1 /*-
2 * Copyright (c) 2000-2003 Tor Egge
3 * 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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/6.4/sys/ufs/ffs/ffs_rawread.c 176541 2008-02-25 09:12:43Z obrien $");
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/fcntl.h>
33 #include <sys/file.h>
34 #include <sys/stat.h>
35 #include <sys/proc.h>
36 #include <sys/limits.h>
37 #include <sys/mount.h>
38 #include <sys/namei.h>
39 #include <sys/vnode.h>
40 #include <sys/conf.h>
41 #include <sys/filio.h>
42 #include <sys/ttycom.h>
43 #include <sys/bio.h>
44 #include <sys/buf.h>
45 #include <ufs/ufs/extattr.h>
46 #include <ufs/ufs/quota.h>
47 #include <ufs/ufs/inode.h>
48 #include <ufs/ufs/ufsmount.h>
49 #include <ufs/ufs/ufs_extern.h>
50 #include <ufs/ffs/fs.h>
51 #include <ufs/ffs/ffs_extern.h>
52
53 #include <vm/vm.h>
54 #include <vm/vm_extern.h>
55 #include <vm/vm_object.h>
56 #include <sys/kernel.h>
57 #include <sys/sysctl.h>
58
59 static int ffs_rawread_readahead(struct vnode *vp,
60 caddr_t udata,
61 off_t offset,
62 size_t len,
63 struct thread *td,
64 struct buf *bp,
65 caddr_t sa);
66 static int ffs_rawread_main(struct vnode *vp,
67 struct uio *uio);
68
69 static int ffs_rawread_sync(struct vnode *vp, struct thread *td);
70
71 int ffs_rawread(struct vnode *vp, struct uio *uio, int *workdone);
72
73 void ffs_rawread_setup(void);
74
75 SYSCTL_DECL(_vfs_ffs);
76
77 static int ffsrawbufcnt = 4;
78 SYSCTL_INT(_vfs_ffs, OID_AUTO, ffsrawbufcnt, CTLFLAG_RD, &ffsrawbufcnt, 0,
79 "Buffers available for raw reads");
80
81 static int allowrawread = 1;
82 SYSCTL_INT(_vfs_ffs, OID_AUTO, allowrawread, CTLFLAG_RW, &allowrawread, 0,
83 "Flag to enable raw reads");
84
85 static int rawreadahead = 1;
86 SYSCTL_INT(_vfs_ffs, OID_AUTO, rawreadahead, CTLFLAG_RW, &rawreadahead, 0,
87 "Flag to enable readahead for long raw reads");
88
89
90 void
91 ffs_rawread_setup(void)
92 {
93 ffsrawbufcnt = (nswbuf > 100 ) ? (nswbuf - (nswbuf >> 4)) : nswbuf - 8;
94 }
95
96
97 static int
98 ffs_rawread_sync(struct vnode *vp, struct thread *td)
99 {
100 int spl;
101 int error;
102 int upgraded;
103 struct bufobj *bo;
104 struct mount *mp;
105
106 /* Check for dirty mmap, pending writes and dirty buffers */
107 spl = splbio();
108 VI_LOCK(vp);
109 bo = &vp->v_bufobj;
110 if (bo->bo_numoutput > 0 ||
111 bo->bo_dirty.bv_cnt > 0 ||
112 (vp->v_iflag & VI_OBJDIRTY) != 0) {
113 splx(spl);
114 VI_UNLOCK(vp);
115
116 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
117 if (VOP_ISLOCKED(vp, td) != LK_EXCLUSIVE)
118 upgraded = 1;
119 else
120 upgraded = 0;
121 VOP_UNLOCK(vp, 0, td);
122 (void) vn_start_write(vp, &mp, V_WAIT);
123 VOP_LOCK(vp, LK_EXCLUSIVE, td);
124 } else if (VOP_ISLOCKED(vp, td) != LK_EXCLUSIVE) {
125 upgraded = 1;
126 /* Upgrade to exclusive lock, this might block */
127 VOP_LOCK(vp, LK_UPGRADE, td);
128 } else
129 upgraded = 0;
130
131
132 VI_LOCK(vp);
133 /* Check if vnode was reclaimed while unlocked. */
134 if ((vp->v_iflag & VI_DOOMED) != 0) {
135 VI_UNLOCK(vp);
136 if (upgraded != 0)
137 VOP_LOCK(vp, LK_DOWNGRADE, td);
138 vn_finished_write(mp);
139 return (EIO);
140 }
141 /* Attempt to msync mmap() regions to clean dirty mmap */
142 if ((vp->v_iflag & VI_OBJDIRTY) != 0) {
143 VI_UNLOCK(vp);
144 if (vp->v_object != NULL) {
145 VM_OBJECT_LOCK(vp->v_object);
146 vm_object_page_clean(vp->v_object, 0, 0, OBJPC_SYNC);
147 VM_OBJECT_UNLOCK(vp->v_object);
148 }
149 VI_LOCK(vp);
150 }
151
152 /* Wait for pending writes to complete */
153 spl = splbio();
154 error = bufobj_wwait(&vp->v_bufobj, 0, 0);
155 if (error != 0) {
156 /* XXX: can't happen with a zero timeout ??? */
157 splx(spl);
158 VI_UNLOCK(vp);
159 if (upgraded != 0)
160 VOP_LOCK(vp, LK_DOWNGRADE, td);
161 vn_finished_write(mp);
162 return (error);
163 }
164 /* Flush dirty buffers */
165 if (bo->bo_dirty.bv_cnt > 0) {
166 splx(spl);
167 VI_UNLOCK(vp);
168 if ((error = ffs_syncvnode(vp, MNT_WAIT)) != 0) {
169 if (upgraded != 0)
170 VOP_LOCK(vp, LK_DOWNGRADE, td);
171 vn_finished_write(mp);
172 return (error);
173 }
174 VI_LOCK(vp);
175 spl = splbio();
176 if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
177 panic("ffs_rawread_sync: dirty bufs");
178 }
179 splx(spl);
180 VI_UNLOCK(vp);
181 if (upgraded != 0)
182 VOP_LOCK(vp, LK_DOWNGRADE, td);
183 vn_finished_write(mp);
184 } else {
185 splx(spl);
186 VI_UNLOCK(vp);
187 }
188 return 0;
189 }
190
191
192 static int
193 ffs_rawread_readahead(struct vnode *vp,
194 caddr_t udata,
195 off_t offset,
196 size_t len,
197 struct thread *td,
198 struct buf *bp,
199 caddr_t sa)
200 {
201 int error;
202 u_int iolen;
203 off_t blockno;
204 int blockoff;
205 int bsize;
206 struct vnode *dp;
207 int bforwards;
208 struct inode *ip;
209 ufs2_daddr_t blkno;
210
211 bsize = vp->v_mount->mnt_stat.f_iosize;
212
213 ip = VTOI(vp);
214 dp = ip->i_devvp;
215
216 iolen = ((vm_offset_t) udata) & PAGE_MASK;
217 bp->b_bcount = len;
218 if (bp->b_bcount + iolen > bp->b_kvasize) {
219 bp->b_bcount = bp->b_kvasize;
220 if (iolen != 0)
221 bp->b_bcount -= PAGE_SIZE;
222 }
223 bp->b_flags = 0; /* XXX necessary ? */
224 bp->b_iocmd = BIO_READ;
225 bp->b_iodone = bdone;
226 bp->b_data = udata;
227 bp->b_saveaddr = sa;
228 blockno = offset / bsize;
229 blockoff = (offset % bsize) / DEV_BSIZE;
230 if ((daddr_t) blockno != blockno) {
231 return EINVAL; /* blockno overflow */
232 }
233
234 bp->b_lblkno = bp->b_blkno = blockno;
235
236 error = ufs_bmaparray(vp, bp->b_lblkno, &blkno, NULL, &bforwards, NULL);
237 if (error != 0)
238 return error;
239 if (blkno == -1) {
240
241 /* Fill holes with NULs to preserve semantics */
242
243 if (bp->b_bcount + blockoff * DEV_BSIZE > bsize)
244 bp->b_bcount = bsize - blockoff * DEV_BSIZE;
245 bp->b_bufsize = bp->b_bcount;
246
247 if (vmapbuf(bp) < 0)
248 return EFAULT;
249
250 if (ticks - PCPU_GET(switchticks) >= hogticks)
251 uio_yield();
252 bzero(bp->b_data, bp->b_bufsize);
253
254 /* Mark operation completed (similar to bufdone()) */
255
256 bp->b_resid = 0;
257 bp->b_flags |= B_DONE;
258 return 0;
259 }
260 bp->b_blkno = blkno + blockoff;
261 bp->b_offset = bp->b_iooffset = (blkno + blockoff) * DEV_BSIZE;
262
263 if (bp->b_bcount + blockoff * DEV_BSIZE > bsize * (1 + bforwards))
264 bp->b_bcount = bsize * (1 + bforwards) - blockoff * DEV_BSIZE;
265 bp->b_bufsize = bp->b_bcount;
266
267 if (vmapbuf(bp) < 0)
268 return EFAULT;
269
270 BO_STRATEGY(&dp->v_bufobj, bp);
271 return 0;
272 }
273
274
275 static int
276 ffs_rawread_main(struct vnode *vp,
277 struct uio *uio)
278 {
279 int error, nerror;
280 struct buf *bp, *nbp, *tbp;
281 caddr_t sa, nsa, tsa;
282 u_int iolen;
283 int spl;
284 caddr_t udata;
285 long resid;
286 off_t offset;
287 struct thread *td;
288
289 td = uio->uio_td ? uio->uio_td : curthread;
290 udata = uio->uio_iov->iov_base;
291 resid = uio->uio_resid;
292 offset = uio->uio_offset;
293
294 /*
295 * keep the process from being swapped
296 */
297 PHOLD(td->td_proc);
298
299 error = 0;
300 nerror = 0;
301
302 bp = NULL;
303 nbp = NULL;
304 sa = NULL;
305 nsa = NULL;
306
307 while (resid > 0) {
308
309 if (bp == NULL) { /* Setup first read */
310 /* XXX: Leave some bufs for swap */
311 bp = getpbuf(&ffsrawbufcnt);
312 sa = bp->b_data;
313 pbgetvp(vp, bp);
314 error = ffs_rawread_readahead(vp, udata, offset,
315 resid, td, bp, sa);
316 if (error != 0)
317 break;
318
319 if (resid > bp->b_bufsize) { /* Setup fist readahead */
320 /* XXX: Leave bufs for swap */
321 if (rawreadahead != 0)
322 nbp = trypbuf(&ffsrawbufcnt);
323 else
324 nbp = NULL;
325 if (nbp != NULL) {
326 nsa = nbp->b_data;
327 pbgetvp(vp, nbp);
328
329 nerror = ffs_rawread_readahead(vp,
330 udata +
331 bp->b_bufsize,
332 offset +
333 bp->b_bufsize,
334 resid -
335 bp->b_bufsize,
336 td,
337 nbp,
338 nsa);
339 if (nerror) {
340 pbrelvp(nbp);
341 relpbuf(nbp, &ffsrawbufcnt);
342 nbp = NULL;
343 }
344 }
345 }
346 }
347
348 spl = splbio();
349 bwait(bp, PRIBIO, "rawrd");
350 splx(spl);
351
352 vunmapbuf(bp);
353
354 iolen = bp->b_bcount - bp->b_resid;
355 if (iolen == 0 && (bp->b_ioflags & BIO_ERROR) == 0) {
356 nerror = 0; /* Ignore possible beyond EOF error */
357 break; /* EOF */
358 }
359
360 if ((bp->b_ioflags & BIO_ERROR) != 0) {
361 error = bp->b_error;
362 break;
363 }
364 resid -= iolen;
365 udata += iolen;
366 offset += iolen;
367 if (iolen < bp->b_bufsize) {
368 /* Incomplete read. Try to read remaining part */
369 error = ffs_rawread_readahead(vp,
370 udata,
371 offset,
372 bp->b_bufsize - iolen,
373 td,
374 bp,
375 sa);
376 if (error != 0)
377 break;
378 } else if (nbp != NULL) { /* Complete read with readahead */
379
380 tbp = bp;
381 bp = nbp;
382 nbp = tbp;
383
384 tsa = sa;
385 sa = nsa;
386 nsa = tsa;
387
388 if (resid <= bp->b_bufsize) { /* No more readaheads */
389 pbrelvp(nbp);
390 relpbuf(nbp, &ffsrawbufcnt);
391 nbp = NULL;
392 } else { /* Setup next readahead */
393 nerror = ffs_rawread_readahead(vp,
394 udata +
395 bp->b_bufsize,
396 offset +
397 bp->b_bufsize,
398 resid -
399 bp->b_bufsize,
400 td,
401 nbp,
402 nsa);
403 if (nerror != 0) {
404 pbrelvp(nbp);
405 relpbuf(nbp, &ffsrawbufcnt);
406 nbp = NULL;
407 }
408 }
409 } else if (nerror != 0) {/* Deferred Readahead error */
410 break;
411 } else if (resid > 0) { /* More to read, no readahead */
412 error = ffs_rawread_readahead(vp, udata, offset,
413 resid, td, bp, sa);
414 if (error != 0)
415 break;
416 }
417 }
418
419 if (bp != NULL) {
420 pbrelvp(bp);
421 relpbuf(bp, &ffsrawbufcnt);
422 }
423 if (nbp != NULL) { /* Run down readahead buffer */
424 spl = splbio();
425 bwait(nbp, PRIBIO, "rawrd");
426 splx(spl);
427 vunmapbuf(nbp);
428 pbrelvp(nbp);
429 relpbuf(nbp, &ffsrawbufcnt);
430 }
431
432 if (error == 0)
433 error = nerror;
434 PRELE(td->td_proc);
435 uio->uio_iov->iov_base = udata;
436 uio->uio_resid = resid;
437 uio->uio_offset = offset;
438 return error;
439 }
440
441
442 int
443 ffs_rawread(struct vnode *vp,
444 struct uio *uio,
445 int *workdone)
446 {
447 if (allowrawread != 0 &&
448 uio->uio_iovcnt == 1 &&
449 uio->uio_segflg == UIO_USERSPACE &&
450 uio->uio_resid == uio->uio_iov->iov_len &&
451 (((uio->uio_td != NULL) ? uio->uio_td : curthread)->td_pflags &
452 TDP_DEADLKTREAT) == 0) {
453 int secsize; /* Media sector size */
454 off_t filebytes; /* Bytes left of file */
455 int blockbytes; /* Bytes left of file in full blocks */
456 int partialbytes; /* Bytes in last partial block */
457 int skipbytes; /* Bytes not to read in ffs_rawread */
458 struct inode *ip;
459 int error;
460
461
462 /* Only handle sector aligned reads */
463 ip = VTOI(vp);
464 secsize = ip->i_devvp->v_bufobj.bo_bsize;
465 if ((uio->uio_offset & (secsize - 1)) == 0 &&
466 (uio->uio_resid & (secsize - 1)) == 0) {
467
468 /* Sync dirty pages and buffers if needed */
469 error = ffs_rawread_sync(vp,
470 (uio->uio_td != NULL) ?
471 uio->uio_td : curthread);
472 if (error != 0)
473 return error;
474
475 /* Check for end of file */
476 if (ip->i_size > uio->uio_offset) {
477 filebytes = ip->i_size - uio->uio_offset;
478
479 /* No special eof handling needed ? */
480 if (uio->uio_resid <= filebytes) {
481 *workdone = 1;
482 return ffs_rawread_main(vp, uio);
483 }
484
485 partialbytes = ((unsigned int) ip->i_size) %
486 ip->i_fs->fs_bsize;
487 blockbytes = (int) filebytes - partialbytes;
488 if (blockbytes > 0) {
489 skipbytes = uio->uio_resid -
490 blockbytes;
491 uio->uio_resid = blockbytes;
492 error = ffs_rawread_main(vp, uio);
493 uio->uio_resid += skipbytes;
494 if (error != 0)
495 return error;
496 /* Read remaining part using buffer */
497 }
498 }
499 }
500 }
501 *workdone = 0;
502 return 0;
503 }
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