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pull freebsd's ufs_lookup.c rev.1.53 and 1.54. PR/31873.

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> ----------------------------
> revision 1.54
> date: 2001/08/26 01:25:12;  author: iedowse;  state: Exp;  lines: +30 -12
> When compacting directories, ufs_direnter() always trusted DIRSIZ()
> to supply the number of bytes to be bcopy()'d to move an entry. If
> d_ino == 0 however, DIRSIZ() is not guaranteed to return a sensible
> length, so ufs_direnter could end up corrupting a directory during
> compaction. In practice I believe this can only happen after fsck_ffs
> has fixed a previously-corrupted directory.
>
> We now deal with any mid-block unused entries specially to avoid
> using DIRSIZ() or bcopy() on such entries. We also ensure that the
> variables 'dsize' and 'spacefree' contain meaningful values at all
> times. Add a few comments to describe better this intricate piece
> of code.
>
> The special handling of mid-block unused entries makes the dirhash-
> specific bugfix in the previous revision (1.53) now uncecessary,
> so this change removes it.
>
> Reviewed by:  mckusick
> ----------------------------
> revision 1.53
> date: 2001/08/22 01:35:17;  author: iedowse;  state: Exp;  lines: +2 -2
> When compressing directory blocks, the dirhash code didn't check
> that the directory entry was in use before attempting to find it
> in the hash structures to change its offset. Normally, unused
> entries do not need to be moved, but fsck can leave behind some
> unused entries that do. A dirhash sanity panic resulted when the
> entry to be moved was not found. Add a check that stops entries
> with d_ino == 0 from being passed to ufsdirhash_move().
This commit is contained in:
yamt 2006-01-14 09:09:02 +00:00
parent cabee93abb
commit 3a6eed1f58
1 changed files with 32 additions and 12 deletions
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44
sys/ufs/ufs/ufs_lookup.c
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@ -1,4 +1,4 @@
/* $NetBSD: ufs_lookup.c,v 1.71 2006/01/13 00:50:58 yamt Exp $ */
/* $NetBSD: ufs_lookup.c,v 1.72 2006/01/14 09:09:02 yamt Exp $ */
/*
* Copyright (c) 1989, 1993
@ -37,7 +37,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ufs_lookup.c,v 1.71 2006/01/13 00:50:58 yamt Exp $");
__KERNEL_RCSID(0, "$NetBSD: ufs_lookup.c,v 1.72 2006/01/14 09:09:02 yamt Exp $");
#ifdef _KERNEL_OPT
#include "opt_ffs.h"
@ -908,21 +908,36 @@ ufs_direnter(struct vnode *dvp, struct vnode *tvp, struct direct *dirp,
* dp->i_offset + dp->i_count would yield the space.
*/
ep = (struct direct *)dirbuf;
dsize = DIRSIZ(FSFMT(dvp), ep, needswap);
dsize = ufs_rw32(ep->d_ino, needswap) ?
DIRSIZ(FSFMT(dvp), ep, needswap) : 0;
spacefree = ufs_rw16(ep->d_reclen, needswap) - dsize;
for (loc = ufs_rw16(ep->d_reclen, needswap); loc < dp->i_count; ) {
uint16_t reclen;
nep = (struct direct *)(dirbuf + loc);
if (ep->d_ino) {
/* trim the existing slot */
ep->d_reclen = ufs_rw16(dsize, needswap);
ep = (struct direct *)((char *)ep + dsize);
} else {
/* overwrite; nothing there; header is ours */
spacefree += dsize;
/* Trim the existing slot (NB: dsize may be zero). */
ep->d_reclen = ufs_rw16(dsize, needswap);
ep = (struct direct *)((char *)ep + dsize);
reclen = ufs_rw16(nep->d_reclen, needswap);
loc += reclen;
if (nep->d_ino == 0) {
/*
* A mid-block unused entry. Such entries are
* never created by the kernel, but fsck_ffs
* can create them (and it doesn't fix them).
*
* Add up the free space, and initialise the
* relocated entry since we don't memcpy it.
*/
spacefree += reclen;
ep->d_ino = 0;
dsize = 0;
continue;
}
dsize = DIRSIZ(FSFMT(dvp), nep, needswap);
spacefree += ufs_rw16(nep->d_reclen, needswap) - dsize;
loc += ufs_rw16(nep->d_reclen, needswap);
spacefree += reclen - dsize;
#ifdef UFS_DIRHASH
if (dp->i_dirhash != NULL)
ufsdirhash_move(dp, nep,
@ -936,6 +951,11 @@ ufs_direnter(struct vnode *dvp, struct vnode *tvp, struct direct *dirp,
memcpy((caddr_t)ep, (caddr_t)nep, dsize);
}
/*
* Here, `ep' points to a directory entry containing `dsize' in-use
* bytes followed by `spacefree' unused bytes. If ep->d_ino == 0,
* then the entry is completely unused (dsize == 0). The value
* of ep->d_reclen is always indeterminate.
*
* Update the pointer fields in the previous entry (if any),
* copy in the new entry, and write out the block.
*/