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[thirdparty/xfsprogs-dev.git] / libxfs / xfs_rtalloc.c
1 /*
2 * Copyright (c) 2000-2002,2005 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
19 /*
20 * Free realtime space allocation for XFS.
21 */
22
23 #include <xfs.h>
24
25 extern int xfs_lowbit32(__uint32_t);
26
27 /*
28 * Get a buffer for the bitmap or summary file block specified.
29 * The buffer is returned read and locked.
30 */
31 STATIC int /* error */
32 xfs_rtbuf_get(
33 xfs_mount_t *mp, /* file system mount structure */
34 xfs_trans_t *tp, /* transaction pointer */
35 xfs_rtblock_t block, /* block number in bitmap or summary */
36 int issum, /* is summary not bitmap */
37 xfs_buf_t **bpp) /* output: buffer for the block */
38 {
39 xfs_buf_t *bp; /* block buffer, result */
40 xfs_daddr_t d; /* disk addr of block */
41 int error; /* error value */
42 xfs_fsblock_t fsb; /* fs block number for block */
43 xfs_inode_t *ip; /* bitmap or summary inode */
44
45 ip = issum ? mp->m_rsumip : mp->m_rbmip;
46 /*
47 * Map from the file offset (block) and inode number to the
48 * file system block.
49 */
50 error = xfs_bmapi_single(tp, ip, XFS_DATA_FORK, &fsb, block);
51 if (error) {
52 return error;
53 }
54 ASSERT(fsb != NULLFSBLOCK);
55 /*
56 * Convert to disk address for buffer cache.
57 */
58 d = XFS_FSB_TO_DADDR(mp, fsb);
59 /*
60 * Read the buffer.
61 */
62 error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
63 mp->m_bsize, 0, &bp);
64 if (error) {
65 return error;
66 }
67 ASSERT(bp && !XFS_BUF_GETERROR(bp));
68 *bpp = bp;
69 return 0;
70 }
71
72 /*
73 * Searching backward from start to limit, find the first block whose
74 * allocated/free state is different from start's.
75 */
76 STATIC int /* error */
77 xfs_rtfind_back(
78 xfs_mount_t *mp, /* file system mount point */
79 xfs_trans_t *tp, /* transaction pointer */
80 xfs_rtblock_t start, /* starting block to look at */
81 xfs_rtblock_t limit, /* last block to look at */
82 xfs_rtblock_t *rtblock) /* out: start block found */
83 {
84 xfs_rtword_t *b; /* current word in buffer */
85 int bit; /* bit number in the word */
86 xfs_rtblock_t block; /* bitmap block number */
87 xfs_buf_t *bp; /* buf for the block */
88 xfs_rtword_t *bufp; /* starting word in buffer */
89 int error; /* error value */
90 xfs_rtblock_t firstbit; /* first useful bit in the word */
91 xfs_rtblock_t i; /* current bit number rel. to start */
92 xfs_rtblock_t len; /* length of inspected area */
93 xfs_rtword_t mask; /* mask of relevant bits for value */
94 xfs_rtword_t want; /* mask for "good" values */
95 xfs_rtword_t wdiff; /* difference from wanted value */
96 int word; /* word number in the buffer */
97
98 /*
99 * Compute and read in starting bitmap block for starting block.
100 */
101 block = XFS_BITTOBLOCK(mp, start);
102 error = xfs_rtbuf_get(mp, tp, block, 0, &bp);
103 if (error) {
104 return error;
105 }
106 bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
107 /*
108 * Get the first word's index & point to it.
109 */
110 word = XFS_BITTOWORD(mp, start);
111 b = &bufp[word];
112 bit = (int)(start & (XFS_NBWORD - 1));
113 len = start - limit + 1;
114 /*
115 * Compute match value, based on the bit at start: if 1 (free)
116 * then all-ones, else all-zeroes.
117 */
118 want = (*b & ((xfs_rtword_t)1 << bit)) ? -1 : 0;
119 /*
120 * If the starting position is not word-aligned, deal with the
121 * partial word.
122 */
123 if (bit < XFS_NBWORD - 1) {
124 /*
125 * Calculate first (leftmost) bit number to look at,
126 * and mask for all the relevant bits in this word.
127 */
128 firstbit = XFS_RTMAX((xfs_srtblock_t)(bit - len + 1), 0);
129 mask = (((xfs_rtword_t)1 << (bit - firstbit + 1)) - 1) <<
130 firstbit;
131 /*
132 * Calculate the difference between the value there
133 * and what we're looking for.
134 */
135 if ((wdiff = (*b ^ want) & mask)) {
136 /*
137 * Different. Mark where we are and return.
138 */
139 xfs_trans_brelse(tp, bp);
140 i = bit - XFS_RTHIBIT(wdiff);
141 *rtblock = start - i + 1;
142 return 0;
143 }
144 i = bit - firstbit + 1;
145 /*
146 * Go on to previous block if that's where the previous word is
147 * and we need the previous word.
148 */
149 if (--word == -1 && i < len) {
150 /*
151 * If done with this block, get the previous one.
152 */
153 xfs_trans_brelse(tp, bp);
154 error = xfs_rtbuf_get(mp, tp, --block, 0, &bp);
155 if (error) {
156 return error;
157 }
158 bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
159 word = XFS_BLOCKWMASK(mp);
160 b = &bufp[word];
161 } else {
162 /*
163 * Go on to the previous word in the buffer.
164 */
165 b--;
166 }
167 } else {
168 /*
169 * Starting on a word boundary, no partial word.
170 */
171 i = 0;
172 }
173 /*
174 * Loop over whole words in buffers. When we use up one buffer
175 * we move on to the previous one.
176 */
177 while (len - i >= XFS_NBWORD) {
178 /*
179 * Compute difference between actual and desired value.
180 */
181 if ((wdiff = *b ^ want)) {
182 /*
183 * Different, mark where we are and return.
184 */
185 xfs_trans_brelse(tp, bp);
186 i += XFS_NBWORD - 1 - XFS_RTHIBIT(wdiff);
187 *rtblock = start - i + 1;
188 return 0;
189 }
190 i += XFS_NBWORD;
191 /*
192 * Go on to previous block if that's where the previous word is
193 * and we need the previous word.
194 */
195 if (--word == -1 && i < len) {
196 /*
197 * If done with this block, get the previous one.
198 */
199 xfs_trans_brelse(tp, bp);
200 error = xfs_rtbuf_get(mp, tp, --block, 0, &bp);
201 if (error) {
202 return error;
203 }
204 bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
205 word = XFS_BLOCKWMASK(mp);
206 b = &bufp[word];
207 } else {
208 /*
209 * Go on to the previous word in the buffer.
210 */
211 b--;
212 }
213 }
214 /*
215 * If not ending on a word boundary, deal with the last
216 * (partial) word.
217 */
218 if (len - i) {
219 /*
220 * Calculate first (leftmost) bit number to look at,
221 * and mask for all the relevant bits in this word.
222 */
223 firstbit = XFS_NBWORD - (len - i);
224 mask = (((xfs_rtword_t)1 << (len - i)) - 1) << firstbit;
225 /*
226 * Compute difference between actual and desired value.
227 */
228 if ((wdiff = (*b ^ want) & mask)) {
229 /*
230 * Different, mark where we are and return.
231 */
232 xfs_trans_brelse(tp, bp);
233 i += XFS_NBWORD - 1 - XFS_RTHIBIT(wdiff);
234 *rtblock = start - i + 1;
235 return 0;
236 } else
237 i = len;
238 }
239 /*
240 * No match, return that we scanned the whole area.
241 */
242 xfs_trans_brelse(tp, bp);
243 *rtblock = start - i + 1;
244 return 0;
245 }
246
247 /*
248 * Searching forward from start to limit, find the first block whose
249 * allocated/free state is different from start's.
250 */
251 STATIC int /* error */
252 xfs_rtfind_forw(
253 xfs_mount_t *mp, /* file system mount point */
254 xfs_trans_t *tp, /* transaction pointer */
255 xfs_rtblock_t start, /* starting block to look at */
256 xfs_rtblock_t limit, /* last block to look at */
257 xfs_rtblock_t *rtblock) /* out: start block found */
258 {
259 xfs_rtword_t *b; /* current word in buffer */
260 int bit; /* bit number in the word */
261 xfs_rtblock_t block; /* bitmap block number */
262 xfs_buf_t *bp; /* buf for the block */
263 xfs_rtword_t *bufp; /* starting word in buffer */
264 int error; /* error value */
265 xfs_rtblock_t i; /* current bit number rel. to start */
266 xfs_rtblock_t lastbit; /* last useful bit in the word */
267 xfs_rtblock_t len; /* length of inspected area */
268 xfs_rtword_t mask; /* mask of relevant bits for value */
269 xfs_rtword_t want; /* mask for "good" values */
270 xfs_rtword_t wdiff; /* difference from wanted value */
271 int word; /* word number in the buffer */
272
273 /*
274 * Compute and read in starting bitmap block for starting block.
275 */
276 block = XFS_BITTOBLOCK(mp, start);
277 error = xfs_rtbuf_get(mp, tp, block, 0, &bp);
278 if (error) {
279 return error;
280 }
281 bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
282 /*
283 * Get the first word's index & point to it.
284 */
285 word = XFS_BITTOWORD(mp, start);
286 b = &bufp[word];
287 bit = (int)(start & (XFS_NBWORD - 1));
288 len = limit - start + 1;
289 /*
290 * Compute match value, based on the bit at start: if 1 (free)
291 * then all-ones, else all-zeroes.
292 */
293 want = (*b & ((xfs_rtword_t)1 << bit)) ? -1 : 0;
294 /*
295 * If the starting position is not word-aligned, deal with the
296 * partial word.
297 */
298 if (bit) {
299 /*
300 * Calculate last (rightmost) bit number to look at,
301 * and mask for all the relevant bits in this word.
302 */
303 lastbit = XFS_RTMIN(bit + len, XFS_NBWORD);
304 mask = (((xfs_rtword_t)1 << (lastbit - bit)) - 1) << bit;
305 /*
306 * Calculate the difference between the value there
307 * and what we're looking for.
308 */
309 if ((wdiff = (*b ^ want) & mask)) {
310 /*
311 * Different. Mark where we are and return.
312 */
313 xfs_trans_brelse(tp, bp);
314 i = XFS_RTLOBIT(wdiff) - bit;
315 *rtblock = start + i - 1;
316 return 0;
317 }
318 i = lastbit - bit;
319 /*
320 * Go on to next block if that's where the next word is
321 * and we need the next word.
322 */
323 if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
324 /*
325 * If done with this block, get the previous one.
326 */
327 xfs_trans_brelse(tp, bp);
328 error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
329 if (error) {
330 return error;
331 }
332 b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
333 word = 0;
334 } else {
335 /*
336 * Go on to the previous word in the buffer.
337 */
338 b++;
339 }
340 } else {
341 /*
342 * Starting on a word boundary, no partial word.
343 */
344 i = 0;
345 }
346 /*
347 * Loop over whole words in buffers. When we use up one buffer
348 * we move on to the next one.
349 */
350 while (len - i >= XFS_NBWORD) {
351 /*
352 * Compute difference between actual and desired value.
353 */
354 if ((wdiff = *b ^ want)) {
355 /*
356 * Different, mark where we are and return.
357 */
358 xfs_trans_brelse(tp, bp);
359 i += XFS_RTLOBIT(wdiff);
360 *rtblock = start + i - 1;
361 return 0;
362 }
363 i += XFS_NBWORD;
364 /*
365 * Go on to next block if that's where the next word is
366 * and we need the next word.
367 */
368 if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
369 /*
370 * If done with this block, get the next one.
371 */
372 xfs_trans_brelse(tp, bp);
373 error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
374 if (error) {
375 return error;
376 }
377 b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
378 word = 0;
379 } else {
380 /*
381 * Go on to the next word in the buffer.
382 */
383 b++;
384 }
385 }
386 /*
387 * If not ending on a word boundary, deal with the last
388 * (partial) word.
389 */
390 if ((lastbit = len - i)) {
391 /*
392 * Calculate mask for all the relevant bits in this word.
393 */
394 mask = ((xfs_rtword_t)1 << lastbit) - 1;
395 /*
396 * Compute difference between actual and desired value.
397 */
398 if ((wdiff = (*b ^ want) & mask)) {
399 /*
400 * Different, mark where we are and return.
401 */
402 xfs_trans_brelse(tp, bp);
403 i += XFS_RTLOBIT(wdiff);
404 *rtblock = start + i - 1;
405 return 0;
406 } else
407 i = len;
408 }
409 /*
410 * No match, return that we scanned the whole area.
411 */
412 xfs_trans_brelse(tp, bp);
413 *rtblock = start + i - 1;
414 return 0;
415 }
416
417 /*
418 * Mark an extent specified by start and len freed.
419 * Updates all the summary information as well as the bitmap.
420 */
421 STATIC int /* error */
422 xfs_rtfree_range(
423 xfs_mount_t *mp, /* file system mount point */
424 xfs_trans_t *tp, /* transaction pointer */
425 xfs_rtblock_t start, /* starting block to free */
426 xfs_extlen_t len, /* length to free */
427 xfs_buf_t **rbpp, /* in/out: summary block buffer */
428 xfs_fsblock_t *rsb) /* in/out: summary block number */
429 {
430 xfs_rtblock_t end; /* end of the freed extent */
431 int error; /* error value */
432 xfs_rtblock_t postblock; /* first block freed > end */
433 xfs_rtblock_t preblock; /* first block freed < start */
434
435 end = start + len - 1;
436 /*
437 * Modify the bitmap to mark this extent freed.
438 */
439 error = xfs_rtmodify_range(mp, tp, start, len, 1);
440 if (error) {
441 return error;
442 }
443 /*
444 * Assume we're freeing out of the middle of an allocated extent.
445 * We need to find the beginning and end of the extent so we can
446 * properly update the summary.
447 */
448 error = xfs_rtfind_back(mp, tp, start, 0, &preblock);
449 if (error) {
450 return error;
451 }
452 /*
453 * Find the next allocated block (end of allocated extent).
454 */
455 error = xfs_rtfind_forw(mp, tp, end, mp->m_sb.sb_rextents - 1,
456 &postblock);
457 /*
458 * If there are blocks not being freed at the front of the
459 * old extent, add summary data for them to be allocated.
460 */
461 if (preblock < start) {
462 error = xfs_rtmodify_summary(mp, tp,
463 XFS_RTBLOCKLOG(start - preblock),
464 XFS_BITTOBLOCK(mp, preblock), -1, rbpp, rsb);
465 if (error) {
466 return error;
467 }
468 }
469 /*
470 * If there are blocks not being freed at the end of the
471 * old extent, add summary data for them to be allocated.
472 */
473 if (postblock > end) {
474 error = xfs_rtmodify_summary(mp, tp,
475 XFS_RTBLOCKLOG(postblock - end),
476 XFS_BITTOBLOCK(mp, end + 1), -1, rbpp, rsb);
477 if (error) {
478 return error;
479 }
480 }
481 /*
482 * Increment the summary information corresponding to the entire
483 * (new) free extent.
484 */
485 error = xfs_rtmodify_summary(mp, tp,
486 XFS_RTBLOCKLOG(postblock + 1 - preblock),
487 XFS_BITTOBLOCK(mp, preblock), 1, rbpp, rsb);
488 return error;
489 }
490
491 /*
492 * Set the given range of bitmap bits to the given value.
493 * Do whatever I/O and logging is required.
494 */
495 STATIC int /* error */
496 xfs_rtmodify_range(
497 xfs_mount_t *mp, /* file system mount point */
498 xfs_trans_t *tp, /* transaction pointer */
499 xfs_rtblock_t start, /* starting block to modify */
500 xfs_extlen_t len, /* length of extent to modify */
501 int val) /* 1 for free, 0 for allocated */
502 {
503 xfs_rtword_t *b; /* current word in buffer */
504 int bit; /* bit number in the word */
505 xfs_rtblock_t block; /* bitmap block number */
506 xfs_buf_t *bp; /* buf for the block */
507 xfs_rtword_t *bufp; /* starting word in buffer */
508 int error; /* error value */
509 xfs_rtword_t *first; /* first used word in the buffer */
510 int i; /* current bit number rel. to start */
511 int lastbit; /* last useful bit in word */
512 xfs_rtword_t mask; /* mask o frelevant bits for value */
513 int word; /* word number in the buffer */
514
515 /*
516 * Compute starting bitmap block number.
517 */
518 block = XFS_BITTOBLOCK(mp, start);
519 /*
520 * Read the bitmap block, and point to its data.
521 */
522 error = xfs_rtbuf_get(mp, tp, block, 0, &bp);
523 if (error) {
524 return error;
525 }
526 bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
527 /*
528 * Compute the starting word's address, and starting bit.
529 */
530 word = XFS_BITTOWORD(mp, start);
531 first = b = &bufp[word];
532 bit = (int)(start & (XFS_NBWORD - 1));
533 /*
534 * 0 (allocated) => all zeroes; 1 (free) => all ones.
535 */
536 val = -val;
537 /*
538 * If not starting on a word boundary, deal with the first
539 * (partial) word.
540 */
541 if (bit) {
542 /*
543 * Compute first bit not changed and mask of relevant bits.
544 */
545 lastbit = XFS_RTMIN(bit + len, XFS_NBWORD);
546 mask = (((xfs_rtword_t)1 << (lastbit - bit)) - 1) << bit;
547 /*
548 * Set/clear the active bits.
549 */
550 if (val)
551 *b |= mask;
552 else
553 *b &= ~mask;
554 i = lastbit - bit;
555 /*
556 * Go on to the next block if that's where the next word is
557 * and we need the next word.
558 */
559 if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
560 /*
561 * Log the changed part of this block.
562 * Get the next one.
563 */
564 xfs_trans_log_buf(tp, bp,
565 (uint)((char *)first - (char *)bufp),
566 (uint)((char *)b - (char *)bufp));
567 error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
568 if (error) {
569 return error;
570 }
571 first = b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
572 word = 0;
573 } else {
574 /*
575 * Go on to the next word in the buffer
576 */
577 b++;
578 }
579 } else {
580 /*
581 * Starting on a word boundary, no partial word.
582 */
583 i = 0;
584 }
585 /*
586 * Loop over whole words in buffers. When we use up one buffer
587 * we move on to the next one.
588 */
589 while (len - i >= XFS_NBWORD) {
590 /*
591 * Set the word value correctly.
592 */
593 *b = val;
594 i += XFS_NBWORD;
595 /*
596 * Go on to the next block if that's where the next word is
597 * and we need the next word.
598 */
599 if (++word == XFS_BLOCKWSIZE(mp) && i < len) {
600 /*
601 * Log the changed part of this block.
602 * Get the next one.
603 */
604 xfs_trans_log_buf(tp, bp,
605 (uint)((char *)first - (char *)bufp),
606 (uint)((char *)b - (char *)bufp));
607 error = xfs_rtbuf_get(mp, tp, ++block, 0, &bp);
608 if (error) {
609 return error;
610 }
611 first = b = bufp = (xfs_rtword_t *)XFS_BUF_PTR(bp);
612 word = 0;
613 } else {
614 /*
615 * Go on to the next word in the buffer
616 */
617 b++;
618 }
619 }
620 /*
621 * If not ending on a word boundary, deal with the last
622 * (partial) word.
623 */
624 if ((lastbit = len - i)) {
625 /*
626 * Compute a mask of relevant bits.
627 */
628 bit = 0;
629 mask = ((xfs_rtword_t)1 << lastbit) - 1;
630 /*
631 * Set/clear the active bits.
632 */
633 if (val)
634 *b |= mask;
635 else
636 *b &= ~mask;
637 b++;
638 }
639 /*
640 * Log any remaining changed bytes.
641 */
642 if (b > first)
643 xfs_trans_log_buf(tp, bp, (uint)((char *)first - (char *)bufp),
644 (uint)((char *)b - (char *)bufp - 1));
645 return 0;
646 }
647
648 /*
649 * Read and modify the summary information for a given extent size,
650 * bitmap block combination.
651 * Keeps track of a current summary block, so we don't keep reading
652 * it from the buffer cache.
653 */
654 STATIC int /* error */
655 xfs_rtmodify_summary(
656 xfs_mount_t *mp, /* file system mount point */
657 xfs_trans_t *tp, /* transaction pointer */
658 int log, /* log2 of extent size */
659 xfs_rtblock_t bbno, /* bitmap block number */
660 int delta, /* change to make to summary info */
661 xfs_buf_t **rbpp, /* in/out: summary block buffer */
662 xfs_fsblock_t *rsb) /* in/out: summary block number */
663 {
664 xfs_buf_t *bp; /* buffer for the summary block */
665 int error; /* error value */
666 xfs_fsblock_t sb; /* summary fsblock */
667 int so; /* index into the summary file */
668 xfs_suminfo_t *sp; /* pointer to returned data */
669
670 /*
671 * Compute entry number in the summary file.
672 */
673 so = XFS_SUMOFFS(mp, log, bbno);
674 /*
675 * Compute the block number in the summary file.
676 */
677 sb = XFS_SUMOFFSTOBLOCK(mp, so);
678 /*
679 * If we have an old buffer, and the block number matches, use that.
680 */
681 if (rbpp && *rbpp && *rsb == sb)
682 bp = *rbpp;
683 /*
684 * Otherwise we have to get the buffer.
685 */
686 else {
687 /*
688 * If there was an old one, get rid of it first.
689 */
690 if (rbpp && *rbpp)
691 xfs_trans_brelse(tp, *rbpp);
692 error = xfs_rtbuf_get(mp, tp, sb, 1, &bp);
693 if (error) {
694 return error;
695 }
696 /*
697 * Remember this buffer and block for the next call.
698 */
699 if (rbpp) {
700 *rbpp = bp;
701 *rsb = sb;
702 }
703 }
704 /*
705 * Point to the summary information, modify and log it.
706 */
707 sp = XFS_SUMPTR(mp, bp, so);
708 *sp += delta;
709 xfs_trans_log_buf(tp, bp, (uint)((char *)sp - (char *)XFS_BUF_PTR(bp)),
710 (uint)((char *)sp - (char *)XFS_BUF_PTR(bp) + sizeof(*sp) - 1));
711 return 0;
712 }
713
714 /*
715 * Free an extent in the realtime subvolume. Length is expressed in
716 * realtime extents, as is the block number.
717 */
718 int /* error */
719 xfs_rtfree_extent(
720 xfs_trans_t *tp, /* transaction pointer */
721 xfs_rtblock_t bno, /* starting block number to free */
722 xfs_extlen_t len) /* length of extent freed */
723 {
724 int error; /* error value */
725 xfs_inode_t *ip; /* bitmap file inode */
726 xfs_mount_t *mp; /* file system mount structure */
727 xfs_fsblock_t sb; /* summary file block number */
728 xfs_buf_t *sumbp; /* summary file block buffer */
729
730 mp = tp->t_mountp;
731 /*
732 * Synchronize by locking the bitmap inode.
733 */
734 error = xfs_trans_iget(mp, tp, mp->m_sb.sb_rbmino, 0, XFS_ILOCK_EXCL, &ip);
735 if (error) {
736 return error;
737 }
738 #if defined(__KERNEL__) && defined(DEBUG)
739 /*
740 * Check to see that this whole range is currently allocated.
741 */
742 {
743 int stat; /* result from checking range */
744
745 error = xfs_rtcheck_alloc_range(mp, tp, bno, len, &stat);
746 if (error) {
747 return error;
748 }
749 ASSERT(stat);
750 }
751 #endif
752 sumbp = NULL;
753 /*
754 * Free the range of realtime blocks.
755 */
756 error = xfs_rtfree_range(mp, tp, bno, len, &sumbp, &sb);
757 if (error) {
758 return error;
759 }
760 /*
761 * Mark more blocks free in the superblock.
762 */
763 xfs_trans_mod_sb(tp, XFS_TRANS_SB_FREXTENTS, (long)len);
764 /*
765 * If we've now freed all the blocks, reset the file sequence
766 * number to 0.
767 */
768 if (tp->t_frextents_delta + mp->m_sb.sb_frextents ==
769 mp->m_sb.sb_rextents) {
770 if (!(ip->i_d.di_flags & XFS_DIFLAG_NEWRTBM))
771 ip->i_d.di_flags |= XFS_DIFLAG_NEWRTBM;
772 *(__uint64_t *)&ip->i_d.di_atime = 0;
773 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
774 }
775 return 0;
776 }
777
778 /*
779 * Pick an extent for allocation at the start of a new realtime file.
780 * Use the sequence number stored in the atime field of the bitmap inode.
781 * Translate this to a fraction of the rtextents, and return the product
782 * of rtextents and the fraction.
783 * The fraction sequence is 0, 1/2, 1/4, 3/4, 1/8, ..., 7/8, 1/16, ...
784 */
785 int /* error */
786 xfs_rtpick_extent(
787 xfs_mount_t *mp, /* file system mount point */
788 xfs_trans_t *tp, /* transaction pointer */
789 xfs_extlen_t len, /* allocation length (rtextents) */
790 xfs_rtblock_t *pick) /* result rt extent */
791 {
792 xfs_rtblock_t b; /* result block */
793 int error; /* error return value */
794 xfs_inode_t *ip; /* bitmap incore inode */
795 int log2; /* log of sequence number */
796 __uint64_t resid; /* residual after log removed */
797 __uint64_t seq; /* sequence number of file creation */
798 __uint64_t *seqp; /* pointer to seqno in inode */
799
800 error = xfs_trans_iget(mp, tp, mp->m_sb.sb_rbmino, 0, XFS_ILOCK_EXCL, &ip);
801 if (error)
802 return error;
803 ASSERT(ip == mp->m_rbmip);
804 seqp = (__uint64_t *)&ip->i_d.di_atime;
805 if (!(ip->i_d.di_flags & XFS_DIFLAG_NEWRTBM)) {
806 ip->i_d.di_flags |= XFS_DIFLAG_NEWRTBM;
807 *seqp = 0;
808 }
809 seq = *seqp;
810 if ((log2 = xfs_highbit64(seq)) == -1)
811 b = 0;
812 else {
813 resid = seq - (1ULL << log2);
814 b = (mp->m_sb.sb_rextents * ((resid << 1) + 1ULL)) >>
815 (log2 + 1);
816 if (b >= mp->m_sb.sb_rextents)
817 b = do_mod(b, mp->m_sb.sb_rextents);
818 if (b + len > mp->m_sb.sb_rextents)
819 b = mp->m_sb.sb_rextents - len;
820 }
821 *seqp = seq + 1;
822 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
823 *pick = b;
824 return 0;
825 }
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