- 根目录:
- fs
- jfs
- jfs_extent.c
/*
* Copyright (C) International Business Machines Corp., 2000-2004
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/quotaops.h>
#include "jfs_incore.h"
#include "jfs_inode.h"
#include "jfs_superblock.h"
#include "jfs_dmap.h"
#include "jfs_extent.h"
#include "jfs_debug.h"
/*
* forward references
*/
static int extBalloc(struct inode *, s64, s64 *, s64 *);
#ifdef _NOTYET
static int extBrealloc(struct inode *, s64, s64, s64 *, s64 *);
#endif
static s64 extRoundDown(s64 nb);
#define DPD(a) (printk("(a): %d\n",(a)))
#define DPC(a) (printk("(a): %c\n",(a)))
#define DPL1(a) \
{ \
if ((a) >> 32) \
printk("(a): %x%08x ",(a)); \
else \
printk("(a): %x ",(a) << 32); \
}
#define DPL(a) \
{ \
if ((a) >> 32) \
printk("(a): %x%08x\n",(a)); \
else \
printk("(a): %x\n",(a) << 32); \
}
#define DPD1(a) (printk("(a): %d ",(a)))
#define DPX(a) (printk("(a): %08x\n",(a)))
#define DPX1(a) (printk("(a): %08x ",(a)))
#define DPS(a) (printk("%s\n",(a)))
#define DPE(a) (printk("\nENTERING: %s\n",(a)))
#define DPE1(a) (printk("\nENTERING: %s",(a)))
#define DPS1(a) (printk(" %s ",(a)))
/*
* NAME: extAlloc()
*
* FUNCTION: allocate an extent for a specified page range within a
* file.
*
* PARAMETERS:
* ip - the inode of the file.
* xlen - requested extent length.
* pno - the starting page number with the file.
* xp - pointer to an xad. on entry, xad describes an
* extent that is used as an allocation hint if the
* xaddr of the xad is non-zero. on successful exit,
* the xad describes the newly allocated extent.
* abnr - bool indicating whether the newly allocated extent
* should be marked as allocated but not recorded.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error.
* -ENOSPC - insufficient disk resources.
*/
int
extAlloc(struct inode *ip, s64 xlen, s64 pno, xad_t * xp, bool abnr)
{
struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
s64 nxlen, nxaddr, xoff, hint, xaddr = 0;
int rc;
int xflag;
/* This blocks if we are low on resources */
txBeginAnon(ip->i_sb);
/* Avoid race with jfs_commit_inode() */
mutex_lock(&JFS_IP(ip)->commit_mutex);
/* validate extent length */
if (xlen > MAXXLEN)
xlen = MAXXLEN;
/* get the page's starting extent offset */
xoff = pno << sbi->l2nbperpage;
/* check if an allocation hint was provided */
if ((hint = addressXAD(xp))) {
/* get the size of the extent described by the hint */
nxlen = lengthXAD(xp);
/* check if the hint is for the portion of the file
* immediately previous to the current allocation
* request and if hint extent has the same abnr
* value as the current request. if so, we can
* extend the hint extent to include the current
* extent if we can allocate the blocks immediately
* following the hint extent.
*/
if (offsetXAD(xp) + nxlen == xoff &&
abnr == ((xp->flag & XAD_NOTRECORDED) ? true : false))
xaddr = hint + nxlen;
/* adjust the hint to the last block of the extent */
hint += (nxlen - 1);
}
/* allocate the disk blocks for the extent. initially, extBalloc()
* will try to allocate disk blocks for the requested size (xlen).
* if this fails (xlen contiguous free blocks not available), it'll
* try to allocate a smaller number of blocks (producing a smaller
* extent), with this smaller number of blocks consisting of the
* requested number of blocks rounded down to the next smaller
* power of 2 number (i.e. 16 -> 8). it'll continue to round down
* and retry the allocation until the number of blocks to allocate
* is smaller than the number of blocks per page.
*/
nxlen = xlen;
if ((rc = extBalloc(ip, hint ? hint : INOHINT(ip), &nxlen, &nxaddr))) {
mutex_unlock(&JFS_IP(ip)->commit_mutex);
return (rc);
}
/* Allocate blocks to quota. */
rc = dquot_alloc_block(ip, nxlen);
if (rc) {
dbFree(ip, nxaddr, (s64) nxlen);
mutex_unlock(&JFS_IP(ip)->commit_mutex);
return rc;
}
/* determine the value of the extent flag */
xflag = abnr ? XAD_NOTRECORDED : 0;
/* if we can extend the hint extent to cover the current request,
* extend it. otherwise, insert a new extent to
* cover the current request.
*/
if (xaddr && xaddr == nxaddr)
rc = xtExtend(0, ip, xoff, (int) nxlen, 0);
else
rc = xtInsert(0, ip, xflag, xoff, (int) nxlen, &nxaddr, 0);
/* if the extend or insert failed,
* free the newly allocated blocks and return the error.
*/
if (rc) {
dbFree(ip, nxaddr, nxlen);
dquot_free_block(ip, nxlen);
mutex_unlock(&JFS_IP(ip)->commit_mutex);
return (rc);
}
/* set the results of the extent allocation */
XADaddress(xp, nxaddr);
XADlength(xp, nxlen);
XADoffset(xp, xoff);
xp->flag = xflag;
mark_inode_dirty(ip);
mutex_unlock(&JFS_IP(ip)->commit_mutex);
/*
* COMMIT_SyncList flags an anonymous tlock on page that is on
* sync list.
* We need to commit the inode to get the page written disk.
*/
if (test_and_clear_cflag(COMMIT_Synclist,ip))
jfs_commit_inode(ip, 0);
return (0);
}
#ifdef _NOTYET
/*
* NAME: extRealloc()
*
* FUNCTION: extend the allocation of a file extent containing a
* partial back last page.
*
* PARAMETERS:
* ip - the inode of the file.
* cp - cbuf for the partial backed last page.
* xlen - request size of the resulting extent.
* xp - pointer to an xad. on successful exit, the xad
* describes the newly allocated extent.
* abnr - bool indicating whether the newly allocated extent
* should be marked as allocated but not recorded.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error.
* -ENOSPC - insufficient disk resources.
*/
int extRealloc(struct inode *ip, s64 nxlen, xad_t * xp, bool abnr)
{
struct super_block *sb = ip->i_sb;
s64 xaddr, xlen, nxaddr, delta, xoff;
s64 ntail, nextend, ninsert;
int rc, nbperpage = JFS_SBI(sb)->nbperpage;
int xflag;
/* This blocks if we are low on resources */
txBeginAnon(ip->i_sb);
mutex_lock(&JFS_IP(ip)->commit_mutex);
/* validate extent length */
if (nxlen > MAXXLEN)
nxlen = MAXXLEN;
/* get the extend (partial) page's disk block address and
* number of blocks.
*/
xaddr = addressXAD(xp);
xlen = lengthXAD(xp);
xoff = offsetXAD(xp);
/* if the extend page is abnr and if the request is for
* the extent to be allocated and recorded,
* make the page allocated and recorded.
*/
if ((xp->flag & XAD_NOTRECORDED) && !abnr) {
xp->flag = 0;
if ((rc = xtUpdate(0, ip, xp)))
goto exit;
}
/* try to allocated the request number of blocks for the
* extent. dbRealloc() first tries to satisfy the request
* by extending the allocation in place. otherwise, it will
* try to allocate a new set of blocks large enough for the
* request. in satisfying a request, dbReAlloc() may allocate
* less than what was request but will always allocate enough
* space as to satisfy the extend page.
*/
if ((rc = extBrealloc(ip, xaddr, xlen, &nxlen, &nxaddr)))
goto exit;
/* Allocat blocks to quota. */
rc = dquot_alloc_block(ip, nxlen);
if (rc) {
dbFree(ip, nxaddr, (s64) nxlen);
mutex_unlock(&JFS_IP(ip)->commit_mutex);
return rc;
}
delta = nxlen - xlen;
/* check if the extend page is not abnr but the request is abnr
* and the allocated disk space is for more than one page. if this
* is the case, there is a miss match of abnr between the extend page
* and the one or more pages following the extend page. as a result,
* two extents will have to be manipulated. the first will be that
* of the extent of the extend page and will be manipulated thru
* an xtExtend() or an xtTailgate(), depending upon whether the
* disk allocation occurred as an inplace extension. the second
* extent will be manipulated (created) through an xtInsert() and
* will be for the pages following the extend page.
*/
if (abnr && (!(xp->flag & XAD_NOTRECORDED)) && (nxlen > nbperpage)) {
ntail = nbperpage;
nextend = ntail - xlen;
ninsert = nxlen - nbperpage;
xflag = XAD_NOTRECORDED;
} else {
ntail = nxlen;
nextend = delta;
ninsert = 0;
xflag = xp->flag;
}
/* if we were able to extend the disk allocation in place,
* extend the extent. otherwise, move the extent to a
* new disk location.
*/
if (xaddr == nxaddr) {
/* extend the extent */
if ((rc = xtExtend(0, ip, xoff + xlen, (int) nextend, 0))) {
dbFree(ip, xaddr + xlen, delta);
dquot_free_block(ip, nxlen);
goto exit;
}
} else {
/*
* move the extent to a new location:
*
* xtTailgate() accounts for relocated tail extent;
*/
if ((rc = xtTailgate(0, ip, xoff, (int) ntail, nxaddr, 0))) {
dbFree(ip, nxaddr, nxlen);
dquot_free_block(ip, nxlen);
goto exit;
}
}
/* check if we need to also insert a new extent */
if (ninsert) {
/* perform the insert. if it fails, free the blocks
* to be inserted and make it appear that we only did
* the xtExtend() or xtTailgate() above.
*/
xaddr = nxaddr + ntail;
if (xtInsert (0, ip, xflag, xoff + ntail, (int) ninsert,
&xaddr, 0)) {
dbFree(ip, xaddr, (s64) ninsert);
delta = nextend;
nxlen = ntail;
xflag = 0;
}
}
/* set the return results */
XADaddress(xp, nxaddr);
XADlength(xp, nxlen);
XADoffset(xp, xoff);
xp->flag = xflag;
mark_inode_dirty(ip);
exit:
mutex_unlock(&JFS_IP(ip)->commit_mutex);
return (rc);
}
#endif /* _NOTYET */
/*
* NAME: extHint()
*
* FUNCTION: produce an extent allocation hint for a file offset.
*
* PARAMETERS:
* ip - the inode of the file.
* offset - file offset for which the hint is needed.
* xp - pointer to the xad that is to be filled in with
* the hint.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error.
*/
int extHint(struct inode *ip, s64 offset, xad_t * xp)
{
struct super_block *sb = ip->i_sb;
int nbperpage = JFS_SBI(sb)->nbperpage;
s64 prev;
int rc = 0;
s64 xaddr;
int xlen;
int xflag;
/* init the hint as "no hint provided" */
XADaddress(xp, 0);
/* determine the starting extent offset of the page previous
* to the page containing the offset.
*/
prev = ((offset & ~POFFSET) >> JFS_SBI(sb)->l2bsize) - nbperpage;
/* if the offset is in the first page of the file, no hint provided.
*/
if (prev < 0)
goto out;
rc = xtLookup(ip, prev, nbperpage, &xflag, &xaddr, &xlen, 0);
if ((rc == 0) && xlen) {
if (xlen != nbperpage) {
jfs_error(ip->i_sb, "corrupt xtree\n");
rc = -EIO;
}
XADaddress(xp, xaddr);
XADlength(xp, xlen);
XADoffset(xp, prev);
/*
* only preserve the abnr flag within the xad flags
* of the returned hint.
*/
xp->flag = xflag & XAD_NOTRECORDED;
} else
rc = 0;
out:
return (rc);
}
/*
* NAME: extRecord()
*
* FUNCTION: change a page with a file from not recorded to recorded.
*
* PARAMETERS:
* ip - inode of the file.
* cp - cbuf of the file page.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error.
* -ENOSPC - insufficient disk resources.
*/
int extRecord(struct inode *ip, xad_t * xp)
{
int rc;
txBeginAnon(ip->i_sb);
mutex_lock(&JFS_IP(ip)->commit_mutex);
/* update the extent */
rc = xtUpdate(0, ip, xp);
mutex_unlock(&JFS_IP(ip)->commit_mutex);
return rc;
}
#ifdef _NOTYET
/*
* NAME: extFill()
*
* FUNCTION: allocate disk space for a file page that represents
* a file hole.
*
* PARAMETERS:
* ip - the inode of the file.
* cp - cbuf of the file page represent the hole.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error.
* -ENOSPC - insufficient disk resources.
*/
int extFill(struct inode *ip, xad_t * xp)
{
int rc, nbperpage = JFS_SBI(ip->i_sb)->nbperpage;
s64 blkno = offsetXAD(xp) >> ip->i_blkbits;
// assert(ISSPARSE(ip));
/* initialize the extent allocation hint */
XADaddress(xp, 0);
/* allocate an extent to fill the hole */
if ((rc = extAlloc(ip, nbperpage, blkno, xp, false)))
return (rc);
assert(lengthPXD(xp) == nbperpage);
return (0);
}
#endif /* _NOTYET */
/*
* NAME: extBalloc()
*
* FUNCTION: allocate disk blocks to form an extent.
*
* initially, we will try to allocate disk blocks for the
* requested size (nblocks). if this fails (nblocks
* contiguous free blocks not available), we'll try to allocate
* a smaller number of blocks (producing a smaller extent), with
* this smaller number of blocks consisting of the requested
* number of blocks rounded down to the next smaller power of 2
* number (i.e. 16 -> 8). we'll continue to round down and
* retry the allocation until the number of blocks to allocate
* is smaller than the number of blocks per page.
*
* PARAMETERS:
* ip - the inode of the file.
* hint - disk block number to be used as an allocation hint.
* *nblocks - pointer to an s64 value. on entry, this value specifies
* the desired number of block to be allocated. on successful
* exit, this value is set to the number of blocks actually
* allocated.
* blkno - pointer to a block address that is filled in on successful
* return with the starting block number of the newly
* allocated block range.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error.
* -ENOSPC - insufficient disk resources.
*/
static int
extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
{
struct jfs_inode_info *ji = JFS_IP(ip);
struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
s64 nb, nblks, daddr, max;
int rc, nbperpage = sbi->nbperpage;
struct bmap *bmp = sbi->bmap;
int ag;
/* get the number of blocks to initially attempt to allocate.
* we'll first try the number of blocks requested unless this
* number is greater than the maximum number of contiguous free
* blocks in the map. in that case, we'll start off with the
* maximum free.
*/
max = (s64) 1 << bmp->db_maxfreebud;
if (*nblocks >= max && *nblocks > nbperpage)
nb = nblks = (max > nbperpage) ? max : nbperpage;
else
nb = nblks = *nblocks;
/* try to allocate blocks */
while ((rc = dbAlloc(ip, hint, nb, &daddr)) != 0) {
/* if something other than an out of space error,
* stop and return this error.
*/
if (rc != -ENOSPC)
return (rc);
/* decrease the allocation request size */
nb = min(nblks, extRoundDown(nb));
/* give up if we cannot cover a page */
if (nb < nbperpage)
return (rc);
}
*nblocks = nb;
*blkno = daddr;
if (S_ISREG(ip->i_mode) && (ji->fileset == FILESYSTEM_I)) {
ag = BLKTOAG(daddr, sbi);
spin_lock_irq(&ji->ag_lock);
if (ji->active_ag == -1) {
atomic_inc(&bmp->db_active[ag]);
ji->active_ag = ag;
} else if (ji->active_ag != ag) {
atomic_dec(&bmp->db_active[ji->active_ag]);
atomic_inc(&bmp->db_active[ag]);
ji->active_ag = ag;
}
spin_unlock_irq(&ji->ag_lock);
}
return (0);
}
#ifdef _NOTYET
/*
* NAME: extBrealloc()
*
* FUNCTION: attempt to extend an extent's allocation.
*
* Initially, we will try to extend the extent's allocation
* in place. If this fails, we'll try to move the extent
* to a new set of blocks. If moving the extent, we initially
* will try to allocate disk blocks for the requested size
* (newnblks). if this fails (new contiguous free blocks not
* available), we'll try to allocate a smaller number of
* blocks (producing a smaller extent), with this smaller
* number of blocks consisting of the requested number of
* blocks rounded down to the next smaller power of 2
* number (i.e. 16 -> 8). We'll continue to round down and
* retry the allocation until the number of blocks to allocate
* is smaller than the number of blocks per page.
*
* PARAMETERS:
* ip - the inode of the file.
* blkno - starting block number of the extents current allocation.
* nblks - number of blocks within the extents current allocation.
* newnblks - pointer to a s64 value. on entry, this value is the
* the new desired extent size (number of blocks). on
* successful exit, this value is set to the extent's actual
* new size (new number of blocks).
* newblkno - the starting block number of the extents new allocation.
*
* RETURN VALUES:
* 0 - success
* -EIO - i/o error.
* -ENOSPC - insufficient disk resources.
*/
static int
extBrealloc(struct inode *ip,
s64 blkno, s64 nblks, s64 * newnblks, s64 * newblkno)
{
int rc;
/* try to extend in place */
if ((rc = dbExtend(ip, blkno, nblks, *newnblks - nblks)) == 0) {
*newblkno = blkno;
return (0);
} else {
if (rc != -ENOSPC)
return (rc);
}
/* in place extension not possible.
* try to move the extent to a new set of blocks.
*/
return (extBalloc(ip, blkno, newnblks, newblkno));
}
#endif /* _NOTYET */
/*
* NAME: extRoundDown()
*
* FUNCTION: round down a specified number of blocks to the next
* smallest power of 2 number.
*
* PARAMETERS:
* nb - the inode of the file.
*
* RETURN VALUES:
* next smallest power of 2 number.
*/
static s64 extRoundDown(s64 nb)
{
int i;
u64 m, k;
for (i = 0, m = (u64) 1 << 63; i < 64; i++, m >>= 1) {
if (m & nb)
break;
}
i = 63 - i;
k = (u64) 1 << i;
k = ((k - 1) & nb) ? k : k >> 1;
return (k);
}