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