• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * Copyright (c) 2000-2005 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_types.h"
21 #include "xfs_bit.h"
22 #include "xfs_log.h"
23 #include "xfs_inum.h"
24 #include "xfs_trans.h"
25 #include "xfs_sb.h"
26 #include "xfs_ag.h"
27 #include "xfs_dir2.h"
28 #include "xfs_dmapi.h"
29 #include "xfs_mount.h"
30 #include "xfs_bmap_btree.h"
31 #include "xfs_alloc_btree.h"
32 #include "xfs_ialloc_btree.h"
33 #include "xfs_dir2_sf.h"
34 #include "xfs_attr_sf.h"
35 #include "xfs_dinode.h"
36 #include "xfs_inode.h"
37 #include "xfs_btree.h"
38 #include "xfs_ialloc.h"
39 #include "xfs_alloc.h"
40 #include "xfs_bmap.h"
41 #include "xfs_rtalloc.h"
42 #include "xfs_fsops.h"
43 #include "xfs_error.h"
44 #include "xfs_rw.h"
45 #include "xfs_inode_item.h"
46 #include "xfs_trans_space.h"
47 #include "xfs_utils.h"
48 
49 
50 /*
51  * Prototypes for internal functions.
52  */
53 
54 
55 STATIC int xfs_rtallocate_range(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
56 		xfs_extlen_t, xfs_buf_t **, xfs_fsblock_t *);
57 STATIC int xfs_rtany_summary(xfs_mount_t *, xfs_trans_t *, int, int,
58 		xfs_rtblock_t, xfs_buf_t **, xfs_fsblock_t *, int *);
59 STATIC int xfs_rtcheck_range(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
60 		xfs_extlen_t, int, xfs_rtblock_t *, int *);
61 STATIC int xfs_rtfind_back(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
62 		xfs_rtblock_t, xfs_rtblock_t *);
63 STATIC int xfs_rtfind_forw(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
64 		xfs_rtblock_t, xfs_rtblock_t *);
65 STATIC int xfs_rtget_summary( xfs_mount_t *, xfs_trans_t *, int,
66 		xfs_rtblock_t, xfs_buf_t **, xfs_fsblock_t *, xfs_suminfo_t *);
67 STATIC int xfs_rtmodify_range(xfs_mount_t *, xfs_trans_t *, xfs_rtblock_t,
68 		xfs_extlen_t, int);
69 STATIC int xfs_rtmodify_summary(xfs_mount_t *, xfs_trans_t *, int,
70 		xfs_rtblock_t, int, xfs_buf_t **, xfs_fsblock_t *);
71 
72 /*
73  * Internal functions.
74  */
75 
76 /*
77  * Allocate space to the bitmap or summary file, and zero it, for growfs.
78  */
79 STATIC int				/* error */
xfs_growfs_rt_alloc(xfs_mount_t * mp,xfs_extlen_t oblocks,xfs_extlen_t nblocks,xfs_ino_t ino)80 xfs_growfs_rt_alloc(
81 	xfs_mount_t	*mp,		/* file system mount point */
82 	xfs_extlen_t	oblocks,	/* old count of blocks */
83 	xfs_extlen_t	nblocks,	/* new count of blocks */
84 	xfs_ino_t	ino)		/* inode number (bitmap/summary) */
85 {
86 	xfs_fileoff_t	bno;		/* block number in file */
87 	xfs_buf_t	*bp;		/* temporary buffer for zeroing */
88 	int		committed;	/* transaction committed flag */
89 	xfs_daddr_t	d;		/* disk block address */
90 	int		error;		/* error return value */
91 	xfs_fsblock_t	firstblock;	/* first block allocated in xaction */
92 	xfs_bmap_free_t	flist;		/* list of freed blocks */
93 	xfs_fsblock_t	fsbno;		/* filesystem block for bno */
94 	xfs_inode_t	*ip;		/* pointer to incore inode */
95 	xfs_bmbt_irec_t	map;		/* block map output */
96 	int		nmap;		/* number of block maps */
97 	int		resblks;	/* space reservation */
98 
99 	/*
100 	 * Allocate space to the file, as necessary.
101 	 */
102 	while (oblocks < nblocks) {
103 		int		cancelflags = 0;
104 		xfs_trans_t	*tp;
105 
106 		tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_ALLOC);
107 		resblks = XFS_GROWFSRT_SPACE_RES(mp, nblocks - oblocks);
108 		/*
109 		 * Reserve space & log for one extent added to the file.
110 		 */
111 		if ((error = xfs_trans_reserve(tp, resblks,
112 				XFS_GROWRTALLOC_LOG_RES(mp), 0,
113 				XFS_TRANS_PERM_LOG_RES,
114 				XFS_DEFAULT_PERM_LOG_COUNT)))
115 			goto error_cancel;
116 		cancelflags = XFS_TRANS_RELEASE_LOG_RES;
117 		/*
118 		 * Lock the inode.
119 		 */
120 		if ((error = xfs_trans_iget(mp, tp, ino, 0,
121 						XFS_ILOCK_EXCL, &ip)))
122 			goto error_cancel;
123 		xfs_bmap_init(&flist, &firstblock);
124 		/*
125 		 * Allocate blocks to the bitmap file.
126 		 */
127 		nmap = 1;
128 		cancelflags |= XFS_TRANS_ABORT;
129 		error = xfs_bmapi(tp, ip, oblocks, nblocks - oblocks,
130 			XFS_BMAPI_WRITE | XFS_BMAPI_METADATA, &firstblock,
131 			resblks, &map, &nmap, &flist, NULL);
132 		if (!error && nmap < 1)
133 			error = XFS_ERROR(ENOSPC);
134 		if (error)
135 			goto error_cancel;
136 		/*
137 		 * Free any blocks freed up in the transaction, then commit.
138 		 */
139 		error = xfs_bmap_finish(&tp, &flist, &committed);
140 		if (error)
141 			goto error_cancel;
142 		error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
143 		if (error)
144 			goto error;
145 		/*
146 		 * Now we need to clear the allocated blocks.
147 		 * Do this one block per transaction, to keep it simple.
148 		 */
149 		cancelflags = 0;
150 		for (bno = map.br_startoff, fsbno = map.br_startblock;
151 		     bno < map.br_startoff + map.br_blockcount;
152 		     bno++, fsbno++) {
153 			tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_ZERO);
154 			/*
155 			 * Reserve log for one block zeroing.
156 			 */
157 			if ((error = xfs_trans_reserve(tp, 0,
158 					XFS_GROWRTZERO_LOG_RES(mp), 0, 0, 0)))
159 				goto error_cancel;
160 			/*
161 			 * Lock the bitmap inode.
162 			 */
163 			if ((error = xfs_trans_iget(mp, tp, ino, 0,
164 							XFS_ILOCK_EXCL, &ip)))
165 				goto error_cancel;
166 			/*
167 			 * Get a buffer for the block.
168 			 */
169 			d = XFS_FSB_TO_DADDR(mp, fsbno);
170 			bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
171 				mp->m_bsize, 0);
172 			if (bp == NULL) {
173 				error = XFS_ERROR(EIO);
174 error_cancel:
175 				xfs_trans_cancel(tp, cancelflags);
176 				goto error;
177 			}
178 			memset(XFS_BUF_PTR(bp), 0, mp->m_sb.sb_blocksize);
179 			xfs_trans_log_buf(tp, bp, 0, mp->m_sb.sb_blocksize - 1);
180 			/*
181 			 * Commit the transaction.
182 			 */
183 			error = xfs_trans_commit(tp, 0);
184 			if (error)
185 				goto error;
186 		}
187 		/*
188 		 * Go on to the next extent, if any.
189 		 */
190 		oblocks = map.br_startoff + map.br_blockcount;
191 	}
192 	return 0;
193 error:
194 	return error;
195 }
196 
197 /*
198  * Attempt to allocate an extent minlen<=len<=maxlen starting from
199  * bitmap block bbno.  If we don't get maxlen then use prod to trim
200  * the length, if given.  Returns error; returns starting block in *rtblock.
201  * The lengths are all in rtextents.
202  */
203 STATIC int				/* error */
xfs_rtallocate_extent_block(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t bbno,xfs_extlen_t minlen,xfs_extlen_t maxlen,xfs_extlen_t * len,xfs_rtblock_t * nextp,xfs_buf_t ** rbpp,xfs_fsblock_t * rsb,xfs_extlen_t prod,xfs_rtblock_t * rtblock)204 xfs_rtallocate_extent_block(
205 	xfs_mount_t	*mp,		/* file system mount point */
206 	xfs_trans_t	*tp,		/* transaction pointer */
207 	xfs_rtblock_t	bbno,		/* bitmap block number */
208 	xfs_extlen_t	minlen,		/* minimum length to allocate */
209 	xfs_extlen_t	maxlen,		/* maximum length to allocate */
210 	xfs_extlen_t	*len,		/* out: actual length allocated */
211 	xfs_rtblock_t	*nextp,		/* out: next block to try */
212 	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
213 	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
214 	xfs_extlen_t	prod,		/* extent product factor */
215 	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
216 {
217 	xfs_rtblock_t	besti;		/* best rtblock found so far */
218 	xfs_rtblock_t	bestlen;	/* best length found so far */
219 	xfs_rtblock_t	end;		/* last rtblock in chunk */
220 	int		error;		/* error value */
221 	xfs_rtblock_t	i;		/* current rtblock trying */
222 	xfs_rtblock_t	next;		/* next rtblock to try */
223 	int		stat;		/* status from internal calls */
224 
225 	/*
226 	 * Loop over all the extents starting in this bitmap block,
227 	 * looking for one that's long enough.
228 	 */
229 	for (i = XFS_BLOCKTOBIT(mp, bbno), besti = -1, bestlen = 0,
230 		end = XFS_BLOCKTOBIT(mp, bbno + 1) - 1;
231 	     i <= end;
232 	     i++) {
233 		/*
234 		 * See if there's a free extent of maxlen starting at i.
235 		 * If it's not so then next will contain the first non-free.
236 		 */
237 		error = xfs_rtcheck_range(mp, tp, i, maxlen, 1, &next, &stat);
238 		if (error) {
239 			return error;
240 		}
241 		if (stat) {
242 			/*
243 			 * i for maxlen is all free, allocate and return that.
244 			 */
245 			error = xfs_rtallocate_range(mp, tp, i, maxlen, rbpp,
246 				rsb);
247 			if (error) {
248 				return error;
249 			}
250 			*len = maxlen;
251 			*rtblock = i;
252 			return 0;
253 		}
254 		/*
255 		 * In the case where we have a variable-sized allocation
256 		 * request, figure out how big this free piece is,
257 		 * and if it's big enough for the minimum, and the best
258 		 * so far, remember it.
259 		 */
260 		if (minlen < maxlen) {
261 			xfs_rtblock_t	thislen;	/* this extent size */
262 
263 			thislen = next - i;
264 			if (thislen >= minlen && thislen > bestlen) {
265 				besti = i;
266 				bestlen = thislen;
267 			}
268 		}
269 		/*
270 		 * If not done yet, find the start of the next free space.
271 		 */
272 		if (next < end) {
273 			error = xfs_rtfind_forw(mp, tp, next, end, &i);
274 			if (error) {
275 				return error;
276 			}
277 		} else
278 			break;
279 	}
280 	/*
281 	 * Searched the whole thing & didn't find a maxlen free extent.
282 	 */
283 	if (minlen < maxlen && besti != -1) {
284 		xfs_extlen_t	p;	/* amount to trim length by */
285 
286 		/*
287 		 * If size should be a multiple of prod, make that so.
288 		 */
289 		if (prod > 1 && (p = do_mod(bestlen, prod)))
290 			bestlen -= p;
291 		/*
292 		 * Allocate besti for bestlen & return that.
293 		 */
294 		error = xfs_rtallocate_range(mp, tp, besti, bestlen, rbpp, rsb);
295 		if (error) {
296 			return error;
297 		}
298 		*len = bestlen;
299 		*rtblock = besti;
300 		return 0;
301 	}
302 	/*
303 	 * Allocation failed.  Set *nextp to the next block to try.
304 	 */
305 	*nextp = next;
306 	*rtblock = NULLRTBLOCK;
307 	return 0;
308 }
309 
310 /*
311  * Allocate an extent of length minlen<=len<=maxlen, starting at block
312  * bno.  If we don't get maxlen then use prod to trim the length, if given.
313  * Returns error; returns starting block in *rtblock.
314  * The lengths are all in rtextents.
315  */
316 STATIC int				/* error */
xfs_rtallocate_extent_exact(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t bno,xfs_extlen_t minlen,xfs_extlen_t maxlen,xfs_extlen_t * len,xfs_buf_t ** rbpp,xfs_fsblock_t * rsb,xfs_extlen_t prod,xfs_rtblock_t * rtblock)317 xfs_rtallocate_extent_exact(
318 	xfs_mount_t	*mp,		/* file system mount point */
319 	xfs_trans_t	*tp,		/* transaction pointer */
320 	xfs_rtblock_t	bno,		/* starting block number to allocate */
321 	xfs_extlen_t	minlen,		/* minimum length to allocate */
322 	xfs_extlen_t	maxlen,		/* maximum length to allocate */
323 	xfs_extlen_t	*len,		/* out: actual length allocated */
324 	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
325 	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
326 	xfs_extlen_t	prod,		/* extent product factor */
327 	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
328 {
329 	int		error;		/* error value */
330 	xfs_extlen_t	i;		/* extent length trimmed due to prod */
331 	int		isfree;		/* extent is free */
332 	xfs_rtblock_t	next;		/* next block to try (dummy) */
333 
334 	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
335 	/*
336 	 * Check if the range in question (for maxlen) is free.
337 	 */
338 	error = xfs_rtcheck_range(mp, tp, bno, maxlen, 1, &next, &isfree);
339 	if (error) {
340 		return error;
341 	}
342 	if (isfree) {
343 		/*
344 		 * If it is, allocate it and return success.
345 		 */
346 		error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
347 		if (error) {
348 			return error;
349 		}
350 		*len = maxlen;
351 		*rtblock = bno;
352 		return 0;
353 	}
354 	/*
355 	 * If not, allocate what there is, if it's at least minlen.
356 	 */
357 	maxlen = next - bno;
358 	if (maxlen < minlen) {
359 		/*
360 		 * Failed, return failure status.
361 		 */
362 		*rtblock = NULLRTBLOCK;
363 		return 0;
364 	}
365 	/*
366 	 * Trim off tail of extent, if prod is specified.
367 	 */
368 	if (prod > 1 && (i = maxlen % prod)) {
369 		maxlen -= i;
370 		if (maxlen < minlen) {
371 			/*
372 			 * Now we can't do it, return failure status.
373 			 */
374 			*rtblock = NULLRTBLOCK;
375 			return 0;
376 		}
377 	}
378 	/*
379 	 * Allocate what we can and return it.
380 	 */
381 	error = xfs_rtallocate_range(mp, tp, bno, maxlen, rbpp, rsb);
382 	if (error) {
383 		return error;
384 	}
385 	*len = maxlen;
386 	*rtblock = bno;
387 	return 0;
388 }
389 
390 /*
391  * Allocate an extent of length minlen<=len<=maxlen, starting as near
392  * to bno as possible.  If we don't get maxlen then use prod to trim
393  * the length, if given.  The lengths are all in rtextents.
394  */
395 STATIC int				/* error */
xfs_rtallocate_extent_near(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t bno,xfs_extlen_t minlen,xfs_extlen_t maxlen,xfs_extlen_t * len,xfs_buf_t ** rbpp,xfs_fsblock_t * rsb,xfs_extlen_t prod,xfs_rtblock_t * rtblock)396 xfs_rtallocate_extent_near(
397 	xfs_mount_t	*mp,		/* file system mount point */
398 	xfs_trans_t	*tp,		/* transaction pointer */
399 	xfs_rtblock_t	bno,		/* starting block number to allocate */
400 	xfs_extlen_t	minlen,		/* minimum length to allocate */
401 	xfs_extlen_t	maxlen,		/* maximum length to allocate */
402 	xfs_extlen_t	*len,		/* out: actual length allocated */
403 	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
404 	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
405 	xfs_extlen_t	prod,		/* extent product factor */
406 	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
407 {
408 	int		any;		/* any useful extents from summary */
409 	xfs_rtblock_t	bbno;		/* bitmap block number */
410 	int		error;		/* error value */
411 	int		i;		/* bitmap block offset (loop control) */
412 	int		j;		/* secondary loop control */
413 	int		log2len;	/* log2 of minlen */
414 	xfs_rtblock_t	n;		/* next block to try */
415 	xfs_rtblock_t	r;		/* result block */
416 
417 	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
418 	/*
419 	 * If the block number given is off the end, silently set it to
420 	 * the last block.
421 	 */
422 	if (bno >= mp->m_sb.sb_rextents)
423 		bno = mp->m_sb.sb_rextents - 1;
424 	/*
425 	 * Try the exact allocation first.
426 	 */
427 	error = xfs_rtallocate_extent_exact(mp, tp, bno, minlen, maxlen, len,
428 		rbpp, rsb, prod, &r);
429 	if (error) {
430 		return error;
431 	}
432 	/*
433 	 * If the exact allocation worked, return that.
434 	 */
435 	if (r != NULLRTBLOCK) {
436 		*rtblock = r;
437 		return 0;
438 	}
439 	bbno = XFS_BITTOBLOCK(mp, bno);
440 	i = 0;
441 	ASSERT(minlen != 0);
442 	log2len = xfs_highbit32(minlen);
443 	/*
444 	 * Loop over all bitmap blocks (bbno + i is current block).
445 	 */
446 	for (;;) {
447 		/*
448 		 * Get summary information of extents of all useful levels
449 		 * starting in this bitmap block.
450 		 */
451 		error = xfs_rtany_summary(mp, tp, log2len, mp->m_rsumlevels - 1,
452 			bbno + i, rbpp, rsb, &any);
453 		if (error) {
454 			return error;
455 		}
456 		/*
457 		 * If there are any useful extents starting here, try
458 		 * allocating one.
459 		 */
460 		if (any) {
461 			/*
462 			 * On the positive side of the starting location.
463 			 */
464 			if (i >= 0) {
465 				/*
466 				 * Try to allocate an extent starting in
467 				 * this block.
468 				 */
469 				error = xfs_rtallocate_extent_block(mp, tp,
470 					bbno + i, minlen, maxlen, len, &n, rbpp,
471 					rsb, prod, &r);
472 				if (error) {
473 					return error;
474 				}
475 				/*
476 				 * If it worked, return it.
477 				 */
478 				if (r != NULLRTBLOCK) {
479 					*rtblock = r;
480 					return 0;
481 				}
482 			}
483 			/*
484 			 * On the negative side of the starting location.
485 			 */
486 			else {		/* i < 0 */
487 				/*
488 				 * Loop backwards through the bitmap blocks from
489 				 * the starting point-1 up to where we are now.
490 				 * There should be an extent which ends in this
491 				 * bitmap block and is long enough.
492 				 */
493 				for (j = -1; j > i; j--) {
494 					/*
495 					 * Grab the summary information for
496 					 * this bitmap block.
497 					 */
498 					error = xfs_rtany_summary(mp, tp,
499 						log2len, mp->m_rsumlevels - 1,
500 						bbno + j, rbpp, rsb, &any);
501 					if (error) {
502 						return error;
503 					}
504 					/*
505 					 * If there's no extent given in the
506 					 * summary that means the extent we
507 					 * found must carry over from an
508 					 * earlier block.  If there is an
509 					 * extent given, we've already tried
510 					 * that allocation, don't do it again.
511 					 */
512 					if (any)
513 						continue;
514 					error = xfs_rtallocate_extent_block(mp,
515 						tp, bbno + j, minlen, maxlen,
516 						len, &n, rbpp, rsb, prod, &r);
517 					if (error) {
518 						return error;
519 					}
520 					/*
521 					 * If it works, return the extent.
522 					 */
523 					if (r != NULLRTBLOCK) {
524 						*rtblock = r;
525 						return 0;
526 					}
527 				}
528 				/*
529 				 * There weren't intervening bitmap blocks
530 				 * with a long enough extent, or the
531 				 * allocation didn't work for some reason
532 				 * (i.e. it's a little * too short).
533 				 * Try to allocate from the summary block
534 				 * that we found.
535 				 */
536 				error = xfs_rtallocate_extent_block(mp, tp,
537 					bbno + i, minlen, maxlen, len, &n, rbpp,
538 					rsb, prod, &r);
539 				if (error) {
540 					return error;
541 				}
542 				/*
543 				 * If it works, return the extent.
544 				 */
545 				if (r != NULLRTBLOCK) {
546 					*rtblock = r;
547 					return 0;
548 				}
549 			}
550 		}
551 		/*
552 		 * Loop control.  If we were on the positive side, and there's
553 		 * still more blocks on the negative side, go there.
554 		 */
555 		if (i > 0 && (int)bbno - i >= 0)
556 			i = -i;
557 		/*
558 		 * If positive, and no more negative, but there are more
559 		 * positive, go there.
560 		 */
561 		else if (i > 0 && (int)bbno + i < mp->m_sb.sb_rbmblocks - 1)
562 			i++;
563 		/*
564 		 * If negative or 0 (just started), and there are positive
565 		 * blocks to go, go there.  The 0 case moves to block 1.
566 		 */
567 		else if (i <= 0 && (int)bbno - i < mp->m_sb.sb_rbmblocks - 1)
568 			i = 1 - i;
569 		/*
570 		 * If negative or 0 and there are more negative blocks,
571 		 * go there.
572 		 */
573 		else if (i <= 0 && (int)bbno + i > 0)
574 			i--;
575 		/*
576 		 * Must be done.  Return failure.
577 		 */
578 		else
579 			break;
580 	}
581 	*rtblock = NULLRTBLOCK;
582 	return 0;
583 }
584 
585 /*
586  * Allocate an extent of length minlen<=len<=maxlen, with no position
587  * specified.  If we don't get maxlen then use prod to trim
588  * the length, if given.  The lengths are all in rtextents.
589  */
590 STATIC int				/* error */
xfs_rtallocate_extent_size(xfs_mount_t * mp,xfs_trans_t * tp,xfs_extlen_t minlen,xfs_extlen_t maxlen,xfs_extlen_t * len,xfs_buf_t ** rbpp,xfs_fsblock_t * rsb,xfs_extlen_t prod,xfs_rtblock_t * rtblock)591 xfs_rtallocate_extent_size(
592 	xfs_mount_t	*mp,		/* file system mount point */
593 	xfs_trans_t	*tp,		/* transaction pointer */
594 	xfs_extlen_t	minlen,		/* minimum length to allocate */
595 	xfs_extlen_t	maxlen,		/* maximum length to allocate */
596 	xfs_extlen_t	*len,		/* out: actual length allocated */
597 	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
598 	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
599 	xfs_extlen_t	prod,		/* extent product factor */
600 	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
601 {
602 	int		error;		/* error value */
603 	int		i;		/* bitmap block number */
604 	int		l;		/* level number (loop control) */
605 	xfs_rtblock_t	n;		/* next block to be tried */
606 	xfs_rtblock_t	r;		/* result block number */
607 	xfs_suminfo_t	sum;		/* summary information for extents */
608 
609 	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
610 	ASSERT(maxlen != 0);
611 
612 	/*
613 	 * Loop over all the levels starting with maxlen.
614 	 * At each level, look at all the bitmap blocks, to see if there
615 	 * are extents starting there that are long enough (>= maxlen).
616 	 * Note, only on the initial level can the allocation fail if
617 	 * the summary says there's an extent.
618 	 */
619 	for (l = xfs_highbit32(maxlen); l < mp->m_rsumlevels; l++) {
620 		/*
621 		 * Loop over all the bitmap blocks.
622 		 */
623 		for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
624 			/*
625 			 * Get the summary for this level/block.
626 			 */
627 			error = xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
628 				&sum);
629 			if (error) {
630 				return error;
631 			}
632 			/*
633 			 * Nothing there, on to the next block.
634 			 */
635 			if (!sum)
636 				continue;
637 			/*
638 			 * Try allocating the extent.
639 			 */
640 			error = xfs_rtallocate_extent_block(mp, tp, i, maxlen,
641 				maxlen, len, &n, rbpp, rsb, prod, &r);
642 			if (error) {
643 				return error;
644 			}
645 			/*
646 			 * If it worked, return that.
647 			 */
648 			if (r != NULLRTBLOCK) {
649 				*rtblock = r;
650 				return 0;
651 			}
652 			/*
653 			 * If the "next block to try" returned from the
654 			 * allocator is beyond the next bitmap block,
655 			 * skip to that bitmap block.
656 			 */
657 			if (XFS_BITTOBLOCK(mp, n) > i + 1)
658 				i = XFS_BITTOBLOCK(mp, n) - 1;
659 		}
660 	}
661 	/*
662 	 * Didn't find any maxlen blocks.  Try smaller ones, unless
663 	 * we're asking for a fixed size extent.
664 	 */
665 	if (minlen > --maxlen) {
666 		*rtblock = NULLRTBLOCK;
667 		return 0;
668 	}
669 	ASSERT(minlen != 0);
670 	ASSERT(maxlen != 0);
671 
672 	/*
673 	 * Loop over sizes, from maxlen down to minlen.
674 	 * This time, when we do the allocations, allow smaller ones
675 	 * to succeed.
676 	 */
677 	for (l = xfs_highbit32(maxlen); l >= xfs_highbit32(minlen); l--) {
678 		/*
679 		 * Loop over all the bitmap blocks, try an allocation
680 		 * starting in that block.
681 		 */
682 		for (i = 0; i < mp->m_sb.sb_rbmblocks; i++) {
683 			/*
684 			 * Get the summary information for this level/block.
685 			 */
686 			error =	xfs_rtget_summary(mp, tp, l, i, rbpp, rsb,
687 						  &sum);
688 			if (error) {
689 				return error;
690 			}
691 			/*
692 			 * If nothing there, go on to next.
693 			 */
694 			if (!sum)
695 				continue;
696 			/*
697 			 * Try the allocation.  Make sure the specified
698 			 * minlen/maxlen are in the possible range for
699 			 * this summary level.
700 			 */
701 			error = xfs_rtallocate_extent_block(mp, tp, i,
702 					XFS_RTMAX(minlen, 1 << l),
703 					XFS_RTMIN(maxlen, (1 << (l + 1)) - 1),
704 					len, &n, rbpp, rsb, prod, &r);
705 			if (error) {
706 				return error;
707 			}
708 			/*
709 			 * If it worked, return that extent.
710 			 */
711 			if (r != NULLRTBLOCK) {
712 				*rtblock = r;
713 				return 0;
714 			}
715 			/*
716 			 * If the "next block to try" returned from the
717 			 * allocator is beyond the next bitmap block,
718 			 * skip to that bitmap block.
719 			 */
720 			if (XFS_BITTOBLOCK(mp, n) > i + 1)
721 				i = XFS_BITTOBLOCK(mp, n) - 1;
722 		}
723 	}
724 	/*
725 	 * Got nothing, return failure.
726 	 */
727 	*rtblock = NULLRTBLOCK;
728 	return 0;
729 }
730 
731 /*
732  * Mark an extent specified by start and len allocated.
733  * Updates all the summary information as well as the bitmap.
734  */
735 STATIC int				/* error */
xfs_rtallocate_range(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t start,xfs_extlen_t len,xfs_buf_t ** rbpp,xfs_fsblock_t * rsb)736 xfs_rtallocate_range(
737 	xfs_mount_t	*mp,		/* file system mount point */
738 	xfs_trans_t	*tp,		/* transaction pointer */
739 	xfs_rtblock_t	start,		/* start block to allocate */
740 	xfs_extlen_t	len,		/* length to allocate */
741 	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
742 	xfs_fsblock_t	*rsb)		/* in/out: summary block number */
743 {
744 	xfs_rtblock_t	end;		/* end of the allocated extent */
745 	int		error;		/* error value */
746 	xfs_rtblock_t	postblock;	/* first block allocated > end */
747 	xfs_rtblock_t	preblock;	/* first block allocated < start */
748 
749 	end = start + len - 1;
750 	/*
751 	 * Assume we're allocating out of the middle of a free extent.
752 	 * We need to find the beginning and end of the extent so we can
753 	 * properly update the summary.
754 	 */
755 	error = xfs_rtfind_back(mp, tp, start, 0, &preblock);
756 	if (error) {
757 		return error;
758 	}
759 	/*
760 	 * Find the next allocated block (end of free extent).
761 	 */
762 	error = xfs_rtfind_forw(mp, tp, end, mp->m_sb.sb_rextents - 1,
763 		&postblock);
764 	if (error) {
765 		return error;
766 	}
767 	/*
768 	 * Decrement the summary information corresponding to the entire
769 	 * (old) free extent.
770 	 */
771 	error = xfs_rtmodify_summary(mp, tp,
772 		XFS_RTBLOCKLOG(postblock + 1 - preblock),
773 		XFS_BITTOBLOCK(mp, preblock), -1, rbpp, rsb);
774 	if (error) {
775 		return error;
776 	}
777 	/*
778 	 * If there are blocks not being allocated at the front of the
779 	 * old extent, add summary data for them to be free.
780 	 */
781 	if (preblock < start) {
782 		error = xfs_rtmodify_summary(mp, tp,
783 			XFS_RTBLOCKLOG(start - preblock),
784 			XFS_BITTOBLOCK(mp, preblock), 1, rbpp, rsb);
785 		if (error) {
786 			return error;
787 		}
788 	}
789 	/*
790 	 * If there are blocks not being allocated at the end of the
791 	 * old extent, add summary data for them to be free.
792 	 */
793 	if (postblock > end) {
794 		error = xfs_rtmodify_summary(mp, tp,
795 			XFS_RTBLOCKLOG(postblock - end),
796 			XFS_BITTOBLOCK(mp, end + 1), 1, rbpp, rsb);
797 		if (error) {
798 			return error;
799 		}
800 	}
801 	/*
802 	 * Modify the bitmap to mark this extent allocated.
803 	 */
804 	error = xfs_rtmodify_range(mp, tp, start, len, 0);
805 	return error;
806 }
807 
808 /*
809  * Return whether there are any free extents in the size range given
810  * by low and high, for the bitmap block bbno.
811  */
812 STATIC int				/* error */
xfs_rtany_summary(xfs_mount_t * mp,xfs_trans_t * tp,int low,int high,xfs_rtblock_t bbno,xfs_buf_t ** rbpp,xfs_fsblock_t * rsb,int * stat)813 xfs_rtany_summary(
814 	xfs_mount_t	*mp,		/* file system mount structure */
815 	xfs_trans_t	*tp,		/* transaction pointer */
816 	int		low,		/* low log2 extent size */
817 	int		high,		/* high log2 extent size */
818 	xfs_rtblock_t	bbno,		/* bitmap block number */
819 	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
820 	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
821 	int		*stat)		/* out: any good extents here? */
822 {
823 	int		error;		/* error value */
824 	int		log;		/* loop counter, log2 of ext. size */
825 	xfs_suminfo_t	sum;		/* summary data */
826 
827 	/*
828 	 * Loop over logs of extent sizes.  Order is irrelevant.
829 	 */
830 	for (log = low; log <= high; log++) {
831 		/*
832 		 * Get one summary datum.
833 		 */
834 		error = xfs_rtget_summary(mp, tp, log, bbno, rbpp, rsb, &sum);
835 		if (error) {
836 			return error;
837 		}
838 		/*
839 		 * If there are any, return success.
840 		 */
841 		if (sum) {
842 			*stat = 1;
843 			return 0;
844 		}
845 	}
846 	/*
847 	 * Found nothing, return failure.
848 	 */
849 	*stat = 0;
850 	return 0;
851 }
852 
853 /*
854  * Get a buffer for the bitmap or summary file block specified.
855  * The buffer is returned read and locked.
856  */
857 STATIC int				/* error */
xfs_rtbuf_get(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t block,int issum,xfs_buf_t ** bpp)858 xfs_rtbuf_get(
859 	xfs_mount_t	*mp,		/* file system mount structure */
860 	xfs_trans_t	*tp,		/* transaction pointer */
861 	xfs_rtblock_t	block,		/* block number in bitmap or summary */
862 	int		issum,		/* is summary not bitmap */
863 	xfs_buf_t	**bpp)		/* output: buffer for the block */
864 {
865 	xfs_buf_t	*bp;		/* block buffer, result */
866 	xfs_daddr_t	d;		/* disk addr of block */
867 	int		error;		/* error value */
868 	xfs_fsblock_t	fsb;		/* fs block number for block */
869 	xfs_inode_t	*ip;		/* bitmap or summary inode */
870 
871 	ip = issum ? mp->m_rsumip : mp->m_rbmip;
872 	/*
873 	 * Map from the file offset (block) and inode number to the
874 	 * file system block.
875 	 */
876 	error = xfs_bmapi_single(tp, ip, XFS_DATA_FORK, &fsb, block);
877 	if (error) {
878 		return error;
879 	}
880 	ASSERT(fsb != NULLFSBLOCK);
881 	/*
882 	 * Convert to disk address for buffer cache.
883 	 */
884 	d = XFS_FSB_TO_DADDR(mp, fsb);
885 	/*
886 	 * Read the buffer.
887 	 */
888 	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
889 				   mp->m_bsize, 0, &bp);
890 	if (error) {
891 		return error;
892 	}
893 	ASSERT(bp && !XFS_BUF_GETERROR(bp));
894 	*bpp = bp;
895 	return 0;
896 }
897 
898 #ifdef DEBUG
899 /*
900  * Check that the given extent (block range) is allocated already.
901  */
902 STATIC int				/* error */
xfs_rtcheck_alloc_range(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t bno,xfs_extlen_t len,int * stat)903 xfs_rtcheck_alloc_range(
904 	xfs_mount_t	*mp,		/* file system mount point */
905 	xfs_trans_t	*tp,		/* transaction pointer */
906 	xfs_rtblock_t	bno,		/* starting block number of extent */
907 	xfs_extlen_t	len,		/* length of extent */
908 	int		*stat)		/* out: 1 for allocated, 0 for not */
909 {
910 	xfs_rtblock_t	new;		/* dummy for xfs_rtcheck_range */
911 
912 	return xfs_rtcheck_range(mp, tp, bno, len, 0, &new, stat);
913 }
914 #endif
915 
916 /*
917  * Check that the given range is either all allocated (val = 0) or
918  * all free (val = 1).
919  */
920 STATIC int				/* error */
xfs_rtcheck_range(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t start,xfs_extlen_t len,int val,xfs_rtblock_t * new,int * stat)921 xfs_rtcheck_range(
922 	xfs_mount_t	*mp,		/* file system mount point */
923 	xfs_trans_t	*tp,		/* transaction pointer */
924 	xfs_rtblock_t	start,		/* starting block number of extent */
925 	xfs_extlen_t	len,		/* length of extent */
926 	int		val,		/* 1 for free, 0 for allocated */
927 	xfs_rtblock_t	*new,		/* out: first block not matching */
928 	int		*stat)		/* out: 1 for matches, 0 for not */
929 {
930 	xfs_rtword_t	*b;		/* current word in buffer */
931 	int		bit;		/* bit number in the word */
932 	xfs_rtblock_t	block;		/* bitmap block number */
933 	xfs_buf_t	*bp;		/* buf for the block */
934 	xfs_rtword_t	*bufp;		/* starting word in buffer */
935 	int		error;		/* error value */
936 	xfs_rtblock_t	i;		/* current bit number rel. to start */
937 	xfs_rtblock_t	lastbit;	/* last useful bit in word */
938 	xfs_rtword_t	mask;		/* mask of relevant bits for value */
939 	xfs_rtword_t	wdiff;		/* difference from wanted value */
940 	int		word;		/* word number in the buffer */
941 
942 	/*
943 	 * Compute starting bitmap block number
944 	 */
945 	block = XFS_BITTOBLOCK(mp, start);
946 	/*
947 	 * Read the bitmap block.
948 	 */
949 	error = xfs_rtbuf_get(mp, tp, block, 0, &bp);
950 	if (error) {
951 		return error;
952 	}
953 	bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
954 	/*
955 	 * Compute the starting word's address, and starting bit.
956 	 */
957 	word = XFS_BITTOWORD(mp, start);
958 	b = &bufp[word];
959 	bit = (int)(start & (XFS_NBWORD - 1));
960 	/*
961 	 * 0 (allocated) => all zero's; 1 (free) => all one's.
962 	 */
963 	val = -val;
964 	/*
965 	 * If not starting on a word boundary, deal with the first
966 	 * (partial) word.
967 	 */
968 	if (bit) {
969 		/*
970 		 * Compute first bit not examined.
971 		 */
972 		lastbit = XFS_RTMIN(bit + len, XFS_NBWORD);
973 		/*
974 		 * Mask of relevant bits.
975 		 */
976 		mask = (((xfs_rtword_t)1 << (lastbit - bit)) - 1) << bit;
977 		/*
978 		 * Compute difference between actual and desired value.
979 		 */
980 		if ((wdiff = (*b ^ val) & mask)) {
981 			/*
982 			 * Different, compute first wrong bit and return.
983 			 */
984 			xfs_trans_brelse(tp, bp);
985 			i = XFS_RTLOBIT(wdiff) - bit;
986 			*new = start + i;
987 			*stat = 0;
988 			return 0;
989 		}
990 		i = lastbit - bit;
991 		/*
992 		 * Go on to next block if that's where the next word is
993 		 * and we need the next word.
994 		 */
995 		if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
996 			/*
997 			 * If done with this block, get the next one.
998 			 */
999 			xfs_trans_brelse(tp, bp);
1000 			error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
1001 			if (error) {
1002 				return error;
1003 			}
1004 			b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1005 			word = 0;
1006 		} else {
1007 			/*
1008 			 * Go on to the next word in the buffer.
1009 			 */
1010 			b++;
1011 		}
1012 	} else {
1013 		/*
1014 		 * Starting on a word boundary, no partial word.
1015 		 */
1016 		i = 0;
1017 	}
1018 	/*
1019 	 * Loop over whole words in buffers.  When we use up one buffer
1020 	 * we move on to the next one.
1021 	 */
1022 	while (len - i >= XFS_NBWORD) {
1023 		/*
1024 		 * Compute difference between actual and desired value.
1025 		 */
1026 		if ((wdiff = *b ^ val)) {
1027 			/*
1028 			 * Different, compute first wrong bit and return.
1029 			 */
1030 			xfs_trans_brelse(tp, bp);
1031 			i += XFS_RTLOBIT(wdiff);
1032 			*new = start + i;
1033 			*stat = 0;
1034 			return 0;
1035 		}
1036 		i += XFS_NBWORD;
1037 		/*
1038 		 * Go on to next block if that's where the next word is
1039 		 * and we need the next word.
1040 		 */
1041 		if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
1042 			/*
1043 			 * If done with this block, get the next one.
1044 			 */
1045 			xfs_trans_brelse(tp, bp);
1046 			error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
1047 			if (error) {
1048 				return error;
1049 			}
1050 			b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1051 			word = 0;
1052 		} else {
1053 			/*
1054 			 * Go on to the next word in the buffer.
1055 			 */
1056 			b++;
1057 		}
1058 	}
1059 	/*
1060 	 * If not ending on a word boundary, deal with the last
1061 	 * (partial) word.
1062 	 */
1063 	if ((lastbit = len - i)) {
1064 		/*
1065 		 * Mask of relevant bits.
1066 		 */
1067 		mask = ((xfs_rtword_t)1 << lastbit) - 1;
1068 		/*
1069 		 * Compute difference between actual and desired value.
1070 		 */
1071 		if ((wdiff = (*b ^ val) & mask)) {
1072 			/*
1073 			 * Different, compute first wrong bit and return.
1074 			 */
1075 			xfs_trans_brelse(tp, bp);
1076 			i += XFS_RTLOBIT(wdiff);
1077 			*new = start + i;
1078 			*stat = 0;
1079 			return 0;
1080 		} else
1081 			i = len;
1082 	}
1083 	/*
1084 	 * Successful, return.
1085 	 */
1086 	xfs_trans_brelse(tp, bp);
1087 	*new = start + i;
1088 	*stat = 1;
1089 	return 0;
1090 }
1091 
1092 /*
1093  * Copy and transform the summary file, given the old and new
1094  * parameters in the mount structures.
1095  */
1096 STATIC int				/* error */
xfs_rtcopy_summary(xfs_mount_t * omp,xfs_mount_t * nmp,xfs_trans_t * tp)1097 xfs_rtcopy_summary(
1098 	xfs_mount_t	*omp,		/* old file system mount point */
1099 	xfs_mount_t	*nmp,		/* new file system mount point */
1100 	xfs_trans_t	*tp)		/* transaction pointer */
1101 {
1102 	xfs_rtblock_t	bbno;		/* bitmap block number */
1103 	xfs_buf_t	*bp;		/* summary buffer */
1104 	int		error;		/* error return value */
1105 	int		log;		/* summary level number (log length) */
1106 	xfs_suminfo_t	sum;		/* summary data */
1107 	xfs_fsblock_t	sumbno;		/* summary block number */
1108 
1109 	bp = NULL;
1110 	for (log = omp->m_rsumlevels - 1; log >= 0; log--) {
1111 		for (bbno = omp->m_sb.sb_rbmblocks - 1;
1112 		     (xfs_srtblock_t)bbno >= 0;
1113 		     bbno--) {
1114 			error = xfs_rtget_summary(omp, tp, log, bbno, &bp,
1115 				&sumbno, &sum);
1116 			if (error)
1117 				return error;
1118 			if (sum == 0)
1119 				continue;
1120 			error = xfs_rtmodify_summary(omp, tp, log, bbno, -sum,
1121 				&bp, &sumbno);
1122 			if (error)
1123 				return error;
1124 			error = xfs_rtmodify_summary(nmp, tp, log, bbno, sum,
1125 				&bp, &sumbno);
1126 			if (error)
1127 				return error;
1128 			ASSERT(sum > 0);
1129 		}
1130 	}
1131 	return 0;
1132 }
1133 
1134 /*
1135  * Searching backward from start to limit, find the first block whose
1136  * allocated/free state is different from start's.
1137  */
1138 STATIC int				/* error */
xfs_rtfind_back(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t start,xfs_rtblock_t limit,xfs_rtblock_t * rtblock)1139 xfs_rtfind_back(
1140 	xfs_mount_t	*mp,		/* file system mount point */
1141 	xfs_trans_t	*tp,		/* transaction pointer */
1142 	xfs_rtblock_t	start,		/* starting block to look at */
1143 	xfs_rtblock_t	limit,		/* last block to look at */
1144 	xfs_rtblock_t	*rtblock)	/* out: start block found */
1145 {
1146 	xfs_rtword_t	*b;		/* current word in buffer */
1147 	int		bit;		/* bit number in the word */
1148 	xfs_rtblock_t	block;		/* bitmap block number */
1149 	xfs_buf_t	*bp;		/* buf for the block */
1150 	xfs_rtword_t	*bufp;		/* starting word in buffer */
1151 	int		error;		/* error value */
1152 	xfs_rtblock_t	firstbit;	/* first useful bit in the word */
1153 	xfs_rtblock_t	i;		/* current bit number rel. to start */
1154 	xfs_rtblock_t	len;		/* length of inspected area */
1155 	xfs_rtword_t	mask;		/* mask of relevant bits for value */
1156 	xfs_rtword_t	want;		/* mask for "good" values */
1157 	xfs_rtword_t	wdiff;		/* difference from wanted value */
1158 	int		word;		/* word number in the buffer */
1159 
1160 	/*
1161 	 * Compute and read in starting bitmap block for starting block.
1162 	 */
1163 	block = XFS_BITTOBLOCK(mp, start);
1164 	error = xfs_rtbuf_get(mp, tp, block, 0, &bp);
1165 	if (error) {
1166 		return error;
1167 	}
1168 	bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1169 	/*
1170 	 * Get the first word's index & point to it.
1171 	 */
1172 	word = XFS_BITTOWORD(mp, start);
1173 	b = &bufp[word];
1174 	bit = (int)(start & (XFS_NBWORD - 1));
1175 	len = start - limit + 1;
1176 	/*
1177 	 * Compute match value, based on the bit at start: if 1 (free)
1178 	 * then all-ones, else all-zeroes.
1179 	 */
1180 	want = (*b & ((xfs_rtword_t)1 << bit)) ? -1 : 0;
1181 	/*
1182 	 * If the starting position is not word-aligned, deal with the
1183 	 * partial word.
1184 	 */
1185 	if (bit < XFS_NBWORD - 1) {
1186 		/*
1187 		 * Calculate first (leftmost) bit number to look at,
1188 		 * and mask for all the relevant bits in this word.
1189 		 */
1190 		firstbit = XFS_RTMAX((xfs_srtblock_t)(bit - len + 1), 0);
1191 		mask = (((xfs_rtword_t)1 << (bit - firstbit + 1)) - 1) <<
1192 			firstbit;
1193 		/*
1194 		 * Calculate the difference between the value there
1195 		 * and what we're looking for.
1196 		 */
1197 		if ((wdiff = (*b ^ want) & mask)) {
1198 			/*
1199 			 * Different.  Mark where we are and return.
1200 			 */
1201 			xfs_trans_brelse(tp, bp);
1202 			i = bit - XFS_RTHIBIT(wdiff);
1203 			*rtblock = start - i + 1;
1204 			return 0;
1205 		}
1206 		i = bit - firstbit + 1;
1207 		/*
1208 		 * Go on to previous block if that's where the previous word is
1209 		 * and we need the previous word.
1210 		 */
1211 		if (--word == -1 && i < len) {
1212 			/*
1213 			 * If done with this block, get the previous one.
1214 			 */
1215 			xfs_trans_brelse(tp, bp);
1216 			error = xfs_rtbuf_get(mp, tp, --block, 0, &bp);
1217 			if (error) {
1218 				return error;
1219 			}
1220 			bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1221 			word = XFS_BLOCKWMASK(mp);
1222 			b = &bufp[word];
1223 		} else {
1224 			/*
1225 			 * Go on to the previous word in the buffer.
1226 			 */
1227 			b--;
1228 		}
1229 	} else {
1230 		/*
1231 		 * Starting on a word boundary, no partial word.
1232 		 */
1233 		i = 0;
1234 	}
1235 	/*
1236 	 * Loop over whole words in buffers.  When we use up one buffer
1237 	 * we move on to the previous one.
1238 	 */
1239 	while (len - i >= XFS_NBWORD) {
1240 		/*
1241 		 * Compute difference between actual and desired value.
1242 		 */
1243 		if ((wdiff = *b ^ want)) {
1244 			/*
1245 			 * Different, mark where we are and return.
1246 			 */
1247 			xfs_trans_brelse(tp, bp);
1248 			i += XFS_NBWORD - 1 - XFS_RTHIBIT(wdiff);
1249 			*rtblock = start - i + 1;
1250 			return 0;
1251 		}
1252 		i += XFS_NBWORD;
1253 		/*
1254 		 * Go on to previous block if that's where the previous word is
1255 		 * and we need the previous word.
1256 		 */
1257 		if (--word == -1 && i < len) {
1258 			/*
1259 			 * If done with this block, get the previous one.
1260 			 */
1261 			xfs_trans_brelse(tp, bp);
1262 			error = xfs_rtbuf_get(mp, tp, --block, 0, &bp);
1263 			if (error) {
1264 				return error;
1265 			}
1266 			bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1267 			word = XFS_BLOCKWMASK(mp);
1268 			b = &bufp[word];
1269 		} else {
1270 			/*
1271 			 * Go on to the previous word in the buffer.
1272 			 */
1273 			b--;
1274 		}
1275 	}
1276 	/*
1277 	 * If not ending on a word boundary, deal with the last
1278 	 * (partial) word.
1279 	 */
1280 	if (len - i) {
1281 		/*
1282 		 * Calculate first (leftmost) bit number to look at,
1283 		 * and mask for all the relevant bits in this word.
1284 		 */
1285 		firstbit = XFS_NBWORD - (len - i);
1286 		mask = (((xfs_rtword_t)1 << (len - i)) - 1) << firstbit;
1287 		/*
1288 		 * Compute difference between actual and desired value.
1289 		 */
1290 		if ((wdiff = (*b ^ want) & mask)) {
1291 			/*
1292 			 * Different, mark where we are and return.
1293 			 */
1294 			xfs_trans_brelse(tp, bp);
1295 			i += XFS_NBWORD - 1 - XFS_RTHIBIT(wdiff);
1296 			*rtblock = start - i + 1;
1297 			return 0;
1298 		} else
1299 			i = len;
1300 	}
1301 	/*
1302 	 * No match, return that we scanned the whole area.
1303 	 */
1304 	xfs_trans_brelse(tp, bp);
1305 	*rtblock = start - i + 1;
1306 	return 0;
1307 }
1308 
1309 /*
1310  * Searching forward from start to limit, find the first block whose
1311  * allocated/free state is different from start's.
1312  */
1313 STATIC int				/* error */
xfs_rtfind_forw(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t start,xfs_rtblock_t limit,xfs_rtblock_t * rtblock)1314 xfs_rtfind_forw(
1315 	xfs_mount_t	*mp,		/* file system mount point */
1316 	xfs_trans_t	*tp,		/* transaction pointer */
1317 	xfs_rtblock_t	start,		/* starting block to look at */
1318 	xfs_rtblock_t	limit,		/* last block to look at */
1319 	xfs_rtblock_t	*rtblock)	/* out: start block found */
1320 {
1321 	xfs_rtword_t	*b;		/* current word in buffer */
1322 	int		bit;		/* bit number in the word */
1323 	xfs_rtblock_t	block;		/* bitmap block number */
1324 	xfs_buf_t	*bp;		/* buf for the block */
1325 	xfs_rtword_t	*bufp;		/* starting word in buffer */
1326 	int		error;		/* error value */
1327 	xfs_rtblock_t	i;		/* current bit number rel. to start */
1328 	xfs_rtblock_t	lastbit;	/* last useful bit in the word */
1329 	xfs_rtblock_t	len;		/* length of inspected area */
1330 	xfs_rtword_t	mask;		/* mask of relevant bits for value */
1331 	xfs_rtword_t	want;		/* mask for "good" values */
1332 	xfs_rtword_t	wdiff;		/* difference from wanted value */
1333 	int		word;		/* word number in the buffer */
1334 
1335 	/*
1336 	 * Compute and read in starting bitmap block for starting block.
1337 	 */
1338 	block = XFS_BITTOBLOCK(mp, start);
1339 	error = xfs_rtbuf_get(mp, tp, block, 0, &bp);
1340 	if (error) {
1341 		return error;
1342 	}
1343 	bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1344 	/*
1345 	 * Get the first word's index & point to it.
1346 	 */
1347 	word = XFS_BITTOWORD(mp, start);
1348 	b = &bufp[word];
1349 	bit = (int)(start & (XFS_NBWORD - 1));
1350 	len = limit - start + 1;
1351 	/*
1352 	 * Compute match value, based on the bit at start: if 1 (free)
1353 	 * then all-ones, else all-zeroes.
1354 	 */
1355 	want = (*b & ((xfs_rtword_t)1 << bit)) ? -1 : 0;
1356 	/*
1357 	 * If the starting position is not word-aligned, deal with the
1358 	 * partial word.
1359 	 */
1360 	if (bit) {
1361 		/*
1362 		 * Calculate last (rightmost) bit number to look at,
1363 		 * and mask for all the relevant bits in this word.
1364 		 */
1365 		lastbit = XFS_RTMIN(bit + len, XFS_NBWORD);
1366 		mask = (((xfs_rtword_t)1 << (lastbit - bit)) - 1) << bit;
1367 		/*
1368 		 * Calculate the difference between the value there
1369 		 * and what we're looking for.
1370 		 */
1371 		if ((wdiff = (*b ^ want) & mask)) {
1372 			/*
1373 			 * Different.  Mark where we are and return.
1374 			 */
1375 			xfs_trans_brelse(tp, bp);
1376 			i = XFS_RTLOBIT(wdiff) - bit;
1377 			*rtblock = start + i - 1;
1378 			return 0;
1379 		}
1380 		i = lastbit - bit;
1381 		/*
1382 		 * Go on to next block if that's where the next word is
1383 		 * and we need the next word.
1384 		 */
1385 		if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
1386 			/*
1387 			 * If done with this block, get the previous one.
1388 			 */
1389 			xfs_trans_brelse(tp, bp);
1390 			error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
1391 			if (error) {
1392 				return error;
1393 			}
1394 			b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1395 			word = 0;
1396 		} else {
1397 			/*
1398 			 * Go on to the previous word in the buffer.
1399 			 */
1400 			b++;
1401 		}
1402 	} else {
1403 		/*
1404 		 * Starting on a word boundary, no partial word.
1405 		 */
1406 		i = 0;
1407 	}
1408 	/*
1409 	 * Loop over whole words in buffers.  When we use up one buffer
1410 	 * we move on to the next one.
1411 	 */
1412 	while (len - i >= XFS_NBWORD) {
1413 		/*
1414 		 * Compute difference between actual and desired value.
1415 		 */
1416 		if ((wdiff = *b ^ want)) {
1417 			/*
1418 			 * Different, mark where we are and return.
1419 			 */
1420 			xfs_trans_brelse(tp, bp);
1421 			i += XFS_RTLOBIT(wdiff);
1422 			*rtblock = start + i - 1;
1423 			return 0;
1424 		}
1425 		i += XFS_NBWORD;
1426 		/*
1427 		 * Go on to next block if that's where the next word is
1428 		 * and we need the next word.
1429 		 */
1430 		if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
1431 			/*
1432 			 * If done with this block, get the next one.
1433 			 */
1434 			xfs_trans_brelse(tp, bp);
1435 			error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
1436 			if (error) {
1437 				return error;
1438 			}
1439 			b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1440 			word = 0;
1441 		} else {
1442 			/*
1443 			 * Go on to the next word in the buffer.
1444 			 */
1445 			b++;
1446 		}
1447 	}
1448 	/*
1449 	 * If not ending on a word boundary, deal with the last
1450 	 * (partial) word.
1451 	 */
1452 	if ((lastbit = len - i)) {
1453 		/*
1454 		 * Calculate mask for all the relevant bits in this word.
1455 		 */
1456 		mask = ((xfs_rtword_t)1 << lastbit) - 1;
1457 		/*
1458 		 * Compute difference between actual and desired value.
1459 		 */
1460 		if ((wdiff = (*b ^ want) & mask)) {
1461 			/*
1462 			 * Different, mark where we are and return.
1463 			 */
1464 			xfs_trans_brelse(tp, bp);
1465 			i += XFS_RTLOBIT(wdiff);
1466 			*rtblock = start + i - 1;
1467 			return 0;
1468 		} else
1469 			i = len;
1470 	}
1471 	/*
1472 	 * No match, return that we scanned the whole area.
1473 	 */
1474 	xfs_trans_brelse(tp, bp);
1475 	*rtblock = start + i - 1;
1476 	return 0;
1477 }
1478 
1479 /*
1480  * Mark an extent specified by start and len freed.
1481  * Updates all the summary information as well as the bitmap.
1482  */
1483 STATIC int				/* error */
xfs_rtfree_range(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t start,xfs_extlen_t len,xfs_buf_t ** rbpp,xfs_fsblock_t * rsb)1484 xfs_rtfree_range(
1485 	xfs_mount_t	*mp,		/* file system mount point */
1486 	xfs_trans_t	*tp,		/* transaction pointer */
1487 	xfs_rtblock_t	start,		/* starting block to free */
1488 	xfs_extlen_t	len,		/* length to free */
1489 	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
1490 	xfs_fsblock_t	*rsb)		/* in/out: summary block number */
1491 {
1492 	xfs_rtblock_t	end;		/* end of the freed extent */
1493 	int		error;		/* error value */
1494 	xfs_rtblock_t	postblock;	/* first block freed > end */
1495 	xfs_rtblock_t	preblock;	/* first block freed < start */
1496 
1497 	end = start + len - 1;
1498 	/*
1499 	 * Modify the bitmap to mark this extent freed.
1500 	 */
1501 	error = xfs_rtmodify_range(mp, tp, start, len, 1);
1502 	if (error) {
1503 		return error;
1504 	}
1505 	/*
1506 	 * Assume we're freeing out of the middle of an allocated extent.
1507 	 * We need to find the beginning and end of the extent so we can
1508 	 * properly update the summary.
1509 	 */
1510 	error = xfs_rtfind_back(mp, tp, start, 0, &preblock);
1511 	if (error) {
1512 		return error;
1513 	}
1514 	/*
1515 	 * Find the next allocated block (end of allocated extent).
1516 	 */
1517 	error = xfs_rtfind_forw(mp, tp, end, mp->m_sb.sb_rextents - 1,
1518 		&postblock);
1519 	/*
1520 	 * If there are blocks not being freed at the front of the
1521 	 * old extent, add summary data for them to be allocated.
1522 	 */
1523 	if (preblock < start) {
1524 		error = xfs_rtmodify_summary(mp, tp,
1525 			XFS_RTBLOCKLOG(start - preblock),
1526 			XFS_BITTOBLOCK(mp, preblock), -1, rbpp, rsb);
1527 		if (error) {
1528 			return error;
1529 		}
1530 	}
1531 	/*
1532 	 * If there are blocks not being freed at the end of the
1533 	 * old extent, add summary data for them to be allocated.
1534 	 */
1535 	if (postblock > end) {
1536 		error = xfs_rtmodify_summary(mp, tp,
1537 			XFS_RTBLOCKLOG(postblock - end),
1538 			XFS_BITTOBLOCK(mp, end + 1), -1, rbpp, rsb);
1539 		if (error) {
1540 			return error;
1541 		}
1542 	}
1543 	/*
1544 	 * Increment the summary information corresponding to the entire
1545 	 * (new) free extent.
1546 	 */
1547 	error = xfs_rtmodify_summary(mp, tp,
1548 		XFS_RTBLOCKLOG(postblock + 1 - preblock),
1549 		XFS_BITTOBLOCK(mp, preblock), 1, rbpp, rsb);
1550 	return error;
1551 }
1552 
1553 /*
1554  * Read and return the summary information for a given extent size,
1555  * bitmap block combination.
1556  * Keeps track of a current summary block, so we don't keep reading
1557  * it from the buffer cache.
1558  */
1559 STATIC int				/* error */
xfs_rtget_summary(xfs_mount_t * mp,xfs_trans_t * tp,int log,xfs_rtblock_t bbno,xfs_buf_t ** rbpp,xfs_fsblock_t * rsb,xfs_suminfo_t * sum)1560 xfs_rtget_summary(
1561 	xfs_mount_t	*mp,		/* file system mount structure */
1562 	xfs_trans_t	*tp,		/* transaction pointer */
1563 	int		log,		/* log2 of extent size */
1564 	xfs_rtblock_t	bbno,		/* bitmap block number */
1565 	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
1566 	xfs_fsblock_t	*rsb,		/* in/out: summary block number */
1567 	xfs_suminfo_t	*sum)		/* out: summary info for this block */
1568 {
1569 	xfs_buf_t	*bp;		/* buffer for summary block */
1570 	int		error;		/* error value */
1571 	xfs_fsblock_t	sb;		/* summary fsblock */
1572 	int		so;		/* index into the summary file */
1573 	xfs_suminfo_t	*sp;		/* pointer to returned data */
1574 
1575 	/*
1576 	 * Compute entry number in the summary file.
1577 	 */
1578 	so = XFS_SUMOFFS(mp, log, bbno);
1579 	/*
1580 	 * Compute the block number in the summary file.
1581 	 */
1582 	sb = XFS_SUMOFFSTOBLOCK(mp, so);
1583 	/*
1584 	 * If we have an old buffer, and the block number matches, use that.
1585 	 */
1586 	if (rbpp && *rbpp && *rsb == sb)
1587 		bp = *rbpp;
1588 	/*
1589 	 * Otherwise we have to get the buffer.
1590 	 */
1591 	else {
1592 		/*
1593 		 * If there was an old one, get rid of it first.
1594 		 */
1595 		if (rbpp && *rbpp)
1596 			xfs_trans_brelse(tp, *rbpp);
1597 		error = xfs_rtbuf_get(mp, tp, sb, 1, &bp);
1598 		if (error) {
1599 			return error;
1600 		}
1601 		/*
1602 		 * Remember this buffer and block for the next call.
1603 		 */
1604 		if (rbpp) {
1605 			*rbpp = bp;
1606 			*rsb = sb;
1607 		}
1608 	}
1609 	/*
1610 	 * Point to the summary information & copy it out.
1611 	 */
1612 	sp = XFS_SUMPTR(mp, bp, so);
1613 	*sum = *sp;
1614 	/*
1615 	 * Drop the buffer if we're not asked to remember it.
1616 	 */
1617 	if (!rbpp)
1618 		xfs_trans_brelse(tp, bp);
1619 	return 0;
1620 }
1621 
1622 /*
1623  * Set the given range of bitmap bits to the given value.
1624  * Do whatever I/O and logging is required.
1625  */
1626 STATIC int				/* error */
xfs_rtmodify_range(xfs_mount_t * mp,xfs_trans_t * tp,xfs_rtblock_t start,xfs_extlen_t len,int val)1627 xfs_rtmodify_range(
1628 	xfs_mount_t	*mp,		/* file system mount point */
1629 	xfs_trans_t	*tp,		/* transaction pointer */
1630 	xfs_rtblock_t	start,		/* starting block to modify */
1631 	xfs_extlen_t	len,		/* length of extent to modify */
1632 	int		val)		/* 1 for free, 0 for allocated */
1633 {
1634 	xfs_rtword_t	*b;		/* current word in buffer */
1635 	int		bit;		/* bit number in the word */
1636 	xfs_rtblock_t	block;		/* bitmap block number */
1637 	xfs_buf_t	*bp;		/* buf for the block */
1638 	xfs_rtword_t	*bufp;		/* starting word in buffer */
1639 	int		error;		/* error value */
1640 	xfs_rtword_t	*first;		/* first used word in the buffer */
1641 	int		i;		/* current bit number rel. to start */
1642 	int		lastbit;	/* last useful bit in word */
1643 	xfs_rtword_t	mask;		/* mask o frelevant bits for value */
1644 	int		word;		/* word number in the buffer */
1645 
1646 	/*
1647 	 * Compute starting bitmap block number.
1648 	 */
1649 	block = XFS_BITTOBLOCK(mp, start);
1650 	/*
1651 	 * Read the bitmap block, and point to its data.
1652 	 */
1653 	error = xfs_rtbuf_get(mp, tp, block, 0, &bp);
1654 	if (error) {
1655 		return error;
1656 	}
1657 	bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1658 	/*
1659 	 * Compute the starting word's address, and starting bit.
1660 	 */
1661 	word = XFS_BITTOWORD(mp, start);
1662 	first = b = &bufp[word];
1663 	bit = (int)(start & (XFS_NBWORD - 1));
1664 	/*
1665 	 * 0 (allocated) => all zeroes; 1 (free) => all ones.
1666 	 */
1667 	val = -val;
1668 	/*
1669 	 * If not starting on a word boundary, deal with the first
1670 	 * (partial) word.
1671 	 */
1672 	if (bit) {
1673 		/*
1674 		 * Compute first bit not changed and mask of relevant bits.
1675 		 */
1676 		lastbit = XFS_RTMIN(bit + len, XFS_NBWORD);
1677 		mask = (((xfs_rtword_t)1 << (lastbit - bit)) - 1) << bit;
1678 		/*
1679 		 * Set/clear the active bits.
1680 		 */
1681 		if (val)
1682 			*b |= mask;
1683 		else
1684 			*b &= ~mask;
1685 		i = lastbit - bit;
1686 		/*
1687 		 * Go on to the next block if that's where the next word is
1688 		 * and we need the next word.
1689 		 */
1690 		if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
1691 			/*
1692 			 * Log the changed part of this block.
1693 			 * Get the next one.
1694 			 */
1695 			xfs_trans_log_buf(tp, bp,
1696 				(uint)((char *)first - (char *)bufp),
1697 				(uint)((char *)b - (char *)bufp));
1698 			error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
1699 			if (error) {
1700 				return error;
1701 			}
1702 			first = b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1703 			word = 0;
1704 		} else {
1705 			/*
1706 			 * Go on to the next word in the buffer
1707 			 */
1708 			b++;
1709 		}
1710 	} else {
1711 		/*
1712 		 * Starting on a word boundary, no partial word.
1713 		 */
1714 		i = 0;
1715 	}
1716 	/*
1717 	 * Loop over whole words in buffers.  When we use up one buffer
1718 	 * we move on to the next one.
1719 	 */
1720 	while (len - i >= XFS_NBWORD) {
1721 		/*
1722 		 * Set the word value correctly.
1723 		 */
1724 		*b = val;
1725 		i += XFS_NBWORD;
1726 		/*
1727 		 * Go on to the next block if that's where the next word is
1728 		 * and we need the next word.
1729 		 */
1730 		if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
1731 			/*
1732 			 * Log the changed part of this block.
1733 			 * Get the next one.
1734 			 */
1735 			xfs_trans_log_buf(tp, bp,
1736 				(uint)((char *)first - (char *)bufp),
1737 				(uint)((char *)b - (char *)bufp));
1738 			error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
1739 			if (error) {
1740 				return error;
1741 			}
1742 			first = b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
1743 			word = 0;
1744 		} else {
1745 			/*
1746 			 * Go on to the next word in the buffer
1747 			 */
1748 			b++;
1749 		}
1750 	}
1751 	/*
1752 	 * If not ending on a word boundary, deal with the last
1753 	 * (partial) word.
1754 	 */
1755 	if ((lastbit = len - i)) {
1756 		/*
1757 		 * Compute a mask of relevant bits.
1758 		 */
1759 		bit = 0;
1760 		mask = ((xfs_rtword_t)1 << lastbit) - 1;
1761 		/*
1762 		 * Set/clear the active bits.
1763 		 */
1764 		if (val)
1765 			*b |= mask;
1766 		else
1767 			*b &= ~mask;
1768 		b++;
1769 	}
1770 	/*
1771 	 * Log any remaining changed bytes.
1772 	 */
1773 	if (b > first)
1774 		xfs_trans_log_buf(tp, bp, (uint)((char *)first - (char *)bufp),
1775 			(uint)((char *)b - (char *)bufp - 1));
1776 	return 0;
1777 }
1778 
1779 /*
1780  * Read and modify the summary information for a given extent size,
1781  * bitmap block combination.
1782  * Keeps track of a current summary block, so we don't keep reading
1783  * it from the buffer cache.
1784  */
1785 STATIC int				/* error */
xfs_rtmodify_summary(xfs_mount_t * mp,xfs_trans_t * tp,int log,xfs_rtblock_t bbno,int delta,xfs_buf_t ** rbpp,xfs_fsblock_t * rsb)1786 xfs_rtmodify_summary(
1787 	xfs_mount_t	*mp,		/* file system mount point */
1788 	xfs_trans_t	*tp,		/* transaction pointer */
1789 	int		log,		/* log2 of extent size */
1790 	xfs_rtblock_t	bbno,		/* bitmap block number */
1791 	int		delta,		/* change to make to summary info */
1792 	xfs_buf_t	**rbpp,		/* in/out: summary block buffer */
1793 	xfs_fsblock_t	*rsb)		/* in/out: summary block number */
1794 {
1795 	xfs_buf_t	*bp;		/* buffer for the summary block */
1796 	int		error;		/* error value */
1797 	xfs_fsblock_t	sb;		/* summary fsblock */
1798 	int		so;		/* index into the summary file */
1799 	xfs_suminfo_t	*sp;		/* pointer to returned data */
1800 
1801 	/*
1802 	 * Compute entry number in the summary file.
1803 	 */
1804 	so = XFS_SUMOFFS(mp, log, bbno);
1805 	/*
1806 	 * Compute the block number in the summary file.
1807 	 */
1808 	sb = XFS_SUMOFFSTOBLOCK(mp, so);
1809 	/*
1810 	 * If we have an old buffer, and the block number matches, use that.
1811 	 */
1812 	if (rbpp && *rbpp && *rsb == sb)
1813 		bp = *rbpp;
1814 	/*
1815 	 * Otherwise we have to get the buffer.
1816 	 */
1817 	else {
1818 		/*
1819 		 * If there was an old one, get rid of it first.
1820 		 */
1821 		if (rbpp && *rbpp)
1822 			xfs_trans_brelse(tp, *rbpp);
1823 		error = xfs_rtbuf_get(mp, tp, sb, 1, &bp);
1824 		if (error) {
1825 			return error;
1826 		}
1827 		/*
1828 		 * Remember this buffer and block for the next call.
1829 		 */
1830 		if (rbpp) {
1831 			*rbpp = bp;
1832 			*rsb = sb;
1833 		}
1834 	}
1835 	/*
1836 	 * Point to the summary information, modify and log it.
1837 	 */
1838 	sp = XFS_SUMPTR(mp, bp, so);
1839 	*sp += delta;
1840 	xfs_trans_log_buf(tp, bp, (uint)((char *)sp - (char *)XFS_BUF_PTR(bp)),
1841 		(uint)((char *)sp - (char *)XFS_BUF_PTR(bp) + sizeof(*sp) - 1));
1842 	return 0;
1843 }
1844 
1845 /*
1846  * Visible (exported) functions.
1847  */
1848 
1849 /*
1850  * Grow the realtime area of the filesystem.
1851  */
1852 int
xfs_growfs_rt(xfs_mount_t * mp,xfs_growfs_rt_t * in)1853 xfs_growfs_rt(
1854 	xfs_mount_t	*mp,		/* mount point for filesystem */
1855 	xfs_growfs_rt_t	*in)		/* growfs rt input struct */
1856 {
1857 	xfs_rtblock_t	bmbno;		/* bitmap block number */
1858 	xfs_buf_t	*bp;		/* temporary buffer */
1859 	int		error;		/* error return value */
1860 	xfs_inode_t	*ip;		/* bitmap inode, used as lock */
1861 	xfs_mount_t	*nmp;		/* new (fake) mount structure */
1862 	xfs_drfsbno_t	nrblocks;	/* new number of realtime blocks */
1863 	xfs_extlen_t	nrbmblocks;	/* new number of rt bitmap blocks */
1864 	xfs_drtbno_t	nrextents;	/* new number of realtime extents */
1865 	uint8_t		nrextslog;	/* new log2 of sb_rextents */
1866 	xfs_extlen_t	nrsumblocks;	/* new number of summary blocks */
1867 	uint		nrsumlevels;	/* new rt summary levels */
1868 	uint		nrsumsize;	/* new size of rt summary, bytes */
1869 	xfs_sb_t	*nsbp;		/* new superblock */
1870 	xfs_extlen_t	rbmblocks;	/* current number of rt bitmap blocks */
1871 	xfs_extlen_t	rsumblocks;	/* current number of rt summary blks */
1872 	xfs_sb_t	*sbp;		/* old superblock */
1873 	xfs_fsblock_t	sumbno;		/* summary block number */
1874 
1875 	sbp = &mp->m_sb;
1876 	/*
1877 	 * Initial error checking.
1878 	 */
1879 	if (!capable(CAP_SYS_ADMIN))
1880 		return XFS_ERROR(EPERM);
1881 	if (mp->m_rtdev_targp == NULL || mp->m_rbmip == NULL ||
1882 	    (nrblocks = in->newblocks) <= sbp->sb_rblocks ||
1883 	    (sbp->sb_rblocks && (in->extsize != sbp->sb_rextsize)))
1884 		return XFS_ERROR(EINVAL);
1885 	if ((error = xfs_sb_validate_fsb_count(sbp, nrblocks)))
1886 		return error;
1887 	/*
1888 	 * Read in the last block of the device, make sure it exists.
1889 	 */
1890 	error = xfs_read_buf(mp, mp->m_rtdev_targp,
1891 			XFS_FSB_TO_BB(mp, nrblocks - 1),
1892 			XFS_FSB_TO_BB(mp, 1), 0, &bp);
1893 	if (error)
1894 		return error;
1895 	ASSERT(bp);
1896 	xfs_buf_relse(bp);
1897 	/*
1898 	 * Calculate new parameters.  These are the final values to be reached.
1899 	 */
1900 	nrextents = nrblocks;
1901 	do_div(nrextents, in->extsize);
1902 	nrbmblocks = howmany_64(nrextents, NBBY * sbp->sb_blocksize);
1903 	nrextslog = xfs_highbit32(nrextents);
1904 	nrsumlevels = nrextslog + 1;
1905 	nrsumsize = (uint)sizeof(xfs_suminfo_t) * nrsumlevels * nrbmblocks;
1906 	nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
1907 	nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
1908 	/*
1909 	 * New summary size can't be more than half the size of
1910 	 * the log.  This prevents us from getting a log overflow,
1911 	 * since we'll log basically the whole summary file at once.
1912 	 */
1913 	if (nrsumblocks > (mp->m_sb.sb_logblocks >> 1))
1914 		return XFS_ERROR(EINVAL);
1915 	/*
1916 	 * Get the old block counts for bitmap and summary inodes.
1917 	 * These can't change since other growfs callers are locked out.
1918 	 */
1919 	rbmblocks = XFS_B_TO_FSB(mp, mp->m_rbmip->i_d.di_size);
1920 	rsumblocks = XFS_B_TO_FSB(mp, mp->m_rsumip->i_d.di_size);
1921 	/*
1922 	 * Allocate space to the bitmap and summary files, as necessary.
1923 	 */
1924 	if ((error = xfs_growfs_rt_alloc(mp, rbmblocks, nrbmblocks,
1925 			mp->m_sb.sb_rbmino)))
1926 		return error;
1927 	if ((error = xfs_growfs_rt_alloc(mp, rsumblocks, nrsumblocks,
1928 			mp->m_sb.sb_rsumino)))
1929 		return error;
1930 	/*
1931 	 * Allocate a new (fake) mount/sb.
1932 	 */
1933 	nmp = kmem_alloc(sizeof(*nmp), KM_SLEEP);
1934 	/*
1935 	 * Loop over the bitmap blocks.
1936 	 * We will do everything one bitmap block at a time.
1937 	 * Skip the current block if it is exactly full.
1938 	 * This also deals with the case where there were no rtextents before.
1939 	 */
1940 	for (bmbno = sbp->sb_rbmblocks -
1941 		     ((sbp->sb_rextents & ((1 << mp->m_blkbit_log) - 1)) != 0);
1942 	     bmbno < nrbmblocks;
1943 	     bmbno++) {
1944 		xfs_trans_t	*tp;
1945 		int		cancelflags = 0;
1946 
1947 		*nmp = *mp;
1948 		nsbp = &nmp->m_sb;
1949 		/*
1950 		 * Calculate new sb and mount fields for this round.
1951 		 */
1952 		nsbp->sb_rextsize = in->extsize;
1953 		nsbp->sb_rbmblocks = bmbno + 1;
1954 		nsbp->sb_rblocks =
1955 			XFS_RTMIN(nrblocks,
1956 				  nsbp->sb_rbmblocks * NBBY *
1957 				  nsbp->sb_blocksize * nsbp->sb_rextsize);
1958 		nsbp->sb_rextents = nsbp->sb_rblocks;
1959 		do_div(nsbp->sb_rextents, nsbp->sb_rextsize);
1960 		ASSERT(nsbp->sb_rextents != 0);
1961 		nsbp->sb_rextslog = xfs_highbit32(nsbp->sb_rextents);
1962 		nrsumlevels = nmp->m_rsumlevels = nsbp->sb_rextslog + 1;
1963 		nrsumsize =
1964 			(uint)sizeof(xfs_suminfo_t) * nrsumlevels *
1965 			nsbp->sb_rbmblocks;
1966 		nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);
1967 		nmp->m_rsumsize = nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks);
1968 		/*
1969 		 * Start a transaction, get the log reservation.
1970 		 */
1971 		tp = xfs_trans_alloc(mp, XFS_TRANS_GROWFSRT_FREE);
1972 		if ((error = xfs_trans_reserve(tp, 0,
1973 				XFS_GROWRTFREE_LOG_RES(nmp), 0, 0, 0)))
1974 			goto error_cancel;
1975 		/*
1976 		 * Lock out other callers by grabbing the bitmap inode lock.
1977 		 */
1978 		if ((error = xfs_trans_iget(mp, tp, mp->m_sb.sb_rbmino, 0,
1979 						XFS_ILOCK_EXCL, &ip)))
1980 			goto error_cancel;
1981 		ASSERT(ip == mp->m_rbmip);
1982 		/*
1983 		 * Update the bitmap inode's size.
1984 		 */
1985 		mp->m_rbmip->i_d.di_size =
1986 			nsbp->sb_rbmblocks * nsbp->sb_blocksize;
1987 		xfs_trans_log_inode(tp, mp->m_rbmip, XFS_ILOG_CORE);
1988 		cancelflags |= XFS_TRANS_ABORT;
1989 		/*
1990 		 * Get the summary inode into the transaction.
1991 		 */
1992 		if ((error = xfs_trans_iget(mp, tp, mp->m_sb.sb_rsumino, 0,
1993 						XFS_ILOCK_EXCL, &ip)))
1994 			goto error_cancel;
1995 		ASSERT(ip == mp->m_rsumip);
1996 		/*
1997 		 * Update the summary inode's size.
1998 		 */
1999 		mp->m_rsumip->i_d.di_size = nmp->m_rsumsize;
2000 		xfs_trans_log_inode(tp, mp->m_rsumip, XFS_ILOG_CORE);
2001 		/*
2002 		 * Copy summary data from old to new sizes.
2003 		 * Do this when the real size (not block-aligned) changes.
2004 		 */
2005 		if (sbp->sb_rbmblocks != nsbp->sb_rbmblocks ||
2006 		    mp->m_rsumlevels != nmp->m_rsumlevels) {
2007 			error = xfs_rtcopy_summary(mp, nmp, tp);
2008 			if (error)
2009 				goto error_cancel;
2010 		}
2011 		/*
2012 		 * Update superblock fields.
2013 		 */
2014 		if (nsbp->sb_rextsize != sbp->sb_rextsize)
2015 			xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSIZE,
2016 				nsbp->sb_rextsize - sbp->sb_rextsize);
2017 		if (nsbp->sb_rbmblocks != sbp->sb_rbmblocks)
2018 			xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBMBLOCKS,
2019 				nsbp->sb_rbmblocks - sbp->sb_rbmblocks);
2020 		if (nsbp->sb_rblocks != sbp->sb_rblocks)
2021 			xfs_trans_mod_sb(tp, XFS_TRANS_SB_RBLOCKS,
2022 				nsbp->sb_rblocks - sbp->sb_rblocks);
2023 		if (nsbp->sb_rextents != sbp->sb_rextents)
2024 			xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTENTS,
2025 				nsbp->sb_rextents - sbp->sb_rextents);
2026 		if (nsbp->sb_rextslog != sbp->sb_rextslog)
2027 			xfs_trans_mod_sb(tp, XFS_TRANS_SB_REXTSLOG,
2028 				nsbp->sb_rextslog - sbp->sb_rextslog);
2029 		/*
2030 		 * Free new extent.
2031 		 */
2032 		bp = NULL;
2033 		error = xfs_rtfree_range(nmp, tp, sbp->sb_rextents,
2034 			nsbp->sb_rextents - sbp->sb_rextents, &bp, &sumbno);
2035 		if (error) {
2036 error_cancel:
2037 			xfs_trans_cancel(tp, cancelflags);
2038 			break;
2039 		}
2040 		/*
2041 		 * Mark more blocks free in the superblock.
2042 		 */
2043 		xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS,
2044 			nsbp->sb_rextents - sbp->sb_rextents);
2045 		/*
2046 		 * Update mp values into the real mp structure.
2047 		 */
2048 		mp->m_rsumlevels = nrsumlevels;
2049 		mp->m_rsumsize = nrsumsize;
2050 
2051 		error = xfs_trans_commit(tp, 0);
2052 		if (error)
2053 			break;
2054 	}
2055 
2056 	/*
2057 	 * Free the fake mp structure.
2058 	 */
2059 	kmem_free(nmp);
2060 
2061 	return error;
2062 }
2063 
2064 /*
2065  * Allocate an extent in the realtime subvolume, with the usual allocation
2066  * parameters.  The length units are all in realtime extents, as is the
2067  * result block number.
2068  */
2069 int					/* error */
xfs_rtallocate_extent(xfs_trans_t * tp,xfs_rtblock_t bno,xfs_extlen_t minlen,xfs_extlen_t maxlen,xfs_extlen_t * len,xfs_alloctype_t type,int wasdel,xfs_extlen_t prod,xfs_rtblock_t * rtblock)2070 xfs_rtallocate_extent(
2071 	xfs_trans_t	*tp,		/* transaction pointer */
2072 	xfs_rtblock_t	bno,		/* starting block number to allocate */
2073 	xfs_extlen_t	minlen,		/* minimum length to allocate */
2074 	xfs_extlen_t	maxlen,		/* maximum length to allocate */
2075 	xfs_extlen_t	*len,		/* out: actual length allocated */
2076 	xfs_alloctype_t	type,		/* allocation type XFS_ALLOCTYPE... */
2077 	int		wasdel,		/* was a delayed allocation extent */
2078 	xfs_extlen_t	prod,		/* extent product factor */
2079 	xfs_rtblock_t	*rtblock)	/* out: start block allocated */
2080 {
2081 	int		error;		/* error value */
2082 	xfs_inode_t	*ip;		/* inode for bitmap file */
2083 	xfs_mount_t	*mp;		/* file system mount structure */
2084 	xfs_rtblock_t	r;		/* result allocated block */
2085 	xfs_fsblock_t	sb;		/* summary file block number */
2086 	xfs_buf_t	*sumbp;		/* summary file block buffer */
2087 
2088 	ASSERT(minlen > 0 && minlen <= maxlen);
2089 	mp = tp->t_mountp;
2090 	/*
2091 	 * If prod is set then figure out what to do to minlen and maxlen.
2092 	 */
2093 	if (prod > 1) {
2094 		xfs_extlen_t	i;
2095 
2096 		if ((i = maxlen % prod))
2097 			maxlen -= i;
2098 		if ((i = minlen % prod))
2099 			minlen += prod - i;
2100 		if (maxlen < minlen) {
2101 			*rtblock = NULLRTBLOCK;
2102 			return 0;
2103 		}
2104 	}
2105 	/*
2106 	 * Lock out other callers by grabbing the bitmap inode lock.
2107 	 */
2108 	if ((error = xfs_trans_iget(mp, tp, mp->m_sb.sb_rbmino, 0,
2109 					XFS_ILOCK_EXCL, &ip)))
2110 		return error;
2111 	sumbp = NULL;
2112 	/*
2113 	 * Allocate by size, or near another block, or exactly at some block.
2114 	 */
2115 	switch (type) {
2116 	case XFS_ALLOCTYPE_ANY_AG:
2117 		error = xfs_rtallocate_extent_size(mp, tp, minlen, maxlen, len,
2118 				&sumbp,	&sb, prod, &r);
2119 		break;
2120 	case XFS_ALLOCTYPE_NEAR_BNO:
2121 		error = xfs_rtallocate_extent_near(mp, tp, bno, minlen, maxlen,
2122 				len, &sumbp, &sb, prod, &r);
2123 		break;
2124 	case XFS_ALLOCTYPE_THIS_BNO:
2125 		error = xfs_rtallocate_extent_exact(mp, tp, bno, minlen, maxlen,
2126 				len, &sumbp, &sb, prod, &r);
2127 		break;
2128 	default:
2129 		ASSERT(0);
2130 	}
2131 	if (error) {
2132 		return error;
2133 	}
2134 	/*
2135 	 * If it worked, update the superblock.
2136 	 */
2137 	if (r != NULLRTBLOCK) {
2138 		long	slen = (long)*len;
2139 
2140 		ASSERT(*len >= minlen && *len <= maxlen);
2141 		if (wasdel)
2142 			xfs_trans_mod_sb(tp, XFS_TRANS_SB_RES_FREXTENTS, -slen);
2143 		else
2144 			xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, -slen);
2145 	}
2146 	*rtblock = r;
2147 	return 0;
2148 }
2149 
2150 /*
2151  * Free an extent in the realtime subvolume.  Length is expressed in
2152  * realtime extents, as is the block number.
2153  */
2154 int					/* error */
xfs_rtfree_extent(xfs_trans_t * tp,xfs_rtblock_t bno,xfs_extlen_t len)2155 xfs_rtfree_extent(
2156 	xfs_trans_t	*tp,		/* transaction pointer */
2157 	xfs_rtblock_t	bno,		/* starting block number to free */
2158 	xfs_extlen_t	len)		/* length of extent freed */
2159 {
2160 	int		error;		/* error value */
2161 	xfs_inode_t	*ip;		/* bitmap file inode */
2162 	xfs_mount_t	*mp;		/* file system mount structure */
2163 	xfs_fsblock_t	sb;		/* summary file block number */
2164 	xfs_buf_t	*sumbp;		/* summary file block buffer */
2165 
2166 	mp = tp->t_mountp;
2167 	/*
2168 	 * Synchronize by locking the bitmap inode.
2169 	 */
2170 	if ((error = xfs_trans_iget(mp, tp, mp->m_sb.sb_rbmino, 0,
2171 					XFS_ILOCK_EXCL, &ip)))
2172 		return error;
2173 #if defined(__KERNEL__) && defined(DEBUG)
2174 	/*
2175 	 * Check to see that this whole range is currently allocated.
2176 	 */
2177 	{
2178 		int	stat;		/* result from checking range */
2179 
2180 		error = xfs_rtcheck_alloc_range(mp, tp, bno, len, &stat);
2181 		if (error) {
2182 			return error;
2183 		}
2184 		ASSERT(stat);
2185 	}
2186 #endif
2187 	sumbp = NULL;
2188 	/*
2189 	 * Free the range of realtime blocks.
2190 	 */
2191 	error = xfs_rtfree_range(mp, tp, bno, len, &sumbp, &sb);
2192 	if (error) {
2193 		return error;
2194 	}
2195 	/*
2196 	 * Mark more blocks free in the superblock.
2197 	 */
2198 	xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, (long)len);
2199 	/*
2200 	 * If we've now freed all the blocks, reset the file sequence
2201 	 * number to 0.
2202 	 */
2203 	if (tp->t_frextents_delta + mp->m_sb.sb_frextents ==
2204 	    mp->m_sb.sb_rextents) {
2205 		if (!(ip->i_d.di_flags & XFS_DIFLAG_NEWRTBM))
2206 			ip->i_d.di_flags |= XFS_DIFLAG_NEWRTBM;
2207 		*(__uint64_t *)&ip->i_d.di_atime = 0;
2208 		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
2209 	}
2210 	return 0;
2211 }
2212 
2213 /*
2214  * Initialize realtime fields in the mount structure.
2215  */
2216 int				/* error */
xfs_rtmount_init(xfs_mount_t * mp)2217 xfs_rtmount_init(
2218 	xfs_mount_t	*mp)	/* file system mount structure */
2219 {
2220 	xfs_buf_t	*bp;	/* buffer for last block of subvolume */
2221 	xfs_daddr_t	d;	/* address of last block of subvolume */
2222 	int		error;	/* error return value */
2223 	xfs_sb_t	*sbp;	/* filesystem superblock copy in mount */
2224 
2225 	sbp = &mp->m_sb;
2226 	if (sbp->sb_rblocks == 0)
2227 		return 0;
2228 	if (mp->m_rtdev_targp == NULL) {
2229 		cmn_err(CE_WARN,
2230 	"XFS: This filesystem has a realtime volume, use rtdev=device option");
2231 		return XFS_ERROR(ENODEV);
2232 	}
2233 	mp->m_rsumlevels = sbp->sb_rextslog + 1;
2234 	mp->m_rsumsize =
2235 		(uint)sizeof(xfs_suminfo_t) * mp->m_rsumlevels *
2236 		sbp->sb_rbmblocks;
2237 	mp->m_rsumsize = roundup(mp->m_rsumsize, sbp->sb_blocksize);
2238 	mp->m_rbmip = mp->m_rsumip = NULL;
2239 	/*
2240 	 * Check that the realtime section is an ok size.
2241 	 */
2242 	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_rblocks);
2243 	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_rblocks) {
2244 		cmn_err(CE_WARN, "XFS: realtime mount -- %llu != %llu",
2245 			(unsigned long long) XFS_BB_TO_FSB(mp, d),
2246 			(unsigned long long) mp->m_sb.sb_rblocks);
2247 		return XFS_ERROR(E2BIG);
2248 	}
2249 	error = xfs_read_buf(mp, mp->m_rtdev_targp,
2250 				d - XFS_FSB_TO_BB(mp, 1),
2251 				XFS_FSB_TO_BB(mp, 1), 0, &bp);
2252 	if (error) {
2253 		cmn_err(CE_WARN,
2254 	"XFS: realtime mount -- xfs_read_buf failed, returned %d", error);
2255 		if (error == ENOSPC)
2256 			return XFS_ERROR(E2BIG);
2257 		return error;
2258 	}
2259 	xfs_buf_relse(bp);
2260 	return 0;
2261 }
2262 
2263 /*
2264  * Get the bitmap and summary inodes into the mount structure
2265  * at mount time.
2266  */
2267 int					/* error */
xfs_rtmount_inodes(xfs_mount_t * mp)2268 xfs_rtmount_inodes(
2269 	xfs_mount_t	*mp)		/* file system mount structure */
2270 {
2271 	int		error;		/* error return value */
2272 	xfs_sb_t	*sbp;
2273 
2274 	sbp = &mp->m_sb;
2275 	if (sbp->sb_rbmino == NULLFSINO)
2276 		return 0;
2277 	error = xfs_iget(mp, NULL, sbp->sb_rbmino, 0, 0, &mp->m_rbmip, 0);
2278 	if (error)
2279 		return error;
2280 	ASSERT(mp->m_rbmip != NULL);
2281 	ASSERT(sbp->sb_rsumino != NULLFSINO);
2282 	error = xfs_iget(mp, NULL, sbp->sb_rsumino, 0, 0, &mp->m_rsumip, 0);
2283 	if (error) {
2284 		IRELE(mp->m_rbmip);
2285 		return error;
2286 	}
2287 	ASSERT(mp->m_rsumip != NULL);
2288 	return 0;
2289 }
2290 
2291 /*
2292  * Pick an extent for allocation at the start of a new realtime file.
2293  * Use the sequence number stored in the atime field of the bitmap inode.
2294  * Translate this to a fraction of the rtextents, and return the product
2295  * of rtextents and the fraction.
2296  * The fraction sequence is 0, 1/2, 1/4, 3/4, 1/8, ..., 7/8, 1/16, ...
2297  */
2298 int					/* error */
xfs_rtpick_extent(xfs_mount_t * mp,xfs_trans_t * tp,xfs_extlen_t len,xfs_rtblock_t * pick)2299 xfs_rtpick_extent(
2300 	xfs_mount_t	*mp,		/* file system mount point */
2301 	xfs_trans_t	*tp,		/* transaction pointer */
2302 	xfs_extlen_t	len,		/* allocation length (rtextents) */
2303 	xfs_rtblock_t	*pick)		/* result rt extent */
2304 {
2305 	xfs_rtblock_t	b;		/* result block */
2306 	int		error;		/* error return value */
2307 	xfs_inode_t	*ip;		/* bitmap incore inode */
2308 	int		log2;		/* log of sequence number */
2309 	__uint64_t	resid;		/* residual after log removed */
2310 	__uint64_t	seq;		/* sequence number of file creation */
2311 	__uint64_t	*seqp;		/* pointer to seqno in inode */
2312 
2313 	if ((error = xfs_trans_iget(mp, tp, mp->m_sb.sb_rbmino, 0,
2314 					XFS_ILOCK_EXCL, &ip)))
2315 		return error;
2316 	ASSERT(ip == mp->m_rbmip);
2317 	seqp = (__uint64_t *)&ip->i_d.di_atime;
2318 	if (!(ip->i_d.di_flags & XFS_DIFLAG_NEWRTBM)) {
2319 		ip->i_d.di_flags |= XFS_DIFLAG_NEWRTBM;
2320 		*seqp = 0;
2321 	}
2322 	seq = *seqp;
2323 	if ((log2 = xfs_highbit64(seq)) == -1)
2324 		b = 0;
2325 	else {
2326 		resid = seq - (1ULL << log2);
2327 		b = (mp->m_sb.sb_rextents * ((resid << 1) + 1ULL)) >>
2328 		    (log2 + 1);
2329 		if (b >= mp->m_sb.sb_rextents)
2330 			b = do_mod(b, mp->m_sb.sb_rextents);
2331 		if (b + len > mp->m_sb.sb_rextents)
2332 			b = mp->m_sb.sb_rextents - len;
2333 	}
2334 	*seqp = seq + 1;
2335 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
2336 	*pick = b;
2337 	return 0;
2338 }
2339