| blob | 92d4331cd4f1c118ea0a0087849d399a3948f230 |
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 */
43 /*
44 * Prototypes for internal functions.
45 */
65 /*
66 * Internal functions.
67 */
69 /*
70 * Allocate space to the bitmap or summary file, and zero it, for growfs.
71 */
78 {
91 /*
92 * Allocate space to the file, as necessary.
93 */
100 /*
101 * Reserve space & log for one extent added to the file.
102 */
105 XFS_TRANS_PERM_LOG_RES,
106 XFS_DEFAULT_PERM_LOG_COUNT)))
109 /*
110 * Lock the inode.
111 */
116 /*
117 * Allocate blocks to the bitmap file.
118 */
128 /*
129 * Free any blocks freed up in the transaction, then commit.
130 */
137 /*
138 * Now we need to clear the allocated blocks.
139 * Do this one block per transaction, to keep it simple.
140 */
146 /*
147 * Reserve log for one block zeroing.
148 */
152 /*
153 * Lock the bitmap inode.
154 */
157 /*
158 * Get a buffer for the block.
159 */
165 error_cancel:
168 }
171 /*
172 * Commit the transaction.
173 */
177 }
178 /*
179 * Go on to the next extent, if any.
180 */
182 }
185 error:
187 }
189 /*
190 * Attempt to allocate an extent minlen<=len<=maxlen starting from
191 * bitmap block bbno. If we don't get maxlen then use prod to trim
192 * the length, if given. Returns error; returns starting block in *rtblock.
193 * The lengths are all in rtextents.
194 */
208 {
217 /*
218 * Loop over all the extents starting in this bitmap block,
219 * looking for one that's long enough.
220 */
224 i++) {
225 /*
226 * See if there's a free extent of maxlen starting at i.
227 * If it's not so then next will contain the first non-free.
228 */
232 }
234 /*
235 * i for maxlen is all free, allocate and return that.
236 */
238 rsb);
241 }
245 }
246 /*
247 * In the case where we have a variable-sized allocation
248 * request, figure out how big this free piece is,
249 * and if it's big enough for the minimum, and the best
250 * so far, remember it.
251 */
259 }
260 }
261 /*
262 * If not done yet, find the start of the next free space.
263 */
268 }
271 }
272 /*
273 * Searched the whole thing & didn't find a maxlen free extent.
274 */
278 /*
279 * If size should be a multiple of prod, make that so.
280 */
283 /*
284 * Allocate besti for bestlen & return that.
285 */
289 }
293 }
294 /*
295 * Allocation failed. Set *nextp to the next block to try.
296 */
300 }
302 /*
303 * Allocate an extent of length minlen<=len<=maxlen, starting at block
304 * bno. If we don't get maxlen then use prod to trim the length, if given.
305 * Returns error; returns starting block in *rtblock.
306 * The lengths are all in rtextents.
307 */
320 {
327 /*
328 * Check if the range in question (for maxlen) is free.
329 */
333 }
335 /*
336 * If it is, allocate it and return success.
337 */
341 }
345 }
346 /*
347 * If not, allocate what there is, if it's at least minlen.
348 */
351 /*
352 * Failed, return failure status.
353 */
356 }
357 /*
358 * Trim off tail of extent, if prod is specified.
359 */
363 /*
364 * Now we can't do it, return failure status.
365 */
368 }
369 }
370 /*
371 * Allocate what we can and return it.
372 */
376 }
380 }
382 /*
383 * Allocate an extent of length minlen<=len<=maxlen, starting as near
384 * to bno as possible. If we don't get maxlen then use prod to trim
385 * the length, if given. The lengths are all in rtextents.
386 */
399 {
410 /*
411 * If the block number given is off the end, silently set it to
412 * the last block.
413 */
416 /*
417 * Try the exact allocation first.
418 */
423 }
424 /*
425 * If the exact allocation worked, return that.
426 */
430 }
435 /*
436 * Loop over all bitmap blocks (bbno + i is current block).
437 */
439 /*
440 * Get summary information of extents of all useful levels
441 * starting in this bitmap block.
442 */
447 }
448 /*
449 * If there are any useful extents starting here, try
450 * allocating one.
451 */
453 /*
454 * On the positive side of the starting location.
455 */
457 /*
458 * Try to allocate an extent starting in
459 * this block.
460 */
466 }
467 /*
468 * If it worked, return it.
469 */
473 }
474 }
475 /*
476 * On the negative side of the starting location.
477 */
479 /*
480 * Loop backwards through the bitmap blocks from
481 * the starting point-1 up to where we are now.
482 * There should be an extent which ends in this
483 * bitmap block and is long enough.
484 */
486 /*
487 * Grab the summary information for
488 * this bitmap block.
489 */
495 }
496 /*
497 * If there's no extent given in the
498 * summary that means the extent we
499 * found must carry over from an
500 * earlier block. If there is an
501 * extent given, we've already tried
502 * that allocation, don't do it again.
503 */
511 }
512 /*
513 * If it works, return the extent.
514 */
518 }
519 }
520 /*
521 * There weren't intervening bitmap blocks
522 * with a long enough extent, or the
523 * allocation didn't work for some reason
524 * (i.e. it's a little * too short).
525 * Try to allocate from the summary block
526 * that we found.
527 */
533 }
534 /*
535 * If it works, return the extent.
536 */
540 }
541 }
542 }
543 /*
544 * Loop control. If we were on the positive side, and there's
545 * still more blocks on the negative side, go there.
546 */
549 /*
550 * If positive, and no more negative, but there are more
551 * positive, go there.
552 */
554 i++;
555 /*
556 * If negative or 0 (just started), and there are positive
557 * blocks to go, go there. The 0 case moves to block 1.
558 */
561 /*
562 * If negative or 0 and there are more negative blocks,
563 * go there.
564 */
566 i--;
567 /*
568 * Must be done. Return failure.
569 */
570 else
572 }
575 }
577 /*
578 * Allocate an extent of length minlen<=len<=maxlen, with no position
579 * specified. If we don't get maxlen then use prod to trim
580 * the length, if given. The lengths are all in rtextents.
581 */
593 {
604 /*
605 * Loop over all the levels starting with maxlen.
606 * At each level, look at all the bitmap blocks, to see if there
607 * are extents starting there that are long enough (>= maxlen).
608 * Note, only on the initial level can the allocation fail if
609 * the summary says there's an extent.
610 */
612 /*
613 * Loop over all the bitmap blocks.
614 */
616 /*
617 * Get the summary for this level/block.
618 */
623 }
624 /*
625 * Nothing there, on to the next block.
626 */
629 /*
630 * Try allocating the extent.
631 */
636 }
637 /*
638 * If it worked, return that.
639 */
643 }
644 /*
645 * If the "next block to try" returned from the
646 * allocator is beyond the next bitmap block,
647 * skip to that bitmap block.
648 */
651 }
652 }
653 /*
654 * Didn't find any maxlen blocks. Try smaller ones, unless
655 * we're asking for a fixed size extent.
656 */
660 }
664 /*
665 * Loop over sizes, from maxlen down to minlen.
666 * This time, when we do the allocations, allow smaller ones
667 * to succeed.
668 */
670 /*
671 * Loop over all the bitmap blocks, try an allocation
672 * starting in that block.
673 */
675 /*
676 * Get the summary information for this level/block.
677 */
682 }
683 /*
684 * If nothing there, go on to next.
685 */
688 /*
689 * Try the allocation. Make sure the specified
690 * minlen/maxlen are in the possible range for
691 * this summary level.
692 */
699 }
700 /*
701 * If it worked, return that extent.
702 */
706 }
707 /*
708 * If the "next block to try" returned from the
709 * allocator is beyond the next bitmap block,
710 * skip to that bitmap block.
711 */
714 }
715 }
716 /*
717 * Got nothing, return failure.
718 */
721 }
723 /*
724 * Mark an extent specified by start and len allocated.
725 * Updates all the summary information as well as the bitmap.
726 */
735 {
742 /*
743 * Assume we're allocating out of the middle of a free extent.
744 * We need to find the beginning and end of the extent so we can
745 * properly update the summary.
746 */
750 }
751 /*
752 * Find the next allocated block (end of free extent).
753 */
758 }
759 /*
760 * Decrement the summary information corresponding to the entire
761 * (old) free extent.
762 */
768 }
769 /*
770 * If there are blocks not being allocated at the front of the
771 * old extent, add summary data for them to be free.
772 */
779 }
780 }
781 /*
782 * If there are blocks not being allocated at the end of the
783 * old extent, add summary data for them to be free.
784 */
791 }
792 }
793 /*
794 * Modify the bitmap to mark this extent allocated.
795 */
798 }
800 /*
801 * Return whether there are any free extents in the size range given
802 * by low and high, for the bitmap block bbno.
803 */
814 {
819 /*
820 * Loop over logs of extent sizes. Order is irrelevant.
821 */
823 /*
824 * Get one summary datum.
825 */
829 }
830 /*
831 * If there are any, return success.
832 */
836 }
837 }
838 /*
839 * Found nothing, return failure.
840 */
843 }
845 /*
846 * Get a buffer for the bitmap or summary file block specified.
847 * The buffer is returned read and locked.
848 */
856 {
859 xfs_bmbt_irec_t map;
878 }
880 #ifdef DEBUG
881 /*
882 * Check that the given extent (block range) is allocated already.
883 */
891 {
895 }
896 #endif
898 /*
899 * Check that the given range is either all allocated (val = 0) or
900 * all free (val = 1).
901 */
911 {
924 /*
925 * Compute starting bitmap block number
926 */
928 /*
929 * Read the bitmap block.
930 */
934 }
936 /*
937 * Compute the starting word's address, and starting bit.
938 */
942 /*
943 * 0 (allocated) => all zero's; 1 (free) => all one's.
944 */
946 /*
947 * If not starting on a word boundary, deal with the first
948 * (partial) word.
949 */
951 /*
952 * Compute first bit not examined.
953 */
955 /*
956 * Mask of relevant bits.
957 */
959 /*
960 * Compute difference between actual and desired value.
961 */
963 /*
964 * Different, compute first wrong bit and return.
965 */
971 }
973 /*
974 * Go on to next block if that's where the next word is
975 * and we need the next word.
976 */
978 /*
979 * If done with this block, get the next one.
980 */
985 }
989 /*
990 * Go on to the next word in the buffer.
991 */
992 b++;
993 }
995 /*
996 * Starting on a word boundary, no partial word.
997 */
999 }
1000 /*
1001 * Loop over whole words in buffers. When we use up one buffer
1002 * we move on to the next one.
1003 */
1005 /*
1006 * Compute difference between actual and desired value.
1007 */
1009 /*
1010 * Different, compute first wrong bit and return.
1011 */
1017 }
1019 /*
1020 * Go on to next block if that's where the next word is
1021 * and we need the next word.
1022 */
1024 /*
1025 * If done with this block, get the next one.
1026 */
1031 }
1035 /*
1036 * Go on to the next word in the buffer.
1037 */
1038 b++;
1039 }
1040 }
1041 /*
1042 * If not ending on a word boundary, deal with the last
1043 * (partial) word.
1044 */
1046 /*
1047 * Mask of relevant bits.
1048 */
1050 /*
1051 * Compute difference between actual and desired value.
1052 */
1054 /*
1055 * Different, compute first wrong bit and return.
1056 */
1064 }
1065 /*
1066 * Successful, return.
1067 */
1072 }
1074 /*
1075 * Copy and transform the summary file, given the old and new
1076 * parameters in the mount structures.
1077 */
1083 {
1095 bbno--) {
1111 }
1112 }
1114 }
1116 /*
1117 * Searching backward from start to limit, find the first block whose
1118 * allocated/free state is different from start's.
1119 */
1127 {
1142 /*
1143 * Compute and read in starting bitmap block for starting block.
1144 */
1149 }
1151 /*
1152 * Get the first word's index & point to it.
1153 */
1158 /*
1159 * Compute match value, based on the bit at start: if 1 (free)
1160 * then all-ones, else all-zeroes.
1161 */
1163 /*
1164 * If the starting position is not word-aligned, deal with the
1165 * partial word.
1166 */
1168 /*
1169 * Calculate first (leftmost) bit number to look at,
1170 * and mask for all the relevant bits in this word.
1171 */
1174 firstbit;
1175 /*
1176 * Calculate the difference between the value there
1177 * and what we're looking for.
1178 */
1180 /*
1181 * Different. Mark where we are and return.
1182 */
1187 }
1189 /*
1190 * Go on to previous block if that's where the previous word is
1191 * and we need the previous word.
1192 */
1194 /*
1195 * If done with this block, get the previous one.
1196 */
1201 }
1206 /*
1207 * Go on to the previous word in the buffer.
1208 */
1209 b--;
1210 }
1212 /*
1213 * Starting on a word boundary, no partial word.
1214 */
1216 }
1217 /*
1218 * Loop over whole words in buffers. When we use up one buffer
1219 * we move on to the previous one.
1220 */
1222 /*
1223 * Compute difference between actual and desired value.
1224 */
1226 /*
1227 * Different, mark where we are and return.
1228 */
1233 }
1235 /*
1236 * Go on to previous block if that's where the previous word is
1237 * and we need the previous word.
1238 */
1240 /*
1241 * If done with this block, get the previous one.
1242 */
1247 }
1252 /*
1253 * Go on to the previous word in the buffer.
1254 */
1255 b--;
1256 }
1257 }
1258 /*
1259 * If not ending on a word boundary, deal with the last
1260 * (partial) word.
1261 */
1263 /*
1264 * Calculate first (leftmost) bit number to look at,
1265 * and mask for all the relevant bits in this word.
1266 */
1269 /*
1270 * Compute difference between actual and desired value.
1271 */
1273 /*
1274 * Different, mark where we are and return.
1275 */
1282 }
1283 /*
1284 * No match, return that we scanned the whole area.
1285 */
1289 }
1291 /*
1292 * Searching forward from start to limit, find the first block whose
1293 * allocated/free state is different from start's.
1294 */
1302 {
1317 /*
1318 * Compute and read in starting bitmap block for starting block.
1319 */
1324 }
1326 /*
1327 * Get the first word's index & point to it.
1328 */
1333 /*
1334 * Compute match value, based on the bit at start: if 1 (free)
1335 * then all-ones, else all-zeroes.
1336 */
1338 /*
1339 * If the starting position is not word-aligned, deal with the
1340 * partial word.
1341 */
1343 /*
1344 * Calculate last (rightmost) bit number to look at,
1345 * and mask for all the relevant bits in this word.
1346 */
1349 /*
1350 * Calculate the difference between the value there
1351 * and what we're looking for.
1352 */
1354 /*
1355 * Different. Mark where we are and return.
1356 */
1361 }
1363 /*
1364 * Go on to next block if that's where the next word is
1365 * and we need the next word.
1366 */
1368 /*
1369 * If done with this block, get the previous one.
1370 */
1375 }
1379 /*
1380 * Go on to the previous word in the buffer.
1381 */
1382 b++;
1383 }
1385 /*
1386 * Starting on a word boundary, no partial word.
1387 */
1389 }
1390 /*
1391 * Loop over whole words in buffers. When we use up one buffer
1392 * we move on to the next one.
1393 */
1395 /*
1396 * Compute difference between actual and desired value.
1397 */
1399 /*
1400 * Different, mark where we are and return.
1401 */
1406 }
1408 /*
1409 * Go on to next block if that's where the next word is
1410 * and we need the next word.
1411 */
1413 /*
1414 * If done with this block, get the next one.
1415 */
1420 }
1424 /*
1425 * Go on to the next word in the buffer.
1426 */
1427 b++;
1428 }
1429 }
1430 /*
1431 * If not ending on a word boundary, deal with the last
1432 * (partial) word.
1433 */
1435 /*
1436 * Calculate mask for all the relevant bits in this word.
1437 */
1439 /*
1440 * Compute difference between actual and desired value.
1441 */
1443 /*
1444 * Different, mark where we are and return.
1445 */
1452 }
1453 /*
1454 * No match, return that we scanned the whole area.
1455 */
1459 }
1461 /*
1462 * Mark an extent specified by start and len freed.
1463 * Updates all the summary information as well as the bitmap.
1464 */
1473 {
1480 /*
1481 * Modify the bitmap to mark this extent freed.
1482 */
1486 }
1487 /*
1488 * Assume we're freeing out of the middle of an allocated extent.
1489 * We need to find the beginning and end of the extent so we can
1490 * properly update the summary.
1491 */
1495 }
1496 /*
1497 * Find the next allocated block (end of allocated extent).
1498 */
1503 /*
1504 * If there are blocks not being freed at the front of the
1505 * old extent, add summary data for them to be allocated.
1506 */
1513 }
1514 }
1515 /*
1516 * If there are blocks not being freed at the end of the
1517 * old extent, add summary data for them to be allocated.
1518 */
1525 }
1526 }
1527 /*
1528 * Increment the summary information corresponding to the entire
1529 * (new) free extent.
1530 */
1535 }
1537 /*
1538 * Read and return the summary information for a given extent size,
1539 * bitmap block combination.
1540 * Keeps track of a current summary block, so we don't keep reading
1541 * it from the buffer cache.
1542 */
1552 {
1559 /*
1560 * Compute entry number in the summary file.
1561 */
1563 /*
1564 * Compute the block number in the summary file.
1565 */
1567 /*
1568 * If we have an old buffer, and the block number matches, use that.
1569 */
1572 /*
1573 * Otherwise we have to get the buffer.
1574 */
1576 /*
1577 * If there was an old one, get rid of it first.
1578 */
1584 }
1585 /*
1586 * Remember this buffer and block for the next call.
1587 */
1591 }
1592 }
1593 /*
1594 * Point to the summary information & copy it out.
1595 */
1598 /*
1599 * Drop the buffer if we're not asked to remember it.
1600 */
1604 }
1606 /*
1607 * Set the given range of bitmap bits to the given value.
1608 * Do whatever I/O and logging is required.
1609 */
1617 {
1630 /*
1631 * Compute starting bitmap block number.
1632 */
1634 /*
1635 * Read the bitmap block, and point to its data.
1636 */
1640 }
1642 /*
1643 * Compute the starting word's address, and starting bit.
1644 */
1648 /*
1649 * 0 (allocated) => all zeroes; 1 (free) => all ones.
1650 */
1652 /*
1653 * If not starting on a word boundary, deal with the first
1654 * (partial) word.
1655 */
1657 /*
1658 * Compute first bit not changed and mask of relevant bits.
1659 */
1662 /*
1663 * Set/clear the active bits.
1664 */
1667 else
1670 /*
1671 * Go on to the next block if that's where the next word is
1672 * and we need the next word.
1673 */
1675 /*
1676 * Log the changed part of this block.
1677 * Get the next one.
1678 */
1685 }
1689 /*
1690 * Go on to the next word in the buffer
1691 */
1692 b++;
1693 }
1695 /*
1696 * Starting on a word boundary, no partial word.
1697 */
1699 }
1700 /*
1701 * Loop over whole words in buffers. When we use up one buffer
1702 * we move on to the next one.
1703 */
1705 /*
1706 * Set the word value correctly.
1707 */
1710 /*
1711 * Go on to the next block if that's where the next word is
1712 * and we need the next word.
1713 */
1715 /*
1716 * Log the changed part of this block.
1717 * Get the next one.
1718 */
1725 }
1729 /*
1730 * Go on to the next word in the buffer
1731 */
1732 b++;
1733 }
1734 }
1735 /*
1736 * If not ending on a word boundary, deal with the last
1737 * (partial) word.
1738 */
1740 /*
1741 * Compute a mask of relevant bits.
1742 */
1745 /*
1746 * Set/clear the active bits.
1747 */
1750 else
1752 b++;
1753 }
1754 /*
1755 * Log any remaining changed bytes.
1756 */
1761 }
1763 /*
1764 * Read and modify the summary information for a given extent size,
1765 * bitmap block combination.
1766 * Keeps track of a current summary block, so we don't keep reading
1767 * it from the buffer cache.
1768 */
1778 {
1785 /*
1786 * Compute entry number in the summary file.
1787 */
1789 /*
1790 * Compute the block number in the summary file.
1791 */
1793 /*
1794 * If we have an old buffer, and the block number matches, use that.
1795 */
1798 /*
1799 * Otherwise we have to get the buffer.
1800 */
1802 /*
1803 * If there was an old one, get rid of it first.
1804 */
1810 }
1811 /*
1812 * Remember this buffer and block for the next call.
1813 */
1817 }
1818 }
1819 /*
1820 * Point to the summary information, modify and log it.
1821 */
1827 }
1829 /*
1830 * Visible (exported) functions.
1831 */
1833 /*
1834 * Grow the realtime area of the filesystem.
1835 */
1836 int
1840 {
1859 /*
1860 * Initial error checking.
1861 */
1870 /*
1871 * Read in the last block of the device, make sure it exists.
1872 */
1880 /*
1881 * Calculate new parameters. These are the final values to be reached.
1882 */
1891 /*
1892 * New summary size can't be more than half the size of
1893 * the log. This prevents us from getting a log overflow,
1894 * since we'll log basically the whole summary file at once.
1895 */
1898 /*
1899 * Get the old block counts for bitmap and summary inodes.
1900 * These can't change since other growfs callers are locked out.
1901 */
1904 /*
1905 * Allocate space to the bitmap and summary files, as necessary.
1906 */
1913 /*
1914 * Allocate a new (fake) mount/sb.
1915 */
1917 /*
1918 * Loop over the bitmap blocks.
1919 * We will do everything one bitmap block at a time.
1920 * Skip the current block if it is exactly full.
1921 * This also deals with the case where there were no rtextents before.
1922 */
1926 bmbno++) {
1932 /*
1933 * Calculate new sb and mount fields for this round.
1934 */
1946 nrsumsize =
1951 /*
1952 * Start a transaction, get the log reservation.
1953 */
1958 /*
1959 * Lock out other callers by grabbing the bitmap inode lock.
1960 */
1963 /*
1964 * Update the bitmap inode's size.
1965 */
1970 /*
1971 * Get the summary inode into the transaction.
1972 */
1975 /*
1976 * Update the summary inode's size.
1977 */
1980 /*
1981 * Copy summary data from old to new sizes.
1982 * Do this when the real size (not block-aligned) changes.
1983 */
1989 }
1990 /*
1991 * Update superblock fields.
1992 */
2008 /*
2009 * Free new extent.
2010 */
2015 error_cancel:
2018 }
2019 /*
2020 * Mark more blocks free in the superblock.
2021 */
2024 /*
2025 * Update mp values into the real mp structure.
2026 */
2033 }
2035 /*
2036 * Free the fake mp structure.
2037 */
2041 }
2043 /*
2044 * Allocate an extent in the realtime subvolume, with the usual allocation
2045 * parameters. The length units are all in realtime extents, as is the
2046 * result block number.
2047 */
2059 {
2069 /*
2070 * If prod is set then figure out what to do to minlen and maxlen.
2071 */
2073 xfs_extlen_t i;
2082 }
2083 }
2086 /*
2087 * Allocate by size, or near another block, or exactly at some block.
2088 */
2105 }
2109 /*
2110 * If it worked, update the superblock.
2111 */
2118 else
2120 }
2123 }
2125 /*
2126 * Free an extent in the realtime subvolume. Length is expressed in
2127 * realtime extents, as is the block number.
2128 */
2134 {
2145 #if defined(__KERNEL__) && defined(DEBUG)
2146 /*
2147 * Check to see that this whole range is currently allocated.
2148 */
2149 {
2155 }
2157 }
2158 #endif
2160 /*
2161 * Free the range of realtime blocks.
2162 */
2166 }
2167 /*
2168 * Mark more blocks free in the superblock.
2169 */
2171 /*
2172 * If we've now freed all the blocks, reset the file sequence
2173 * number to 0.
2174 */
2181 }
2183 }
2185 /*
2186 * Initialize realtime fields in the mount structure.
2187 */
2191 {
2203 }
2210 /*
2211 * Check that the realtime section is an ok size.
2212 */
2219 }
2226 }
2229 }
2231 /*
2232 * Get the bitmap and summary inodes into the mount structure
2233 * at mount time.
2234 */
2238 {
2254 }
2257 }
2259 void
2262 {
2267 }
2269 /*
2270 * Pick an extent for allocation at the start of a new realtime file.
2271 * Use the sequence number stored in the atime field of the bitmap inode.
2272 * Translate this to a fraction of the rtextents, and return the product
2273 * of rtextents and the fraction.
2274 * The fraction sequence is 0, 1/2, 1/4, 3/4, 1/8, ..., 7/8, 1/16, ...
2275 */
2282 {
2295 }
2307 }
2312 }