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[XFS] We really suck at spulling. Thanks to Chris Pascoe for fixing all
[deliverable/linux.git] / fs / xfs / linux-2.6 / xfs_lrw.c
1 /*
2 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_bit.h"
21 #include "xfs_log.h"
22 #include "xfs_inum.h"
23 #include "xfs_trans.h"
24 #include "xfs_sb.h"
25 #include "xfs_ag.h"
26 #include "xfs_dir.h"
27 #include "xfs_dir2.h"
28 #include "xfs_alloc.h"
29 #include "xfs_dmapi.h"
30 #include "xfs_quota.h"
31 #include "xfs_mount.h"
32 #include "xfs_bmap_btree.h"
33 #include "xfs_alloc_btree.h"
34 #include "xfs_ialloc_btree.h"
35 #include "xfs_dir_sf.h"
36 #include "xfs_dir2_sf.h"
37 #include "xfs_attr_sf.h"
38 #include "xfs_dinode.h"
39 #include "xfs_inode.h"
40 #include "xfs_bmap.h"
41 #include "xfs_btree.h"
42 #include "xfs_ialloc.h"
43 #include "xfs_rtalloc.h"
44 #include "xfs_error.h"
45 #include "xfs_itable.h"
46 #include "xfs_rw.h"
47 #include "xfs_acl.h"
48 #include "xfs_cap.h"
49 #include "xfs_mac.h"
50 #include "xfs_attr.h"
51 #include "xfs_inode_item.h"
52 #include "xfs_buf_item.h"
53 #include "xfs_utils.h"
54 #include "xfs_iomap.h"
55
56 #include <linux/capability.h>
57 #include <linux/writeback.h>
58
59
60 #if defined(XFS_RW_TRACE)
61 void
62 xfs_rw_enter_trace(
63 int tag,
64 xfs_iocore_t *io,
65 void *data,
66 size_t segs,
67 loff_t offset,
68 int ioflags)
69 {
70 xfs_inode_t *ip = XFS_IO_INODE(io);
71
72 if (ip->i_rwtrace == NULL)
73 return;
74 ktrace_enter(ip->i_rwtrace,
75 (void *)(unsigned long)tag,
76 (void *)ip,
77 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
78 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
79 (void *)data,
80 (void *)((unsigned long)segs),
81 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
82 (void *)((unsigned long)(offset & 0xffffffff)),
83 (void *)((unsigned long)ioflags),
84 (void *)((unsigned long)((io->io_new_size >> 32) & 0xffffffff)),
85 (void *)((unsigned long)(io->io_new_size & 0xffffffff)),
86 (void *)((unsigned long)current_pid()),
87 (void *)NULL,
88 (void *)NULL,
89 (void *)NULL,
90 (void *)NULL);
91 }
92
93 void
94 xfs_inval_cached_trace(
95 xfs_iocore_t *io,
96 xfs_off_t offset,
97 xfs_off_t len,
98 xfs_off_t first,
99 xfs_off_t last)
100 {
101 xfs_inode_t *ip = XFS_IO_INODE(io);
102
103 if (ip->i_rwtrace == NULL)
104 return;
105 ktrace_enter(ip->i_rwtrace,
106 (void *)(__psint_t)XFS_INVAL_CACHED,
107 (void *)ip,
108 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
109 (void *)((unsigned long)(offset & 0xffffffff)),
110 (void *)((unsigned long)((len >> 32) & 0xffffffff)),
111 (void *)((unsigned long)(len & 0xffffffff)),
112 (void *)((unsigned long)((first >> 32) & 0xffffffff)),
113 (void *)((unsigned long)(first & 0xffffffff)),
114 (void *)((unsigned long)((last >> 32) & 0xffffffff)),
115 (void *)((unsigned long)(last & 0xffffffff)),
116 (void *)((unsigned long)current_pid()),
117 (void *)NULL,
118 (void *)NULL,
119 (void *)NULL,
120 (void *)NULL,
121 (void *)NULL);
122 }
123 #endif
124
125 /*
126 * xfs_iozero
127 *
128 * xfs_iozero clears the specified range of buffer supplied,
129 * and marks all the affected blocks as valid and modified. If
130 * an affected block is not allocated, it will be allocated. If
131 * an affected block is not completely overwritten, and is not
132 * valid before the operation, it will be read from disk before
133 * being partially zeroed.
134 */
135 STATIC int
136 xfs_iozero(
137 struct inode *ip, /* inode */
138 loff_t pos, /* offset in file */
139 size_t count, /* size of data to zero */
140 loff_t end_size) /* max file size to set */
141 {
142 unsigned bytes;
143 struct page *page;
144 struct address_space *mapping;
145 char *kaddr;
146 int status;
147
148 mapping = ip->i_mapping;
149 do {
150 unsigned long index, offset;
151
152 offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
153 index = pos >> PAGE_CACHE_SHIFT;
154 bytes = PAGE_CACHE_SIZE - offset;
155 if (bytes > count)
156 bytes = count;
157
158 status = -ENOMEM;
159 page = grab_cache_page(mapping, index);
160 if (!page)
161 break;
162
163 kaddr = kmap(page);
164 status = mapping->a_ops->prepare_write(NULL, page, offset,
165 offset + bytes);
166 if (status) {
167 goto unlock;
168 }
169
170 memset((void *) (kaddr + offset), 0, bytes);
171 flush_dcache_page(page);
172 status = mapping->a_ops->commit_write(NULL, page, offset,
173 offset + bytes);
174 if (!status) {
175 pos += bytes;
176 count -= bytes;
177 if (pos > i_size_read(ip))
178 i_size_write(ip, pos < end_size ? pos : end_size);
179 }
180
181 unlock:
182 kunmap(page);
183 unlock_page(page);
184 page_cache_release(page);
185 if (status)
186 break;
187 } while (count);
188
189 return (-status);
190 }
191
192 ssize_t /* bytes read, or (-) error */
193 xfs_read(
194 bhv_desc_t *bdp,
195 struct kiocb *iocb,
196 const struct iovec *iovp,
197 unsigned int segs,
198 loff_t *offset,
199 int ioflags,
200 cred_t *credp)
201 {
202 struct file *file = iocb->ki_filp;
203 struct inode *inode = file->f_mapping->host;
204 size_t size = 0;
205 ssize_t ret;
206 xfs_fsize_t n;
207 xfs_inode_t *ip;
208 xfs_mount_t *mp;
209 vnode_t *vp;
210 unsigned long seg;
211
212 ip = XFS_BHVTOI(bdp);
213 vp = BHV_TO_VNODE(bdp);
214 mp = ip->i_mount;
215
216 XFS_STATS_INC(xs_read_calls);
217
218 /* START copy & waste from filemap.c */
219 for (seg = 0; seg < segs; seg++) {
220 const struct iovec *iv = &iovp[seg];
221
222 /*
223 * If any segment has a negative length, or the cumulative
224 * length ever wraps negative then return -EINVAL.
225 */
226 size += iv->iov_len;
227 if (unlikely((ssize_t)(size|iv->iov_len) < 0))
228 return XFS_ERROR(-EINVAL);
229 }
230 /* END copy & waste from filemap.c */
231
232 if (unlikely(ioflags & IO_ISDIRECT)) {
233 xfs_buftarg_t *target =
234 (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
235 mp->m_rtdev_targp : mp->m_ddev_targp;
236 if ((*offset & target->bt_smask) ||
237 (size & target->bt_smask)) {
238 if (*offset == ip->i_d.di_size) {
239 return (0);
240 }
241 return -XFS_ERROR(EINVAL);
242 }
243 }
244
245 n = XFS_MAXIOFFSET(mp) - *offset;
246 if ((n <= 0) || (size == 0))
247 return 0;
248
249 if (n < size)
250 size = n;
251
252 if (XFS_FORCED_SHUTDOWN(mp))
253 return -EIO;
254
255 if (unlikely(ioflags & IO_ISDIRECT))
256 mutex_lock(&inode->i_mutex);
257 xfs_ilock(ip, XFS_IOLOCK_SHARED);
258
259 if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
260 !(ioflags & IO_INVIS)) {
261 vrwlock_t locktype = VRWLOCK_READ;
262 int dmflags = FILP_DELAY_FLAG(file) | DM_SEM_FLAG_RD(ioflags);
263
264 ret = -XFS_SEND_DATA(mp, DM_EVENT_READ,
265 BHV_TO_VNODE(bdp), *offset, size,
266 dmflags, &locktype);
267 if (ret) {
268 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
269 goto unlock_mutex;
270 }
271 }
272
273 if (unlikely((ioflags & IO_ISDIRECT) && VN_CACHED(vp)))
274 VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(*offset)),
275 -1, FI_REMAPF_LOCKED);
276
277 xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,
278 (void *)iovp, segs, *offset, ioflags);
279 ret = __generic_file_aio_read(iocb, iovp, segs, offset);
280 if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
281 ret = wait_on_sync_kiocb(iocb);
282 if (ret > 0)
283 XFS_STATS_ADD(xs_read_bytes, ret);
284
285 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
286
287 unlock_mutex:
288 if (unlikely(ioflags & IO_ISDIRECT))
289 mutex_unlock(&inode->i_mutex);
290 return ret;
291 }
292
293 ssize_t
294 xfs_sendfile(
295 bhv_desc_t *bdp,
296 struct file *filp,
297 loff_t *offset,
298 int ioflags,
299 size_t count,
300 read_actor_t actor,
301 void *target,
302 cred_t *credp)
303 {
304 ssize_t ret;
305 xfs_fsize_t n;
306 xfs_inode_t *ip;
307 xfs_mount_t *mp;
308 vnode_t *vp;
309
310 ip = XFS_BHVTOI(bdp);
311 vp = BHV_TO_VNODE(bdp);
312 mp = ip->i_mount;
313
314 XFS_STATS_INC(xs_read_calls);
315
316 n = XFS_MAXIOFFSET(mp) - *offset;
317 if ((n <= 0) || (count == 0))
318 return 0;
319
320 if (n < count)
321 count = n;
322
323 if (XFS_FORCED_SHUTDOWN(ip->i_mount))
324 return -EIO;
325
326 xfs_ilock(ip, XFS_IOLOCK_SHARED);
327
328 if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
329 (!(ioflags & IO_INVIS))) {
330 vrwlock_t locktype = VRWLOCK_READ;
331 int error;
332
333 error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp), *offset, count,
334 FILP_DELAY_FLAG(filp), &locktype);
335 if (error) {
336 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
337 return -error;
338 }
339 }
340 xfs_rw_enter_trace(XFS_SENDFILE_ENTER, &ip->i_iocore,
341 (void *)(unsigned long)target, count, *offset, ioflags);
342 ret = generic_file_sendfile(filp, offset, count, actor, target);
343
344 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
345
346 if (ret > 0)
347 XFS_STATS_ADD(xs_read_bytes, ret);
348
349 return ret;
350 }
351
352 /*
353 * This routine is called to handle zeroing any space in the last
354 * block of the file that is beyond the EOF. We do this since the
355 * size is being increased without writing anything to that block
356 * and we don't want anyone to read the garbage on the disk.
357 */
358 STATIC int /* error (positive) */
359 xfs_zero_last_block(
360 struct inode *ip,
361 xfs_iocore_t *io,
362 xfs_fsize_t isize,
363 xfs_fsize_t end_size)
364 {
365 xfs_fileoff_t last_fsb;
366 xfs_mount_t *mp;
367 int nimaps;
368 int zero_offset;
369 int zero_len;
370 int error = 0;
371 xfs_bmbt_irec_t imap;
372 loff_t loff;
373
374 ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
375
376 mp = io->io_mount;
377
378 zero_offset = XFS_B_FSB_OFFSET(mp, isize);
379 if (zero_offset == 0) {
380 /*
381 * There are no extra bytes in the last block on disk to
382 * zero, so return.
383 */
384 return 0;
385 }
386
387 last_fsb = XFS_B_TO_FSBT(mp, isize);
388 nimaps = 1;
389 error = XFS_BMAPI(mp, NULL, io, last_fsb, 1, 0, NULL, 0, &imap,
390 &nimaps, NULL);
391 if (error) {
392 return error;
393 }
394 ASSERT(nimaps > 0);
395 /*
396 * If the block underlying isize is just a hole, then there
397 * is nothing to zero.
398 */
399 if (imap.br_startblock == HOLESTARTBLOCK) {
400 return 0;
401 }
402 /*
403 * Zero the part of the last block beyond the EOF, and write it
404 * out sync. We need to drop the ilock while we do this so we
405 * don't deadlock when the buffer cache calls back to us.
406 */
407 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
408 loff = XFS_FSB_TO_B(mp, last_fsb);
409
410 zero_len = mp->m_sb.sb_blocksize - zero_offset;
411
412 error = xfs_iozero(ip, loff + zero_offset, zero_len, end_size);
413
414 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
415 ASSERT(error >= 0);
416 return error;
417 }
418
419 /*
420 * Zero any on disk space between the current EOF and the new,
421 * larger EOF. This handles the normal case of zeroing the remainder
422 * of the last block in the file and the unusual case of zeroing blocks
423 * out beyond the size of the file. This second case only happens
424 * with fixed size extents and when the system crashes before the inode
425 * size was updated but after blocks were allocated. If fill is set,
426 * then any holes in the range are filled and zeroed. If not, the holes
427 * are left alone as holes.
428 */
429
430 int /* error (positive) */
431 xfs_zero_eof(
432 vnode_t *vp,
433 xfs_iocore_t *io,
434 xfs_off_t offset, /* starting I/O offset */
435 xfs_fsize_t isize, /* current inode size */
436 xfs_fsize_t end_size) /* terminal inode size */
437 {
438 struct inode *ip = vn_to_inode(vp);
439 xfs_fileoff_t start_zero_fsb;
440 xfs_fileoff_t end_zero_fsb;
441 xfs_fileoff_t zero_count_fsb;
442 xfs_fileoff_t last_fsb;
443 xfs_extlen_t buf_len_fsb;
444 xfs_mount_t *mp;
445 int nimaps;
446 int error = 0;
447 xfs_bmbt_irec_t imap;
448
449 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
450 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
451 ASSERT(offset > isize);
452
453 mp = io->io_mount;
454
455 /*
456 * First handle zeroing the block on which isize resides.
457 * We only zero a part of that block so it is handled specially.
458 */
459 error = xfs_zero_last_block(ip, io, isize, end_size);
460 if (error) {
461 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
462 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
463 return error;
464 }
465
466 /*
467 * Calculate the range between the new size and the old
468 * where blocks needing to be zeroed may exist. To get the
469 * block where the last byte in the file currently resides,
470 * we need to subtract one from the size and truncate back
471 * to a block boundary. We subtract 1 in case the size is
472 * exactly on a block boundary.
473 */
474 last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
475 start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
476 end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
477 ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
478 if (last_fsb == end_zero_fsb) {
479 /*
480 * The size was only incremented on its last block.
481 * We took care of that above, so just return.
482 */
483 return 0;
484 }
485
486 ASSERT(start_zero_fsb <= end_zero_fsb);
487 while (start_zero_fsb <= end_zero_fsb) {
488 nimaps = 1;
489 zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
490 error = XFS_BMAPI(mp, NULL, io, start_zero_fsb, zero_count_fsb,
491 0, NULL, 0, &imap, &nimaps, NULL);
492 if (error) {
493 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
494 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
495 return error;
496 }
497 ASSERT(nimaps > 0);
498
499 if (imap.br_state == XFS_EXT_UNWRITTEN ||
500 imap.br_startblock == HOLESTARTBLOCK) {
501 /*
502 * This loop handles initializing pages that were
503 * partially initialized by the code below this
504 * loop. It basically zeroes the part of the page
505 * that sits on a hole and sets the page as P_HOLE
506 * and calls remapf if it is a mapped file.
507 */
508 start_zero_fsb = imap.br_startoff + imap.br_blockcount;
509 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
510 continue;
511 }
512
513 /*
514 * There are blocks in the range requested.
515 * Zero them a single write at a time. We actually
516 * don't zero the entire range returned if it is
517 * too big and simply loop around to get the rest.
518 * That is not the most efficient thing to do, but it
519 * is simple and this path should not be exercised often.
520 */
521 buf_len_fsb = XFS_FILBLKS_MIN(imap.br_blockcount,
522 mp->m_writeio_blocks << 8);
523 /*
524 * Drop the inode lock while we're doing the I/O.
525 * We'll still have the iolock to protect us.
526 */
527 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
528
529 error = xfs_iozero(ip,
530 XFS_FSB_TO_B(mp, start_zero_fsb),
531 XFS_FSB_TO_B(mp, buf_len_fsb),
532 end_size);
533
534 if (error) {
535 goto out_lock;
536 }
537
538 start_zero_fsb = imap.br_startoff + buf_len_fsb;
539 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
540
541 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
542 }
543
544 return 0;
545
546 out_lock:
547
548 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
549 ASSERT(error >= 0);
550 return error;
551 }
552
553 ssize_t /* bytes written, or (-) error */
554 xfs_write(
555 bhv_desc_t *bdp,
556 struct kiocb *iocb,
557 const struct iovec *iovp,
558 unsigned int nsegs,
559 loff_t *offset,
560 int ioflags,
561 cred_t *credp)
562 {
563 struct file *file = iocb->ki_filp;
564 struct address_space *mapping = file->f_mapping;
565 struct inode *inode = mapping->host;
566 unsigned long segs = nsegs;
567 xfs_inode_t *xip;
568 xfs_mount_t *mp;
569 ssize_t ret = 0, error = 0;
570 xfs_fsize_t isize, new_size;
571 xfs_iocore_t *io;
572 vnode_t *vp;
573 unsigned long seg;
574 int iolock;
575 int eventsent = 0;
576 vrwlock_t locktype;
577 size_t ocount = 0, count;
578 loff_t pos;
579 int need_i_mutex = 1, need_flush = 0;
580
581 XFS_STATS_INC(xs_write_calls);
582
583 vp = BHV_TO_VNODE(bdp);
584 xip = XFS_BHVTOI(bdp);
585
586 for (seg = 0; seg < segs; seg++) {
587 const struct iovec *iv = &iovp[seg];
588
589 /*
590 * If any segment has a negative length, or the cumulative
591 * length ever wraps negative then return -EINVAL.
592 */
593 ocount += iv->iov_len;
594 if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
595 return -EINVAL;
596 if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
597 continue;
598 if (seg == 0)
599 return -EFAULT;
600 segs = seg;
601 ocount -= iv->iov_len; /* This segment is no good */
602 break;
603 }
604
605 count = ocount;
606 pos = *offset;
607
608 if (count == 0)
609 return 0;
610
611 io = &xip->i_iocore;
612 mp = io->io_mount;
613
614 if (XFS_FORCED_SHUTDOWN(mp))
615 return -EIO;
616
617 fs_check_frozen(vp->v_vfsp, SB_FREEZE_WRITE);
618
619 if (ioflags & IO_ISDIRECT) {
620 xfs_buftarg_t *target =
621 (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
622 mp->m_rtdev_targp : mp->m_ddev_targp;
623
624 if ((pos & target->bt_smask) || (count & target->bt_smask))
625 return XFS_ERROR(-EINVAL);
626
627 if (!VN_CACHED(vp) && pos < i_size_read(inode))
628 need_i_mutex = 0;
629
630 if (VN_CACHED(vp))
631 need_flush = 1;
632 }
633
634 relock:
635 if (need_i_mutex) {
636 iolock = XFS_IOLOCK_EXCL;
637 locktype = VRWLOCK_WRITE;
638
639 mutex_lock(&inode->i_mutex);
640 } else {
641 iolock = XFS_IOLOCK_SHARED;
642 locktype = VRWLOCK_WRITE_DIRECT;
643 }
644
645 xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
646
647 isize = i_size_read(inode);
648
649 if (file->f_flags & O_APPEND)
650 *offset = isize;
651
652 start:
653 error = -generic_write_checks(file, &pos, &count,
654 S_ISBLK(inode->i_mode));
655 if (error) {
656 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
657 goto out_unlock_mutex;
658 }
659
660 new_size = pos + count;
661 if (new_size > isize)
662 io->io_new_size = new_size;
663
664 if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) &&
665 !(ioflags & IO_INVIS) && !eventsent)) {
666 loff_t savedsize = pos;
667 int dmflags = FILP_DELAY_FLAG(file);
668
669 if (need_i_mutex)
670 dmflags |= DM_FLAGS_IMUX;
671
672 xfs_iunlock(xip, XFS_ILOCK_EXCL);
673 error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp,
674 pos, count,
675 dmflags, &locktype);
676 if (error) {
677 xfs_iunlock(xip, iolock);
678 goto out_unlock_mutex;
679 }
680 xfs_ilock(xip, XFS_ILOCK_EXCL);
681 eventsent = 1;
682
683 /*
684 * The iolock was dropped and reacquired in XFS_SEND_DATA
685 * so we have to recheck the size when appending.
686 * We will only "goto start;" once, since having sent the
687 * event prevents another call to XFS_SEND_DATA, which is
688 * what allows the size to change in the first place.
689 */
690 if ((file->f_flags & O_APPEND) && savedsize != isize) {
691 pos = isize = xip->i_d.di_size;
692 goto start;
693 }
694 }
695
696 if (likely(!(ioflags & IO_INVIS))) {
697 file_update_time(file);
698 xfs_ichgtime_fast(xip, inode,
699 XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
700 }
701
702 /*
703 * If the offset is beyond the size of the file, we have a couple
704 * of things to do. First, if there is already space allocated
705 * we need to either create holes or zero the disk or ...
706 *
707 * If there is a page where the previous size lands, we need
708 * to zero it out up to the new size.
709 */
710
711 if (pos > isize) {
712 error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos,
713 isize, pos + count);
714 if (error) {
715 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
716 goto out_unlock_mutex;
717 }
718 }
719 xfs_iunlock(xip, XFS_ILOCK_EXCL);
720
721 /*
722 * If we're writing the file then make sure to clear the
723 * setuid and setgid bits if the process is not being run
724 * by root. This keeps people from modifying setuid and
725 * setgid binaries.
726 */
727
728 if (((xip->i_d.di_mode & S_ISUID) ||
729 ((xip->i_d.di_mode & (S_ISGID | S_IXGRP)) ==
730 (S_ISGID | S_IXGRP))) &&
731 !capable(CAP_FSETID)) {
732 error = xfs_write_clear_setuid(xip);
733 if (likely(!error))
734 error = -remove_suid(file->f_dentry);
735 if (unlikely(error)) {
736 xfs_iunlock(xip, iolock);
737 goto out_unlock_mutex;
738 }
739 }
740
741 retry:
742 /* We can write back this queue in page reclaim */
743 current->backing_dev_info = mapping->backing_dev_info;
744
745 if ((ioflags & IO_ISDIRECT)) {
746 if (need_flush) {
747 xfs_inval_cached_trace(io, pos, -1,
748 ctooff(offtoct(pos)), -1);
749 VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(pos)),
750 -1, FI_REMAPF_LOCKED);
751 }
752
753 if (need_i_mutex) {
754 /* demote the lock now the cached pages are gone */
755 XFS_ILOCK_DEMOTE(mp, io, XFS_IOLOCK_EXCL);
756 mutex_unlock(&inode->i_mutex);
757
758 iolock = XFS_IOLOCK_SHARED;
759 locktype = VRWLOCK_WRITE_DIRECT;
760 need_i_mutex = 0;
761 }
762
763 xfs_rw_enter_trace(XFS_DIOWR_ENTER, io, (void *)iovp, segs,
764 *offset, ioflags);
765 ret = generic_file_direct_write(iocb, iovp,
766 &segs, pos, offset, count, ocount);
767
768 /*
769 * direct-io write to a hole: fall through to buffered I/O
770 * for completing the rest of the request.
771 */
772 if (ret >= 0 && ret != count) {
773 XFS_STATS_ADD(xs_write_bytes, ret);
774
775 pos += ret;
776 count -= ret;
777
778 need_i_mutex = 1;
779 ioflags &= ~IO_ISDIRECT;
780 xfs_iunlock(xip, iolock);
781 goto relock;
782 }
783 } else {
784 xfs_rw_enter_trace(XFS_WRITE_ENTER, io, (void *)iovp, segs,
785 *offset, ioflags);
786 ret = generic_file_buffered_write(iocb, iovp, segs,
787 pos, offset, count, ret);
788 }
789
790 current->backing_dev_info = NULL;
791
792 if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
793 ret = wait_on_sync_kiocb(iocb);
794
795 if ((ret == -ENOSPC) &&
796 DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_NOSPACE) &&
797 !(ioflags & IO_INVIS)) {
798
799 xfs_rwunlock(bdp, locktype);
800 if (need_i_mutex)
801 mutex_unlock(&inode->i_mutex);
802 error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, vp,
803 DM_RIGHT_NULL, vp, DM_RIGHT_NULL, NULL, NULL,
804 0, 0, 0); /* Delay flag intentionally unused */
805 if (error)
806 goto out_nounlocks;
807 if (need_i_mutex)
808 mutex_lock(&inode->i_mutex);
809 xfs_rwlock(bdp, locktype);
810 pos = xip->i_d.di_size;
811 ret = 0;
812 goto retry;
813 }
814
815 isize = i_size_read(inode);
816 if (unlikely(ret < 0 && ret != -EFAULT && *offset > isize))
817 *offset = isize;
818
819 if (*offset > xip->i_d.di_size) {
820 xfs_ilock(xip, XFS_ILOCK_EXCL);
821 if (*offset > xip->i_d.di_size) {
822 xip->i_d.di_size = *offset;
823 i_size_write(inode, *offset);
824 xip->i_update_core = 1;
825 xip->i_update_size = 1;
826 }
827 xfs_iunlock(xip, XFS_ILOCK_EXCL);
828 }
829
830 error = -ret;
831 if (ret <= 0)
832 goto out_unlock_internal;
833
834 XFS_STATS_ADD(xs_write_bytes, ret);
835
836 /* Handle various SYNC-type writes */
837 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
838 /*
839 * If we're treating this as O_DSYNC and we have not updated the
840 * size, force the log.
841 */
842 if (!(mp->m_flags & XFS_MOUNT_OSYNCISOSYNC) &&
843 !(xip->i_update_size)) {
844 xfs_inode_log_item_t *iip = xip->i_itemp;
845
846 /*
847 * If an allocation transaction occurred
848 * without extending the size, then we have to force
849 * the log up the proper point to ensure that the
850 * allocation is permanent. We can't count on
851 * the fact that buffered writes lock out direct I/O
852 * writes - the direct I/O write could have extended
853 * the size nontransactionally, then finished before
854 * we started. xfs_write_file will think that the file
855 * didn't grow but the update isn't safe unless the
856 * size change is logged.
857 *
858 * Force the log if we've committed a transaction
859 * against the inode or if someone else has and
860 * the commit record hasn't gone to disk (e.g.
861 * the inode is pinned). This guarantees that
862 * all changes affecting the inode are permanent
863 * when we return.
864 */
865 if (iip && iip->ili_last_lsn) {
866 xfs_log_force(mp, iip->ili_last_lsn,
867 XFS_LOG_FORCE | XFS_LOG_SYNC);
868 } else if (xfs_ipincount(xip) > 0) {
869 xfs_log_force(mp, (xfs_lsn_t)0,
870 XFS_LOG_FORCE | XFS_LOG_SYNC);
871 }
872
873 } else {
874 xfs_trans_t *tp;
875
876 /*
877 * O_SYNC or O_DSYNC _with_ a size update are handled
878 * the same way.
879 *
880 * If the write was synchronous then we need to make
881 * sure that the inode modification time is permanent.
882 * We'll have updated the timestamp above, so here
883 * we use a synchronous transaction to log the inode.
884 * It's not fast, but it's necessary.
885 *
886 * If this a dsync write and the size got changed
887 * non-transactionally, then we need to ensure that
888 * the size change gets logged in a synchronous
889 * transaction.
890 */
891
892 tp = xfs_trans_alloc(mp, XFS_TRANS_WRITE_SYNC);
893 if ((error = xfs_trans_reserve(tp, 0,
894 XFS_SWRITE_LOG_RES(mp),
895 0, 0, 0))) {
896 /* Transaction reserve failed */
897 xfs_trans_cancel(tp, 0);
898 } else {
899 /* Transaction reserve successful */
900 xfs_ilock(xip, XFS_ILOCK_EXCL);
901 xfs_trans_ijoin(tp, xip, XFS_ILOCK_EXCL);
902 xfs_trans_ihold(tp, xip);
903 xfs_trans_log_inode(tp, xip, XFS_ILOG_CORE);
904 xfs_trans_set_sync(tp);
905 error = xfs_trans_commit(tp, 0, NULL);
906 xfs_iunlock(xip, XFS_ILOCK_EXCL);
907 }
908 if (error)
909 goto out_unlock_internal;
910 }
911
912 xfs_rwunlock(bdp, locktype);
913 if (need_i_mutex)
914 mutex_unlock(&inode->i_mutex);
915
916 error = sync_page_range(inode, mapping, pos, ret);
917 if (!error)
918 error = ret;
919 return error;
920 }
921
922 out_unlock_internal:
923 xfs_rwunlock(bdp, locktype);
924 out_unlock_mutex:
925 if (need_i_mutex)
926 mutex_unlock(&inode->i_mutex);
927 out_nounlocks:
928 return -error;
929 }
930
931 /*
932 * All xfs metadata buffers except log state machine buffers
933 * get this attached as their b_bdstrat callback function.
934 * This is so that we can catch a buffer
935 * after prematurely unpinning it to forcibly shutdown the filesystem.
936 */
937 int
938 xfs_bdstrat_cb(struct xfs_buf *bp)
939 {
940 xfs_mount_t *mp;
941
942 mp = XFS_BUF_FSPRIVATE3(bp, xfs_mount_t *);
943 if (!XFS_FORCED_SHUTDOWN(mp)) {
944 xfs_buf_iorequest(bp);
945 return 0;
946 } else {
947 xfs_buftrace("XFS__BDSTRAT IOERROR", bp);
948 /*
949 * Metadata write that didn't get logged but
950 * written delayed anyway. These aren't associated
951 * with a transaction, and can be ignored.
952 */
953 if (XFS_BUF_IODONE_FUNC(bp) == NULL &&
954 (XFS_BUF_ISREAD(bp)) == 0)
955 return (xfs_bioerror_relse(bp));
956 else
957 return (xfs_bioerror(bp));
958 }
959 }
960
961
962 int
963 xfs_bmap(bhv_desc_t *bdp,
964 xfs_off_t offset,
965 ssize_t count,
966 int flags,
967 xfs_iomap_t *iomapp,
968 int *niomaps)
969 {
970 xfs_inode_t *ip = XFS_BHVTOI(bdp);
971 xfs_iocore_t *io = &ip->i_iocore;
972
973 ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
974 ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
975 ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
976
977 return xfs_iomap(io, offset, count, flags, iomapp, niomaps);
978 }
979
980 /*
981 * Wrapper around bdstrat so that we can stop data
982 * from going to disk in case we are shutting down the filesystem.
983 * Typically user data goes thru this path; one of the exceptions
984 * is the superblock.
985 */
986 int
987 xfsbdstrat(
988 struct xfs_mount *mp,
989 struct xfs_buf *bp)
990 {
991 ASSERT(mp);
992 if (!XFS_FORCED_SHUTDOWN(mp)) {
993 /* Grio redirection would go here
994 * if (XFS_BUF_IS_GRIO(bp)) {
995 */
996
997 xfs_buf_iorequest(bp);
998 return 0;
999 }
1000
1001 xfs_buftrace("XFSBDSTRAT IOERROR", bp);
1002 return (xfs_bioerror_relse(bp));
1003 }
1004
1005 /*
1006 * If the underlying (data/log/rt) device is readonly, there are some
1007 * operations that cannot proceed.
1008 */
1009 int
1010 xfs_dev_is_read_only(
1011 xfs_mount_t *mp,
1012 char *message)
1013 {
1014 if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1015 xfs_readonly_buftarg(mp->m_logdev_targp) ||
1016 (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1017 cmn_err(CE_NOTE,
1018 "XFS: %s required on read-only device.", message);
1019 cmn_err(CE_NOTE,
1020 "XFS: write access unavailable, cannot proceed.");
1021 return EROFS;
1022 }
1023 return 0;
1024 }
Linux kernel - Deliverables
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