio(struct bio *bio, struct mfsnode *mfsp) 533 { 534 struct buf *bp = bio->bio_buf; 535 caddr_t base = mfsp->mfs_baseoff + bio->bio_offset; 536 int bytes; 537 538 switch(bp->b_cmd) { 539 case BUF_CMD_FREEBLKS: 540 /* 541 * Implement FREEBLKS, which allows the filesystem to tell 542 * a block device when blocks are no longer needed (like when 543 * a file is deleted). We use the hook to MADV_FREE the VM. 544 * This makes an MFS filesystem work as well or better then 545 * a sun-style swap-mounted filesystem. 546 */ 547 bytes = bp->b_bcount; 548 549 if ((vm_offset_t)base & PAGE_MASK) { 550 int n = PAGE_SIZE - ((vm_offset_t)base & PAGE_MASK); 551 bytes -= n; 552 base += n; 553 } 554 if (bytes > 0) { 555 struct madvise_args uap; 556 557 bytes &= ~PAGE_MASK; 558 if (bytes != 0) { 559 bzero(&uap, sizeof(uap)); 560 uap.addr = base; 561 uap.len = bytes; 562 uap.behav = MADV_FREE; 563 sys_madvise(&uap); 564 } 565 } 566 bp->b_error = 0; 567 break; 568 case BUF_CMD_READ: 569 /* 570 * Read data from our 'memory' disk 571 */ 572 bp->b_error = copyin(base, bp->b_data, bp->b_bcount); 573 break; 574 case BUF_CMD_WRITE: 575 /* 576 * Write data to our 'memory' disk 577 */ 578 bp->b_error = copyout(bp->b_data, base, bp->b_bcount); 579 break; 580 default: 581 panic("mfs: bad b_cmd %d", bp->b_cmd); 582 } 583 if (bp->b_error) 584 bp->b_flags |= B_ERROR; 585 biodone(bio); 586 } 587