ext2fs_readwrite.c revision 1.71
1 /* $NetBSD: ext2fs_readwrite.c,v 1.71 2015/03/28 17:06:15 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)ufs_readwrite.c 8.8 (Berkeley) 8/4/94 32 * Modified for ext2fs by Manuel Bouyer. 33 */ 34 35 /*- 36 * Copyright (c) 1997 Manuel Bouyer. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 47 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 48 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 49 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 50 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 51 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 52 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 53 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 54 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 55 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 56 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 57 * 58 * @(#)ufs_readwrite.c 8.8 (Berkeley) 8/4/94 59 * Modified for ext2fs by Manuel Bouyer. 60 */ 61 62 #include <sys/cdefs.h> 63 __KERNEL_RCSID(0, "$NetBSD: ext2fs_readwrite.c,v 1.71 2015/03/28 17:06:15 riastradh Exp $"); 64 65 #include <sys/param.h> 66 #include <sys/systm.h> 67 #include <sys/resourcevar.h> 68 #include <sys/kernel.h> 69 #include <sys/file.h> 70 #include <sys/stat.h> 71 #include <sys/buf.h> 72 #include <sys/proc.h> 73 #include <sys/mount.h> 74 #include <sys/vnode.h> 75 #include <sys/signalvar.h> 76 #include <sys/kauth.h> 77 78 #include <ufs/ufs/inode.h> 79 #include <ufs/ufs/ufsmount.h> 80 #include <ufs/ufs/ufs_extern.h> 81 #include <ufs/ext2fs/ext2fs.h> 82 #include <ufs/ext2fs/ext2fs_extern.h> 83 84 static int ext2fs_post_read_update(struct vnode *, int, int); 85 static int ext2fs_post_write_update(struct vnode *, struct uio *, int, 86 kauth_cred_t, off_t, int, int, int); 87 88 /* 89 * Vnode op for reading. 90 */ 91 /* ARGSUSED */ 92 int 93 ext2fs_read(void *v) 94 { 95 struct vop_read_args /* { 96 struct vnode *a_vp; 97 struct uio *a_uio; 98 int a_ioflag; 99 kauth_cred_t a_cred; 100 } */ *ap = v; 101 struct vnode *vp; 102 struct inode *ip; 103 struct uio *uio; 104 struct ufsmount *ump; 105 vsize_t bytelen; 106 int advice; 107 int error; 108 109 vp = ap->a_vp; 110 ip = VTOI(vp); 111 ump = ip->i_ump; 112 uio = ap->a_uio; 113 error = 0; 114 115 KASSERT(uio->uio_rw == UIO_READ); 116 KASSERT(vp->v_type == VREG || vp->v_type == VDIR); 117 118 /* XXX Eliminate me by refusing directory reads from userland. */ 119 if (vp->v_type == VDIR) 120 return ext2fs_bufrd(vp, uio, ap->a_ioflag, ap->a_cred); 121 122 if ((uint64_t)uio->uio_offset > ump->um_maxfilesize) 123 return (EFBIG); 124 if (uio->uio_resid == 0) 125 return (0); 126 if (uio->uio_offset >= ext2fs_size(ip)) 127 goto out; 128 129 KASSERT(vp->v_type == VREG); 130 advice = IO_ADV_DECODE(ap->a_ioflag); 131 while (uio->uio_resid > 0) { 132 bytelen = MIN(ext2fs_size(ip) - uio->uio_offset, 133 uio->uio_resid); 134 if (bytelen == 0) 135 break; 136 137 error = ubc_uiomove(&vp->v_uobj, uio, bytelen, advice, 138 UBC_READ | UBC_PARTIALOK | UBC_UNMAP_FLAG(vp)); 139 if (error) 140 break; 141 } 142 143 out: 144 error = ext2fs_post_read_update(vp, ap->a_ioflag, error); 145 return (error); 146 } 147 148 /* 149 * UFS op for reading via the buffer cache 150 */ 151 int 152 ext2fs_bufrd(struct vnode *vp, struct uio *uio, int ioflag, kauth_cred_t cred) 153 { 154 struct inode *ip; 155 struct ufsmount *ump; 156 struct m_ext2fs *fs; 157 struct buf *bp; 158 off_t bytesinfile; 159 daddr_t lbn, nextlbn; 160 long size, xfersize, blkoffset; 161 int error; 162 163 KASSERT(uio->uio_rw == UIO_READ); 164 KASSERT(VOP_ISLOCKED(vp)); 165 KASSERT(vp->v_type == VDIR || vp->v_type == VLNK); 166 167 ip = VTOI(vp); 168 ump = ip->i_ump; 169 fs = ip->i_e2fs; 170 error = 0; 171 172 KASSERT(vp->v_type != VLNK || 173 ext2fs_size(ip) >= ump->um_maxsymlinklen); 174 KASSERT(vp->v_type != VLNK || ump->um_maxsymlinklen != 0 || 175 ext2fs_nblock(ip) != 0); 176 177 if (uio->uio_offset > ump->um_maxfilesize) 178 return EFBIG; 179 if (uio->uio_resid == 0) 180 return 0; 181 if (uio->uio_offset >= ext2fs_size(ip)) 182 goto out; 183 184 for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { 185 bytesinfile = ext2fs_size(ip) - uio->uio_offset; 186 if (bytesinfile <= 0) 187 break; 188 lbn = ext2_lblkno(fs, uio->uio_offset); 189 nextlbn = lbn + 1; 190 size = fs->e2fs_bsize; 191 blkoffset = ext2_blkoff(fs, uio->uio_offset); 192 xfersize = fs->e2fs_bsize - blkoffset; 193 if (uio->uio_resid < xfersize) 194 xfersize = uio->uio_resid; 195 if (bytesinfile < xfersize) 196 xfersize = bytesinfile; 197 198 if (ext2_lblktosize(fs, nextlbn) >= ext2fs_size(ip)) 199 error = bread(vp, lbn, size, NOCRED, 0, &bp); 200 else { 201 int nextsize = fs->e2fs_bsize; 202 error = breadn(vp, lbn, 203 size, &nextlbn, &nextsize, 1, NOCRED, 0, &bp); 204 } 205 if (error) 206 break; 207 208 /* 209 * We should only get non-zero b_resid when an I/O error 210 * has occurred, which should cause us to break above. 211 * However, if the short read did not cause an error, 212 * then we want to ensure that we do not uiomove bad 213 * or uninitialized data. 214 */ 215 size -= bp->b_resid; 216 if (size < xfersize) { 217 if (size == 0) 218 break; 219 xfersize = size; 220 } 221 error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio); 222 if (error) 223 break; 224 brelse(bp, 0); 225 } 226 if (bp != NULL) 227 brelse(bp, 0); 228 229 out: 230 error = ext2fs_post_read_update(vp, ioflag, error); 231 return (error); 232 } 233 234 static int 235 ext2fs_post_read_update(struct vnode *vp, int ioflag, int error) 236 { 237 struct inode *ip = VTOI(vp); 238 239 if (!(vp->v_mount->mnt_flag & MNT_NOATIME)) { 240 ip->i_flag |= IN_ACCESS; 241 if ((ioflag & IO_SYNC) == IO_SYNC) 242 error = ext2fs_update(vp, NULL, NULL, UPDATE_WAIT); 243 } 244 245 return error; 246 } 247 248 /* 249 * Vnode op for writing. 250 */ 251 int 252 ext2fs_write(void *v) 253 { 254 struct vop_write_args /* { 255 struct vnode *a_vp; 256 struct uio *a_uio; 257 int a_ioflag; 258 kauth_cred_t a_cred; 259 } */ *ap = v; 260 struct vnode *vp; 261 struct uio *uio; 262 struct inode *ip; 263 struct m_ext2fs *fs; 264 struct ufsmount *ump; 265 off_t osize; 266 int blkoffset, error, ioflag, resid; 267 vsize_t bytelen; 268 off_t oldoff = 0; /* XXX */ 269 bool async; 270 int extended = 0; 271 int advice; 272 273 ioflag = ap->a_ioflag; 274 advice = IO_ADV_DECODE(ioflag); 275 uio = ap->a_uio; 276 vp = ap->a_vp; 277 ip = VTOI(vp); 278 ump = ip->i_ump; 279 error = 0; 280 281 KASSERT(uio->uio_rw == UIO_WRITE); 282 KASSERT(vp->v_type == VREG); 283 284 if (ioflag & IO_APPEND) 285 uio->uio_offset = ext2fs_size(ip); 286 if ((ip->i_e2fs_flags & EXT2_APPEND) && 287 uio->uio_offset != ext2fs_size(ip)) 288 return (EPERM); 289 290 fs = ip->i_e2fs; 291 if (uio->uio_offset < 0 || 292 (uint64_t)uio->uio_offset + uio->uio_resid > ump->um_maxfilesize) 293 return (EFBIG); 294 if (uio->uio_resid == 0) 295 return (0); 296 297 async = vp->v_mount->mnt_flag & MNT_ASYNC; 298 resid = uio->uio_resid; 299 osize = ext2fs_size(ip); 300 301 KASSERT(vp->v_type == VREG); 302 while (uio->uio_resid > 0) { 303 oldoff = uio->uio_offset; 304 blkoffset = ext2_blkoff(fs, uio->uio_offset); 305 bytelen = MIN(fs->e2fs_bsize - blkoffset, uio->uio_resid); 306 307 if (vp->v_size < oldoff + bytelen) { 308 uvm_vnp_setwritesize(vp, oldoff + bytelen); 309 } 310 error = ufs_balloc_range(vp, uio->uio_offset, bytelen, 311 ap->a_cred, 0); 312 if (error) 313 break; 314 error = ubc_uiomove(&vp->v_uobj, uio, bytelen, advice, 315 UBC_WRITE | UBC_UNMAP_FLAG(vp)); 316 if (error) 317 break; 318 319 /* 320 * update UVM's notion of the size now that we've 321 * copied the data into the vnode's pages. 322 */ 323 324 if (vp->v_size < uio->uio_offset) { 325 uvm_vnp_setsize(vp, uio->uio_offset); 326 extended = 1; 327 } 328 329 /* 330 * flush what we just wrote if necessary. 331 * XXXUBC simplistic async flushing. 332 */ 333 334 if (!async && oldoff >> 16 != uio->uio_offset >> 16) { 335 mutex_enter(vp->v_interlock); 336 error = VOP_PUTPAGES(vp, (oldoff >> 16) << 16, 337 (uio->uio_offset >> 16) << 16, 338 PGO_CLEANIT | PGO_LAZY); 339 } 340 } 341 if (error == 0 && ioflag & IO_SYNC) { 342 mutex_enter(vp->v_interlock); 343 error = VOP_PUTPAGES(vp, trunc_page(oldoff), 344 round_page(ext2_blkroundup(fs, uio->uio_offset)), 345 PGO_CLEANIT | PGO_SYNCIO); 346 } 347 348 error = ext2fs_post_write_update(vp, uio, ioflag, ap->a_cred, osize, 349 resid, extended, error); 350 return (error); 351 } 352 353 /* 354 * UFS op for writing via the buffer cache 355 */ 356 int 357 ext2fs_bufwr(struct vnode *vp, struct uio *uio, int ioflag, kauth_cred_t cred) 358 { 359 struct inode *ip; 360 struct ufsmount *ump; 361 struct m_ext2fs *fs; 362 struct buf *bp; 363 int flags; 364 off_t osize; 365 daddr_t lbn; 366 int resid, blkoffset, xfersize; 367 int extended = 0; 368 int error; 369 370 KASSERT(VOP_ISLOCKED(vp) == LK_EXCLUSIVE); 371 KASSERT(vp->v_type == VDIR || vp->v_type == VLNK); 372 KASSERT(vp->v_type != VDIR || ISSET(ioflag, IO_SYNC)); 373 KASSERT(uio->uio_rw == UIO_WRITE); 374 375 ip = VTOI(vp); 376 ump = ip->i_ump; 377 fs = ip->i_e2fs; 378 error = 0; 379 380 if (uio->uio_offset < 0 || 381 uio->uio_resid > ump->um_maxfilesize || 382 uio->uio_offset > (ump->um_maxfilesize - uio->uio_resid)) 383 return EFBIG; 384 if (uio->uio_resid == 0) 385 return 0; 386 387 flags = ioflag & IO_SYNC ? B_SYNC : 0; 388 resid = uio->uio_resid; 389 osize = ext2fs_size(ip); 390 391 for (error = 0; uio->uio_resid > 0;) { 392 lbn = ext2_lblkno(fs, uio->uio_offset); 393 blkoffset = ext2_blkoff(fs, uio->uio_offset); 394 xfersize = MIN(fs->e2fs_bsize - blkoffset, uio->uio_resid); 395 if (xfersize < fs->e2fs_bsize) 396 flags |= B_CLRBUF; 397 else 398 flags &= ~B_CLRBUF; 399 error = ext2fs_balloc(ip, lbn, blkoffset + xfersize, cred, &bp, 400 flags); 401 if (error) 402 break; 403 if (ext2fs_size(ip) < uio->uio_offset + xfersize) { 404 error = ext2fs_setsize(ip, uio->uio_offset + xfersize); 405 if (error) 406 break; 407 } 408 error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio); 409 410 /* 411 * update UVM's notion of the size now that we've 412 * copied the data into the vnode's pages. 413 */ 414 415 if (vp->v_size < uio->uio_offset) { 416 uvm_vnp_setsize(vp, uio->uio_offset); 417 extended = 1; 418 } 419 420 if (ioflag & IO_SYNC) 421 (void)bwrite(bp); 422 else if (xfersize + blkoffset == fs->e2fs_bsize) 423 bawrite(bp); 424 else 425 bdwrite(bp); 426 if (error || xfersize == 0) 427 break; 428 } 429 430 error = ext2fs_post_write_update(vp, uio, ioflag, cred, osize, resid, 431 extended, error); 432 return (error); 433 } 434 435 static int 436 ext2fs_post_write_update(struct vnode *vp, struct uio *uio, int ioflag, 437 kauth_cred_t cred, off_t osize, int resid, int extended, int error) 438 { 439 struct inode *ip = VTOI(vp); 440 441 /* Trigger ctime and mtime updates, and atime if MNT_RELATIME. */ 442 ip->i_flag |= IN_CHANGE | IN_UPDATE; 443 if (vp->v_mount->mnt_flag & MNT_RELATIME) 444 ip->i_flag |= IN_ACCESS; 445 446 /* 447 * If we successfully wrote any data and we are not the superuser, 448 * we clear the setuid and setgid bits as a precaution against 449 * tampering. 450 */ 451 if (resid > uio->uio_resid && cred) { 452 if (ip->i_e2fs_mode & ISUID) { 453 if (kauth_authorize_vnode(cred, 454 KAUTH_VNODE_RETAIN_SUID, vp, NULL, EPERM) != 0) 455 ip->i_e2fs_mode &= ISUID; 456 } 457 458 if (ip->i_e2fs_mode & ISGID) { 459 if (kauth_authorize_vnode(cred, 460 KAUTH_VNODE_RETAIN_SGID, vp, NULL, EPERM) != 0) 461 ip->i_e2fs_mode &= ~ISGID; 462 } 463 } 464 465 /* If we successfully wrote anything, notify kevent listeners. */ 466 if (resid > uio->uio_resid) 467 VN_KNOTE(vp, NOTE_WRITE | (extended ? NOTE_EXTEND : 0)); 468 469 /* 470 * Update the size on disk: truncate back to original size on 471 * error, or reflect the new size on success. 472 */ 473 if (error) { 474 (void) ext2fs_truncate(vp, osize, ioflag & IO_SYNC, cred); 475 uio->uio_offset -= resid - uio->uio_resid; 476 uio->uio_resid = resid; 477 } else if (resid > uio->uio_resid && (ioflag & IO_SYNC) == IO_SYNC) 478 error = ext2fs_update(vp, NULL, NULL, UPDATE_WAIT); 479 480 /* Make sure the vnode uvm size matches the inode file size. */ 481 KASSERT(vp->v_size == ext2fs_size(ip)); 482 483 return error; 484 } 485
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