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[mirror_ubuntu-focal-kernel.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 *)NULL,
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 *)NULL,
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->pbr_smask) ||
237 (size & target->pbr_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
256 if (unlikely(ioflags & IO_ISDIRECT))
257 mutex_lock(&inode->i_mutex);
258 xfs_ilock(ip, XFS_IOLOCK_SHARED);
259
260 if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
261 !(ioflags & IO_INVIS)) {
262 vrwlock_t locktype = VRWLOCK_READ;
263 int dmflags = FILP_DELAY_FLAG(file) | DM_SEM_FLAG_RD(ioflags);
264
265 ret = -XFS_SEND_DATA(mp, DM_EVENT_READ,
266 BHV_TO_VNODE(bdp), *offset, size,
267 dmflags, &locktype);
268 if (ret) {
269 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
270 goto unlock_isem;
271 }
272 }
273
274 xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,
275 (void *)iovp, segs, *offset, ioflags);
276 ret = __generic_file_aio_read(iocb, iovp, segs, offset);
277 if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
278 ret = wait_on_sync_kiocb(iocb);
279 if (ret > 0)
280 XFS_STATS_ADD(xs_read_bytes, ret);
281
282 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
283
284 if (likely(!(ioflags & IO_INVIS)))
285 xfs_ichgtime_fast(ip, inode, XFS_ICHGTIME_ACC);
286
287 unlock_isem:
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 if (likely(!(ioflags & IO_INVIS)))
350 xfs_ichgtime_fast(ip, LINVFS_GET_IP(vp), XFS_ICHGTIME_ACC);
351
352 return ret;
353 }
354
355 /*
356 * This routine is called to handle zeroing any space in the last
357 * block of the file that is beyond the EOF. We do this since the
358 * size is being increased without writing anything to that block
359 * and we don't want anyone to read the garbage on the disk.
360 */
361 STATIC int /* error (positive) */
362 xfs_zero_last_block(
363 struct inode *ip,
364 xfs_iocore_t *io,
365 xfs_off_t offset,
366 xfs_fsize_t isize,
367 xfs_fsize_t end_size)
368 {
369 xfs_fileoff_t last_fsb;
370 xfs_mount_t *mp;
371 int nimaps;
372 int zero_offset;
373 int zero_len;
374 int isize_fsb_offset;
375 int error = 0;
376 xfs_bmbt_irec_t imap;
377 loff_t loff;
378 size_t lsize;
379
380 ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
381 ASSERT(offset > isize);
382
383 mp = io->io_mount;
384
385 isize_fsb_offset = XFS_B_FSB_OFFSET(mp, isize);
386 if (isize_fsb_offset == 0) {
387 /*
388 * There are no extra bytes in the last block on disk to
389 * zero, so return.
390 */
391 return 0;
392 }
393
394 last_fsb = XFS_B_TO_FSBT(mp, isize);
395 nimaps = 1;
396 error = XFS_BMAPI(mp, NULL, io, last_fsb, 1, 0, NULL, 0, &imap,
397 &nimaps, NULL);
398 if (error) {
399 return error;
400 }
401 ASSERT(nimaps > 0);
402 /*
403 * If the block underlying isize is just a hole, then there
404 * is nothing to zero.
405 */
406 if (imap.br_startblock == HOLESTARTBLOCK) {
407 return 0;
408 }
409 /*
410 * Zero the part of the last block beyond the EOF, and write it
411 * out sync. We need to drop the ilock while we do this so we
412 * don't deadlock when the buffer cache calls back to us.
413 */
414 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
415 loff = XFS_FSB_TO_B(mp, last_fsb);
416 lsize = XFS_FSB_TO_B(mp, 1);
417
418 zero_offset = isize_fsb_offset;
419 zero_len = mp->m_sb.sb_blocksize - isize_fsb_offset;
420
421 error = xfs_iozero(ip, loff + zero_offset, zero_len, end_size);
422
423 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
424 ASSERT(error >= 0);
425 return error;
426 }
427
428 /*
429 * Zero any on disk space between the current EOF and the new,
430 * larger EOF. This handles the normal case of zeroing the remainder
431 * of the last block in the file and the unusual case of zeroing blocks
432 * out beyond the size of the file. This second case only happens
433 * with fixed size extents and when the system crashes before the inode
434 * size was updated but after blocks were allocated. If fill is set,
435 * then any holes in the range are filled and zeroed. If not, the holes
436 * are left alone as holes.
437 */
438
439 int /* error (positive) */
440 xfs_zero_eof(
441 vnode_t *vp,
442 xfs_iocore_t *io,
443 xfs_off_t offset, /* starting I/O offset */
444 xfs_fsize_t isize, /* current inode size */
445 xfs_fsize_t end_size) /* terminal inode size */
446 {
447 struct inode *ip = LINVFS_GET_IP(vp);
448 xfs_fileoff_t start_zero_fsb;
449 xfs_fileoff_t end_zero_fsb;
450 xfs_fileoff_t prev_zero_fsb;
451 xfs_fileoff_t zero_count_fsb;
452 xfs_fileoff_t last_fsb;
453 xfs_extlen_t buf_len_fsb;
454 xfs_extlen_t prev_zero_count;
455 xfs_mount_t *mp;
456 int nimaps;
457 int error = 0;
458 xfs_bmbt_irec_t imap;
459 loff_t loff;
460 size_t lsize;
461
462 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
463 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
464
465 mp = io->io_mount;
466
467 /*
468 * First handle zeroing the block on which isize resides.
469 * We only zero a part of that block so it is handled specially.
470 */
471 error = xfs_zero_last_block(ip, io, offset, isize, end_size);
472 if (error) {
473 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
474 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
475 return error;
476 }
477
478 /*
479 * Calculate the range between the new size and the old
480 * where blocks needing to be zeroed may exist. To get the
481 * block where the last byte in the file currently resides,
482 * we need to subtract one from the size and truncate back
483 * to a block boundary. We subtract 1 in case the size is
484 * exactly on a block boundary.
485 */
486 last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
487 start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
488 end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
489 ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
490 if (last_fsb == end_zero_fsb) {
491 /*
492 * The size was only incremented on its last block.
493 * We took care of that above, so just return.
494 */
495 return 0;
496 }
497
498 ASSERT(start_zero_fsb <= end_zero_fsb);
499 prev_zero_fsb = NULLFILEOFF;
500 prev_zero_count = 0;
501 while (start_zero_fsb <= end_zero_fsb) {
502 nimaps = 1;
503 zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
504 error = XFS_BMAPI(mp, NULL, io, start_zero_fsb, zero_count_fsb,
505 0, NULL, 0, &imap, &nimaps, NULL);
506 if (error) {
507 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
508 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
509 return error;
510 }
511 ASSERT(nimaps > 0);
512
513 if (imap.br_state == XFS_EXT_UNWRITTEN ||
514 imap.br_startblock == HOLESTARTBLOCK) {
515 /*
516 * This loop handles initializing pages that were
517 * partially initialized by the code below this
518 * loop. It basically zeroes the part of the page
519 * that sits on a hole and sets the page as P_HOLE
520 * and calls remapf if it is a mapped file.
521 */
522 prev_zero_fsb = NULLFILEOFF;
523 prev_zero_count = 0;
524 start_zero_fsb = imap.br_startoff +
525 imap.br_blockcount;
526 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
527 continue;
528 }
529
530 /*
531 * There are blocks in the range requested.
532 * Zero them a single write at a time. We actually
533 * don't zero the entire range returned if it is
534 * too big and simply loop around to get the rest.
535 * That is not the most efficient thing to do, but it
536 * is simple and this path should not be exercised often.
537 */
538 buf_len_fsb = XFS_FILBLKS_MIN(imap.br_blockcount,
539 mp->m_writeio_blocks << 8);
540 /*
541 * Drop the inode lock while we're doing the I/O.
542 * We'll still have the iolock to protect us.
543 */
544 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
545
546 loff = XFS_FSB_TO_B(mp, start_zero_fsb);
547 lsize = XFS_FSB_TO_B(mp, buf_len_fsb);
548
549 error = xfs_iozero(ip, loff, lsize, end_size);
550
551 if (error) {
552 goto out_lock;
553 }
554
555 prev_zero_fsb = start_zero_fsb;
556 prev_zero_count = buf_len_fsb;
557 start_zero_fsb = imap.br_startoff + buf_len_fsb;
558 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
559
560 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
561 }
562
563 return 0;
564
565 out_lock:
566
567 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
568 ASSERT(error >= 0);
569 return error;
570 }
571
572 ssize_t /* bytes written, or (-) error */
573 xfs_write(
574 bhv_desc_t *bdp,
575 struct kiocb *iocb,
576 const struct iovec *iovp,
577 unsigned int nsegs,
578 loff_t *offset,
579 int ioflags,
580 cred_t *credp)
581 {
582 struct file *file = iocb->ki_filp;
583 struct address_space *mapping = file->f_mapping;
584 struct inode *inode = mapping->host;
585 unsigned long segs = nsegs;
586 xfs_inode_t *xip;
587 xfs_mount_t *mp;
588 ssize_t ret = 0, error = 0;
589 xfs_fsize_t isize, new_size;
590 xfs_iocore_t *io;
591 vnode_t *vp;
592 unsigned long seg;
593 int iolock;
594 int eventsent = 0;
595 vrwlock_t locktype;
596 size_t ocount = 0, count;
597 loff_t pos;
598 int need_isem = 1, need_flush = 0;
599
600 XFS_STATS_INC(xs_write_calls);
601
602 vp = BHV_TO_VNODE(bdp);
603 xip = XFS_BHVTOI(bdp);
604
605 for (seg = 0; seg < segs; seg++) {
606 const struct iovec *iv = &iovp[seg];
607
608 /*
609 * If any segment has a negative length, or the cumulative
610 * length ever wraps negative then return -EINVAL.
611 */
612 ocount += iv->iov_len;
613 if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
614 return -EINVAL;
615 if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
616 continue;
617 if (seg == 0)
618 return -EFAULT;
619 segs = seg;
620 ocount -= iv->iov_len; /* This segment is no good */
621 break;
622 }
623
624 count = ocount;
625 pos = *offset;
626
627 if (count == 0)
628 return 0;
629
630 io = &xip->i_iocore;
631 mp = io->io_mount;
632
633 if (XFS_FORCED_SHUTDOWN(mp))
634 return -EIO;
635
636 fs_check_frozen(vp->v_vfsp, SB_FREEZE_WRITE);
637
638 if (ioflags & IO_ISDIRECT) {
639 xfs_buftarg_t *target =
640 (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
641 mp->m_rtdev_targp : mp->m_ddev_targp;
642
643 if ((pos & target->pbr_smask) || (count & target->pbr_smask))
644 return XFS_ERROR(-EINVAL);
645
646 if (!VN_CACHED(vp) && pos < i_size_read(inode))
647 need_isem = 0;
648
649 if (VN_CACHED(vp))
650 need_flush = 1;
651 }
652
653 relock:
654 if (need_isem) {
655 iolock = XFS_IOLOCK_EXCL;
656 locktype = VRWLOCK_WRITE;
657
658 mutex_lock(&inode->i_mutex);
659 } else {
660 iolock = XFS_IOLOCK_SHARED;
661 locktype = VRWLOCK_WRITE_DIRECT;
662 }
663
664 xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
665
666 isize = i_size_read(inode);
667
668 if (file->f_flags & O_APPEND)
669 *offset = isize;
670
671 start:
672 error = -generic_write_checks(file, &pos, &count,
673 S_ISBLK(inode->i_mode));
674 if (error) {
675 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
676 goto out_unlock_isem;
677 }
678
679 new_size = pos + count;
680 if (new_size > isize)
681 io->io_new_size = new_size;
682
683 if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) &&
684 !(ioflags & IO_INVIS) && !eventsent)) {
685 loff_t savedsize = pos;
686 int dmflags = FILP_DELAY_FLAG(file);
687
688 if (need_isem)
689 dmflags |= DM_FLAGS_IMUX;
690
691 xfs_iunlock(xip, XFS_ILOCK_EXCL);
692 error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp,
693 pos, count,
694 dmflags, &locktype);
695 if (error) {
696 xfs_iunlock(xip, iolock);
697 goto out_unlock_isem;
698 }
699 xfs_ilock(xip, XFS_ILOCK_EXCL);
700 eventsent = 1;
701
702 /*
703 * The iolock was dropped and reaquired in XFS_SEND_DATA
704 * so we have to recheck the size when appending.
705 * We will only "goto start;" once, since having sent the
706 * event prevents another call to XFS_SEND_DATA, which is
707 * what allows the size to change in the first place.
708 */
709 if ((file->f_flags & O_APPEND) && savedsize != isize) {
710 pos = isize = xip->i_d.di_size;
711 goto start;
712 }
713 }
714
715 if (likely(!(ioflags & IO_INVIS))) {
716 inode_update_time(inode, 1);
717 xfs_ichgtime_fast(xip, inode,
718 XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
719 }
720
721 /*
722 * If the offset is beyond the size of the file, we have a couple
723 * of things to do. First, if there is already space allocated
724 * we need to either create holes or zero the disk or ...
725 *
726 * If there is a page where the previous size lands, we need
727 * to zero it out up to the new size.
728 */
729
730 if (pos > isize) {
731 error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos,
732 isize, pos + count);
733 if (error) {
734 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
735 goto out_unlock_isem;
736 }
737 }
738 xfs_iunlock(xip, XFS_ILOCK_EXCL);
739
740 /*
741 * If we're writing the file then make sure to clear the
742 * setuid and setgid bits if the process is not being run
743 * by root. This keeps people from modifying setuid and
744 * setgid binaries.
745 */
746
747 if (((xip->i_d.di_mode & S_ISUID) ||
748 ((xip->i_d.di_mode & (S_ISGID | S_IXGRP)) ==
749 (S_ISGID | S_IXGRP))) &&
750 !capable(CAP_FSETID)) {
751 error = xfs_write_clear_setuid(xip);
752 if (likely(!error))
753 error = -remove_suid(file->f_dentry);
754 if (unlikely(error)) {
755 xfs_iunlock(xip, iolock);
756 goto out_unlock_isem;
757 }
758 }
759
760 retry:
761 /* We can write back this queue in page reclaim */
762 current->backing_dev_info = mapping->backing_dev_info;
763
764 if ((ioflags & IO_ISDIRECT)) {
765 if (need_flush) {
766 xfs_inval_cached_trace(io, pos, -1,
767 ctooff(offtoct(pos)), -1);
768 VOP_FLUSHINVAL_PAGES(vp, ctooff(offtoct(pos)),
769 -1, FI_REMAPF_LOCKED);
770 }
771
772 if (need_isem) {
773 /* demote the lock now the cached pages are gone */
774 XFS_ILOCK_DEMOTE(mp, io, XFS_IOLOCK_EXCL);
775 mutex_unlock(&inode->i_mutex);
776
777 iolock = XFS_IOLOCK_SHARED;
778 locktype = VRWLOCK_WRITE_DIRECT;
779 need_isem = 0;
780 }
781
782 xfs_rw_enter_trace(XFS_DIOWR_ENTER, io, (void *)iovp, segs,
783 *offset, ioflags);
784 ret = generic_file_direct_write(iocb, iovp,
785 &segs, pos, offset, count, ocount);
786
787 /*
788 * direct-io write to a hole: fall through to buffered I/O
789 * for completing the rest of the request.
790 */
791 if (ret >= 0 && ret != count) {
792 XFS_STATS_ADD(xs_write_bytes, ret);
793
794 pos += ret;
795 count -= ret;
796
797 need_isem = 1;
798 ioflags &= ~IO_ISDIRECT;
799 xfs_iunlock(xip, iolock);
800 goto relock;
801 }
802 } else {
803 xfs_rw_enter_trace(XFS_WRITE_ENTER, io, (void *)iovp, segs,
804 *offset, ioflags);
805 ret = generic_file_buffered_write(iocb, iovp, segs,
806 pos, offset, count, ret);
807 }
808
809 current->backing_dev_info = NULL;
810
811 if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
812 ret = wait_on_sync_kiocb(iocb);
813
814 if ((ret == -ENOSPC) &&
815 DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_NOSPACE) &&
816 !(ioflags & IO_INVIS)) {
817
818 xfs_rwunlock(bdp, locktype);
819 if (need_isem)
820 mutex_unlock(&inode->i_mutex);
821 error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, vp,
822 DM_RIGHT_NULL, vp, DM_RIGHT_NULL, NULL, NULL,
823 0, 0, 0); /* Delay flag intentionally unused */
824 if (error)
825 goto out_nounlocks;
826 if (need_isem)
827 mutex_lock(&inode->i_mutex);
828 xfs_rwlock(bdp, locktype);
829 pos = xip->i_d.di_size;
830 ret = 0;
831 goto retry;
832 }
833
834 if (*offset > xip->i_d.di_size) {
835 xfs_ilock(xip, XFS_ILOCK_EXCL);
836 if (*offset > xip->i_d.di_size) {
837 xip->i_d.di_size = *offset;
838 i_size_write(inode, *offset);
839 xip->i_update_core = 1;
840 xip->i_update_size = 1;
841 }
842 xfs_iunlock(xip, XFS_ILOCK_EXCL);
843 }
844
845 error = -ret;
846 if (ret <= 0)
847 goto out_unlock_internal;
848
849 XFS_STATS_ADD(xs_write_bytes, ret);
850
851 /* Handle various SYNC-type writes */
852 if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
853 /*
854 * If we're treating this as O_DSYNC and we have not updated the
855 * size, force the log.
856 */
857 if (!(mp->m_flags & XFS_MOUNT_OSYNCISOSYNC) &&
858 !(xip->i_update_size)) {
859 xfs_inode_log_item_t *iip = xip->i_itemp;
860
861 /*
862 * If an allocation transaction occurred
863 * without extending the size, then we have to force
864 * the log up the proper point to ensure that the
865 * allocation is permanent. We can't count on
866 * the fact that buffered writes lock out direct I/O
867 * writes - the direct I/O write could have extended
868 * the size nontransactionally, then finished before
869 * we started. xfs_write_file will think that the file
870 * didn't grow but the update isn't safe unless the
871 * size change is logged.
872 *
873 * Force the log if we've committed a transaction
874 * against the inode or if someone else has and
875 * the commit record hasn't gone to disk (e.g.
876 * the inode is pinned). This guarantees that
877 * all changes affecting the inode are permanent
878 * when we return.
879 */
880 if (iip && iip->ili_last_lsn) {
881 xfs_log_force(mp, iip->ili_last_lsn,
882 XFS_LOG_FORCE | XFS_LOG_SYNC);
883 } else if (xfs_ipincount(xip) > 0) {
884 xfs_log_force(mp, (xfs_lsn_t)0,
885 XFS_LOG_FORCE | XFS_LOG_SYNC);
886 }
887
888 } else {
889 xfs_trans_t *tp;
890
891 /*
892 * O_SYNC or O_DSYNC _with_ a size update are handled
893 * the same way.
894 *
895 * If the write was synchronous then we need to make
896 * sure that the inode modification time is permanent.
897 * We'll have updated the timestamp above, so here
898 * we use a synchronous transaction to log the inode.
899 * It's not fast, but it's necessary.
900 *
901 * If this a dsync write and the size got changed
902 * non-transactionally, then we need to ensure that
903 * the size change gets logged in a synchronous
904 * transaction.
905 */
906
907 tp = xfs_trans_alloc(mp, XFS_TRANS_WRITE_SYNC);
908 if ((error = xfs_trans_reserve(tp, 0,
909 XFS_SWRITE_LOG_RES(mp),
910 0, 0, 0))) {
911 /* Transaction reserve failed */
912 xfs_trans_cancel(tp, 0);
913 } else {
914 /* Transaction reserve successful */
915 xfs_ilock(xip, XFS_ILOCK_EXCL);
916 xfs_trans_ijoin(tp, xip, XFS_ILOCK_EXCL);
917 xfs_trans_ihold(tp, xip);
918 xfs_trans_log_inode(tp, xip, XFS_ILOG_CORE);
919 xfs_trans_set_sync(tp);
920 error = xfs_trans_commit(tp, 0, NULL);
921 xfs_iunlock(xip, XFS_ILOCK_EXCL);
922 }
923 if (error)
924 goto out_unlock_internal;
925 }
926
927 xfs_rwunlock(bdp, locktype);
928 if (need_isem)
929 mutex_unlock(&inode->i_mutex);
930
931 error = sync_page_range(inode, mapping, pos, ret);
932 if (!error)
933 error = ret;
934 return error;
935 }
936
937 out_unlock_internal:
938 xfs_rwunlock(bdp, locktype);
939 out_unlock_isem:
940 if (need_isem)
941 mutex_unlock(&inode->i_mutex);
942 out_nounlocks:
943 return -error;
944 }
945
946 /*
947 * All xfs metadata buffers except log state machine buffers
948 * get this attached as their b_bdstrat callback function.
949 * This is so that we can catch a buffer
950 * after prematurely unpinning it to forcibly shutdown the filesystem.
951 */
952 int
953 xfs_bdstrat_cb(struct xfs_buf *bp)
954 {
955 xfs_mount_t *mp;
956
957 mp = XFS_BUF_FSPRIVATE3(bp, xfs_mount_t *);
958 if (!XFS_FORCED_SHUTDOWN(mp)) {
959 pagebuf_iorequest(bp);
960 return 0;
961 } else {
962 xfs_buftrace("XFS__BDSTRAT IOERROR", bp);
963 /*
964 * Metadata write that didn't get logged but
965 * written delayed anyway. These aren't associated
966 * with a transaction, and can be ignored.
967 */
968 if (XFS_BUF_IODONE_FUNC(bp) == NULL &&
969 (XFS_BUF_ISREAD(bp)) == 0)
970 return (xfs_bioerror_relse(bp));
971 else
972 return (xfs_bioerror(bp));
973 }
974 }
975
976
977 int
978 xfs_bmap(bhv_desc_t *bdp,
979 xfs_off_t offset,
980 ssize_t count,
981 int flags,
982 xfs_iomap_t *iomapp,
983 int *niomaps)
984 {
985 xfs_inode_t *ip = XFS_BHVTOI(bdp);
986 xfs_iocore_t *io = &ip->i_iocore;
987
988 ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
989 ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
990 ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
991
992 return xfs_iomap(io, offset, count, flags, iomapp, niomaps);
993 }
994
995 /*
996 * Wrapper around bdstrat so that we can stop data
997 * from going to disk in case we are shutting down the filesystem.
998 * Typically user data goes thru this path; one of the exceptions
999 * is the superblock.
1000 */
1001 int
1002 xfsbdstrat(
1003 struct xfs_mount *mp,
1004 struct xfs_buf *bp)
1005 {
1006 ASSERT(mp);
1007 if (!XFS_FORCED_SHUTDOWN(mp)) {
1008 /* Grio redirection would go here
1009 * if (XFS_BUF_IS_GRIO(bp)) {
1010 */
1011
1012 pagebuf_iorequest(bp);
1013 return 0;
1014 }
1015
1016 xfs_buftrace("XFSBDSTRAT IOERROR", bp);
1017 return (xfs_bioerror_relse(bp));
1018 }
1019
1020 /*
1021 * If the underlying (data/log/rt) device is readonly, there are some
1022 * operations that cannot proceed.
1023 */
1024 int
1025 xfs_dev_is_read_only(
1026 xfs_mount_t *mp,
1027 char *message)
1028 {
1029 if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1030 xfs_readonly_buftarg(mp->m_logdev_targp) ||
1031 (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1032 cmn_err(CE_NOTE,
1033 "XFS: %s required on read-only device.", message);
1034 cmn_err(CE_NOTE,
1035 "XFS: write access unavailable, cannot proceed.");
1036 return EROFS;
1037 }
1038 return 0;
1039 }
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