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jfs_dmap.c
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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 "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) init_MUTEX(&bmp->db_bmaplock)
#define BMAP_LOCK(bmp) down(&bmp->db_bmaplock)
#define BMAP_UNLOCK(bmp) up(&bmp->db_bmaplock)
/*
* forward references
*/
static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
static 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 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_agheigth = le32_to_cpu(dbmp_le->dn_agheigth);
bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
for (i = 0; i < MAXAG; i++)
bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
/* release the buffer. */
release_metapage(mp);
/* bind the bmap inode and the bmap descriptor to each other. */
bmp->db_ipbmap = ipbmap;
JFS_SBI(ipbmap->i_sb)->bmap = bmp;
memset(bmp->db_active, 0, sizeof(bmp->db_active));
/*
* 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_agheigth = cpu_to_le32(bmp->db_agheigth);
dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
for (i = 0; i < MAXAG; i++)
dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
/* write the buffer */
write_metapage(mp);
/*
* write out dirty pages of bmap
*/
filemap_fdatawrite(ipbmap->i_mapping);
filemap_fdatawait(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);
/* 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;
if (mp->lsn != 0) {
/* inherit older/smaller lsn */
logdiff(diffp, mp->lsn, log);
LOGSYNC_LOCK(log, flags);
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;
LOGSYNC_UNLOCK(log, flags);
} else {
mp->log = log;
mp->lsn = lsn;
/* insert bp after tblock in logsync list */
LOGSYNC_LOCK(log, flags);
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);
#ifdef _STILL_TO_PORT
/* DASD limit check F226941 */
if (OVER_LIMIT(ip, nblocks))
return -ENOSPC;
#endif /* _STILL_TO_PORT */
/* get the log2 number of blocks to be allocated.
* if the number of blocks is not a log2 multiple,
* it will be rounded up to the next log2 multiple.
*/
l2nb = BLKSTOL2(nblocks);
bmp = JFS_SBI(ip->i_sb)->bmap;
//retry: /* serialize w.r.t.extendfs() */
mapSize = bmp->db_mapsize;
/* the hint should be within the map */
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);
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 currenly being written to.
* if so, call dbNextAG() to find a non-busy
* AG with sufficient free space.
*/
if (atomic_read(&bmp->db_active[agno]))
goto pref_ag;
/* check if the allocation request size can be satisfied from a
* single dmap. if so, try to allocate from the dmap containing
* the hint using a tiered strategy.
*/
if (nblocks <= BPERDMAP) {
IREAD_LOCK(ipbmap);
/* get the buffer for the dmap containing the hint.
*/
rc = -EIO;
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL)
goto read_unlock;
dp = (struct dmap *) mp->data;
/* first, try to satisfy the allocation request with the
* blocks beginning at the hint.
*/
if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
!= -ENOSPC) {
if (rc == 0) {
*results = blkno;
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);
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);
/* 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);
/*
* 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