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linux/fs/jfs/jfs_dmap.c
Thomas Gleixner 1a59d1b8e0 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:35 -07:00

4080 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) International Business Machines Corp., 2000-2004
* Portions Copyright (C) Tino Reichardt, 2012
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include "jfs_incore.h"
#include "jfs_superblock.h"
#include "jfs_dmap.h"
#include "jfs_imap.h"
#include "jfs_lock.h"
#include "jfs_metapage.h"
#include "jfs_debug.h"
#include "jfs_discard.h"
/*
* SERIALIZATION of the Block Allocation Map.
*
* the working state of the block allocation map is accessed in
* two directions:
*
* 1) allocation and free requests that start at the dmap
* level and move up through the dmap control pages (i.e.
* the vast majority of requests).
*
* 2) allocation requests that start at dmap control page
* level and work down towards the dmaps.
*
* the serialization scheme used here is as follows.
*
* requests which start at the bottom are serialized against each
* other through buffers and each requests holds onto its buffers
* as it works it way up from a single dmap to the required level
* of dmap control page.
* requests that start at the top are serialized against each other
* and request that start from the bottom by the multiple read/single
* write inode lock of the bmap inode. requests starting at the top
* take this lock in write mode while request starting at the bottom
* take the lock in read mode. a single top-down request may proceed
* exclusively while multiple bottoms-up requests may proceed
* simultaneously (under the protection of busy buffers).
*
* in addition to information found in dmaps and dmap control pages,
* the working state of the block allocation map also includes read/
* write information maintained in the bmap descriptor (i.e. total
* free block count, allocation group level free block counts).
* a single exclusive lock (BMAP_LOCK) is used to guard this information
* in the face of multiple-bottoms up requests.
* (lock ordering: IREAD_LOCK, BMAP_LOCK);
*
* accesses to the persistent state of the block allocation map (limited
* to the persistent bitmaps in dmaps) is guarded by (busy) buffers.
*/
#define BMAP_LOCK_INIT(bmp) mutex_init(&bmp->db_bmaplock)
#define BMAP_LOCK(bmp) mutex_lock(&bmp->db_bmaplock)
#define BMAP_UNLOCK(bmp) mutex_unlock(&bmp->db_bmaplock)
/*
* forward references
*/
static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval);
static int dbBackSplit(dmtree_t * tp, int leafno);
static int dbJoin(dmtree_t * tp, int leafno, int newval);
static void dbAdjTree(dmtree_t * tp, int leafno, int newval);
static int dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc,
int level);
static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results);
static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbAllocNear(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks,
int l2nb, s64 * results);
static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbAllocDmapLev(struct bmap * bmp, struct dmap * dp, int nblocks,
int l2nb,
s64 * results);
static int dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb,
s64 * results);
static int dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno,
s64 * results);
static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks);
static int dbFindBits(u32 word, int l2nb);
static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno);
static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx);
static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbMaxBud(u8 * cp);
static int blkstol2(s64 nb);
static int cntlz(u32 value);
static int cnttz(u32 word);
static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks);
static int dbInitDmap(struct dmap * dp, s64 blkno, int nblocks);
static int dbInitDmapTree(struct dmap * dp);
static int dbInitTree(struct dmaptree * dtp);
static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i);
static int dbGetL2AGSize(s64 nblocks);
/*
* buddy table
*
* table used for determining buddy sizes within characters of
* dmap bitmap words. the characters themselves serve as indexes
* into the table, with the table elements yielding the maximum
* binary buddy of free bits within the character.
*/
static const s8 budtab[256] = {
3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
};
/*
* NAME: dbMount()
*
* FUNCTION: initializate the block allocation map.
*
* memory is allocated for the in-core bmap descriptor and
* the in-core descriptor is initialized from disk.
*
* PARAMETERS:
* ipbmap - pointer to in-core inode for the block map.
*
* RETURN VALUES:
* 0 - success
* -ENOMEM - insufficient memory
* -EIO - i/o error
*/
int dbMount(struct inode *ipbmap)
{
struct bmap *bmp;
struct dbmap_disk *dbmp_le;
struct metapage *mp;
int i;
/*
* allocate/initialize the in-memory bmap descriptor
*/
/* allocate memory for the in-memory bmap descriptor */
bmp = kmalloc(sizeof(struct bmap), GFP_KERNEL);
if (bmp == NULL)
return -ENOMEM;
/* read the on-disk bmap descriptor. */
mp = read_metapage(ipbmap,
BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
PSIZE, 0);
if (mp == NULL) {
kfree(bmp);
return -EIO;
}
/* copy the on-disk bmap descriptor to its in-memory version. */
dbmp_le = (struct dbmap_disk *) mp->data;
bmp->db_mapsize = le64_to_cpu(dbmp_le->dn_mapsize);
bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);
bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);
bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag);
bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag);
bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref);
bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel);
bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight);
bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
for (i = 0; i < MAXAG; i++)
bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
bmp->db_maxfreebud = dbmp_le->dn_maxfreebud;
/* release the buffer. */
release_metapage(mp);
/* bind the bmap inode and the bmap descriptor to each other. */
bmp->db_ipbmap = ipbmap;
JFS_SBI(ipbmap->i_sb)->bmap = bmp;
memset(bmp->db_active, 0, sizeof(bmp->db_active));
/*
* allocate/initialize the bmap lock
*/
BMAP_LOCK_INIT(bmp);
return (0);
}
/*
* NAME: dbUnmount()
*
* FUNCTION: terminate the block allocation map in preparation for
* file system unmount.
*
* the in-core bmap descriptor is written to disk and
* the memory for this descriptor is freed.
*
* PARAMETERS:
* ipbmap - pointer to in-core inode for the block map.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*/
int dbUnmount(struct inode *ipbmap, int mounterror)
{
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
if (!(mounterror || isReadOnly(ipbmap)))
dbSync(ipbmap);
/*
* Invalidate the page cache buffers
*/
truncate_inode_pages(ipbmap->i_mapping, 0);
/* free the memory for the in-memory bmap. */
kfree(bmp);
return (0);
}
/*
* dbSync()
*/
int dbSync(struct inode *ipbmap)
{
struct dbmap_disk *dbmp_le;
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
struct metapage *mp;
int i;
/*
* write bmap global control page
*/
/* get the buffer for the on-disk bmap descriptor. */
mp = read_metapage(ipbmap,
BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
PSIZE, 0);
if (mp == NULL) {
jfs_err("dbSync: read_metapage failed!");
return -EIO;
}
/* copy the in-memory version of the bmap to the on-disk version */
dbmp_le = (struct dbmap_disk *) mp->data;
dbmp_le->dn_mapsize = cpu_to_le64(bmp->db_mapsize);
dbmp_le->dn_nfree = cpu_to_le64(bmp->db_nfree);
dbmp_le->dn_l2nbperpage = cpu_to_le32(bmp->db_l2nbperpage);
dbmp_le->dn_numag = cpu_to_le32(bmp->db_numag);
dbmp_le->dn_maxlevel = cpu_to_le32(bmp->db_maxlevel);
dbmp_le->dn_maxag = cpu_to_le32(bmp->db_maxag);
dbmp_le->dn_agpref = cpu_to_le32(bmp->db_agpref);
dbmp_le->dn_aglevel = cpu_to_le32(bmp->db_aglevel);
dbmp_le->dn_agheight = cpu_to_le32(bmp->db_agheight);
dbmp_le->dn_agwidth = cpu_to_le32(bmp->db_agwidth);
dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
dbmp_le->dn_agl2size = cpu_to_le32(bmp->db_agl2size);
for (i = 0; i < MAXAG; i++)
dbmp_le->dn_agfree[i] = cpu_to_le64(bmp->db_agfree[i]);
dbmp_le->dn_agsize = cpu_to_le64(bmp->db_agsize);
dbmp_le->dn_maxfreebud = bmp->db_maxfreebud;
/* write the buffer */
write_metapage(mp);
/*
* write out dirty pages of bmap
*/
filemap_write_and_wait(ipbmap->i_mapping);
diWriteSpecial(ipbmap, 0);
return (0);
}
/*
* NAME: dbFree()
*
* FUNCTION: free the specified block range from the working block
* allocation map.
*
* the blocks will be free from the working map one dmap
* at a time.
*
* PARAMETERS:
* ip - pointer to in-core inode;
* blkno - starting block number to be freed.
* nblocks - number of blocks to be freed.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*/
int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
{
struct metapage *mp;
struct dmap *dp;
int nb, rc;
s64 lblkno, rem;
struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
struct super_block *sb = ipbmap->i_sb;
IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
/* block to be freed better be within the mapsize. */
if (unlikely((blkno == 0) || (blkno + nblocks > bmp->db_mapsize))) {
IREAD_UNLOCK(ipbmap);
printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
(unsigned long long) blkno,
(unsigned long long) nblocks);
jfs_error(ip->i_sb, "block to be freed is outside the map\n");
return -EIO;
}
/**
* TRIM the blocks, when mounted with discard option
*/
if (JFS_SBI(sb)->flag & JFS_DISCARD)
if (JFS_SBI(sb)->minblks_trim <= nblocks)
jfs_issue_discard(ipbmap, blkno, nblocks);
/*
* free the blocks a dmap at a time.
*/
mp = NULL;
for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
/* release previous dmap if any */
if (mp) {
write_metapage(mp);
}
/* get the buffer for the current dmap. */
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
IREAD_UNLOCK(ipbmap);
return -EIO;
}
dp = (struct dmap *) mp->data;
/* determine the number of blocks to be freed from
* this dmap.
*/
nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
/* free the blocks. */
if ((rc = dbFreeDmap(bmp, dp, blkno, nb))) {
jfs_error(ip->i_sb, "error in block map\n");
release_metapage(mp);
IREAD_UNLOCK(ipbmap);
return (rc);
}
}
/* write the last buffer. */
write_metapage(mp);
IREAD_UNLOCK(ipbmap);
return (0);
}
/*
* NAME: dbUpdatePMap()
*
* FUNCTION: update the allocation state (free or allocate) of the
* specified block range in the persistent block allocation map.
*
* the blocks will be updated in the persistent map one
* dmap at a time.
*
* PARAMETERS:
* ipbmap - pointer to in-core inode for the block map.
* free - 'true' if block range is to be freed from the persistent
* map; 'false' if it is to be allocated.
* blkno - starting block number of the range.
* nblocks - number of contiguous blocks in the range.
* tblk - transaction block;
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*/
int
dbUpdatePMap(struct inode *ipbmap,
int free, s64 blkno, s64 nblocks, struct tblock * tblk)
{
int nblks, dbitno, wbitno, rbits;
int word, nbits, nwords;
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
s64 lblkno, rem, lastlblkno;
u32 mask;
struct dmap *dp;
struct metapage *mp;
struct jfs_log *log;
int lsn, difft, diffp;
unsigned long flags;
/* the blocks better be within the mapsize. */
if (blkno + nblocks > bmp->db_mapsize) {
printk(KERN_ERR "blkno = %Lx, nblocks = %Lx\n",
(unsigned long long) blkno,
(unsigned long long) nblocks);
jfs_error(ipbmap->i_sb, "blocks are outside the map\n");
return -EIO;
}
/* compute delta of transaction lsn from log syncpt */
lsn = tblk->lsn;
log = (struct jfs_log *) JFS_SBI(tblk->sb)->log;
logdiff(difft, lsn, log);
/*
* update the block state a dmap at a time.
*/
mp = NULL;
lastlblkno = 0;
for (rem = nblocks; rem > 0; rem -= nblks, blkno += nblks) {
/* get the buffer for the current dmap. */
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
if (lblkno != lastlblkno) {
if (mp) {
write_metapage(mp);
}
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE,
0);
if (mp == NULL)
return -EIO;
metapage_wait_for_io(mp);
}
dp = (struct dmap *) mp->data;
/* determine the bit number and word within the dmap of
* the starting block. also determine how many blocks
* are to be updated within this dmap.
*/
dbitno = blkno & (BPERDMAP - 1);
word = dbitno >> L2DBWORD;
nblks = min(rem, (s64)BPERDMAP - dbitno);
/* update the bits of the dmap words. the first and last
* words may only have a subset of their bits updated. if
* this is the case, we'll work against that word (i.e.
* partial first and/or last) only in a single pass. a
* single pass will also be used to update all words that
* are to have all their bits updated.
*/
for (rbits = nblks; rbits > 0;
rbits -= nbits, dbitno += nbits) {
/* determine the bit number within the word and
* the number of bits within the word.
*/
wbitno = dbitno & (DBWORD - 1);
nbits = min(rbits, DBWORD - wbitno);
/* check if only part of the word is to be updated. */
if (nbits < DBWORD) {
/* update (free or allocate) the bits
* in this word.
*/
mask =
(ONES << (DBWORD - nbits) >> wbitno);
if (free)
dp->pmap[word] &=
cpu_to_le32(~mask);
else
dp->pmap[word] |=
cpu_to_le32(mask);
word += 1;
} else {
/* one or more words are to have all
* their bits updated. determine how
* many words and how many bits.
*/
nwords = rbits >> L2DBWORD;
nbits = nwords << L2DBWORD;
/* update (free or allocate) the bits
* in these words.
*/
if (free)
memset(&dp->pmap[word], 0,
nwords * 4);
else
memset(&dp->pmap[word], (int) ONES,
nwords * 4);
word += nwords;
}
}
/*
* update dmap lsn
*/
if (lblkno == lastlblkno)
continue;
lastlblkno = lblkno;
LOGSYNC_LOCK(log, flags);
if (mp->lsn != 0) {
/* inherit older/smaller lsn */
logdiff(diffp, mp->lsn, log);
if (difft < diffp) {
mp->lsn = lsn;
/* move bp after tblock in logsync list */
list_move(&mp->synclist, &tblk->synclist);
}
/* inherit younger/larger clsn */
logdiff(difft, tblk->clsn, log);
logdiff(diffp, mp->clsn, log);
if (difft > diffp)
mp->clsn = tblk->clsn;
} else {
mp->log = log;
mp->lsn = lsn;
/* insert bp after tblock in logsync list */
log->count++;
list_add(&mp->synclist, &tblk->synclist);
mp->clsn = tblk->clsn;
}
LOGSYNC_UNLOCK(log, flags);
}
/* write the last buffer. */
if (mp) {
write_metapage(mp);
}
return (0);
}
/*
* NAME: dbNextAG()
*
* FUNCTION: find the preferred allocation group for new allocations.
*
* Within the allocation groups, we maintain a preferred
* allocation group which consists of a group with at least
* average free space. It is the preferred group that we target
* new inode allocation towards. The tie-in between inode
* allocation and block allocation occurs as we allocate the
* first (data) block of an inode and specify the inode (block)
* as the allocation hint for this block.
*
* We try to avoid having more than one open file growing in
* an allocation group, as this will lead to fragmentation.
* This differs from the old OS/2 method of trying to keep
* empty ags around for large allocations.
*
* PARAMETERS:
* ipbmap - pointer to in-core inode for the block map.
*
* RETURN VALUES:
* the preferred allocation group number.
*/
int dbNextAG(struct inode *ipbmap)
{
s64 avgfree;
int agpref;
s64 hwm = 0;
int i;
int next_best = -1;
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
BMAP_LOCK(bmp);
/* determine the average number of free blocks within the ags. */
avgfree = (u32)bmp->db_nfree / bmp->db_numag;
/*
* if the current preferred ag does not have an active allocator
* and has at least average freespace, return it
*/
agpref = bmp->db_agpref;
if ((atomic_read(&bmp->db_active[agpref]) == 0) &&
(bmp->db_agfree[agpref] >= avgfree))
goto unlock;
/* From the last preferred ag, find the next one with at least
* average free space.
*/
for (i = 0 ; i < bmp->db_numag; i++, agpref++) {
if (agpref == bmp->db_numag)
agpref = 0;
if (atomic_read(&bmp->db_active[agpref]))
/* open file is currently growing in this ag */
continue;
if (bmp->db_agfree[agpref] >= avgfree) {
/* Return this one */
bmp->db_agpref = agpref;
goto unlock;
} else if (bmp->db_agfree[agpref] > hwm) {
/* Less than avg. freespace, but best so far */
hwm = bmp->db_agfree[agpref];
next_best = agpref;
}
}
/*
* If no inactive ag was found with average freespace, use the
* next best
*/
if (next_best != -1)
bmp->db_agpref = next_best;
/* else leave db_agpref unchanged */
unlock:
BMAP_UNLOCK(bmp);
/* return the preferred group.
*/
return (bmp->db_agpref);
}
/*
* NAME: dbAlloc()
*
* FUNCTION: attempt to allocate a specified number of contiguous free
* blocks from the working allocation block map.
*
* the block allocation policy uses hints and a multi-step
* approach.
*
* for allocation requests smaller than the number of blocks
* per dmap, we first try to allocate the new blocks
* immediately following the hint. if these blocks are not
* available, we try to allocate blocks near the hint. if
* no blocks near the hint are available, we next try to
* allocate within the same dmap as contains the hint.
*
* if no blocks are available in the dmap or the allocation
* request is larger than the dmap size, we try to allocate
* within the same allocation group as contains the hint. if
* this does not succeed, we finally try to allocate anywhere
* within the aggregate.
*
* we also try to allocate anywhere within the aggregate for
* for allocation requests larger than the allocation group
* size or requests that specify no hint value.
*
* PARAMETERS:
* ip - pointer to in-core inode;
* hint - allocation hint.
* nblocks - number of contiguous blocks in the range.
* results - on successful return, set to the starting block number
* of the newly allocated contiguous range.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*/
int dbAlloc(struct inode *ip, s64 hint, s64 nblocks, s64 * results)
{
int rc, agno;
struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
struct bmap *bmp;
struct metapage *mp;
s64 lblkno, blkno;
struct dmap *dp;
int l2nb;
s64 mapSize;
int writers;
/* assert that nblocks is valid */
assert(nblocks > 0);
/* get the log2 number of blocks to be allocated.
* if the number of blocks is not a log2 multiple,
* it will be rounded up to the next log2 multiple.
*/
l2nb = BLKSTOL2(nblocks);
bmp = JFS_SBI(ip->i_sb)->bmap;
mapSize = bmp->db_mapsize;
/* the hint should be within the map */
if (hint >= mapSize) {
jfs_error(ip->i_sb, "the hint is outside the map\n");
return -EIO;
}
/* if the number of blocks to be allocated is greater than the
* allocation group size, try to allocate anywhere.
*/
if (l2nb > bmp->db_agl2size) {
IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
rc = dbAllocAny(bmp, nblocks, l2nb, results);
goto write_unlock;
}
/*
* If no hint, let dbNextAG recommend an allocation group
*/
if (hint == 0)
goto pref_ag;
/* we would like to allocate close to the hint. adjust the
* hint to the block following the hint since the allocators
* will start looking for free space starting at this point.
*/
blkno = hint + 1;
if (blkno >= bmp->db_mapsize)
goto pref_ag;
agno = blkno >> bmp->db_agl2size;
/* check if blkno crosses over into a new allocation group.
* if so, check if we should allow allocations within this
* allocation group.
*/
if ((blkno & (bmp->db_agsize - 1)) == 0)
/* check if the AG is currently being written to.
* if so, call dbNextAG() to find a non-busy
* AG with sufficient free space.
*/
if (atomic_read(&bmp->db_active[agno]))
goto pref_ag;
/* check if the allocation request size can be satisfied from a
* single dmap. if so, try to allocate from the dmap containing
* the hint using a tiered strategy.
*/
if (nblocks <= BPERDMAP) {
IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
/* get the buffer for the dmap containing the hint.
*/
rc = -EIO;
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL)
goto read_unlock;
dp = (struct dmap *) mp->data;
/* first, try to satisfy the allocation request with the
* blocks beginning at the hint.
*/
if ((rc = dbAllocNext(bmp, dp, blkno, (int) nblocks))
!= -ENOSPC) {
if (rc == 0) {
*results = blkno;
mark_metapage_dirty(mp);
}
release_metapage(mp);
goto read_unlock;
}
writers = atomic_read(&bmp->db_active[agno]);
if ((writers > 1) ||
((writers == 1) && (JFS_IP(ip)->active_ag != agno))) {
/*
* Someone else is writing in this allocation
* group. To avoid fragmenting, try another ag
*/
release_metapage(mp);
IREAD_UNLOCK(ipbmap);
goto pref_ag;
}
/* next, try to satisfy the allocation request with blocks
* near the hint.
*/
if ((rc =
dbAllocNear(bmp, dp, blkno, (int) nblocks, l2nb, results))
!= -ENOSPC) {
if (rc == 0)
mark_metapage_dirty(mp);
release_metapage(mp);
goto read_unlock;
}
/* try to satisfy the allocation request with blocks within
* the same dmap as the hint.
*/
if ((rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results))
!= -ENOSPC) {
if (rc == 0)
mark_metapage_dirty(mp);
release_metapage(mp);
goto read_unlock;
}
release_metapage(mp);
IREAD_UNLOCK(ipbmap);
}
/* try to satisfy the allocation request with blocks within
* the same allocation group as the hint.
*/
IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) != -ENOSPC)
goto write_unlock;
IWRITE_UNLOCK(ipbmap);
pref_ag:
/*
* Let dbNextAG recommend a preferred allocation group
*/
agno = dbNextAG(ipbmap);
IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
/* Try to allocate within this allocation group. if that fails, try to
* allocate anywhere in the map.
*/
if ((rc = dbAllocAG(bmp, agno, nblocks, l2nb, results)) == -ENOSPC)
rc = dbAllocAny(bmp, nblocks, l2nb, results);
write_unlock:
IWRITE_UNLOCK(ipbmap);
return (rc);
read_unlock:
IREAD_UNLOCK(ipbmap);
return (rc);
}
#ifdef _NOTYET
/*
* NAME: dbAllocExact()
*
* FUNCTION: try to allocate the requested extent;
*
* PARAMETERS:
* ip - pointer to in-core inode;
* blkno - extent address;
* nblocks - extent length;
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*/
int dbAllocExact(struct inode *ip, s64 blkno, int nblocks)
{
int rc;
struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
struct dmap *dp;
s64 lblkno;
struct metapage *mp;
IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
/*
* validate extent request:
*
* note: defragfs policy:
* max 64 blocks will be moved.
* allocation request size must be satisfied from a single dmap.
*/
if (nblocks <= 0 || nblocks > BPERDMAP || blkno >= bmp->db_mapsize) {
IREAD_UNLOCK(ipbmap);
return -EINVAL;
}
if (nblocks > ((s64) 1 << bmp->db_maxfreebud)) {
/* the free space is no longer available */
IREAD_UNLOCK(ipbmap);
return -ENOSPC;
}
/* read in the dmap covering the extent */
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
IREAD_UNLOCK(ipbmap);
return -EIO;
}
dp = (struct dmap *) mp->data;
/* try to allocate the requested extent */
rc = dbAllocNext(bmp, dp, blkno, nblocks);
IREAD_UNLOCK(ipbmap);
if (rc == 0)
mark_metapage_dirty(mp);
release_metapage(mp);
return (rc);
}
#endif /* _NOTYET */
/*
* NAME: dbReAlloc()
*
* FUNCTION: attempt to extend a current allocation by a specified
* number of blocks.
*
* this routine attempts to satisfy the allocation request
* by first trying to extend the existing allocation in
* place by allocating the additional blocks as the blocks
* immediately following the current allocation. if these
* blocks are not available, this routine will attempt to
* allocate a new set of contiguous blocks large enough
* to cover the existing allocation plus the additional
* number of blocks required.
*
* PARAMETERS:
* ip - pointer to in-core inode requiring allocation.
* blkno - starting block of the current allocation.
* nblocks - number of contiguous blocks within the current
* allocation.
* addnblocks - number of blocks to add to the allocation.
* results - on successful return, set to the starting block number
* of the existing allocation if the existing allocation
* was extended in place or to a newly allocated contiguous
* range if the existing allocation could not be extended
* in place.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*/
int
dbReAlloc(struct inode *ip,
s64 blkno, s64 nblocks, s64 addnblocks, s64 * results)
{
int rc;
/* try to extend the allocation in place.
*/
if ((rc = dbExtend(ip, blkno, nblocks, addnblocks)) == 0) {
*results = blkno;
return (0);
} else {
if (rc != -ENOSPC)
return (rc);
}
/* could not extend the allocation in place, so allocate a
* new set of blocks for the entire request (i.e. try to get
* a range of contiguous blocks large enough to cover the
* existing allocation plus the additional blocks.)
*/
return (dbAlloc
(ip, blkno + nblocks - 1, addnblocks + nblocks, results));
}
/*
* NAME: dbExtend()
*
* FUNCTION: attempt to extend a current allocation by a specified
* number of blocks.
*
* this routine attempts to satisfy the allocation request
* by first trying to extend the existing allocation in
* place by allocating the additional blocks as the blocks
* immediately following the current allocation.
*
* PARAMETERS:
* ip - pointer to in-core inode requiring allocation.
* blkno - starting block of the current allocation.
* nblocks - number of contiguous blocks within the current
* allocation.
* addnblocks - number of blocks to add to the allocation.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*/
static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
{
struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
s64 lblkno, lastblkno, extblkno;
uint rel_block;
struct metapage *mp;
struct dmap *dp;
int rc;
struct inode *ipbmap = sbi->ipbmap;
struct bmap *bmp;
/*
* We don't want a non-aligned extent to cross a page boundary
*/
if (((rel_block = blkno & (sbi->nbperpage - 1))) &&
(rel_block + nblocks + addnblocks > sbi->nbperpage))
return -ENOSPC;
/* get the last block of the current allocation */
lastblkno = blkno + nblocks - 1;
/* determine the block number of the block following
* the existing allocation.
*/
extblkno = lastblkno + 1;
IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
/* better be within the file system */
bmp = sbi->bmap;
if (lastblkno < 0 || lastblkno >= bmp->db_mapsize) {
IREAD_UNLOCK(ipbmap);
jfs_error(ip->i_sb, "the block is outside the filesystem\n");
return -EIO;
}
/* we'll attempt to extend the current allocation in place by
* allocating the additional blocks as the blocks immediately
* following the current allocation. we only try to extend the
* current allocation in place if the number of additional blocks
* can fit into a dmap, the last block of the current allocation
* is not the last block of the file system, and the start of the
* inplace extension is not on an allocation group boundary.
*/
if (addnblocks > BPERDMAP || extblkno >= bmp->db_mapsize ||
(extblkno & (bmp->db_agsize - 1)) == 0) {
IREAD_UNLOCK(ipbmap);
return -ENOSPC;
}
/* get the buffer for the dmap containing the first block
* of the extension.
*/
lblkno = BLKTODMAP(extblkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
IREAD_UNLOCK(ipbmap);
return -EIO;
}
dp = (struct dmap *) mp->data;
/* try to allocate the blocks immediately following the
* current allocation.
*/
rc = dbAllocNext(bmp, dp, extblkno, (int) addnblocks);
IREAD_UNLOCK(ipbmap);
/* were we successful ? */
if (rc == 0)
write_metapage(mp);
else
/* we were not successful */
release_metapage(mp);
return (rc);
}
/*
* NAME: dbAllocNext()
*
* FUNCTION: attempt to allocate the blocks of the specified block
* range within a dmap.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* dp - pointer to dmap.
* blkno - starting block number of the range.
* nblocks - number of contiguous free blocks of the range.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*
* serialization: IREAD_LOCK(ipbmap) held on entry/exit;
*/
static int dbAllocNext(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks)
{
int dbitno, word, rembits, nb, nwords, wbitno, nw;
int l2size;
s8 *leaf;
u32 mask;
if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
return -EIO;
}
/* pick up a pointer to the leaves of the dmap tree.
*/
leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
/* determine the bit number and word within the dmap of the
* starting block.
*/
dbitno = blkno & (BPERDMAP - 1);
word = dbitno >> L2DBWORD;
/* check if the specified block range is contained within
* this dmap.
*/
if (dbitno + nblocks > BPERDMAP)
return -ENOSPC;
/* check if the starting leaf indicates that anything
* is free.
*/
if (leaf[word] == NOFREE)
return -ENOSPC;
/* check the dmaps words corresponding to block range to see
* if the block range is free. not all bits of the first and
* last words may be contained within the block range. if this
* is the case, we'll work against those words (i.e. partial first
* and/or last) on an individual basis (a single pass) and examine
* the actual bits to determine if they are free. a single pass
* will be used for all dmap words fully contained within the
* specified range. within this pass, the leaves of the dmap
* tree will be examined to determine if the blocks are free. a
* single leaf may describe the free space of multiple dmap
* words, so we may visit only a subset of the actual leaves
* corresponding to the dmap words of the block range.
*/
for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
/* determine the bit number within the word and
* the number of bits within the word.
*/
wbitno = dbitno & (DBWORD - 1);
nb = min(rembits, DBWORD - wbitno);
/* check if only part of the word is to be examined.
*/
if (nb < DBWORD) {
/* check if the bits are free.
*/
mask = (ONES << (DBWORD - nb) >> wbitno);
if ((mask & ~le32_to_cpu(dp->wmap[word])) != mask)
return -ENOSPC;
word += 1;
} else {
/* one or more dmap words are fully contained
* within the block range. determine how many
* words and how many bits.
*/
nwords = rembits >> L2DBWORD;
nb = nwords << L2DBWORD;
/* now examine the appropriate leaves to determine
* if the blocks are free.
*/
while (nwords > 0) {
/* does the leaf describe any free space ?
*/
if (leaf[word] < BUDMIN)
return -ENOSPC;
/* determine the l2 number of bits provided
* by this leaf.
*/
l2size =
min_t(int, leaf[word], NLSTOL2BSZ(nwords));
/* determine how many words were handled.
*/
nw = BUDSIZE(l2size, BUDMIN);
nwords -= nw;
word += nw;
}
}
}
/* allocate the blocks.
*/
return (dbAllocDmap(bmp, dp, blkno, nblocks));
}
/*
* NAME: dbAllocNear()
*
* FUNCTION: attempt to allocate a number of contiguous free blocks near
* a specified block (hint) within a dmap.
*
* starting with the dmap leaf that covers the hint, we'll
* check the next four contiguous leaves for sufficient free
* space. if sufficient free space is found, we'll allocate
* the desired free space.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* dp - pointer to dmap.
* blkno - block number to allocate near.
* nblocks - actual number of contiguous free blocks desired.
* l2nb - log2 number of contiguous free blocks desired.
* results - on successful return, set to the starting block number
* of the newly allocated range.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*
* serialization: IREAD_LOCK(ipbmap) held on entry/exit;
*/
static int
dbAllocNear(struct bmap * bmp,
struct dmap * dp, s64 blkno, int nblocks, int l2nb, s64 * results)
{
int word, lword, rc;
s8 *leaf;
if (dp->tree.leafidx != cpu_to_le32(LEAFIND)) {
jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmap page\n");
return -EIO;
}
leaf = dp->tree.stree + le32_to_cpu(dp->tree.leafidx);
/* determine the word within the dmap that holds the hint
* (i.e. blkno). also, determine the last word in the dmap
* that we'll include in our examination.
*/
word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
lword = min(word + 4, LPERDMAP);
/* examine the leaves for sufficient free space.
*/
for (; word < lword; word++) {
/* does the leaf describe sufficient free space ?
*/
if (leaf[word] < l2nb)
continue;
/* determine the block number within the file system
* of the first block described by this dmap word.
*/
blkno = le64_to_cpu(dp->start) + (word << L2DBWORD);
/* if not all bits of the dmap word are free, get the
* starting bit number within the dmap word of the required
* string of free bits and adjust the block number with the
* value.
*/
if (leaf[word] < BUDMIN)
blkno +=
dbFindBits(le32_to_cpu(dp->wmap[word]), l2nb);
/* allocate the blocks.
*/
if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
*results = blkno;
return (rc);
}
return -ENOSPC;
}
/*
* NAME: dbAllocAG()
*
* FUNCTION: attempt to allocate the specified number of contiguous
* free blocks within the specified allocation group.
*
* unless the allocation group size is equal to the number
* of blocks per dmap, the dmap control pages will be used to
* find the required free space, if available. we start the
* search at the highest dmap control page level which
* distinctly describes the allocation group's free space
* (i.e. the highest level at which the allocation group's
* free space is not mixed in with that of any other group).
* in addition, we start the search within this level at a
* height of the dmapctl dmtree at which the nodes distinctly
* describe the allocation group's free space. at this height,
* the allocation group's free space may be represented by 1
* or two sub-trees, depending on the allocation group size.
* we search the top nodes of these subtrees left to right for
* sufficient free space. if sufficient free space is found,
* the subtree is searched to find the leftmost leaf that
* has free space. once we have made it to the leaf, we
* move the search to the next lower level dmap control page
* corresponding to this leaf. we continue down the dmap control
* pages until we find the dmap that contains or starts the
* sufficient free space and we allocate at this dmap.
*
* if the allocation group size is equal to the dmap size,
* we'll start at the dmap corresponding to the allocation
* group and attempt the allocation at this level.
*
* the dmap control page search is also not performed if the
* allocation group is completely free and we go to the first
* dmap of the allocation group to do the allocation. this is
* done because the allocation group may be part (not the first
* part) of a larger binary buddy system, causing the dmap
* control pages to indicate no free space (NOFREE) within
* the allocation group.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* agno - allocation group number.
* nblocks - actual number of contiguous free blocks desired.
* l2nb - log2 number of contiguous free blocks desired.
* results - on successful return, set to the starting block number
* of the newly allocated range.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*
* note: IWRITE_LOCK(ipmap) held on entry/exit;
*/
static int
dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results)
{
struct metapage *mp;
struct dmapctl *dcp;
int rc, ti, i, k, m, n, agperlev;
s64 blkno, lblkno;
int budmin;
/* allocation request should not be for more than the
* allocation group size.
*/
if (l2nb > bmp->db_agl2size) {
jfs_error(bmp->db_ipbmap->i_sb,
"allocation request is larger than the allocation group size\n");
return -EIO;
}
/* determine the starting block number of the allocation
* group.
*/
blkno = (s64) agno << bmp->db_agl2size;
/* check if the allocation group size is the minimum allocation
* group size or if the allocation group is completely free. if
* the allocation group size is the minimum size of BPERDMAP (i.e.
* 1 dmap), there is no need to search the dmap control page (below)
* that fully describes the allocation group since the allocation
* group is already fully described by a dmap. in this case, we
* just call dbAllocCtl() to search the dmap tree and allocate the
* required space if available.
*
* if the allocation group is completely free, dbAllocCtl() is
* also called to allocate the required space. this is done for
* two reasons. first, it makes no sense searching the dmap control
* pages for free space when we know that free space exists. second,
* the dmap control pages may indicate that the allocation group
* has no free space if the allocation group is part (not the first
* part) of a larger binary buddy system.
*/
if (bmp->db_agsize == BPERDMAP
|| bmp->db_agfree[agno] == bmp->db_agsize) {
rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
if ((rc == -ENOSPC) &&
(bmp->db_agfree[agno] == bmp->db_agsize)) {
printk(KERN_ERR "blkno = %Lx, blocks = %Lx\n",
(unsigned long long) blkno,
(unsigned long long) nblocks);
jfs_error(bmp->db_ipbmap->i_sb,
"dbAllocCtl failed in free AG\n");
}
return (rc);
}
/* the buffer for the dmap control page that fully describes the
* allocation group.
*/
lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, bmp->db_aglevel);
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
if (mp == NULL)
return -EIO;
dcp = (struct dmapctl *) mp->data;
budmin = dcp->budmin;
if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
release_metapage(mp);
return -EIO;
}
/* search the subtree(s) of the dmap control page that describes
* the allocation group, looking for sufficient free space. to begin,
* determine how many allocation groups are represented in a dmap
* control page at the control page level (i.e. L0, L1, L2) that
* fully describes an allocation group. next, determine the starting
* tree index of this allocation group within the control page.
*/
agperlev =
(1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth;
ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
/* dmap control page trees fan-out by 4 and a single allocation
* group may be described by 1 or 2 subtrees within the ag level
* dmap control page, depending upon the ag size. examine the ag's
* subtrees for sufficient free space, starting with the leftmost
* subtree.
*/
for (i = 0; i < bmp->db_agwidth; i++, ti++) {
/* is there sufficient free space ?
*/
if (l2nb > dcp->stree[ti])
continue;
/* sufficient free space found in a subtree. now search down
* the subtree to find the leftmost leaf that describes this
* free space.
*/
for (k = bmp->db_agheight; k > 0; k--) {
for (n = 0, m = (ti << 2) + 1; n < 4; n++) {
if (l2nb <= dcp->stree[m + n]) {
ti = m + n;
break;
}
}
if (n == 4) {
jfs_error(bmp->db_ipbmap->i_sb,
"failed descending stree\n");
release_metapage(mp);
return -EIO;
}
}
/* determine the block number within the file system
* that corresponds to this leaf.
*/
if (bmp->db_aglevel == 2)
blkno = 0;
else if (bmp->db_aglevel == 1)
blkno &= ~(MAXL1SIZE - 1);
else /* bmp->db_aglevel == 0 */
blkno &= ~(MAXL0SIZE - 1);
blkno +=
((s64) (ti - le32_to_cpu(dcp->leafidx))) << budmin;
/* release the buffer in preparation for going down
* the next level of dmap control pages.
*/
release_metapage(mp);
/* check if we need to continue to search down the lower
* level dmap control pages. we need to if the number of
* blocks required is less than maximum number of blocks
* described at the next lower level.
*/
if (l2nb < budmin) {
/* search the lower level dmap control pages to get
* the starting block number of the dmap that
* contains or starts off the free space.
*/
if ((rc =
dbFindCtl(bmp, l2nb, bmp->db_aglevel - 1,
&blkno))) {
if (rc == -ENOSPC) {
jfs_error(bmp->db_ipbmap->i_sb,
"control page inconsistent\n");
return -EIO;
}
return (rc);
}
}
/* allocate the blocks.
*/
rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
if (rc == -ENOSPC) {
jfs_error(bmp->db_ipbmap->i_sb,
"unable to allocate blocks\n");
rc = -EIO;
}
return (rc);
}
/* no space in the allocation group. release the buffer and
* return -ENOSPC.
*/
release_metapage(mp);
return -ENOSPC;
}
/*
* NAME: dbAllocAny()
*
* FUNCTION: attempt to allocate the specified number of contiguous
* free blocks anywhere in the file system.
*
* dbAllocAny() attempts to find the sufficient free space by
* searching down the dmap control pages, starting with the
* highest level (i.e. L0, L1, L2) control page. if free space
* large enough to satisfy the desired free space is found, the
* desired free space is allocated.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* nblocks - actual number of contiguous free blocks desired.
* l2nb - log2 number of contiguous free blocks desired.
* results - on successful return, set to the starting block number
* of the newly allocated range.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*
* serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
{
int rc;
s64 blkno = 0;
/* starting with the top level dmap control page, search
* down the dmap control levels for sufficient free space.
* if free space is found, dbFindCtl() returns the starting
* block number of the dmap that contains or starts off the
* range of free space.
*/
if ((rc = dbFindCtl(bmp, l2nb, bmp->db_maxlevel, &blkno)))
return (rc);
/* allocate the blocks.
*/
rc = dbAllocCtl(bmp, nblocks, l2nb, blkno, results);
if (rc == -ENOSPC) {
jfs_error(bmp->db_ipbmap->i_sb, "unable to allocate blocks\n");
return -EIO;
}
return (rc);
}
/*
* NAME: dbDiscardAG()
*
* FUNCTION: attempt to discard (TRIM) all free blocks of specific AG
*
* algorithm:
* 1) allocate blocks, as large as possible and save them
* while holding IWRITE_LOCK on ipbmap
* 2) trim all these saved block/length values
* 3) mark the blocks free again
*
* benefit:
* - we work only on one ag at some time, minimizing how long we
* need to lock ipbmap
* - reading / writing the fs is possible most time, even on
* trimming
*
* downside:
* - we write two times to the dmapctl and dmap pages
* - but for me, this seems the best way, better ideas?
* /TR 2012
*
* PARAMETERS:
* ip - pointer to in-core inode
* agno - ag to trim
* minlen - minimum value of contiguous blocks
*
* RETURN VALUES:
* s64 - actual number of blocks trimmed
*/
s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
{
struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
s64 nblocks, blkno;
u64 trimmed = 0;
int rc, l2nb;
struct super_block *sb = ipbmap->i_sb;
struct range2trim {
u64 blkno;
u64 nblocks;
} *totrim, *tt;
/* max blkno / nblocks pairs to trim */
int count = 0, range_cnt;
u64 max_ranges;
/* prevent others from writing new stuff here, while trimming */
IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
nblocks = bmp->db_agfree[agno];
max_ranges = nblocks;
do_div(max_ranges, minlen);
range_cnt = min_t(u64, max_ranges + 1, 32 * 1024);
totrim = kmalloc_array(range_cnt, sizeof(struct range2trim), GFP_NOFS);
if (totrim == NULL) {
jfs_error(bmp->db_ipbmap->i_sb, "no memory for trim array\n");
IWRITE_UNLOCK(ipbmap);
return 0;
}
tt = totrim;
while (nblocks >= minlen) {
l2nb = BLKSTOL2(nblocks);
/* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */
rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno);
if (rc == 0) {
tt->blkno = blkno;
tt->nblocks = nblocks;
tt++; count++;
/* the whole ag is free, trim now */
if (bmp->db_agfree[agno] == 0)
break;
/* give a hint for the next while */
nblocks = bmp->db_agfree[agno];
continue;
} else if (rc == -ENOSPC) {
/* search for next smaller log2 block */
l2nb = BLKSTOL2(nblocks) - 1;
nblocks = 1 << l2nb;
} else {
/* Trim any already allocated blocks */
jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n");
break;
}
/* check, if our trim array is full */
if (unlikely(count >= range_cnt - 1))
break;
}
IWRITE_UNLOCK(ipbmap);
tt->nblocks = 0; /* mark the current end */
for (tt = totrim; tt->nblocks != 0; tt++) {
/* when mounted with online discard, dbFree() will
* call jfs_issue_discard() itself */
if (!(JFS_SBI(sb)->flag & JFS_DISCARD))
jfs_issue_discard(ip, tt->blkno, tt->nblocks);
dbFree(ip, tt->blkno, tt->nblocks);
trimmed += tt->nblocks;
}
kfree(totrim);
return trimmed;
}
/*
* NAME: dbFindCtl()
*
* FUNCTION: starting at a specified dmap control page level and block
* number, search down the dmap control levels for a range of
* contiguous free blocks large enough to satisfy an allocation
* request for the specified number of free blocks.
*
* if sufficient contiguous free blocks are found, this routine
* returns the starting block number within a dmap page that
* contains or starts a range of contiqious free blocks that
* is sufficient in size.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* level - starting dmap control page level.
* l2nb - log2 number of contiguous free blocks desired.
* *blkno - on entry, starting block number for conducting the search.
* on successful return, the first block within a dmap page
* that contains or starts a range of contiguous free blocks.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*
* serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int dbFindCtl(struct bmap * bmp, int l2nb, int level, s64 * blkno)
{
int rc, leafidx, lev;
s64 b, lblkno;
struct dmapctl *dcp;
int budmin;
struct metapage *mp;
/* starting at the specified dmap control page level and block
* number, search down the dmap control levels for the starting
* block number of a dmap page that contains or starts off
* sufficient free blocks.
*/
for (lev = level, b = *blkno; lev >= 0; lev--) {
/* get the buffer of the dmap control page for the block
* number and level (i.e. L0, L1, L2).
*/
lblkno = BLKTOCTL(b, bmp->db_l2nbperpage, lev);
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
if (mp == NULL)
return -EIO;
dcp = (struct dmapctl *) mp->data;
budmin = dcp->budmin;
if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
jfs_error(bmp->db_ipbmap->i_sb,
"Corrupt dmapctl page\n");
release_metapage(mp);
return -EIO;
}
/* search the tree within the dmap control page for
* sufficient free space. if sufficient free space is found,
* dbFindLeaf() returns the index of the leaf at which
* free space was found.
*/
rc = dbFindLeaf((dmtree_t *) dcp, l2nb, &leafidx);
/* release the buffer.
*/
release_metapage(mp);
/* space found ?
*/
if (rc) {
if (lev != level) {
jfs_error(bmp->db_ipbmap->i_sb,
"dmap inconsistent\n");
return -EIO;
}
return -ENOSPC;
}
/* adjust the block number to reflect the location within
* the dmap control page (i.e. the leaf) at which free
* space was found.
*/
b += (((s64) leafidx) << budmin);
/* we stop the search at this dmap control page level if
* the number of blocks required is greater than or equal
* to the maximum number of blocks described at the next
* (lower) level.
*/
if (l2nb >= budmin)
break;
}
*blkno = b;
return (0);
}
/*
* NAME: dbAllocCtl()
*
* FUNCTION: attempt to allocate a specified number of contiguous
* blocks starting within a specific dmap.
*
* this routine is called by higher level routines that search
* the dmap control pages above the actual dmaps for contiguous
* free space. the result of successful searches by these
* routines are the starting block numbers within dmaps, with
* the dmaps themselves containing the desired contiguous free
* space or starting a contiguous free space of desired size
* that is made up of the blocks of one or more dmaps. these
* calls should not fail due to insufficent resources.
*
* this routine is called in some cases where it is not known
* whether it will fail due to insufficient resources. more
* specifically, this occurs when allocating from an allocation
* group whose size is equal to the number of blocks per dmap.
* in this case, the dmap control pages are not examined prior
* to calling this routine (to save pathlength) and the call
* might fail.
*
* for a request size that fits within a dmap, this routine relies
* upon the dmap's dmtree to find the requested contiguous free
* space. for request sizes that are larger than a dmap, the
* requested free space will start at the first block of the
* first dmap (i.e. blkno).
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* nblocks - actual number of contiguous free blocks to allocate.
* l2nb - log2 number of contiguous free blocks to allocate.
* blkno - starting block number of the dmap to start the allocation
* from.
* results - on successful return, set to the starting block number
* of the newly allocated range.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*
* serialization: IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int
dbAllocCtl(struct bmap * bmp, s64 nblocks, int l2nb, s64 blkno, s64 * results)
{
int rc, nb;
s64 b, lblkno, n;
struct metapage *mp;
struct dmap *dp;
/* check if the allocation request is confined to a single dmap.
*/
if (l2nb <= L2BPERDMAP) {
/* get the buffer for the dmap.
*/
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
if (mp == NULL)
return -EIO;
dp = (struct dmap *) mp->data;
/* try to allocate the blocks.
*/
rc = dbAllocDmapLev(bmp, dp, (int) nblocks, l2nb, results);
if (rc == 0)
mark_metapage_dirty(mp);
release_metapage(mp);
return (rc);
}
/* allocation request involving multiple dmaps. it must start on
* a dmap boundary.
*/
assert((blkno & (BPERDMAP - 1)) == 0);
/* allocate the blocks dmap by dmap.
*/
for (n = nblocks, b = blkno; n > 0; n -= nb, b += nb) {
/* get the buffer for the dmap.
*/
lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
rc = -EIO;
goto backout;
}
dp = (struct dmap *) mp->data;
/* the dmap better be all free.
*/
if (dp->tree.stree[ROOT] != L2BPERDMAP) {
release_metapage(mp);
jfs_error(bmp->db_ipbmap->i_sb,
"the dmap is not all free\n");
rc = -EIO;
goto backout;
}
/* determine how many blocks to allocate from this dmap.
*/
nb = min_t(s64, n, BPERDMAP);
/* allocate the blocks from the dmap.
*/
if ((rc = dbAllocDmap(bmp, dp, b, nb))) {
release_metapage(mp);
goto backout;
}
/* write the buffer.
*/
write_metapage(mp);
}
/* set the results (starting block number) and return.
*/
*results = blkno;
return (0);
/* something failed in handling an allocation request involving
* multiple dmaps. we'll try to clean up by backing out any
* allocation that has already happened for this request. if
* we fail in backing out the allocation, we'll mark the file
* system to indicate that blocks have been leaked.
*/
backout:
/* try to backout the allocations dmap by dmap.
*/
for (n = nblocks - n, b = blkno; n > 0;
n -= BPERDMAP, b += BPERDMAP) {
/* get the buffer for this dmap.
*/
lblkno = BLKTODMAP(b, bmp->db_l2nbperpage);
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
/* could not back out. mark the file system
* to indicate that we have leaked blocks.
*/
jfs_error(bmp->db_ipbmap->i_sb,
"I/O Error: Block Leakage\n");
continue;
}
dp = (struct dmap *) mp->data;
/* free the blocks is this dmap.
*/
if (dbFreeDmap(bmp, dp, b, BPERDMAP)) {
/* could not back out. mark the file system
* to indicate that we have leaked blocks.
*/
release_metapage(mp);
jfs_error(bmp->db_ipbmap->i_sb, "Block Leakage\n");
continue;
}
/* write the buffer.
*/
write_metapage(mp);
}
return (rc);
}
/*
* NAME: dbAllocDmapLev()
*
* FUNCTION: attempt to allocate a specified number of contiguous blocks
* from a specified dmap.
*
* this routine checks if the contiguous blocks are available.
* if so, nblocks of blocks are allocated; otherwise, ENOSPC is
* returned.
*
* PARAMETERS:
* mp - pointer to bmap descriptor
* dp - pointer to dmap to attempt to allocate blocks from.
* l2nb - log2 number of contiguous block desired.
* nblocks - actual number of contiguous block desired.
* results - on successful return, set to the starting block number
* of the newly allocated range.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient disk resources
* -EIO - i/o error
*
* serialization: IREAD_LOCK(ipbmap), e.g., from dbAlloc(), or
* IWRITE_LOCK(ipbmap), e.g., dbAllocCtl(), held on entry/exit;
*/
static int
dbAllocDmapLev(struct bmap * bmp,
struct dmap * dp, int nblocks, int l2nb, s64 * results)
{
s64 blkno;
int leafidx, rc;
/* can't be more than a dmaps worth of blocks */
assert(l2nb <= L2BPERDMAP);
/* search the tree within the dmap page for sufficient
* free space. if sufficient free space is found, dbFindLeaf()
* returns the index of the leaf at which free space was found.
*/
if (dbFindLeaf((dmtree_t *) & dp->tree, l2nb, &leafidx))
return -ENOSPC;
/* determine the block number within the file system corresponding
* to the leaf at which free space was found.
*/
blkno = le64_to_cpu(dp->start) + (leafidx << L2DBWORD);
/* if not all bits of the dmap word are free, get the starting
* bit number within the dmap word of the required string of free
* bits and adjust the block number with this value.
*/
if (dp->tree.stree[leafidx + LEAFIND] < BUDMIN)
blkno += dbFindBits(le32_to_cpu(dp->wmap[leafidx]), l2nb);
/* allocate the blocks */
if ((rc = dbAllocDmap(bmp, dp, blkno, nblocks)) == 0)
*results = blkno;
return (rc);
}
/*
* NAME: dbAllocDmap()
*
* FUNCTION: adjust the disk allocation map to reflect the allocation
* of a specified block range within a dmap.
*
* this routine allocates the specified blocks from the dmap
* through a call to dbAllocBits(). if the allocation of the
* block range causes the maximum string of free blocks within
* the dmap to change (i.e. the value of the root of the dmap's
* dmtree), this routine will cause this change to be reflected
* up through the appropriate levels of the dmap control pages
* by a call to dbAdjCtl() for the L0 dmap control page that
* covers this dmap.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* dp - pointer to dmap to allocate the block range from.
* blkno - starting block number of the block to be allocated.
* nblocks - number of blocks to be allocated.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*
* serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int dbAllocDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks)
{
s8 oldroot;
int rc;
/* save the current value of the root (i.e. maximum free string)
* of the dmap tree.
*/
oldroot = dp->tree.stree[ROOT];
/* allocate the specified (blocks) bits */
dbAllocBits(bmp, dp, blkno, nblocks);
/* if the root has not changed, done. */
if (dp->tree.stree[ROOT] == oldroot)
return (0);
/* root changed. bubble the change up to the dmap control pages.
* if the adjustment of the upper level control pages fails,
* backout the bit allocation (thus making everything consistent).
*/
if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 1, 0)))
dbFreeBits(bmp, dp, blkno, nblocks);
return (rc);
}
/*
* NAME: dbFreeDmap()
*
* FUNCTION: adjust the disk allocation map to reflect the allocation
* of a specified block range within a dmap.
*
* this routine frees the specified blocks from the dmap through
* a call to dbFreeBits(). if the deallocation of the block range
* causes the maximum string of free blocks within the dmap to
* change (i.e. the value of the root of the dmap's dmtree), this
* routine will cause this change to be reflected up through the
* appropriate levels of the dmap control pages by a call to
* dbAdjCtl() for the L0 dmap control page that covers this dmap.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* dp - pointer to dmap to free the block range from.
* blkno - starting block number of the block to be freed.
* nblocks - number of blocks to be freed.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*
* serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks)
{
s8 oldroot;
int rc = 0, word;
/* save the current value of the root (i.e. maximum free string)
* of the dmap tree.
*/
oldroot = dp->tree.stree[ROOT];
/* free the specified (blocks) bits */
rc = dbFreeBits(bmp, dp, blkno, nblocks);
/* if error or the root has not changed, done. */
if (rc || (dp->tree.stree[ROOT] == oldroot))
return (rc);
/* root changed. bubble the change up to the dmap control pages.
* if the adjustment of the upper level control pages fails,
* backout the deallocation.
*/
if ((rc = dbAdjCtl(bmp, blkno, dp->tree.stree[ROOT], 0, 0))) {
word = (blkno & (BPERDMAP - 1)) >> L2DBWORD;
/* as part of backing out the deallocation, we will have
* to back split the dmap tree if the deallocation caused
* the freed blocks to become part of a larger binary buddy
* system.
*/
if (dp->tree.stree[word] == NOFREE)
dbBackSplit((dmtree_t *) & dp->tree, word);
dbAllocBits(bmp, dp, blkno, nblocks);
}
return (rc);
}
/*
* NAME: dbAllocBits()
*
* FUNCTION: allocate a specified block range from a dmap.
*
* this routine updates the dmap to reflect the working
* state allocation of the specified block range. it directly
* updates the bits of the working map and causes the adjustment
* of the binary buddy system described by the dmap's dmtree
* leaves to reflect the bits allocated. it also causes the
* dmap's dmtree, as a whole, to reflect the allocated range.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* dp - pointer to dmap to allocate bits from.
* blkno - starting block number of the bits to be allocated.
* nblocks - number of bits to be allocated.
*
* RETURN VALUES: none
*
* serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static void dbAllocBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks)
{
int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
dmtree_t *tp = (dmtree_t *) & dp->tree;
int size;
s8 *leaf;
/* pick up a pointer to the leaves of the dmap tree */
leaf = dp->tree.stree + LEAFIND;
/* determine the bit number and word within the dmap of the
* starting block.
*/
dbitno = blkno & (BPERDMAP - 1);
word = dbitno >> L2DBWORD;
/* block range better be within the dmap */
assert(dbitno + nblocks <= BPERDMAP);
/* allocate the bits of the dmap's words corresponding to the block
* range. not all bits of the first and last words may be contained
* within the block range. if this is the case, we'll work against
* those words (i.e. partial first and/or last) on an individual basis
* (a single pass), allocating the bits of interest by hand and
* updating the leaf corresponding to the dmap word. a single pass
* will be used for all dmap words fully contained within the
* specified range. within this pass, the bits of all fully contained
* dmap words will be marked as free in a single shot and the leaves
* will be updated. a single leaf may describe the free space of
* multiple dmap words, so we may update only a subset of the actual
* leaves corresponding to the dmap words of the block range.
*/
for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
/* determine the bit number within the word and
* the number of bits within the word.
*/
wbitno = dbitno & (DBWORD - 1);
nb = min(rembits, DBWORD - wbitno);
/* check if only part of a word is to be allocated.
*/
if (nb < DBWORD) {
/* allocate (set to 1) the appropriate bits within
* this dmap word.
*/
dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
>> wbitno);
/* update the leaf for this dmap word. in addition
* to setting the leaf value to the binary buddy max
* of the updated dmap word, dbSplit() will split
* the binary system of the leaves if need be.
*/
dbSplit(tp, word, BUDMIN,
dbMaxBud((u8 *) & dp->wmap[word]));
word += 1;
} else {
/* one or more dmap words are fully contained
* within the block range. determine how many
* words and allocate (set to 1) the bits of these
* words.
*/
nwords = rembits >> L2DBWORD;
memset(&dp->wmap[word], (int) ONES, nwords * 4);
/* determine how many bits.
*/
nb = nwords << L2DBWORD;
/* now update the appropriate leaves to reflect
* the allocated words.
*/
for (; nwords > 0; nwords -= nw) {
if (leaf[word] < BUDMIN) {
jfs_error(bmp->db_ipbmap->i_sb,
"leaf page corrupt\n");
break;
}
/* determine what the leaf value should be
* updated to as the minimum of the l2 number
* of bits being allocated and the l2 number
* of bits currently described by this leaf.
*/
size = min_t(int, leaf[word],
NLSTOL2BSZ(nwords));
/* update the leaf to reflect the allocation.
* in addition to setting the leaf value to
* NOFREE, dbSplit() will split the binary
* system of the leaves to reflect the current
* allocation (size).
*/
dbSplit(tp, word, size, NOFREE);
/* get the number of dmap words handled */
nw = BUDSIZE(size, BUDMIN);
word += nw;
}
}
}
/* update the free count for this dmap */
le32_add_cpu(&dp->nfree, -nblocks);
BMAP_LOCK(bmp);
/* if this allocation group is completely free,
* update the maximum allocation group number if this allocation
* group is the new max.
*/
agno = blkno >> bmp->db_agl2size;
if (agno > bmp->db_maxag)
bmp->db_maxag = agno;
/* update the free count for the allocation group and map */
bmp->db_agfree[agno] -= nblocks;
bmp->db_nfree -= nblocks;
BMAP_UNLOCK(bmp);
}
/*
* NAME: dbFreeBits()
*
* FUNCTION: free a specified block range from a dmap.
*
* this routine updates the dmap to reflect the working
* state allocation of the specified block range. it directly
* updates the bits of the working map and causes the adjustment
* of the binary buddy system described by the dmap's dmtree
* leaves to reflect the bits freed. it also causes the dmap's
* dmtree, as a whole, to reflect the deallocated range.
*
* PARAMETERS:
* bmp - pointer to bmap descriptor
* dp - pointer to dmap to free bits from.
* blkno - starting block number of the bits to be freed.
* nblocks - number of bits to be freed.
*
* RETURN VALUES: 0 for success
*
* serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks)
{
int dbitno, word, rembits, nb, nwords, wbitno, nw, agno;
dmtree_t *tp = (dmtree_t *) & dp->tree;
int rc = 0;
int size;
/* determine the bit number and word within the dmap of the
* starting block.
*/
dbitno = blkno & (BPERDMAP - 1);
word = dbitno >> L2DBWORD;
/* block range better be within the dmap.
*/
assert(dbitno + nblocks <= BPERDMAP);
/* free the bits of the dmaps words corresponding to the block range.
* not all bits of the first and last words may be contained within
* the block range. if this is the case, we'll work against those
* words (i.e. partial first and/or last) on an individual basis
* (a single pass), freeing the bits of interest by hand and updating
* the leaf corresponding to the dmap word. a single pass will be used
* for all dmap words fully contained within the specified range.
* within this pass, the bits of all fully contained dmap words will
* be marked as free in a single shot and the leaves will be updated. a
* single leaf may describe the free space of multiple dmap words,
* so we may update only a subset of the actual leaves corresponding
* to the dmap words of the block range.
*
* dbJoin() is used to update leaf values and will join the binary
* buddy system of the leaves if the new leaf values indicate this
* should be done.
*/
for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
/* determine the bit number within the word and
* the number of bits within the word.
*/
wbitno = dbitno & (DBWORD - 1);
nb = min(rembits, DBWORD - wbitno);
/* check if only part of a word is to be freed.
*/
if (nb < DBWORD) {
/* free (zero) the appropriate bits within this
* dmap word.
*/
dp->wmap[word] &=
cpu_to_le32(~(ONES << (DBWORD - nb)
>> wbitno));
/* update the leaf for this dmap word.
*/
rc = dbJoin(tp, word,
dbMaxBud((u8 *) & dp->wmap[word]));
if (rc)
return rc;
word += 1;
} else {
/* one or more dmap words are fully contained
* within the block range. determine how many
* words and free (zero) the bits of these words.
*/
nwords = rembits >> L2DBWORD;
memset(&dp->wmap[word], 0, nwords * 4);
/* determine how many bits.
*/
nb = nwords << L2DBWORD;
/* now update the appropriate leaves to reflect
* the freed words.
*/
for (; nwords > 0; nwords -= nw) {
/* determine what the leaf value should be
* updated to as the minimum of the l2 number
* of bits being freed and the l2 (max) number
* of bits that can be described by this leaf.
*/
size =
min(LITOL2BSZ
(word, L2LPERDMAP, BUDMIN),
NLSTOL2BSZ(nwords));
/* update the leaf.
*/
rc = dbJoin(tp, word, size);
if (rc)
return rc;
/* get the number of dmap words handled.
*/
nw = BUDSIZE(size, BUDMIN);
word += nw;
}
}
}
/* update the free count for this dmap.
*/
le32_add_cpu(&dp->nfree, nblocks);
BMAP_LOCK(bmp);
/* update the free count for the allocation group and
* map.
*/
agno = blkno >> bmp->db_agl2size;
bmp->db_nfree += nblocks;
bmp->db_agfree[agno] += nblocks;
/* check if this allocation group is not completely free and
* if it is currently the maximum (rightmost) allocation group.
* if so, establish the new maximum allocation group number by
* searching left for the first allocation group with allocation.
*/
if ((bmp->db_agfree[agno] == bmp->db_agsize && agno == bmp->db_maxag) ||
(agno == bmp->db_numag - 1 &&
bmp->db_agfree[agno] == (bmp-> db_mapsize & (BPERDMAP - 1)))) {
while (bmp->db_maxag > 0) {
bmp->db_maxag -= 1;
if (bmp->db_agfree[bmp->db_maxag] !=
bmp->db_agsize)
break;
}
/* re-establish the allocation group preference if the
* current preference is right of the maximum allocation
* group.
*/
if (bmp->db_agpref > bmp->db_maxag)
bmp->db_agpref = bmp->db_maxag;
}
BMAP_UNLOCK(bmp);
return 0;
}
/*
* NAME: dbAdjCtl()
*
* FUNCTION: adjust a dmap control page at a specified level to reflect
* the change in a lower level dmap or dmap control page's
* maximum string of free blocks (i.e. a change in the root
* of the lower level object's dmtree) due to the allocation
* or deallocation of a range of blocks with a single dmap.
*
* on entry, this routine is provided with the new value of
* the lower level dmap or dmap control page root and the
* starting block number of the block range whose allocation
* or deallocation resulted in the root change. this range
* is respresented by a single leaf of the current dmapctl
* and the leaf will be updated with this value, possibly
* causing a binary buddy system within the leaves to be
* split or joined. the update may also cause the dmapctl's
* dmtree to be updated.
*
* if the adjustment of the dmap control page, itself, causes its
* root to change, this change will be bubbled up to the next dmap
* control level by a recursive call to this routine, specifying
* the new root value and the next dmap control page level to
* be adjusted.
* PARAMETERS:
* bmp - pointer to bmap descriptor
* blkno - the first block of a block range within a dmap. it is
* the allocation or deallocation of this block range that
* requires the dmap control page to be adjusted.
* newval - the new value of the lower level dmap or dmap control
* page root.
* alloc - 'true' if adjustment is due to an allocation.
* level - current level of dmap control page (i.e. L0, L1, L2) to
* be adjusted.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*
* serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int
dbAdjCtl(struct bmap * bmp, s64 blkno, int newval, int alloc, int level)
{
struct metapage *mp;
s8 oldroot;
int oldval;
s64 lblkno;
struct dmapctl *dcp;
int rc, leafno, ti;
/* get the buffer for the dmap control page for the specified
* block number and control page level.
*/
lblkno = BLKTOCTL(blkno, bmp->db_l2nbperpage, level);
mp = read_metapage(bmp->db_ipbmap, lblkno, PSIZE, 0);
if (mp == NULL)
return -EIO;
dcp = (struct dmapctl *) mp->data;
if (dcp->leafidx != cpu_to_le32(CTLLEAFIND)) {
jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n");
release_metapage(mp);
return -EIO;
}
/* determine the leaf number corresponding to the block and
* the index within the dmap control tree.
*/
leafno = BLKTOCTLLEAF(blkno, dcp->budmin);
ti = leafno + le32_to_cpu(dcp->leafidx);
/* save the current leaf value and the current root level (i.e.
* maximum l2 free string described by this dmapctl).
*/
oldval = dcp->stree[ti];
oldroot = dcp->stree[ROOT];
/* check if this is a control page update for an allocation.
* if so, update the leaf to reflect the new leaf value using
* dbSplit(); otherwise (deallocation), use dbJoin() to update
* the leaf with the new value. in addition to updating the
* leaf, dbSplit() will also split the binary buddy system of
* the leaves, if required, and bubble new values within the
* dmapctl tree, if required. similarly, dbJoin() will join
* the binary buddy system of leaves and bubble new values up
* the dmapctl tree as required by the new leaf value.
*/
if (alloc) {
/* check if we are in the middle of a binary buddy
* system. this happens when we are performing the
* first allocation out of an allocation group that
* is part (not the first part) of a larger binary
* buddy system. if we are in the middle, back split
* the system prior to calling dbSplit() which assumes
* that it is at the front of a binary buddy system.
*/
if (oldval == NOFREE) {
rc = dbBackSplit((dmtree_t *) dcp, leafno);
if (rc)
return rc;
oldval = dcp->stree[ti];
}
dbSplit((dmtree_t *) dcp, leafno, dcp->budmin, newval);
} else {
rc = dbJoin((dmtree_t *) dcp, leafno, newval);
if (rc)
return rc;
}
/* check if the root of the current dmap control page changed due
* to the update and if the current dmap control page is not at
* the current top level (i.e. L0, L1, L2) of the map. if so (i.e.
* root changed and this is not the top level), call this routine
* again (recursion) for the next higher level of the mapping to
* reflect the change in root for the current dmap control page.
*/
if (dcp->stree[ROOT] != oldroot) {
/* are we below the top level of the map. if so,
* bubble the root up to the next higher level.
*/
if (level < bmp->db_maxlevel) {
/* bubble up the new root of this dmap control page to
* the next level.
*/
if ((rc =
dbAdjCtl(bmp, blkno, dcp->stree[ROOT], alloc,
level + 1))) {
/* something went wrong in bubbling up the new
* root value, so backout the changes to the
* current dmap control page.
*/
if (alloc) {
dbJoin((dmtree_t *) dcp, leafno,
oldval);
} else {
/* the dbJoin() above might have
* caused a larger binary buddy system
* to form and we may now be in the
* middle of it. if this is the case,
* back split the buddies.
*/
if (dcp->stree[ti] == NOFREE)
dbBackSplit((dmtree_t *)
dcp, leafno);
dbSplit((dmtree_t *) dcp, leafno,
dcp->budmin, oldval);
}
/* release the buffer and return the error.
*/
release_metapage(mp);
return (rc);
}
} else {
/* we're at the top level of the map. update
* the bmap control page to reflect the size
* of the maximum free buddy system.
*/
assert(level == bmp->db_maxlevel);
if (bmp->db_maxfreebud != oldroot) {
jfs_error(bmp->db_ipbmap->i_sb,
"the maximum free buddy is not the old root\n");
}
bmp->db_maxfreebud = dcp->stree[ROOT];
}
}
/* write the buffer.
*/
write_metapage(mp);
return (0);
}
/*
* NAME: dbSplit()
*
* FUNCTION: update the leaf of a dmtree with a new value, splitting
* the leaf from the binary buddy system of the dmtree's
* leaves, as required.
*
* PARAMETERS:
* tp - pointer to the tree containing the leaf.
* leafno - the number of the leaf to be updated.
* splitsz - the size the binary buddy system starting at the leaf
* must be split to, specified as the log2 number of blocks.
* newval - the new value for the leaf.
*
* RETURN VALUES: none
*
* serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static void dbSplit(dmtree_t * tp, int leafno, int splitsz, int newval)
{
int budsz;
int cursz;
s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
/* check if the leaf needs to be split.
*/
if (leaf[leafno] > tp->dmt_budmin) {
/* the split occurs by cutting the buddy system in half
* at the specified leaf until we reach the specified
* size. pick up the starting split size (current size
* - 1 in l2) and the corresponding buddy size.
*/
cursz = leaf[leafno] - 1;
budsz = BUDSIZE(cursz, tp->dmt_budmin);
/* split until we reach the specified size.
*/
while (cursz >= splitsz) {
/* update the buddy's leaf with its new value.
*/
dbAdjTree(tp, leafno ^ budsz, cursz);
/* on to the next size and buddy.
*/
cursz -= 1;
budsz >>= 1;
}
}
/* adjust the dmap tree to reflect the specified leaf's new
* value.
*/
dbAdjTree(tp, leafno, newval);
}
/*
* NAME: dbBackSplit()
*
* FUNCTION: back split the binary buddy system of dmtree leaves
* that hold a specified leaf until the specified leaf
* starts its own binary buddy system.
*
* the allocators typically perform allocations at the start
* of binary buddy systems and dbSplit() is used to accomplish
* any required splits. in some cases, however, allocation
* may occur in the middle of a binary system and requires a
* back split, with the split proceeding out from the middle of
* the system (less efficient) rather than the start of the
* system (more efficient). the cases in which a back split
* is required are rare and are limited to the first allocation
* within an allocation group which is a part (not first part)
* of a larger binary buddy system and a few exception cases
* in which a previous join operation must be backed out.
*
* PARAMETERS:
* tp - pointer to the tree containing the leaf.
* leafno - the number of the leaf to be updated.
*
* RETURN VALUES: none
*
* serialization: IREAD_LOCK(ipbmap) or IWRITE_LOCK(ipbmap) held on entry/exit;
*/
static int dbBackSplit(dmtree_t * tp, int leafno)
{
int budsz, bud, w, bsz, size;
int cursz;
s8 *leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
/* leaf should be part (not first part) of a binary
* buddy system.
*/
assert(leaf[leafno] == NOFREE);
/* the back split is accomplished by iteratively finding the leaf
* that starts the buddy system that contains the specified leaf and
* splitting that system in two. this iteration continues until
* the specified leaf becomes the start of a buddy system.
*
* determine maximum possible l2 size for the specified leaf.
*/
size =
LITOL2BSZ(leafno, le32_to_cpu(tp->dmt_l2nleafs),
tp->dmt_budmin);
/* determine the number of leaves covered by this size. this
* is the buddy size that we will start with as we search for
* the buddy system that contains the specified leaf.
*/
budsz = BUDSIZE(size, tp->dmt_budmin);
/* back split.
*/
while (leaf[leafno] == NOFREE) {
/* find the leftmost buddy leaf.
*/
for (w = leafno, bsz = budsz;; bsz <<= 1,
w = (w < bud) ? w : bud) {
if (bsz >= le32_to_cpu(tp->dmt_nleafs)) {
jfs_err("JFS: block map error in dbBackSplit");
return -EIO;
}
/* determine the buddy.
*/
bud = w ^ bsz;
/* check if this buddy is the start of the system.
*/
if (leaf[bud] != NOFREE) {
/* split the leaf at the start of the
* system in two.
*/
cursz = leaf[bud] - 1;
dbSplit(tp, bud, cursz, cursz);
break;
}
}
}
if (leaf[leafno] != size) {
jfs_err("JFS: wrong leaf value in dbBackSplit");
return -EIO;
}
return 0;
}
/*
* NAME: dbJoin()
*
* FUNCTION: update the leaf of a dmtree with a new value, joining
* the leaf with other leaves of the dmtree into a multi-leaf
* binary buddy system, as required.
*
* PARAMETERS:
* tp - pointer to the tree containing the leaf.
* leafno - the number of the leaf to be updated.
* newval - the new value for the leaf.
*
* RETURN VALUES: none
*/
static int dbJoin(dmtree_t * tp, int leafno, int newval)
{
int budsz, buddy;
s8 *leaf;
/* can the new leaf value require a join with other leaves ?
*/
if (newval >= tp->dmt_budmin) {
/* pickup a pointer to the leaves of the tree.
*/
leaf = tp->dmt_stree + le32_to_cpu(tp->dmt_leafidx);
/* try to join the specified leaf into a large binary
* buddy system. the join proceeds by attempting to join
* the specified leafno with its buddy (leaf) at new value.
* if the join occurs, we attempt to join the left leaf
* of the joined buddies with its buddy at new value + 1.
* we continue to join until we find a buddy that cannot be
* joined (does not have a value equal to the size of the
* last join) or until all leaves have been joined into a
* single system.
*
* get the buddy size (number of words covered) of
* the new value.
*/
budsz = BUDSIZE(newval, tp->dmt_budmin);
/* try to join.
*/
while (budsz < le32_to_cpu(tp->dmt_nleafs)) {
/* get the buddy leaf.
*/
buddy = leafno ^ budsz;
/* if the leaf's new value is greater than its
* buddy's value, we join no more.
*/
if (newval > leaf[buddy])
break;
/* It shouldn't be less */
if (newval < leaf[buddy])
return -EIO;
/* check which (leafno or buddy) is the left buddy.
* the left buddy gets to claim the blocks resulting
* from the join while the right gets to claim none.
* the left buddy is also eligible to participate in
* a join at the next higher level while the right
* is not.
*
*/
if (leafno < buddy) {
/* leafno is the left buddy.
*/
dbAdjTree(tp, buddy, NOFREE);
} else {
/* buddy is the left buddy and becomes
* leafno.
*/
dbAdjTree(tp, leafno, NOFREE);
leafno = buddy;
}
/* on to try the next join.
*/
newval += 1;
budsz <<= 1;
}
}
/* update the leaf value.
*/
dbAdjTree(tp, leafno, newval);
return 0;
}
/*
* NAME: dbAdjTree()
*
* FUNCTION: update a leaf of a dmtree with a new value, adjusting
* the dmtree, as required, to reflect the new leaf value.
* the combination of any buddies must already be done before
* this is called.
*
* PARAMETERS:
* tp - pointer to the tree to be adjusted.
* leafno - the number of the leaf to be updated.
* newval - the new value for the leaf.
*
* RETURN VALUES: none
*/
static void dbAdjTree(dmtree_t * tp, int leafno, int newval)
{
int lp, pp, k;
int max;
/* pick up the index of the leaf for this leafno.
*/
lp = leafno + le32_to_cpu(tp->dmt_leafidx);
/* is the current value the same as the old value ? if so,
* there is nothing to do.
*/
if (tp->dmt_stree[lp] == newval)
return;
/* set the new value.
*/
tp->dmt_stree[lp] = newval;
/* bubble the new value up the tree as required.
*/
for (k = 0; k < le32_to_cpu(tp->dmt_height); k++) {
/* get the index of the first leaf of the 4 leaf
* group containing the specified leaf (leafno).
*/
lp = ((lp - 1) & ~0x03) + 1;
/* get the index of the parent of this 4 leaf group.
*/
pp = (lp - 1) >> 2;
/* determine the maximum of the 4 leaves.
*/
max = TREEMAX(&tp->dmt_stree[lp]);
/* if the maximum of the 4 is the same as the
* parent's value, we're done.
*/
if (tp->dmt_stree[pp] == max)
break;
/* parent gets new value.
*/
tp->dmt_stree[pp] = max;
/* parent becomes leaf for next go-round.
*/
lp = pp;
}
}
/*
* NAME: dbFindLeaf()
*
* FUNCTION: search a dmtree_t for sufficient free blocks, returning
* the index of a leaf describing the free blocks if
* sufficient free blocks are found.
*
* the search starts at the top of the dmtree_t tree and
* proceeds down the tree to the leftmost leaf with sufficient
* free space.
*
* PARAMETERS:
* tp - pointer to the tree to be searched.
* l2nb - log2 number of free blocks to search for.
* leafidx - return pointer to be set to the index of the leaf
* describing at least l2nb free blocks if sufficient
* free blocks are found.
*
* RETURN VALUES:
* 0 - success
* -ENOSPC - insufficient free blocks.
*/
static int dbFindLeaf(dmtree_t * tp, int l2nb, int *leafidx)
{
int ti, n = 0, k, x = 0;
/* first check the root of the tree to see if there is
* sufficient free space.
*/
if (l2nb > tp->dmt_stree[ROOT])
return -ENOSPC;
/* sufficient free space available. now search down the tree
* starting at the next level for the leftmost leaf that
* describes sufficient free space.
*/
for (k = le32_to_cpu(tp->dmt_height), ti = 1;
k > 0; k--, ti = ((ti + n) << 2) + 1) {
/* search the four nodes at this level, starting from
* the left.
*/
for (x = ti, n = 0; n < 4; n++) {
/* sufficient free space found. move to the next
* level (or quit if this is the last level).
*/
if (l2nb <= tp->dmt_stree[x + n])
break;
}
/* better have found something since the higher
* levels of the tree said it was here.
*/
assert(n < 4);
}
/* set the return to the leftmost leaf describing sufficient
* free space.
*/
*leafidx = x + n - le32_to_cpu(tp->dmt_leafidx);
return (0);
}
/*
* NAME: dbFindBits()
*
* FUNCTION: find a specified number of binary buddy free bits within a
* dmap bitmap word value.
*
* this routine searches the bitmap value for (1 << l2nb) free
* bits at (1 << l2nb) alignments within the value.
*
* PARAMETERS:
* word - dmap bitmap word value.
* l2nb - number of free bits specified as a log2 number.
*
* RETURN VALUES:
* starting bit number of free bits.
*/
static int dbFindBits(u32 word, int l2nb)
{
int bitno, nb;
u32 mask;
/* get the number of bits.
*/
nb = 1 << l2nb;
assert(nb <= DBWORD);
/* complement the word so we can use a mask (i.e. 0s represent
* free bits) and compute the mask.
*/
word = ~word;
mask = ONES << (DBWORD - nb);
/* scan the word for nb free bits at nb alignments.
*/
for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
if ((mask & word) == mask)
break;
}
ASSERT(bitno < 32);
/* return the bit number.
*/
return (bitno);
}
/*
* NAME: dbMaxBud(u8 *cp)
*
* FUNCTION: determine the largest binary buddy string of free
* bits within 32-bits of the map.
*
* PARAMETERS:
* cp - pointer to the 32-bit value.
*
* RETURN VALUES:
* largest binary buddy of free bits within a dmap word.
*/
static int dbMaxBud(u8 * cp)
{
signed char tmp1, tmp2;
/* check if the wmap word is all free. if so, the
* free buddy size is BUDMIN.
*/
if (*((uint *) cp) == 0)
return (BUDMIN);
/* check if the wmap word is half free. if so, the
* free buddy size is BUDMIN-1.
*/
if (*((u16 *) cp) == 0 || *((u16 *) cp + 1) == 0)
return (BUDMIN - 1);
/* not all free or half free. determine the free buddy
* size thru table lookup using quarters of the wmap word.
*/
tmp1 = max(budtab[cp[2]], budtab[cp[3]]);
tmp2 = max(budtab[cp[0]], budtab[cp[1]]);
return (max(tmp1, tmp2));
}
/*
* NAME: cnttz(uint word)
*
* FUNCTION: determine the number of trailing zeros within a 32-bit
* value.
*
* PARAMETERS:
* value - 32-bit value to be examined.
*
* RETURN VALUES:
* count of trailing zeros
*/
static int cnttz(u32 word)
{
int n;
for (n = 0; n < 32; n++, word >>= 1) {
if (word & 0x01)
break;
}
return (n);
}
/*
* NAME: cntlz(u32 value)
*
* FUNCTION: determine the number of leading zeros within a 32-bit
* value.
*
* PARAMETERS:
* value - 32-bit value to be examined.
*
* RETURN VALUES:
* count of leading zeros
*/
static int cntlz(u32 value)
{
int n;
for (n = 0; n < 32; n++, value <<= 1) {
if (value & HIGHORDER)
break;
}
return (n);
}
/*
* NAME: blkstol2(s64 nb)
*
* FUNCTION: convert a block count to its log2 value. if the block
* count is not a l2 multiple, it is rounded up to the next
* larger l2 multiple.
*
* PARAMETERS:
* nb - number of blocks
*
* RETURN VALUES:
* log2 number of blocks
*/
static int blkstol2(s64 nb)
{
int l2nb;
s64 mask; /* meant to be signed */
mask = (s64) 1 << (64 - 1);
/* count the leading bits.
*/
for (l2nb = 0; l2nb < 64; l2nb++, mask >>= 1) {
/* leading bit found.
*/
if (nb & mask) {
/* determine the l2 value.
*/
l2nb = (64 - 1) - l2nb;
/* check if we need to round up.
*/
if (~mask & nb)
l2nb++;
return (l2nb);
}
}
assert(0);
return 0; /* fix compiler warning */
}
/*
* NAME: dbAllocBottomUp()
*
* FUNCTION: alloc the specified block range from the working block
* allocation map.
*
* the blocks will be alloc from the working map one dmap
* at a time.
*
* PARAMETERS:
* ip - pointer to in-core inode;
* blkno - starting block number to be freed.
* nblocks - number of blocks to be freed.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error
*/
int dbAllocBottomUp(struct inode *ip, s64 blkno, s64 nblocks)
{
struct metapage *mp;
struct dmap *dp;
int nb, rc;
s64 lblkno, rem;
struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
/* block to be allocated better be within the mapsize. */
ASSERT(nblocks <= bmp->db_mapsize - blkno);
/*
* allocate the blocks a dmap at a time.
*/
mp = NULL;
for (rem = nblocks; rem > 0; rem -= nb, blkno += nb) {
/* release previous dmap if any */
if (mp) {
write_metapage(mp);
}
/* get the buffer for the current dmap. */
lblkno = BLKTODMAP(blkno, bmp->db_l2nbperpage);
mp = read_metapage(ipbmap, lblkno, PSIZE, 0);
if (mp == NULL) {
IREAD_UNLOCK(ipbmap);
return -EIO;
}
dp = (struct dmap *) mp->data;
/* determine the number of blocks to be allocated from
* this dmap.
*/
nb = min(rem, BPERDMAP - (blkno & (BPERDMAP - 1)));
/* allocate the blocks. */
if ((rc = dbAllocDmapBU(bmp, dp, blkno, nb))) {
release_metapage(mp);
IREAD_UNLOCK(ipbmap);
return (rc);
}
}
/* write the last buffer. */
write_metapage(mp);
IREAD_UNLOCK(ipbmap);
return (0);
}
static int dbAllocDmapBU(struct bmap * bmp, struct dmap * dp, s64 blkno,
int nblocks)
{
int rc;
int dbitno, word, rembits, nb, nwords, wbitno, agno;
s8 oldroot;
struct dmaptree *tp = (struct dmaptree *) & dp->tree;
/* save the current value of the root (i.e. maximum free string)
* of the dmap tree.
*/
oldroot = tp->stree[ROOT];
/* determine the bit number and word within the dmap of the
* starting block.
*/
dbitno = blkno & (BPERDMAP - 1);
word = dbitno >> L2DBWORD;
/* block range better be within the dmap */
assert(dbitno + nblocks <= BPERDMAP);
/* allocate the bits of the dmap's words corresponding to the block
* range. not all bits of the first and last words may be contained
* within the block range. if this is the case, we'll work against
* those words (i.e. partial first and/or last) on an individual basis
* (a single pass), allocating the bits of interest by hand and
* updating the leaf corresponding to the dmap word. a single pass
* will be used for all dmap words fully contained within the
* specified range. within this pass, the bits of all fully contained
* dmap words will be marked as free in a single shot and the leaves
* will be updated. a single leaf may describe the free space of
* multiple dmap words, so we may update only a subset of the actual
* leaves corresponding to the dmap words of the block range.
*/
for (rembits = nblocks; rembits > 0; rembits -= nb, dbitno += nb) {
/* determine the bit number within the word and
* the number of bits within the word.
*/
wbitno = dbitno & (DBWORD - 1);
nb = min(rembits, DBWORD - wbitno);
/* check if only part of a word is to be allocated.
*/
if (nb < DBWORD) {
/* allocate (set to 1) the appropriate bits within
* this dmap word.
*/
dp->wmap[word] |= cpu_to_le32(ONES << (DBWORD - nb)
>> wbitno);
word++;
} else {
/* one or more dmap words are fully contained
* within the block range. determine how many
* words and allocate (set to 1) the bits of these
* words.
*/
nwords = rembits >> L2DBWORD;
memset(&dp->wmap[word], (int) ONES, nwords * 4);
/* determine how many bits */
nb = nwords << L2DBWORD;
word += nwords;
}
}
/* update the free count for this dmap */
le32_add_cpu(&dp->nfree, -nblocks);
/* reconstruct summary tree */
dbInitDmapTree(dp);
BMAP_LOCK(bmp);
/* if this allocation group is completely free,
* update the highest active allocation group number
* if this allocation group is the new max.
*/
agno = blkno >> bmp->db_agl2size;
if (agno > bmp->db_maxag)
bmp->db_maxag = agno;
/* update the free count for the allocation group and map */
bmp->db_agfree[agno] -= nblocks;
bmp->db_nfree -= nblocks;
BMAP_UNLOCK(bmp);
/* if the root has not changed, done. */
if (tp->stree[ROOT] == oldroot)
return (0);
/* root changed. bubble the change up to the dmap control pages.
* if the adjustment of the upper level control pages fails,
* backout the bit allocation (thus making everything consistent).
*/
if ((rc = dbAdjCtl(bmp, blkno, tp->stree[ROOT], 1, 0)))
dbFreeBits(bmp, dp, blkno, nblocks);
return (rc);
}
/*
* NAME: dbExtendFS()
*
* FUNCTION: extend bmap from blkno for nblocks;
* dbExtendFS() updates bmap ready for dbAllocBottomUp();
*
* L2
* |
* L1---------------------------------L1
* | |
* L0---------L0---------L0 L0---------L0---------L0
* | | | | | |
* d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,...,dn d0,.,dm;
* L2L1L0d0,...,dnL0d0,...,dnL0d0,...,dnL1L0d0,...,dnL0d0,...,dnL0d0,..dm
*
* <---old---><----------------------------extend----------------------->
*/
int dbExtendFS(struct inode *ipbmap, s64 blkno, s64 nblocks)
{
struct jfs_sb_info *sbi = JFS_SBI(ipbmap->i_sb);
int nbperpage = sbi->nbperpage;
int i, i0 = true, j, j0 = true, k, n;
s64 newsize;
s64 p;
struct metapage *mp, *l2mp, *l1mp = NULL, *l0mp = NULL;
struct dmapctl *l2dcp, *l1dcp, *l0dcp;
struct dmap *dp;
s8 *l0leaf, *l1leaf, *l2leaf;
struct bmap *bmp = sbi->bmap;
int agno, l2agsize, oldl2agsize;
s64 ag_rem;
newsize = blkno + nblocks;
jfs_info("dbExtendFS: blkno:%Ld nblocks:%Ld newsize:%Ld",
(long long) blkno, (long long) nblocks, (long long) newsize);
/*
* initialize bmap control page.
*
* all the data in bmap control page should exclude
* the mkfs hidden dmap page.
*/
/* update mapsize */
bmp->db_mapsize = newsize;
bmp->db_maxlevel = BMAPSZTOLEV(bmp->db_mapsize);
/* compute new AG size */
l2agsize = dbGetL2AGSize(newsize);
oldl2agsize = bmp->db_agl2size;
bmp->db_agl2size = l2agsize;
bmp->db_agsize = 1 << l2agsize;
/* compute new number of AG */
agno = bmp->db_numag;
bmp->db_numag = newsize >> l2agsize;
bmp->db_numag += ((u32) newsize % (u32) bmp->db_agsize) ? 1 : 0;
/*
* reconfigure db_agfree[]
* from old AG configuration to new AG configuration;
*
* coalesce contiguous k (newAGSize/oldAGSize) AGs;
* i.e., (AGi, ..., AGj) where i = k*n and j = k*(n+1) - 1 to AGn;
* note: new AG size = old AG size * (2**x).
*/
if (l2agsize == oldl2agsize)
goto extend;
k = 1 << (l2agsize - oldl2agsize);
ag_rem = bmp->db_agfree[0]; /* save agfree[0] */
for (i = 0, n = 0; i < agno; n++) {
bmp->db_agfree[n] = 0; /* init collection point */
/* coalesce contiguous k AGs; */
for (j = 0; j < k && i < agno; j++, i++) {
/* merge AGi to AGn */
bmp->db_agfree[n] += bmp->db_agfree[i];
}
}
bmp->db_agfree[0] += ag_rem; /* restore agfree[0] */
for (; n < MAXAG; n++)
bmp->db_agfree[n] = 0;
/*
* update highest active ag number
*/
bmp->db_maxag = bmp->db_maxag / k;
/*
* extend bmap
*
* update bit maps and corresponding level control pages;
* global control page db_nfree, db_agfree[agno], db_maxfreebud;
*/
extend:
/* get L2 page */
p = BMAPBLKNO + nbperpage; /* L2 page */
l2mp = read_metapage(ipbmap, p, PSIZE, 0);
if (!l2mp) {
jfs_error(ipbmap->i_sb, "L2 page could not be read\n");
return -EIO;
}
l2dcp = (struct dmapctl *) l2mp->data;
/* compute start L1 */
k = blkno >> L2MAXL1SIZE;
l2leaf = l2dcp->stree + CTLLEAFIND + k;
p = BLKTOL1(blkno, sbi->l2nbperpage); /* L1 page */
/*
* extend each L1 in L2
*/
for (; k < LPERCTL; k++, p += nbperpage) {
/* get L1 page */
if (j0) {
/* read in L1 page: (blkno & (MAXL1SIZE - 1)) */
l1mp = read_metapage(ipbmap, p, PSIZE, 0);
if (l1mp == NULL)
goto errout;
l1dcp = (struct dmapctl *) l1mp->data;
/* compute start L0 */
j = (blkno & (MAXL1SIZE - 1)) >> L2MAXL0SIZE;
l1leaf = l1dcp->stree + CTLLEAFIND + j;
p = BLKTOL0(blkno, sbi->l2nbperpage);
j0 = false;
} else {
/* assign/init L1 page */
l1mp = get_metapage(ipbmap, p, PSIZE, 0);
if (l1mp == NULL)
goto errout;
l1dcp = (struct dmapctl *) l1mp->data;
/* compute start L0 */
j = 0;
l1leaf = l1dcp->stree + CTLLEAFIND;
p += nbperpage; /* 1st L0 of L1.k */
}
/*
* extend each L0 in L1
*/
for (; j < LPERCTL; j++) {
/* get L0 page */
if (i0) {
/* read in L0 page: (blkno & (MAXL0SIZE - 1)) */
l0mp = read_metapage(ipbmap, p, PSIZE, 0);
if (l0mp == NULL)
goto errout;
l0dcp = (struct dmapctl *) l0mp->data;
/* compute start dmap */
i = (blkno & (MAXL0SIZE - 1)) >>
L2BPERDMAP;
l0leaf = l0dcp->stree + CTLLEAFIND + i;
p = BLKTODMAP(blkno,
sbi->l2nbperpage);
i0 = false;
} else {
/* assign/init L0 page */
l0mp = get_metapage(ipbmap, p, PSIZE, 0);
if (l0mp == NULL)
goto errout;
l0dcp = (struct dmapctl *) l0mp->data;
/* compute start dmap */
i = 0;
l0leaf = l0dcp->stree + CTLLEAFIND;
p += nbperpage; /* 1st dmap of L0.j */
}
/*
* extend each dmap in L0
*/
for (; i < LPERCTL; i++) {
/*
* reconstruct the dmap page, and
* initialize corresponding parent L0 leaf
*/
if ((n = blkno & (BPERDMAP - 1))) {
/* read in dmap page: */
mp = read_metapage(ipbmap, p,
PSIZE, 0);
if (mp == NULL)
goto errout;
n = min(nblocks, (s64)BPERDMAP - n);
} else {
/* assign/init dmap page */
mp = read_metapage(ipbmap, p,
PSIZE, 0);
if (mp == NULL)
goto errout;
n = min_t(s64, nblocks, BPERDMAP);
}
dp = (struct dmap *) mp->data;
*l0leaf = dbInitDmap(dp, blkno, n);
bmp->db_nfree += n;
agno = le64_to_cpu(dp->start) >> l2agsize;
bmp->db_agfree[agno] += n;
write_metapage(mp);
l0leaf++;
p += nbperpage;
blkno += n;
nblocks -= n;
if (nblocks == 0)
break;
} /* for each dmap in a L0 */
/*
* build current L0 page from its leaves, and
* initialize corresponding parent L1 leaf
*/
*l1leaf = dbInitDmapCtl(l0dcp, 0, ++i);
write_metapage(l0mp);
l0mp = NULL;
if (nblocks)
l1leaf++; /* continue for next L0 */
else {
/* more than 1 L0 ? */
if (j > 0)
break; /* build L1 page */
else {
/* summarize in global bmap page */
bmp->db_maxfreebud = *l1leaf;
release_metapage(l1mp);
release_metapage(l2mp);
goto finalize;
}
}
} /* for each L0 in a L1 */
/*
* build current L1 page from its leaves, and
* initialize corresponding parent L2 leaf
*/
*l2leaf = dbInitDmapCtl(l1dcp, 1, ++j);
write_metapage(l1mp);
l1mp = NULL;
if (nblocks)
l2leaf++; /* continue for next L1 */
else {
/* more than 1 L1 ? */
if (k > 0)
break; /* build L2 page */
else {
/* summarize in global bmap page */
bmp->db_maxfreebud = *l2leaf;
release_metapage(l2mp);
goto finalize;
}
}
} /* for each L1 in a L2 */
jfs_error(ipbmap->i_sb, "function has not returned as expected\n");
errout:
if (l0mp)
release_metapage(l0mp);
if (l1mp)
release_metapage(l1mp);
release_metapage(l2mp);
return -EIO;
/*
* finalize bmap control page
*/
finalize:
return 0;
}
/*
* dbFinalizeBmap()
*/
void dbFinalizeBmap(struct inode *ipbmap)
{
struct bmap *bmp = JFS_SBI(ipbmap->i_sb)->bmap;
int actags, inactags, l2nl;
s64 ag_rem, actfree, inactfree, avgfree;
int i, n;
/*
* finalize bmap control page
*/
//finalize:
/*
* compute db_agpref: preferred ag to allocate from
* (the leftmost ag with average free space in it);
*/
//agpref:
/* get the number of active ags and inacitve ags */
actags = bmp->db_maxag + 1;
inactags = bmp->db_numag - actags;
ag_rem = bmp->db_mapsize & (bmp->db_agsize - 1); /* ??? */
/* determine how many blocks are in the inactive allocation
* groups. in doing this, we must account for the fact that
* the rightmost group might be a partial group (i.e. file
* system size is not a multiple of the group size).
*/
inactfree = (inactags && ag_rem) ?
((inactags - 1) << bmp->db_agl2size) + ag_rem
: inactags << bmp->db_agl2size;
/* determine how many free blocks are in the active
* allocation groups plus the average number of free blocks
* within the active ags.
*/
actfree = bmp->db_nfree - inactfree;
avgfree = (u32) actfree / (u32) actags;
/* if the preferred allocation group has not average free space.
* re-establish the preferred group as the leftmost
* group with average free space.
*/
if (bmp->db_agfree[bmp->db_agpref] < avgfree) {
for (bmp->db_agpref = 0; bmp->db_agpref < actags;
bmp->db_agpref++) {
if (bmp->db_agfree[bmp->db_agpref] >= avgfree)
break;
}
if (bmp->db_agpref >= bmp->db_numag) {
jfs_error(ipbmap->i_sb,
"cannot find ag with average freespace\n");
}
}
/*
* compute db_aglevel, db_agheight, db_width, db_agstart:
* an ag is covered in aglevel dmapctl summary tree,
* at agheight level height (from leaf) with agwidth number of nodes
* each, which starts at agstart index node of the smmary tree node
* array;
*/
bmp->db_aglevel = BMAPSZTOLEV(bmp->db_agsize);
l2nl =
bmp->db_agl2size - (L2BPERDMAP + bmp->db_aglevel * L2LPERCTL);
bmp->db_agheight = l2nl >> 1;
bmp->db_agwidth = 1 << (l2nl - (bmp->db_agheight << 1));
for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
i--) {
bmp->db_agstart += n;
n <<= 2;
}
}
/*
* NAME: dbInitDmap()/ujfs_idmap_page()
*
* FUNCTION: initialize working/persistent bitmap of the dmap page
* for the specified number of blocks:
*
* at entry, the bitmaps had been initialized as free (ZEROS);
* The number of blocks will only account for the actually
* existing blocks. Blocks which don't actually exist in
* the aggregate will be marked as allocated (ONES);
*
* PARAMETERS:
* dp - pointer to page of map
* nblocks - number of blocks this page
*
* RETURNS: NONE
*/
static int dbInitDmap(struct dmap * dp, s64 Blkno, int nblocks)
{
int blkno, w, b, r, nw, nb, i;
/* starting block number within the dmap */
blkno = Blkno & (BPERDMAP - 1);
if (blkno == 0) {
dp->nblocks = dp->nfree = cpu_to_le32(nblocks);
dp->start = cpu_to_le64(Blkno);
if (nblocks == BPERDMAP) {
memset(&dp->wmap[0], 0, LPERDMAP * 4);
memset(&dp->pmap[0], 0, LPERDMAP * 4);
goto initTree;
}
} else {
le32_add_cpu(&dp->nblocks, nblocks);
le32_add_cpu(&dp->nfree, nblocks);
}
/* word number containing start block number */
w = blkno >> L2DBWORD;
/*
* free the bits corresponding to the block range (ZEROS):
* note: not all bits of the first and last words may be contained
* within the block range.
*/
for (r = nblocks; r > 0; r -= nb, blkno += nb) {
/* number of bits preceding range to be freed in the word */
b = blkno & (DBWORD - 1);
/* number of bits to free in the word */
nb = min(r, DBWORD - b);
/* is partial word to be freed ? */
if (nb < DBWORD) {
/* free (set to 0) from the bitmap word */
dp->wmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
>> b));
dp->pmap[w] &= cpu_to_le32(~(ONES << (DBWORD - nb)
>> b));
/* skip the word freed */
w++;
} else {
/* free (set to 0) contiguous bitmap words */
nw = r >> L2DBWORD;
memset(&dp->wmap[w], 0, nw * 4);
memset(&dp->pmap[w], 0, nw * 4);
/* skip the words freed */
nb = nw << L2DBWORD;
w += nw;
}
}
/*
* mark bits following the range to be freed (non-existing
* blocks) as allocated (ONES)
*/
if (blkno == BPERDMAP)
goto initTree;
/* the first word beyond the end of existing blocks */
w = blkno >> L2DBWORD;
/* does nblocks fall on a 32-bit boundary ? */
b = blkno & (DBWORD - 1);
if (b) {
/* mark a partial word allocated */
dp->wmap[w] = dp->pmap[w] = cpu_to_le32(ONES >> b);
w++;
}
/* set the rest of the words in the page to allocated (ONES) */
for (i = w; i < LPERDMAP; i++)
dp->pmap[i] = dp->wmap[i] = cpu_to_le32(ONES);
/*
* init tree
*/
initTree:
return (dbInitDmapTree(dp));
}
/*
* NAME: dbInitDmapTree()/ujfs_complete_dmap()
*
* FUNCTION: initialize summary tree of the specified dmap:
*
* at entry, bitmap of the dmap has been initialized;
*
* PARAMETERS:
* dp - dmap to complete
* blkno - starting block number for this dmap
* treemax - will be filled in with max free for this dmap
*
* RETURNS: max free string at the root of the tree
*/
static int dbInitDmapTree(struct dmap * dp)
{
struct dmaptree *tp;
s8 *cp;
int i;
/* init fixed info of tree */
tp = &dp->tree;
tp->nleafs = cpu_to_le32(LPERDMAP);
tp->l2nleafs = cpu_to_le32(L2LPERDMAP);
tp->leafidx = cpu_to_le32(LEAFIND);
tp->height = cpu_to_le32(4);
tp->budmin = BUDMIN;
/* init each leaf from corresponding wmap word:
* note: leaf is set to NOFREE(-1) if all blocks of corresponding
* bitmap word are allocated.
*/
cp = tp->stree + le32_to_cpu(tp->leafidx);
for (i = 0; i < LPERDMAP; i++)
*cp++ = dbMaxBud((u8 *) & dp->wmap[i]);
/* build the dmap's binary buddy summary tree */
return (dbInitTree(tp));
}
/*
* NAME: dbInitTree()/ujfs_adjtree()
*
* FUNCTION: initialize binary buddy summary tree of a dmap or dmapctl.
*
* at entry, the leaves of the tree has been initialized
* from corresponding bitmap word or root of summary tree
* of the child control page;
* configure binary buddy system at the leaf level, then
* bubble up the values of the leaf nodes up the tree.
*
* PARAMETERS:
* cp - Pointer to the root of the tree
* l2leaves- Number of leaf nodes as a power of 2
* l2min - Number of blocks that can be covered by a leaf
* as a power of 2
*
* RETURNS: max free string at the root of the tree
*/
static int dbInitTree(struct dmaptree * dtp)
{
int l2max, l2free, bsize, nextb, i;
int child, parent, nparent;
s8 *tp, *cp, *cp1;
tp = dtp->stree;
/* Determine the maximum free string possible for the leaves */
l2max = le32_to_cpu(dtp->l2nleafs) + dtp->budmin;
/*
* configure the leaf levevl into binary buddy system
*
* Try to combine buddies starting with a buddy size of 1
* (i.e. two leaves). At a buddy size of 1 two buddy leaves
* can be combined if both buddies have a maximum free of l2min;
* the combination will result in the left-most buddy leaf having
* a maximum free of l2min+1.
* After processing all buddies for a given size, process buddies
* at the next higher buddy size (i.e. current size * 2) and
* the next maximum free (current free + 1).
* This continues until the maximum possible buddy combination
* yields maximum free.
*/
for (l2free = dtp->budmin, bsize = 1; l2free < l2max;
l2free++, bsize = nextb) {
/* get next buddy size == current buddy pair size */
nextb = bsize << 1;
/* scan each adjacent buddy pair at current buddy size */
for (i = 0, cp = tp + le32_to_cpu(dtp->leafidx);
i < le32_to_cpu(dtp->nleafs);
i += nextb, cp += nextb) {
/* coalesce if both adjacent buddies are max free */
if (*cp == l2free && *(cp + bsize) == l2free) {
*cp = l2free + 1; /* left take right */
*(cp + bsize) = -1; /* right give left */
}
}
}
/*
* bubble summary information of leaves up the tree.
*
* Starting at the leaf node level, the four nodes described by
* the higher level parent node are compared for a maximum free and
* this maximum becomes the value of the parent node.
* when all lower level nodes are processed in this fashion then
* move up to the next level (parent becomes a lower level node) and
* continue the process for that level.
*/
for (child = le32_to_cpu(dtp->leafidx),
nparent = le32_to_cpu(dtp->nleafs) >> 2;
nparent > 0; nparent >>= 2, child = parent) {
/* get index of 1st node of parent level */
parent = (child - 1) >> 2;
/* set the value of the parent node as the maximum
* of the four nodes of the current level.
*/
for (i = 0, cp = tp + child, cp1 = tp + parent;
i < nparent; i++, cp += 4, cp1++)
*cp1 = TREEMAX(cp);
}
return (*tp);
}
/*
* dbInitDmapCtl()
*
* function: initialize dmapctl page
*/
static int dbInitDmapCtl(struct dmapctl * dcp, int level, int i)
{ /* start leaf index not covered by range */
s8 *cp;
dcp->nleafs = cpu_to_le32(LPERCTL);
dcp->l2nleafs = cpu_to_le32(L2LPERCTL);
dcp->leafidx = cpu_to_le32(CTLLEAFIND);
dcp->height = cpu_to_le32(5);
dcp->budmin = L2BPERDMAP + L2LPERCTL * level;
/*
* initialize the leaves of current level that were not covered
* by the specified input block range (i.e. the leaves have no
* low level dmapctl or dmap).
*/
cp = &dcp->stree[CTLLEAFIND + i];
for (; i < LPERCTL; i++)
*cp++ = NOFREE;
/* build the dmap's binary buddy summary tree */
return (dbInitTree((struct dmaptree *) dcp));
}
/*
* NAME: dbGetL2AGSize()/ujfs_getagl2size()
*
* FUNCTION: Determine log2(allocation group size) from aggregate size
*
* PARAMETERS:
* nblocks - Number of blocks in aggregate
*
* RETURNS: log2(allocation group size) in aggregate blocks
*/
static int dbGetL2AGSize(s64 nblocks)
{
s64 sz;
s64 m;
int l2sz;
if (nblocks < BPERDMAP * MAXAG)
return (L2BPERDMAP);
/* round up aggregate size to power of 2 */
m = ((u64) 1 << (64 - 1));
for (l2sz = 64; l2sz >= 0; l2sz--, m >>= 1) {
if (m & nblocks)
break;
}
sz = (s64) 1 << l2sz;
if (sz < nblocks)
l2sz += 1;
/* agsize = roundupSize/max_number_of_ag */
return (l2sz - L2MAXAG);
}
/*
* NAME: dbMapFileSizeToMapSize()
*
* FUNCTION: compute number of blocks the block allocation map file
* can cover from the map file size;
*
* RETURNS: Number of blocks which can be covered by this block map file;
*/
/*
* maximum number of map pages at each level including control pages
*/
#define MAXL0PAGES (1 + LPERCTL)
#define MAXL1PAGES (1 + LPERCTL * MAXL0PAGES)
#define MAXL2PAGES (1 + LPERCTL * MAXL1PAGES)
/*
* convert number of map pages to the zero origin top dmapctl level
*/
#define BMAPPGTOLEV(npages) \
(((npages) <= 3 + MAXL0PAGES) ? 0 : \
((npages) <= 2 + MAXL1PAGES) ? 1 : 2)
s64 dbMapFileSizeToMapSize(struct inode * ipbmap)
{
struct super_block *sb = ipbmap->i_sb;
s64 nblocks;
s64 npages, ndmaps;
int level, i;
int complete, factor;
nblocks = ipbmap->i_size >> JFS_SBI(sb)->l2bsize;
npages = nblocks >> JFS_SBI(sb)->l2nbperpage;
level = BMAPPGTOLEV(npages);
/* At each level, accumulate the number of dmap pages covered by
* the number of full child levels below it;
* repeat for the last incomplete child level.
*/
ndmaps = 0;
npages--; /* skip the first global control page */
/* skip higher level control pages above top level covered by map */
npages -= (2 - level);
npages--; /* skip top level's control page */
for (i = level; i >= 0; i--) {
factor =
(i == 2) ? MAXL1PAGES : ((i == 1) ? MAXL0PAGES : 1);
complete = (u32) npages / factor;
ndmaps += complete * ((i == 2) ? LPERCTL * LPERCTL :
((i == 1) ? LPERCTL : 1));
/* pages in last/incomplete child */
npages = (u32) npages % factor;
/* skip incomplete child's level control page */
npages--;
}
/* convert the number of dmaps into the number of blocks
* which can be covered by the dmaps;
*/
nblocks = ndmaps << L2BPERDMAP;
return (nblocks);
}
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