1 /*- 2 * Copyright (c) 1993 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 * @(#)ufs_readwrite.c 8.11 (Berkeley) 5/8/95 34 * $FreeBSD: src/sys/ufs/ufs/ufs_readwrite.c,v 1.65.2.14 2003/04/04 22:21:29 tegge Exp $ 35 * $DragonFly: src/sys/vfs/ufs/ufs_readwrite.c,v 1.26 2008/06/19 23:27:39 dillon Exp $ 36 */ 37 38 #define BLKSIZE(a, b, c) blksize(a, b, c) 39 #define FS struct fs 40 #define I_FS i_fs 41 42 #include <vm/vm.h> 43 #include <vm/vm_object.h> 44 #include <vm/vm_pager.h> 45 #include <vm/vm_map.h> 46 #include <vm/vnode_pager.h> 47 #include <sys/event.h> 48 #include <sys/vmmeter.h> 49 #include <sys/sysctl.h> 50 #include <vm/vm_page2.h> 51 52 #include "opt_directio.h" 53 54 #define VN_KNOTE(vp, b) \ 55 KNOTE((struct klist *)&vp->v_pollinfo.vpi_kqinfo.ki_note, (b)) 56 57 #ifdef DIRECTIO 58 extern int ffs_rawread(struct vnode *vp, struct uio *uio, int *workdone); 59 #endif 60 61 SYSCTL_DECL(_vfs_ffs); 62 63 /* 64 * Vnode op for reading. 65 * 66 * ffs_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag, 67 * struct ucred *a_cred) 68 */ 69 /* ARGSUSED */ 70 int 71 ffs_read(struct vop_read_args *ap) 72 { 73 struct vnode *vp; 74 struct inode *ip; 75 struct uio *uio; 76 FS *fs; 77 struct buf *bp; 78 off_t bytesinfile; 79 int xfersize, blkoffset; 80 int error, orig_resid; 81 u_short mode; 82 int seqcount; 83 int ioflag; 84 85 vp = ap->a_vp; 86 seqcount = ap->a_ioflag >> 16; 87 ip = VTOI(vp); 88 mode = ip->i_mode; 89 uio = ap->a_uio; 90 ioflag = ap->a_ioflag; 91 #ifdef DIRECTIO 92 if ((ioflag & IO_DIRECT) != 0) { 93 int workdone; 94 95 error = ffs_rawread(vp, uio, &workdone); 96 if (error || workdone) 97 return error; 98 } 99 #endif 100 101 #ifdef DIAGNOSTIC 102 if (uio->uio_rw != UIO_READ) 103 panic("ffs_read: mode"); 104 105 if (vp->v_type == VLNK) { 106 if ((int)ip->i_size < vp->v_mount->mnt_maxsymlinklen) 107 panic("ffs_read: short symlink"); 108 } else if (vp->v_type != VREG && vp->v_type != VDIR) 109 panic("ffs_read: type %d", vp->v_type); 110 #endif 111 fs = ip->I_FS; 112 if ((uint64_t)uio->uio_offset > fs->fs_maxfilesize) 113 return (EFBIG); 114 115 orig_resid = uio->uio_resid; 116 if (orig_resid <= 0) 117 return (0); 118 119 bytesinfile = ip->i_size - uio->uio_offset; 120 if (bytesinfile <= 0) { 121 if ((vp->v_mount->mnt_flag & MNT_NOATIME) == 0) 122 ip->i_flag |= IN_ACCESS; 123 return 0; 124 } 125 126 /* 127 * Ok so we couldn't do it all in one vm trick... 128 * so cycle around trying smaller bites.. 129 */ 130 for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { 131 if ((bytesinfile = ip->i_size - uio->uio_offset) <= 0) 132 break; 133 134 error = ffs_blkatoff_ra(vp, uio->uio_offset, NULL, 135 &bp, seqcount); 136 if (error) 137 break; 138 139 /* 140 * If IO_DIRECT then set B_DIRECT for the buffer. This 141 * will cause us to attempt to release the buffer later on 142 * and will cause the buffer cache to attempt to free the 143 * underlying pages. 144 */ 145 if (ioflag & IO_DIRECT) 146 bp->b_flags |= B_DIRECT; 147 148 /* 149 * We should only get non-zero b_resid when an I/O error 150 * has occurred, which should cause us to break above. 151 * However, if the short read did not cause an error, 152 * then we want to ensure that we do not uiomove bad 153 * or uninitialized data. 154 * 155 * XXX b_resid is only valid when an actual I/O has occured 156 * and may be incorrect if the buffer is B_CACHE or if the 157 * last op on the buffer was a failed write. This KASSERT 158 * is a precursor to removing it from the UFS code. 159 */ 160 KASSERT(bp->b_resid == 0, ("bp->b_resid != 0")); 161 162 /* 163 * Calculate how much data we can copy 164 */ 165 blkoffset = blkoff(fs, uio->uio_offset); 166 xfersize = bp->b_bufsize - blkoffset; 167 if (xfersize > uio->uio_resid) 168 xfersize = uio->uio_resid; 169 if (xfersize > bytesinfile) 170 xfersize = bytesinfile; 171 if (xfersize <= 0) { 172 panic("ufs_readwrite: impossible xfersize: %d", 173 xfersize); 174 } 175 176 /* 177 * otherwise use the general form 178 */ 179 error = uiomove(bp->b_data + blkoffset, (int)xfersize, uio); 180 181 if (error) 182 break; 183 184 if ((ioflag & (IO_VMIO|IO_DIRECT)) && 185 (LIST_FIRST(&bp->b_dep) == NULL)) { 186 /* 187 * If there are no dependencies, and it's VMIO, 188 * then we don't need the buf, mark it available 189 * for freeing. The VM has the data. 190 */ 191 bp->b_flags |= B_RELBUF; 192 brelse(bp); 193 } else { 194 /* 195 * Otherwise let whoever 196 * made the request take care of 197 * freeing it. We just queue 198 * it onto another list. 199 */ 200 bqrelse(bp); 201 } 202 } 203 204 /* 205 * This can only happen in the case of an error 206 * because the loop above resets bp to NULL on each iteration 207 * and on normal completion has not set a new value into it. 208 * so it must have come from a 'break' statement 209 */ 210 if (bp != NULL) { 211 if ((ioflag & (IO_VMIO|IO_DIRECT)) && 212 (LIST_FIRST(&bp->b_dep) == NULL)) { 213 bp->b_flags |= B_RELBUF; 214 brelse(bp); 215 } else { 216 bqrelse(bp); 217 } 218 } 219 220 if ((error == 0 || uio->uio_resid != orig_resid) && 221 (vp->v_mount->mnt_flag & MNT_NOATIME) == 0) 222 ip->i_flag |= IN_ACCESS; 223 return (error); 224 } 225 226 /* 227 * Vnode op for writing. 228 * 229 * ffs_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag, 230 * struct ucred *a_cred) 231 */ 232 int 233 ffs_write(struct vop_write_args *ap) 234 { 235 struct vnode *vp; 236 struct uio *uio; 237 struct inode *ip; 238 FS *fs; 239 struct buf *bp; 240 ufs_daddr_t lbn; 241 off_t osize; 242 off_t nsize; 243 int seqcount; 244 int blkoffset, error, extended, flags, ioflag, resid, size, xfersize; 245 struct thread *td; 246 247 extended = 0; 248 seqcount = ap->a_ioflag >> 16; 249 ioflag = ap->a_ioflag; 250 uio = ap->a_uio; 251 vp = ap->a_vp; 252 ip = VTOI(vp); 253 254 #ifdef DIAGNOSTIC 255 if (uio->uio_rw != UIO_WRITE) 256 panic("ffs_write: mode"); 257 #endif 258 259 switch (vp->v_type) { 260 case VREG: 261 if (ioflag & IO_APPEND) 262 uio->uio_offset = ip->i_size; 263 if ((ip->i_flags & APPEND) && uio->uio_offset != ip->i_size) 264 return (EPERM); 265 /* FALLTHROUGH */ 266 case VLNK: 267 break; 268 case VDIR: 269 panic("ffs_write: dir write"); 270 break; 271 default: 272 panic("ffs_write: type %p %d (%d,%d)", vp, (int)vp->v_type, 273 (int)uio->uio_offset, 274 (int)uio->uio_resid 275 ); 276 } 277 278 fs = ip->I_FS; 279 if (uio->uio_offset < 0 || 280 (uint64_t)uio->uio_offset + uio->uio_resid > fs->fs_maxfilesize) { 281 return (EFBIG); 282 } 283 /* 284 * Maybe this should be above the vnode op call, but so long as 285 * file servers have no limits, I don't think it matters. 286 */ 287 td = uio->uio_td; 288 if (vp->v_type == VREG && td && td->td_proc && 289 uio->uio_offset + uio->uio_resid > 290 td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur) { 291 lwpsignal(td->td_proc, td->td_lwp, SIGXFSZ); 292 return (EFBIG); 293 } 294 295 resid = uio->uio_resid; 296 osize = ip->i_size; 297 298 /* 299 * NOTE! These B_ flags are actually balloc-only flags, not buffer 300 * flags. They are similar to the BA_ flags in fbsd. 301 */ 302 if (seqcount > B_SEQMAX) 303 flags = B_SEQMAX << B_SEQSHIFT; 304 else 305 flags = seqcount << B_SEQSHIFT; 306 if ((ioflag & IO_SYNC) && !DOINGASYNC(vp)) 307 flags |= B_SYNC; 308 309 for (error = 0; uio->uio_resid > 0;) { 310 lbn = lblkno(fs, uio->uio_offset); 311 blkoffset = blkoff(fs, uio->uio_offset); 312 xfersize = fs->fs_bsize - blkoffset; 313 if (uio->uio_resid < xfersize) 314 xfersize = uio->uio_resid; 315 316 if (uio->uio_offset + xfersize > ip->i_size) { 317 nsize = uio->uio_offset + xfersize; 318 nvnode_pager_setsize(vp, nsize, 319 blkoffresize(fs, nsize), blkoff(fs, nsize)); 320 } 321 322 #if 0 323 /* 324 * If doing a dummy write to flush the buffer for a 325 * putpages we must perform a read-before-write to 326 * fill in any missing spots and clear any invalid 327 * areas. Otherwise a multi-page buffer may not properly 328 * flush. 329 * 330 * We must clear any invalid areas 331 */ 332 if (uio->uio_segflg == UIO_NOCOPY) { 333 error = ffs_blkatoff(vp, uio->uio_offset, NULL, &bp); 334 if (error) 335 break; 336 bqrelse(bp); 337 } 338 #endif 339 340 /* 341 * We must clear invalid areas. 342 */ 343 if (xfersize < fs->fs_bsize || uio->uio_segflg == UIO_NOCOPY) 344 flags |= B_CLRBUF; 345 else 346 flags &= ~B_CLRBUF; 347 /* XXX is uio->uio_offset the right thing here? */ 348 error = VOP_BALLOC(vp, uio->uio_offset, xfersize, 349 ap->a_cred, flags, &bp); 350 if (error != 0) 351 break; 352 /* 353 * If the buffer is not valid and we did not clear garbage 354 * out above, we have to do so here even though the write 355 * covers the entire buffer in order to avoid a mmap()/write 356 * race where another process may see the garbage prior to 357 * the uiomove() for a write replacing it. 358 */ 359 if ((bp->b_flags & B_CACHE) == 0 && (flags & B_CLRBUF) == 0) 360 vfs_bio_clrbuf(bp); 361 if (ioflag & IO_DIRECT) 362 bp->b_flags |= B_DIRECT; 363 if ((ioflag & (IO_SYNC|IO_INVAL)) == (IO_SYNC|IO_INVAL)) 364 bp->b_flags |= B_NOCACHE; 365 366 if (uio->uio_offset + xfersize > ip->i_size) { 367 ip->i_size = uio->uio_offset + xfersize; 368 extended = 1; 369 } 370 371 size = BLKSIZE(fs, ip, lbn) - bp->b_resid; 372 if (size < xfersize) 373 xfersize = size; 374 375 error = uiomove(bp->b_data + blkoffset, (int)xfersize, uio); 376 if ((ioflag & (IO_VMIO|IO_DIRECT)) && 377 (LIST_FIRST(&bp->b_dep) == NULL)) { 378 bp->b_flags |= B_RELBUF; 379 } 380 381 /* 382 * If IO_SYNC each buffer is written synchronously. Otherwise 383 * if we have a severe page deficiency write the buffer 384 * asynchronously. Otherwise try to cluster, and if that 385 * doesn't do it then either do an async write (if O_DIRECT), 386 * or a delayed write (if not). 387 */ 388 389 if (ioflag & IO_SYNC) { 390 (void)bwrite(bp); 391 } else if (vm_page_count_severe() || 392 buf_dirty_count_severe() || 393 (ioflag & IO_ASYNC)) { 394 bp->b_flags |= B_CLUSTEROK; 395 bawrite(bp); 396 } else if (xfersize + blkoffset == fs->fs_bsize) { 397 if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) { 398 bp->b_flags |= B_CLUSTEROK; 399 cluster_write(bp, (off_t)ip->i_size, fs->fs_bsize, seqcount); 400 } else { 401 bawrite(bp); 402 } 403 } else if (ioflag & IO_DIRECT) { 404 bp->b_flags |= B_CLUSTEROK; 405 bawrite(bp); 406 } else { 407 bp->b_flags |= B_CLUSTEROK; 408 bdwrite(bp); 409 } 410 if (error || xfersize == 0) 411 break; 412 ip->i_flag |= IN_CHANGE | IN_UPDATE; 413 } 414 /* 415 * If we successfully wrote any data, and we are not the superuser 416 * we clear the setuid and setgid bits as a precaution against 417 * tampering. 418 */ 419 if (resid > uio->uio_resid && ap->a_cred && ap->a_cred->cr_uid != 0) 420 ip->i_mode &= ~(ISUID | ISGID); 421 if (resid > uio->uio_resid) 422 VN_KNOTE(vp, NOTE_WRITE | (extended ? NOTE_EXTEND : 0)); 423 if (error) { 424 if (ioflag & IO_UNIT) { 425 (void)ffs_truncate(vp, osize, ioflag & IO_SYNC, 426 ap->a_cred); 427 uio->uio_offset -= resid - uio->uio_resid; 428 uio->uio_resid = resid; 429 } 430 } else if (resid > uio->uio_resid && (ioflag & IO_SYNC)) { 431 error = ffs_update(vp, 1); 432 } 433 434 return (error); 435 } 436 437