On Mon, Jun 21, 2010 at 10:55:18AM +0800, xiaowei hu wrote:
> Hi,
>
> Recently I was playing with xfsprogs, and did some test on xfs_check
> tools in this mothod:
> 1.make a xfs fs on one partition.
> mkfs.xfs -f /dev/sda2
> 2.randomly modify some blocks on this volume using xfs_db.
> xfs_db -x -c blockget -c "blocktrash -3 -s 36 -n 81" /dev/sda2
> 3.run xfs_check -s
> xfs_check -s /dev/sda2
>
> the output saying:
> [root@test1 ~]# xfs_check -s /dev/sda2
> bad version number 0x78 for inode 135
> bad magic number 0xa855 for inode 154
> bad magic number 0x5024 for inode 165
> /usr/local/bin/xfs_check: line 28: 769 Segmentation fault xfs_db
> $DBOPTS -F -i -p xfs_check -c "blockget$OPTS" $1
>
> if I run xfs_check without -s option, don't have this fault.
>
> Is this a known problem?
No.
> I tried the latest code ,also have this problem.
Yeah, the code determining whether to output a message is broken:
2651 if (!isfree) {
2652 id = find_inode(ino, 1);
2653 bno = XFS_INO_TO_FSB(mp, ino);
2654 blkmap = NULL;
2655 }
find_inode() checks a list created by the "-i <ino #>" command line
option, so will always return NULL for this test case. Most of the checks
do this:
2657 if (!sflag || isfree || id->ilist || CHECK_BLIST(bno))
sflag is set by the "-s" command line option, which is why this
problem requires that to be set - the output checks don't get past
this otherwise.
isfree is a parameter passed into to say whether the inode is
allocated or not. The code hence assumes that if !isfree, then id !=
NULL, which is certainly not the case. Hence it can blow up if id =
NULL.
The line it crashed on:
2670 if (isfree) {
2671 if (idic.di_nblocks != 0) {
2672 >>>>>> if (!sflag || id->ilist || CHECK_BLIST(bno))
Looks like a clear case of copy-n-paste error - if isfree is set, the
id _must_ be null and we go kaboom.
It looks like none of the code in this function actually checks for
whether id is valid or not after find_inode and dereferencing the
reurn pointer.
The patch below should fix the problem.
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
---
db/check.c | 29 ++++++++++++++++-------------
1 files changed, 16 insertions(+), 13 deletions(-)
diff --git a/db/check.c b/db/check.c
index 7620d9c..e0dcf63 100644
--- a/db/check.c
+++ b/db/check.c
@@ -2619,6 +2619,7 @@ process_inode(
xfs_qcnt_t ic = 0;
xfs_qcnt_t rc = 0;
xfs_dqid_t dqprid;
+ int v = 0;
static char okfmts[] = {
0, /* type 0 unused */
1 << XFS_DINODE_FMT_DEV, /* FIFO */
@@ -2653,15 +2654,16 @@ process_inode(
bno = XFS_INO_TO_FSB(mp, ino);
blkmap = NULL;
}
+ v = (!sflag || (id && id->ilist) || CHECK_BLIST(bno));
if (idic.di_magic != XFS_DINODE_MAGIC) {
- if (!sflag || isfree || id->ilist || CHECK_BLIST(bno))
+ if (isfree || v)
dbprintf(_("bad magic number %#x for inode %lld\n"),
idic.di_magic, ino);
error++;
return;
}
if (!XFS_DINODE_GOOD_VERSION(idic.di_version)) {
- if (!sflag || isfree || id->ilist || CHECK_BLIST(bno))
+ if (isfree || v)
dbprintf(_("bad version number %#x for inode %lld\n"),
idic.di_version, ino);
error++;
@@ -2669,7 +2671,7 @@ process_inode(
}
if (isfree) {
if (idic.di_nblocks != 0) {
- if (!sflag || id->ilist || CHECK_BLIST(bno))
+ if (v)
dbprintf(_("bad nblocks %lld for free inode "
"%lld\n"),
idic.di_nblocks, ino);
@@ -2680,21 +2682,22 @@ process_inode(
else
nlink = idic.di_nlink;
if (nlink != 0) {
- if (!sflag || id->ilist || CHECK_BLIST(bno))
+ if (v)
dbprintf(_("bad nlink %d for free inode %lld\n"),
nlink, ino);
error++;
}
if (idic.di_mode != 0) {
- if (!sflag || id->ilist || CHECK_BLIST(bno))
+ if (v)
dbprintf(_("bad mode %#o for free inode %lld\n"),
idic.di_mode, ino);
error++;
}
return;
}
+
if (be32_to_cpu(dip->di_next_unlinked) != NULLAGINO) {
- if (!sflag || isfree || id->ilist || CHECK_BLIST(bno))
+ if (v)
dbprintf(_("bad next unlinked %#x for inode %lld\n"),
be32_to_cpu(dip->di_next_unlinked), ino);
error++;
@@ -2704,27 +2707,27 @@ process_inode(
*/
if ((((idic.di_mode & S_IFMT) >> 12) > 15) ||
(!(okfmts[(idic.di_mode & S_IFMT) >> 12] & (1 << idic.di_format)))) {
- if (!sflag || id->ilist || CHECK_BLIST(bno))
+ if (v)
dbprintf(_("bad format %d for inode %lld type %#o\n"),
idic.di_format, id->ino, idic.di_mode & S_IFMT);
error++;
return;
}
if ((unsigned int)XFS_DFORK_ASIZE(dip, mp) >= XFS_LITINO(mp)) {
- if (!sflag || id->ilist)
+ if (v)
dbprintf(_("bad fork offset %d for inode %lld\n"),
idic.di_forkoff, id->ino);
error++;
return;
}
if ((unsigned int)idic.di_aformat > XFS_DINODE_FMT_BTREE) {
- if (!sflag || id->ilist)
+ if (v)
dbprintf(_("bad attribute format %d for inode %lld\n"),
idic.di_aformat, id->ino);
error++;
return;
}
- if (verbose || id->ilist || CHECK_BLIST(bno))
+ if (verbose || v)
dbprintf(_("inode %lld mode %#o fmt %s "
"afmt %s "
"nex %d anex %d nblk %lld sz %lld%s%s%s%s%s%s%s\n"),
@@ -2844,20 +2847,20 @@ process_inode(
}
totblocks = totdblocks + totiblocks + atotdblocks + atotiblocks;
if (totblocks != idic.di_nblocks) {
- if (!sflag || id->ilist || CHECK_BLIST(bno))
+ if (v)
dbprintf(_("bad nblocks %lld for inode %lld, counted "
"%lld\n"),
idic.di_nblocks, id->ino, totblocks);
error++;
}
if (nextents != idic.di_nextents) {
- if (!sflag || id->ilist || CHECK_BLIST(bno))
+ if (v)
dbprintf(_("bad nextents %d for inode %lld, counted %d\n"),
idic.di_nextents, id->ino, nextents);
error++;
}
if (anextents != idic.di_anextents) {
- if (!sflag || id->ilist || CHECK_BLIST(bno))
+ if (v)
dbprintf(_("bad anextents %d for inode %lld, counted "
"%d\n"),
idic.di_anextents, id->ino, anextents);
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