xref: /linux/fs/xfs/xfs_iomap.c (revision d67b569f5f620c0fb95d5212642746b7ba9d29e4)
1 /*
2  * Copyright (c) 2000-2004 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 #include "xfs.h"
34 
35 #include "xfs_fs.h"
36 #include "xfs_inum.h"
37 #include "xfs_log.h"
38 #include "xfs_trans.h"
39 #include "xfs_sb.h"
40 #include "xfs_ag.h"
41 #include "xfs_dir.h"
42 #include "xfs_dir2.h"
43 #include "xfs_alloc.h"
44 #include "xfs_dmapi.h"
45 #include "xfs_quota.h"
46 #include "xfs_mount.h"
47 #include "xfs_alloc_btree.h"
48 #include "xfs_bmap_btree.h"
49 #include "xfs_ialloc_btree.h"
50 #include "xfs_btree.h"
51 #include "xfs_ialloc.h"
52 #include "xfs_attr_sf.h"
53 #include "xfs_dir_sf.h"
54 #include "xfs_dir2_sf.h"
55 #include "xfs_dinode.h"
56 #include "xfs_inode.h"
57 #include "xfs_bmap.h"
58 #include "xfs_bit.h"
59 #include "xfs_rtalloc.h"
60 #include "xfs_error.h"
61 #include "xfs_itable.h"
62 #include "xfs_rw.h"
63 #include "xfs_acl.h"
64 #include "xfs_cap.h"
65 #include "xfs_mac.h"
66 #include "xfs_attr.h"
67 #include "xfs_buf_item.h"
68 #include "xfs_trans_space.h"
69 #include "xfs_utils.h"
70 #include "xfs_iomap.h"
71 
72 #if defined(XFS_RW_TRACE)
73 void
74 xfs_iomap_enter_trace(
75 	int		tag,
76 	xfs_iocore_t	*io,
77 	xfs_off_t	offset,
78 	ssize_t		count)
79 {
80 	xfs_inode_t	*ip = XFS_IO_INODE(io);
81 
82 	if (!ip->i_rwtrace)
83 		return;
84 
85 	ktrace_enter(ip->i_rwtrace,
86 		(void *)((unsigned long)tag),
87 		(void *)ip,
88 		(void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
89 		(void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
90 		(void *)((unsigned long)((offset >> 32) & 0xffffffff)),
91 		(void *)((unsigned long)(offset & 0xffffffff)),
92 		(void *)((unsigned long)count),
93 		(void *)((unsigned long)((io->io_new_size >> 32) & 0xffffffff)),
94 		(void *)((unsigned long)(io->io_new_size & 0xffffffff)),
95 		(void *)NULL,
96 		(void *)NULL,
97 		(void *)NULL,
98 		(void *)NULL,
99 		(void *)NULL,
100 		(void *)NULL,
101 		(void *)NULL);
102 }
103 
104 void
105 xfs_iomap_map_trace(
106 	int		tag,
107 	xfs_iocore_t	*io,
108 	xfs_off_t	offset,
109 	ssize_t		count,
110 	xfs_iomap_t	*iomapp,
111 	xfs_bmbt_irec_t	*imapp,
112 	int		flags)
113 {
114 	xfs_inode_t	*ip = XFS_IO_INODE(io);
115 
116 	if (!ip->i_rwtrace)
117 		return;
118 
119 	ktrace_enter(ip->i_rwtrace,
120 		(void *)((unsigned long)tag),
121 		(void *)ip,
122 		(void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
123 		(void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
124 		(void *)((unsigned long)((offset >> 32) & 0xffffffff)),
125 		(void *)((unsigned long)(offset & 0xffffffff)),
126 		(void *)((unsigned long)count),
127 		(void *)((unsigned long)flags),
128 		(void *)((unsigned long)((iomapp->iomap_offset >> 32) & 0xffffffff)),
129 		(void *)((unsigned long)(iomapp->iomap_offset & 0xffffffff)),
130 		(void *)((unsigned long)(iomapp->iomap_delta)),
131 		(void *)((unsigned long)(iomapp->iomap_bsize)),
132 		(void *)((unsigned long)(iomapp->iomap_bn)),
133 		(void *)(__psint_t)(imapp->br_startoff),
134 		(void *)((unsigned long)(imapp->br_blockcount)),
135 		(void *)(__psint_t)(imapp->br_startblock));
136 }
137 #else
138 #define xfs_iomap_enter_trace(tag, io, offset, count)
139 #define xfs_iomap_map_trace(tag, io, offset, count, iomapp, imapp, flags)
140 #endif
141 
142 #define XFS_WRITEIO_ALIGN(mp,off)	(((off) >> mp->m_writeio_log) \
143 						<< mp->m_writeio_log)
144 #define XFS_STRAT_WRITE_IMAPS	2
145 #define XFS_WRITE_IMAPS		XFS_BMAP_MAX_NMAP
146 
147 STATIC int
148 xfs_imap_to_bmap(
149 	xfs_iocore_t	*io,
150 	xfs_off_t	offset,
151 	xfs_bmbt_irec_t *imap,
152 	xfs_iomap_t	*iomapp,
153 	int		imaps,			/* Number of imap entries */
154 	int		iomaps,			/* Number of iomap entries */
155 	int		flags)
156 {
157 	xfs_mount_t	*mp;
158 	xfs_fsize_t	nisize;
159 	int		pbm;
160 	xfs_fsblock_t	start_block;
161 
162 	mp = io->io_mount;
163 	nisize = XFS_SIZE(mp, io);
164 	if (io->io_new_size > nisize)
165 		nisize = io->io_new_size;
166 
167 	for (pbm = 0; imaps && pbm < iomaps; imaps--, iomapp++, imap++, pbm++) {
168 		iomapp->iomap_offset = XFS_FSB_TO_B(mp, imap->br_startoff);
169 		iomapp->iomap_delta = offset - iomapp->iomap_offset;
170 		iomapp->iomap_bsize = XFS_FSB_TO_B(mp, imap->br_blockcount);
171 		iomapp->iomap_flags = flags;
172 
173 		if (io->io_flags & XFS_IOCORE_RT) {
174 			iomapp->iomap_flags |= IOMAP_REALTIME;
175 			iomapp->iomap_target = mp->m_rtdev_targp;
176 		} else {
177 			iomapp->iomap_target = mp->m_ddev_targp;
178 		}
179 		start_block = imap->br_startblock;
180 		if (start_block == HOLESTARTBLOCK) {
181 			iomapp->iomap_bn = IOMAP_DADDR_NULL;
182 			iomapp->iomap_flags |= IOMAP_HOLE;
183 		} else if (start_block == DELAYSTARTBLOCK) {
184 			iomapp->iomap_bn = IOMAP_DADDR_NULL;
185 			iomapp->iomap_flags |= IOMAP_DELAY;
186 		} else {
187 			iomapp->iomap_bn = XFS_FSB_TO_DB_IO(io, start_block);
188 			if (ISUNWRITTEN(imap))
189 				iomapp->iomap_flags |= IOMAP_UNWRITTEN;
190 		}
191 
192 		if ((iomapp->iomap_offset + iomapp->iomap_bsize) >= nisize) {
193 			iomapp->iomap_flags |= IOMAP_EOF;
194 		}
195 
196 		offset += iomapp->iomap_bsize - iomapp->iomap_delta;
197 	}
198 	return pbm;	/* Return the number filled */
199 }
200 
201 int
202 xfs_iomap(
203 	xfs_iocore_t	*io,
204 	xfs_off_t	offset,
205 	ssize_t		count,
206 	int		flags,
207 	xfs_iomap_t	*iomapp,
208 	int		*niomaps)
209 {
210 	xfs_mount_t	*mp = io->io_mount;
211 	xfs_fileoff_t	offset_fsb, end_fsb;
212 	int		error = 0;
213 	int		lockmode = 0;
214 	xfs_bmbt_irec_t	imap;
215 	int		nimaps = 1;
216 	int		bmapi_flags = 0;
217 	int		iomap_flags = 0;
218 
219 	if (XFS_FORCED_SHUTDOWN(mp))
220 		return XFS_ERROR(EIO);
221 
222 	switch (flags &
223 		(BMAPI_READ | BMAPI_WRITE | BMAPI_ALLOCATE |
224 		 BMAPI_UNWRITTEN | BMAPI_DEVICE)) {
225 	case BMAPI_READ:
226 		xfs_iomap_enter_trace(XFS_IOMAP_READ_ENTER, io, offset, count);
227 		lockmode = XFS_LCK_MAP_SHARED(mp, io);
228 		bmapi_flags = XFS_BMAPI_ENTIRE;
229 		if (flags & BMAPI_IGNSTATE)
230 			bmapi_flags |= XFS_BMAPI_IGSTATE;
231 		break;
232 	case BMAPI_WRITE:
233 		xfs_iomap_enter_trace(XFS_IOMAP_WRITE_ENTER, io, offset, count);
234 		lockmode = XFS_ILOCK_EXCL|XFS_EXTSIZE_WR;
235 		bmapi_flags = 0;
236 		XFS_ILOCK(mp, io, lockmode);
237 		break;
238 	case BMAPI_ALLOCATE:
239 		xfs_iomap_enter_trace(XFS_IOMAP_ALLOC_ENTER, io, offset, count);
240 		lockmode = XFS_ILOCK_SHARED|XFS_EXTSIZE_RD;
241 		bmapi_flags = XFS_BMAPI_ENTIRE;
242 		/* Attempt non-blocking lock */
243 		if (flags & BMAPI_TRYLOCK) {
244 			if (!XFS_ILOCK_NOWAIT(mp, io, lockmode))
245 				return XFS_ERROR(EAGAIN);
246 		} else {
247 			XFS_ILOCK(mp, io, lockmode);
248 		}
249 		break;
250 	case BMAPI_UNWRITTEN:
251 		goto phase2;
252 	case BMAPI_DEVICE:
253 		lockmode = XFS_LCK_MAP_SHARED(mp, io);
254 		iomapp->iomap_target = io->io_flags & XFS_IOCORE_RT ?
255 			mp->m_rtdev_targp : mp->m_ddev_targp;
256 		error = 0;
257 		*niomaps = 1;
258 		goto out;
259 	default:
260 		BUG();
261 	}
262 
263 	ASSERT(offset <= mp->m_maxioffset);
264 	if ((xfs_fsize_t)offset + count > mp->m_maxioffset)
265 		count = mp->m_maxioffset - offset;
266 	end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
267 	offset_fsb = XFS_B_TO_FSBT(mp, offset);
268 
269 	error = XFS_BMAPI(mp, NULL, io, offset_fsb,
270 			(xfs_filblks_t)(end_fsb - offset_fsb),
271 			bmapi_flags,  NULL, 0, &imap,
272 			&nimaps, NULL);
273 
274 	if (error)
275 		goto out;
276 
277 phase2:
278 	switch (flags & (BMAPI_WRITE|BMAPI_ALLOCATE|BMAPI_UNWRITTEN)) {
279 	case BMAPI_WRITE:
280 		/* If we found an extent, return it */
281 		if (nimaps &&
282 		    (imap.br_startblock != HOLESTARTBLOCK) &&
283 		    (imap.br_startblock != DELAYSTARTBLOCK)) {
284 			xfs_iomap_map_trace(XFS_IOMAP_WRITE_MAP, io,
285 					offset, count, iomapp, &imap, flags);
286 			break;
287 		}
288 
289 		if (flags & (BMAPI_DIRECT|BMAPI_MMAP)) {
290 			error = XFS_IOMAP_WRITE_DIRECT(mp, io, offset,
291 					count, flags, &imap, &nimaps, nimaps);
292 		} else {
293 			error = XFS_IOMAP_WRITE_DELAY(mp, io, offset, count,
294 					flags, &imap, &nimaps);
295 		}
296 		if (!error) {
297 			xfs_iomap_map_trace(XFS_IOMAP_ALLOC_MAP, io,
298 					offset, count, iomapp, &imap, flags);
299 		}
300 		iomap_flags = IOMAP_NEW;
301 		break;
302 	case BMAPI_ALLOCATE:
303 		/* If we found an extent, return it */
304 		XFS_IUNLOCK(mp, io, lockmode);
305 		lockmode = 0;
306 
307 		if (nimaps && !ISNULLSTARTBLOCK(imap.br_startblock)) {
308 			xfs_iomap_map_trace(XFS_IOMAP_WRITE_MAP, io,
309 					offset, count, iomapp, &imap, flags);
310 			break;
311 		}
312 
313 		error = XFS_IOMAP_WRITE_ALLOCATE(mp, io, offset, count,
314 						 &imap, &nimaps);
315 		break;
316 	case BMAPI_UNWRITTEN:
317 		lockmode = 0;
318 		error = XFS_IOMAP_WRITE_UNWRITTEN(mp, io, offset, count);
319 		nimaps = 0;
320 		break;
321 	}
322 
323 	if (nimaps) {
324 		*niomaps = xfs_imap_to_bmap(io, offset, &imap,
325 					    iomapp, nimaps, *niomaps, iomap_flags);
326 	} else if (niomaps) {
327 		*niomaps = 0;
328 	}
329 
330 out:
331 	if (lockmode)
332 		XFS_IUNLOCK(mp, io, lockmode);
333 	return XFS_ERROR(error);
334 }
335 
336 STATIC int
337 xfs_flush_space(
338 	xfs_inode_t	*ip,
339 	int		*fsynced,
340 	int		*ioflags)
341 {
342 	switch (*fsynced) {
343 	case 0:
344 		if (ip->i_delayed_blks) {
345 			xfs_iunlock(ip, XFS_ILOCK_EXCL);
346 			xfs_flush_inode(ip);
347 			xfs_ilock(ip, XFS_ILOCK_EXCL);
348 			*fsynced = 1;
349 		} else {
350 			*ioflags |= BMAPI_SYNC;
351 			*fsynced = 2;
352 		}
353 		return 0;
354 	case 1:
355 		*fsynced = 2;
356 		*ioflags |= BMAPI_SYNC;
357 		return 0;
358 	case 2:
359 		xfs_iunlock(ip, XFS_ILOCK_EXCL);
360 		xfs_flush_device(ip);
361 		xfs_ilock(ip, XFS_ILOCK_EXCL);
362 		*fsynced = 3;
363 		return 0;
364 	}
365 	return 1;
366 }
367 
368 int
369 xfs_iomap_write_direct(
370 	xfs_inode_t	*ip,
371 	xfs_off_t	offset,
372 	size_t		count,
373 	int		flags,
374 	xfs_bmbt_irec_t *ret_imap,
375 	int		*nmaps,
376 	int		found)
377 {
378 	xfs_mount_t	*mp = ip->i_mount;
379 	xfs_iocore_t	*io = &ip->i_iocore;
380 	xfs_fileoff_t	offset_fsb;
381 	xfs_fileoff_t	last_fsb;
382 	xfs_filblks_t	count_fsb;
383 	xfs_fsize_t	isize;
384 	xfs_fsblock_t	firstfsb;
385 	int		nimaps, maps;
386 	int		error;
387 	int		bmapi_flag;
388 	int		quota_flag;
389 	int		rt;
390 	xfs_trans_t	*tp;
391 	xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS], *imapp;
392 	xfs_bmap_free_t free_list;
393 	int		aeof;
394 	xfs_filblks_t	datablocks, qblocks, resblks;
395 	int		committed;
396 	int		numrtextents;
397 
398 	/*
399 	 * Make sure that the dquots are there. This doesn't hold
400 	 * the ilock across a disk read.
401 	 */
402 	error = XFS_QM_DQATTACH(ip->i_mount, ip, XFS_QMOPT_ILOCKED);
403 	if (error)
404 		return XFS_ERROR(error);
405 
406 	maps = min(XFS_WRITE_IMAPS, *nmaps);
407 	nimaps = maps;
408 
409 	isize = ip->i_d.di_size;
410 	aeof = (offset + count) > isize;
411 
412 	if (io->io_new_size > isize)
413 		isize = io->io_new_size;
414 
415 	offset_fsb = XFS_B_TO_FSBT(mp, offset);
416 	last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
417 	count_fsb = last_fsb - offset_fsb;
418 	if (found && (ret_imap->br_startblock == HOLESTARTBLOCK)) {
419 		xfs_fileoff_t	map_last_fsb;
420 
421 		map_last_fsb = ret_imap->br_blockcount + ret_imap->br_startoff;
422 		if (map_last_fsb < last_fsb) {
423 			last_fsb = map_last_fsb;
424 			count_fsb = last_fsb - offset_fsb;
425 		}
426 		ASSERT(count_fsb > 0);
427 	}
428 
429 	/*
430 	 * Determine if reserving space on the data or realtime partition.
431 	 */
432 	if ((rt = XFS_IS_REALTIME_INODE(ip))) {
433 		xfs_extlen_t	extsz;
434 
435 		if (!(extsz = ip->i_d.di_extsize))
436 			extsz = mp->m_sb.sb_rextsize;
437 		numrtextents = qblocks = (count_fsb + extsz - 1);
438 		do_div(numrtextents, mp->m_sb.sb_rextsize);
439 		quota_flag = XFS_QMOPT_RES_RTBLKS;
440 		datablocks = 0;
441 	} else {
442 		datablocks = qblocks = count_fsb;
443 		quota_flag = XFS_QMOPT_RES_REGBLKS;
444 		numrtextents = 0;
445 	}
446 
447 	/*
448 	 * Allocate and setup the transaction
449 	 */
450 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
451 	tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
452 	resblks = XFS_DIOSTRAT_SPACE_RES(mp, datablocks);
453 	error = xfs_trans_reserve(tp, resblks,
454 			XFS_WRITE_LOG_RES(mp), numrtextents,
455 			XFS_TRANS_PERM_LOG_RES,
456 			XFS_WRITE_LOG_COUNT);
457 
458 	/*
459 	 * Check for running out of space, note: need lock to return
460 	 */
461 	if (error)
462 		xfs_trans_cancel(tp, 0);
463 	xfs_ilock(ip, XFS_ILOCK_EXCL);
464 	if (error)
465 		goto error_out;
466 
467 	if (XFS_TRANS_RESERVE_QUOTA_NBLKS(mp, tp, ip, qblocks, 0, quota_flag)) {
468 		error = (EDQUOT);
469 		goto error1;
470 	}
471 
472 	bmapi_flag = XFS_BMAPI_WRITE;
473 	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
474 	xfs_trans_ihold(tp, ip);
475 
476 	if (!(flags & BMAPI_MMAP) && (offset < ip->i_d.di_size || rt))
477 		bmapi_flag |= XFS_BMAPI_PREALLOC;
478 
479 	/*
480 	 * Issue the bmapi() call to allocate the blocks
481 	 */
482 	XFS_BMAP_INIT(&free_list, &firstfsb);
483 	nimaps = 1;
484 	imapp = &imap[0];
485 	error = xfs_bmapi(tp, ip, offset_fsb, count_fsb,
486 		bmapi_flag, &firstfsb, 0, imapp, &nimaps, &free_list);
487 	if (error)
488 		goto error0;
489 
490 	/*
491 	 * Complete the transaction
492 	 */
493 	error = xfs_bmap_finish(&tp, &free_list, firstfsb, &committed);
494 	if (error)
495 		goto error0;
496 	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES, NULL);
497 	if (error)
498 		goto error_out;
499 
500 	/*
501 	 * Copy any maps to caller's array and return any error.
502 	 */
503 	if (nimaps == 0) {
504 		error = (ENOSPC);
505 		goto error_out;
506 	}
507 
508 	*ret_imap = imap[0];
509 	*nmaps = 1;
510 	if ( !(io->io_flags & XFS_IOCORE_RT)  && !ret_imap->br_startblock) {
511                 cmn_err(CE_PANIC,"Access to block zero:  fs <%s> inode: %lld "
512                         "start_block : %llx start_off : %llx blkcnt : %llx "
513                         "extent-state : %x \n",
514                         (ip->i_mount)->m_fsname,
515                         (long long)ip->i_ino,
516                         ret_imap->br_startblock, ret_imap->br_startoff,
517                         ret_imap->br_blockcount,ret_imap->br_state);
518         }
519 	return 0;
520 
521 error0:	/* Cancel bmap, unlock inode, unreserve quota blocks, cancel trans */
522 	xfs_bmap_cancel(&free_list);
523 	XFS_TRANS_UNRESERVE_QUOTA_NBLKS(mp, tp, ip, qblocks, 0, quota_flag);
524 
525 error1:	/* Just cancel transaction */
526 	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
527 	*nmaps = 0;	/* nothing set-up here */
528 
529 error_out:
530 	return XFS_ERROR(error);
531 }
532 
533 int
534 xfs_iomap_write_delay(
535 	xfs_inode_t	*ip,
536 	xfs_off_t	offset,
537 	size_t		count,
538 	int		ioflag,
539 	xfs_bmbt_irec_t *ret_imap,
540 	int		*nmaps)
541 {
542 	xfs_mount_t	*mp = ip->i_mount;
543 	xfs_iocore_t	*io = &ip->i_iocore;
544 	xfs_fileoff_t	offset_fsb;
545 	xfs_fileoff_t	last_fsb;
546 	xfs_fsize_t	isize;
547 	xfs_fsblock_t	firstblock;
548 	int		nimaps;
549 	int		error;
550 	xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS];
551 	int		aeof;
552 	int		fsynced = 0;
553 
554 	ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE) != 0);
555 
556 	/*
557 	 * Make sure that the dquots are there. This doesn't hold
558 	 * the ilock across a disk read.
559 	 */
560 
561 	error = XFS_QM_DQATTACH(mp, ip, XFS_QMOPT_ILOCKED);
562 	if (error)
563 		return XFS_ERROR(error);
564 
565 retry:
566 	isize = ip->i_d.di_size;
567 	if (io->io_new_size > isize) {
568 		isize = io->io_new_size;
569 	}
570 
571 	aeof = 0;
572 	offset_fsb = XFS_B_TO_FSBT(mp, offset);
573 	last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
574 	/*
575 	 * If the caller is doing a write at the end of the file,
576 	 * then extend the allocation (and the buffer used for the write)
577 	 * out to the file system's write iosize.  We clean up any extra
578 	 * space left over when the file is closed in xfs_inactive().
579 	 *
580 	 * For sync writes, we are flushing delayed allocate space to
581 	 * try to make additional space available for allocation near
582 	 * the filesystem full boundary - preallocation hurts in that
583 	 * situation, of course.
584 	 */
585 	if (!(ioflag & BMAPI_SYNC) && ((offset + count) > ip->i_d.di_size)) {
586 		xfs_off_t	aligned_offset;
587 		xfs_filblks_t   count_fsb;
588 		unsigned int	iosize;
589 		xfs_fileoff_t	ioalign;
590 		int		n;
591 		xfs_fileoff_t   start_fsb;
592 
593 		/*
594 		 * If there are any real blocks past eof, then don't
595 		 * do any speculative allocation.
596 		 */
597 		start_fsb = XFS_B_TO_FSBT(mp,
598 					((xfs_ufsize_t)(offset + count - 1)));
599 		count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
600 		while (count_fsb > 0) {
601 			nimaps = XFS_WRITE_IMAPS;
602 			error = XFS_BMAPI(mp, NULL, io, start_fsb, count_fsb,
603 					0, &firstblock, 0, imap, &nimaps, NULL);
604 			if (error) {
605 				return error;
606 			}
607 			for (n = 0; n < nimaps; n++) {
608 				if ( !(io->io_flags & XFS_IOCORE_RT)  &&
609 					!imap[n].br_startblock) {
610 					cmn_err(CE_PANIC,"Access to block "
611 						"zero:  fs <%s> inode: %lld "
612 						"start_block : %llx start_off "
613 						": %llx blkcnt : %llx "
614 						"extent-state : %x \n",
615 						(ip->i_mount)->m_fsname,
616 						(long long)ip->i_ino,
617 						imap[n].br_startblock,
618 						imap[n].br_startoff,
619 						imap[n].br_blockcount,
620 						imap[n].br_state);
621         			}
622 				if ((imap[n].br_startblock != HOLESTARTBLOCK) &&
623 				    (imap[n].br_startblock != DELAYSTARTBLOCK)) {
624 					goto write_map;
625 				}
626 				start_fsb += imap[n].br_blockcount;
627 				count_fsb -= imap[n].br_blockcount;
628 			}
629 		}
630 		iosize = mp->m_writeio_blocks;
631 		aligned_offset = XFS_WRITEIO_ALIGN(mp, (offset + count - 1));
632 		ioalign = XFS_B_TO_FSBT(mp, aligned_offset);
633 		last_fsb = ioalign + iosize;
634 		aeof = 1;
635 	}
636 write_map:
637 	nimaps = XFS_WRITE_IMAPS;
638 	firstblock = NULLFSBLOCK;
639 
640 	/*
641 	 * If mounted with the "-o swalloc" option, roundup the allocation
642 	 * request to a stripe width boundary if the file size is >=
643 	 * stripe width and we are allocating past the allocation eof.
644 	 */
645 	if (!(io->io_flags & XFS_IOCORE_RT) && mp->m_swidth
646 	    && (mp->m_flags & XFS_MOUNT_SWALLOC)
647 	    && (isize >= XFS_FSB_TO_B(mp, mp->m_swidth)) && aeof) {
648 		int eof;
649 		xfs_fileoff_t new_last_fsb;
650 
651 		new_last_fsb = roundup_64(last_fsb, mp->m_swidth);
652 		error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
653 		if (error) {
654 			return error;
655 		}
656 		if (eof) {
657 			last_fsb = new_last_fsb;
658 		}
659 	/*
660 	 * Roundup the allocation request to a stripe unit (m_dalign) boundary
661 	 * if the file size is >= stripe unit size, and we are allocating past
662 	 * the allocation eof.
663 	 */
664 	} else if (!(io->io_flags & XFS_IOCORE_RT) && mp->m_dalign &&
665 		   (isize >= XFS_FSB_TO_B(mp, mp->m_dalign)) && aeof) {
666 		int eof;
667 		xfs_fileoff_t new_last_fsb;
668 		new_last_fsb = roundup_64(last_fsb, mp->m_dalign);
669 		error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
670 		if (error) {
671 			return error;
672 		}
673 		if (eof) {
674 			last_fsb = new_last_fsb;
675 		}
676 	/*
677 	 * Round up the allocation request to a real-time extent boundary
678 	 * if the file is on the real-time subvolume.
679 	 */
680 	} else if (io->io_flags & XFS_IOCORE_RT && aeof) {
681 		int eof;
682 		xfs_fileoff_t new_last_fsb;
683 
684 		new_last_fsb = roundup_64(last_fsb, mp->m_sb.sb_rextsize);
685 		error = XFS_BMAP_EOF(mp, io, new_last_fsb, XFS_DATA_FORK, &eof);
686 		if (error) {
687 			return error;
688 		}
689 		if (eof)
690 			last_fsb = new_last_fsb;
691 	}
692 	error = xfs_bmapi(NULL, ip, offset_fsb,
693 			  (xfs_filblks_t)(last_fsb - offset_fsb),
694 			  XFS_BMAPI_DELAY | XFS_BMAPI_WRITE |
695 			  XFS_BMAPI_ENTIRE, &firstblock, 1, imap,
696 			  &nimaps, NULL);
697 	/*
698 	 * This can be EDQUOT, if nimaps == 0
699 	 */
700 	if (error && (error != ENOSPC)) {
701 		return XFS_ERROR(error);
702 	}
703 	/*
704 	 * If bmapi returned us nothing, and if we didn't get back EDQUOT,
705 	 * then we must have run out of space.
706 	 */
707 	if (nimaps == 0) {
708 		xfs_iomap_enter_trace(XFS_IOMAP_WRITE_NOSPACE,
709 					io, offset, count);
710 		if (xfs_flush_space(ip, &fsynced, &ioflag))
711 			return XFS_ERROR(ENOSPC);
712 
713 		error = 0;
714 		goto retry;
715 	}
716 
717 	*ret_imap = imap[0];
718 	*nmaps = 1;
719 	if ( !(io->io_flags & XFS_IOCORE_RT)  && !ret_imap->br_startblock) {
720 		cmn_err(CE_PANIC,"Access to block zero:  fs <%s> inode: %lld "
721                         "start_block : %llx start_off : %llx blkcnt : %llx "
722                         "extent-state : %x \n",
723                         (ip->i_mount)->m_fsname,
724                         (long long)ip->i_ino,
725                         ret_imap->br_startblock, ret_imap->br_startoff,
726                         ret_imap->br_blockcount,ret_imap->br_state);
727 	}
728 	return 0;
729 }
730 
731 /*
732  * Pass in a delayed allocate extent, convert it to real extents;
733  * return to the caller the extent we create which maps on top of
734  * the originating callers request.
735  *
736  * Called without a lock on the inode.
737  */
738 int
739 xfs_iomap_write_allocate(
740 	xfs_inode_t	*ip,
741 	xfs_off_t	offset,
742 	size_t		count,
743 	xfs_bmbt_irec_t *map,
744 	int		*retmap)
745 {
746 	xfs_mount_t	*mp = ip->i_mount;
747 	xfs_iocore_t    *io = &ip->i_iocore;
748 	xfs_fileoff_t	offset_fsb, last_block;
749 	xfs_fileoff_t	end_fsb, map_start_fsb;
750 	xfs_fsblock_t	first_block;
751 	xfs_bmap_free_t	free_list;
752 	xfs_filblks_t	count_fsb;
753 	xfs_bmbt_irec_t	imap[XFS_STRAT_WRITE_IMAPS];
754 	xfs_trans_t	*tp;
755 	int		i, nimaps, committed;
756 	int		error = 0;
757 	int		nres;
758 
759 	*retmap = 0;
760 
761 	/*
762 	 * Make sure that the dquots are there.
763 	 */
764 	if ((error = XFS_QM_DQATTACH(mp, ip, 0)))
765 		return XFS_ERROR(error);
766 
767 	offset_fsb = XFS_B_TO_FSBT(mp, offset);
768 	count_fsb = map->br_blockcount;
769 	map_start_fsb = map->br_startoff;
770 
771 	XFS_STATS_ADD(xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
772 
773 	while (count_fsb != 0) {
774 		/*
775 		 * Set up a transaction with which to allocate the
776 		 * backing store for the file.  Do allocations in a
777 		 * loop until we get some space in the range we are
778 		 * interested in.  The other space that might be allocated
779 		 * is in the delayed allocation extent on which we sit
780 		 * but before our buffer starts.
781 		 */
782 
783 		nimaps = 0;
784 		while (nimaps == 0) {
785 			tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
786 			nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
787 			error = xfs_trans_reserve(tp, nres,
788 					XFS_WRITE_LOG_RES(mp),
789 					0, XFS_TRANS_PERM_LOG_RES,
790 					XFS_WRITE_LOG_COUNT);
791 			if (error == ENOSPC) {
792 				error = xfs_trans_reserve(tp, 0,
793 						XFS_WRITE_LOG_RES(mp),
794 						0,
795 						XFS_TRANS_PERM_LOG_RES,
796 						XFS_WRITE_LOG_COUNT);
797 			}
798 			if (error) {
799 				xfs_trans_cancel(tp, 0);
800 				return XFS_ERROR(error);
801 			}
802 			xfs_ilock(ip, XFS_ILOCK_EXCL);
803 			xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
804 			xfs_trans_ihold(tp, ip);
805 
806 			XFS_BMAP_INIT(&free_list, &first_block);
807 
808 			nimaps = XFS_STRAT_WRITE_IMAPS;
809 			/*
810 			 * Ensure we don't go beyond eof - it is possible
811 			 * the extents changed since we did the read call,
812 			 * we dropped the ilock in the interim.
813 			 */
814 
815 			end_fsb = XFS_B_TO_FSB(mp, ip->i_d.di_size);
816 			xfs_bmap_last_offset(NULL, ip, &last_block,
817 				XFS_DATA_FORK);
818 			last_block = XFS_FILEOFF_MAX(last_block, end_fsb);
819 			if ((map_start_fsb + count_fsb) > last_block) {
820 				count_fsb = last_block - map_start_fsb;
821 				if (count_fsb == 0) {
822 					error = EAGAIN;
823 					goto trans_cancel;
824 				}
825 			}
826 
827 			/* Go get the actual blocks */
828 			error = xfs_bmapi(tp, ip, map_start_fsb, count_fsb,
829 					XFS_BMAPI_WRITE, &first_block, 1,
830 					imap, &nimaps, &free_list);
831 			if (error)
832 				goto trans_cancel;
833 
834 			error = xfs_bmap_finish(&tp, &free_list,
835 					first_block, &committed);
836 			if (error)
837 				goto trans_cancel;
838 
839 			error = xfs_trans_commit(tp,
840 					XFS_TRANS_RELEASE_LOG_RES, NULL);
841 			if (error)
842 				goto error0;
843 
844 			xfs_iunlock(ip, XFS_ILOCK_EXCL);
845 		}
846 
847 		/*
848 		 * See if we were able to allocate an extent that
849 		 * covers at least part of the callers request
850 		 */
851 
852 		for (i = 0; i < nimaps; i++) {
853 			if ( !(io->io_flags & XFS_IOCORE_RT)  &&
854 				!imap[i].br_startblock) {
855 				cmn_err(CE_PANIC,"Access to block zero:  "
856 					"fs <%s> inode: %lld "
857 					"start_block : %llx start_off : %llx "
858 					"blkcnt : %llx extent-state : %x \n",
859 					(ip->i_mount)->m_fsname,
860 					(long long)ip->i_ino,
861 					imap[i].br_startblock,
862 					imap[i].br_startoff,
863 				        imap[i].br_blockcount,imap[i].br_state);
864                         }
865 			if ((offset_fsb >= imap[i].br_startoff) &&
866 			    (offset_fsb < (imap[i].br_startoff +
867 					   imap[i].br_blockcount))) {
868 				*map = imap[i];
869 				*retmap = 1;
870 				XFS_STATS_INC(xs_xstrat_quick);
871 				return 0;
872 			}
873 			count_fsb -= imap[i].br_blockcount;
874 		}
875 
876 		/* So far we have not mapped the requested part of the
877 		 * file, just surrounding data, try again.
878 		 */
879 		nimaps--;
880 		map_start_fsb = imap[nimaps].br_startoff +
881 				imap[nimaps].br_blockcount;
882 	}
883 
884 trans_cancel:
885 	xfs_bmap_cancel(&free_list);
886 	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
887 error0:
888 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
889 	return XFS_ERROR(error);
890 }
891 
892 int
893 xfs_iomap_write_unwritten(
894 	xfs_inode_t	*ip,
895 	xfs_off_t	offset,
896 	size_t		count)
897 {
898 	xfs_mount_t	*mp = ip->i_mount;
899 	xfs_iocore_t    *io = &ip->i_iocore;
900 	xfs_trans_t	*tp;
901 	xfs_fileoff_t	offset_fsb;
902 	xfs_filblks_t	count_fsb;
903 	xfs_filblks_t	numblks_fsb;
904 	xfs_bmbt_irec_t	imap;
905 	int		committed;
906 	int		error;
907 	int		nres;
908 	int		nimaps;
909 	xfs_fsblock_t	firstfsb;
910 	xfs_bmap_free_t	free_list;
911 
912 	xfs_iomap_enter_trace(XFS_IOMAP_UNWRITTEN,
913 				&ip->i_iocore, offset, count);
914 
915 	offset_fsb = XFS_B_TO_FSBT(mp, offset);
916 	count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
917 	count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
918 
919 	do {
920 		nres = XFS_DIOSTRAT_SPACE_RES(mp, 0);
921 
922 		/*
923 		 * set up a transaction to convert the range of extents
924 		 * from unwritten to real. Do allocations in a loop until
925 		 * we have covered the range passed in.
926 		 */
927 
928 		tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
929 		error = xfs_trans_reserve(tp, nres,
930 				XFS_WRITE_LOG_RES(mp), 0,
931 				XFS_TRANS_PERM_LOG_RES,
932 				XFS_WRITE_LOG_COUNT);
933 		if (error) {
934 			xfs_trans_cancel(tp, 0);
935 			goto error0;
936 		}
937 
938 		xfs_ilock(ip, XFS_ILOCK_EXCL);
939 		xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
940 		xfs_trans_ihold(tp, ip);
941 
942 		/*
943 		 * Modify the unwritten extent state of the buffer.
944 		 */
945 		XFS_BMAP_INIT(&free_list, &firstfsb);
946 		nimaps = 1;
947 		error = xfs_bmapi(tp, ip, offset_fsb, count_fsb,
948 				  XFS_BMAPI_WRITE, &firstfsb,
949 				  1, &imap, &nimaps, &free_list);
950 		if (error)
951 			goto error_on_bmapi_transaction;
952 
953 		error = xfs_bmap_finish(&(tp), &(free_list),
954 				firstfsb, &committed);
955 		if (error)
956 			goto error_on_bmapi_transaction;
957 
958 		error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES, NULL);
959 		xfs_iunlock(ip, XFS_ILOCK_EXCL);
960 		if (error)
961 			goto error0;
962 
963 		if ( !(io->io_flags & XFS_IOCORE_RT)  && !imap.br_startblock) {
964 			cmn_err(CE_PANIC,"Access to block zero:  fs <%s> "
965 				"inode: %lld start_block : %llx start_off : "
966 				"%llx blkcnt : %llx extent-state : %x \n",
967 				(ip->i_mount)->m_fsname,
968 				(long long)ip->i_ino,
969 				imap.br_startblock,imap.br_startoff,
970 				imap.br_blockcount,imap.br_state);
971         	}
972 
973 		if ((numblks_fsb = imap.br_blockcount) == 0) {
974 			/*
975 			 * The numblks_fsb value should always get
976 			 * smaller, otherwise the loop is stuck.
977 			 */
978 			ASSERT(imap.br_blockcount);
979 			break;
980 		}
981 		offset_fsb += numblks_fsb;
982 		count_fsb -= numblks_fsb;
983 	} while (count_fsb > 0);
984 
985 	return 0;
986 
987 error_on_bmapi_transaction:
988 	xfs_bmap_cancel(&free_list);
989 	xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT));
990 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
991 error0:
992 	return XFS_ERROR(error);
993 }
994