| /* |
| * 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 |
| */ |
| 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); |
| 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. */ |
| 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(sizeof(struct range2trim) * range_cnt, 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 = 1 << 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); |
| |
|