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Linux-2.6.12-rc2
[deliverable/linux.git] / fs / xfs / linux-2.6 / xfs_lrw.c
1 /*
2 * Copyright (c) 2000-2003 Silicon Graphics, Inc. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of version 2 of the GNU General Public License as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it would be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
11 *
12 * Further, this software is distributed without any warranty that it is
13 * free of the rightful claim of any third person regarding infringement
14 * or the like. Any license provided herein, whether implied or
15 * otherwise, applies only to this software file. Patent licenses, if
16 * any, provided herein do not apply to combinations of this program with
17 * other software, or any other product whatsoever.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write the Free Software Foundation, Inc., 59
21 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
22 *
23 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
24 * Mountain View, CA 94043, or:
25 *
26 * http://www.sgi.com
27 *
28 * For further information regarding this notice, see:
29 *
30 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
31 */
32 /*
33 * fs/xfs/linux/xfs_lrw.c (Linux Read Write stuff)
34 *
35 */
36
37 #include "xfs.h"
38
39 #include "xfs_fs.h"
40 #include "xfs_inum.h"
41 #include "xfs_log.h"
42 #include "xfs_trans.h"
43 #include "xfs_sb.h"
44 #include "xfs_ag.h"
45 #include "xfs_dir.h"
46 #include "xfs_dir2.h"
47 #include "xfs_alloc.h"
48 #include "xfs_dmapi.h"
49 #include "xfs_quota.h"
50 #include "xfs_mount.h"
51 #include "xfs_alloc_btree.h"
52 #include "xfs_bmap_btree.h"
53 #include "xfs_ialloc_btree.h"
54 #include "xfs_btree.h"
55 #include "xfs_ialloc.h"
56 #include "xfs_attr_sf.h"
57 #include "xfs_dir_sf.h"
58 #include "xfs_dir2_sf.h"
59 #include "xfs_dinode.h"
60 #include "xfs_inode.h"
61 #include "xfs_bmap.h"
62 #include "xfs_bit.h"
63 #include "xfs_rtalloc.h"
64 #include "xfs_error.h"
65 #include "xfs_itable.h"
66 #include "xfs_rw.h"
67 #include "xfs_acl.h"
68 #include "xfs_cap.h"
69 #include "xfs_mac.h"
70 #include "xfs_attr.h"
71 #include "xfs_inode_item.h"
72 #include "xfs_buf_item.h"
73 #include "xfs_utils.h"
74 #include "xfs_iomap.h"
75
76 #include <linux/capability.h>
77 #include <linux/writeback.h>
78
79
80 #if defined(XFS_RW_TRACE)
81 void
82 xfs_rw_enter_trace(
83 int tag,
84 xfs_iocore_t *io,
85 void *data,
86 size_t segs,
87 loff_t offset,
88 int ioflags)
89 {
90 xfs_inode_t *ip = XFS_IO_INODE(io);
91
92 if (ip->i_rwtrace == NULL)
93 return;
94 ktrace_enter(ip->i_rwtrace,
95 (void *)(unsigned long)tag,
96 (void *)ip,
97 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
98 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
99 (void *)data,
100 (void *)((unsigned long)segs),
101 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
102 (void *)((unsigned long)(offset & 0xffffffff)),
103 (void *)((unsigned long)ioflags),
104 (void *)((unsigned long)((io->io_new_size >> 32) & 0xffffffff)),
105 (void *)((unsigned long)(io->io_new_size & 0xffffffff)),
106 (void *)NULL,
107 (void *)NULL,
108 (void *)NULL,
109 (void *)NULL,
110 (void *)NULL);
111 }
112
113 void
114 xfs_inval_cached_trace(
115 xfs_iocore_t *io,
116 xfs_off_t offset,
117 xfs_off_t len,
118 xfs_off_t first,
119 xfs_off_t last)
120 {
121 xfs_inode_t *ip = XFS_IO_INODE(io);
122
123 if (ip->i_rwtrace == NULL)
124 return;
125 ktrace_enter(ip->i_rwtrace,
126 (void *)(__psint_t)XFS_INVAL_CACHED,
127 (void *)ip,
128 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
129 (void *)((unsigned long)(offset & 0xffffffff)),
130 (void *)((unsigned long)((len >> 32) & 0xffffffff)),
131 (void *)((unsigned long)(len & 0xffffffff)),
132 (void *)((unsigned long)((first >> 32) & 0xffffffff)),
133 (void *)((unsigned long)(first & 0xffffffff)),
134 (void *)((unsigned long)((last >> 32) & 0xffffffff)),
135 (void *)((unsigned long)(last & 0xffffffff)),
136 (void *)NULL,
137 (void *)NULL,
138 (void *)NULL,
139 (void *)NULL,
140 (void *)NULL,
141 (void *)NULL);
142 }
143 #endif
144
145 /*
146 * xfs_iozero
147 *
148 * xfs_iozero clears the specified range of buffer supplied,
149 * and marks all the affected blocks as valid and modified. If
150 * an affected block is not allocated, it will be allocated. If
151 * an affected block is not completely overwritten, and is not
152 * valid before the operation, it will be read from disk before
153 * being partially zeroed.
154 */
155 STATIC int
156 xfs_iozero(
157 struct inode *ip, /* inode */
158 loff_t pos, /* offset in file */
159 size_t count, /* size of data to zero */
160 loff_t end_size) /* max file size to set */
161 {
162 unsigned bytes;
163 struct page *page;
164 struct address_space *mapping;
165 char *kaddr;
166 int status;
167
168 mapping = ip->i_mapping;
169 do {
170 unsigned long index, offset;
171
172 offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
173 index = pos >> PAGE_CACHE_SHIFT;
174 bytes = PAGE_CACHE_SIZE - offset;
175 if (bytes > count)
176 bytes = count;
177
178 status = -ENOMEM;
179 page = grab_cache_page(mapping, index);
180 if (!page)
181 break;
182
183 kaddr = kmap(page);
184 status = mapping->a_ops->prepare_write(NULL, page, offset,
185 offset + bytes);
186 if (status) {
187 goto unlock;
188 }
189
190 memset((void *) (kaddr + offset), 0, bytes);
191 flush_dcache_page(page);
192 status = mapping->a_ops->commit_write(NULL, page, offset,
193 offset + bytes);
194 if (!status) {
195 pos += bytes;
196 count -= bytes;
197 if (pos > i_size_read(ip))
198 i_size_write(ip, pos < end_size ? pos : end_size);
199 }
200
201 unlock:
202 kunmap(page);
203 unlock_page(page);
204 page_cache_release(page);
205 if (status)
206 break;
207 } while (count);
208
209 return (-status);
210 }
211
212 /*
213 * xfs_inval_cached_pages
214 *
215 * This routine is responsible for keeping direct I/O and buffered I/O
216 * somewhat coherent. From here we make sure that we're at least
217 * temporarily holding the inode I/O lock exclusively and then call
218 * the page cache to flush and invalidate any cached pages. If there
219 * are no cached pages this routine will be very quick.
220 */
221 void
222 xfs_inval_cached_pages(
223 vnode_t *vp,
224 xfs_iocore_t *io,
225 xfs_off_t offset,
226 int write,
227 int relock)
228 {
229 if (VN_CACHED(vp)) {
230 xfs_inval_cached_trace(io, offset, -1, ctooff(offtoct(offset)), -1);
231 VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(offset)), -1, FI_REMAPF_LOCKED);
232 }
233
234 }
235
236 ssize_t /* bytes read, or (-) error */
237 xfs_read(
238 bhv_desc_t *bdp,
239 struct kiocb *iocb,
240 const struct iovec *iovp,
241 unsigned int segs,
242 loff_t *offset,
243 int ioflags,
244 cred_t *credp)
245 {
246 struct file *file = iocb->ki_filp;
247 struct inode *inode = file->f_mapping->host;
248 size_t size = 0;
249 ssize_t ret;
250 xfs_fsize_t n;
251 xfs_inode_t *ip;
252 xfs_mount_t *mp;
253 vnode_t *vp;
254 unsigned long seg;
255
256 ip = XFS_BHVTOI(bdp);
257 vp = BHV_TO_VNODE(bdp);
258 mp = ip->i_mount;
259
260 XFS_STATS_INC(xs_read_calls);
261
262 /* START copy & waste from filemap.c */
263 for (seg = 0; seg < segs; seg++) {
264 const struct iovec *iv = &iovp[seg];
265
266 /*
267 * If any segment has a negative length, or the cumulative
268 * length ever wraps negative then return -EINVAL.
269 */
270 size += iv->iov_len;
271 if (unlikely((ssize_t)(size|iv->iov_len) < 0))
272 return XFS_ERROR(-EINVAL);
273 }
274 /* END copy & waste from filemap.c */
275
276 if (unlikely(ioflags & IO_ISDIRECT)) {
277 xfs_buftarg_t *target =
278 (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
279 mp->m_rtdev_targp : mp->m_ddev_targp;
280 if ((*offset & target->pbr_smask) ||
281 (size & target->pbr_smask)) {
282 if (*offset == ip->i_d.di_size) {
283 return (0);
284 }
285 return -XFS_ERROR(EINVAL);
286 }
287 }
288
289 n = XFS_MAXIOFFSET(mp) - *offset;
290 if ((n <= 0) || (size == 0))
291 return 0;
292
293 if (n < size)
294 size = n;
295
296 if (XFS_FORCED_SHUTDOWN(mp)) {
297 return -EIO;
298 }
299
300 if (unlikely(ioflags & IO_ISDIRECT))
301 down(&inode->i_sem);
302 xfs_ilock(ip, XFS_IOLOCK_SHARED);
303
304 if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
305 !(ioflags & IO_INVIS)) {
306 vrwlock_t locktype = VRWLOCK_READ;
307
308 ret = -XFS_SEND_DATA(mp, DM_EVENT_READ,
309 BHV_TO_VNODE(bdp), *offset, size,
310 FILP_DELAY_FLAG(file), &locktype);
311 if (ret) {
312 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
313 goto unlock_isem;
314 }
315 }
316
317 xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,
318 (void *)iovp, segs, *offset, ioflags);
319 ret = __generic_file_aio_read(iocb, iovp, segs, offset);
320 if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
321 ret = wait_on_sync_kiocb(iocb);
322 if (ret > 0)
323 XFS_STATS_ADD(xs_read_bytes, ret);
324
325 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
326
327 if (likely(!(ioflags & IO_INVIS)))
328 xfs_ichgtime(ip, XFS_ICHGTIME_ACC);
329
330 unlock_isem:
331 if (unlikely(ioflags & IO_ISDIRECT))
332 up(&inode->i_sem);
333 return ret;
334 }
335
336 ssize_t
337 xfs_sendfile(
338 bhv_desc_t *bdp,
339 struct file *filp,
340 loff_t *offset,
341 int ioflags,
342 size_t count,
343 read_actor_t actor,
344 void *target,
345 cred_t *credp)
346 {
347 ssize_t ret;
348 xfs_fsize_t n;
349 xfs_inode_t *ip;
350 xfs_mount_t *mp;
351 vnode_t *vp;
352
353 ip = XFS_BHVTOI(bdp);
354 vp = BHV_TO_VNODE(bdp);
355 mp = ip->i_mount;
356
357 XFS_STATS_INC(xs_read_calls);
358
359 n = XFS_MAXIOFFSET(mp) - *offset;
360 if ((n <= 0) || (count == 0))
361 return 0;
362
363 if (n < count)
364 count = n;
365
366 if (XFS_FORCED_SHUTDOWN(ip->i_mount))
367 return -EIO;
368
369 xfs_ilock(ip, XFS_IOLOCK_SHARED);
370
371 if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
372 (!(ioflags & IO_INVIS))) {
373 vrwlock_t locktype = VRWLOCK_READ;
374 int error;
375
376 error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp), *offset, count,
377 FILP_DELAY_FLAG(filp), &locktype);
378 if (error) {
379 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
380 return -error;
381 }
382 }
383 xfs_rw_enter_trace(XFS_SENDFILE_ENTER, &ip->i_iocore,
384 (void *)(unsigned long)target, count, *offset, ioflags);
385 ret = generic_file_sendfile(filp, offset, count, actor, target);
386
387 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
388
389 if (ret > 0)
390 XFS_STATS_ADD(xs_read_bytes, ret);
391
392 if (likely(!(ioflags & IO_INVIS)))
393 xfs_ichgtime(ip, XFS_ICHGTIME_ACC);
394
395 return ret;
396 }
397
398 /*
399 * This routine is called to handle zeroing any space in the last
400 * block of the file that is beyond the EOF. We do this since the
401 * size is being increased without writing anything to that block
402 * and we don't want anyone to read the garbage on the disk.
403 */
404 STATIC int /* error (positive) */
405 xfs_zero_last_block(
406 struct inode *ip,
407 xfs_iocore_t *io,
408 xfs_off_t offset,
409 xfs_fsize_t isize,
410 xfs_fsize_t end_size)
411 {
412 xfs_fileoff_t last_fsb;
413 xfs_mount_t *mp;
414 int nimaps;
415 int zero_offset;
416 int zero_len;
417 int isize_fsb_offset;
418 int error = 0;
419 xfs_bmbt_irec_t imap;
420 loff_t loff;
421 size_t lsize;
422
423 ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
424 ASSERT(offset > isize);
425
426 mp = io->io_mount;
427
428 isize_fsb_offset = XFS_B_FSB_OFFSET(mp, isize);
429 if (isize_fsb_offset == 0) {
430 /*
431 * There are no extra bytes in the last block on disk to
432 * zero, so return.
433 */
434 return 0;
435 }
436
437 last_fsb = XFS_B_TO_FSBT(mp, isize);
438 nimaps = 1;
439 error = XFS_BMAPI(mp, NULL, io, last_fsb, 1, 0, NULL, 0, &imap,
440 &nimaps, NULL);
441 if (error) {
442 return error;
443 }
444 ASSERT(nimaps > 0);
445 /*
446 * If the block underlying isize is just a hole, then there
447 * is nothing to zero.
448 */
449 if (imap.br_startblock == HOLESTARTBLOCK) {
450 return 0;
451 }
452 /*
453 * Zero the part of the last block beyond the EOF, and write it
454 * out sync. We need to drop the ilock while we do this so we
455 * don't deadlock when the buffer cache calls back to us.
456 */
457 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
458 loff = XFS_FSB_TO_B(mp, last_fsb);
459 lsize = XFS_FSB_TO_B(mp, 1);
460
461 zero_offset = isize_fsb_offset;
462 zero_len = mp->m_sb.sb_blocksize - isize_fsb_offset;
463
464 error = xfs_iozero(ip, loff + zero_offset, zero_len, end_size);
465
466 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
467 ASSERT(error >= 0);
468 return error;
469 }
470
471 /*
472 * Zero any on disk space between the current EOF and the new,
473 * larger EOF. This handles the normal case of zeroing the remainder
474 * of the last block in the file and the unusual case of zeroing blocks
475 * out beyond the size of the file. This second case only happens
476 * with fixed size extents and when the system crashes before the inode
477 * size was updated but after blocks were allocated. If fill is set,
478 * then any holes in the range are filled and zeroed. If not, the holes
479 * are left alone as holes.
480 */
481
482 int /* error (positive) */
483 xfs_zero_eof(
484 vnode_t *vp,
485 xfs_iocore_t *io,
486 xfs_off_t offset, /* starting I/O offset */
487 xfs_fsize_t isize, /* current inode size */
488 xfs_fsize_t end_size) /* terminal inode size */
489 {
490 struct inode *ip = LINVFS_GET_IP(vp);
491 xfs_fileoff_t start_zero_fsb;
492 xfs_fileoff_t end_zero_fsb;
493 xfs_fileoff_t prev_zero_fsb;
494 xfs_fileoff_t zero_count_fsb;
495 xfs_fileoff_t last_fsb;
496 xfs_extlen_t buf_len_fsb;
497 xfs_extlen_t prev_zero_count;
498 xfs_mount_t *mp;
499 int nimaps;
500 int error = 0;
501 xfs_bmbt_irec_t imap;
502 loff_t loff;
503 size_t lsize;
504
505 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
506 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
507
508 mp = io->io_mount;
509
510 /*
511 * First handle zeroing the block on which isize resides.
512 * We only zero a part of that block so it is handled specially.
513 */
514 error = xfs_zero_last_block(ip, io, offset, isize, end_size);
515 if (error) {
516 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
517 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
518 return error;
519 }
520
521 /*
522 * Calculate the range between the new size and the old
523 * where blocks needing to be zeroed may exist. To get the
524 * block where the last byte in the file currently resides,
525 * we need to subtract one from the size and truncate back
526 * to a block boundary. We subtract 1 in case the size is
527 * exactly on a block boundary.
528 */
529 last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
530 start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
531 end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
532 ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
533 if (last_fsb == end_zero_fsb) {
534 /*
535 * The size was only incremented on its last block.
536 * We took care of that above, so just return.
537 */
538 return 0;
539 }
540
541 ASSERT(start_zero_fsb <= end_zero_fsb);
542 prev_zero_fsb = NULLFILEOFF;
543 prev_zero_count = 0;
544 while (start_zero_fsb <= end_zero_fsb) {
545 nimaps = 1;
546 zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
547 error = XFS_BMAPI(mp, NULL, io, start_zero_fsb, zero_count_fsb,
548 0, NULL, 0, &imap, &nimaps, NULL);
549 if (error) {
550 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
551 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
552 return error;
553 }
554 ASSERT(nimaps > 0);
555
556 if (imap.br_state == XFS_EXT_UNWRITTEN ||
557 imap.br_startblock == HOLESTARTBLOCK) {
558 /*
559 * This loop handles initializing pages that were
560 * partially initialized by the code below this
561 * loop. It basically zeroes the part of the page
562 * that sits on a hole and sets the page as P_HOLE
563 * and calls remapf if it is a mapped file.
564 */
565 prev_zero_fsb = NULLFILEOFF;
566 prev_zero_count = 0;
567 start_zero_fsb = imap.br_startoff +
568 imap.br_blockcount;
569 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
570 continue;
571 }
572
573 /*
574 * There are blocks in the range requested.
575 * Zero them a single write at a time. We actually
576 * don't zero the entire range returned if it is
577 * too big and simply loop around to get the rest.
578 * That is not the most efficient thing to do, but it
579 * is simple and this path should not be exercised often.
580 */
581 buf_len_fsb = XFS_FILBLKS_MIN(imap.br_blockcount,
582 mp->m_writeio_blocks << 8);
583 /*
584 * Drop the inode lock while we're doing the I/O.
585 * We'll still have the iolock to protect us.
586 */
587 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
588
589 loff = XFS_FSB_TO_B(mp, start_zero_fsb);
590 lsize = XFS_FSB_TO_B(mp, buf_len_fsb);
591
592 error = xfs_iozero(ip, loff, lsize, end_size);
593
594 if (error) {
595 goto out_lock;
596 }
597
598 prev_zero_fsb = start_zero_fsb;
599 prev_zero_count = buf_len_fsb;
600 start_zero_fsb = imap.br_startoff + buf_len_fsb;
601 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
602
603 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
604 }
605
606 return 0;
607
608 out_lock:
609
610 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
611 ASSERT(error >= 0);
612 return error;
613 }
614
615 ssize_t /* bytes written, or (-) error */
616 xfs_write(
617 bhv_desc_t *bdp,
618 struct kiocb *iocb,
619 const struct iovec *iovp,
620 unsigned int nsegs,
621 loff_t *offset,
622 int ioflags,
623 cred_t *credp)
624 {
625 struct file *file = iocb->ki_filp;
626 struct address_space *mapping = file->f_mapping;
627 struct inode *inode = mapping->host;
628 unsigned long segs = nsegs;
629 xfs_inode_t *xip;
630 xfs_mount_t *mp;
631 ssize_t ret = 0, error = 0;
632 xfs_fsize_t isize, new_size;
633 xfs_iocore_t *io;
634 vnode_t *vp;
635 unsigned long seg;
636 int iolock;
637 int eventsent = 0;
638 vrwlock_t locktype;
639 size_t ocount = 0, count;
640 loff_t pos;
641 int need_isem = 1, need_flush = 0;
642
643 XFS_STATS_INC(xs_write_calls);
644
645 vp = BHV_TO_VNODE(bdp);
646 xip = XFS_BHVTOI(bdp);
647
648 for (seg = 0; seg < segs; seg++) {
649 const struct iovec *iv = &iovp[seg];
650
651 /*
652 * If any segment has a negative length, or the cumulative
653 * length ever wraps negative then return -EINVAL.
654 */
655 ocount += iv->iov_len;
656 if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
657 return -EINVAL;
658 if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
659 continue;
660 if (seg == 0)
661 return -EFAULT;
662 segs = seg;
663 ocount -= iv->iov_len; /* This segment is no good */
664 break;
665 }
666
667 count = ocount;
668 pos = *offset;
669
670 if (count == 0)
671 return 0;
672
673 io = &xip->i_iocore;
674 mp = io->io_mount;
675
676 if (XFS_FORCED_SHUTDOWN(mp))
677 return -EIO;
678
679 fs_check_frozen(vp->v_vfsp, SB_FREEZE_WRITE);
680
681 if (ioflags & IO_ISDIRECT) {
682 xfs_buftarg_t *target =
683 (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
684 mp->m_rtdev_targp : mp->m_ddev_targp;
685
686 if ((pos & target->pbr_smask) || (count & target->pbr_smask))
687 return XFS_ERROR(-EINVAL);
688
689 if (!VN_CACHED(vp) && pos < i_size_read(inode))
690 need_isem = 0;
691
692 if (VN_CACHED(vp))
693 need_flush = 1;
694 }
695
696 relock:
697 if (need_isem) {
698 iolock = XFS_IOLOCK_EXCL;
699 locktype = VRWLOCK_WRITE;
700
701 down(&inode->i_sem);
702 } else {
703 iolock = XFS_IOLOCK_SHARED;
704 locktype = VRWLOCK_WRITE_DIRECT;
705 }
706
707 xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
708
709 isize = i_size_read(inode);
710
711 if (file->f_flags & O_APPEND)
712 *offset = isize;
713
714 start:
715 error = -generic_write_checks(file, &pos, &count,
716 S_ISBLK(inode->i_mode));
717 if (error) {
718 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
719 goto out_unlock_isem;
720 }
721
722 new_size = pos + count;
723 if (new_size > isize)
724 io->io_new_size = new_size;
725
726 if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) &&
727 !(ioflags & IO_INVIS) && !eventsent)) {
728 loff_t savedsize = pos;
729 int dmflags = FILP_DELAY_FLAG(file);
730
731 if (need_isem)
732 dmflags |= DM_FLAGS_ISEM;
733
734 xfs_iunlock(xip, XFS_ILOCK_EXCL);
735 error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp,
736 pos, count,
737 dmflags, &locktype);
738 if (error) {
739 xfs_iunlock(xip, iolock);
740 goto out_unlock_isem;
741 }
742 xfs_ilock(xip, XFS_ILOCK_EXCL);
743 eventsent = 1;
744
745 /*
746 * The iolock was dropped and reaquired in XFS_SEND_DATA
747 * so we have to recheck the size when appending.
748 * We will only "goto start;" once, since having sent the
749 * event prevents another call to XFS_SEND_DATA, which is
750 * what allows the size to change in the first place.
751 */
752 if ((file->f_flags & O_APPEND) && savedsize != isize) {
753 pos = isize = xip->i_d.di_size;
754 goto start;
755 }
756 }
757
758 /*
759 * On Linux, generic_file_write updates the times even if
760 * no data is copied in so long as the write had a size.
761 *
762 * We must update xfs' times since revalidate will overcopy xfs.
763 */
764 if (!(ioflags & IO_INVIS)) {
765 xfs_ichgtime(xip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
766 inode_update_time(inode, 1);
767 }
768
769 /*
770 * If the offset is beyond the size of the file, we have a couple
771 * of things to do. First, if there is already space allocated
772 * we need to either create holes or zero the disk or ...
773 *
774 * If there is a page where the previous size lands, we need
775 * to zero it out up to the new size.
776 */
777
778 if (pos > isize) {
779 error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos,
780 isize, pos + count);
781 if (error) {
782 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
783 goto out_unlock_isem;
784 }
785 }
786 xfs_iunlock(xip, XFS_ILOCK_EXCL);
787
788 /*
789 * If we're writing the file then make sure to clear the
790 * setuid and setgid bits if the process is not being run
791 * by root. This keeps people from modifying setuid and
792 * setgid binaries.
793 */
794
795 if (((xip->i_d.di_mode & S_ISUID) ||
796 ((xip->i_d.di_mode & (S_ISGID | S_IXGRP)) ==
797 (S_ISGID | S_IXGRP))) &&
798 !capable(CAP_FSETID)) {
799 error = xfs_write_clear_setuid(xip);
800 if (likely(!error))
801 error = -remove_suid(file->f_dentry);
802 if (unlikely(error)) {
803 xfs_iunlock(xip, iolock);
804 goto out_unlock_isem;
805 }
806 }
807
808 retry:
809 /* We can write back this queue in page reclaim */
810 current->backing_dev_info = mapping->backing_dev_info;
811
812 if ((ioflags & IO_ISDIRECT)) {
813 if (need_flush) {
814 xfs_inval_cached_trace(io, pos, -1,
815 ctooff(offtoct(pos)), -1);
816 VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(pos)),
817 -1, FI_REMAPF_LOCKED);
818 }
819
820 if (need_isem) {
821 /* demote the lock now the cached pages are gone */
822 XFS_ILOCK_DEMOTE(mp, io, XFS_IOLOCK_EXCL);
823 up(&inode->i_sem);
824
825 iolock = XFS_IOLOCK_SHARED;
826 locktype = VRWLOCK_WRITE_DIRECT;
827 need_isem = 0;
828 }
829
830 xfs_rw_enter_trace(XFS_DIOWR_ENTER, io, (void *)iovp, segs,
831 *offset, ioflags);
832 ret = generic_file_direct_write(iocb, iovp,
833 &segs, pos, offset, count, ocount);
834
835 /*
836 * direct-io write to a hole: fall through to buffered I/O
837 * for completing the rest of the request.
838 */
839 if (ret >= 0 && ret != count) {
840 XFS_STATS_ADD(xs_write_bytes, ret);
841
842 pos += ret;
843 count -= ret;
844
845 need_isem = 1;
846 ioflags &= ~IO_ISDIRECT;
847 xfs_iunlock(xip, iolock);
848 goto relock;
849 }
850 } else {
851 xfs_rw_enter_trace(XFS_WRITE_ENTER, io, (void *)iovp, segs,
852 *offset, ioflags);
853 ret = generic_file_buffered_write(iocb, iovp, segs,
854 pos, offset, count, ret);
855 }
856
857 current->backing_dev_info = NULL;
858
859 if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
860 ret = wait_on_sync_kiocb(iocb);
861
862 if ((ret == -ENOSPC) &&
863 DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_NOSPACE) &&
864 !(ioflags & IO_INVIS)) {
865
866 xfs_rwunlock(bdp, locktype);
867 error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, vp,
868 DM_RIGHT_NULL, vp, DM_RIGHT_NULL, NULL, NULL,
869 0, 0, 0); /* Delay flag intentionally unused */
870 if (error)
871 goto out_unlock_isem;
872 xfs_rwlock(bdp, locktype);
873 pos = xip->i_d.di_size;
874 ret = 0;
875 goto retry;
876 }
877
878 if (*offset > xip->i_d.di_size) {
879 xfs_ilock(xip, XFS_ILOCK_EXCL);
880 if (*offset > xip->i_d.di_size) {
881 xip->i_d.di_size = *offset;
882 i_size_write(inode, *offset);
883 xip->i_update_core = 1;
884 xip->i_update_size = 1;
885 }
886 xfs_iunlock(xip, XFS_ILOCK_EXCL);
887 }
888
889 error = -ret;
890 if (ret <= 0)
891 goto out_unlock_internal;
892
893 XFS_STATS_ADD(xs_write_bytes, ret);
894
895 /* Handle various SYNC-type writes */
896 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
897 /*
898 * If we're treating this as O_DSYNC and we have not updated the
899 * size, force the log.
900 */
901 if (!(mp->m_flags & XFS_MOUNT_OSYNCISOSYNC) &&
902 !(xip->i_update_size)) {
903 xfs_inode_log_item_t *iip = xip->i_itemp;
904
905 /*
906 * If an allocation transaction occurred
907 * without extending the size, then we have to force
908 * the log up the proper point to ensure that the
909 * allocation is permanent. We can't count on
910 * the fact that buffered writes lock out direct I/O
911 * writes - the direct I/O write could have extended
912 * the size nontransactionally, then finished before
913 * we started. xfs_write_file will think that the file
914 * didn't grow but the update isn't safe unless the
915 * size change is logged.
916 *
917 * Force the log if we've committed a transaction
918 * against the inode or if someone else has and
919 * the commit record hasn't gone to disk (e.g.
920 * the inode is pinned). This guarantees that
921 * all changes affecting the inode are permanent
922 * when we return.
923 */
924 if (iip && iip->ili_last_lsn) {
925 xfs_log_force(mp, iip->ili_last_lsn,
926 XFS_LOG_FORCE | XFS_LOG_SYNC);
927 } else if (xfs_ipincount(xip) > 0) {
928 xfs_log_force(mp, (xfs_lsn_t)0,
929 XFS_LOG_FORCE | XFS_LOG_SYNC);
930 }
931
932 } else {
933 xfs_trans_t *tp;
934
935 /*
936 * O_SYNC or O_DSYNC _with_ a size update are handled
937 * the same way.
938 *
939 * If the write was synchronous then we need to make
940 * sure that the inode modification time is permanent.
941 * We'll have updated the timestamp above, so here
942 * we use a synchronous transaction to log the inode.
943 * It's not fast, but it's necessary.
944 *
945 * If this a dsync write and the size got changed
946 * non-transactionally, then we need to ensure that
947 * the size change gets logged in a synchronous
948 * transaction.
949 */
950
951 tp = xfs_trans_alloc(mp, XFS_TRANS_WRITE_SYNC);
952 if ((error = xfs_trans_reserve(tp, 0,
953 XFS_SWRITE_LOG_RES(mp),
954 0, 0, 0))) {
955 /* Transaction reserve failed */
956 xfs_trans_cancel(tp, 0);
957 } else {
958 /* Transaction reserve successful */
959 xfs_ilock(xip, XFS_ILOCK_EXCL);
960 xfs_trans_ijoin(tp, xip, XFS_ILOCK_EXCL);
961 xfs_trans_ihold(tp, xip);
962 xfs_trans_log_inode(tp, xip, XFS_ILOG_CORE);
963 xfs_trans_set_sync(tp);
964 error = xfs_trans_commit(tp, 0, NULL);
965 xfs_iunlock(xip, XFS_ILOCK_EXCL);
966 }
967 if (error)
968 goto out_unlock_internal;
969 }
970
971 xfs_rwunlock(bdp, locktype);
972 if (need_isem)
973 up(&inode->i_sem);
974
975 error = sync_page_range(inode, mapping, pos, ret);
976 if (!error)
977 error = ret;
978 return error;
979 }
980
981 out_unlock_internal:
982 xfs_rwunlock(bdp, locktype);
983 out_unlock_isem:
984 if (need_isem)
985 up(&inode->i_sem);
986 return -error;
987 }
988
989 /*
990 * All xfs metadata buffers except log state machine buffers
991 * get this attached as their b_bdstrat callback function.
992 * This is so that we can catch a buffer
993 * after prematurely unpinning it to forcibly shutdown the filesystem.
994 */
995 int
996 xfs_bdstrat_cb(struct xfs_buf *bp)
997 {
998 xfs_mount_t *mp;
999
1000 mp = XFS_BUF_FSPRIVATE3(bp, xfs_mount_t *);
1001 if (!XFS_FORCED_SHUTDOWN(mp)) {
1002 pagebuf_iorequest(bp);
1003 return 0;
1004 } else {
1005 xfs_buftrace("XFS__BDSTRAT IOERROR", bp);
1006 /*
1007 * Metadata write that didn't get logged but
1008 * written delayed anyway. These aren't associated
1009 * with a transaction, and can be ignored.
1010 */
1011 if (XFS_BUF_IODONE_FUNC(bp) == NULL &&
1012 (XFS_BUF_ISREAD(bp)) == 0)
1013 return (xfs_bioerror_relse(bp));
1014 else
1015 return (xfs_bioerror(bp));
1016 }
1017 }
1018
1019
1020 int
1021 xfs_bmap(bhv_desc_t *bdp,
1022 xfs_off_t offset,
1023 ssize_t count,
1024 int flags,
1025 xfs_iomap_t *iomapp,
1026 int *niomaps)
1027 {
1028 xfs_inode_t *ip = XFS_BHVTOI(bdp);
1029 xfs_iocore_t *io = &ip->i_iocore;
1030
1031 ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
1032 ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
1033 ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
1034
1035 return xfs_iomap(io, offset, count, flags, iomapp, niomaps);
1036 }
1037
1038 /*
1039 * Wrapper around bdstrat so that we can stop data
1040 * from going to disk in case we are shutting down the filesystem.
1041 * Typically user data goes thru this path; one of the exceptions
1042 * is the superblock.
1043 */
1044 int
1045 xfsbdstrat(
1046 struct xfs_mount *mp,
1047 struct xfs_buf *bp)
1048 {
1049 ASSERT(mp);
1050 if (!XFS_FORCED_SHUTDOWN(mp)) {
1051 /* Grio redirection would go here
1052 * if (XFS_BUF_IS_GRIO(bp)) {
1053 */
1054
1055 pagebuf_iorequest(bp);
1056 return 0;
1057 }
1058
1059 xfs_buftrace("XFSBDSTRAT IOERROR", bp);
1060 return (xfs_bioerror_relse(bp));
1061 }
1062
1063 /*
1064 * If the underlying (data/log/rt) device is readonly, there are some
1065 * operations that cannot proceed.
1066 */
1067 int
1068 xfs_dev_is_read_only(
1069 xfs_mount_t *mp,
1070 char *message)
1071 {
1072 if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1073 xfs_readonly_buftarg(mp->m_logdev_targp) ||
1074 (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1075 cmn_err(CE_NOTE,
1076 "XFS: %s required on read-only device.", message);
1077 cmn_err(CE_NOTE,
1078 "XFS: write access unavailable, cannot proceed.");
1079 return EROFS;
1080 }
1081 return 0;
1082 }
Linux kernel - Deliverables
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