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https://github.com/torvalds/linux
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![Alexei Filippov](/assets/img/avatar_default.png)
The lack of checking bmp->db_max_freebud in extBalloc() can lead to
shift out of bounds, so this patch prevents undefined behavior, because
bmp->db_max_freebud == -1 only if there is no free space.
Signed-off-by: Aleksei Filippov <halip0503@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Fixes: 1da177e4c3
("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+5f088f29593e6b4c8db8@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?id=01abadbd6ae6a08b1f1987aa61554c6b3ac19ff2
389 lines
9.8 KiB
C
389 lines
9.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) International Business Machines Corp., 2000-2004
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*/
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#include <linux/fs.h>
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#include <linux/quotaops.h>
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#include "jfs_incore.h"
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#include "jfs_inode.h"
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#include "jfs_superblock.h"
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#include "jfs_dmap.h"
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#include "jfs_extent.h"
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#include "jfs_debug.h"
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/*
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* forward references
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*/
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static int extBalloc(struct inode *, s64, s64 *, s64 *);
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static s64 extRoundDown(s64 nb);
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#define DPD(a) (printk("(a): %d\n",(a)))
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#define DPC(a) (printk("(a): %c\n",(a)))
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#define DPL1(a) \
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{ \
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if ((a) >> 32) \
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printk("(a): %x%08x ",(a)); \
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else \
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printk("(a): %x ",(a) << 32); \
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}
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#define DPL(a) \
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{ \
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if ((a) >> 32) \
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printk("(a): %x%08x\n",(a)); \
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else \
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printk("(a): %x\n",(a) << 32); \
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}
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#define DPD1(a) (printk("(a): %d ",(a)))
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#define DPX(a) (printk("(a): %08x\n",(a)))
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#define DPX1(a) (printk("(a): %08x ",(a)))
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#define DPS(a) (printk("%s\n",(a)))
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#define DPE(a) (printk("\nENTERING: %s\n",(a)))
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#define DPE1(a) (printk("\nENTERING: %s",(a)))
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#define DPS1(a) (printk(" %s ",(a)))
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/*
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* NAME: extAlloc()
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*
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* FUNCTION: allocate an extent for a specified page range within a
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* file.
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*
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* PARAMETERS:
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* ip - the inode of the file.
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* xlen - requested extent length.
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* pno - the starting page number with the file.
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* xp - pointer to an xad. on entry, xad describes an
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* extent that is used as an allocation hint if the
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* xaddr of the xad is non-zero. on successful exit,
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* the xad describes the newly allocated extent.
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* abnr - bool indicating whether the newly allocated extent
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* should be marked as allocated but not recorded.
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*
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* RETURN VALUES:
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* 0 - success
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* -EIO - i/o error.
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* -ENOSPC - insufficient disk resources.
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*/
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int
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extAlloc(struct inode *ip, s64 xlen, s64 pno, xad_t * xp, bool abnr)
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{
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struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
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s64 nxlen, nxaddr, xoff, hint, xaddr = 0;
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int rc;
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int xflag;
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/* This blocks if we are low on resources */
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txBeginAnon(ip->i_sb);
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/* Avoid race with jfs_commit_inode() */
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mutex_lock(&JFS_IP(ip)->commit_mutex);
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/* validate extent length */
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if (xlen > MAXXLEN)
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xlen = MAXXLEN;
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/* get the page's starting extent offset */
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xoff = pno << sbi->l2nbperpage;
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/* check if an allocation hint was provided */
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if ((hint = addressXAD(xp))) {
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/* get the size of the extent described by the hint */
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nxlen = lengthXAD(xp);
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/* check if the hint is for the portion of the file
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* immediately previous to the current allocation
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* request and if hint extent has the same abnr
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* value as the current request. if so, we can
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* extend the hint extent to include the current
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* extent if we can allocate the blocks immediately
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* following the hint extent.
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*/
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if (offsetXAD(xp) + nxlen == xoff &&
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abnr == ((xp->flag & XAD_NOTRECORDED) ? true : false))
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xaddr = hint + nxlen;
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/* adjust the hint to the last block of the extent */
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hint += (nxlen - 1);
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}
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/* allocate the disk blocks for the extent. initially, extBalloc()
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* will try to allocate disk blocks for the requested size (xlen).
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* if this fails (xlen contiguous free blocks not available), it'll
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* try to allocate a smaller number of blocks (producing a smaller
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* extent), with this smaller number of blocks consisting of the
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* requested number of blocks rounded down to the next smaller
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* power of 2 number (i.e. 16 -> 8). it'll continue to round down
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* and retry the allocation until the number of blocks to allocate
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* is smaller than the number of blocks per page.
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*/
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nxlen = xlen;
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if ((rc = extBalloc(ip, hint ? hint : INOHINT(ip), &nxlen, &nxaddr))) {
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mutex_unlock(&JFS_IP(ip)->commit_mutex);
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return (rc);
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}
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/* Allocate blocks to quota. */
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rc = dquot_alloc_block(ip, nxlen);
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if (rc) {
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dbFree(ip, nxaddr, (s64) nxlen);
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mutex_unlock(&JFS_IP(ip)->commit_mutex);
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return rc;
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}
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/* determine the value of the extent flag */
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xflag = abnr ? XAD_NOTRECORDED : 0;
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/* if we can extend the hint extent to cover the current request,
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* extend it. otherwise, insert a new extent to
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* cover the current request.
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*/
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if (xaddr && xaddr == nxaddr)
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rc = xtExtend(0, ip, xoff, (int) nxlen, 0);
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else
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rc = xtInsert(0, ip, xflag, xoff, (int) nxlen, &nxaddr, 0);
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/* if the extend or insert failed,
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* free the newly allocated blocks and return the error.
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*/
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if (rc) {
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dbFree(ip, nxaddr, nxlen);
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dquot_free_block(ip, nxlen);
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mutex_unlock(&JFS_IP(ip)->commit_mutex);
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return (rc);
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}
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/* set the results of the extent allocation */
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XADaddress(xp, nxaddr);
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XADlength(xp, nxlen);
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XADoffset(xp, xoff);
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xp->flag = xflag;
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mark_inode_dirty(ip);
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mutex_unlock(&JFS_IP(ip)->commit_mutex);
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/*
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* COMMIT_SyncList flags an anonymous tlock on page that is on
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* sync list.
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* We need to commit the inode to get the page written to the disk.
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*/
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if (test_and_clear_cflag(COMMIT_Synclist,ip))
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jfs_commit_inode(ip, 0);
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return (0);
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}
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/*
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* NAME: extHint()
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*
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* FUNCTION: produce an extent allocation hint for a file offset.
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*
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* PARAMETERS:
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* ip - the inode of the file.
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* offset - file offset for which the hint is needed.
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* xp - pointer to the xad that is to be filled in with
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* the hint.
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*
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* RETURN VALUES:
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* 0 - success
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* -EIO - i/o error.
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*/
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int extHint(struct inode *ip, s64 offset, xad_t * xp)
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{
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struct super_block *sb = ip->i_sb;
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int nbperpage = JFS_SBI(sb)->nbperpage;
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s64 prev;
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int rc = 0;
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s64 xaddr;
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int xlen;
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int xflag;
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/* init the hint as "no hint provided" */
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XADaddress(xp, 0);
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/* determine the starting extent offset of the page previous
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* to the page containing the offset.
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*/
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prev = ((offset & ~POFFSET) >> JFS_SBI(sb)->l2bsize) - nbperpage;
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/* if the offset is in the first page of the file, no hint provided.
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*/
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if (prev < 0)
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goto out;
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rc = xtLookup(ip, prev, nbperpage, &xflag, &xaddr, &xlen, 0);
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if ((rc == 0) && xlen) {
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if (xlen != nbperpage) {
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jfs_error(ip->i_sb, "corrupt xtree\n");
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rc = -EIO;
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}
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XADaddress(xp, xaddr);
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XADlength(xp, xlen);
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XADoffset(xp, prev);
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/*
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* only preserve the abnr flag within the xad flags
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* of the returned hint.
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*/
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xp->flag = xflag & XAD_NOTRECORDED;
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} else
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rc = 0;
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out:
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return (rc);
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}
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/*
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* NAME: extRecord()
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*
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* FUNCTION: change a page with a file from not recorded to recorded.
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*
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* PARAMETERS:
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* ip - inode of the file.
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* cp - cbuf of the file page.
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*
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* RETURN VALUES:
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* 0 - success
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* -EIO - i/o error.
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* -ENOSPC - insufficient disk resources.
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*/
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int extRecord(struct inode *ip, xad_t * xp)
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{
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int rc;
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txBeginAnon(ip->i_sb);
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mutex_lock(&JFS_IP(ip)->commit_mutex);
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/* update the extent */
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rc = xtUpdate(0, ip, xp);
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mutex_unlock(&JFS_IP(ip)->commit_mutex);
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return rc;
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}
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/*
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* NAME: extBalloc()
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*
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* FUNCTION: allocate disk blocks to form an extent.
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*
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* initially, we will try to allocate disk blocks for the
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* requested size (nblocks). if this fails (nblocks
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* contiguous free blocks not available), we'll try to allocate
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* a smaller number of blocks (producing a smaller extent), with
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* this smaller number of blocks consisting of the requested
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* number of blocks rounded down to the next smaller power of 2
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* number (i.e. 16 -> 8). we'll continue to round down and
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* retry the allocation until the number of blocks to allocate
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* is smaller than the number of blocks per page.
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*
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* PARAMETERS:
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* ip - the inode of the file.
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* hint - disk block number to be used as an allocation hint.
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* *nblocks - pointer to an s64 value. on entry, this value specifies
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* the desired number of block to be allocated. on successful
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* exit, this value is set to the number of blocks actually
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* allocated.
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* blkno - pointer to a block address that is filled in on successful
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* return with the starting block number of the newly
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* allocated block range.
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*
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* RETURN VALUES:
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* 0 - success
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* -EIO - i/o error.
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* -ENOSPC - insufficient disk resources.
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*/
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static int
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extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
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{
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struct jfs_inode_info *ji = JFS_IP(ip);
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struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
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s64 nb, nblks, daddr, max;
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int rc, nbperpage = sbi->nbperpage;
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struct bmap *bmp = sbi->bmap;
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int ag;
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/* get the number of blocks to initially attempt to allocate.
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* we'll first try the number of blocks requested unless this
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* number is greater than the maximum number of contiguous free
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* blocks in the map. in that case, we'll start off with the
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* maximum free.
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*/
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/* give up if no space left */
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if (bmp->db_maxfreebud == -1)
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return -ENOSPC;
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max = (s64) 1 << bmp->db_maxfreebud;
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if (*nblocks >= max && *nblocks > nbperpage)
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nb = nblks = (max > nbperpage) ? max : nbperpage;
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else
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nb = nblks = *nblocks;
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/* try to allocate blocks */
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while ((rc = dbAlloc(ip, hint, nb, &daddr)) != 0) {
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/* if something other than an out of space error,
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* stop and return this error.
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*/
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if (rc != -ENOSPC)
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return (rc);
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/* decrease the allocation request size */
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nb = min(nblks, extRoundDown(nb));
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/* give up if we cannot cover a page */
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if (nb < nbperpage)
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return (rc);
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}
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*nblocks = nb;
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*blkno = daddr;
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if (S_ISREG(ip->i_mode) && (ji->fileset == FILESYSTEM_I)) {
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ag = BLKTOAG(daddr, sbi);
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spin_lock_irq(&ji->ag_lock);
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if (ji->active_ag == -1) {
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atomic_inc(&bmp->db_active[ag]);
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ji->active_ag = ag;
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} else if (ji->active_ag != ag) {
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atomic_dec(&bmp->db_active[ji->active_ag]);
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atomic_inc(&bmp->db_active[ag]);
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ji->active_ag = ag;
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}
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spin_unlock_irq(&ji->ag_lock);
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}
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return (0);
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}
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/*
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* NAME: extRoundDown()
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*
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* FUNCTION: round down a specified number of blocks to the next
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* smallest power of 2 number.
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*
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* PARAMETERS:
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* nb - the inode of the file.
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*
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* RETURN VALUES:
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* next smallest power of 2 number.
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*/
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static s64 extRoundDown(s64 nb)
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{
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int i;
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u64 m, k;
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for (i = 0, m = (u64) 1 << 63; i < 64; i++, m >>= 1) {
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if (m & nb)
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break;
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}
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i = 63 - i;
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k = (u64) 1 << i;
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k = ((k - 1) & nb) ? k : k >> 1;
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return (k);
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}
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