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. 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 * @(#)ufs_readwrite.c 8.11 (Berkeley) 5/8/95 30 * $FreeBSD: src/sys/ufs/ufs/ufs_readwrite.c,v 1.65.2.14 2003/04/04 22:21:29 tegge Exp $ 31 */ 32 33 #define BLKSIZE(a, b, c) blksize(a, b, c) 34 #define FS struct fs 35 #define I_FS i_fs 36 37 #include <vm/vm.h> 38 #include <vm/vm_object.h> 39 #include <vm/vm_pager.h> 40 #include <vm/vm_map.h> 41 #include <vm/vnode_pager.h> 42 #include <sys/event.h> 43 #include <sys/vmmeter.h> 44 #include <sys/sysctl.h> 45 #include <vm/vm_page2.h> 46 47 #define VN_KNOTE(vp, b) KNOTE(&vp->v_pollinfo.vpi_kqinfo.ki_note, (b)) 48 49 SYSCTL_DECL(_vfs_ffs); 50 51 /* 52 * Vnode op for reading. 53 * 54 * ffs_read(struct vnode *a_vp, struct uio *a_uio, int a_ioflag, 55 * struct ucred *a_cred) 56 */ 57 /* ARGSUSED */ 58 int 59 ffs_read(struct vop_read_args *ap) 60 { 61 struct vnode *vp; 62 struct inode *ip; 63 struct uio *uio; 64 FS *fs; 65 struct buf *bp; 66 off_t bytesinfile; 67 int xfersize, blkoffset; 68 int error, orig_resid; 69 int seqcount; 70 int ioflag; 71 72 vp = ap->a_vp; 73 seqcount = ap->a_ioflag >> IO_SEQSHIFT; 74 ip = VTOI(vp); 75 uio = ap->a_uio; 76 ioflag = ap->a_ioflag; 77 #ifdef DIAGNOSTIC 78 if (uio->uio_rw != UIO_READ) 79 panic("ffs_read: mode"); 80 81 if (vp->v_type == VLNK) { 82 if ((int)ip->i_size < vp->v_mount->mnt_maxsymlinklen) 83 panic("ffs_read: short symlink"); 84 } else if (vp->v_type != VREG && vp->v_type != VDIR) 85 panic("ffs_read: type %d", vp->v_type); 86 #endif 87 fs = ip->I_FS; 88 if ((uint64_t)uio->uio_offset > fs->fs_maxfilesize) 89 return (EFBIG); 90 91 orig_resid = uio->uio_resid; 92 if (orig_resid <= 0) 93 return (0); 94 95 bytesinfile = ip->i_size - uio->uio_offset; 96 if (bytesinfile <= 0) { 97 if ((vp->v_mount->mnt_flag & MNT_NOATIME) == 0) 98 ip->i_flag |= IN_ACCESS; 99 return 0; 100 } 101 102 /* 103 * Ok so we couldn't do it all in one vm trick... 104 * so cycle around trying smaller bites.. 105 */ 106 for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) { 107 if ((bytesinfile = ip->i_size - uio->uio_offset) <= 0) 108 break; 109 110 error = ffs_blkatoff_ra(vp, uio->uio_offset, NULL, 111 &bp, seqcount); 112 if (error) 113 break; 114 115 /* 116 * If IO_DIRECT then set B_DIRECT for the buffer. This 117 * will cause us to attempt to release the buffer later on 118 * and will cause the buffer cache to attempt to free the 119 * underlying pages. 120 */ 121 if (ioflag & IO_DIRECT) 122 bp->b_flags |= B_DIRECT; 123 124 /* 125 * We should only get non-zero b_resid when an I/O error 126 * has occurred, which should cause us to break above. 127 * However, if the short read did not cause an error, 128 * then we want to ensure that we do not uiomove bad 129 * or uninitialized data. 130 * 131 * XXX b_resid is only valid when an actual I/O has occured 132 * and may be incorrect if the buffer is B_CACHE or if the 133 * last op on the buffer was a failed write. This KASSERT 134 * is a precursor to removing it from the UFS code. 135 */ 136 KASSERT(bp->b_resid == 0, ("bp->b_resid != 0")); 137 138 /* 139 * Calculate how much data we can copy 140 */ 141 blkoffset = blkoff(fs, uio->uio_offset); 142 xfersize = bp->b_bufsize - blkoffset; 143 if (xfersize > uio->uio_resid) 144 xfersize = uio->uio_resid; 145 if (xfersize > bytesinfile) 146 xfersize = bytesinfile; 147 if (xfersize <= 0) { 148 panic("ufs_readwrite: impossible xfersize: %d", 149 xfersize); 150 } 151 152 /* 153 * otherwise use the general form 154 */ 155 error = uiomovebp(bp, bp->b_data + blkoffset, xfersize, uio); 156 157 if (error) 158 break; 159 160 if ((ioflag & (IO_VMIO|IO_DIRECT)) && 161 (LIST_FIRST(&bp->b_dep) == NULL)) { 162 /* 163 * If there are no dependencies, and it's VMIO, 164 * then we don't need the buf, mark it available 165 * for freeing. The VM has the data. 166 */ 167 bp->b_flags |= B_RELBUF; 168 brelse(bp); 169 } else { 170 /* 171 * Otherwise let whoever 172 * made the request take care of 173 * freeing it. We just queue 174 * it onto another list. 175 */ 176 bqrelse(bp); 177 } 178 } 179 180 /* 181 * This can only happen in the case of an error 182 * because the loop above resets bp to NULL on each iteration 183 * and on normal completion has not set a new value into it. 184 * so it must have come from a 'break' statement 185 */ 186 if (bp != NULL) { 187 if ((ioflag & (IO_VMIO|IO_DIRECT)) && 188 (LIST_FIRST(&bp->b_dep) == NULL)) { 189 bp->b_flags |= B_RELBUF; 190 brelse(bp); 191 } else { 192 bqrelse(bp); 193 } 194 } 195 196 if ((error == 0 || uio->uio_resid != orig_resid) && 197 (vp->v_mount->mnt_flag & MNT_NOATIME) == 0) 198 ip->i_flag |= IN_ACCESS; 199 return (error); 200 } 201 202 /* 203 * Vnode op for writing. 204 * 205 * ffs_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag, 206 * struct ucred *a_cred) 207 */ 208 int 209 ffs_write(struct vop_write_args *ap) 210 { 211 struct vnode *vp; 212 struct uio *uio; 213 struct inode *ip; 214 FS *fs; 215 struct buf *bp; 216 ufs_daddr_t lbn; 217 off_t osize; 218 off_t nsize; 219 int seqcount; 220 int blkoffset, error, extended, flags, ioflag, resid, size, xfersize; 221 struct thread *td; 222 223 extended = 0; 224 seqcount = ap->a_ioflag >> IO_SEQSHIFT; 225 ioflag = ap->a_ioflag; 226 uio = ap->a_uio; 227 vp = ap->a_vp; 228 ip = VTOI(vp); 229 230 #ifdef DIAGNOSTIC 231 if (uio->uio_rw != UIO_WRITE) 232 panic("ffs_write: mode"); 233 #endif 234 235 switch (vp->v_type) { 236 case VREG: 237 if (ioflag & IO_APPEND) 238 uio->uio_offset = ip->i_size; 239 if ((ip->i_flags & APPEND) && uio->uio_offset != ip->i_size) 240 return (EPERM); 241 /* FALLTHROUGH */ 242 case VLNK: 243 break; 244 case VDIR: 245 panic("ffs_write: dir write"); 246 break; 247 default: 248 panic("ffs_write: type %p %d (%d,%d)", vp, (int)vp->v_type, 249 (int)uio->uio_offset, 250 (int)uio->uio_resid 251 ); 252 } 253 254 fs = ip->I_FS; 255 if (uio->uio_offset < 0 || 256 (uint64_t)uio->uio_offset + uio->uio_resid > fs->fs_maxfilesize) { 257 return (EFBIG); 258 } 259 /* 260 * Maybe this should be above the vnode op call, but so long as 261 * file servers have no limits, I don't think it matters. 262 */ 263 td = uio->uio_td; 264 if (vp->v_type == VREG && td && td->td_proc && 265 uio->uio_offset + uio->uio_resid > 266 td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur) { 267 lwpsignal(td->td_proc, td->td_lwp, SIGXFSZ); 268 return (EFBIG); 269 } 270 271 resid = uio->uio_resid; 272 osize = ip->i_size; 273 274 /* 275 * NOTE! These B_ flags are actually balloc-only flags, not buffer 276 * flags. They are similar to the BA_ flags in fbsd. 277 */ 278 if (seqcount > B_SEQMAX) 279 flags = B_SEQMAX << B_SEQSHIFT; 280 else 281 flags = seqcount << B_SEQSHIFT; 282 if ((ioflag & IO_SYNC) && !DOINGASYNC(vp)) 283 flags |= B_SYNC; 284 285 if (uio->uio_segflg == UIO_NOCOPY) 286 ip->i_flag |= IN_NOCOPYWRITE; 287 else 288 vclrflags(vp, VLASTWRITETS); 289 290 for (error = 0; uio->uio_resid > 0;) { 291 lbn = lblkno(fs, uio->uio_offset); 292 blkoffset = blkoff(fs, uio->uio_offset); 293 xfersize = fs->fs_bsize - blkoffset; 294 if (uio->uio_resid < xfersize) 295 xfersize = uio->uio_resid; 296 297 if (uio->uio_offset + xfersize > ip->i_size) { 298 nsize = uio->uio_offset + xfersize; 299 nvnode_pager_setsize(vp, nsize, 300 blkoffresize(fs, nsize), blkoff(fs, nsize)); 301 } 302 303 #if 0 304 /* 305 * If doing a dummy write to flush the buffer for a 306 * putpages we must perform a read-before-write to 307 * fill in any missing spots and clear any invalid 308 * areas. Otherwise a multi-page buffer may not properly 309 * flush. 310 * 311 * We must clear any invalid areas 312 */ 313 if (uio->uio_segflg == UIO_NOCOPY) { 314 error = ffs_blkatoff(vp, uio->uio_offset, NULL, &bp); 315 if (error) 316 break; 317 bqrelse(bp); 318 } 319 #endif 320 321 /* 322 * We must clear invalid areas. 323 */ 324 if (xfersize < fs->fs_bsize || uio->uio_segflg == UIO_NOCOPY) 325 flags |= B_CLRBUF; 326 else 327 flags &= ~B_CLRBUF; 328 /* XXX is uio->uio_offset the right thing here? */ 329 error = VOP_BALLOC(vp, uio->uio_offset, xfersize, 330 ap->a_cred, flags, &bp); 331 if (error != 0) 332 break; 333 /* 334 * If the buffer is not valid and we did not clear garbage 335 * out above, we have to do so here even though the write 336 * covers the entire buffer in order to avoid a mmap()/write 337 * race where another process may see the garbage prior to 338 * the uiomove() for a write replacing it. 339 */ 340 if ((bp->b_flags & B_CACHE) == 0 && (flags & B_CLRBUF) == 0) 341 vfs_bio_clrbuf(bp); 342 if (ioflag & IO_DIRECT) 343 bp->b_flags |= B_DIRECT; 344 if ((ioflag & (IO_SYNC|IO_INVAL)) == (IO_SYNC|IO_INVAL)) 345 bp->b_flags |= B_NOCACHE; 346 347 if (uio->uio_offset + xfersize > ip->i_size) { 348 ip->i_size = uio->uio_offset + xfersize; 349 extended = 1; 350 } 351 352 size = BLKSIZE(fs, ip, lbn) - bp->b_resid; 353 if (size < xfersize) 354 xfersize = size; 355 356 error = uiomovebp(bp, bp->b_data + blkoffset, xfersize, uio); 357 if ((ioflag & (IO_VMIO|IO_DIRECT)) && 358 (LIST_FIRST(&bp->b_dep) == NULL)) { 359 bp->b_flags |= B_RELBUF; 360 } 361 362 /* 363 * If IO_SYNC each buffer is written synchronously. Otherwise 364 * if we have a severe page deficiency write the buffer 365 * asynchronously. Otherwise try to cluster, and if that 366 * doesn't do it then either do an async write (if O_DIRECT), 367 * or a delayed write (if not). 368 */ 369 370 if (ioflag & IO_SYNC) { 371 (void)bwrite(bp); 372 } else if (vm_paging_severe() || 373 buf_dirty_count_severe() || 374 (ioflag & IO_ASYNC)) { 375 bp->b_flags |= B_CLUSTEROK; 376 bawrite(bp); 377 } else if (xfersize + blkoffset == fs->fs_bsize) { 378 if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) { 379 bp->b_flags |= B_CLUSTEROK; 380 cluster_write(bp, (off_t)ip->i_size, fs->fs_bsize, seqcount); 381 } else { 382 bawrite(bp); 383 } 384 } else if (ioflag & IO_DIRECT) { 385 bp->b_flags |= B_CLUSTEROK; 386 bawrite(bp); 387 } else { 388 bp->b_flags |= B_CLUSTEROK; 389 bdwrite(bp); 390 } 391 if (error || xfersize == 0) 392 break; 393 ip->i_flag |= IN_CHANGE | IN_UPDATE; 394 } 395 /* 396 * If we successfully wrote any data, and we are not the superuser 397 * we clear the setuid and setgid bits as a precaution against 398 * tampering. 399 */ 400 if (resid > uio->uio_resid && ap->a_cred && ap->a_cred->cr_uid != 0) 401 ip->i_mode &= ~(ISUID | ISGID); 402 if (resid > uio->uio_resid) 403 VN_KNOTE(vp, NOTE_WRITE | (extended ? NOTE_EXTEND : 0)); 404 if (error) { 405 if (ioflag & IO_UNIT) { 406 (void)ffs_truncate(vp, osize, ioflag & IO_SYNC, 407 ap->a_cred); 408 uio->uio_offset -= resid - uio->uio_resid; 409 uio->uio_resid = resid; 410 } 411 } else if (resid > uio->uio_resid && (ioflag & IO_SYNC)) { 412 error = ffs_update(vp, 1); 413 } else { 414 ufs_itimes(vp); 415 } 416 if (uio->uio_segflg == UIO_NOCOPY) 417 ip->i_flag &= ~IN_NOCOPYWRITE; 418 419 return (error); 420 } 421 422