kernel - lwkt_token revamp
[dragonfly.git] / sys / vfs / ufs / ffs_rawread.c
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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 $
e92ca23a 27 * $DragonFly: src/sys/vfs/ufs/ffs_rawread.c,v 1.28 2008/06/19 23:27:39 dillon Exp $
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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>
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43#include "quota.h"
44#include "inode.h"
45#include "fs.h"
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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
2d53bf02 54static int ffs_rawread_readahead(struct vnode *vp, caddr_t udata, off_t offset,
a11aaa81 55 size_t len, struct buf *bp, int *baseticks);
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56static int ffs_rawread_main(struct vnode *vp,
57 struct uio *uio);
58
a11aaa81 59static int ffs_rawread_sync(struct vnode *vp);
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60
61int ffs_rawread(struct vnode *vp, struct uio *uio, int *workdone);
62
63void ffs_rawread_setup(void);
64
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65SYSCTL_DECL(_vfs_ffs);
66
67static int ffsrawbufcnt = 4;
68SYSCTL_INT(_vfs_ffs, OID_AUTO, ffsrawbufcnt, CTLFLAG_RD, &ffsrawbufcnt, 0,
69 "Buffers available for raw reads");
70
71static int allowrawread = 1;
72SYSCTL_INT(_vfs_ffs, OID_AUTO, allowrawread, CTLFLAG_RW, &allowrawread, 0,
73 "Flag to enable raw reads");
74
75static int rawreadahead = 1;
76SYSCTL_INT(_vfs_ffs, OID_AUTO, rawreadahead, CTLFLAG_RW, &rawreadahead, 0,
77 "Flag to enable readahead for long raw reads");
78
79
80void
81ffs_rawread_setup(void)
82{
83 ffsrawbufcnt = (nswbuf > 100 ) ? (nswbuf - (nswbuf >> 4)) : nswbuf - 8;
84}
85
86
87static int
a11aaa81 88ffs_rawread_sync(struct vnode *vp)
984263bc 89{
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90 int error;
91 int upgraded;
92
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93 /*
94 * Check for dirty mmap, pending writes and dirty buffers
95 */
3b998fa9 96 lwkt_gettoken(&vp->v_token);
a9a20f98 97 if (bio_track_active(&vp->v_track_write) ||
6bae6177 98 !RB_EMPTY(&vp->v_rbdirty_tree) ||
984263bc 99 (vp->v_flag & VOBJDIRTY) != 0) {
a11aaa81 100 if (vn_islocked(vp) != LK_EXCLUSIVE) {
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101 upgraded = 1;
102 /* Upgrade to exclusive lock, this might block */
a11aaa81 103 vn_lock(vp, LK_UPGRADE);
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104 } else
105 upgraded = 0;
106
107 /* Attempt to msync mmap() regions to clean dirty mmap */
108 if ((vp->v_flag & VOBJDIRTY) != 0) {
109 struct vm_object *obj;
7540ab49 110 if ((obj = vp->v_object) != NULL)
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111 vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
112 }
113
114 /* Wait for pending writes to complete */
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115 error = bio_track_wait(&vp->v_track_write, 0, 0);
116 if (error != 0) {
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117 if (upgraded != 0)
118 vn_lock(vp, LK_DOWNGRADE);
0202303b 119 goto done;
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120 }
121 /* Flush dirty buffers */
6bae6177 122 if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
52174f71 123 if ((error = VOP_FSYNC(vp, MNT_WAIT, 0)) != 0) {
984263bc 124 if (upgraded != 0)
a11aaa81 125 vn_lock(vp, LK_DOWNGRADE);
0202303b 126 goto done;
984263bc 127 }
a9a20f98 128 if (bio_track_active(&vp->v_track_write) ||
6bae6177 129 !RB_EMPTY(&vp->v_rbdirty_tree))
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130 panic("ffs_rawread_sync: dirty bufs");
131 }
984263bc 132 if (upgraded != 0)
a11aaa81 133 vn_lock(vp, LK_DOWNGRADE);
984263bc 134 } else {
0202303b 135 error = 0;
984263bc 136 }
0202303b 137done:
3b998fa9 138 lwkt_reltoken(&vp->v_token);
0202303b 139 return error;
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140}
141
142
143static int
81b5c339 144ffs_rawread_readahead(struct vnode *vp, caddr_t udata, off_t loffset,
a11aaa81 145 size_t len, struct buf *bp, int *baseticks)
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146{
147 int error;
3591bbc6 148 int iolen;
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149 int blockoff;
150 int bsize;
151 struct vnode *dp;
152 int bforwards;
153
154 bsize = vp->v_mount->mnt_stat.f_iosize;
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155
156 /*
157 * Make sure it fits into the pbuf
158 */
159 iolen = (int)(intptr_t)udata & PAGE_MASK;
160 if (len + iolen > bp->b_kvasize) {
161 len = bp->b_kvasize;
984263bc 162 if (iolen != 0)
3591bbc6 163 len -= PAGE_SIZE;
984263bc 164 }
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165
166 /*
167 * Raw disk address is in bio2, but we wait for it to
168 * chain to bio1.
169 */
10f3fee5 170 bp->b_flags &= ~B_ERROR;
81b5c339 171 bp->b_loffset = loffset;
81b5c339 172 bp->b_bio2.bio_offset = NOOFFSET;
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173 bp->b_bio1.bio_done = biodone_sync;
174 bp->b_bio1.bio_flags |= BIO_SYNC;
81b5c339 175
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176 blockoff = (loffset % bsize) / DEV_BSIZE;
177
08daea96 178 error = VOP_BMAP(vp, bp->b_loffset, &bp->b_bio2.bio_offset,
e92ca23a 179 &bforwards, NULL, BUF_CMD_READ);
08daea96 180 if (error != 0)
984263bc 181 return error;
08daea96 182 dp = VTOI(vp)->i_devvp;
54078292 183 if (bp->b_bio2.bio_offset == NOOFFSET) {
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184 /*
185 * Fill holes with NULs to preserve semantics
186 */
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187 if (len + blockoff * DEV_BSIZE > bsize)
188 len = bsize - blockoff * DEV_BSIZE;
984263bc 189
3591bbc6 190 if (vmapbuf(bp, udata, len) < 0)
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191 return EFAULT;
192
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193 if (ticks - *baseticks >= hogticks) {
194 *baseticks = ticks;
984263bc 195 uio_yield();
2d53bf02 196 }
3591bbc6 197 bzero(bp->b_data, bp->b_bcount);
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198
199 /* Mark operation completed (similar to bufdone()) */
200
201 bp->b_resid = 0;
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202 return 0;
203 }
204
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205 if (len + blockoff * DEV_BSIZE > bforwards)
206 len = bforwards - blockoff * DEV_BSIZE;
54078292 207 bp->b_bio2.bio_offset += blockoff * DEV_BSIZE;
984263bc 208
3591bbc6 209 if (vmapbuf(bp, udata, len) < 0)
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210 return EFAULT;
211
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212 /*
213 * Access the block device layer using the device vnode (dp) and
214 * the translated block number (bio2) instead of the logical block
215 * number (bio1).
216 *
217 * Even though we are bypassing the vnode layer, we still
218 * want the vnode state to indicate that an I/O on its behalf
219 * is in progress.
220 */
10f3fee5 221 bp->b_cmd = BUF_CMD_READ;
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222 bio_start_transaction(&bp->b_bio1, &vp->v_track_read);
223 vn_strategy(dp, &bp->b_bio2);
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224 return 0;
225}
226
984263bc 227static int
2d53bf02 228ffs_rawread_main(struct vnode *vp, struct uio *uio)
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229{
230 int error, nerror;
231 struct buf *bp, *nbp, *tbp;
3591bbc6 232 int iolen;
2d53bf02 233 int baseticks = ticks;
984263bc 234 caddr_t udata;
54078292 235 int resid;
984263bc 236 off_t offset;
984263bc 237
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238 udata = uio->uio_iov->iov_base;
239 resid = uio->uio_resid;
240 offset = uio->uio_offset;
241
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242 error = 0;
243 nerror = 0;
244
245 bp = NULL;
246 nbp = NULL;
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247
248 while (resid > 0) {
249
250 if (bp == NULL) { /* Setup first read */
251 /* XXX: Leave some bufs for swap */
252 bp = getpbuf(&ffsrawbufcnt);
2d53bf02 253 error = ffs_rawread_readahead(vp, udata, offset, resid,
a11aaa81 254 bp, &baseticks);
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255 if (error != 0)
256 break;
257
258 if (resid > bp->b_bufsize) { /* Setup fist readahead */
259 /* XXX: Leave bufs for swap */
260 if (rawreadahead != 0)
261 nbp = trypbuf(&ffsrawbufcnt);
262 else
263 nbp = NULL;
264 if (nbp != NULL) {
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265 nerror = ffs_rawread_readahead(
266 vp,
267 udata + bp->b_bufsize,
268 offset + bp->b_bufsize,
269 resid - bp->b_bufsize,
a11aaa81 270 nbp, &baseticks);
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271 if (nerror) {
272 relpbuf(nbp, &ffsrawbufcnt);
273 nbp = NULL;
274 }
275 }
276 }
277 }
278
ae8e83e6 279 biowait(&bp->b_bio1, "rawrd");
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280
281 vunmapbuf(bp);
282
283 iolen = bp->b_bcount - bp->b_resid;
284 if (iolen == 0 && (bp->b_flags & B_ERROR) == 0) {
285 nerror = 0; /* Ignore possible beyond EOF error */
286 break; /* EOF */
287 }
288
289 if ((bp->b_flags & B_ERROR) != 0) {
290 error = bp->b_error;
291 break;
292 }
81b5c339 293 clearbiocache(&bp->b_bio2);
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294 resid -= iolen;
295 udata += iolen;
296 offset += iolen;
297 if (iolen < bp->b_bufsize) {
298 /* Incomplete read. Try to read remaining part */
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299 error = ffs_rawread_readahead(
300 vp, udata, offset,
a11aaa81 301 bp->b_bufsize - iolen, bp, &baseticks);
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302 if (error != 0)
303 break;
304 } else if (nbp != NULL) { /* Complete read with readahead */
305
306 tbp = bp;
307 bp = nbp;
308 nbp = tbp;
309
81b5c339 310 clearbiocache(&nbp->b_bio2);
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311
312 if (resid <= bp->b_bufsize) { /* No more readaheads */
313 relpbuf(nbp, &ffsrawbufcnt);
314 nbp = NULL;
315 } else { /* Setup next readahead */
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316 nerror = ffs_rawread_readahead(
317 vp, udata + bp->b_bufsize,
318 offset + bp->b_bufsize,
319 resid - bp->b_bufsize,
a11aaa81 320 nbp, &baseticks);
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321 if (nerror != 0) {
322 relpbuf(nbp, &ffsrawbufcnt);
323 nbp = NULL;
324 }
325 }
326 } else if (nerror != 0) {/* Deferred Readahead error */
327 break;
328 } else if (resid > 0) { /* More to read, no readahead */
329 error = ffs_rawread_readahead(vp, udata, offset,
a11aaa81 330 resid, bp,
2d53bf02 331 &baseticks);
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332 if (error != 0)
333 break;
334 }
335 }
336
337 if (bp != NULL)
338 relpbuf(bp, &ffsrawbufcnt);
339 if (nbp != NULL) { /* Run down readahead buffer */
ae8e83e6 340 biowait(&nbp->b_bio1, "rawrd");
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341 vunmapbuf(nbp);
342 relpbuf(nbp, &ffsrawbufcnt);
343 }
344
345 if (error == 0)
346 error = nerror;
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347 uio->uio_iov->iov_base = udata;
348 uio->uio_resid = resid;
349 uio->uio_offset = offset;
350 return error;
351}
352
353
354int
355ffs_rawread(struct vnode *vp,
356 struct uio *uio,
357 int *workdone)
358{
359 if (allowrawread != 0 &&
360 uio->uio_iovcnt == 1 &&
361 uio->uio_segflg == UIO_USERSPACE &&
362 uio->uio_resid == uio->uio_iov->iov_len &&
a11aaa81 363 (curthread->td_flags & TDF_DEADLKTREAT) == 0) {
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364 int secsize; /* Media sector size */
365 off_t filebytes; /* Bytes left of file */
366 int blockbytes; /* Bytes left of file in full blocks */
367 int partialbytes; /* Bytes in last partial block */
368 int skipbytes; /* Bytes not to read in ffs_rawread */
369 struct inode *ip;
370 int error;
371
372
373 /* Only handle sector aligned reads */
374 ip = VTOI(vp);
375 secsize = ip->i_devvp->v_rdev->si_bsize_phys;
376 if ((uio->uio_offset & (secsize - 1)) == 0 &&
377 (uio->uio_resid & (secsize - 1)) == 0) {
378
379 /* Sync dirty pages and buffers if needed */
a11aaa81 380 error = ffs_rawread_sync(vp);
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381 if (error != 0)
382 return error;
383
384 /* Check for end of file */
385 if (ip->i_size > uio->uio_offset) {
386 filebytes = ip->i_size - uio->uio_offset;
387
388 /* No special eof handling needed ? */
389 if (uio->uio_resid <= filebytes) {
390 *workdone = 1;
391 return ffs_rawread_main(vp, uio);
392 }
393
394 partialbytes = ((unsigned int) ip->i_size) %
395 ip->i_fs->fs_bsize;
396 blockbytes = (int) filebytes - partialbytes;
397 if (blockbytes > 0) {
398 skipbytes = uio->uio_resid -
399 blockbytes;
400 uio->uio_resid = blockbytes;
401 error = ffs_rawread_main(vp, uio);
402 uio->uio_resid += skipbytes;
403 if (error != 0)
404 return error;
405 /* Read remaining part using buffer */
406 }
407 }
408 }
409 }
410 *workdone = 0;
411 return 0;
412}
413