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linux/fs/jfs/jfs_dmap.c
Dave Kleikamp 3c2c226285 jfs: clean up some compiler warnings 
jfs has a few variables being set but never used.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
2011-07-25 11:01:12 -05:00

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/*
* Copyright (C) International Business Machines Corp., 2000-2004
*
* 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"
/*
* 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);
s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
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;
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,
"dbFree: block to be freed is outside the map");
return -EIO;
}
/*
* 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, "dbFree: 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,
"dbUpdatePMap: blocks are outside the map");
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, "dbAlloc: the hint is outside the map");
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,
"dbExtend: the block is outside the filesystem");
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,
"dbAllocNext: Corrupt dmap page");
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((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,
"dbAllocNear: Corrupt dmap page");
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,
"dbAllocAG: allocation request is larger than the "
"allocation group size");
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,
"dbAllocAG: dbAllocCtl failed in free AG");
}
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,
"dbAllocAG: Corrupt dmapctl page");
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,
"dbAllocAG: failed descending stree");
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,
"dbAllocAG: control page "
"inconsistent");
return -EIO;
}
return (rc);
}
}
/* allocate the blocks.
*/
rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
if (rc == -ENOSPC) {
jfs_error(bmp->db_ipbmap->i_sb,
"dbAllocAG: unable to allocate blocks");
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,
"dbAllocAny: unable to allocate blocks");
return -EIO;
}
return (rc);
}
/*
* NAME: dbFindCtl()
*
* FUNCTION: starting at a specified dmap control page level and block
* number, search down the dmap control levels for a range of
* contiguous free blocks large enough to satisfy an allocation
* request for the specified number of free blocks.
*
* if sufficient contiguous free blocks are found, this routine
* returns the starting block number within a dmap page that
* contains or starts a range of contiqious free blocks that
* is sufficient in size.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* level - starting dmap control page level.
* l2nb - log2 number of contiguous free blocks desired.
* *blkno - on entry, starting block number for conducting the search.
* on successful return, the first block within a dmap page
* that contains or starts a range of contiguous free blocks.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*
* serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
{
int rc, leafidx, lev;
s64 b, lblkno;
struct dmapctl *dcp;
int budmin;
struct metapage *mp;
/* starting at the specified dmap control page level and block
* number, search down the dmap control levels for the starting
* block number of a dmap page that contains or starts off
* sufficient free blocks.
*/
for (lev = level, b = *blkno; lev >= 0; lev--) {
/* get the buffer of the dmap control page for the block
* number and level (i.e. L0, L1, L2).
*/
lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
if (mp == NULL)
return -EIO;
dcp = (struct dmapctl *) mp->data;
budmin = dcp->budmin;
if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
jfs_error(bmp->db_ipbmap->i_sb,
"dbFindCtl: Corrupt dmapctl page");
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,
"dbFindCtl: dmap inconsistent");
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,
"dbAllocCtl: the dmap is not all free");
rc = -EIO;
goto backout;
}
/* determine how many blocks to allocate from this dmap.
*/
nb = min(n, (s64)BPERDMAP);
/* allocate the blocks from the dmap.
*/
if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
release_metapage(mp);
goto backout;
}
/* write the buffer.
*/
write_metapage(mp);
}
/* set the results (starting block number) and return.
*/
*results = blkno;
return (0);
/* something failed in handling an allocation request involving
* multiple dmaps. we'll try to clean up by backing out any
* allocation that has already happened for this request. if
* we fail in backing out the allocation, we'll mark the file
* system to indicate that blocks have been leaked.
*/
backout:
/* try to backout the allocations dmap by dmap.
*/
for (n = nblocks - n, b = blkno; n > 0;
n -= BPERDMAP, b += BPERDMAP) {
/* get the buffer for this dmap.
*/
lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
/* could not back out. mark the file system
* to indicate that we have leaked blocks.
*/
jfs_error(bmp->db_ipbmap->i_sb,
"dbAllocCtl: I/O Error: Block Leakage.");
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,
"dbAllocCtl: Block Leakage.");
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,
"dbAllocBits: leaf page "
"corrupt");
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((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,
"dbAdjCtl: Corrupt dmapctl page");
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,
"dbAdjCtl: the maximum free buddy is "
"not the old root");
}
bmp->db_maxfreebud = dcp->stree[ROOT];
}
}
/* write the buffer.
*/
write_metapage(mp);
return (0);
}
/*
* NAME: dbSplit()
*
* FUNCTION: update the leaf of a dmtree with a new value, splitting
* the leaf from the binary buddy system of the dmtree's
* leaves, as required.
*
* PARAMETERS:
* tp - pointer to the tree containing the leaf.
* leafno - the number of the leaf to be updated.
* splitsz - the size the binary buddy system starting at the leaf
* must be split to, specified as the log2 number of blocks.
* newval - the new value for the leaf.
*
* RETURN VALUES: none
*
* serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
{
int budsz;
int cursz;
s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
/* check if the leaf needs to be split.
*/
if (leaf[leafno] > tp->dmt_budmin) {
/* the split occurs by cutting the buddy system in half
* at the specified leaf until we reach the specified
* size. pick up the starting split size (current size
* - 1 in l2) and the corresponding buddy size.
*/
cursz = leaf[leafno] - 1;
budsz = BUDSIZE(cursz, tp->dmt_budmin);
/* split until we reach the specified size.
*/
while (cursz >= splitsz) {
/* update the buddy's leaf with its new value.
*/
dbAdjTree(tp, leafno ^ budsz, cursz);
/* on to the next size and buddy.
*/
cursz -= 1;
budsz >>= 1;
}
}
/* adjust the dmap tree to reflect the specified leaf's new
* value.
*/
dbAdjTree(tp, leafno, newval);
}
/*
* NAME: dbBackSplit()
*
* FUNCTION: back split the binary buddy system of dmtree leaves
* that hold a specified leaf until the specified leaf
* starts its own binary buddy system.
*
* the allocators typically perform allocations at the start
* of binary buddy systems and dbSplit() is used to accomplish
* any required splits. in some cases, however, allocation
* may occur in the middle of a binary system and requires a
* back split, with the split proceeding out from the middle of
* the system (less efficient) rather than the start of the
* system (more efficient). the cases in which a back split
* is required are rare and are limited to the first allocation
* within an allocation group which is a part (not first part)
* of a larger binary buddy system and a few exception cases
* in which a previous join operation must be backed out.
*
* PARAMETERS:
* tp - pointer to the tree containing the leaf.
* leafno - the number of the leaf to be updated.
*
* RETURN VALUES: none
*
* serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int dbBackSplit(dmtree_t * tp, int leafno)
{
int budsz, bud, w, bsz, size;
int cursz;
s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
/* leaf should be part (not first part) of a binary
* buddy system.
*/
assert(leaf[leafno] == NOFREE);
/* the back split is accomplished by iteratively finding the leaf
* that starts the buddy system that contains the specified leaf and
* splitting that system in two. this iteration continues until
* the specified leaf becomes the start of a buddy system.
*
* determine maximum possible l2 size for the specified leaf.
*/
size =
LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
tp->dmt_budmin);
/* determine the number of leaves covered by this size. this
* is the buddy size that we will start with as we search for
* the buddy system that contains the specified leaf.
*/
budsz = BUDSIZE(size, tp->dmt_budmin);
/* back split.
*/
while (leaf[leafno] == NOFREE) {
/* find the leftmost buddy leaf.
*/
for (w = leafno, bsz = budsz;; bsz <<= 1,
w = (w < bud) ? w : bud) {
if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
jfs_err("JFS: block map error in dbBackSplit");
return -EIO;
}
/* determine the buddy.
*/
bud = w ^ bsz;
/* check if this buddy is the start of the system.
*/
if (leaf[bud] != NOFREE) {
/* split the leaf at the start of the
* system in two.
*/
cursz = leaf[bud] - 1;
dbSplit(tp, bud, cursz, cursz);
break;
}
}
}
if (leaf[leafno] != size) {
jfs_err("JFS: wrong leaf value in dbBackSplit");
return -EIO;
}
return 0;
}
/*
* NAME: dbJoin()
*
* FUNCTION: update the leaf of a dmtree with a new value, joining
* the leaf with other leaves of the dmtree into a multi-leaf
* binary buddy system, as required.
*
* PARAMETERS:
* tp - pointer to the tree containing the leaf.
* leafno - the number of the leaf to be updated.
* newval - the new value for the leaf.
*
* RETURN VALUES: none
*/
static int dbJoin(dmtree_t * tp, int leafno, int newval)
{
int budsz, buddy;
s8 *leaf;
/* can the new leaf value require a join with other leaves ?
*/
if (newval >= tp->dmt_budmin) {
/* pickup a pointer to the leaves of the tree.
*/
leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
/* try to join the specified leaf into a large binary
* buddy system. the join proceeds by attempting to join
* the specified leafno with its buddy (leaf) at new value.
* if the join occurs, we attempt to join the left leaf
* of the joined buddies with its buddy at new value + 1.
* we continue to join until we find a buddy that cannot be
* joined (does not have a value equal to the size of the
* last join) or until all leaves have been joined into a
* single system.
*
* get the buddy size (number of words covered) of
* the new value.
*/
budsz = BUDSIZE(newval, tp->dmt_budmin);
/* try to join.
*/
while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
/* get the buddy leaf.
*/
buddy = leafno ^ budsz;
/* if the leaf's new value is greater than its
* buddy's value, we join no more.
*/
if (newval > leaf[buddy])
break;
/* It shouldn't be less */
if (newval < leaf[buddy])
return -EIO;
/* check which (leafno or buddy) is the left buddy.
* the left buddy gets to claim the blocks resulting
* from the join while the right gets to claim none.
* the left buddy is also eligible to participate in
* a join at the next higher level while the right
* is not.
*
*/
if (leafno < buddy) {
/* leafno is the left buddy.
*/
dbAdjTree(tp, buddy, NOFREE);
} else {
/* buddy is the left buddy and becomes
* leafno.
*/
dbAdjTree(tp, leafno, NOFREE);
leafno = buddy;
}
/* on to try the next join.
*/
newval += 1;
budsz <<= 1;
}
}
/* update the leaf value.
*/
dbAdjTree(tp, leafno, newval);
return 0;
}
/*
* NAME: dbAdjTree()
*
* FUNCTION: update a leaf of a dmtree with a new value, adjusting
* the dmtree, as required, to reflect the new leaf value.
* the combination of any buddies must already be done before
* this is called.
*
* PARAMETERS:
* tp - pointer to the tree to be adjusted.
* leafno - the number of the leaf to be updated.
* newval - the new value for the leaf.
*
* RETURN VALUES: none
*/
static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
{
int lp, pp, k;
int max;
/* pick up the index of the leaf for this leafno.
*/
lp = leafno + le32_to_cpu(tp->dmt_leafidx);
/* is the current value the same as the old value ? if so,
* there is nothing to do.
*/
if (tp->dmt_stree[lp] == newval)
return;
/* set the new value.
*/
tp->dmt_stree[lp] = newval;
/* bubble the new value up the tree as required.
*/
for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
/* get the index of the first leaf of the 4 leaf
* group containing the specified leaf (leafno).
*/
lp = ((lp - 1) & ~0x03) + 1;
/* get the index of the parent of this 4 leaf group.
*/
pp = (lp - 1) >> 2;
/* determine the maximum of the 4 leaves.
*/
max = TREEMAX(&tp->dmt_stree[lp]);
/* if the maximum of the 4 is the same as the
* parent's value, we're done.
*/
if (tp->dmt_stree[pp] == max)
break;
/* parent gets new value.
*/
tp->dmt_stree[pp] = max;
/* parent becomes leaf for next go-round.
*/
lp = pp;
}
}
/*
* NAME: dbFindLeaf()
*
* FUNCTION: search a dmtree_t for sufficient free blocks, returning
* the index of a leaf describing the free blocks if
* sufficient free blocks are found.
*
* the search starts at the top of the dmtree_t tree and
* proceeds down the tree to the leftmost leaf with sufficient
* free space.
*
* PARAMETERS:
* tp - pointer to the tree to be searched.
* l2nb - log2 number of free blocks to search for.
* leafidx - return pointer to be set to the index of the leaf
* describing at least l2nb free blocks if sufficient
* free blocks are found.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient free blocks.
*/
static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
{
int ti, n = 0, k, x = 0;
/* first check the root of the tree to see if there is
* sufficient free space.
*/
if (l2nb > tp->dmt_stree[ROOT])
return -ENOSPC;
/* sufficient free space available. now search down the tree
* starting at the next level for the leftmost leaf that
* describes sufficient free space.
*/
for (k = le32_to_cpu(tp->dmt_height), ti = 1;
k > 0; k--, ti = ((ti + n) << 2) + 1) {
/* search the four nodes at this level, starting from
* the left.
*/
for (x = ti, n = 0; n < 4; n++) {
/* sufficient free space found. move to the next
* level (or quit if this is the last level).
*/
if (l2nb <= tp->dmt_stree[x + n])
break;
}
/* better have found something since the higher
* levels of the tree said it was here.
*/
assert(n < 4);
}
/* set the return to the leftmost leaf describing sufficient
* free space.
*/
*leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
return (0);
}
/*
* NAME: dbFindBits()
*
* FUNCTION: find a specified number of binary buddy free bits within a
* dmap bitmap word value.
*
* this routine searches the bitmap value for (1 << l2nb) free
* bits at (1 << l2nb) alignments within the value.
*
* PARAMETERS:
* word - dmap bitmap word value.
* l2nb - number of free bits specified as a log2 number.
*
* RETURN VALUES:
* starting bit number of free bits.
*/
static int dbFindBits(u32 word, int l2nb)
{
int bitno, nb;
u32 mask;
/* get the number of bits.
*/
nb = 1 << l2nb;
assert(nb <= DBWORD);
/* complement the word so we can use a mask (i.e. 0s represent
* free bits) and compute the mask.
*/
word = ~word;
mask = ONES << (DBWORD - nb);
/* scan the word for nb free bits at nb alignments.
*/
for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
if ((mask & word) == mask)
break;
}
ASSERT(bitno < 32);
/* return the bit number.
*/
return (bitno);
}
/*
* NAME: dbMaxBud(u8 *cp)
*
* FUNCTION: determine the largest binary buddy string of free
* bits within 32-bits of the map.
*
* PARAMETERS:
* cp - pointer to the 32-bit value.
*
* RETURN VALUES:
* largest binary buddy of free bits within a dmap word.
*/
static int dbMaxBud(u8 * cp)
{
signed char tmp1, tmp2;
/* check if the wmap word is all free. if so, the
* free buddy size is BUDMIN.
*/
if (*((uint *) cp) == 0)
return (BUDMIN);
/* check if the wmap word is half free. if so, the
* free buddy size is BUDMIN-1.
*/
if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
return (BUDMIN - 1);
/* not all free or half free. determine the free buddy
* size thru table lookup using quarters of the wmap word.
*/
tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
return (max(tmp1, tmp2));
}
/*
* NAME: cnttz(uint word)
*
* FUNCTION: determine the number of trailing zeros within a 32-bit
* value.
*
* PARAMETERS:
* value - 32-bit value to be examined.
*
* RETURN VALUES:
* count of trailing zeros
*/
static int cnttz(u32 word)
{
int n;
for (n = 0; n < 32; n++, word >>= 1) {
if (word & 0x01)
break;
}
return (n);
}
/*
* NAME: cntlz(u32 value)
*
* FUNCTION: determine the number of leading zeros within a 32-bit
* value.
*
* PARAMETERS:
* value - 32-bit value to be examined.
*
* RETURN VALUES:
* count of leading zeros
*/
static int cntlz(u32 value)
{
int n;
for (n = 0; n < 32; n++, value <<= 1) {
if (value & HIGHORDER)
break;
}
return (n);
}
/*
* NAME: blkstol2(s64 nb)
*
* FUNCTION: convert a block count to its log2 value. if the block
* count is not a l2 multiple, it is rounded up to the next
* larger l2 multiple.
*
* PARAMETERS:
* nb - number of blocks
*
* RETURN VALUES:
* log2 number of blocks
*/
static int blkstol2(s64 nb)
{
int l2nb;
s64 mask; /* meant to be signed */
mask = (s64) 1 << (64 - 1);
/* count the leading bits.
*/
for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
/* leading bit found.
*/
if (nb & mask) {
/* determine the l2 value.
*/
l2nb = (64 - 1) - l2nb;
/* check if we need to round up.
*/
if (~mask & nb)
l2nb++;
return (l2nb);
}
}
assert(0);
return 0; /* fix compiler warning */
}
/*
* NAME: dbAllocBottomUp()
*
* FUNCTION: alloc the specified block range from the working block
* allocation map.
*
* the blocks will be alloc from the working map one dmap
* at a time.
*
* PARAMETERS:
* ip - pointer to in-core inode;
* blkno - starting block number to be freed.
* nblocks - number of blocks to be freed.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*/
int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
{
struct metapage *mp;
struct dmap *dp;
int nb, rc;
s64 lblkno, rem;
struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
/* block to be allocated better be within the mapsize. */
ASSERT(nblocks <= bmp->db_mapsize - blkno);
/*
* allocate the blocks a dmap at a time.
*/
mp = NULL;
for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
/* release previous dmap if any */
if (mp) {
write_metapage(mp);
}
/* get the buffer for the current dmap. */
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
IREAD_UNLOCK(ipbmap);
return -EIO;
}
dp = (struct dmap *) mp->data;
/* determine the number of blocks to be allocated from
* this dmap.
*/
nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
/* allocate the blocks. */
if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
release_metapage(mp);
IREAD_UNLOCK(ipbmap);
return (rc);
}
}
/* write the last buffer. */
write_metapage(mp);
IREAD_UNLOCK(ipbmap);
return (0);
}
static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks)
{
int rc;
int dbitno, word, rembits, nb, nwords, wbitno, agno;
s8 oldroot;
struct dmaptree *tp = (struct dmaptree *) & dp->tree;
/* save the current value of the root (i.e. maximum free string)
* of the dmap tree.
*/
oldroot = tp->stree[ROOT];
/* determine the bit number and word within the dmap of the
* starting block.
*/
dbitno = blkno & (BPERDMAP - 1);
word = dbitno >> L2DBWORD;
/* block range better be within the dmap */
assert(dbitno + nblocks <= BPERDMAP);
/* allocate the bits of the dmap's words corresponding to the block
* range. not all bits of the first and last words may be contained
* within the block range. if this is the case, we'll work against
* those words (i.e. partial first and/or last) on an individual basis
* (a single pass), allocating the bits of interest by hand and
* updating the leaf corresponding to the dmap word. a single pass
* will be used for all dmap words fully contained within the
* specified range. within this pass, the bits of all fully contained
* dmap words will be marked as free in a single shot and the leaves
* will be updated. a single leaf may describe the free space of
* multiple dmap words, so we may update only a subset of the actual
* leaves corresponding to the dmap words of the block range.
*/
for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
/* determine the bit number within the word and
* the number of bits within the word.
*/
wbitno = dbitno & (DBWORD - 1);
nb = min(rembits, DBWORD - wbitno);
/* check if only part of a word is to be allocated.
*/
if (nb < DBWORD) {
/* allocate (set to 1) the appropriate bits within
* this dmap word.
*/
dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
>> wbitno);
word++;
} else {
/* one or more dmap words are fully contained
* within the block range. determine how many
* words and allocate (set to 1) the bits of these
* words.
*/
nwords = rembits >> L2DBWORD;
memset(&dp->wmap[word], (int) ONES, nwords * 4);
/* determine how many bits */
nb = nwords << L2DBWORD;
word += nwords;
}
}
/* update the free count for this dmap */
le32_add_cpu(&dp->nfree, -nblocks);
/* reconstruct summary tree */
dbInitDmapTree(dp);
BMAP_LOCK(bmp);
/* if this allocation group is completely free,
* update the highest active allocation group number
* if this allocation group is the new max.
*/
agno = blkno >> bmp->db_agl2size;
if (agno > bmp->db_maxag)
bmp->db_maxag = agno;
/* update the free count for the allocation group and map */
bmp->db_agfree[agno] -= nblocks;
bmp->db_nfree -= nblocks;
BMAP_UNLOCK(bmp);
/* if the root has not changed, done. */
if (tp->stree[ROOT] == oldroot)
return (0);
/* root changed. bubble the change up to the dmap control pages.
* if the adjustment of the upper level control pages fails,
* backout the bit allocation (thus making everything consistent).
*/
if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
dbFreeBits(bmp, dp, blkno, nblocks);
return (rc);
}
/*
* NAME: dbExtendFS()
*
* FUNCTION: extend bmap from blkno for nblocks;
* dbExtendFS() updates bmap ready for dbAllocBottomUp();
*
* L2
* |
* L1---------------------------------L1
* | |
* L0---------L0---------L0 L0---------L0---------L0
* | | | | | |
* d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm;
* L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
*
* <---old---><----------------------------extend----------------------->
*/
int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
{
struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
int nbperpage = sbi->nbperpage;
int i, i0 = true, j, j0 = true, k, n;
s64 newsize;
s64 p;
struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
struct dmapctl *l2dcp, *l1dcp, *l0dcp;
struct dmap *dp;
s8 *l0leaf, *l1leaf, *l2leaf;
struct bmap *bmp = sbi->bmap;
int agno, l2agsize, oldl2agsize;
s64 ag_rem;
newsize = blkno + nblocks;
jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
(long long) blkno, (long long) nblocks, (long long) newsize);
/*
* initialize bmap control page.
*
* all the data in bmap control page should exclude
* the mkfs hidden dmap page.
*/
/* update mapsize */
bmp->db_mapsize = newsize;
bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
/* compute new AG size */
l2agsize = dbGetL2AGSize(newsize);
oldl2agsize = bmp->db_agl2size;
bmp->db_agl2size = l2agsize;
bmp->db_agsize = 1 << l2agsize;
/* compute new number of AG */
agno = bmp->db_numag;
bmp->db_numag = newsize >> l2agsize;
bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
/*
* reconfigure db_agfree[]
* from old AG configuration to new AG configuration;
*
* coalesce contiguous k (newAGSize/oldAGSize) AGs;
* i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
* note: new AG size = old AG size * (2**x).
*/
if (l2agsize == oldl2agsize)
goto extend;
k = 1 << (l2agsize - oldl2agsize);
ag_rem = bmp->db_agfree[0]; /* save agfree[0] */
for (i = 0, n = 0; i < agno; n++) {
bmp->db_agfree[n] = 0; /* init collection point */
/* coalesce contiguous k AGs; */
for (j = 0; j < k && i < agno; j++, i++) {
/* merge AGi to AGn */
bmp->db_agfree[n] += bmp->db_agfree[i];
}
}
bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */
for (; n < MAXAG; n++)
bmp->db_agfree[n] = 0;
/*
* update highest active ag number
*/
bmp->db_maxag = bmp->db_maxag / k;
/*
* extend bmap
*
* update bit maps and corresponding level control pages;
* global control page db_nfree, db_agfree[agno], db_maxfreebud;
*/
extend:
/* get L2 page */
p = BMAPBLKNO + nbperpage; /* L2 page */
l2mp = read_metapage(ipbmap, p, PSIZE, 0);
if (!l2mp) {
jfs_error(ipbmap->i_sb, "dbExtendFS: L2 page could not be read");
return -EIO;
}
l2dcp = (struct dmapctl *) l2mp->data;
/* compute start L1 */
k = blkno >> L2MAXL1SIZE;
l2leaf = l2dcp->stree + CTLLEAFIND + k;
p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */
/*
* extend each L1 in L2
*/
for (; k < LPERCTL; k++, p += nbperpage) {
/* get L1 page */
if (j0) {
/* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
l1mp = read_metapage(ipbmap, p, PSIZE, 0);
if (l1mp == NULL)
goto errout;
l1dcp = (struct dmapctl *) l1mp->data;
/* compute start L0 */
j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
l1leaf = l1dcp->stree + CTLLEAFIND + j;
p = BLKTOL0(blkno, sbi->l2nbperpage);
j0 = false;
} else {
/* assign/init L1 page */
l1mp = get_metapage(ipbmap, p, PSIZE, 0);
if (l1mp == NULL)
goto errout;
l1dcp = (struct dmapctl *) l1mp->data;
/* compute start L0 */
j = 0;
l1leaf = l1dcp->stree + CTLLEAFIND;
p += nbperpage; /* 1st L0 of L1.k */
}
/*
* extend each L0 in L1
*/
for (; j < LPERCTL; j++) {
/* get L0 page */
if (i0) {
/* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
l0mp = read_metapage(ipbmap, p, PSIZE, 0);
if (l0mp == NULL)
goto errout;
l0dcp = (struct dmapctl *) l0mp->data;
/* compute start dmap */
i = (blkno & (MAXL0SIZE - 1)) >>
L2BPERDMAP;
l0leaf = l0dcp->stree + CTLLEAFIND + i;
p = BLKTODMAP(blkno,
sbi->l2nbperpage);
i0 = false;
} else {
/* assign/init L0 page */
l0mp = get_metapage(ipbmap, p, PSIZE, 0);
if (l0mp == NULL)
goto errout;
l0dcp = (struct dmapctl *) l0mp->data;
/* compute start dmap */
i = 0;
l0leaf = l0dcp->stree + CTLLEAFIND;
p += nbperpage; /* 1st dmap of L0.j */
}
/*
* extend each dmap in L0
*/
for (; i < LPERCTL; i++) {
/*
* reconstruct the dmap page, and
* initialize corresponding parent L0 leaf
*/
if ((n = blkno & (BPERDMAP - 1))) {
/* read in dmap page: */
mp = read_metapage(ipbmap, p,
PSIZE, 0);
if (mp == NULL)
goto errout;
n = min(nblocks, (s64)BPERDMAP - n);
} else {
/* assign/init dmap page */
mp = read_metapage(ipbmap, p,
PSIZE, 0);
if (mp == NULL)
goto errout;
n = min(nblocks, (s64)BPERDMAP);
}
dp = (struct dmap *) mp->data;
*l0leaf = dbInitDmap(dp, blkno, n);
bmp->db_nfree += n;
agno = le64_to_cpu(dp->start) >> l2agsize;
bmp->db_agfree[agno] += n;
write_metapage(mp);
l0leaf++;
p += nbperpage;
blkno += n;
nblocks -= n;
if (nblocks == 0)
break;
} /* for each dmap in a L0 */
/*
* build current L0 page from its leaves, and
* initialize corresponding parent L1 leaf
*/
*l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
write_metapage(l0mp);
l0mp = NULL;
if (nblocks)
l1leaf++; /* continue for next L0 */
else {
/* more than 1 L0 ? */
if (j > 0)
break; /* build L1 page */
else {
/* summarize in global bmap page */
bmp->db_maxfreebud = *l1leaf;
release_metapage(l1mp);
release_metapage(l2mp);
goto finalize;
}
}
} /* for each L0 in a L1 */
/*
* build current L1 page from its leaves, and
* initialize corresponding parent L2 leaf
*/
*l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
write_metapage(l1mp);
l1mp = NULL;
if (nblocks)
l2leaf++; /* continue for next L1 */
else {
/* more than 1 L1 ? */
if (k > 0)
break; /* build L2 page */
else {
/* summarize in global bmap page */
bmp->db_maxfreebud = *l2leaf;
release_metapage(l2mp);
goto finalize;
}
}
} /* for each L1 in a L2 */
jfs_error(ipbmap->i_sb,
"dbExtendFS: function has not returned as expected");
errout:
if (l0mp)
release_metapage(l0mp);
if (l1mp)
release_metapage(l1mp);
release_metapage(l2mp);
return -EIO;
/*
* finalize bmap control page
*/
finalize:
return 0;
}
/*
* dbFinalizeBmap()
*/
void dbFinalizeBmap(struct inode *ipbmap)
{
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
int actags, inactags, l2nl;
s64 ag_rem, actfree, inactfree, avgfree;
int i, n;
/*
* finalize bmap control page
*/
//finalize:
/*
* compute db_agpref: preferred ag to allocate from
* (the leftmost ag with average free space in it);
*/
//agpref:
/* get the number of active ags and inacitve ags */
actags = bmp->db_maxag + 1;
inactags = bmp->db_numag - actags;
ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */
/* determine how many blocks are in the inactive allocation
* groups. in doing this, we must account for the fact that
* the rightmost group might be a partial group (i.e. file
* system size is not a multiple of the group size).
*/
inactfree = (inactags && ag_rem) ?
((inactags - 1) << bmp->db_agl2size) + ag_rem
: inactags << bmp->db_agl2size;
/* determine how many free blocks are in the active
* allocation groups plus the average number of free blocks
* within the active ags.
*/
actfree = bmp->db_nfree - inactfree;
avgfree = (u32) actfree / (u32) actags;
/* if the preferred allocation group has not average free space.
* re-establish the preferred group as the leftmost
* group with average free space.
*/
if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
for (bmp->db_agpref = 0; bmp->db_agpref < actags;
bmp->db_agpref++) {
if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
break;
}
if (bmp->db_agpref >= bmp->db_numag) {
jfs_error(ipbmap->i_sb,
"cannot find ag with average freespace");
}
}
/*
* compute db_aglevel, db_agheight, db_width, db_agstart:
* an ag is covered in aglevel dmapctl summary tree,
* at agheight level height (from leaf) with agwidth number of nodes
* each, which starts at agstart index node of the smmary tree node
* array;
*/
bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
l2nl =
bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
bmp->db_agheight = l2nl >> 1;
bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1));
for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
i--) {
bmp->db_agstart += n;
n <<= 2;
}
}
/*
* NAME: dbInitDmap()/ujfs_idmap_page()
*
* FUNCTION: initialize working/persistent bitmap of the dmap page
* for the specified number of blocks:
*
* at entry, the bitmaps had been initialized as free (ZEROS);
* The number of blocks will only account for the actually
* existing blocks. Blocks which don't actually exist in
* the aggregate will be marked as allocated (ONES);
*
* PARAMETERS:
* dp - pointer to page of map
* nblocks - number of blocks this page
*
* RETURNS: NONE
*/
static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
{
int blkno, w, b, r, nw, nb, i;
/* starting block number within the dmap */
blkno = Blkno & (BPERDMAP - 1);
if (blkno == 0) {
dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
dp->start = cpu_to_le64(Blkno);
if (nblocks == BPERDMAP) {
memset(&dp->wmap[0], 0, LPERDMAP * 4);
memset(&dp->pmap[0], 0, LPERDMAP * 4);
goto initTree;
}
} else {
le32_add_cpu(&dp->nblocks, nblocks);
le32_add_cpu(&dp->nfree, nblocks);
}
/* word number containing start block number */
w = blkno >> L2DBWORD;
/*
* free the bits corresponding to the block range (ZEROS):
* note: not all bits of the first and last words may be contained
* within the block range.
*/
for (r = nblocks; r > 0; r -= nb, blkno += nb) {
/* number of bits preceding range to be freed in the word */
b = blkno & (DBWORD - 1);
/* number of bits to free in the word */
nb = min(r, DBWORD - b);
/* is partial word to be freed ? */
if (nb < DBWORD) {
/* free (set to 0) from the bitmap word */
dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
>> b));
dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
>> b));
/* skip the word freed */
w++;
} else {
/* free (set to 0) contiguous bitmap words */
nw = r >> L2DBWORD;
memset(&dp->wmap[w], 0, nw * 4);
memset(&dp->pmap[w], 0, nw * 4);
/* skip the words freed */
nb = nw << L2DBWORD;
w += nw;
}
}
/*
* mark bits following the range to be freed (non-existing
* blocks) as allocated (ONES)
*/
if (blkno == BPERDMAP)
goto initTree;
/* the first word beyond the end of existing blocks */
w = blkno >> L2DBWORD;
/* does nblocks fall on a 32-bit boundary ? */
b = blkno & (DBWORD - 1);
if (b) {
/* mark a partial word allocated */
dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
w++;
}
/* set the rest of the words in the page to allocated (ONES) */
for (i = w; i < LPERDMAP; i++)
dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
/*
* init tree
*/
initTree:
return (dbInitDmapTree(dp));
}
/*
* NAME: dbInitDmapTree()/ujfs_complete_dmap()
*
* FUNCTION: initialize summary tree of the specified dmap:
*
* at entry, bitmap of the dmap has been initialized;
*
* PARAMETERS:
* dp - dmap to complete
* blkno - starting block number for this dmap
* treemax - will be filled in with max free for this dmap
*
* RETURNS: max free string at the root of the tree
*/
static int dbInitDmapTree(struct dmap * dp)
{
struct dmaptree *tp;
s8 *cp;
int i;
/* init fixed info of tree */
tp = &dp->tree;
tp->nleafs = cpu_to_le32(LPERDMAP);
tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
tp->leafidx = cpu_to_le32(LEAFIND);
tp->height = cpu_to_le32(4);
tp->budmin = BUDMIN;
/* init each leaf from corresponding wmap word:
* note: leaf is set to NOFREE(-1) if all blocks of corresponding
* bitmap word are allocated.
*/
cp = tp->stree + le32_to_cpu(tp->leafidx);
for (i = 0; i < LPERDMAP; i++)
*cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
/* build the dmap's binary buddy summary tree */
return (dbInitTree(tp));
}
/*
* NAME: dbInitTree()/ujfs_adjtree()
*
* FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl.
*
* at entry, the leaves of the tree has been initialized
* from corresponding bitmap word or root of summary tree
* of the child control page;
* configure binary buddy system at the leaf level, then
* bubble up the values of the leaf nodes up the tree.
*
* PARAMETERS:
* cp - Pointer to the root of the tree
* l2leaves- Number of leaf nodes as a power of 2
* l2min - Number of blocks that can be covered by a leaf
* as a power of 2
*
* RETURNS: max free string at the root of the tree
*/
static int dbInitTree(struct dmaptree * dtp)
{
int l2max, l2free, bsize, nextb, i;
int child, parent, nparent;
s8 *tp, *cp, *cp1;
tp = dtp->stree;
/* Determine the maximum free string possible for the leaves */
l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
/*
* configure the leaf levevl into binary buddy system
*
* Try to combine buddies starting with a buddy size of 1
* (i.e. two leaves). At a buddy size of 1 two buddy leaves
* can be combined if both buddies have a maximum free of l2min;
* the combination will result in the left-most buddy leaf having
* a maximum free of l2min+1.
* After processing all buddies for a given size, process buddies
* at the next higher buddy size (i.e. current size * 2) and
* the next maximum free (current free + 1).
* This continues until the maximum possible buddy combination
* yields maximum free.
*/
for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
l2free++, bsize = nextb) {
/* get next buddy size == current buddy pair size */
nextb = bsize << 1;
/* scan each adjacent buddy pair at current buddy size */
for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
i < le32_to_cpu(dtp->nleafs);
i += nextb, cp += nextb) {
/* coalesce if both adjacent buddies are max free */
if (*cp == l2free && *(cp + bsize) == l2free) {
*cp = l2free + 1; /* left take right */
*(cp + bsize) = -1; /* right give left */
}
}
}
/*
* bubble summary information of leaves up the tree.
*
* Starting at the leaf node level, the four nodes described by
* the higher level parent node are compared for a maximum free and
* this maximum becomes the value of the parent node.
* when all lower level nodes are processed in this fashion then
* move up to the next level (parent becomes a lower level node) and
* continue the process for that level.
*/
for (child = le32_to_cpu(dtp->leafidx),
nparent = le32_to_cpu(dtp->nleafs) >> 2;
nparent > 0; nparent >>= 2, child = parent) {
/* get index of 1st node of parent level */
parent = (child - 1) >> 2;
/* set the value of the parent node as the maximum
* of the four nodes of the current level.
*/
for (i = 0, cp = tp + child, cp1 = tp + parent;
i < nparent; i++, cp += 4, cp1++)
*cp1 = TREEMAX(cp);
}
return (*tp);
}
/*
* dbInitDmapCtl()
*
* function: initialize dmapctl page
*/
static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
{ /* start leaf index not covered by range */
s8 *cp;
dcp->nleafs = cpu_to_le32(LPERCTL);
dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
dcp->leafidx = cpu_to_le32(CTLLEAFIND);
dcp->height = cpu_to_le32(5);
dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
/*
* initialize the leaves of current level that were not covered
* by the specified input block range (i.e. the leaves have no
* low level dmapctl or dmap).
*/
cp = &dcp->stree[CTLLEAFIND + i];
for (; i < LPERCTL; i++)
*cp++ = NOFREE;
/* build the dmap's binary buddy summary tree */
return (dbInitTree((struct dmaptree *) dcp));
}
/*
* NAME: dbGetL2AGSize()/ujfs_getagl2size()
*
* FUNCTION: Determine log2(allocation group size) from aggregate size
*
* PARAMETERS:
* nblocks - Number of blocks in aggregate
*
* RETURNS: log2(allocation group size) in aggregate blocks
*/
static int dbGetL2AGSize(s64 nblocks)
{
s64 sz;
s64 m;
int l2sz;
if (nblocks < BPERDMAP * MAXAG)
return (L2BPERDMAP);
/* round up aggregate size to power of 2 */
m = ((u64) 1 << (64 - 1));
for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
if (m & nblocks)
break;
}
sz = (s64) 1 << l2sz;
if (sz < nblocks)
l2sz += 1;
/* agsize = roundupSize/max_number_of_ag */
return (l2sz - L2MAXAG);
}
/*
* NAME: dbMapFileSizeToMapSize()
*
* FUNCTION: compute number of blocks the block allocation map file
* can cover from the map file size;
*
* RETURNS: Number of blocks which can be covered by this block map file;
*/
/*
* maximum number of map pages at each level including control pages
*/
#define MAXL0PAGES (1 + LPERCTL)
#define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES)
#define MAXL2PAGES (1 + LPERCTL * MAXL1PAGES)
/*
* convert number of map pages to the zero origin top dmapctl level
*/
#define BMAPPGTOLEV(npages) \
(((npages) <= 3 + MAXL0PAGES) ? 0 : \
((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
{
struct super_block *sb = ipbmap->i_sb;
s64 nblocks;
s64 npages, ndmaps;
int level, i;
int complete, factor;
nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
level = BMAPPGTOLEV(npages);
/* At each level, accumulate the number of dmap pages covered by
* the number of full child levels below it;
* repeat for the last incomplete child level.
*/
ndmaps = 0;
npages--; /* skip the first global control page */
/* skip higher level control pages above top level covered by map */
npages -= (2 - level);
npages--; /* skip top level's control page */
for (i = level; i >= 0; i--) {
factor =
(i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
complete = (u32) npages / factor;
ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
((i == 1) ? LPERCTL : 1));
/* pages in last/incomplete child */
npages = (u32) npages % factor;
/* skip incomplete child's level control page */
npages--;
}
/* convert the number of dmaps into the number of blocks
* which can be covered by the dmaps;
*/
nblocks = ndmaps << L2BPERDMAP;
return (nblocks);
}
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