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The checkpoint loop always used (multiples of) lfs_sepb as the number 

of segments to mark. However, this may be much more than lfs_nseg.

Originally this wasn't a big problem, since only the structures in the
diskblock were changed, but nowadays there's a mirror of the segflags
in the in-core superblock. This problem caused the code to walk
way past the end of that allocated area, causing memory corruption
in other kernel structures. So, use lfs_nseg as the maximum, as it should be.

While here, simplify the loop; it had become an obfuscated piece of
code overtime.
This commit is contained in:
fvdl 2003-03-28 22:39:42 +00:00
parent 0ed8d3ba23
commit 691b2fa7db
1 changed files with 16 additions and 30 deletions
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46
sys/ufs/lfs/lfs_segment.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: lfs_segment.c,v 1.116 2003/03/28 08:03:38 perseant Exp $ */
/* $NetBSD: lfs_segment.c,v 1.117 2003/03/28 22:39:42 fvdl Exp $ */
/*-
* Copyright (c) 1999, 2000, 2001, 2002, 2003 The NetBSD Foundation, Inc.
@ -71,7 +71,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: lfs_segment.c,v 1.116 2003/03/28 08:03:38 perseant Exp $");
__KERNEL_RCSID(0, "$NetBSD: lfs_segment.c,v 1.117 2003/03/28 22:39:42 fvdl Exp $");
#define ivndebug(vp,str) printf("ino %d: %s\n",VTOI(vp)->i_number,(str))
@ -537,12 +537,11 @@ lfs_segwrite(struct mount *mp, int flags)
struct segment *sp;
struct vnode *vp;
SEGUSE *segusep;
daddr_t ibno;
int do_ckp, did_ckp, error, i, s;
int do_ckp, did_ckp, error, s;
unsigned n, segleft, maxseg, sn, i, curseg;
int writer_set = 0;
int dirty;
int redo;
int sn;
fs = VFSTOUFS(mp)->um_lfs;
@ -598,17 +597,20 @@ lfs_segwrite(struct mount *mp, int flags)
* last checkpoint as no longer ACTIVE.
*/
if (do_ckp) {
for (ibno = fs->lfs_cleansz + fs->lfs_segtabsz;
--ibno >= fs->lfs_cleansz; ) {
segleft = fs->lfs_nseg;
curseg = 0;
for (n = 0; n < fs->lfs_segtabsz; n++) {
dirty = 0;
if (bread(fs->lfs_ivnode, ibno, fs->lfs_bsize, NOCRED, &bp))
if (bread(fs->lfs_ivnode,
fs->lfs_cleansz + n, fs->lfs_bsize, NOCRED, &bp))
panic("lfs_segwrite: ifile read");
segusep = (SEGUSE *)bp->b_data;
for (i = fs->lfs_sepb; i > 0; i--) {
sn = (ibno - fs->lfs_cleansz) * fs->lfs_sepb +
fs->lfs_sepb - i;
if (segusep->su_flags & SEGUSE_ACTIVE) {
maxseg = min(segleft, fs->lfs_sepb);
for (i = 0; i < maxseg; i++) {
sn = curseg + i;
if (sn != fs->lfs_curseg &&
segusep->su_flags & SEGUSE_ACTIVE) {
segusep->su_flags &= ~SEGUSE_ACTIVE;
--fs->lfs_nactive;
++dirty;
@ -622,28 +624,12 @@ lfs_segwrite(struct mount *mp, int flags)
((SEGUSE_V1 *)segusep + 1);
}
/* But the current segment is still ACTIVE */
segusep = (SEGUSE *)bp->b_data;
if (dtosn(fs, fs->lfs_curseg) / fs->lfs_sepb ==
(ibno-fs->lfs_cleansz)) {
sn = dtosn(fs, fs->lfs_curseg);
if (fs->lfs_version > 1)
segusep[sn % fs->lfs_sepb].su_flags |=
SEGUSE_ACTIVE;
else
((SEGUSE *)
((SEGUSE_V1 *)(bp->b_data) +
(sn % fs->lfs_sepb)))->su_flags
|= SEGUSE_ACTIVE;
fs->lfs_suflags[fs->lfs_activesb][sn] |=
SEGUSE_ACTIVE;
++fs->lfs_nactive;
--dirty;
}
if (dirty)
error = LFS_BWRITE_LOG(bp); /* Ifile */
else
brelse(bp);
segleft -= fs->lfs_sepb;
curseg += fs->lfs_sepb;
}
}