patch-2.4.20 linux-2.4.20/fs/jfs/jfs_dmap.c
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- Lines: 4193
- Date:
Thu Nov 28 15:53:15 2002
- Orig file:
linux-2.4.19/fs/jfs/jfs_dmap.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -urN linux-2.4.19/fs/jfs/jfs_dmap.c linux-2.4.20/fs/jfs/jfs_dmap.c
@@ -0,0 +1,4192 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2000-2002
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/fs.h>
+#include "jfs_incore.h"
+#include "jfs_dmap.h"
+#include "jfs_imap.h"
+#include "jfs_lock.h"
+#include "jfs_metapage.h"
+#include "jfs_debug.h"
+
+/*
+ * Debug code for double-checking block map
+ */
+/* #define _JFS_DEBUG_DMAP 1 */
+
+#ifdef _JFS_DEBUG_DMAP
+#define DBINITMAP(size,ipbmap,results) \
+ DBinitmap(size,ipbmap,results)
+#define DBALLOC(dbmap,mapsize,blkno,nblocks) \
+ DBAlloc(dbmap,mapsize,blkno,nblocks)
+#define DBFREE(dbmap,mapsize,blkno,nblocks) \
+ DBFree(dbmap,mapsize,blkno,nblocks)
+#define DBALLOCCK(dbmap,mapsize,blkno,nblocks) \
+ DBAllocCK(dbmap,mapsize,blkno,nblocks)
+#define DBFREECK(dbmap,mapsize,blkno,nblocks) \
+ DBFreeCK(dbmap,mapsize,blkno,nblocks)
+
+static void DBinitmap(s64, struct inode *, u32 **);
+static void DBAlloc(uint *, s64, s64, s64);
+static void DBFree(uint *, s64, s64, s64);
+static void DBAllocCK(uint *, s64, s64, s64);
+static void DBFreeCK(uint *, s64, s64, s64);
+#else
+#define DBINITMAP(size,ipbmap,results)
+#define DBALLOC(dbmap, mapsize, blkno, nblocks)
+#define DBFREE(dbmap, mapsize, blkno, nblocks)
+#define DBALLOCCK(dbmap, mapsize, blkno, nblocks)
+#define DBFREECK(dbmap, mapsize, blkno, nblocks)
+#endif /* _JFS_DEBUG_DMAP */
+
+/*
+ * SERIALIZATION of the Block Allocation Map.
+ *
+ * the working state of the block allocation map is accessed in
+ * two directions:
+ *
+ * 1) allocation and free requests that start at the dmap
+ * level and move up through the dmap control pages (i.e.
+ * the vast majority of requests).
+ *
+ * 2) allocation requests that start at dmap control page
+ * level and work down towards the dmaps.
+ *
+ * the serialization scheme used here is as follows.
+ *
+ * requests which start at the bottom are serialized against each
+ * other through buffers and each requests holds onto its buffers
+ * as it works it way up from a single dmap to the required level
+ * of dmap control page.
+ * requests that start at the top are serialized against each other
+ * and request that start from the bottom by the multiple read/single
+ * write inode lock of the bmap inode. requests starting at the top
+ * take this lock in write mode while request starting at the bottom
+ * take the lock in read mode. a single top-down request may proceed
+ * exclusively while multiple bottoms-up requests may proceed
+ * simultaneously (under the protection of busy buffers).
+ *
+ * in addition to information found in dmaps and dmap control pages,
+ * the working state of the block allocation map also includes read/
+ * write information maintained in the bmap descriptor (i.e. total
+ * free block count, allocation group level free block counts).
+ * a single exclusive lock (BMAP_LOCK) is used to guard this information
+ * in the face of multiple-bottoms up requests.
+ * (lock ordering: IREAD_LOCK, BMAP_LOCK);
+ *
+ * accesses to the persistent state of the block allocation map (limited
+ * to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
+ */
+
+#define BMAP_LOCK_INIT(bmp) init_MUTEX(&bmp->db_bmaplock)
+#define BMAP_LOCK(bmp) down(&bmp->db_bmaplock)
+#define BMAP_UNLOCK(bmp) up(&bmp->db_bmaplock)
+
+/*
+ * forward references
+ */
+static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks);
+static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
+static void dbBackSplit(dmtree_t * tp, int leafno);
+static void dbJoin(dmtree_t * tp, int leafno, int newval);
+static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
+static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
+ int level);
+static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
+static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks);
+static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks,
+ int l2nb, s64 * results);
+static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks);
+static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
+ int l2nb,
+ s64 * results);
+static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
+ s64 * results);
+static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
+ s64 * results);
+int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
+static int dbFindBits(u32 word, int l2nb);
+static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
+static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
+static void dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks);
+static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks);
+static int dbMaxBud(u8 * cp);
+s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
+int blkstol2(s64 nb);
+void fsDirty(void);
+
+int cntlz(u32 value);
+int cnttz(u32 word);
+
+static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks);
+static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
+static int dbInitDmapTree(struct dmap * dp);
+static int dbInitTree(struct dmaptree * dtp);
+static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
+static int dbGetL2AGSize(s64 nblocks);
+
+/*
+ * buddy table
+ *
+ * table used for determining buddy sizes within characters of
+ * dmap bitmap words. the characters themselves serve as indexes
+ * into the table, with the table elements yielding the maximum
+ * binary buddy of free bits within the character.
+ */
+signed char budtab[256] = {
+ 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
+ 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
+ 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
+ 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
+ 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
+ 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
+ 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
+ 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
+ 2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
+};
+
+
+/*
+ * NAME: dbMount()
+ *
+ * FUNCTION: initializate the block allocation map.
+ *
+ * memory is allocated for the in-core bmap descriptor and
+ * the in-core descriptor is initialized from disk.
+ *
+ * PARAMETERS:
+ * ipbmap - pointer to in-core inode for the block map.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOMEM - insufficient memory
+ * EIO - i/o error
+ */
+int dbMount(struct inode *ipbmap)
+{
+ struct bmap *bmp;
+ struct dbmap *dbmp_le;
+ struct metapage *mp;
+ int i;
+
+ /*
+ * allocate/initialize the in-memory bmap descriptor
+ */
+ /* allocate memory for the in-memory bmap descriptor */
+ bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
+ if (bmp == NULL)
+ return (ENOMEM);
+
+ /* read the on-disk bmap descriptor. */
+ mp = read_metapage(ipbmap,
+ BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
+ PSIZE, 0);
+ if (mp == NULL) {
+ kfree(bmp);
+ return (EIO);
+ }
+
+ /* copy the on-disk bmap descriptor to its in-memory version. */
+ dbmp_le = (struct dbmap *) mp->data;
+ bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
+ bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
+ bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
+ bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
+ bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
+ bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
+ bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
+ bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
+ bmp->db_agheigth = le32_to_cpu(dbmp_le->dn_agheigth);
+ bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
+ bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
+ bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
+ for (i = 0; i < MAXAG; i++)
+ bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
+ bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
+ bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
+
+ /* release the buffer. */
+ release_metapage(mp);
+
+ /* bind the bmap inode and the bmap descriptor to each other. */
+ bmp->db_ipbmap = ipbmap;
+ JFS_SBI(ipbmap->i_sb)->bmap = bmp;
+
+ memset(bmp->db_active, 0, sizeof(bmp->db_active));
+ DBINITMAP(bmp->db_mapsize, ipbmap, &bmp->db_DBmap);
+
+ /*
+ * allocate/initialize the bmap lock
+ */
+ BMAP_LOCK_INIT(bmp);
+
+ return (0);
+}
+
+
+/*
+ * NAME: dbUnmount()
+ *
+ * FUNCTION: terminate the block allocation map in preparation for
+ * file system unmount.
+ *
+ * the in-core bmap descriptor is written to disk and
+ * the memory for this descriptor is freed.
+ *
+ * PARAMETERS:
+ * ipbmap - pointer to in-core inode for the block map.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * EIO - i/o error
+ */
+int dbUnmount(struct inode *ipbmap, int mounterror)
+{
+ struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
+ int i;
+
+ if (!(mounterror || isReadOnly(ipbmap)))
+ dbSync(ipbmap);
+
+ /*
+ * Invalidate the page cache buffers
+ */
+ truncate_inode_pages(ipbmap->i_mapping, 0);
+
+ /*
+ * Sanity Check
+ */
+ for (i = 0; i < bmp->db_numag; i++)
+ if (atomic_read(&bmp->db_active[i]))
+ printk(KERN_ERR "dbUnmount: db_active[%d] = %d\n",
+ i, atomic_read(&bmp->db_active[i]));
+
+ /* free the memory for the in-memory bmap. */
+ kfree(bmp);
+
+ return (0);
+}
+
+/*
+ * dbSync()
+ */
+int dbSync(struct inode *ipbmap)
+{
+ struct dbmap *dbmp_le;
+ struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
+ struct metapage *mp;
+ int i;
+
+ /*
+ * write bmap global control page
+ */
+ /* get the buffer for the on-disk bmap descriptor. */
+ mp = read_metapage(ipbmap,
+ BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
+ PSIZE, 0);
+ if (mp == NULL) {
+ jERROR(1,("dbSync: read_metapage failed!\n"));
+ return (EIO);
+ }
+ /* copy the in-memory version of the bmap to the on-disk version */
+ dbmp_le = (struct dbmap *) mp->data;
+ dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
+ dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
+ dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
+ dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
+ dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
+ dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
+ dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
+ dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
+ dbmp_le->dn_agheigth = cpu_to_le32(bmp->db_agheigth);
+ dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
+ dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
+ dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
+ for (i = 0; i < MAXAG; i++)
+ dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
+ dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
+ dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
+
+ /* write the buffer */
+ write_metapage(mp);
+
+ /*
+ * write out dirty pages of bmap
+ */
+ fsync_inode_data_buffers(ipbmap);
+
+ ipbmap->i_state |= I_DIRTY;
+ diWriteSpecial(ipbmap, 0);
+
+ return (0);
+}
+
+
+/*
+ * NAME: dbFree()
+ *
+ * FUNCTION: free the specified block range from the working block
+ * allocation map.
+ *
+ * the blocks will be free from the working map one dmap
+ * at a time.
+ *
+ * PARAMETERS:
+ * ip - pointer to in-core inode;
+ * blkno - starting block number to be freed.
+ * nblocks - number of blocks to be freed.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * EIO - i/o error
+ */
+int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
+{
+ struct metapage *mp;
+ struct dmap *dp;
+ int nb, rc;
+ s64 lblkno, rem;
+ struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
+ struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
+
+ IREAD_LOCK(ipbmap);
+
+ /* block to be freed better be within the mapsize. */
+ assert(blkno + nblocks <= bmp->db_mapsize);
+
+ /*
+ * free the blocks a dmap at a time.
+ */
+ mp = NULL;
+ for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
+ /* release previous dmap if any */
+ if (mp) {
+ write_metapage(mp);
+ }
+
+ /* get the buffer for the current dmap. */
+ lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
+ mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL) {
+ IREAD_UNLOCK(ipbmap);
+ return (EIO);
+ }
+ dp = (struct dmap *) mp->data;
+
+ /* determine the number of blocks to be freed from
+ * this dmap.
+ */
+ nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
+
+ DBALLOCCK(bmp->db_DBmap, bmp->db_mapsize, blkno, nb);
+
+ /* free the blocks. */
+ if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
+ release_metapage(mp);
+ IREAD_UNLOCK(ipbmap);
+ return (rc);
+ }
+
+ DBFREE(bmp->db_DBmap, bmp->db_mapsize, blkno, nb);
+ }
+
+ /* write the last buffer. */
+ write_metapage(mp);
+
+ IREAD_UNLOCK(ipbmap);
+
+ return (0);
+}
+
+
+/*
+ * NAME: dbUpdatePMap()
+ *
+ * FUNCTION: update the allocation state (free or allocate) of the
+ * specified block range in the persistent block allocation map.
+ *
+ * the blocks will be updated in the persistent map one
+ * dmap at a time.
+ *
+ * PARAMETERS:
+ * ipbmap - pointer to in-core inode for the block map.
+ * free - TRUE if block range is to be freed from the persistent
+ * map; FALSE if it is to be allocated.
+ * blkno - starting block number of the range.
+ * nblocks - number of contiguous blocks in the range.
+ * tblk - transaction block;
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * EIO - i/o error
+ */
+int
+dbUpdatePMap(struct inode *ipbmap,
+ int free, s64 blkno, s64 nblocks, struct tblock * tblk)
+{
+ int nblks, dbitno, wbitno, rbits;
+ int word, nbits, nwords;
+ struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
+ s64 lblkno, rem, lastlblkno;
+ u32 mask;
+ struct dmap *dp;
+ struct metapage *mp;
+ struct jfs_log *log;
+ int lsn, difft, diffp;
+
+ /* the blocks better be within the mapsize. */
+ assert(blkno + nblocks <= bmp->db_mapsize);
+
+ /* compute delta of transaction lsn from log syncpt */
+ lsn = tblk->lsn;
+ log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
+ logdiff(difft, lsn, log);
+
+ /*
+ * update the block state a dmap at a time.
+ */
+ mp = NULL;
+ lastlblkno = 0;
+ for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
+ /* get the buffer for the current dmap. */
+ lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
+ if (lblkno != lastlblkno) {
+ if (mp) {
+ write_metapage(mp);
+ }
+
+ mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
+ 0);
+ if (mp == NULL)
+ return (EIO);
+ }
+ dp = (struct dmap *) mp->data;
+
+ /* determine the bit number and word within the dmap of
+ * the starting block. also determine how many blocks
+ * are to be updated within this dmap.
+ */
+ dbitno = blkno & (BPERDMAP - 1);
+ word = dbitno >> L2DBWORD;
+ nblks = min(rem, (s64)BPERDMAP - dbitno);
+
+ /* update the bits of the dmap words. the first and last
+ * words may only have a subset of their bits updated. if
+ * this is the case, we'll work against that word (i.e.
+ * partial first and/or last) only in a single pass. a
+ * single pass will also be used to update all words that
+ * are to have all their bits updated.
+ */
+ for (rbits = nblks; rbits > 0;
+ rbits -= nbits, dbitno += nbits) {
+ /* determine the bit number within the word and
+ * the number of bits within the word.
+ */
+ wbitno = dbitno & (DBWORD - 1);
+ nbits = min(rbits, DBWORD - wbitno);
+
+ /* check if only part of the word is to be updated. */
+ if (nbits < DBWORD) {
+ /* update (free or allocate) the bits
+ * in this word.
+ */
+ mask =
+ (ONES << (DBWORD - nbits) >> wbitno);
+ if (free)
+ dp->pmap[word] &=
+ cpu_to_le32(~mask);
+ else
+ dp->pmap[word] |=
+ cpu_to_le32(mask);
+
+ word += 1;
+ } else {
+ /* one or more words are to have all
+ * their bits updated. determine how
+ * many words and how many bits.
+ */
+ nwords = rbits >> L2DBWORD;
+ nbits = nwords << L2DBWORD;
+
+ /* update (free or allocate) the bits
+ * in these words.
+ */
+ if (free)
+ memset(&dp->pmap[word], 0,
+ nwords * 4);
+ else
+ memset(&dp->pmap[word], (int) ONES,
+ nwords * 4);
+
+ word += nwords;
+ }
+ }
+
+ /*
+ * update dmap lsn
+ */
+ if (lblkno == lastlblkno)
+ continue;
+
+ lastlblkno = lblkno;
+
+ if (mp->lsn != 0) {
+ /* inherit older/smaller lsn */
+ logdiff(diffp, mp->lsn, log);
+ if (difft < diffp) {
+ mp->lsn = lsn;
+
+ /* move bp after tblock in logsync list */
+ LOGSYNC_LOCK(log);
+ list_del(&mp->synclist);
+ list_add(&mp->synclist, &tblk->synclist);
+ LOGSYNC_UNLOCK(log);
+ }
+
+ /* inherit younger/larger clsn */
+ LOGSYNC_LOCK(log);
+ logdiff(difft, tblk->clsn, log);
+ logdiff(diffp, mp->clsn, log);
+ if (difft > diffp)
+ mp->clsn = tblk->clsn;
+ LOGSYNC_UNLOCK(log);
+ } else {
+ mp->log = log;
+ mp->lsn = lsn;
+
+ /* insert bp after tblock in logsync list */
+ LOGSYNC_LOCK(log);
+
+ log->count++;
+ list_add(&mp->synclist, &tblk->synclist);
+
+ mp->clsn = tblk->clsn;
+ LOGSYNC_UNLOCK(log);
+ }
+ }
+
+ /* write the last buffer. */
+ if (mp) {
+ write_metapage(mp);
+ }
+
+ return (0);
+}
+
+
+/*
+ * NAME: dbNextAG()
+ *
+ * FUNCTION: find the preferred allocation group for new allocations.
+ *
+ * Within the allocation groups, we maintain a preferred
+ * allocation group which consists of a group with at least
+ * average free space. It is the preferred group that we target
+ * new inode allocation towards. The tie-in between inode
+ * allocation and block allocation occurs as we allocate the
+ * first (data) block of an inode and specify the inode (block)
+ * as the allocation hint for this block.
+ *
+ * We try to avoid having more than one open file growing in
+ * an allocation group, as this will lead to fragmentation.
+ * This differs from the old OS/2 method of trying to keep
+ * empty ags around for large allocations.
+ *
+ * PARAMETERS:
+ * ipbmap - pointer to in-core inode for the block map.
+ *
+ * RETURN VALUES:
+ * the preferred allocation group number.
+ */
+int dbNextAG(struct inode *ipbmap)
+{
+ s64 avgfree;
+ int agpref;
+ s64 hwm = 0;
+ int i;
+ int next_best = -1;
+ struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
+
+ BMAP_LOCK(bmp);
+
+ /* determine the average number of free blocks within the ags. */
+ avgfree = (u32)bmp->db_nfree / bmp->db_numag;
+
+ /*
+ * if the current preferred ag does not have an active allocator
+ * and has at least average freespace, return it
+ */
+ agpref = bmp->db_agpref;
+ if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
+ (bmp->db_agfree[agpref] >= avgfree))
+ goto unlock;
+
+ /* From the last preferred ag, find the next one with at least
+ * average free space.
+ */
+ for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
+ if (agpref == bmp->db_numag)
+ agpref = 0;
+
+ if (atomic_read(&bmp->db_active[agpref]))
+ /* open file is currently growing in this ag */
+ continue;
+ if (bmp->db_agfree[agpref] >= avgfree) {
+ /* Return this one */
+ bmp->db_agpref = agpref;
+ goto unlock;
+ } else if (bmp->db_agfree[agpref] > hwm) {
+ /* Less than avg. freespace, but best so far */
+ hwm = bmp->db_agfree[agpref];
+ next_best = agpref;
+ }
+ }
+
+ /*
+ * If no inactive ag was found with average freespace, use the
+ * next best
+ */
+ if (next_best != -1)
+ bmp->db_agpref = next_best;
+ /* else leave db_agpref unchanged */
+unlock:
+ BMAP_UNLOCK(bmp);
+
+ /* return the preferred group.
+ */
+ return (bmp->db_agpref);
+}
+
+/*
+ * NAME: dbAlloc()
+ *
+ * FUNCTION: attempt to allocate a specified number of contiguous free
+ * blocks from the working allocation block map.
+ *
+ * the block allocation policy uses hints and a multi-step
+ * approach.
+ *
+ * for allocation requests smaller than the number of blocks
+ * per dmap, we first try to allocate the new blocks
+ * immediately following the hint. if these blocks are not
+ * available, we try to allocate blocks near the hint. if
+ * no blocks near the hint are available, we next try to
+ * allocate within the same dmap as contains the hint.
+ *
+ * if no blocks are available in the dmap or the allocation
+ * request is larger than the dmap size, we try to allocate
+ * within the same allocation group as contains the hint. if
+ * this does not succeed, we finally try to allocate anywhere
+ * within the aggregate.
+ *
+ * we also try to allocate anywhere within the aggregate for
+ * for allocation requests larger than the allocation group
+ * size or requests that specify no hint value.
+ *
+ * PARAMETERS:
+ * ip - pointer to in-core inode;
+ * hint - allocation hint.
+ * nblocks - number of contiguous blocks in the range.
+ * results - on successful return, set to the starting block number
+ * of the newly allocated contiguous range.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ */
+int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
+{
+ int rc, agno;
+ struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
+ struct bmap *bmp;
+ struct metapage *mp;
+ s64 lblkno, blkno;
+ struct dmap *dp;
+ int l2nb;
+ s64 mapSize;
+ int writers;
+
+ /* assert that nblocks is valid */
+ assert(nblocks > 0);
+
+#ifdef _STILL_TO_PORT
+ /* DASD limit check F226941 */
+ if (OVER_LIMIT(ip, nblocks))
+ return ENOSPC;
+#endif /* _STILL_TO_PORT */
+
+ /* get the log2 number of blocks to be allocated.
+ * if the number of blocks is not a log2 multiple,
+ * it will be rounded up to the next log2 multiple.
+ */
+ l2nb = BLKSTOL2(nblocks);
+
+ bmp = JFS_SBI(ip->i_sb)->bmap;
+
+//retry: /* serialize w.r.t.extendfs() */
+ mapSize = bmp->db_mapsize;
+
+ /* the hint should be within the map */
+ assert(hint < mapSize);
+
+ /* if the number of blocks to be allocated is greater than the
+ * allocation group size, try to allocate anywhere.
+ */
+ if (l2nb > bmp->db_agl2size) {
+ IWRITE_LOCK(ipbmap);
+
+ rc = dbAllocAny(bmp, nblocks, l2nb, results);
+ if (rc == 0) {
+ DBALLOC(bmp->db_DBmap, bmp->db_mapsize, *results,
+ nblocks);
+ }
+
+ goto write_unlock;
+ }
+
+ /*
+ * If no hint, let dbNextAG recommend an allocation group
+ */
+ if (hint == 0)
+ goto pref_ag;
+
+ /* we would like to allocate close to the hint. adjust the
+ * hint to the block following the hint since the allocators
+ * will start looking for free space starting at this point.
+ */
+ blkno = hint + 1;
+
+ if (blkno >= bmp->db_mapsize)
+ goto pref_ag;
+
+ agno = blkno >> bmp->db_agl2size;
+
+ /* check if blkno crosses over into a new allocation group.
+ * if so, check if we should allow allocations within this
+ * allocation group.
+ */
+ if ((blkno & (bmp->db_agsize - 1)) == 0)
+ /* check if the AG is currenly being written to.
+ * if so, call dbNextAG() to find a non-busy
+ * AG with sufficient free space.
+ */
+ if (atomic_read(&bmp->db_active[agno]))
+ goto pref_ag;
+
+ /* check if the allocation request size can be satisfied from a
+ * single dmap. if so, try to allocate from the dmap containing
+ * the hint using a tiered strategy.
+ */
+ if (nblocks <= BPERDMAP) {
+ IREAD_LOCK(ipbmap);
+
+ /* get the buffer for the dmap containing the hint.
+ */
+ rc = EIO;
+ lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
+ mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL)
+ goto read_unlock;
+
+ dp = (struct dmap *) mp->data;
+
+ /* first, try to satisfy the allocation request with the
+ * blocks beginning at the hint.
+ */
+ if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
+ != ENOSPC) {
+ if (rc == 0) {
+ *results = blkno;
+ DBALLOC(bmp->db_DBmap, bmp->db_mapsize,
+ *results, nblocks);
+ mark_metapage_dirty(mp);
+ }
+
+ release_metapage(mp);
+ goto read_unlock;
+ }
+
+ writers = atomic_read(&bmp->db_active[agno]);
+ if ((writers > 1) ||
+ ((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
+ /*
+ * Someone else is writing in this allocation
+ * group. To avoid fragmenting, try another ag
+ */
+ release_metapage(mp);
+ IREAD_UNLOCK(ipbmap);
+ goto pref_ag;
+ }
+
+ /* next, try to satisfy the allocation request with blocks
+ * near the hint.
+ */
+ if ((rc =
+ dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
+ != ENOSPC) {
+ if (rc == 0) {
+ DBALLOC(bmp->db_DBmap, bmp->db_mapsize,
+ *results, nblocks);
+ mark_metapage_dirty(mp);
+ }
+
+ release_metapage(mp);
+ goto read_unlock;
+ }
+
+ /* try to satisfy the allocation request with blocks within
+ * the same dmap as the hint.
+ */
+ if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
+ != ENOSPC) {
+ if (rc == 0) {
+ DBALLOC(bmp->db_DBmap, bmp->db_mapsize,
+ *results, nblocks);
+ mark_metapage_dirty(mp);
+ }
+
+ release_metapage(mp);
+ goto read_unlock;
+ }
+
+ release_metapage(mp);
+ IREAD_UNLOCK(ipbmap);
+ }
+
+ /* try to satisfy the allocation request with blocks within
+ * the same allocation group as the hint.
+ */
+ IWRITE_LOCK(ipbmap);
+ if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results))
+ != ENOSPC) {
+ if (rc == 0)
+ DBALLOC(bmp->db_DBmap, bmp->db_mapsize,
+ *results, nblocks);
+ goto write_unlock;
+ }
+ IWRITE_UNLOCK(ipbmap);
+
+
+ pref_ag:
+ /*
+ * Let dbNextAG recommend a preferred allocation group
+ */
+ agno = dbNextAG(ipbmap);
+ IWRITE_LOCK(ipbmap);
+
+ /* Try to allocate within this allocation group. if that fails, try to
+ * allocate anywhere in the map.
+ */
+ if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == ENOSPC)
+ rc = dbAllocAny(bmp, nblocks, l2nb, results);
+ if (rc == 0) {
+ DBALLOC(bmp->db_DBmap, bmp->db_mapsize, *results, nblocks);
+ }
+
+ write_unlock:
+ IWRITE_UNLOCK(ipbmap);
+
+ return (rc);
+
+ read_unlock:
+ IREAD_UNLOCK(ipbmap);
+
+ return (rc);
+}
+
+
+/*
+ * NAME: dbAllocExact()
+ *
+ * FUNCTION: try to allocate the requested extent;
+ *
+ * PARAMETERS:
+ * ip - pointer to in-core inode;
+ * blkno - extent address;
+ * nblocks - extent length;
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ */
+int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
+{
+ int rc;
+ struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
+ struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
+ struct dmap *dp;
+ s64 lblkno;
+ struct metapage *mp;
+
+ IREAD_LOCK(ipbmap);
+
+ /*
+ * validate extent request:
+ *
+ * note: defragfs policy:
+ * max 64 blocks will be moved.
+ * allocation request size must be satisfied from a single dmap.
+ */
+ if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
+ IREAD_UNLOCK(ipbmap);
+ return EINVAL;
+ }
+
+ if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
+ /* the free space is no longer available */
+ IREAD_UNLOCK(ipbmap);
+ return ENOSPC;
+ }
+
+ /* read in the dmap covering the extent */
+ lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
+ mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL) {
+ IREAD_UNLOCK(ipbmap);
+ return (EIO);
+ }
+ dp = (struct dmap *) mp->data;
+
+ /* try to allocate the requested extent */
+ rc = dbAllocNext(bmp, dp, blkno, nblocks);
+
+ IREAD_UNLOCK(ipbmap);
+
+ if (rc == 0) {
+ DBALLOC(bmp->db_DBmap, bmp->db_mapsize, blkno, nblocks);
+ mark_metapage_dirty(mp);
+ }
+ release_metapage(mp);
+
+ return (rc);
+}
+
+
+/*
+ * NAME: dbReAlloc()
+ *
+ * FUNCTION: attempt to extend a current allocation by a specified
+ * number of blocks.
+ *
+ * this routine attempts to satisfy the allocation request
+ * by first trying to extend the existing allocation in
+ * place by allocating the additional blocks as the blocks
+ * immediately following the current allocation. if these
+ * blocks are not available, this routine will attempt to
+ * allocate a new set of contiguous blocks large enough
+ * to cover the existing allocation plus the additional
+ * number of blocks required.
+ *
+ * PARAMETERS:
+ * ip - pointer to in-core inode requiring allocation.
+ * blkno - starting block of the current allocation.
+ * nblocks - number of contiguous blocks within the current
+ * allocation.
+ * addnblocks - number of blocks to add to the allocation.
+ * results - on successful return, set to the starting block number
+ * of the existing allocation if the existing allocation
+ * was extended in place or to a newly allocated contiguous
+ * range if the existing allocation could not be extended
+ * in place.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ */
+int
+dbReAlloc(struct inode *ip,
+ s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
+{
+ int rc;
+
+ /* try to extend the allocation in place.
+ */
+ if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
+ *results = blkno;
+ return (0);
+ } else {
+ if (rc != ENOSPC)
+ return (rc);
+ }
+
+ /* could not extend the allocation in place, so allocate a
+ * new set of blocks for the entire request (i.e. try to get
+ * a range of contiguous blocks large enough to cover the
+ * existing allocation plus the additional blocks.)
+ */
+ return (dbAlloc
+ (ip, blkno + nblocks - 1, addnblocks + nblocks, results));
+}
+
+
+/*
+ * NAME: dbExtend()
+ *
+ * FUNCTION: attempt to extend a current allocation by a specified
+ * number of blocks.
+ *
+ * this routine attempts to satisfy the allocation request
+ * by first trying to extend the existing allocation in
+ * place by allocating the additional blocks as the blocks
+ * immediately following the current allocation.
+ *
+ * PARAMETERS:
+ * ip - pointer to in-core inode requiring allocation.
+ * blkno - starting block of the current allocation.
+ * nblocks - number of contiguous blocks within the current
+ * allocation.
+ * addnblocks - number of blocks to add to the allocation.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ */
+int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
+{
+ struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
+ s64 lblkno, lastblkno, extblkno;
+ uint rel_block;
+ struct metapage *mp;
+ struct dmap *dp;
+ int rc;
+ struct inode *ipbmap = sbi->ipbmap;
+ struct bmap *bmp;
+
+ /*
+ * We don't want a non-aligned extent to cross a page boundary
+ */
+ if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
+ (rel_block + nblocks + addnblocks > sbi->nbperpage))
+ return (ENOSPC);
+
+ /* get the last block of the current allocation */
+ lastblkno = blkno + nblocks - 1;
+
+ /* determine the block number of the block following
+ * the existing allocation.
+ */
+ extblkno = lastblkno + 1;
+
+ IREAD_LOCK(ipbmap);
+
+ /* better be within the file system */
+ bmp = sbi->bmap;
+ assert(lastblkno >= 0 && lastblkno < bmp->db_mapsize);
+
+ /* we'll attempt to extend the current allocation in place by
+ * allocating the additional blocks as the blocks immediately
+ * following the current allocation. we only try to extend the
+ * current allocation in place if the number of additional blocks
+ * can fit into a dmap, the last block of the current allocation
+ * is not the last block of the file system, and the start of the
+ * inplace extension is not on an allocation group boundry.
+ */
+ if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
+ (extblkno & (bmp->db_agsize - 1)) == 0) {
+ IREAD_UNLOCK(ipbmap);
+ return (ENOSPC);
+ }
+
+ /* get the buffer for the dmap containing the first block
+ * of the extension.
+ */
+ lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
+ mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL) {
+ IREAD_UNLOCK(ipbmap);
+ return (EIO);
+ }
+
+ DBALLOCCK(bmp->db_DBmap, bmp->db_mapsize, blkno, nblocks);
+ dp = (struct dmap *) mp->data;
+
+ /* try to allocate the blocks immediately following the
+ * current allocation.
+ */
+ rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
+
+ IREAD_UNLOCK(ipbmap);
+
+ /* were we successful ? */
+ if (rc == 0) {
+ DBALLOC(bmp->db_DBmap, bmp->db_mapsize, extblkno,
+ addnblocks);
+ write_metapage(mp);
+ } else {
+ /* we were not successful */
+ release_metapage(mp);
+ assert(rc == ENOSPC || rc == EIO);
+ }
+
+ return (rc);
+}
+
+
+/*
+ * NAME: dbAllocNext()
+ *
+ * FUNCTION: attempt to allocate the blocks of the specified block
+ * range within a dmap.
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * dp - pointer to dmap.
+ * blkno - starting block number of the range.
+ * nblocks - number of contiguous free blocks of the range.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ *
+ * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
+ */
+static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks)
+{
+ int dbitno, word, rembits, nb, nwords, wbitno, nw;
+ int l2size;
+ s8 *leaf;
+ u32 mask;
+
+ /* pick up a pointer to the leaves of the dmap tree.
+ */
+ leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
+
+ /* determine the bit number and word within the dmap of the
+ * starting block.
+ */
+ dbitno = blkno & (BPERDMAP - 1);
+ word = dbitno >> L2DBWORD;
+
+ /* check if the specified block range is contained within
+ * this dmap.
+ */
+ if (dbitno + nblocks > BPERDMAP)
+ return (ENOSPC);
+
+ /* check if the starting leaf indicates that anything
+ * is free.
+ */
+ if (leaf[word] == NOFREE)
+ return (ENOSPC);
+
+ /* check the dmaps words corresponding to block range to see
+ * if the block range is free. not all bits of the first and
+ * last words may be contained within the block range. if this
+ * is the case, we'll work against those words (i.e. partial first
+ * and/or last) on an individual basis (a single pass) and examine
+ * the actual bits to determine if they are free. a single pass
+ * will be used for all dmap words fully contained within the
+ * specified range. within this pass, the leaves of the dmap
+ * tree will be examined to determine if the blocks are free. a
+ * single leaf may describe the free space of multiple dmap
+ * words, so we may visit only a subset of the actual leaves
+ * corresponding to the dmap words of the block range.
+ */
+ for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
+ /* determine the bit number within the word and
+ * the number of bits within the word.
+ */
+ wbitno = dbitno & (DBWORD - 1);
+ nb = min(rembits, DBWORD - wbitno);
+
+ /* check if only part of the word is to be examined.
+ */
+ if (nb < DBWORD) {
+ /* check if the bits are free.
+ */
+ mask = (ONES << (DBWORD - nb) >> wbitno);
+ if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
+ return (ENOSPC);
+
+ word += 1;
+ } else {
+ /* one or more dmap words are fully contained
+ * within the block range. determine how many
+ * words and how many bits.
+ */
+ nwords = rembits >> L2DBWORD;
+ nb = nwords << L2DBWORD;
+
+ /* now examine the appropriate leaves to determine
+ * if the blocks are free.
+ */
+ while (nwords > 0) {
+ /* does the leaf describe any free space ?
+ */
+ if (leaf[word] < BUDMIN)
+ return (ENOSPC);
+
+ /* determine the l2 number of bits provided
+ * by this leaf.
+ */
+ l2size =
+ min((int)leaf[word], NLSTOL2BSZ(nwords));
+
+ /* determine how many words were handled.
+ */
+ nw = BUDSIZE(l2size, BUDMIN);
+
+ nwords -= nw;
+ word += nw;
+ }
+ }
+ }
+
+ /* allocate the blocks.
+ */
+ return (dbAllocDmap(bmp, dp, blkno, nblocks));
+}
+
+
+/*
+ * NAME: dbAllocNear()
+ *
+ * FUNCTION: attempt to allocate a number of contiguous free blocks near
+ * a specified block (hint) within a dmap.
+ *
+ * starting with the dmap leaf that covers the hint, we'll
+ * check the next four contiguous leaves for sufficient free
+ * space. if sufficient free space is found, we'll allocate
+ * the desired free space.
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * dp - pointer to dmap.
+ * blkno - block number to allocate near.
+ * nblocks - actual number of contiguous free blocks desired.
+ * l2nb - log2 number of contiguous free blocks desired.
+ * results - on successful return, set to the starting block number
+ * of the newly allocated range.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ *
+ * serialization: IREAD_LOCK(ipbmap) held on entry/exit;
+ */
+static int
+dbAllocNear(struct bmap * bmp,
+ struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
+{
+ int word, lword, rc;
+ s8 *leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
+
+ /* determine the word within the dmap that holds the hint
+ * (i.e. blkno). also, determine the last word in the dmap
+ * that we'll include in our examination.
+ */
+ word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
+ lword = min(word + 4, LPERDMAP);
+
+ /* examine the leaves for sufficient free space.
+ */
+ for (; word < lword; word++) {
+ /* does the leaf describe sufficient free space ?
+ */
+ if (leaf[word] < l2nb)
+ continue;
+
+ /* determine the block number within the file system
+ * of the first block described by this dmap word.
+ */
+ blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
+
+ /* if not all bits of the dmap word are free, get the
+ * starting bit number within the dmap word of the required
+ * string of free bits and adjust the block number with the
+ * value.
+ */
+ if (leaf[word] < BUDMIN)
+ blkno +=
+ dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
+
+ /* allocate the blocks.
+ */
+ if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
+ *results = blkno;
+
+ return (rc);
+ }
+
+ return (ENOSPC);
+}
+
+
+/*
+ * NAME: dbAllocAG()
+ *
+ * FUNCTION: attempt to allocate the specified number of contiguous
+ * free blocks within the specified allocation group.
+ *
+ * unless the allocation group size is equal to the number
+ * of blocks per dmap, the dmap control pages will be used to
+ * find the required free space, if available. we start the
+ * search at the highest dmap control page level which
+ * distinctly describes the allocation group's free space
+ * (i.e. the highest level at which the allocation group's
+ * free space is not mixed in with that of any other group).
+ * in addition, we start the search within this level at a
+ * height of the dmapctl dmtree at which the nodes distinctly
+ * describe the allocation group's free space. at this height,
+ * the allocation group's free space may be represented by 1
+ * or two sub-trees, depending on the allocation group size.
+ * we search the top nodes of these subtrees left to right for
+ * sufficient free space. if sufficient free space is found,
+ * the subtree is searched to find the leftmost leaf that
+ * has free space. once we have made it to the leaf, we
+ * move the search to the next lower level dmap control page
+ * corresponding to this leaf. we continue down the dmap control
+ * pages until we find the dmap that contains or starts the
+ * sufficient free space and we allocate at this dmap.
+ *
+ * if the allocation group size is equal to the dmap size,
+ * we'll start at the dmap corresponding to the allocation
+ * group and attempt the allocation at this level.
+ *
+ * the dmap control page search is also not performed if the
+ * allocation group is completely free and we go to the first
+ * dmap of the allocation group to do the allocation. this is
+ * done because the allocation group may be part (not the first
+ * part) of a larger binary buddy system, causing the dmap
+ * control pages to indicate no free space (NOFREE) within
+ * the allocation group.
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * agno - allocation group number.
+ * nblocks - actual number of contiguous free blocks desired.
+ * l2nb - log2 number of contiguous free blocks desired.
+ * results - on successful return, set to the starting block number
+ * of the newly allocated range.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ *
+ * note: IWRITE_LOCK(ipmap) held on entry/exit;
+ */
+static int
+dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
+{
+ struct metapage *mp;
+ struct dmapctl *dcp;
+ int rc, ti, i, k, m, n, agperlev;
+ s64 blkno, lblkno;
+ int budmin;
+
+ /* allocation request should not be for more than the
+ * allocation group size.
+ */
+ assert(l2nb <= bmp->db_agl2size);
+
+ /* determine the starting block number of the allocation
+ * group.
+ */
+ blkno = (s64) agno << bmp->db_agl2size;
+
+ /* check if the allocation group size is the minimum allocation
+ * group size or if the allocation group is completely free. if
+ * the allocation group size is the minimum size of BPERDMAP (i.e.
+ * 1 dmap), there is no need to search the dmap control page (below)
+ * that fully describes the allocation group since the allocation
+ * group is already fully described by a dmap. in this case, we
+ * just call dbAllocCtl() to search the dmap tree and allocate the
+ * required space if available.
+ *
+ * if the allocation group is completely free, dbAllocCtl() is
+ * also called to allocate the required space. this is done for
+ * two reasons. first, it makes no sense searching the dmap control
+ * pages for free space when we know that free space exists. second,
+ * the dmap control pages may indicate that the allocation group
+ * has no free space if the allocation group is part (not the first
+ * part) of a larger binary buddy system.
+ */
+ if (bmp->db_agsize == BPERDMAP
+ || bmp->db_agfree[agno] == bmp->db_agsize) {
+ rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
+ /* assert(!(rc == ENOSPC && bmp->db_agfree[agno] == bmp->db_agsize)); */
+ if ((rc == ENOSPC) &&
+ (bmp->db_agfree[agno] == bmp->db_agsize)) {
+ jERROR(1,
+ ("dbAllocAG: removed assert, but still need to debug here\nblkno = 0x%Lx, nblocks = 0x%Lx\n",
+ (unsigned long long) blkno,
+ (unsigned long long) nblocks));
+ }
+ return (rc);
+ }
+
+ /* the buffer for the dmap control page that fully describes the
+ * allocation group.
+ */
+ lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
+ mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL)
+ return (EIO);
+ dcp = (struct dmapctl *) mp->data;
+ budmin = dcp->budmin;
+
+ /* search the subtree(s) of the dmap control page that describes
+ * the allocation group, looking for sufficient free space. to begin,
+ * determine how many allocation groups are represented in a dmap
+ * control page at the control page level (i.e. L0, L1, L2) that
+ * fully describes an allocation group. next, determine the starting
+ * tree index of this allocation group within the control page.
+ */
+ agperlev =
+ (1 << (L2LPERCTL - (bmp->db_agheigth << 1))) / bmp->db_agwidth;
+ ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
+
+ /* dmap control page trees fan-out by 4 and a single allocation
+ * group may be described by 1 or 2 subtrees within the ag level
+ * dmap control page, depending upon the ag size. examine the ag's
+ * subtrees for sufficient free space, starting with the leftmost
+ * subtree.
+ */
+ for (i = 0; i < bmp->db_agwidth; i++, ti++) {
+ /* is there sufficient free space ?
+ */
+ if (l2nb > dcp->stree[ti])
+ continue;
+
+ /* sufficient free space found in a subtree. now search down
+ * the subtree to find the leftmost leaf that describes this
+ * free space.
+ */
+ for (k = bmp->db_agheigth; k > 0; k--) {
+ for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
+ if (l2nb <= dcp->stree[m + n]) {
+ ti = m + n;
+ break;
+ }
+ }
+ assert(n < 4);
+ }
+
+ /* determine the block number within the file system
+ * that corresponds to this leaf.
+ */
+ if (bmp->db_aglevel == 2)
+ blkno = 0;
+ else if (bmp->db_aglevel == 1)
+ blkno &= ~(MAXL1SIZE - 1);
+ else /* bmp->db_aglevel == 0 */
+ blkno &= ~(MAXL0SIZE - 1);
+
+ blkno +=
+ ((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
+
+ /* release the buffer in preparation for going down
+ * the next level of dmap control pages.
+ */
+ release_metapage(mp);
+
+ /* check if we need to continue to search down the lower
+ * level dmap control pages. we need to if the number of
+ * blocks required is less than maximum number of blocks
+ * described at the next lower level.
+ */
+ if (l2nb < budmin) {
+
+ /* search the lower level dmap control pages to get
+ * the starting block number of the the dmap that
+ * contains or starts off the free space.
+ */
+ if ((rc =
+ dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
+ &blkno))) {
+ assert(rc != ENOSPC);
+ return (rc);
+ }
+ }
+
+ /* allocate the blocks.
+ */
+ rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
+ assert(rc != ENOSPC);
+ return (rc);
+ }
+
+ /* no space in the allocation group. release the buffer and
+ * return ENOSPC.
+ */
+ release_metapage(mp);
+
+ return (ENOSPC);
+}
+
+
+/*
+ * NAME: dbAllocAny()
+ *
+ * FUNCTION: attempt to allocate the specified number of contiguous
+ * free blocks anywhere in the file system.
+ *
+ * dbAllocAny() attempts to find the sufficient free space by
+ * searching down the dmap control pages, starting with the
+ * highest level (i.e. L0, L1, L2) control page. if free space
+ * large enough to satisfy the desired free space is found, the
+ * desired free space is allocated.
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * nblocks - actual number of contiguous free blocks desired.
+ * l2nb - log2 number of contiguous free blocks desired.
+ * results - on successful return, set to the starting block number
+ * of the newly allocated range.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ *
+ * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
+{
+ int rc;
+ s64 blkno = 0;
+
+ /* starting with the top level dmap control page, search
+ * down the dmap control levels for sufficient free space.
+ * if free space is found, dbFindCtl() returns the starting
+ * block number of the dmap that contains or starts off the
+ * range of free space.
+ */
+ if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
+ return (rc);
+
+ /* allocate the blocks.
+ */
+ rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
+ assert(rc != ENOSPC);
+ return (rc);
+}
+
+
+/*
+ * NAME: dbFindCtl()
+ *
+ * FUNCTION: starting at a specified dmap control page level and block
+ * number, search down the dmap control levels for a range of
+ * contiguous free blocks large enough to satisfy an allocation
+ * request for the specified number of free blocks.
+ *
+ * if sufficient contiguous free blocks are found, this routine
+ * returns the starting block number within a dmap page that
+ * contains or starts a range of contiqious free blocks that
+ * is sufficient in size.
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * level - starting dmap control page level.
+ * l2nb - log2 number of contiguous free blocks desired.
+ * *blkno - on entry, starting block number for conducting the search.
+ * on successful return, the first block within a dmap page
+ * that contains or starts a range of contiguous free blocks.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ *
+ * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
+{
+ int rc, leafidx, lev;
+ s64 b, lblkno;
+ struct dmapctl *dcp;
+ int budmin;
+ struct metapage *mp;
+
+ /* starting at the specified dmap control page level and block
+ * number, search down the dmap control levels for the starting
+ * block number of a dmap page that contains or starts off
+ * sufficient free blocks.
+ */
+ for (lev = level, b = *blkno; lev >= 0; lev--) {
+ /* get the buffer of the dmap control page for the block
+ * number and level (i.e. L0, L1, L2).
+ */
+ lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
+ mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL)
+ return (EIO);
+ dcp = (struct dmapctl *) mp->data;
+ budmin = dcp->budmin;
+
+ /* search the tree within the dmap control page for
+ * sufficent free space. if sufficient free space is found,
+ * dbFindLeaf() returns the index of the leaf at which
+ * free space was found.
+ */
+ rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
+
+ /* release the buffer.
+ */
+ release_metapage(mp);
+
+ /* space found ?
+ */
+ if (rc) {
+ assert(lev == level);
+ return (ENOSPC);
+ }
+
+ /* adjust the block number to reflect the location within
+ * the dmap control page (i.e. the leaf) at which free
+ * space was found.
+ */
+ b += (((s64) leafidx) << budmin);
+
+ /* we stop the search at this dmap control page level if
+ * the number of blocks required is greater than or equal
+ * to the maximum number of blocks described at the next
+ * (lower) level.
+ */
+ if (l2nb >= budmin)
+ break;
+ }
+
+ *blkno = b;
+ return (0);
+}
+
+
+/*
+ * NAME: dbAllocCtl()
+ *
+ * FUNCTION: attempt to allocate a specified number of contiguous
+ * blocks starting within a specific dmap.
+ *
+ * this routine is called by higher level routines that search
+ * the dmap control pages above the actual dmaps for contiguous
+ * free space. the result of successful searches by these
+ * routines are the starting block numbers within dmaps, with
+ * the dmaps themselves containing the desired contiguous free
+ * space or starting a contiguous free space of desired size
+ * that is made up of the blocks of one or more dmaps. these
+ * calls should not fail due to insufficent resources.
+ *
+ * this routine is called in some cases where it is not known
+ * whether it will fail due to insufficient resources. more
+ * specifically, this occurs when allocating from an allocation
+ * group whose size is equal to the number of blocks per dmap.
+ * in this case, the dmap control pages are not examined prior
+ * to calling this routine (to save pathlength) and the call
+ * might fail.
+ *
+ * for a request size that fits within a dmap, this routine relies
+ * upon the dmap's dmtree to find the requested contiguous free
+ * space. for request sizes that are larger than a dmap, the
+ * requested free space will start at the first block of the
+ * first dmap (i.e. blkno).
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * nblocks - actual number of contiguous free blocks to allocate.
+ * l2nb - log2 number of contiguous free blocks to allocate.
+ * blkno - starting block number of the dmap to start the allocation
+ * from.
+ * results - on successful return, set to the starting block number
+ * of the newly allocated range.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ *
+ * serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static int
+dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
+{
+ int rc, nb;
+ s64 b, lblkno, n;
+ struct metapage *mp;
+ struct dmap *dp;
+
+ /* check if the allocation request is confined to a single dmap.
+ */
+ if (l2nb <= L2BPERDMAP) {
+ /* get the buffer for the dmap.
+ */
+ lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
+ mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL)
+ return (EIO);
+ dp = (struct dmap *) mp->data;
+
+ /* try to allocate the blocks.
+ */
+ rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
+ if (rc == 0)
+ mark_metapage_dirty(mp);
+
+ release_metapage(mp);
+
+ return (rc);
+ }
+
+ /* allocation request involving multiple dmaps. it must start on
+ * a dmap boundary.
+ */
+ assert((blkno & (BPERDMAP - 1)) == 0);
+
+ /* allocate the blocks dmap by dmap.
+ */
+ for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
+ /* get the buffer for the dmap.
+ */
+ lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
+ mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL) {
+ rc = EIO;
+ goto backout;
+ }
+ dp = (struct dmap *) mp->data;
+
+ /* the dmap better be all free.
+ */
+ assert(dp->tree.stree[ROOT] == L2BPERDMAP);
+
+ /* determine how many blocks to allocate from this dmap.
+ */
+ nb = min(n, (s64)BPERDMAP);
+
+ /* allocate the blocks from the dmap.
+ */
+ if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
+ release_metapage(mp);
+ goto backout;
+ }
+
+ /* write the buffer.
+ */
+ write_metapage(mp);
+ }
+
+ /* set the results (starting block number) and return.
+ */
+ *results = blkno;
+ return (0);
+
+ /* something failed in handling an allocation request involving
+ * multiple dmaps. we'll try to clean up by backing out any
+ * allocation that has already happened for this request. if
+ * we fail in backing out the allocation, we'll mark the file
+ * system to indicate that blocks have been leaked.
+ */
+ backout:
+
+ /* try to backout the allocations dmap by dmap.
+ */
+ for (n = nblocks - n, b = blkno; n > 0;
+ n -= BPERDMAP, b += BPERDMAP) {
+ /* get the buffer for this dmap.
+ */
+ lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
+ mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL) {
+ /* could not back out. mark the file system
+ * to indicate that we have leaked blocks.
+ */
+ fsDirty(); /* !!! */
+ jERROR(1,
+ ("dbAllocCtl: I/O Error: Block Leakage.\n"));
+ continue;
+ }
+ dp = (struct dmap *) mp->data;
+
+ /* free the blocks is this dmap.
+ */
+ if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
+ /* could not back out. mark the file system
+ * to indicate that we have leaked blocks.
+ */
+ release_metapage(mp);
+ fsDirty(); /* !!! */
+ jERROR(1, ("dbAllocCtl: Block Leakage.\n"));
+ continue;
+ }
+
+ /* write the buffer.
+ */
+ write_metapage(mp);
+ }
+
+ return (rc);
+}
+
+
+/*
+ * NAME: dbAllocDmapLev()
+ *
+ * FUNCTION: attempt to allocate a specified number of contiguous blocks
+ * from a specified dmap.
+ *
+ * this routine checks if the contiguous blocks are available.
+ * if so, nblocks of blocks are allocated; otherwise, ENOSPC is
+ * returned.
+ *
+ * PARAMETERS:
+ * mp - pointer to bmap descriptor
+ * dp - pointer to dmap to attempt to allocate blocks from.
+ * l2nb - log2 number of contiguous block desired.
+ * nblocks - actual number of contiguous block desired.
+ * results - on successful return, set to the starting block number
+ * of the newly allocated range.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient disk resources
+ * EIO - i/o error
+ *
+ * serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
+ * IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
+ */
+static int
+dbAllocDmapLev(struct bmap * bmp,
+ struct dmap * dp, int nblocks, int l2nb, s64 * results)
+{
+ s64 blkno;
+ int leafidx, rc;
+
+ /* can't be more than a dmaps worth of blocks */
+ assert(l2nb <= L2BPERDMAP);
+
+ /* search the tree within the dmap page for sufficient
+ * free space. if sufficient free space is found, dbFindLeaf()
+ * returns the index of the leaf at which free space was found.
+ */
+ if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
+ return (ENOSPC);
+
+ /* determine the block number within the file system corresponding
+ * to the leaf at which free space was found.
+ */
+ blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
+
+ /* if not all bits of the dmap word are free, get the starting
+ * bit number within the dmap word of the required string of free
+ * bits and adjust the block number with this value.
+ */
+ if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
+ blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
+
+ /* allocate the blocks */
+ if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
+ *results = blkno;
+
+ return (rc);
+}
+
+
+/*
+ * NAME: dbAllocDmap()
+ *
+ * FUNCTION: adjust the disk allocation map to reflect the allocation
+ * of a specified block range within a dmap.
+ *
+ * this routine allocates the specified blocks from the dmap
+ * through a call to dbAllocBits(). if the allocation of the
+ * block range causes the maximum string of free blocks within
+ * the dmap to change (i.e. the value of the root of the dmap's
+ * dmtree), this routine will cause this change to be reflected
+ * up through the appropriate levels of the dmap control pages
+ * by a call to dbAdjCtl() for the L0 dmap control page that
+ * covers this dmap.
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * dp - pointer to dmap to allocate the block range from.
+ * blkno - starting block number of the block to be allocated.
+ * nblocks - number of blocks to be allocated.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * EIO - i/o error
+ *
+ * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks)
+{
+ s8 oldroot;
+ int rc;
+
+ /* save the current value of the root (i.e. maximum free string)
+ * of the dmap tree.
+ */
+ oldroot = dp->tree.stree[ROOT];
+
+ /* allocate the specified (blocks) bits */
+ dbAllocBits(bmp, dp, blkno, nblocks);
+
+ /* if the root has not changed, done. */
+ if (dp->tree.stree[ROOT] == oldroot)
+ return (0);
+
+ /* root changed. bubble the change up to the dmap control pages.
+ * if the adjustment of the upper level control pages fails,
+ * backout the bit allocation (thus making everything consistent).
+ */
+ if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
+ dbFreeBits(bmp, dp, blkno, nblocks);
+
+ return (rc);
+}
+
+
+/*
+ * NAME: dbFreeDmap()
+ *
+ * FUNCTION: adjust the disk allocation map to reflect the allocation
+ * of a specified block range within a dmap.
+ *
+ * this routine frees the specified blocks from the dmap through
+ * a call to dbFreeBits(). if the deallocation of the block range
+ * causes the maximum string of free blocks within the dmap to
+ * change (i.e. the value of the root of the dmap's dmtree), this
+ * routine will cause this change to be reflected up through the
+ * appropriate levels of the dmap control pages by a call to
+ * dbAdjCtl() for the L0 dmap control page that covers this dmap.
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * dp - pointer to dmap to free the block range from.
+ * blkno - starting block number of the block to be freed.
+ * nblocks - number of blocks to be freed.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * EIO - i/o error
+ *
+ * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks)
+{
+ s8 oldroot;
+ int rc, word;
+
+ /* save the current value of the root (i.e. maximum free string)
+ * of the dmap tree.
+ */
+ oldroot = dp->tree.stree[ROOT];
+
+ /* free the specified (blocks) bits */
+ dbFreeBits(bmp, dp, blkno, nblocks);
+
+ /* if the root has not changed, done. */
+ if (dp->tree.stree[ROOT] == oldroot)
+ return (0);
+
+ /* root changed. bubble the change up to the dmap control pages.
+ * if the adjustment of the upper level control pages fails,
+ * backout the deallocation.
+ */
+ if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
+ word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
+
+ /* as part of backing out the deallocation, we will have
+ * to back split the dmap tree if the deallocation caused
+ * the freed blocks to become part of a larger binary buddy
+ * system.
+ */
+ if (dp->tree.stree[word] == NOFREE)
+ dbBackSplit((dmtree_t *) & dp->tree, word);
+
+ dbAllocBits(bmp, dp, blkno, nblocks);
+ }
+
+ return (rc);
+}
+
+
+/*
+ * NAME: dbAllocBits()
+ *
+ * FUNCTION: allocate a specified block range from a dmap.
+ *
+ * this routine updates the dmap to reflect the working
+ * state allocation of the specified block range. it directly
+ * updates the bits of the working map and causes the adjustment
+ * of the binary buddy system described by the dmap's dmtree
+ * leaves to reflect the bits allocated. it also causes the
+ * dmap's dmtree, as a whole, to reflect the allocated range.
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * dp - pointer to dmap to allocate bits from.
+ * blkno - starting block number of the bits to be allocated.
+ * nblocks - number of bits to be allocated.
+ *
+ * RETURN VALUES: none
+ *
+ * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks)
+{
+ int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
+ dmtree_t *tp = (dmtree_t *) & dp->tree;
+ int size;
+ s8 *leaf;
+
+ /* pick up a pointer to the leaves of the dmap tree */
+ leaf = dp->tree.stree + LEAFIND;
+
+ /* determine the bit number and word within the dmap of the
+ * starting block.
+ */
+ dbitno = blkno & (BPERDMAP - 1);
+ word = dbitno >> L2DBWORD;
+
+ /* block range better be within the dmap */
+ assert(dbitno + nblocks <= BPERDMAP);
+
+ /* allocate the bits of the dmap's words corresponding to the block
+ * range. not all bits of the first and last words may be contained
+ * within the block range. if this is the case, we'll work against
+ * those words (i.e. partial first and/or last) on an individual basis
+ * (a single pass), allocating the bits of interest by hand and
+ * updating the leaf corresponding to the dmap word. a single pass
+ * will be used for all dmap words fully contained within the
+ * specified range. within this pass, the bits of all fully contained
+ * dmap words will be marked as free in a single shot and the leaves
+ * will be updated. a single leaf may describe the free space of
+ * multiple dmap words, so we may update only a subset of the actual
+ * leaves corresponding to the dmap words of the block range.
+ */
+ for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
+ /* determine the bit number within the word and
+ * the number of bits within the word.
+ */
+ wbitno = dbitno & (DBWORD - 1);
+ nb = min(rembits, DBWORD - wbitno);
+
+ /* check if only part of a word is to be allocated.
+ */
+ if (nb < DBWORD) {
+ /* allocate (set to 1) the appropriate bits within
+ * this dmap word.
+ */
+ dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
+ >> wbitno);
+
+ /* update the leaf for this dmap word. in addition
+ * to setting the leaf value to the binary buddy max
+ * of the updated dmap word, dbSplit() will split
+ * the binary system of the leaves if need be.
+ */
+ dbSplit(tp, word, BUDMIN,
+ dbMaxBud((u8 *) & dp->wmap[word]));
+
+ word += 1;
+ } else {
+ /* one or more dmap words are fully contained
+ * within the block range. determine how many
+ * words and allocate (set to 1) the bits of these
+ * words.
+ */
+ nwords = rembits >> L2DBWORD;
+ memset(&dp->wmap[word], (int) ONES, nwords * 4);
+
+ /* determine how many bits.
+ */
+ nb = nwords << L2DBWORD;
+
+ /* now update the appropriate leaves to reflect
+ * the allocated words.
+ */
+ for (; nwords > 0; nwords -= nw) {
+ assert(leaf[word] >= BUDMIN);
+
+ /* determine what the leaf value should be
+ * updated to as the minimum of the l2 number
+ * of bits being allocated and the l2 number
+ * of bits currently described by this leaf.
+ */
+ size = min((int)leaf[word], NLSTOL2BSZ(nwords));
+
+ /* update the leaf to reflect the allocation.
+ * in addition to setting the leaf value to
+ * NOFREE, dbSplit() will split the binary
+ * system of the leaves to reflect the current
+ * allocation (size).
+ */
+ dbSplit(tp, word, size, NOFREE);
+
+ /* get the number of dmap words handled */
+ nw = BUDSIZE(size, BUDMIN);
+ word += nw;
+ }
+ }
+ }
+
+ /* update the free count for this dmap */
+ dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) - nblocks);
+
+ BMAP_LOCK(bmp);
+
+ /* if this allocation group is completely free,
+ * update the maximum allocation group number if this allocation
+ * group is the new max.
+ */
+ agno = blkno >> bmp->db_agl2size;
+ if (agno > bmp->db_maxag)
+ bmp->db_maxag = agno;
+
+ /* update the free count for the allocation group and map */
+ bmp->db_agfree[agno] -= nblocks;
+ bmp->db_nfree -= nblocks;
+
+ BMAP_UNLOCK(bmp);
+}
+
+
+/*
+ * NAME: dbFreeBits()
+ *
+ * FUNCTION: free a specified block range from a dmap.
+ *
+ * this routine updates the dmap to reflect the working
+ * state allocation of the specified block range. it directly
+ * updates the bits of the working map and causes the adjustment
+ * of the binary buddy system described by the dmap's dmtree
+ * leaves to reflect the bits freed. it also causes the dmap's
+ * dmtree, as a whole, to reflect the deallocated range.
+ *
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * dp - pointer to dmap to free bits from.
+ * blkno - starting block number of the bits to be freed.
+ * nblocks - number of bits to be freed.
+ *
+ * RETURN VALUES: none
+ *
+ * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static void dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks)
+{
+ int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
+ dmtree_t *tp = (dmtree_t *) & dp->tree;
+ int size;
+
+ /* determine the bit number and word within the dmap of the
+ * starting block.
+ */
+ dbitno = blkno & (BPERDMAP - 1);
+ word = dbitno >> L2DBWORD;
+
+ /* block range better be within the dmap.
+ */
+ assert(dbitno + nblocks <= BPERDMAP);
+
+ /* free the bits of the dmaps words corresponding to the block range.
+ * not all bits of the first and last words may be contained within
+ * the block range. if this is the case, we'll work against those
+ * words (i.e. partial first and/or last) on an individual basis
+ * (a single pass), freeing the bits of interest by hand and updating
+ * the leaf corresponding to the dmap word. a single pass will be used
+ * for all dmap words fully contained within the specified range.
+ * within this pass, the bits of all fully contained dmap words will
+ * be marked as free in a single shot and the leaves will be updated. a
+ * single leaf may describe the free space of multiple dmap words,
+ * so we may update only a subset of the actual leaves corresponding
+ * to the dmap words of the block range.
+ *
+ * dbJoin() is used to update leaf values and will join the binary
+ * buddy system of the leaves if the new leaf values indicate this
+ * should be done.
+ */
+ for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
+ /* determine the bit number within the word and
+ * the number of bits within the word.
+ */
+ wbitno = dbitno & (DBWORD - 1);
+ nb = min(rembits, DBWORD - wbitno);
+
+ /* check if only part of a word is to be freed.
+ */
+ if (nb < DBWORD) {
+ /* free (zero) the appropriate bits within this
+ * dmap word.
+ */
+ dp->wmap[word] &=
+ cpu_to_le32(~(ONES << (DBWORD - nb)
+ >> wbitno));
+
+ /* update the leaf for this dmap word.
+ */
+ dbJoin(tp, word,
+ dbMaxBud((u8 *) & dp->wmap[word]));
+
+ word += 1;
+ } else {
+ /* one or more dmap words are fully contained
+ * within the block range. determine how many
+ * words and free (zero) the bits of these words.
+ */
+ nwords = rembits >> L2DBWORD;
+ memset(&dp->wmap[word], 0, nwords * 4);
+
+ /* determine how many bits.
+ */
+ nb = nwords << L2DBWORD;
+
+ /* now update the appropriate leaves to reflect
+ * the freed words.
+ */
+ for (; nwords > 0; nwords -= nw) {
+ /* determine what the leaf value should be
+ * updated to as the minimum of the l2 number
+ * of bits being freed and the l2 (max) number
+ * of bits that can be described by this leaf.
+ */
+ size =
+ min(LITOL2BSZ
+ (word, L2LPERDMAP, BUDMIN),
+ NLSTOL2BSZ(nwords));
+
+ /* update the leaf.
+ */
+ dbJoin(tp, word, size);
+
+ /* get the number of dmap words handled.
+ */
+ nw = BUDSIZE(size, BUDMIN);
+ word += nw;
+ }
+ }
+ }
+
+ /* update the free count for this dmap.
+ */
+ dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) + nblocks);
+
+ BMAP_LOCK(bmp);
+
+ /* update the free count for the allocation group and
+ * map.
+ */
+ agno = blkno >> bmp->db_agl2size;
+ bmp->db_nfree += nblocks;
+ bmp->db_agfree[agno] += nblocks;
+
+ /* check if this allocation group is not completely free and
+ * if it is currently the maximum (rightmost) allocation group.
+ * if so, establish the new maximum allocation group number by
+ * searching left for the first allocation group with allocation.
+ */
+ if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
+ (agno == bmp->db_numag - 1 &&
+ bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
+ while (bmp->db_maxag > 0) {
+ bmp->db_maxag -= 1;
+ if (bmp->db_agfree[bmp->db_maxag] !=
+ bmp->db_agsize)
+ break;
+ }
+
+ /* re-establish the allocation group preference if the
+ * current preference is right of the maximum allocation
+ * group.
+ */
+ if (bmp->db_agpref > bmp->db_maxag)
+ bmp->db_agpref = bmp->db_maxag;
+ }
+
+ BMAP_UNLOCK(bmp);
+}
+
+
+/*
+ * NAME: dbAdjCtl()
+ *
+ * FUNCTION: adjust a dmap control page at a specified level to reflect
+ * the change in a lower level dmap or dmap control page's
+ * maximum string of free blocks (i.e. a change in the root
+ * of the lower level object's dmtree) due to the allocation
+ * or deallocation of a range of blocks with a single dmap.
+ *
+ * on entry, this routine is provided with the new value of
+ * the lower level dmap or dmap control page root and the
+ * starting block number of the block range whose allocation
+ * or deallocation resulted in the root change. this range
+ * is respresented by a single leaf of the current dmapctl
+ * and the leaf will be updated with this value, possibly
+ * causing a binary buddy system within the leaves to be
+ * split or joined. the update may also cause the dmapctl's
+ * dmtree to be updated.
+ *
+ * if the adjustment of the dmap control page, itself, causes its
+ * root to change, this change will be bubbled up to the next dmap
+ * control level by a recursive call to this routine, specifying
+ * the new root value and the next dmap control page level to
+ * be adjusted.
+ * PARAMETERS:
+ * bmp - pointer to bmap descriptor
+ * blkno - the first block of a block range within a dmap. it is
+ * the allocation or deallocation of this block range that
+ * requires the dmap control page to be adjusted.
+ * newval - the new value of the lower level dmap or dmap control
+ * page root.
+ * alloc - TRUE if adjustment is due to an allocation.
+ * level - current level of dmap control page (i.e. L0, L1, L2) to
+ * be adjusted.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * EIO - i/o error
+ *
+ * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static int
+dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
+{
+ struct metapage *mp;
+ s8 oldroot;
+ int oldval;
+ s64 lblkno;
+ struct dmapctl *dcp;
+ int rc, leafno, ti;
+
+ /* get the buffer for the dmap control page for the specified
+ * block number and control page level.
+ */
+ lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
+ mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL)
+ return (EIO);
+ dcp = (struct dmapctl *) mp->data;
+
+ /* determine the leaf number corresponding to the block and
+ * the index within the dmap control tree.
+ */
+ leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
+ ti = leafno + le32_to_cpu(dcp->leafidx);
+
+ /* save the current leaf value and the current root level (i.e.
+ * maximum l2 free string described by this dmapctl).
+ */
+ oldval = dcp->stree[ti];
+ oldroot = dcp->stree[ROOT];
+
+ /* check if this is a control page update for an allocation.
+ * if so, update the leaf to reflect the new leaf value using
+ * dbSplit(); otherwise (deallocation), use dbJoin() to udpate
+ * the leaf with the new value. in addition to updating the
+ * leaf, dbSplit() will also split the binary buddy system of
+ * the leaves, if required, and bubble new values within the
+ * dmapctl tree, if required. similarly, dbJoin() will join
+ * the binary buddy system of leaves and bubble new values up
+ * the dmapctl tree as required by the new leaf value.
+ */
+ if (alloc) {
+ /* check if we are in the middle of a binary buddy
+ * system. this happens when we are performing the
+ * first allocation out of an allocation group that
+ * is part (not the first part) of a larger binary
+ * buddy system. if we are in the middle, back split
+ * the system prior to calling dbSplit() which assumes
+ * that it is at the front of a binary buddy system.
+ */
+ if (oldval == NOFREE) {
+ dbBackSplit((dmtree_t *) dcp, leafno);
+ oldval = dcp->stree[ti];
+ }
+ dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
+ } else {
+ dbJoin((dmtree_t *) dcp, leafno, newval);
+ }
+
+ /* check if the root of the current dmap control page changed due
+ * to the update and if the current dmap control page is not at
+ * the current top level (i.e. L0, L1, L2) of the map. if so (i.e.
+ * root changed and this is not the top level), call this routine
+ * again (recursion) for the next higher level of the mapping to
+ * reflect the change in root for the current dmap control page.
+ */
+ if (dcp->stree[ROOT] != oldroot) {
+ /* are we below the top level of the map. if so,
+ * bubble the root up to the next higher level.
+ */
+ if (level < bmp->db_maxlevel) {
+ /* bubble up the new root of this dmap control page to
+ * the next level.
+ */
+ if ((rc =
+ dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
+ level + 1))) {
+ /* something went wrong in bubbling up the new
+ * root value, so backout the changes to the
+ * current dmap control page.
+ */
+ if (alloc) {
+ dbJoin((dmtree_t *) dcp, leafno,
+ oldval);
+ } else {
+ /* the dbJoin() above might have
+ * caused a larger binary buddy system
+ * to form and we may now be in the
+ * middle of it. if this is the case,
+ * back split the buddies.
+ */
+ if (dcp->stree[ti] == NOFREE)
+ dbBackSplit((dmtree_t *)
+ dcp, leafno);
+ dbSplit((dmtree_t *) dcp, leafno,
+ dcp->budmin, oldval);
+ }
+
+ /* release the buffer and return the error.
+ */
+ release_metapage(mp);
+ return (rc);
+ }
+ } else {
+ /* we're at the top level of the map. update
+ * the bmap control page to reflect the size
+ * of the maximum free buddy system.
+ */
+ assert(level == bmp->db_maxlevel);
+ assert(bmp->db_maxfreebud == oldroot);
+ bmp->db_maxfreebud = dcp->stree[ROOT];
+ }
+ }
+
+ /* write the buffer.
+ */
+ write_metapage(mp);
+
+ return (0);
+}
+
+
+/*
+ * NAME: dbSplit()
+ *
+ * FUNCTION: update the leaf of a dmtree with a new value, splitting
+ * the leaf from the binary buddy system of the dmtree's
+ * leaves, as required.
+ *
+ * PARAMETERS:
+ * tp - pointer to the tree containing the leaf.
+ * leafno - the number of the leaf to be updated.
+ * splitsz - the size the binary buddy system starting at the leaf
+ * must be split to, specified as the log2 number of blocks.
+ * newval - the new value for the leaf.
+ *
+ * RETURN VALUES: none
+ *
+ * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
+{
+ int budsz;
+ int cursz;
+ s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
+
+ /* check if the leaf needs to be split.
+ */
+ if (leaf[leafno] > tp->dmt_budmin) {
+ /* the split occurs by cutting the buddy system in half
+ * at the specified leaf until we reach the specified
+ * size. pick up the starting split size (current size
+ * - 1 in l2) and the corresponding buddy size.
+ */
+ cursz = leaf[leafno] - 1;
+ budsz = BUDSIZE(cursz, tp->dmt_budmin);
+
+ /* split until we reach the specified size.
+ */
+ while (cursz >= splitsz) {
+ /* update the buddy's leaf with its new value.
+ */
+ dbAdjTree(tp, leafno ^ budsz, cursz);
+
+ /* on to the next size and buddy.
+ */
+ cursz -= 1;
+ budsz >>= 1;
+ }
+ }
+
+ /* adjust the dmap tree to reflect the specified leaf's new
+ * value.
+ */
+ dbAdjTree(tp, leafno, newval);
+}
+
+
+/*
+ * NAME: dbBackSplit()
+ *
+ * FUNCTION: back split the binary buddy system of dmtree leaves
+ * that hold a specified leaf until the specified leaf
+ * starts its own binary buddy system.
+ *
+ * the allocators typically perform allocations at the start
+ * of binary buddy systems and dbSplit() is used to accomplish
+ * any required splits. in some cases, however, allocation
+ * may occur in the middle of a binary system and requires a
+ * back split, with the split proceeding out from the middle of
+ * the system (less efficient) rather than the start of the
+ * system (more efficient). the cases in which a back split
+ * is required are rare and are limited to the first allocation
+ * within an allocation group which is a part (not first part)
+ * of a larger binary buddy system and a few exception cases
+ * in which a previous join operation must be backed out.
+ *
+ * PARAMETERS:
+ * tp - pointer to the tree containing the leaf.
+ * leafno - the number of the leaf to be updated.
+ *
+ * RETURN VALUES: none
+ *
+ * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
+ */
+static void dbBackSplit(dmtree_t * tp, int leafno)
+{
+ int budsz, bud, w, bsz, size;
+ int cursz;
+ s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
+
+ /* leaf should be part (not first part) of a binary
+ * buddy system.
+ */
+ assert(leaf[leafno] == NOFREE);
+
+ /* the back split is accomplished by iteratively finding the leaf
+ * that starts the buddy system that contains the specified leaf and
+ * splitting that system in two. this iteration continues until
+ * the specified leaf becomes the start of a buddy system.
+ *
+ * determine maximum possible l2 size for the specified leaf.
+ */
+ size =
+ LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
+ tp->dmt_budmin);
+
+ /* determine the number of leaves covered by this size. this
+ * is the buddy size that we will start with as we search for
+ * the buddy system that contains the specified leaf.
+ */
+ budsz = BUDSIZE(size, tp->dmt_budmin);
+
+ /* back split.
+ */
+ while (leaf[leafno] == NOFREE) {
+ /* find the leftmost buddy leaf.
+ */
+ for (w = leafno, bsz = budsz;; bsz <<= 1,
+ w = (w < bud) ? w : bud) {
+ assert(bsz < le32_to_cpu(tp->dmt_nleafs));
+
+ /* determine the buddy.
+ */
+ bud = w ^ bsz;
+
+ /* check if this buddy is the start of the system.
+ */
+ if (leaf[bud] != NOFREE) {
+ /* split the leaf at the start of the
+ * system in two.
+ */
+ cursz = leaf[bud] - 1;
+ dbSplit(tp, bud, cursz, cursz);
+ break;
+ }
+ }
+ }
+
+ assert(leaf[leafno] == size);
+}
+
+
+/*
+ * NAME: dbJoin()
+ *
+ * FUNCTION: update the leaf of a dmtree with a new value, joining
+ * the leaf with other leaves of the dmtree into a multi-leaf
+ * binary buddy system, as required.
+ *
+ * PARAMETERS:
+ * tp - pointer to the tree containing the leaf.
+ * leafno - the number of the leaf to be updated.
+ * newval - the new value for the leaf.
+ *
+ * RETURN VALUES: none
+ */
+static void dbJoin(dmtree_t * tp, int leafno, int newval)
+{
+ int budsz, buddy;
+ s8 *leaf;
+
+ /* can the new leaf value require a join with other leaves ?
+ */
+ if (newval >= tp->dmt_budmin) {
+ /* pickup a pointer to the leaves of the tree.
+ */
+ leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
+
+ /* try to join the specified leaf into a large binary
+ * buddy system. the join proceeds by attempting to join
+ * the specified leafno with its buddy (leaf) at new value.
+ * if the join occurs, we attempt to join the left leaf
+ * of the joined buddies with its buddy at new value + 1.
+ * we continue to join until we find a buddy that cannot be
+ * joined (does not have a value equal to the size of the
+ * last join) or until all leaves have been joined into a
+ * single system.
+ *
+ * get the buddy size (number of words covered) of
+ * the new value.
+ */
+ budsz = BUDSIZE(newval, tp->dmt_budmin);
+
+ /* try to join.
+ */
+ while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
+ /* get the buddy leaf.
+ */
+ buddy = leafno ^ budsz;
+
+ /* if the leaf's new value is greater than its
+ * buddy's value, we join no more.
+ */
+ if (newval > leaf[buddy])
+ break;
+
+ assert(newval == leaf[buddy]);
+
+ /* check which (leafno or buddy) is the left buddy.
+ * the left buddy gets to claim the blocks resulting
+ * from the join while the right gets to claim none.
+ * the left buddy is also eligable to participate in
+ * a join at the next higher level while the right
+ * is not.
+ *
+ */
+ if (leafno < buddy) {
+ /* leafno is the left buddy.
+ */
+ dbAdjTree(tp, buddy, NOFREE);
+ } else {
+ /* buddy is the left buddy and becomes
+ * leafno.
+ */
+ dbAdjTree(tp, leafno, NOFREE);
+ leafno = buddy;
+ }
+
+ /* on to try the next join.
+ */
+ newval += 1;
+ budsz <<= 1;
+ }
+ }
+
+ /* update the leaf value.
+ */
+ dbAdjTree(tp, leafno, newval);
+}
+
+
+/*
+ * NAME: dbAdjTree()
+ *
+ * FUNCTION: update a leaf of a dmtree with a new value, adjusting
+ * the dmtree, as required, to reflect the new leaf value.
+ * the combination of any buddies must already be done before
+ * this is called.
+ *
+ * PARAMETERS:
+ * tp - pointer to the tree to be adjusted.
+ * leafno - the number of the leaf to be updated.
+ * newval - the new value for the leaf.
+ *
+ * RETURN VALUES: none
+ */
+static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
+{
+ int lp, pp, k;
+ int max;
+
+ /* pick up the index of the leaf for this leafno.
+ */
+ lp = leafno + le32_to_cpu(tp->dmt_leafidx);
+
+ /* is the current value the same as the old value ? if so,
+ * there is nothing to do.
+ */
+ if (tp->dmt_stree[lp] == newval)
+ return;
+
+ /* set the new value.
+ */
+ tp->dmt_stree[lp] = newval;
+
+ /* bubble the new value up the tree as required.
+ */
+ for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
+ /* get the index of the first leaf of the 4 leaf
+ * group containing the specified leaf (leafno).
+ */
+ lp = ((lp - 1) & ~0x03) + 1;
+
+ /* get the index of the parent of this 4 leaf group.
+ */
+ pp = (lp - 1) >> 2;
+
+ /* determine the maximum of the 4 leaves.
+ */
+ max = TREEMAX(&tp->dmt_stree[lp]);
+
+ /* if the maximum of the 4 is the same as the
+ * parent's value, we're done.
+ */
+ if (tp->dmt_stree[pp] == max)
+ break;
+
+ /* parent gets new value.
+ */
+ tp->dmt_stree[pp] = max;
+
+ /* parent becomes leaf for next go-round.
+ */
+ lp = pp;
+ }
+}
+
+
+/*
+ * NAME: dbFindLeaf()
+ *
+ * FUNCTION: search a dmtree_t for sufficient free blocks, returning
+ * the index of a leaf describing the free blocks if
+ * sufficient free blocks are found.
+ *
+ * the search starts at the top of the dmtree_t tree and
+ * proceeds down the tree to the leftmost leaf with sufficient
+ * free space.
+ *
+ * PARAMETERS:
+ * tp - pointer to the tree to be searched.
+ * l2nb - log2 number of free blocks to search for.
+ * leafidx - return pointer to be set to the index of the leaf
+ * describing at least l2nb free blocks if sufficient
+ * free blocks are found.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * ENOSPC - insufficient free blocks.
+ */
+static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
+{
+ int ti, n = 0, k, x = 0;
+
+ /* first check the root of the tree to see if there is
+ * sufficient free space.
+ */
+ if (l2nb > tp->dmt_stree[ROOT])
+ return (ENOSPC);
+
+ /* sufficient free space available. now search down the tree
+ * starting at the next level for the leftmost leaf that
+ * describes sufficient free space.
+ */
+ for (k = le32_to_cpu(tp->dmt_height), ti = 1;
+ k > 0; k--, ti = ((ti + n) << 2) + 1) {
+ /* search the four nodes at this level, starting from
+ * the left.
+ */
+ for (x = ti, n = 0; n < 4; n++) {
+ /* sufficient free space found. move to the next
+ * level (or quit if this is the last level).
+ */
+ if (l2nb <= tp->dmt_stree[x + n])
+ break;
+ }
+
+ /* better have found something since the higher
+ * levels of the tree said it was here.
+ */
+ assert(n < 4);
+ }
+
+ /* set the return to the leftmost leaf describing sufficient
+ * free space.
+ */
+ *leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
+
+ return (0);
+}
+
+
+/*
+ * NAME: dbFindBits()
+ *
+ * FUNCTION: find a specified number of binary buddy free bits within a
+ * dmap bitmap word value.
+ *
+ * this routine searches the bitmap value for (1 << l2nb) free
+ * bits at (1 << l2nb) alignments within the value.
+ *
+ * PARAMETERS:
+ * word - dmap bitmap word value.
+ * l2nb - number of free bits specified as a log2 number.
+ *
+ * RETURN VALUES:
+ * starting bit number of free bits.
+ */
+static int dbFindBits(u32 word, int l2nb)
+{
+ int bitno, nb;
+ u32 mask;
+
+ /* get the number of bits.
+ */
+ nb = 1 << l2nb;
+ assert(nb <= DBWORD);
+
+ /* complement the word so we can use a mask (i.e. 0s represent
+ * free bits) and compute the mask.
+ */
+ word = ~word;
+ mask = ONES << (DBWORD - nb);
+
+ /* scan the word for nb free bits at nb alignments.
+ */
+ for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
+ if ((mask & word) == mask)
+ break;
+ }
+
+ ASSERT(bitno < 32);
+
+ /* return the bit number.
+ */
+ return (bitno);
+}
+
+
+/*
+ * NAME: dbMaxBud(u8 *cp)
+ *
+ * FUNCTION: determine the largest binary buddy string of free
+ * bits within 32-bits of the map.
+ *
+ * PARAMETERS:
+ * cp - pointer to the 32-bit value.
+ *
+ * RETURN VALUES:
+ * largest binary buddy of free bits within a dmap word.
+ */
+static int dbMaxBud(u8 * cp)
+{
+ signed char tmp1, tmp2;
+
+ /* check if the wmap word is all free. if so, the
+ * free buddy size is BUDMIN.
+ */
+ if (*((uint *) cp) == 0)
+ return (BUDMIN);
+
+ /* check if the wmap word is half free. if so, the
+ * free buddy size is BUDMIN-1.
+ */
+ if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
+ return (BUDMIN - 1);
+
+ /* not all free or half free. determine the free buddy
+ * size thru table lookup using quarters of the wmap word.
+ */
+ tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
+ tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
+ return (max(tmp1, tmp2));
+}
+
+
+/*
+ * NAME: cnttz(uint word)
+ *
+ * FUNCTION: determine the number of trailing zeros within a 32-bit
+ * value.
+ *
+ * PARAMETERS:
+ * value - 32-bit value to be examined.
+ *
+ * RETURN VALUES:
+ * count of trailing zeros
+ */
+int cnttz(u32 word)
+{
+ int n;
+
+ for (n = 0; n < 32; n++, word >>= 1) {
+ if (word & 0x01)
+ break;
+ }
+
+ return (n);
+}
+
+
+/*
+ * NAME: cntlz(u32 value)
+ *
+ * FUNCTION: determine the number of leading zeros within a 32-bit
+ * value.
+ *
+ * PARAMETERS:
+ * value - 32-bit value to be examined.
+ *
+ * RETURN VALUES:
+ * count of leading zeros
+ */
+int cntlz(u32 value)
+{
+ int n;
+
+ for (n = 0; n < 32; n++, value <<= 1) {
+ if (value & HIGHORDER)
+ break;
+ }
+ return (n);
+}
+
+
+/*
+ * NAME: blkstol2(s64 nb)
+ *
+ * FUNCTION: convert a block count to its log2 value. if the block
+ * count is not a l2 multiple, it is rounded up to the next
+ * larger l2 multiple.
+ *
+ * PARAMETERS:
+ * nb - number of blocks
+ *
+ * RETURN VALUES:
+ * log2 number of blocks
+ */
+int blkstol2(s64 nb)
+{
+ int l2nb;
+ s64 mask; /* meant to be signed */
+
+ mask = (s64) 1 << (64 - 1);
+
+ /* count the leading bits.
+ */
+ for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
+ /* leading bit found.
+ */
+ if (nb & mask) {
+ /* determine the l2 value.
+ */
+ l2nb = (64 - 1) - l2nb;
+
+ /* check if we need to round up.
+ */
+ if (~mask & nb)
+ l2nb++;
+
+ return (l2nb);
+ }
+ }
+ assert(0);
+ return 0; /* fix compiler warning */
+}
+
+
+/*
+ * NAME: fsDirty()
+ *
+ * FUNCTION: xxx
+ *
+ * PARAMETERS:
+ * ipmnt - mount inode
+ *
+ * RETURN VALUES:
+ * none
+ */
+void fsDirty()
+{
+ printk("fsDirty(): bye-bye\n");
+ assert(0);
+}
+
+
+/*
+ * NAME: dbAllocBottomUp()
+ *
+ * FUNCTION: alloc the specified block range from the working block
+ * allocation map.
+ *
+ * the blocks will be alloc from the working map one dmap
+ * at a time.
+ *
+ * PARAMETERS:
+ * ip - pointer to in-core inode;
+ * blkno - starting block number to be freed.
+ * nblocks - number of blocks to be freed.
+ *
+ * RETURN VALUES:
+ * 0 - success
+ * EIO - i/o error
+ */
+int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
+{
+ struct metapage *mp;
+ struct dmap *dp;
+ int nb, rc;
+ s64 lblkno, rem;
+ struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
+ struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
+
+ IREAD_LOCK(ipbmap);
+
+ /* block to be allocated better be within the mapsize. */
+ ASSERT(nblocks <= bmp->db_mapsize - blkno);
+
+ /*
+ * allocate the blocks a dmap at a time.
+ */
+ mp = NULL;
+ for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
+ /* release previous dmap if any */
+ if (mp) {
+ write_metapage(mp);
+ }
+
+ /* get the buffer for the current dmap. */
+ lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
+ mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL) {
+ IREAD_UNLOCK(ipbmap);
+ return (EIO);
+ }
+ dp = (struct dmap *) mp->data;
+
+ /* determine the number of blocks to be allocated from
+ * this dmap.
+ */
+ nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
+
+ DBFREECK(bmp->db_DBmap, bmp->db_mapsize, blkno, nb);
+
+ /* allocate the blocks. */
+ if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
+ release_metapage(mp);
+ IREAD_UNLOCK(ipbmap);
+ return (rc);
+ }
+
+ DBALLOC(bmp->db_DBmap, bmp->db_mapsize, blkno, nb);
+ }
+
+ /* write the last buffer. */
+ write_metapage(mp);
+
+ IREAD_UNLOCK(ipbmap);
+
+ return (0);
+}
+
+
+static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
+ int nblocks)
+{
+ int rc;
+ int dbitno, word, rembits, nb, nwords, wbitno, agno;
+ s8 oldroot, *leaf;
+ struct dmaptree *tp = (struct dmaptree *) & dp->tree;
+
+ /* save the current value of the root (i.e. maximum free string)
+ * of the dmap tree.
+ */
+ oldroot = tp->stree[ROOT];
+
+ /* pick up a pointer to the leaves of the dmap tree */
+ leaf = tp->stree + LEAFIND;
+
+ /* determine the bit number and word within the dmap of the
+ * starting block.
+ */
+ dbitno = blkno & (BPERDMAP - 1);
+ word = dbitno >> L2DBWORD;
+
+ /* block range better be within the dmap */
+ assert(dbitno + nblocks <= BPERDMAP);
+
+ /* allocate the bits of the dmap's words corresponding to the block
+ * range. not all bits of the first and last words may be contained
+ * within the block range. if this is the case, we'll work against
+ * those words (i.e. partial first and/or last) on an individual basis
+ * (a single pass), allocating the bits of interest by hand and
+ * updating the leaf corresponding to the dmap word. a single pass
+ * will be used for all dmap words fully contained within the
+ * specified range. within this pass, the bits of all fully contained
+ * dmap words will be marked as free in a single shot and the leaves
+ * will be updated. a single leaf may describe the free space of
+ * multiple dmap words, so we may update only a subset of the actual
+ * leaves corresponding to the dmap words of the block range.
+ */
+ for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
+ /* determine the bit number within the word and
+ * the number of bits within the word.
+ */
+ wbitno = dbitno & (DBWORD - 1);
+ nb = min(rembits, DBWORD - wbitno);
+
+ /* check if only part of a word is to be allocated.
+ */
+ if (nb < DBWORD) {
+ /* allocate (set to 1) the appropriate bits within
+ * this dmap word.
+ */
+ dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
+ >> wbitno);
+
+ word++;
+ } else {
+ /* one or more dmap words are fully contained
+ * within the block range. determine how many
+ * words and allocate (set to 1) the bits of these
+ * words.
+ */
+ nwords = rembits >> L2DBWORD;
+ memset(&dp->wmap[word], (int) ONES, nwords * 4);
+
+ /* determine how many bits */
+ nb = nwords << L2DBWORD;
+ word += nwords;
+ }
+ }
+
+ /* update the free count for this dmap */
+ dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) - nblocks);
+
+ /* reconstruct summary tree */
+ dbInitDmapTree(dp);
+
+ BMAP_LOCK(bmp);
+
+ /* if this allocation group is completely free,
+ * update the highest active allocation group number
+ * if this allocation group is the new max.
+ */
+ agno = blkno >> bmp->db_agl2size;
+ if (agno > bmp->db_maxag)
+ bmp->db_maxag = agno;
+
+ /* update the free count for the allocation group and map */
+ bmp->db_agfree[agno] -= nblocks;
+ bmp->db_nfree -= nblocks;
+
+ BMAP_UNLOCK(bmp);
+
+ /* if the root has not changed, done. */
+ if (tp->stree[ROOT] == oldroot)
+ return (0);
+
+ /* root changed. bubble the change up to the dmap control pages.
+ * if the adjustment of the upper level control pages fails,
+ * backout the bit allocation (thus making everything consistent).
+ */
+ if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
+ dbFreeBits(bmp, dp, blkno, nblocks);
+
+ return (rc);
+}
+
+
+/*
+ * NAME: dbExtendFS()
+ *
+ * FUNCTION: extend bmap from blkno for nblocks;
+ * dbExtendFS() updates bmap ready for dbAllocBottomUp();
+ *
+ * L2
+ * |
+ * L1---------------------------------L1
+ * | |
+ * L0---------L0---------L0 L0---------L0---------L0
+ * | | | | | |
+ * d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm;
+ * L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
+ *
+ * <---old---><----------------------------extend----------------------->
+ */
+int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
+{
+ struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
+ int nbperpage = sbi->nbperpage;
+ int i, i0 = TRUE, j, j0 = TRUE, k, n;
+ s64 newsize;
+ s64 p;
+ struct metapage *mp, *l2mp, *l1mp, *l0mp;
+ struct dmapctl *l2dcp, *l1dcp, *l0dcp;
+ struct dmap *dp;
+ s8 *l0leaf, *l1leaf, *l2leaf;
+ struct bmap *bmp = sbi->bmap;
+ int agno, l2agsize, oldl2agsize;
+ s64 ag_rem;
+
+ newsize = blkno + nblocks;
+
+ jEVENT(0, ("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld\n",
+ (long long) blkno, (long long) nblocks,
+ (long long) newsize));
+
+ /*
+ * initialize bmap control page.
+ *
+ * all the data in bmap control page should exclude
+ * the mkfs hidden dmap page.
+ */
+
+ /* update mapsize */
+ bmp->db_mapsize = newsize;
+ bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
+
+ /* compute new AG size */
+ l2agsize = dbGetL2AGSize(newsize);
+ oldl2agsize = bmp->db_agl2size;
+
+ bmp->db_agl2size = l2agsize;
+ bmp->db_agsize = 1 << l2agsize;
+
+ /* compute new number of AG */
+ agno = bmp->db_numag;
+ bmp->db_numag = newsize >> l2agsize;
+ bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
+
+ /*
+ * reconfigure db_agfree[]
+ * from old AG configuration to new AG configuration;
+ *
+ * coalesce contiguous k (newAGSize/oldAGSize) AGs;
+ * i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
+ * note: new AG size = old AG size * (2**x).
+ */
+ if (l2agsize == oldl2agsize)
+ goto extend;
+ k = 1 << (l2agsize - oldl2agsize);
+ ag_rem = bmp->db_agfree[0]; /* save agfree[0] */
+ for (i = 0, n = 0; i < agno; n++) {
+ bmp->db_agfree[n] = 0; /* init collection point */
+
+ /* coalesce cotiguous k AGs; */
+ for (j = 0; j < k && i < agno; j++, i++) {
+ /* merge AGi to AGn */
+ bmp->db_agfree[n] += bmp->db_agfree[i];
+ }
+ }
+ bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */
+
+ for (; n < MAXAG; n++)
+ bmp->db_agfree[n] = 0;
+
+ /*
+ * update highest active ag number
+ */
+
+ bmp->db_maxag = bmp->db_maxag / k;
+
+ /*
+ * extend bmap
+ *
+ * update bit maps and corresponding level control pages;
+ * global control page db_nfree, db_agfree[agno], db_maxfreebud;
+ */
+ extend:
+ /* get L2 page */
+ p = BMAPBLKNO + nbperpage; /* L2 page */
+ l2mp = read_metapage(ipbmap, p, PSIZE, 0);
+ assert(l2mp);
+ l2dcp = (struct dmapctl *) l2mp->data;
+
+ /* compute start L1 */
+ k = blkno >> L2MAXL1SIZE;
+ l2leaf = l2dcp->stree + CTLLEAFIND + k;
+ p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */
+
+ /*
+ * extend each L1 in L2
+ */
+ for (; k < LPERCTL; k++, p += nbperpage) {
+ /* get L1 page */
+ if (j0) {
+ /* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
+ l1mp = read_metapage(ipbmap, p, PSIZE, 0);
+ if (l1mp == NULL)
+ goto errout;
+ l1dcp = (struct dmapctl *) l1mp->data;
+
+ /* compute start L0 */
+ j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
+ l1leaf = l1dcp->stree + CTLLEAFIND + j;
+ p = BLKTOL0(blkno, sbi->l2nbperpage);
+ j0 = FALSE;
+ } else {
+ /* assign/init L1 page */
+ l1mp = get_metapage(ipbmap, p, PSIZE, 0);
+ if (l1mp == NULL)
+ goto errout;
+
+ l1dcp = (struct dmapctl *) l1mp->data;
+
+ /* compute start L0 */
+ j = 0;
+ l1leaf = l1dcp->stree + CTLLEAFIND;
+ p += nbperpage; /* 1st L0 of L1.k */
+ }
+
+ /*
+ * extend each L0 in L1
+ */
+ for (; j < LPERCTL; j++) {
+ /* get L0 page */
+ if (i0) {
+ /* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
+
+ l0mp = read_metapage(ipbmap, p, PSIZE, 0);
+ if (l0mp == NULL)
+ goto errout;
+ l0dcp = (struct dmapctl *) l0mp->data;
+
+ /* compute start dmap */
+ i = (blkno & (MAXL0SIZE - 1)) >>
+ L2BPERDMAP;
+ l0leaf = l0dcp->stree + CTLLEAFIND + i;
+ p = BLKTODMAP(blkno,
+ sbi->l2nbperpage);
+ i0 = FALSE;
+ } else {
+ /* assign/init L0 page */
+ l0mp = get_metapage(ipbmap, p, PSIZE, 0);
+ if (l0mp == NULL)
+ goto errout;
+
+ l0dcp = (struct dmapctl *) l0mp->data;
+
+ /* compute start dmap */
+ i = 0;
+ l0leaf = l0dcp->stree + CTLLEAFIND;
+ p += nbperpage; /* 1st dmap of L0.j */
+ }
+
+ /*
+ * extend each dmap in L0
+ */
+ for (; i < LPERCTL; i++) {
+ /*
+ * reconstruct the dmap page, and
+ * initialize corresponding parent L0 leaf
+ */
+ if ((n = blkno & (BPERDMAP - 1))) {
+ /* read in dmap page: */
+ mp = read_metapage(ipbmap, p,
+ PSIZE, 0);
+ if (mp == NULL)
+ goto errout;
+ n = min(nblocks, (s64)BPERDMAP - n);
+ } else {
+ /* assign/init dmap page */
+ mp = read_metapage(ipbmap, p,
+ PSIZE, 0);
+ if (mp == NULL)
+ goto errout;
+
+ n = min(nblocks, (s64)BPERDMAP);
+ }
+
+ dp = (struct dmap *) mp->data;
+ *l0leaf = dbInitDmap(dp, blkno, n);
+
+ bmp->db_nfree += n;
+ agno = le64_to_cpu(dp->start) >> l2agsize;
+ bmp->db_agfree[agno] += n;
+
+ write_metapage(mp);
+
+ l0leaf++;
+ p += nbperpage;
+
+ blkno += n;
+ nblocks -= n;
+ if (nblocks == 0)
+ break;
+ } /* for each dmap in a L0 */
+
+ /*
+ * build current L0 page from its leaves, and
+ * initialize corresponding parent L1 leaf
+ */
+ *l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
+ write_metapage(l0mp);
+
+ if (nblocks)
+ l1leaf++; /* continue for next L0 */
+ else {
+ /* more than 1 L0 ? */
+ if (j > 0)
+ break; /* build L1 page */
+ else {
+ /* summarize in global bmap page */
+ bmp->db_maxfreebud = *l1leaf;
+ release_metapage(l1mp);
+ release_metapage(l2mp);
+ goto finalize;
+ }
+ }
+ } /* for each L0 in a L1 */
+
+ /*
+ * build current L1 page from its leaves, and
+ * initialize corresponding parent L2 leaf
+ */
+ *l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
+ write_metapage(l1mp);
+
+ if (nblocks)
+ l2leaf++; /* continue for next L1 */
+ else {
+ /* more than 1 L1 ? */
+ if (k > 0)
+ break; /* build L2 page */
+ else {
+ /* summarize in global bmap page */
+ bmp->db_maxfreebud = *l2leaf;
+ release_metapage(l2mp);
+ goto finalize;
+ }
+ }
+ } /* for each L1 in a L2 */
+
+ assert(0);
+
+ /*
+ * finalize bmap control page
+ */
+ finalize:
+
+ return 0;
+
+ errout:
+ return EIO;
+}
+
+
+/*
+ * dbFinalizeBmap()
+ */
+void dbFinalizeBmap(struct inode *ipbmap)
+{
+ struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
+ int actags, inactags, l2nl;
+ s64 ag_rem, actfree, inactfree, avgfree;
+ int i, n;
+
+ /*
+ * finalize bmap control page
+ */
+//finalize:
+ /*
+ * compute db_agpref: preferred ag to allocate from
+ * (the leftmost ag with average free space in it);
+ */
+//agpref:
+ /* get the number of active ags and inacitve ags */
+ actags = bmp->db_maxag + 1;
+ inactags = bmp->db_numag - actags;
+ ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */
+
+ /* determine how many blocks are in the inactive allocation
+ * groups. in doing this, we must account for the fact that
+ * the rightmost group might be a partial group (i.e. file
+ * system size is not a multiple of the group size).
+ */
+ inactfree = (inactags && ag_rem) ?
+ ((inactags - 1) << bmp->db_agl2size) + ag_rem
+ : inactags << bmp->db_agl2size;
+
+ /* determine how many free blocks are in the active
+ * allocation groups plus the average number of free blocks
+ * within the active ags.
+ */
+ actfree = bmp->db_nfree - inactfree;
+ avgfree = (u32) actfree / (u32) actags;
+
+ /* if the preferred allocation group has not average free space.
+ * re-establish the preferred group as the leftmost
+ * group with average free space.
+ */
+ if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
+ for (bmp->db_agpref = 0; bmp->db_agpref < actags;
+ bmp->db_agpref++) {
+ if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
+ break;
+ }
+ assert(bmp->db_agpref < bmp->db_numag);
+ }
+
+ /*
+ * compute db_aglevel, db_agheigth, db_width, db_agstart:
+ * an ag is covered in aglevel dmapctl summary tree,
+ * at agheight level height (from leaf) with agwidth number of nodes
+ * each, which starts at agstart index node of the smmary tree node
+ * array;
+ */
+ bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
+ l2nl =
+ bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
+ bmp->db_agheigth = l2nl >> 1;
+ bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheigth << 1));
+ for (i = 5 - bmp->db_agheigth, bmp->db_agstart = 0, n = 1; i > 0;
+ i--) {
+ bmp->db_agstart += n;
+ n <<= 2;
+ }
+
+/*
+printk("bmap: agpref:%d aglevel:%d agheigth:%d agwidth:%d\n",
+ bmp->db_agpref, bmp->db_aglevel, bmp->db_agheigth, bmp->db_agwidth);
+*/
+}
+
+
+/*
+ * NAME: dbInitDmap()/ujfs_idmap_page()
+ *
+ * FUNCTION: initialize working/persistent bitmap of the dmap page
+ * for the specified number of blocks:
+ *
+ * at entry, the bitmaps had been initialized as free (ZEROS);
+ * The number of blocks will only account for the actually
+ * existing blocks. Blocks which don't actually exist in
+ * the aggregate will be marked as allocated (ONES);
+ *
+ * PARAMETERS:
+ * dp - pointer to page of map
+ * nblocks - number of blocks this page
+ *
+ * RETURNS: NONE
+ */
+static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
+{
+ int blkno, w, b, r, nw, nb, i;
+/*
+printk("sbh_dmap: in dbInitDmap blkno:%Ld nblocks:%ld\n", Blkno, nblocks);
+*/
+
+ /* starting block number within the dmap */
+ blkno = Blkno & (BPERDMAP - 1);
+
+ if (blkno == 0) {
+ dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
+ dp->start = cpu_to_le64(Blkno);
+
+ if (nblocks == BPERDMAP) {
+ memset(&dp->wmap[0], 0, LPERDMAP * 4);
+ memset(&dp->pmap[0], 0, LPERDMAP * 4);
+ goto initTree;
+ }
+ } else {
+ dp->nblocks =
+ cpu_to_le32(le32_to_cpu(dp->nblocks) + nblocks);
+ dp->nfree = cpu_to_le32(le32_to_cpu(dp->nfree) + nblocks);
+ }
+
+ /* word number containing start block number */
+ w = blkno >> L2DBWORD;
+
+ /*
+ * free the bits corresponding to the block range (ZEROS):
+ * note: not all bits of the first and last words may be contained
+ * within the block range.
+ */
+ for (r = nblocks; r > 0; r -= nb, blkno += nb) {
+ /* number of bits preceding range to be freed in the word */
+ b = blkno & (DBWORD - 1);
+ /* number of bits to free in the word */
+ nb = min(r, DBWORD - b);
+
+ /* is partial word to be freed ? */
+ if (nb < DBWORD) {
+ /* free (set to 0) from the bitmap word */
+ dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
+ >> b));
+ dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
+ >> b));
+
+ /* skip the word freed */
+ w++;
+ } else {
+ /* free (set to 0) contiguous bitmap words */
+ nw = r >> L2DBWORD;
+ memset(&dp->wmap[w], 0, nw * 4);
+ memset(&dp->pmap[w], 0, nw * 4);
+
+ /* skip the words freed */
+ nb = nw << L2DBWORD;
+ w += nw;
+ }
+ }
+
+ /*
+ * mark bits following the range to be freed (non-existing
+ * blocks) as allocated (ONES)
+ */
+/*
+printk("sbh_dmap: in dbInitDmap, preparing to mark unbacked, blkno:%ld nblocks:%ld\n",
+ blkno, nblocks);
+*/
+
+ if (blkno == BPERDMAP)
+ goto initTree;
+
+ /* the first word beyond the end of existing blocks */
+ w = blkno >> L2DBWORD;
+
+ /* does nblocks fall on a 32-bit boundary ? */
+ b = blkno & (DBWORD - 1);
+/*
+printk("sbh_dmap: in dbInitDmap, b:%ld w:%ld mask: %lx\n", b, w, (ONES>>b));
+*/
+ if (b) {
+ /* mark a partial word allocated */
+ dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
+ w++;
+ }
+
+ /* set the rest of the words in the page to allocated (ONES) */
+ for (i = w; i < LPERDMAP; i++)
+ dp->pmap[i] = dp->wmap[i] = ONES;
+
+ /*
+ * init tree
+ */
+ initTree:
+ return (dbInitDmapTree(dp));
+}
+
+
+/*
+ * NAME: dbInitDmapTree()/ujfs_complete_dmap()
+ *
+ * FUNCTION: initialize summary tree of the specified dmap:
+ *
+ * at entry, bitmap of the dmap has been initialized;
+ *
+ * PARAMETERS:
+ * dp - dmap to complete
+ * blkno - starting block number for this dmap
+ * treemax - will be filled in with max free for this dmap
+ *
+ * RETURNS: max free string at the root of the tree
+ */
+static int dbInitDmapTree(struct dmap * dp)
+{
+ struct dmaptree *tp;
+ s8 *cp;
+ int i;
+
+ /* init fixed info of tree */
+ tp = &dp->tree;
+ tp->nleafs = cpu_to_le32(LPERDMAP);
+ tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
+ tp->leafidx = cpu_to_le32(LEAFIND);
+ tp->height = cpu_to_le32(4);
+ tp->budmin = BUDMIN;
+
+ /* init each leaf from corresponding wmap word:
+ * note: leaf is set to NOFREE(-1) if all blocks of corresponding
+ * bitmap word are allocated.
+ */
+ cp = tp->stree + le32_to_cpu(tp->leafidx);
+ for (i = 0; i < LPERDMAP; i++)
+ *cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
+
+ /* build the dmap's binary buddy summary tree */
+ return (dbInitTree(tp));
+}
+
+
+/*
+ * NAME: dbInitTree()/ujfs_adjtree()
+ *
+ * FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl.
+ *
+ * at entry, the leaves of the tree has been initialized
+ * from corresponding bitmap word or root of summary tree
+ * of the child control page;
+ * configure binary buddy system at the leaf level, then
+ * bubble up the values of the leaf nodes up the tree.
+ *
+ * PARAMETERS:
+ * cp - Pointer to the root of the tree
+ * l2leaves- Number of leaf nodes as a power of 2
+ * l2min - Number of blocks that can be covered by a leaf
+ * as a power of 2
+ *
+ * RETURNS: max free string at the root of the tree
+ */
+static int dbInitTree(struct dmaptree * dtp)
+{
+ int l2max, l2free, bsize, nextb, i;
+ int child, parent, nparent;
+ s8 *tp, *cp, *cp1;
+
+ tp = dtp->stree;
+
+ /* Determine the maximum free string possible for the leaves */
+ l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
+
+ /*
+ * configure the leaf levevl into binary buddy system
+ *
+ * Try to combine buddies starting with a buddy size of 1
+ * (i.e. two leaves). At a buddy size of 1 two buddy leaves
+ * can be combined if both buddies have a maximum free of l2min;
+ * the combination will result in the left-most buddy leaf having
+ * a maximum free of l2min+1.
+ * After processing all buddies for a given size, process buddies
+ * at the next higher buddy size (i.e. current size * 2) and
+ * the next maximum free (current free + 1).
+ * This continues until the maximum possible buddy combination
+ * yields maximum free.
+ */
+ for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
+ l2free++, bsize = nextb) {
+ /* get next buddy size == current buddy pair size */
+ nextb = bsize << 1;
+
+ /* scan each adjacent buddy pair at current buddy size */
+ for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
+ i < le32_to_cpu(dtp->nleafs);
+ i += nextb, cp += nextb) {
+ /* coalesce if both adjacent buddies are max free */
+ if (*cp == l2free && *(cp + bsize) == l2free) {
+ *cp = l2free + 1; /* left take right */
+ *(cp + bsize) = -1; /* right give left */
+ }
+ }
+ }
+
+ /*
+ * bubble summary information of leaves up the tree.
+ *
+ * Starting at the leaf node level, the four nodes described by
+ * the higher level parent node are compared for a maximum free and
+ * this maximum becomes the value of the parent node.
+ * when all lower level nodes are processed in this fashion then
+ * move up to the next level (parent becomes a lower level node) and
+ * continue the process for that level.
+ */
+ for (child = le32_to_cpu(dtp->leafidx),
+ nparent = le32_to_cpu(dtp->nleafs) >> 2;
+ nparent > 0; nparent >>= 2, child = parent) {
+ /* get index of 1st node of parent level */
+ parent = (child - 1) >> 2;
+
+ /* set the value of the parent node as the maximum
+ * of the four nodes of the current level.
+ */
+ for (i = 0, cp = tp + child, cp1 = tp + parent;
+ i < nparent; i++, cp += 4, cp1++)
+ *cp1 = TREEMAX(cp);
+ }
+
+ return (*tp);
+}
+
+
+/*
+ * dbInitDmapCtl()
+ *
+ * function: initialize dmapctl page
+ */
+static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
+{ /* start leaf index not covered by range */
+ s8 *cp;
+
+ dcp->nleafs = cpu_to_le32(LPERCTL);
+ dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
+ dcp->leafidx = cpu_to_le32(CTLLEAFIND);
+ dcp->height = cpu_to_le32(5);
+ dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
+
+ /*
+ * initialize the leaves of current level that were not covered
+ * by the specified input block range (i.e. the leaves have no
+ * low level dmapctl or dmap).
+ */
+ cp = &dcp->stree[CTLLEAFIND + i];
+ for (; i < LPERCTL; i++)
+ *cp++ = NOFREE;
+
+ /* build the dmap's binary buddy summary tree */
+ return (dbInitTree((struct dmaptree *) dcp));
+}
+
+
+/*
+ * NAME: dbGetL2AGSize()/ujfs_getagl2size()
+ *
+ * FUNCTION: Determine log2(allocation group size) from aggregate size
+ *
+ * PARAMETERS:
+ * nblocks - Number of blocks in aggregate
+ *
+ * RETURNS: log2(allocation group size) in aggregate blocks
+ */
+static int dbGetL2AGSize(s64 nblocks)
+{
+ s64 sz;
+ s64 m;
+ int l2sz;
+
+ if (nblocks < BPERDMAP * MAXAG)
+ return (L2BPERDMAP);
+
+ /* round up aggregate size to power of 2 */
+ m = ((u64) 1 << (64 - 1));
+ for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
+ if (m & nblocks)
+ break;
+ }
+
+ sz = (s64) 1 << l2sz;
+ if (sz < nblocks)
+ l2sz += 1;
+
+ /* agsize = roundupSize/max_number_of_ag */
+ return (l2sz - L2MAXAG);
+}
+
+
+/*
+ * NAME: dbMapFileSizeToMapSize()
+ *
+ * FUNCTION: compute number of blocks the block allocation map file
+ * can cover from the map file size;
+ *
+ * RETURNS: Number of blocks which can be covered by this block map file;
+ */
+
+/*
+ * maximum number of map pages at each level including control pages
+ */
+#define MAXL0PAGES (1 + LPERCTL)
+#define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES)
+#define MAXL2PAGES (1 + LPERCTL * MAXL1PAGES)
+
+/*
+ * convert number of map pages to the zero origin top dmapctl level
+ */
+#define BMAPPGTOLEV(npages) \
+ (((npages) <= 3 + MAXL0PAGES) ? 0 \
+ : ((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
+
+s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
+{
+ struct super_block *sb = ipbmap->i_sb;
+ s64 nblocks;
+ s64 npages, ndmaps;
+ int level, i;
+ int complete, factor;
+
+ nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
+ npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
+ level = BMAPPGTOLEV(npages);
+
+ /* At each level, accumulate the number of dmap pages covered by
+ * the number of full child levels below it;
+ * repeat for the last incomplete child level.
+ */
+ ndmaps = 0;
+ npages--; /* skip the first global control page */
+ /* skip higher level control pages above top level covered by map */
+ npages -= (2 - level);
+ npages--; /* skip top level's control page */
+ for (i = level; i >= 0; i--) {
+ factor =
+ (i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
+ complete = (u32) npages / factor;
+ ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL
+ : ((i == 1) ? LPERCTL : 1));
+
+ /* pages in last/incomplete child */
+ npages = (u32) npages % factor;
+ /* skip incomplete child's level control page */
+ npages--;
+ }
+
+ /* convert the number of dmaps into the number of blocks
+ * which can be covered by the dmaps;
+ */
+ nblocks = ndmaps << L2BPERDMAP;
+
+ return (nblocks);
+}
+
+
+#ifdef _JFS_DEBUG_DMAP
+/*
+ * DBinitmap()
+ */
+static void DBinitmap(s64 size, struct inode *ipbmap, u32 ** results)
+{
+ int npages;
+ u32 *dbmap, *d;
+ int n;
+ s64 lblkno, cur_block;
+ struct dmap *dp;
+ struct metapage *mp;
+
+ npages = size / 32768;
+ npages += (size % 32768) ? 1 : 0;
+
+ dbmap = (u32 *) xmalloc(npages * 4096, L2PSIZE, kernel_heap);
+ if (dbmap == NULL)
+ assert(0);
+
+ for (n = 0, d = dbmap; n < npages; n++, d += 1024)
+ bzero(d, 4096);
+
+ /* Need to initialize from disk map pages
+ */
+ for (d = dbmap, cur_block = 0; cur_block < size;
+ cur_block += BPERDMAP, d += LPERDMAP) {
+ lblkno = BLKTODMAP(cur_block,
+ JFS_SBI(ipbmap->i_sb)->bmap->
+ db_l2nbperpage);
+ mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
+ if (mp == NULL) {
+ assert(0);
+ }
+ dp = (struct dmap *) mp->data;
+
+ for (n = 0; n < LPERDMAP; n++)
+ d[n] = le32_to_cpu(dp->wmap[n]);
+
+ release_metapage(mp);
+ }
+
+ *results = dbmap;
+}
+
+
+/*
+ * DBAlloc()
+ */
+void DBAlloc(uint * dbmap, s64 mapsize, s64 blkno, s64 nblocks)
+{
+ int word, nb, bitno;
+ u32 mask;
+
+ assert(blkno > 0 && blkno < mapsize);
+ assert(nblocks > 0 && nblocks <= mapsize);
+
+ assert(blkno + nblocks <= mapsize);
+
+ dbmap += (blkno / 32);
+ while (nblocks > 0) {
+ bitno = blkno & (32 - 1);
+ nb = min(nblocks, 32 - bitno);
+
+ mask = (0xffffffff << (32 - nb) >> bitno);
+ assert((mask & *dbmap) == 0);
+ *dbmap |= mask;
+
+ dbmap++;
+ blkno += nb;
+ nblocks -= nb;
+ }
+}
+
+
+/*
+ * DBFree()
+ */
+static void DBFree(uint * dbmap, s64 mapsize, s64 blkno, s64 nblocks)
+{
+ int word, nb, bitno;
+ u32 mask;
+
+ assert(blkno > 0 && blkno < mapsize);
+ assert(nblocks > 0 && nblocks <= mapsize);
+
+ assert(blkno + nblocks <= mapsize);
+
+ dbmap += (blkno / 32);
+ while (nblocks > 0) {
+ bitno = blkno & (32 - 1);
+ nb = min(nblocks, 32 - bitno);
+
+ mask = (0xffffffff << (32 - nb) >> bitno);
+ assert((mask & *dbmap) == mask);
+ *dbmap &= ~mask;
+
+ dbmap++;
+ blkno += nb;
+ nblocks -= nb;
+ }
+}
+
+
+/*
+ * DBAllocCK()
+ */
+static void DBAllocCK(uint * dbmap, s64 mapsize, s64 blkno, s64 nblocks)
+{
+ int word, nb, bitno;
+ u32 mask;
+
+ assert(blkno > 0 && blkno < mapsize);
+ assert(nblocks > 0 && nblocks <= mapsize);
+
+ assert(blkno + nblocks <= mapsize);
+
+ dbmap += (blkno / 32);
+ while (nblocks > 0) {
+ bitno = blkno & (32 - 1);
+ nb = min(nblocks, 32 - bitno);
+
+ mask = (0xffffffff << (32 - nb) >> bitno);
+ assert((mask & *dbmap) == mask);
+
+ dbmap++;
+ blkno += nb;
+ nblocks -= nb;
+ }
+}
+
+
+/*
+ * DBFreeCK()
+ */
+static void DBFreeCK(uint * dbmap, s64 mapsize, s64 blkno, s64 nblocks)
+{
+ int word, nb, bitno;
+ u32 mask;
+
+ assert(blkno > 0 && blkno < mapsize);
+ assert(nblocks > 0 && nblocks <= mapsize);
+
+ assert(blkno + nblocks <= mapsize);
+
+ dbmap += (blkno / 32);
+ while (nblocks > 0) {
+ bitno = blkno & (32 - 1);
+ nb = min(nblocks, 32 - bitno);
+
+ mask = (0xffffffff << (32 - nb) >> bitno);
+ assert((mask & *dbmap) == 0);
+
+ dbmap++;
+ blkno += nb;
+ nblocks -= nb;
+ }
+}
+
+
+/*
+ * dbPrtMap()
+ */
+static void dbPrtMap(struct bmap * bmp)
+{
+ printk(" mapsize: %d%d\n", bmp->db_mapsize);
+ printk(" nfree: %d%d\n", bmp->db_nfree);
+ printk(" numag: %d\n", bmp->db_numag);
+ printk(" agsize: %d%d\n", bmp->db_agsize);
+ printk(" agl2size: %d\n", bmp->db_agl2size);
+ printk(" agwidth: %d\n", bmp->db_agwidth);
+ printk(" agstart: %d\n", bmp->db_agstart);
+ printk(" agheigth: %d\n", bmp->db_agheigth);
+ printk(" aglevel: %d\n", bmp->db_aglevel);
+ printk(" maxlevel: %d\n", bmp->db_maxlevel);
+ printk(" maxag: %d\n", bmp->db_maxag);
+ printk(" agpref: %d\n", bmp->db_agpref);
+ printk(" l2nbppg: %d\n", bmp->db_l2nbperpage);
+}
+
+
+/*
+ * dbPrtCtl()
+ */
+static void dbPrtCtl(struct dmapctl * dcp)
+{
+ int i, j, n;
+
+ printk(" height: %08x\n", le32_to_cpu(dcp->height));
+ printk(" leafidx: %08x\n", le32_to_cpu(dcp->leafidx));
+ printk(" budmin: %08x\n", dcp->budmin);
+ printk(" nleafs: %08x\n", le32_to_cpu(dcp->nleafs));
+ printk(" l2nleafs: %08x\n", le32_to_cpu(dcp->l2nleafs));
+
+ printk("\n Tree:\n");
+ for (i = 0; i < CTLLEAFIND; i += 8) {
+ n = min(8, CTLLEAFIND - i);
+
+ for (j = 0; j < n; j++)
+ printf(" [%03x]: %02x", i + j,
+ (char) dcp->stree[i + j]);
+ printf("\n");
+ }
+
+ printk("\n Tree Leaves:\n");
+ for (i = 0; i < LPERCTL; i += 8) {
+ n = min(8, LPERCTL - i);
+
+ for (j = 0; j < n; j++)
+ printf(" [%03x]: %02x",
+ i + j,
+ (char) dcp->stree[i + j + CTLLEAFIND]);
+ printf("\n");
+ }
+}
+#endif /* _JFS_DEBUG_DMAP */
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)