1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2000-2003 Tor Egge
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/fcntl.h>
35 #include <sys/file.h>
36 #include <sys/stat.h>
37 #include <sys/proc.h>
38 #include <sys/limits.h>
39 #include <sys/mount.h>
40 #include <sys/namei.h>
41 #include <sys/vnode.h>
42 #include <sys/conf.h>
43 #include <sys/filio.h>
44 #include <sys/ttycom.h>
45 #include <sys/bio.h>
46 #include <sys/buf.h>
47 #include <sys/rwlock.h>
48 #include <ufs/ufs/extattr.h>
49 #include <ufs/ufs/quota.h>
50 #include <ufs/ufs/inode.h>
51 #include <ufs/ufs/ufsmount.h>
52 #include <ufs/ufs/ufs_extern.h>
53 #include <ufs/ffs/fs.h>
54 #include <ufs/ffs/ffs_extern.h>
55
56 #include <vm/vm.h>
57 #include <vm/vm_extern.h>
58 #include <vm/vm_object.h>
59 #include <sys/kernel.h>
60 #include <sys/sysctl.h>
61
62 static int ffs_rawread_readahead(struct vnode *vp,
63 caddr_t udata,
64 off_t offset,
65 size_t len,
66 struct thread *td,
67 struct buf *bp);
68 static int ffs_rawread_main(struct vnode *vp,
69 struct uio *uio);
70
71 static int ffs_rawread_sync(struct vnode *vp);
72
73 int ffs_rawread(struct vnode *vp, struct uio *uio, int *workdone);
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 static void
ffs_rawread_setup(void * arg __unused)90 ffs_rawread_setup(void *arg __unused)
91 {
92
93 ffsrawbufcnt = (nswbuf > 100 ) ? (nswbuf - (nswbuf >> 4)) : nswbuf - 8;
94 }
95 SYSINIT(ffs_raw, SI_SUB_VM_CONF, SI_ORDER_ANY, ffs_rawread_setup, NULL);
96
97 static int
ffs_rawread_sync(struct vnode * vp)98 ffs_rawread_sync(struct vnode *vp)
99 {
100 int error;
101 int upgraded;
102 struct bufobj *bo;
103 struct mount *mp;
104 vm_object_t obj;
105
106 /* Check for dirty mmap, pending writes and dirty buffers */
107 bo = &vp->v_bufobj;
108 BO_LOCK(bo);
109 VI_LOCK(vp);
110 if (bo->bo_numoutput > 0 ||
111 bo->bo_dirty.bv_cnt > 0 ||
112 ((obj = vp->v_object) != NULL &&
113 (obj->flags & OBJ_MIGHTBEDIRTY) != 0)) {
114 VI_UNLOCK(vp);
115 BO_UNLOCK(bo);
116
117 if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
118 if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
119 upgraded = 1;
120 else
121 upgraded = 0;
122 VOP_UNLOCK(vp, 0);
123 (void) vn_start_write(vp, &mp, V_WAIT);
124 VOP_LOCK(vp, LK_EXCLUSIVE);
125 } else if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
126 upgraded = 1;
127 /* Upgrade to exclusive lock, this might block */
128 VOP_LOCK(vp, LK_UPGRADE);
129 } else
130 upgraded = 0;
131
132
133 VI_LOCK(vp);
134 /* Check if vnode was reclaimed while unlocked. */
135 if ((vp->v_iflag & VI_DOOMED) != 0) {
136 VI_UNLOCK(vp);
137 if (upgraded != 0)
138 VOP_LOCK(vp, LK_DOWNGRADE);
139 vn_finished_write(mp);
140 return (EIO);
141 }
142 /* Attempt to msync mmap() regions to clean dirty mmap */
143 if ((obj = vp->v_object) != NULL &&
144 (obj->flags & OBJ_MIGHTBEDIRTY) != 0) {
145 VI_UNLOCK(vp);
146 VM_OBJECT_WLOCK(obj);
147 vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
148 VM_OBJECT_WUNLOCK(obj);
149 } else
150 VI_UNLOCK(vp);
151
152 /* Wait for pending writes to complete */
153 BO_LOCK(bo);
154 error = bufobj_wwait(&vp->v_bufobj, 0, 0);
155 if (error != 0) {
156 /* XXX: can't happen with a zero timeout ??? */
157 BO_UNLOCK(bo);
158 if (upgraded != 0)
159 VOP_LOCK(vp, LK_DOWNGRADE);
160 vn_finished_write(mp);
161 return (error);
162 }
163 /* Flush dirty buffers */
164 if (bo->bo_dirty.bv_cnt > 0) {
165 BO_UNLOCK(bo);
166 if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0) {
167 if (upgraded != 0)
168 VOP_LOCK(vp, LK_DOWNGRADE);
169 vn_finished_write(mp);
170 return (error);
171 }
172 BO_LOCK(bo);
173 if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
174 panic("ffs_rawread_sync: dirty bufs");
175 }
176 BO_UNLOCK(bo);
177 if (upgraded != 0)
178 VOP_LOCK(vp, LK_DOWNGRADE);
179 vn_finished_write(mp);
180 } else {
181 VI_UNLOCK(vp);
182 BO_UNLOCK(bo);
183 }
184 return 0;
185 }
186
187
188 static int
ffs_rawread_readahead(struct vnode * vp,caddr_t udata,off_t offset,size_t len,struct thread * td,struct buf * bp)189 ffs_rawread_readahead(struct vnode *vp,
190 caddr_t udata,
191 off_t offset,
192 size_t len,
193 struct thread *td,
194 struct buf *bp)
195 {
196 int error;
197 u_int iolen;
198 off_t blockno;
199 int blockoff;
200 int bsize;
201 struct vnode *dp;
202 int bforwards;
203 struct inode *ip;
204 ufs2_daddr_t blkno;
205
206 bsize = vp->v_mount->mnt_stat.f_iosize;
207
208 ip = VTOI(vp);
209 dp = ITODEVVP(ip);
210
211 iolen = ((vm_offset_t) udata) & PAGE_MASK;
212 bp->b_bcount = len;
213 if (bp->b_bcount + iolen > bp->b_kvasize) {
214 bp->b_bcount = bp->b_kvasize;
215 if (iolen != 0)
216 bp->b_bcount -= PAGE_SIZE;
217 }
218 bp->b_flags = 0; /* XXX necessary ? */
219 bp->b_iocmd = BIO_READ;
220 bp->b_iodone = bdone;
221 bp->b_data = udata;
222 blockno = offset / bsize;
223 blockoff = (offset % bsize) / DEV_BSIZE;
224 if ((daddr_t) blockno != blockno) {
225 return EINVAL; /* blockno overflow */
226 }
227
228 bp->b_lblkno = bp->b_blkno = blockno;
229
230 error = ufs_bmaparray(vp, bp->b_lblkno, &blkno, NULL, &bforwards, NULL);
231 if (error != 0)
232 return error;
233 if (blkno == -1) {
234
235 /* Fill holes with NULs to preserve semantics */
236
237 if (bp->b_bcount + blockoff * DEV_BSIZE > bsize)
238 bp->b_bcount = bsize - blockoff * DEV_BSIZE;
239 bp->b_bufsize = bp->b_bcount;
240
241 if (vmapbuf(bp, 1) < 0)
242 return EFAULT;
243
244 maybe_yield();
245 bzero(bp->b_data, bp->b_bufsize);
246
247 /* Mark operation completed (similar to bufdone()) */
248
249 bp->b_resid = 0;
250 bp->b_flags |= B_DONE;
251 return 0;
252 }
253 bp->b_blkno = blkno + blockoff;
254 bp->b_offset = bp->b_iooffset = (blkno + blockoff) * DEV_BSIZE;
255
256 if (bp->b_bcount + blockoff * DEV_BSIZE > bsize * (1 + bforwards))
257 bp->b_bcount = bsize * (1 + bforwards) - blockoff * DEV_BSIZE;
258 bp->b_bufsize = bp->b_bcount;
259
260 if (vmapbuf(bp, 1) < 0)
261 return EFAULT;
262
263 BO_STRATEGY(&dp->v_bufobj, bp);
264 return 0;
265 }
266
267
268 static int
ffs_rawread_main(struct vnode * vp,struct uio * uio)269 ffs_rawread_main(struct vnode *vp,
270 struct uio *uio)
271 {
272 int error, nerror;
273 struct buf *bp, *nbp, *tbp;
274 u_int iolen;
275 caddr_t udata;
276 long resid;
277 off_t offset;
278 struct thread *td;
279
280 td = uio->uio_td ? uio->uio_td : curthread;
281 udata = uio->uio_iov->iov_base;
282 resid = uio->uio_resid;
283 offset = uio->uio_offset;
284
285 /*
286 * keep the process from being swapped
287 */
288 PHOLD(td->td_proc);
289
290 error = 0;
291 nerror = 0;
292
293 bp = NULL;
294 nbp = NULL;
295
296 while (resid > 0) {
297
298 if (bp == NULL) { /* Setup first read */
299 /* XXX: Leave some bufs for swap */
300 bp = getpbuf(&ffsrawbufcnt);
301 pbgetvp(vp, bp);
302 error = ffs_rawread_readahead(vp, udata, offset,
303 resid, td, bp);
304 if (error != 0)
305 break;
306
307 if (resid > bp->b_bufsize) { /* Setup fist readahead */
308 /* XXX: Leave bufs for swap */
309 if (rawreadahead != 0)
310 nbp = trypbuf(&ffsrawbufcnt);
311 else
312 nbp = NULL;
313 if (nbp != NULL) {
314 pbgetvp(vp, nbp);
315
316 nerror = ffs_rawread_readahead(vp,
317 udata +
318 bp->b_bufsize,
319 offset +
320 bp->b_bufsize,
321 resid -
322 bp->b_bufsize,
323 td,
324 nbp);
325 if (nerror) {
326 pbrelvp(nbp);
327 relpbuf(nbp, &ffsrawbufcnt);
328 nbp = NULL;
329 }
330 }
331 }
332 }
333
334 bwait(bp, PRIBIO, "rawrd");
335 vunmapbuf(bp);
336
337 iolen = bp->b_bcount - bp->b_resid;
338 if (iolen == 0 && (bp->b_ioflags & BIO_ERROR) == 0) {
339 nerror = 0; /* Ignore possible beyond EOF error */
340 break; /* EOF */
341 }
342
343 if ((bp->b_ioflags & BIO_ERROR) != 0) {
344 error = bp->b_error;
345 break;
346 }
347 resid -= iolen;
348 udata += iolen;
349 offset += iolen;
350 if (iolen < bp->b_bufsize) {
351 /* Incomplete read. Try to read remaining part */
352 error = ffs_rawread_readahead(vp,
353 udata,
354 offset,
355 bp->b_bufsize - iolen,
356 td,
357 bp);
358 if (error != 0)
359 break;
360 } else if (nbp != NULL) { /* Complete read with readahead */
361
362 tbp = bp;
363 bp = nbp;
364 nbp = tbp;
365
366 if (resid <= bp->b_bufsize) { /* No more readaheads */
367 pbrelvp(nbp);
368 relpbuf(nbp, &ffsrawbufcnt);
369 nbp = NULL;
370 } else { /* Setup next readahead */
371 nerror = ffs_rawread_readahead(vp,
372 udata +
373 bp->b_bufsize,
374 offset +
375 bp->b_bufsize,
376 resid -
377 bp->b_bufsize,
378 td,
379 nbp);
380 if (nerror != 0) {
381 pbrelvp(nbp);
382 relpbuf(nbp, &ffsrawbufcnt);
383 nbp = NULL;
384 }
385 }
386 } else if (nerror != 0) {/* Deferred Readahead error */
387 break;
388 } else if (resid > 0) { /* More to read, no readahead */
389 error = ffs_rawread_readahead(vp, udata, offset,
390 resid, td, bp);
391 if (error != 0)
392 break;
393 }
394 }
395
396 if (bp != NULL) {
397 pbrelvp(bp);
398 relpbuf(bp, &ffsrawbufcnt);
399 }
400 if (nbp != NULL) { /* Run down readahead buffer */
401 bwait(nbp, PRIBIO, "rawrd");
402 vunmapbuf(nbp);
403 pbrelvp(nbp);
404 relpbuf(nbp, &ffsrawbufcnt);
405 }
406
407 if (error == 0)
408 error = nerror;
409 PRELE(td->td_proc);
410 uio->uio_iov->iov_base = udata;
411 uio->uio_resid = resid;
412 uio->uio_offset = offset;
413 return error;
414 }
415
416
417 int
ffs_rawread(struct vnode * vp,struct uio * uio,int * workdone)418 ffs_rawread(struct vnode *vp,
419 struct uio *uio,
420 int *workdone)
421 {
422 if (allowrawread != 0 &&
423 uio->uio_iovcnt == 1 &&
424 uio->uio_segflg == UIO_USERSPACE &&
425 uio->uio_resid == uio->uio_iov->iov_len &&
426 (((uio->uio_td != NULL) ? uio->uio_td : curthread)->td_pflags &
427 TDP_DEADLKTREAT) == 0) {
428 int secsize; /* Media sector size */
429 off_t filebytes; /* Bytes left of file */
430 int blockbytes; /* Bytes left of file in full blocks */
431 int partialbytes; /* Bytes in last partial block */
432 int skipbytes; /* Bytes not to read in ffs_rawread */
433 struct inode *ip;
434 int error;
435
436
437 /* Only handle sector aligned reads */
438 ip = VTOI(vp);
439 secsize = ITODEVVP(ip)->v_bufobj.bo_bsize;
440 if ((uio->uio_offset & (secsize - 1)) == 0 &&
441 (uio->uio_resid & (secsize - 1)) == 0) {
442
443 /* Sync dirty pages and buffers if needed */
444 error = ffs_rawread_sync(vp);
445 if (error != 0)
446 return error;
447
448 /* Check for end of file */
449 if (ip->i_size > uio->uio_offset) {
450 filebytes = ip->i_size - uio->uio_offset;
451
452 /* No special eof handling needed ? */
453 if (uio->uio_resid <= filebytes) {
454 *workdone = 1;
455 return ffs_rawread_main(vp, uio);
456 }
457
458 partialbytes = ((unsigned int) ip->i_size) %
459 ITOFS(ip)->fs_bsize;
460 blockbytes = (int) filebytes - partialbytes;
461 if (blockbytes > 0) {
462 skipbytes = uio->uio_resid -
463 blockbytes;
464 uio->uio_resid = blockbytes;
465 error = ffs_rawread_main(vp, uio);
466 uio->uio_resid += skipbytes;
467 if (error != 0)
468 return error;
469 /* Read remaining part using buffer */
470 }
471 }
472 }
473 }
474 *workdone = 0;
475 return 0;
476 }
477