| blob | 837d42f61464b3a7e06bd8cf625d8e1a96fbfd5e |
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) International Business Machines Corp., 2000-2004
4 */
6 /*
7 * jfs_dtree.c: directory B+-tree manager
8 *
9 * B+-tree with variable length key directory:
10 *
11 * each directory page is structured as an array of 32-byte
12 * directory entry slots initialized as a freelist
13 * to avoid search/compaction of free space at insertion.
14 * when an entry is inserted, a number of slots are allocated
15 * from the freelist as required to store variable length data
16 * of the entry; when the entry is deleted, slots of the entry
17 * are returned to freelist.
18 *
19 * leaf entry stores full name as key and file serial number
20 * (aka inode number) as data.
21 * internal/router entry stores sufffix compressed name
22 * as key and simple extent descriptor as data.
23 *
24 * each directory page maintains a sorted entry index table
25 * which stores the start slot index of sorted entries
26 * to allow binary search on the table.
27 *
28 * directory starts as a root/leaf page in on-disk inode
29 * inline data area.
30 * when it becomes full, it starts a leaf of a external extent
31 * of length of 1 block. each time the first leaf becomes full,
32 * it is extended rather than split (its size is doubled),
33 * until its length becoms 4 KBytes, from then the extent is split
34 * with new 4 Kbyte extent when it becomes full
35 * to reduce external fragmentation of small directories.
36 *
37 * blah, blah, blah, for linear scan of directory in pieces by
38 * readdir().
39 *
40 *
41 * case-insensitive directory file system
42 *
43 * names are stored in case-sensitive way in leaf entry.
44 * but stored, searched and compared in case-insensitive (uppercase) order
45 * (i.e., both search key and entry key are folded for search/compare):
46 * (note that case-sensitive order is BROKEN in storage, e.g.,
47 * sensitive: Ad, aB, aC, aD -> insensitive: aB, aC, aD, Ad
48 *
49 * entries which folds to the same key makes up a equivalent class
50 * whose members are stored as contiguous cluster (may cross page boundary)
51 * but whose order is arbitrary and acts as duplicate, e.g.,
52 * abc, Abc, aBc, abC)
53 *
54 * once match is found at leaf, requires scan forward/backward
55 * either for, in case-insensitive search, duplicate
56 * or for, in case-sensitive search, for exact match
57 *
58 * router entry must be created/stored in case-insensitive way
59 * in internal entry:
60 * (right most key of left page and left most key of right page
61 * are folded, and its suffix compression is propagated as router
62 * key in parent)
63 * (e.g., if split occurs <abc> and <aBd>, <ABD> trather than <aB>
64 * should be made the router key for the split)
65 *
66 * case-insensitive search:
67 *
68 * fold search key;
69 *
70 * case-insensitive search of B-tree:
71 * for internal entry, router key is already folded;
72 * for leaf entry, fold the entry key before comparison.
73 *
74 * if (leaf entry case-insensitive match found)
75 * if (next entry satisfies case-insensitive match)
76 * return EDUPLICATE;
77 * if (prev entry satisfies case-insensitive match)
78 * return EDUPLICATE;
79 * return match;
80 * else
81 * return no match;
82 *
83 * serialization:
84 * target directory inode lock is being held on entry/exit
85 * of all main directory service routines.
86 *
87 * log based recovery:
88 */
90 #include <linux/fs.h>
91 #include <linux/quotaops.h>
92 #include <linux/slab.h>
101 /* dtree split parameter */
104 s16 index;
105 s16 nslot;
109 };
111 #define DT_PAGE(IP, MP) BT_PAGE(IP, MP, dtpage_t, i_dtroot)
113 /* get page buffer for specified block address */
114 #define DT_GETPAGE(IP, BN, MP, SIZE, P, RC) \
115 do { \
116 BT_GETPAGE(IP, BN, MP, dtpage_t, SIZE, P, RC, i_dtroot); \
117 if (!(RC)) { \
118 if (((P)->header.nextindex > \
119 (((BN) == 0) ? DTROOTMAXSLOT : (P)->header.maxslot)) || \
120 ((BN) && ((P)->header.maxslot > DTPAGEMAXSLOT))) { \
121 BT_PUTPAGE(MP); \
122 jfs_error((IP)->i_sb, \
124 MP = NULL; \
125 RC = -EIO; \
126 } \
127 } \
128 } while (0)
130 /* for consistency */
131 #define DT_PUTPAGE(MP) BT_PUTPAGE(MP)
133 #define DT_GETSEARCH(IP, LEAF, BN, MP, P, INDEX) \
134 BT_GETSEARCH(IP, LEAF, BN, MP, dtpage_t, P, INDEX, i_dtroot)
136 /*
137 * forward references
138 */
185 #define ciToUpper(c) UniStrupr((c)->name)
187 /*
188 * read_index_page()
189 *
190 * Reads a page of a directory's index table.
191 * Having metadata mapped into the directory inode's address space
192 * presents a multitude of problems. We avoid this by mapping to
193 * the absolute address space outside of the *_metapage routines
194 */
196 {
198 s64 xaddr;
200 s32 xlen;
207 }
209 /*
210 * get_index_page()
211 *
212 * Same as get_index_page(), but get's a new page without reading
213 */
215 {
217 s64 xaddr;
219 s32 xlen;
226 }
228 /*
229 * find_index()
230 *
231 * Returns dtree page containing directory table entry for specified
232 * index and pointer to its entry.
233 *
234 * mp must be released by caller.
235 */
238 {
240 s64 blkno;
241 s64 offset;
249 maxWarnings--;
250 }
252 }
257 }
260 /*
261 * Inline directory table
262 */
274 }
278 }
282 }
284 slot =
286 page_offset);
287 }
289 }
292 u32 index)
293 {
305 /*
306 * Linelock slot size is twice the size of directory table
307 * slot size. 512 entries per page.
308 */
312 }
314 /*
315 * add_index()
316 *
317 * Adds an entry to the directory index table. This is used to provide
318 * each directory entry with a persistent index in which to resume
319 * directory traversals
320 */
322 {
326 u64 blkno;
328 u32 index;
332 s64 offset;
333 uint page_offset;
335 s64 xaddr;
343 }
348 /*
349 * i_size reflects size of index table, or 8 bytes per entry.
350 */
353 /*
354 * dir table fits inline within inode
355 */
364 }
368 /*
369 * It's time to move the inline table to an external
370 * page and begin to build the xtree
371 */
377 }
379 /*
380 * Save the table, we're going to overwrite it with the
381 * xtree root
382 */
385 /*
386 * Initialize empty x-tree
387 */
390 /*
391 * Add the first block to the xtree
392 */
394 /* This really shouldn't fail */
401 }
411 }
426 /*
427 * Logging is now directed by xtree tlocks
428 */
430 }
436 /*
437 * This will be the beginning of a new page
438 */
443 }
448 else
456 }
460 dirtab_slot =
471 clean_up:
476 }
478 /*
479 * free_index()
480 *
481 * Marks an entry to the directory index table as free.
482 */
484 {
486 s64 lblock;
504 }
506 /*
507 * modify_index()
508 *
509 * Changes an entry in the directory index table
510 */
513 {
529 }
531 /*
532 * read_index()
533 *
534 * reads a directory table slot
535 */
538 {
539 s64 lblock;
546 }
554 }
556 /*
557 * dtSearch()
558 *
559 * function:
560 * Search for the entry with specified key
561 *
562 * parameter:
563 *
564 * return: 0 - search result on stack, leaf page pinned;
565 * errno - I/O error
566 */
569 {
572 s64 bn;
580 ino_t inumber;
585 GFP_NOFS);
589 }
592 /* uppercase search key for c-i directory */
596 /* only uppercase if case-insensitive support is on */
599 }
602 /* init level count for max pages to split */
605 /*
606 * search down tree from root:
607 *
608 * between two consecutive entries of <Ki, Pi> and <Kj, Pj> of
609 * internal page, child page Pi contains entry with k, Ki <= K < Kj.
610 *
611 * if entry with search key K is not found
612 * internal page search find the entry with largest key Ki
613 * less than K which point to the child page to search;
614 * leaf page search find the entry with smallest key Kj
615 * greater than K so that the returned index is the position of
616 * the entry to be shifted right for insertion of new entry.
617 * for empty tree, search key is greater than any key of the tree.
618 *
619 * by convention, root bn = 0.
620 */
622 /* get/pin the page to search */
627 /* get sorted entry table of the page */
630 /*
631 * binary search with search key K on the current page.
632 */
637 /* uppercase leaf name to compare */
638 cmp =
642 /* router key is in uppercase */
647 }
649 /*
650 * search hit
651 */
652 /* search hit - leaf page:
653 * return the entry found
654 */
659 /*
660 * search for JFS_LOOKUP
661 */
666 }
668 /*
669 * search for JFS_CREATE
670 */
675 }
677 /*
678 * search for JFS_REMOVE or JFS_RENAME
679 */
685 }
687 /*
688 * JFS_REMOVE|JFS_FINDDIR|JFS_RENAME
689 */
690 /* save search result */
699 }
701 /* search hit - internal page:
702 * descend/search its child page
703 */
705 }
710 }
711 }
713 /*
714 * search miss
715 *
716 * base is the smallest index with key (Kj) greater than
717 * search key (K) and may be zero or (maxindex + 1) index.
718 */
719 /*
720 * search miss - leaf page
721 *
722 * return location of entry (base) where new entry with
723 * search key K is to be inserted.
724 */
726 /*
727 * search for JFS_LOOKUP, JFS_REMOVE, or JFS_RENAME
728 */
733 }
735 /*
736 * search for JFS_CREATE|JFS_FINDDIR:
737 *
738 * save search result
739 */
748 }
750 /*
751 * search miss - internal page
752 *
753 * if base is non-zero, decrement base by one to get the parent
754 * entry of the child page to search.
755 */
758 /*
759 * go down to child page
760 */
761 getChild:
762 /* update max. number of pages to split */
764 /* Something's corrupted, mark filesystem dirty so
765 * chkdsk will fix it.
766 */
771 }
774 /* push (bn, index) of the parent page/entry */
777 /* get the child page block number */
782 /* unpin the parent page */
784 }
786 out:
789 dtSearch_Exit1:
793 dtSearch_Exit2:
796 }
799 /*
800 * dtInsert()
801 *
802 * function: insert an entry to directory tree
803 *
804 * parameter:
805 *
806 * return: 0 - success;
807 * errno - failure;
808 */
811 {
815 s64 bn;
818 ddata_t data;
824 /*
825 * retrieve search result
826 *
827 * dtSearch() returns (leaf page pinned, index at which to insert).
828 * n.b. dtSearch() may return index of (maxindex + 1) of
829 * the full page.
830 */
833 /*
834 * insert entry for new key
835 */
840 }
847 }
850 /*
851 * leaf page does not have enough room for new entry:
852 *
853 * extend/split the leaf page;
854 *
855 * dtSplitUp() will insert the entry and unpin the leaf page.
856 */
865 }
867 /*
868 * leaf page does have enough room for new entry:
869 *
870 * insert the new data entry into the leaf page;
871 */
873 /*
874 * acquire a transaction lock on the leaf page
875 */
881 /* linelock header */
888 /* linelock stbl of non-root leaf page */
898 }
900 /* unpin the leaf page */
904 }
907 /*
908 * dtSplitUp()
909 *
910 * function: propagate insertion bottom up;
911 *
912 * parameter:
913 *
914 * return: 0 - success;
915 * errno - failure;
916 * leaf page unpinned;
917 */
920 {
944 /* get split page */
953 }
955 /*
956 * split leaf page
957 *
958 * The split routines insert the new entry, and
959 * acquire txLock as appropriate.
960 */
961 /*
962 * split root leaf page:
963 */
965 /*
966 * allocate a single extent child page
967 */
973 xlen++;
977 }
989 else
998 }
1000 /*
1001 * extend first leaf page
1002 *
1003 * extend the 1st extent if less than buffer page size
1004 * (dtExtendPage() reurns leaf page unpinned)
1005 */
1015 else
1018 /* Allocate blocks to quota. */
1037 /* free relocated extent */
1041 /* free extended delta */
1045 }
1050 extendOut:
1053 }
1055 /*
1056 * split leaf page <sp> into <sp> and a new right page <rp>.
1057 *
1058 * return <rp> pinned and its extent descriptor <rpxd>
1059 */
1060 /*
1061 * allocate new directory page extent and
1062 * new index page(s) to cover page split(s)
1063 *
1064 * allocation hint: ?
1065 */
1075 }
1079 /* undo allocation */
1081 }
1087 /* undo allocation */
1089 }
1094 /*
1095 * propagate up the router entry for the leaf page just split
1096 *
1097 * insert a router entry for the new page into the parent page,
1098 * propagate the insert/split up the tree by walking back the stack
1099 * of (bn of parent page, index of child page entry in parent page)
1100 * that were traversed during the search for the page that split.
1101 *
1102 * the propagation of insert/split up the tree stops if the root
1103 * splits or the page inserted into doesn't have to split to hold
1104 * the new entry.
1105 *
1106 * the parent entry for the split page remains the same, and
1107 * a new entry is inserted at its right with the first key and
1108 * block number of the new right page.
1109 *
1110 * There are a maximum of 4 pages pinned at any time:
1111 * two children, left parent and right parent (when the parent splits).
1112 * keep the child pages pinned while working on the parent.
1113 * make sure that all pins are released at exit.
1114 */
1116 /* parent page specified by stack frame <parent> */
1118 /* keep current child pages (<lp>, <rp>) pinned */
1122 /*
1123 * insert router entry in parent for new right child page <rp>
1124 */
1125 /* get the parent page <sp> */
1131 }
1133 /*
1134 * The new key entry goes ONE AFTER the index of parent entry,
1135 * because the split was to the right.
1136 */
1139 /*
1140 * compute the key for the router entry
1141 *
1142 * key suffix compression:
1143 * for internal pages that have leaf pages as children,
1144 * retain only what's needed to distinguish between
1145 * the new entry and the entry on the page to its left.
1146 * If the keys compare equal, retain the entire key.
1147 *
1148 * note that compression is performed only at computing
1149 * router key at the lowest internal level.
1150 * further compression of the key between pairs of higher
1151 * level internal pages loses too much information and
1152 * the search may fail.
1153 * (e.g., two adjacent leaf pages of {a, ..., x} {xx, ...,}
1154 * results in two adjacent parent entries (a)(xx).
1155 * if split occurs between these two entries, and
1156 * if compression is applied, the router key of parent entry
1157 * of right page (x) will divert search for x into right
1158 * subtree and miss x in the left subtree.)
1159 *
1160 * the entire key must be retained for the next-to-leftmost
1161 * internal key at any level of the tree, or search may fail
1162 * (e.g., ?)
1163 */
1166 /*
1167 * compute the length of prefix for suffix compression
1168 * between last entry of left page and first entry
1169 * of right page
1170 */
1173 /* compute uppercase router prefix key */
1183 }
1185 /* next to leftmost entry of
1186 lowest internal level */
1188 /* compute uppercase router key */
1194 }
1207 }
1209 /* unpin left child page */
1212 /*
1213 * compute the data for the router entry
1214 */
1217 /*
1218 * parent page is full - split the parent page
1219 */
1221 /* init for parent page split */
1226 /* split->data = data; */
1228 /* unpin right child page */
1231 /* The split routines insert the new entry,
1232 * acquire txLock as appropriate.
1233 * return <rp> pinned and its block number <rbn>.
1234 */
1241 }
1243 /* smp and rmp are pinned */
1244 }
1245 /*
1246 * parent page is not full - insert router entry in parent page
1247 */
1250 /*
1251 * acquire a transaction lock on the parent page
1252 */
1258 /* linelock header */
1263 /* linelock stbl of non-root parent page */
1265 lv++;
1272 }
1276 /* exit propagate up */
1278 }
1279 }
1281 /* unpin current split and its right page */
1285 /*
1286 * free remaining extents allocated for split
1287 */
1288 splitOut:
1294 freeKeyName:
1297 /* Rollback quota allocation */
1301 dtSplitUp_Exit:
1304 }
1307 /*
1308 * dtSplitPage()
1309 *
1310 * function: Split a non-root page of a btree.
1311 *
1312 * parameter:
1313 *
1314 * return: 0 - success;
1315 * errno - failure;
1316 * return split and new page pinned;
1317 */
1320 {
1329 s64 nextbn;
1344 /* get split page */
1348 /*
1349 * allocate the new right page for the split
1350 */
1359 /* Allocate blocks to quota. */
1364 }
1369 /*
1370 * acquire a transaction lock on the new right page
1371 */
1380 /*
1381 * acquire a transaction lock on the split page
1382 *
1383 * action:
1384 */
1388 /* linelock header of split page */
1395 /*
1396 * initialize/update sibling pointers between sp and rp
1397 */
1403 /*
1404 * initialize new right page
1405 */
1408 /* compute sorted entry table at start of extent data area */
1416 /* init freelist */
1421 /*
1422 * sequential append at tail: append without split
1423 *
1424 * If splitting the last page on a level because of appending
1425 * a entry to it (skip is maxentry), it's likely that the access is
1426 * sequential. Adding an empty page on the side of the level is less
1427 * work and can push the fill factor much higher than normal.
1428 * If we're wrong it's no big deal, we'll just do the split the right
1429 * way next time.
1430 * (It may look like it's equally easy to do a similar hack for
1431 * reverse sorted data, that is, split the tree left,
1432 * but it's not. Be my guest.)
1433 */
1435 /* linelock header + stbl (first slot) of new page */
1441 /*
1442 * initialize freelist of new right page
1443 */
1449 /* insert entry at the first entry of the new right page */
1453 }
1455 /*
1456 * non-sequential insert (at possibly middle page)
1457 */
1459 /*
1460 * update prev pointer of previous right sibling page;
1461 */
1467 }
1470 /*
1471 * acquire a transaction lock on the next page
1472 */
1478 /* linelock header of previous right sibling page */
1487 }
1489 /*
1490 * split the data between the split and right pages.
1491 */
1496 /*
1497 * compute fill factor for split pages
1498 *
1499 * <nxt> traces the next entry to move to rp
1500 * <off> traces the next entry to stay in sp
1501 */
1506 /* check for fill factor with new entry size */
1515 else
1517 namlen);
1527 }
1530 }
1535 }
1537 /* <nxt> poins to the 1st entry to move */
1539 /*
1540 * move entries to right page
1541 *
1542 * dtMoveEntry() initializes rp and reserves entry for insertion
1543 *
1544 * split page moved out entries are linelocked;
1545 * new/right page moved in entries are linelocked;
1546 */
1547 /* linelock header + stbl of new right page */
1557 /*
1558 * finalize freelist of new right page
1559 */
1566 /*
1567 * Update directory index table for entries now in right page
1568 */
1570 s64 lblock;
1578 }
1581 }
1583 /*
1584 * the skipped index was on the left page,
1585 */
1587 /* insert the new entry in the split page */
1590 /* linelock stbl of split page */
1599 }
1600 /*
1601 * the skipped index was on the right page,
1602 */
1604 /* adjust the skip index to reflect the new position */
1607 /* insert the new entry in the right page */
1609 }
1611 out:
1616 }
1619 /*
1620 * dtExtendPage()
1621 *
1622 * function: extend 1st/only directory leaf page
1623 *
1624 * parameter:
1625 *
1626 * return: 0 - success;
1627 * errno - failure;
1628 * return extended page pinned;
1629 */
1632 {
1651 uint type;
1655 /* get page to extend */
1659 /* get parent/root page */
1665 /*
1666 * extend the extent
1667 */
1675 /* in-place extension */
1678 }
1679 /* relocation */
1683 /* save moved extent descriptor for later free */
1690 /*
1691 * Update directory index table to reflect new page address
1692 */
1694 s64 lblock;
1699 ldtentry =
1704 }
1707 }
1708 }
1710 /*
1711 * extend the page
1712 */
1718 /*
1719 * acquire a transaction lock on the extended/leaf page
1720 */
1725 /* update buffer extent descriptor of extended page */
1729 /*
1730 * copy old stbl to new stbl at start of extended area
1731 */
1740 /*
1741 * in-line extension: linelock old area of extended page
1742 */
1744 /* linelock header */
1748 lv++;
1750 /* linelock new stbl of extended page */
1753 }
1754 /*
1755 * relocation: linelock whole relocated area
1756 */
1760 }
1766 /* sp->header.nextindex remains the same */
1768 /*
1769 * add old stbl region at head of freelist
1770 */
1777 }
1781 /*
1782 * append free region of newly extended area at tail of freelist
1783 */
1784 /* init free region of newly extended area */
1791 /* append new free region at tail of old freelist */
1802 }
1806 /*
1807 * insert the new entry
1808 */
1812 /*
1813 * linelock any freeslots residing in old extent
1814 */
1819 }
1821 /*
1822 * update parent entry on the parent/root page
1823 */
1824 /*
1825 * acquire a transaction lock on the parent/root page
1826 */
1831 /* linelock parent entry - 1st slot */
1836 /* update the parent pxd for page extension */
1842 }
1845 /*
1846 * dtSplitRoot()
1847 *
1848 * function:
1849 * split the full root page into
1850 * original/root/split page and new right page
1851 * i.e., root remains fixed in tree anchor (inode) and
1852 * the root is copied to a single new right child page
1853 * since root page << non-root page, and
1854 * the split root page contains a single entry for the
1855 * new right child page.
1856 *
1857 * parameter:
1858 *
1859 * return: 0 - success;
1860 * errno - failure;
1861 * return new page pinned;
1862 */
1865 {
1871 s64 rbn;
1886 /* get split root page */
1890 /*
1891 * allocate/initialize a single (right) child page
1892 *
1893 * N.B. at first split, a one (or two) block to fit new entry
1894 * is allocated; at subsequent split, a full page is allocated;
1895 */
1908 /* Allocate blocks to quota. */
1913 }
1916 /*
1917 * acquire a transaction lock on the new right page
1918 */
1926 /* initialize sibling pointers */
1930 /*
1931 * move in-line root page into new right page extent
1932 */
1933 /* linelock header + copied entries + new stbl (1st slot) in new page */
1944 /* copy old stbl to new stbl at start of extended area */
1950 /* copy old data area to start of new data area */
1953 /*
1954 * append free region of newly extended area at tail of freelist
1955 */
1956 /* init free region of newly extended area */
1963 /* append new free region at tail of old freelist */
1976 }
1980 /*
1981 * Update directory index table for entries now in right page
1982 */
1984 s64 lblock;
1993 }
1996 }
1997 /*
1998 * insert the new entry into the new right/child page
1999 * (skip index in the new right page will not change)
2000 */
2003 /*
2004 * reset parent/root page
2005 *
2006 * set the 1st entry offset to 0, which force the left-most key
2007 * at any level of the tree to be less than any search key.
2008 *
2009 * The btree comparison code guarantees that the left-most key on any
2010 * level of the tree is never used, so it doesn't need to be filled in.
2011 */
2013 /*
2014 * acquire a transaction lock on the root page (in-memory inode)
2015 */
2019 /* linelock root */
2026 /* update page header of root */
2030 }
2032 /* init the first entry */
2043 /* init freelist */
2047 /* init free region of remaining area */
2058 }
2061 /*
2062 * dtDelete()
2063 *
2064 * function: delete the entry(s) referenced by a key.
2065 *
2066 * parameter:
2067 *
2068 * return:
2069 */
2072 {
2074 s64 bn;
2089 /*
2090 * search for the entry to delete:
2091 *
2092 * dtSearch() returns (leaf page pinned, index at which to delete).
2093 */
2097 /* retrieve search result */
2100 /*
2101 * We need to find put the index of the next entry into the
2102 * directory index table in order to resume a readdir from this
2103 * entry.
2104 */
2110 /*
2111 * Last entry in this leaf page
2112 */
2117 /* Read next leaf page */
2124 ldtentry =
2127 next_index =
2130 }
2131 }
2133 ldtentry =
2136 }
2138 }
2139 /*
2140 * the leaf page becomes empty, delete the page
2141 */
2143 /* delete empty page */
2145 }
2146 /*
2147 * the leaf page has other entries remaining:
2148 *
2149 * delete the entry from the leaf page.
2150 */
2153 /*
2154 * acquire a transaction lock on the leaf page
2155 */
2159 /*
2160 * Do not assume that dtlck->index will be zero. During a
2161 * rename within a directory, this transaction may have
2162 * modified this page already when adding the new entry.
2163 */
2165 /* linelock header */
2173 /* linelock stbl of non-root leaf page */
2184 }
2186 /* free the leaf entry */
2189 /*
2190 * Update directory index table for entries moved in stbl
2191 */
2193 s64 lblock;
2198 ldtentry =
2203 }
2206 }
2209 }
2212 }
2215 /*
2216 * dtDeleteUp()
2217 *
2218 * function:
2219 * free empty pages as propagating deletion up the tree
2220 *
2221 * parameter:
2222 *
2223 * return:
2224 */
2227 {
2240 /*
2241 * keep the root leaf page which has become empty
2242 */
2244 /*
2245 * reset the root
2246 *
2247 * dtInitRoot() acquires txlock on the root
2248 */
2254 }
2256 /*
2257 * free the non-root leaf page
2258 */
2259 /*
2260 * acquire a transaction lock on the page
2261 *
2262 * write FREEXTENT|NOREDOPAGE log record
2263 * N.B. linelock is overlaid as freed extent descriptor, and
2264 * the buffer page is freed;
2265 */
2272 /* update sibling pointers */
2276 }
2280 /* Free quota allocation. */
2283 /* free/invalidate its buffer page */
2286 /*
2287 * propagate page deletion up the directory tree
2288 *
2289 * If the delete from the parent page makes it empty,
2290 * continue all the way up the tree.
2291 * stop if the root page is reached (which is never deleted) or
2292 * if the entry deletion does not empty the page.
2293 */
2295 /* pin the parent page <sp> */
2300 /*
2301 * free the extent of the child page deleted
2302 */
2305 /*
2306 * delete the entry for the child page from parent
2307 */
2310 /*
2311 * the parent has the single entry being deleted:
2312 *
2313 * free the parent page which has become empty.
2314 */
2316 /*
2317 * keep the root internal page which has become empty
2318 */
2320 /*
2321 * reset the root
2322 *
2323 * dtInitRoot() acquires txlock on the root
2324 */
2330 }
2331 /*
2332 * free the parent page
2333 */
2335 /*
2336 * acquire a transaction lock on the page
2337 *
2338 * write FREEXTENT|NOREDOPAGE log record
2339 */
2340 tlck =
2348 /* update sibling pointers */
2352 }
2356 /* Free quota allocation */
2359 /* free/invalidate its buffer page */
2362 /* propagate up */
2364 }
2365 }
2367 /*
2368 * the parent has other entries remaining:
2369 *
2370 * delete the router entry from the parent page.
2371 */
2373 /*
2374 * acquire a transaction lock on the page
2375 *
2376 * action: router entry deletion
2377 */
2381 /* linelock header */
2389 /* linelock stbl of non-root leaf page */
2392 lv++;
2396 }
2403 }
2405 /* free the router entry */
2408 /* reset key of new leftmost entry of level (for consistency) */
2413 /* unpin the parent page */
2416 /* exit propagation up */
2418 }
2424 }
2426 #ifdef _NOTYET
2427 /*
2428 * NAME: dtRelocate()
2429 *
2430 * FUNCTION: relocate dtpage (internal or leaf) of directory;
2431 * This function is mainly used by defragfs utility.
2432 */
2434 s64 nxaddr)
2435 {
2439 s64 bn;
2456 xlen);
2458 /*
2459 * 1. get the internal parent dtpage covering
2460 * router entry for the tartget page to be relocated;
2461 */
2466 /* retrieve search result */
2470 /*
2471 * 2. relocate the target dtpage
2472 */
2473 /* read in the target page from src extent */
2476 /* release the pinned parent page */
2479 }
2481 /*
2482 * read in sibling pages if any to update sibling pointers;
2483 */
2492 }
2493 }
2505 }
2506 }
2508 /* at this point, all xtpages to be updated are in memory */
2510 /*
2511 * update sibling pointers of sibling dtpages if any;
2512 */
2516 /* linelock header */
2525 }
2530 /* linelock header */
2539 }
2541 /*
2542 * update the target dtpage to be relocated
2543 *
2544 * write LOG_REDOPAGE of LOG_NEW type for dst page
2545 * for the whole target page (logredo() will apply
2546 * after image and update bmap for allocation of the
2547 * dst extent), and update bmap for allocation of
2548 * the dst extent;
2549 */
2552 /* linelock header */
2556 /* update the self address in the dtpage header */
2560 /* the dst page is the same as the src page, i.e.,
2561 * linelock for afterimage of the whole page;
2562 */
2567 /* update the buffer extent descriptor of the dtpage */
2570 /* unpin the relocated page */
2574 /* the moved extent is dtpage, then a LOG_NOREDOPAGE log rec
2575 * needs to be written (in logredo(), the LOG_NOREDOPAGE log rec
2576 * will also force a bmap update ).
2577 */
2579 /*
2580 * 3. acquire maplock for the source extent to be freed;
2581 */
2582 /* for dtpage relocation, write a LOG_NOREDOPAGE record
2583 * for the source dtpage (logredo() will init NoRedoPage
2584 * filter and will also update bmap for free of the source
2585 * dtpage), and upadte bmap for free of the source dtpage;
2586 */
2594 /*
2595 * 4. update the parent router entry for relocation;
2596 *
2597 * acquire tlck for the parent entry covering the target dtpage;
2598 * write LOG_REDOPAGE to apply after image only;
2599 */
2605 /* update the PXD with the new address */
2613 /* unpin the parent dtpage */
2617 }
2619 /*
2620 * NAME: dtSearchNode()
2621 *
2622 * FUNCTION: Search for an dtpage containing a specified address
2623 * This function is mainly used by defragfs utility.
2624 *
2625 * NOTE: Search result on stack, the found page is pinned at exit.
2626 * The result page must be an internal dtpage.
2627 * lmxaddr give the address of the left most page of the
2628 * dtree level, in which the required dtpage resides.
2629 */
2632 {
2634 s64 bn;
2645 /*
2646 * descend tree to the level with specified leftmost page
2647 *
2648 * by convention, root bn = 0.
2649 */
2651 /* get/pin the page to search */
2656 /* does the xaddr of leftmost page of the levevl
2657 * matches levevl search key ?
2658 */
2665 /*
2666 * descend down to leftmost child page
2667 */
2671 }
2673 /* get the leftmost entry */
2677 /* get the child page block address */
2680 /* unpin the parent page */
2682 }
2684 /*
2685 * search each page at the current levevl
2686 */
2687 loop:
2692 /* found the specified router entry */
2701 }
2702 }
2704 /* get the right sibling page if any */
2710 }
2712 /* unpin current page */
2715 /* get the right sibling page */
2721 }
2724 /*
2725 * dtRelink()
2726 *
2727 * function:
2728 * link around a freed page.
2729 *
2730 * parameter:
2731 * fp: page to be freed
2732 *
2733 * return:
2734 */
2736 {
2747 /* update prev pointer of the next page */
2754 /*
2755 * acquire a transaction lock on the next page
2756 *
2757 * action: update prev pointer;
2758 */
2764 /* linelock header */
2774 }
2776 /* update next pointer of the previous page */
2783 /*
2784 * acquire a transaction lock on the prev page
2785 *
2786 * action: update next pointer;
2787 */
2793 /* linelock header */
2803 }
2806 }
2809 /*
2810 * dtInitRoot()
2811 *
2812 * initialize directory root (inline in inode)
2813 */
2815 {
2823 u16 xflag_save;
2825 /*
2826 * If this was previously an non-empty directory, we need to remove
2827 * the old directory table.
2828 */
2832 /*
2833 * We're playing games with the tid's xflag. If
2834 * we're removing a regular file, the file's xtree
2835 * is committed with COMMIT_PMAP, but we always
2836 * commit the directories xtree with COMMIT_PWMAP.
2837 */
2840 /*
2841 * xtTruncate isn't guaranteed to fully truncate
2842 * the xtree. The caller needs to check i_size
2843 * after committing the transaction to see if
2844 * additional truncation is needed. The
2845 * COMMIT_Stale flag tells caller that we
2846 * initiated the truncation.
2847 */
2859 /*
2860 * acquire a transaction lock on the root
2861 *
2862 * action: directory initialization;
2863 */
2868 /* linelock root */
2881 /* init freelist */
2885 /* init data area of root */
2893 /* init '..' entry */
2897 }
2899 /*
2900 * add_missing_indices()
2901 *
2902 * function: Fix dtree page in which one or more entries has an invalid index.
2903 * fsck.jfs should really fix this, but it currently does not.
2904 * Called from jfs_readdir when bad index is detected.
2905 */
2907 {
2911 uint index;
2917 tid_t tid;
2927 }
2950 }
2951 }
2955 end:
2957 }
2959 /*
2960 * Buffer to hold directory entry info while traversing a dtree page
2961 * before being fed to the filldir function
2962 */
2964 loff_t position;
2966 u16 name_len;
2968 };
2970 /*
2971 * function to determine next variable-sized jfs_dirent in buffer
2972 */
2974 {
2980 }
2982 /*
2983 * jfs_readdir()
2984 *
2985 * function: read directory entries sequentially
2986 * from the specified entry offset
2987 *
2988 * parameter:
2989 *
2990 * return: offset = (pn, index) of start entry
2991 * of next jfs_readdir()/dtRead()
2992 */
2994 {
3000 s16 pn;
3001 s16 index;
3002 s32 unused;
3004 s64 bn;
3016 u32 dir_index;
3028 /*
3029 * persistent index is stored in directory entries.
3030 * Special cases: 0 = .
3031 * 1 = ..
3032 * -1 = End of directory
3033 */
3038 /*
3039 * NFSv4 reserves cookies 1 and 2 for . and .. so the value
3040 * we return to the vfs is one greater than the one we use
3041 * internally.
3042 */
3044 dir_index--;
3051 /* Stale position. Directory has shrunk */
3054 }
3055 repeat:
3060 }
3066 }
3071 }
3073 }
3080 }
3086 }
3089 /*
3090 * self "."
3091 */
3095 }
3096 /*
3097 * parent ".."
3098 */
3103 /*
3104 * Find first entry of left-most leaf
3105 */
3109 }
3115 }
3117 /*
3118 * Legacy filesystem - OS/2 & Linux JFS < 0.3.6
3119 *
3120 * pn = 0; index = 1: First entry "."
3121 * pn = 0; index = 2: Second entry ".."
3122 * pn > 0: Real entries, pn=1 -> leftmost page
3123 * pn = index = -1: No more entries
3124 */
3127 /* build "." entry */
3133 }
3137 /* build ".." entry */
3142 }
3146 }
3151 }
3155 rc);
3158 }
3159 /* get start leaf page and index */
3162 /* offset beyond directory eof ? */
3166 }
3167 }
3175 }
3189 /* DBCS codepages could overrun dirent_buf */
3193 }
3202 /*
3203 * d->index should always be valid, but it
3204 * isn't. fsck.jfs doesn't create the
3205 * directory index for the lost+found
3206 * directory. Rather than let it go,
3207 * we can try to fix it.
3208 */
3214 /*
3215 * setting overflow and setting
3216 * index to i will cause the
3217 * same page to be processed
3218 * again starting here
3219 */
3223 }
3225 }
3226 /*
3227 * We add 1 to the index because we may
3228 * use a value of 2 internally, and NFSv4
3229 * doesn't like that.
3230 */
3235 }
3237 /* copy the name of head/only segment */
3239 codepage);
3242 /* copy name in the additional segment(s) */
3248 /* Sanity Check */
3254 i);
3256 }
3263 }
3265 jfs_dirents++;
3267 skip_one:
3270 }
3273 /* Point to next leaf page */
3279 /* update offset (pn:index) for new page */
3283 }
3284 }
3286 }
3288 /* unpin previous leaf page */
3299 }
3304 }
3309 }
3315 }
3316 }
3318 out:
3322 }
3325 /*
3326 * dtReadFirst()
3327 *
3328 * function: get the leftmost page of the directory
3329 */
3331 {
3333 s64 bn;
3343 /*
3344 * descend leftmost path of the tree
3345 *
3346 * by convention, root bn = 0.
3347 */
3353 /*
3354 * leftmost leaf page
3355 */
3357 /* return leftmost entry */
3364 }
3366 /*
3367 * descend down to leftmost child page
3368 */
3374 }
3375 /* push (bn, index) of the parent page/entry */
3378 /* get the leftmost entry */
3382 /* get the child page block address */
3386 /* unpin the parent page */
3388 }
3389 }
3392 /*
3393 * dtReadNext()
3394 *
3395 * function: get the page of the specified offset (pn:index)
3396 *
3397 * return: if (offset > eof), bn = -1;
3398 *
3399 * note: if index > nextindex of the target leaf page,
3400 * start with 1st entry of next leaf page;
3401 */
3404 {
3407 s16 pn;
3408 s16 index;
3409 s32 unused;
3411 s64 bn;
3420 /*
3421 * get leftmost leaf page pinned
3422 */
3426 /* get leaf page */
3429 /* get the start offset (pn:index) */
3433 /* start at leftmost page ? */
3435 /* offset beyond eof ? */
3442 }
3444 /* start with 1st entry of next leaf page */
3448 }
3450 /* start at non-leftmost page: scan parent pages for large pn */
3454 }
3456 /* start after next leaf page ? */
3460 /* get leaf page pn = 1 */
3461 a:
3464 /* unpin leaf page */
3467 /* offset beyond eof ? */
3471 }
3475 /*
3476 * scan last internal page level to get target leaf page
3477 */
3478 b:
3479 /* unpin leftmost leaf page */
3482 /* get left most parent page */
3490 /* scan parent pages at last internal page level */
3494 /* get next parent page address */
3497 /* unpin current parent page */
3500 /* offset beyond eof ? */
3504 }
3506 /* get next parent page */
3511 /* update parent page stack frame */
3513 }
3515 /* get leaf page address */
3520 /* unpin parent page */
3523 /*
3524 * get target leaf page
3525 */
3526 c:
3531 /*
3532 * leaf page has been completed:
3533 * start with 1st entry of next leaf page
3534 */
3538 /* unpin leaf page */
3541 /* offset beyond eof ? */
3545 }
3547 /* get next leaf page */
3552 /* start with 1st entry of next leaf page */
3555 }
3557 out:
3558 /* return target leaf page pinned */
3565 }
3568 /*
3569 * dtCompare()
3570 *
3571 * function: compare search key with an internal entry
3572 *
3573 * return:
3574 * < 0 if k is < record
3575 * = 0 if k is = record
3576 * > 0 if k is > record
3577 */
3588 /*
3589 * force the left-most key on internal pages, at any level of
3590 * the tree, to be less than any search key.
3591 * this obviates having to update the leftmost key on an internal
3592 * page when the user inserts a new key in the tree smaller than
3593 * anything that has been stored.
3594 *
3595 * (? if/when dtSearch() narrows down to 1st entry (index = 0),
3596 * at any internal page at any level of the tree,
3597 * it descends to child of the entry anyway -
3598 * ? make the entry as min size dummy entry)
3599 *
3600 * if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & BT_LEAF))
3601 * return (1);
3602 */
3613 /* compare with head/only segment */
3621 /* compare with additional segment(s) */
3624 /* compare with next name segment */
3636 }
3639 }
3644 /*
3645 * ciCompare()
3646 *
3647 * function: compare search key with an (leaf/internal) entry
3648 *
3649 * return:
3650 * < 0 if k is < record
3651 * = 0 if k is = record
3652 * > 0 if k is > record
3653 */
3658 {
3667 /*
3668 * force the left-most key on internal pages, at any level of
3669 * the tree, to be less than any search key.
3670 * this obviates having to update the leftmost key on an internal
3671 * page when the user inserts a new key in the tree smaller than
3672 * anything that has been stored.
3673 *
3674 * (? if/when dtSearch() narrows down to 1st entry (index = 0),
3675 * at any internal page at any level of the tree,
3676 * it descends to child of the entry anyway -
3677 * ? make the entry as min size dummy entry)
3678 *
3679 * if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & BT_LEAF))
3680 * return (1);
3681 */
3686 /*
3687 * leaf page entry
3688 */
3696 else
3698 }
3699 /*
3700 * internal page entry
3701 */
3708 }
3710 /* compare with head/only segment */
3713 /* only uppercase if case-insensitive support is on */
3716 else
3720 }
3725 /* compare with additional segment(s) */
3727 /* compare with next name segment */
3733 /* only uppercase if case-insensitive support is on */
3736 else
3741 }
3746 }
3749 }
3752 /*
3753 * ciGetLeafPrefixKey()
3754 *
3755 * function: compute prefix of suffix compression
3756 * from two adjacent leaf entries
3757 * across page boundary
3758 *
3759 * return: non-zero on error
3760 *
3761 */
3764 {
3771 GFP_KERNEL);
3776 GFP_KERNEL);
3780 }
3782 /* get left and right key */
3796 /* compute prefix */
3806 }
3807 }
3809 /* l->namlen <= r->namlen since l <= r */
3816 free_names:
3820 }
3824 /*
3825 * dtGetKey()
3826 *
3827 * function: get key of the entry
3828 */
3831 {
3841 /* get entry */
3851 else
3859 }
3864 /*
3865 * move head/only segment
3866 */
3869 /*
3870 * move additional segment(s)
3871 */
3873 /* get next segment */
3881 }
3882 }
3885 /*
3886 * dtInsertEntry()
3887 *
3888 * function: allocate free slot(s) and
3889 * write a leaf/internal entry
3890 *
3891 * return: entry slot index
3892 */
3895 {
3913 /* allocate a free slot */
3919 /* open new linelock */
3926 /* write head/only segment */
3950 }
3957 /* write additional segment(s) */
3961 /* get free slot */
3967 /* is next slot contiguous ? */
3969 /* close current linelock */
3973 /* open new linelock */
3975 lv++;
3979 }
3983 }
3989 n++;
3992 }
3994 /* close current linelock */
4000 /* terminate last/only segment */
4002 /* single segment entry */
4005 else
4008 /* multi-segment entry */
4011 /* if insert into middle, shift right succeeding entries in stbl */
4018 s64 lblock;
4020 /*
4021 * Need to update slot number for entries that moved
4022 * in the stbl
4023 */
4030 }
4033 }
4034 }
4038 /* advance next available entry index of stbl */
4040 }
4043 /*
4044 * dtMoveEntry()
4045 *
4046 * function: move entries from split/left page to new/right page
4047 *
4048 * nextindex of dst page and freelist/freecnt of both pages
4049 * are updated.
4050 */
4054 {
4074 /* linelock destination entry slot */
4078 /* linelock source entry slot */
4083 /*
4084 * move entries
4085 */
4091 /* is next slot contiguous ? */
4093 /* close current linelock */
4097 /* open new linelock */
4099 slv++;
4103 }
4107 }
4109 /*
4110 * move head/only segment of an entry
4111 */
4112 /* get dst slot */
4115 /* get src slot and move */
4118 /* get source entry */
4133 /* update dst head/only segment next field */
4134 dsi++;
4145 dsi++;
4147 }
4149 /* free src head/only segment */
4154 ns++;
4155 nd++;
4158 /*
4159 * move additional segment(s) of the entry
4160 */
4163 /* is next slot contiguous ? */
4165 /* close current linelock */
4169 /* open new linelock */
4171 slv++;
4173 sdtlck =
4177 }
4181 }
4183 /* get next source segment */
4186 /* get next destination free slot */
4187 d++;
4192 ns++;
4193 nd++;
4196 dsi++;
4199 /* free source segment */
4208 /* terminate dst last/only segment */
4210 /* single segment entry */
4213 else
4216 /* multi-segment entry */
4220 /* close current linelock */
4229 /* update source header */
4233 /* update destination header */
4238 }
4241 /*
4242 * dtDeleteEntry()
4243 *
4244 * function: free a (leaf/internal) entry
4245 *
4246 * log freelist header, stbl, and each segment slot of entry
4247 * (even though last/only segment next field is modified,
4248 * physical image logging requires all segment slots of
4249 * the entry logged to avoid applying previous updates
4250 * to the same slots)
4251 */
4253 {
4262 /* get free entry slot index */
4266 /* open new linelock */
4273 /* get the head/only segment */
4277 else
4285 /* find the last/only segment */
4287 /* is next slot contiguous ? */
4289 /* close current linelock */
4293 /* open new linelock */
4295 lv++;
4299 }
4303 }
4305 n++;
4307 freecnt++;
4312 }
4314 /* close current linelock */
4320 /* update freelist */
4325 /* if delete from middle,
4326 * shift left the succedding entries in the stbl
4327 */
4333 }
4336 /*
4337 * dtTruncateEntry()
4338 *
4339 * function: truncate a (leaf/internal) entry
4340 *
4341 * log freelist header, stbl, and each segment slot of entry
4342 * (even though last/only segment next field is modified,
4343 * physical image logging requires all segment slots of
4344 * the entry logged to avoid applying previous updates
4345 * to the same slots)
4346 */
4348 {
4357 /* get free entry slot index */
4361 /* open new linelock */
4368 /* get the head/only segment */
4380 /* find the last/only segment */
4382 /* is next slot contiguous ? */
4384 /* close current linelock */
4388 /* open new linelock */
4390 lv++;
4394 }
4398 }
4400 n++;
4402 freecnt++;
4407 }
4409 /* close current linelock */
4415 /* update freelist */
4421 }
4424 /*
4425 * dtLinelockFreelist()
4426 */
4430 {
4438 /* get free entry slot index */
4441 /* open new linelock */
4454 /* find the last/only segment */
4456 /* is next slot contiguous ? */
4458 /* close current linelock */
4462 /* open new linelock */
4464 lv++;
4468 }
4472 }
4474 n++;
4479 }
4481 /* close current linelock */
4486 }
4489 /*
4490 * NAME: dtModify
4491 *
4492 * FUNCTION: Modify the inode number part of a directory entry
4493 *
4494 * PARAMETERS:
4495 * tid - Transaction id
4496 * ip - Inode of parent directory
4497 * key - Name of entry to be modified
4498 * orig_ino - Original inode number expected in entry
4499 * new_ino - New inode number to put into entry
4500 * flag - JFS_RENAME
4501 *
4502 * RETURNS:
4503 * -ESTALE - If entry found does not match orig_ino passed in
4504 * -ENOENT - If no entry can be found to match key
4505 * 0 - If successfully modified entry
4506 */
4509 {
4511 s64 bn;
4523 /*
4524 * search for the entry to modify:
4525 *
4526 * dtSearch() returns (leaf page pinned, index at which to modify).
4527 */
4531 /* retrieve search result */
4535 /*
4536 * acquire a transaction lock on the leaf page of named entry
4537 */
4541 /* get slot index of the entry */
4545 /* linelock entry */
4552 /* get the head/only segment */
4555 /* substitute the inode number of the entry */
4558 /* unpin the leaf page */
4562 }