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Diffstat (limited to 'fs/jfs/jfs_dmap.c')
| -rw-r--r-- | fs/jfs/jfs_dmap.c | 4100 |
1 files changed, 4100 insertions, 0 deletions
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c new file mode 100644 index 000000000..1014f2a24 --- /dev/null +++ b/fs/jfs/jfs_dmap.c @@ -0,0 +1,4100 @@ +/* + * Copyright (C) International Business Machines Corp., 2000-2004 + * Portions Copyright (C) Tino Reichardt, 2012 + * + * 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 <linux/slab.h> +#include "jfs_incore.h" +#include "jfs_superblock.h" +#include "jfs_dmap.h" +#include "jfs_imap.h" +#include "jfs_lock.h" +#include "jfs_metapage.h" +#include "jfs_debug.h" +#include "jfs_discard.h" + +/* + * 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) mutex_init(&bmp->db_bmaplock) +#define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock) +#define BMAP_UNLOCK(bmp) mutex_unlock(&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 int dbBackSplit(dmtree_t * tp, int leafno); +static int 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); +static 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 int 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); +static int blkstol2(s64 nb); + +static int cntlz(u32 value); +static 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. + */ +static const s8 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 + * -EINVAL - wrong bmap data + */ +int dbMount(struct inode *ipbmap) +{ + struct bmap *bmp; + struct dbmap_disk *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_disk *) 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); + if (!bmp->db_numag) { + release_metapage(mp); + kfree(bmp); + return -EINVAL; + } + + 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_agheight = le32_to_cpu(dbmp_le->dn_agheight); + 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)); + + /* + * 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; + + if (!(mounterror || isReadOnly(ipbmap))) + dbSync(ipbmap); + + /* + * Invalidate the page cache buffers + */ + truncate_inode_pages(ipbmap->i_mapping, 0); + + /* free the memory for the in-memory bmap. */ + kfree(bmp); + + return (0); +} + +/* + * dbSync() + */ +int dbSync(struct inode *ipbmap) +{ + struct dbmap_disk *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) { + jfs_err("dbSync: read_metapage failed!"); + return -EIO; + } + /* copy the in-memory version of the bmap to the on-disk version */ + dbmp_le = (struct dbmap_disk *) 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_agheight = cpu_to_le32(bmp->db_agheight); + 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 + */ + filemap_write_and_wait(ipbmap->i_mapping); + + 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; + struct super_block *sb = ipbmap->i_sb; + + IREAD_LOCK(ipbmap, RDWRLOCK_DMAP); + + /* block to be freed better be within the mapsize. */ + if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) { + IREAD_UNLOCK(ipbmap); + printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n", + (unsigned long long) blkno, + (unsigned long long) nblocks); + jfs_error(ip->i_sb, "block to be freed is outside the map\n"); + return -EIO; + } + + /** + * TRIM the blocks, when mounted with discard option + */ + if (JFS_SBI(sb)->flag & JFS_DISCARD) + if (JFS_SBI(sb)->minblks_trim <= nblocks) + jfs_issue_discard(ipbmap, blkno, nblocks); + + /* + * 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))); + + /* free the blocks. */ + if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) { + jfs_error(ip->i_sb, "error in block map\n"); + release_metapage(mp); + IREAD_UNLOCK(ipbmap); + return (rc); + } + } + + /* write the last buffer. */ + if (mp) + 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; + unsigned long flags; + + /* the blocks better be within the mapsize. */ + if (blkno + nblocks > bmp->db_mapsize) { + printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n", + (unsigned long long) blkno, + (unsigned long long) nblocks); + jfs_error(ipbmap->i_sb, "blocks are outside the map\n"); + return -EIO; + } + + /* 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; + metapage_wait_for_io(mp); + } + 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; + + LOGSYNC_LOCK(log, flags); + 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 */ + list_move(&mp->synclist, &tblk->synclist); + } + + /* inherit younger/larger clsn */ + logdiff(difft, tblk->clsn, log); + logdiff(diffp, mp->clsn, log); + if (difft > diffp) + mp->clsn = tblk->clsn; + } else { + mp->log = log; + mp->lsn = lsn; + + /* insert bp after tblock in logsync list */ + log->count++; + list_add(&mp->synclist, &tblk->synclist); + + mp->clsn = tblk->clsn; + } + LOGSYNC_UNLOCK(log, flags); + } + + /* 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); + + /* 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; + + mapSize = bmp->db_mapsize; + + /* the hint should be within the map */ + if (hint >= mapSize) { + jfs_error(ip->i_sb, "the hint is outside the map\n"); + return -EIO; + } + + /* 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, RDWRLOCK_DMAP); + + rc = dbAllocAny(bmp, nblocks, l2nb, results); + + 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 currently 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, RDWRLOCK_DMAP); + + /* 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; + 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) + 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) + 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, RDWRLOCK_DMAP); + if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC) + goto write_unlock; + + IWRITE_UNLOCK(ipbmap); + + + pref_ag: + /* + * Let dbNextAG recommend a preferred allocation group + */ + agno = dbNextAG(ipbmap); + IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); + + /* 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); + + write_unlock: + IWRITE_UNLOCK(ipbmap); + + return (rc); + + read_unlock: + IREAD_UNLOCK(ipbmap); + + return (rc); +} + +#ifdef _NOTYET +/* + * 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, RDWRLOCK_DMAP); + + /* + * 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) + mark_metapage_dirty(mp); + + release_metapage(mp); + + return (rc); +} +#endif /* _NOTYET */ + +/* + * 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 + */ +static 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, RDWRLOCK_DMAP); + + /* better be within the file system */ + bmp = sbi->bmap; + if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) { + IREAD_UNLOCK(ipbmap); + jfs_error(ip->i_sb, "the block is outside the filesystem\n"); + return -EIO; + } + + /* 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 boundary. + */ + 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; + } + + 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) + write_metapage(mp); + else + /* we were not successful */ + release_metapage(mp); + + 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; + + if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) { + jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n"); + return -EIO; + } + + /* 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_t(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; + + if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) { + jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n"); + return -EIO; + } + + 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. + */ + if (l2nb > bmp->db_agl2size) { + jfs_error(bmp->db_ipbmap->i_sb, + "allocation request is larger than the allocation group size\n"); + return -EIO; + } + + /* 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); + if ((rc == -ENOSPC) && + (bmp->db_agfree[agno] == bmp->db_agsize)) { + printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n", + (unsigned long long) blkno, + (unsigned long long) nblocks); + jfs_error(bmp->db_ipbmap->i_sb, + "dbAllocCtl failed in free AG\n"); + } + 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; + + if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { + jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); + release_metapage(mp); + return -EIO; + } + + /* 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_agheight << 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_agheight; k > 0; k--) { + for (n = 0, m = (ti << 2) + 1; n < 4; n++) { + if (l2nb <= dcp->stree[m + n]) { + ti = m + n; + break; + } + } + if (n == 4) { + jfs_error(bmp->db_ipbmap->i_sb, + "failed descending stree\n"); + release_metapage(mp); + return -EIO; + } + } + + /* 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 dmap that + * contains or starts off the free space. + */ + if ((rc = + dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1, + &blkno))) { + if (rc == -ENOSPC) { + jfs_error(bmp->db_ipbmap->i_sb, + "control page inconsistent\n"); + return -EIO; + } + return (rc); + } + } + + /* allocate the blocks. + */ + rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results); + if (rc == -ENOSPC) { + jfs_error(bmp->db_ipbmap->i_sb, + "unable to allocate blocks\n"); + rc = -EIO; + } + 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); + if (rc == -ENOSPC) { + jfs_error(bmp->db_ipbmap->i_sb, "unable to allocate blocks\n"); + return -EIO; + } + return (rc); +} + + +/* + * NAME: dbDiscardAG() + * + * FUNCTION: attempt to discard (TRIM) all free blocks of specific AG + * + * algorithm: + * 1) allocate blocks, as large as possible and save them + * while holding IWRITE_LOCK on ipbmap + * 2) trim all these saved block/length values + * 3) mark the blocks free again + * + * benefit: + * - we work only on one ag at some time, minimizing how long we + * need to lock ipbmap + * - reading / writing the fs is possible most time, even on + * trimming + * + * downside: + * - we write two times to the dmapctl and dmap pages + * - but for me, this seems the best way, better ideas? + * /TR 2012 + * + * PARAMETERS: + * ip - pointer to in-core inode + * agno - ag to trim + * minlen - minimum value of contiguous blocks + * + * RETURN VALUES: + * s64 - actual number of blocks trimmed + */ +s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen) +{ + struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap; + struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap; + s64 nblocks, blkno; + u64 trimmed = 0; + int rc, l2nb; + struct super_block *sb = ipbmap->i_sb; + + struct range2trim { + u64 blkno; + u64 nblocks; + } *totrim, *tt; + + /* max blkno / nblocks pairs to trim */ + int count = 0, range_cnt; + u64 max_ranges; + + /* prevent others from writing new stuff here, while trimming */ + IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP); + + nblocks = bmp->db_agfree[agno]; + max_ranges = nblocks; + do_div(max_ranges, minlen); + range_cnt = min_t(u64, max_ranges + 1, 32 * 1024); + totrim = kmalloc_array(range_cnt, sizeof(struct range2trim), GFP_NOFS); + if (totrim == NULL) { + jfs_error(bmp->db_ipbmap->i_sb, "no memory for trim array\n"); + IWRITE_UNLOCK(ipbmap); + return 0; + } + + tt = totrim; + while (nblocks >= minlen) { + l2nb = BLKSTOL2(nblocks); + + /* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */ + rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno); + if (rc == 0) { + tt->blkno = blkno; + tt->nblocks = nblocks; + tt++; count++; + + /* the whole ag is free, trim now */ + if (bmp->db_agfree[agno] == 0) + break; + + /* give a hint for the next while */ + nblocks = bmp->db_agfree[agno]; + continue; + } else if (rc == -ENOSPC) { + /* search for next smaller log2 block */ + l2nb = BLKSTOL2(nblocks) - 1; + nblocks = 1LL << l2nb; + } else { + /* Trim any already allocated blocks */ + jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n"); + break; + } + + /* check, if our trim array is full */ + if (unlikely(count >= range_cnt - 1)) + break; + } + IWRITE_UNLOCK(ipbmap); + + tt->nblocks = 0; /* mark the current end */ + for (tt = totrim; tt->nblocks != 0; tt++) { + /* when mounted with online discard, dbFree() will + * call jfs_issue_discard() itself */ + if (!(JFS_SBI(sb)->flag & JFS_DISCARD)) + jfs_issue_discard(ip, tt->blkno, tt->nblocks); + dbFree(ip, tt->blkno, tt->nblocks); + trimmed += tt->nblocks; + } + kfree(totrim); + + return trimmed; +} + +/* + * 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; + + if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { + jfs_error(bmp->db_ipbmap->i_sb, + "Corrupt dmapctl page\n"); + release_metapage(mp); + return -EIO; + } + + /* search the tree within the dmap control page for + * sufficient 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) { + if (lev != level) { + jfs_error(bmp->db_ipbmap->i_sb, + "dmap inconsistent\n"); + return -EIO; + } + 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. + */ + if (dp->tree.stree[ROOT] != L2BPERDMAP) { + release_metapage(mp); + jfs_error(bmp->db_ipbmap->i_sb, + "the dmap is not all free\n"); + rc = -EIO; + goto backout; + } + + /* determine how many blocks to allocate from this dmap. + */ + nb = min_t(s64, n, 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. + */ + jfs_error(bmp->db_ipbmap->i_sb, + "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); + jfs_error(bmp->db_ipbmap->i_sb, "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 = 0, 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 */ + rc = dbFreeBits(bmp, dp, blkno, nblocks); + + /* if error or the root has not changed, done. */ + if (rc || (dp->tree.stree[ROOT] == oldroot)) + return (rc); + + /* 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) { + if (leaf[word] < BUDMIN) { + jfs_error(bmp->db_ipbmap->i_sb, + "leaf page corrupt\n"); + break; + } + + /* 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_t(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 */ + le32_add_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: 0 for success + * + * serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit; + */ +static int 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 rc = 0; + 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. + */ + rc = dbJoin(tp, word, + dbMaxBud((u8 *) & dp->wmap[word])); + if (rc) + return rc; + + 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. + */ + rc = dbJoin(tp, word, size); + if (rc) + return rc; + + /* get the number of dmap words handled. + */ + nw = BUDSIZE(size, BUDMIN); + word += nw; + } + } + } + + /* update the free count for this dmap. + */ + le32_add_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); + + return 0; +} + + +/* + * 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; + + if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) { + jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); + release_metapage(mp); + return -EIO; + } + + /* 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 update + * 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) { + rc = dbBackSplit((dmtree_t *) dcp, leafno); + if (rc) + return rc; + oldval = dcp->stree[ti]; + } + dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval); + } else { + rc = dbJoin((dmtree_t *) dcp, leafno, newval); + if (rc) + return rc; + } + + /* 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); + if (bmp->db_maxfreebud != oldroot) { + jfs_error(bmp->db_ipbmap->i_sb, + "the maximum free buddy is not the old root\n"); + } + 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 int 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) { + if (bsz >= le32_to_cpu(tp->dmt_nleafs)) { + jfs_err("JFS: block map error in dbBackSplit"); + return -EIO; + } + + /* 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; + } + } + } + + if (leaf[leafno] != size) { + jfs_err("JFS: wrong leaf value in dbBackSplit"); + return -EIO; + } + return 0; +} + + +/* + * 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 int 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; + + /* It shouldn't be less */ + if (newval < leaf[buddy]) + return -EIO; + + /* 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 eligible 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); + + return 0; +} + + +/* + * 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 + */ +static 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 + */ +static 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 + */ +static 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: 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, RDWRLOCK_DMAP); + + /* 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))); + + /* allocate the blocks. */ + if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) { + release_metapage(mp); + IREAD_UNLOCK(ipbmap); + return (rc); + } + } + + /* 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; + 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]; + + /* 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 */ + le32_add_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 = NULL, *l0mp = NULL; + 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; + + jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld", + (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 contiguous 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); + if (!l2mp) { + jfs_error(ipbmap->i_sb, "L2 page could not be read\n"); + return -EIO; + } + 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_t(s64, nblocks, 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); + l0mp = NULL; + + 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); + l1mp = NULL; + + 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 */ + + jfs_error(ipbmap->i_sb, "function has not returned as expected\n"); +errout: + if (l0mp) + release_metapage(l0mp); + if (l1mp) + release_metapage(l1mp); + release_metapage(l2mp); + return -EIO; + + /* + * finalize bmap control page + */ +finalize: + + return 0; +} + + +/* + * 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; + } + if (bmp->db_agpref >= bmp->db_numag) { + jfs_error(ipbmap->i_sb, + "cannot find ag with average freespace\n"); + } + } + + /* + * compute db_aglevel, db_agheight, 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_agheight = l2nl >> 1; + bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1)); + for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0; + i--) { + bmp->db_agstart += n; + n <<= 2; + } + +} + + +/* + * 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; + + /* 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 { + le32_add_cpu(&dp->nblocks, nblocks); + le32_add_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) + */ + + 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); + 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] = cpu_to_le32(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); +} |