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