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Set allow_memio to 1 if fetching the allow_memio hint fails. This
[dragonfly.git] / sys / vfs / ufs / ffs_rawread.c
blob94bc6510e82c2520ba2ebcfc48b550719af417e1
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 * $FreeBSD: src/sys/ufs/ffs/ffs_rawread.c,v 1.3.2.2 2003/05/29 06:15:35 alc Exp $
27 * $DragonFly: src/sys/vfs/ufs/ffs_rawread.c,v 1.26 2006/08/12 00:26:21 dillon Exp $
28 */
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/mount.h>
37 #include <sys/namei.h>
38 #include <sys/vnode.h>
39 #include <sys/conf.h>
40 #include <sys/filio.h>
41 #include <sys/ttycom.h>
42 #include <sys/buf.h>
43 #include "quota.h"
44 #include "inode.h"
45 #include "fs.h"
46
47 #include <machine/limits.h>
48 #include <vm/vm.h>
49 #include <vm/vm_extern.h>
50 #include <vm/vm_object.h>
51 #include <sys/kernel.h>
52 #include <sys/sysctl.h>
53
54 static int ffs_rawread_readahead(struct vnode *vp, caddr_t udata, off_t offset,
55 size_t len, struct buf *bp, int *baseticks);
56 static int ffs_rawread_main(struct vnode *vp,
57 struct uio *uio);
58
59 static int ffs_rawread_sync(struct vnode *vp);
60
61 int ffs_rawread(struct vnode *vp, struct uio *uio, int *workdone);
62
63 void ffs_rawread_setup(void);
64
65 static void ffs_rawreadwakeup(struct bio *bio);
66
67
68 SYSCTL_DECL(_vfs_ffs);
69
70 static int ffsrawbufcnt = 4;
71 SYSCTL_INT(_vfs_ffs, OID_AUTO, ffsrawbufcnt, CTLFLAG_RD, &ffsrawbufcnt, 0,
72 "Buffers available for raw reads");
73
74 static int allowrawread = 1;
75 SYSCTL_INT(_vfs_ffs, OID_AUTO, allowrawread, CTLFLAG_RW, &allowrawread, 0,
76 "Flag to enable raw reads");
77
78 static int rawreadahead = 1;
79 SYSCTL_INT(_vfs_ffs, OID_AUTO, rawreadahead, CTLFLAG_RW, &rawreadahead, 0,
80 "Flag to enable readahead for long raw reads");
81
82
83 void
84 ffs_rawread_setup(void)
85 {
86 ffsrawbufcnt = (nswbuf > 100 ) ? (nswbuf - (nswbuf >> 4)) : nswbuf - 8;
87 }
88
89
90 static int
91 ffs_rawread_sync(struct vnode *vp)
92 {
93 int error;
94 int upgraded;
95
96 /* Check for dirty mmap, pending writes and dirty buffers */
97 crit_enter();
98 if (vp->v_track_write.bk_active > 0 ||
99 !RB_EMPTY(&vp->v_rbdirty_tree) ||
100 (vp->v_flag & VOBJDIRTY) != 0) {
101 crit_exit();
102
103 if (vn_islocked(vp) != LK_EXCLUSIVE) {
104 upgraded = 1;
105 /* Upgrade to exclusive lock, this might block */
106 vn_lock(vp, LK_UPGRADE);
107 } else
108 upgraded = 0;
109
110 /* Attempt to msync mmap() regions to clean dirty mmap */
111 if ((vp->v_flag & VOBJDIRTY) != 0) {
112 struct vm_object *obj;
113 if ((obj = vp->v_object) != NULL)
114 vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
115 }
116
117 /* Wait for pending writes to complete */
118 crit_enter();
119 while (vp->v_track_write.bk_active) {
120 vp->v_track_write.bk_waitflag = 1;
121 error = tsleep(&vp->v_track_write, 0, "rawrdfls", 0);
122 if (error != 0) {
123 crit_exit();
124 if (upgraded != 0)
125 vn_lock(vp, LK_DOWNGRADE);
126 return (error);
127 }
128 }
129 /* Flush dirty buffers */
130 if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
131 crit_exit();
132 if ((error = VOP_FSYNC(vp, MNT_WAIT)) != 0) {
133 if (upgraded != 0)
134 vn_lock(vp, LK_DOWNGRADE);
135 return (error);
136 }
137 crit_enter();
138 if (vp->v_track_write.bk_active > 0 ||
139 !RB_EMPTY(&vp->v_rbdirty_tree))
140 panic("ffs_rawread_sync: dirty bufs");
141 }
142 crit_exit();
143 if (upgraded != 0)
144 vn_lock(vp, LK_DOWNGRADE);
145 } else {
146 crit_exit();
147 }
148 return 0;
149 }
150
151
152 static int
153 ffs_rawread_readahead(struct vnode *vp, caddr_t udata, off_t loffset,
154 size_t len, struct buf *bp, int *baseticks)
155 {
156 int error;
157 int iolen;
158 int blockoff;
159 int bsize;
160 struct vnode *dp;
161 int bforwards;
162
163 bsize = vp->v_mount->mnt_stat.f_iosize;
164
165 /*
166 * Make sure it fits into the pbuf
167 */
168 iolen = (int)(intptr_t)udata & PAGE_MASK;
169 if (len + iolen > bp->b_kvasize) {
170 len = bp->b_kvasize;
171 if (iolen != 0)
172 len -= PAGE_SIZE;
173 }
174 bp->b_flags &= ~B_ERROR;
175 bp->b_loffset = loffset;
176 bp->b_bio2.bio_offset = NOOFFSET;
177 bp->b_bio2.bio_done = ffs_rawreadwakeup;
178
179 blockoff = (loffset % bsize) / DEV_BSIZE;
180
181 error = VOP_BMAP(vp, bp->b_loffset, &dp, &bp->b_bio2.bio_offset,
182 &bforwards, NULL);
183 if (error != 0) {
184 return error;
185 }
186 if (bp->b_bio2.bio_offset == NOOFFSET) {
187 /*
188 * Fill holes with NULs to preserve semantics
189 */
190 if (len + blockoff * DEV_BSIZE > bsize)
191 len = bsize - blockoff * DEV_BSIZE;
192
193 if (vmapbuf(bp, udata, len) < 0)
194 return EFAULT;
195
196 if (ticks - *baseticks >= hogticks) {
197 *baseticks = ticks;
198 uio_yield();
199 }
200 bzero(bp->b_data, bp->b_bcount);
201
202 /* Mark operation completed (similar to bufdone()) */
203
204 bp->b_resid = 0;
205 return 0;
206 }
207
208 if (len + blockoff * DEV_BSIZE > bforwards)
209 len = bforwards - blockoff * DEV_BSIZE;
210 bp->b_bio2.bio_offset += blockoff * DEV_BSIZE;
211
212 if (vmapbuf(bp, udata, len) < 0)
213 return EFAULT;
214
215 /*
216 * Access the block device layer using the device vnode (dp) and
217 * the translated block number (bio2) instead of the logical block
218 * number (bio1).
219 *
220 * Even though we are bypassing the vnode layer, we still
221 * want the vnode state to indicate that an I/O on its behalf
222 * is in progress.
223 */
224 bp->b_cmd = BUF_CMD_READ;
225 bio_start_transaction(&bp->b_bio1, &vp->v_track_read);
226 vn_strategy(dp, &bp->b_bio2);
227 return 0;
228 }
229
230 static int
231 ffs_rawread_main(struct vnode *vp, struct uio *uio)
232 {
233 int error, nerror;
234 struct buf *bp, *nbp, *tbp;
235 int iolen;
236 int baseticks = ticks;
237 caddr_t udata;
238 int resid;
239 off_t offset;
240
241 udata = uio->uio_iov->iov_base;
242 resid = uio->uio_resid;
243 offset = uio->uio_offset;
244
245 error = 0;
246 nerror = 0;
247
248 bp = NULL;
249 nbp = NULL;
250
251 while (resid > 0) {
252
253 if (bp == NULL) { /* Setup first read */
254 /* XXX: Leave some bufs for swap */
255 bp = getpbuf(&ffsrawbufcnt);
256 error = ffs_rawread_readahead(vp, udata, offset, resid,
257 bp, &baseticks);
258 if (error != 0)
259 break;
260
261 if (resid > bp->b_bufsize) { /* Setup fist readahead */
262 /* XXX: Leave bufs for swap */
263 if (rawreadahead != 0)
264 nbp = trypbuf(&ffsrawbufcnt);
265 else
266 nbp = NULL;
267 if (nbp != NULL) {
268 nerror = ffs_rawread_readahead(
269 vp,
270 udata + bp->b_bufsize,
271 offset + bp->b_bufsize,
272 resid - bp->b_bufsize,
273 nbp, &baseticks);
274 if (nerror) {
275 relpbuf(nbp, &ffsrawbufcnt);
276 nbp = NULL;
277 }
278 }
279 }
280 }
281
282 crit_enter();
283 while (bp->b_cmd != BUF_CMD_DONE)
284 tsleep((caddr_t)&bp->b_bio2, 0, "rawrd", 0);
285 crit_exit();
286
287 vunmapbuf(bp);
288
289 iolen = bp->b_bcount - bp->b_resid;
290 if (iolen == 0 && (bp->b_flags & B_ERROR) == 0) {
291 nerror = 0; /* Ignore possible beyond EOF error */
292 break; /* EOF */
293 }
294
295 if ((bp->b_flags & B_ERROR) != 0) {
296 error = bp->b_error;
297 break;
298 }
299 clearbiocache(&bp->b_bio2);
300 resid -= iolen;
301 udata += iolen;
302 offset += iolen;
303 if (iolen < bp->b_bufsize) {
304 /* Incomplete read. Try to read remaining part */
305 error = ffs_rawread_readahead(
306 vp, udata, offset,
307 bp->b_bufsize - iolen, bp, &baseticks);
308 if (error != 0)
309 break;
310 } else if (nbp != NULL) { /* Complete read with readahead */
311
312 tbp = bp;
313 bp = nbp;
314 nbp = tbp;
315
316 clearbiocache(&nbp->b_bio2);
317
318 if (resid <= bp->b_bufsize) { /* No more readaheads */
319 relpbuf(nbp, &ffsrawbufcnt);
320 nbp = NULL;
321 } else { /* Setup next readahead */
322 nerror = ffs_rawread_readahead(
323 vp, udata + bp->b_bufsize,
324 offset + bp->b_bufsize,
325 resid - bp->b_bufsize,
326 nbp, &baseticks);
327 if (nerror != 0) {
328 relpbuf(nbp, &ffsrawbufcnt);
329 nbp = NULL;
330 }
331 }
332 } else if (nerror != 0) {/* Deferred Readahead error */
333 break;
334 } else if (resid > 0) { /* More to read, no readahead */
335 error = ffs_rawread_readahead(vp, udata, offset,
336 resid, bp,
337 &baseticks);
338 if (error != 0)
339 break;
340 }
341 }
342
343 if (bp != NULL)
344 relpbuf(bp, &ffsrawbufcnt);
345 if (nbp != NULL) { /* Run down readahead buffer */
346 crit_enter();
347 while (nbp->b_cmd != BUF_CMD_DONE)
348 tsleep(&nbp->b_bio2, 0, "rawrd", 0);
349 crit_exit();
350 vunmapbuf(nbp);
351 relpbuf(nbp, &ffsrawbufcnt);
352 }
353
354 if (error == 0)
355 error = nerror;
356 uio->uio_iov->iov_base = udata;
357 uio->uio_resid = resid;
358 uio->uio_offset = offset;
359 return error;
360 }
361
362
363 int
364 ffs_rawread(struct vnode *vp,
365 struct uio *uio,
366 int *workdone)
367 {
368 if (allowrawread != 0 &&
369 uio->uio_iovcnt == 1 &&
370 uio->uio_segflg == UIO_USERSPACE &&
371 uio->uio_resid == uio->uio_iov->iov_len &&
372 (curthread->td_flags & TDF_DEADLKTREAT) == 0) {
373 int secsize; /* Media sector size */
374 off_t filebytes; /* Bytes left of file */
375 int blockbytes; /* Bytes left of file in full blocks */
376 int partialbytes; /* Bytes in last partial block */
377 int skipbytes; /* Bytes not to read in ffs_rawread */
378 struct inode *ip;
379 int error;
380
381
382 /* Only handle sector aligned reads */
383 ip = VTOI(vp);
384 secsize = ip->i_devvp->v_rdev->si_bsize_phys;
385 if ((uio->uio_offset & (secsize - 1)) == 0 &&
386 (uio->uio_resid & (secsize - 1)) == 0) {
387
388 /* Sync dirty pages and buffers if needed */
389 error = ffs_rawread_sync(vp);
390 if (error != 0)
391 return error;
392
393 /* Check for end of file */
394 if (ip->i_size > uio->uio_offset) {
395 filebytes = ip->i_size - uio->uio_offset;
396
397 /* No special eof handling needed ? */
398 if (uio->uio_resid <= filebytes) {
399 *workdone = 1;
400 return ffs_rawread_main(vp, uio);
401 }
402
403 partialbytes = ((unsigned int) ip->i_size) %
404 ip->i_fs->fs_bsize;
405 blockbytes = (int) filebytes - partialbytes;
406 if (blockbytes > 0) {
407 skipbytes = uio->uio_resid -
408 blockbytes;
409 uio->uio_resid = blockbytes;
410 error = ffs_rawread_main(vp, uio);
411 uio->uio_resid += skipbytes;
412 if (error != 0)
413 return error;
414 /* Read remaining part using buffer */
415 }
416 }
417 }
418 }
419 *workdone = 0;
420 return 0;
421 }
422
423
424 static void
425 ffs_rawreadwakeup(struct bio *bio)
426 {
427 bio->bio_buf->b_cmd = BUF_CMD_DONE;
428 wakeup(bio);
429 }
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