Hi Stephen and Andrew,
please find attached fixes for three bugs I found while looking into this.
Andrew, could you please push these fixes to Linus? Thanks!
The bug Stephen has triggered is in fs/jbd/transaction.c:
Index: linux-2.5.75/fs/jbd/transaction.c
===================================================================
--- linux-2.5.75.orig/fs/jbd/transaction.c 2003-07-10 22:06:58.000000000
+0200
+++ linux-2.5.75/fs/jbd/transaction.c 2003-07-12 21:31:31.000000000 +0200
@@ -747,7 +747,7 @@
/* We do not want to get caught playing with fields which the
* log thread also manipulates. Make sure that the buffer
* completes any outstanding IO before proceeding. */
- rc = do_get_write_access(handle, jh, 0, NULL);
+ rc = do_get_write_access(handle, jh, 0, credits);
journal_put_journal_head(jh);
return rc;
}
While looking into this issue I found two more bugs in fs/ext3/xattr.c. Fix
below.
- ext3_journal_get_write_access_credits failures break out of the loop in
1058, so <ce> is not released properly.
- <credits> must be reset after journal_release_buffer() in line 1072.
Index: linux-2.5.75/fs/ext3/xattr.c
===================================================================
--- linux-2.5.75.orig/fs/ext3/xattr.c 2003-07-12 13:36:51.000000000 +0200
+++ linux-2.5.75/fs/ext3/xattr.c 2003-07-12 21:35:57.000000000 +0200
@@ -1050,12 +1050,10 @@
ext3_error(inode->i_sb, "ext3_xattr_cache_find",
"inode %ld: block %ld read error",
inode->i_ino, (unsigned long) ce->e_block);
- } else {
+ } else if (ext3_journal_get_write_access_credits(
+ handle, bh, credits) == 0) {
/* ext3_journal_get_write_access() requires an
unlocked
* bh, which complicates things here. */
- if (ext3_journal_get_write_access_credits(handle, bh,
- credits) !=
0)
- return NULL;
lock_buffer(bh);
if (le32_to_cpu(HDR(bh)->h_refcount) >
EXT3_XATTR_REFCOUNT_MAX) {
@@ -1070,6 +1068,7 @@
}
unlock_buffer(bh);
journal_release_buffer(handle, bh, *credits);
+ *credits = 0;
brelse(bh);
}
ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev,
hash);
On Friday 11 July 2003 22:41, Stephen Smalley wrote:
> I've encountered a kernel BUG in jbd during setxattr on 2.5.75, likely
> related to the recent xattr locking changes. Originally encountered
> with SELinux enabled, but also occurs with SELinux disabled. I have not
> been able to reproduce it with 2.5.74.
>
> [...]
>
> A command for reproducing the bug is:
> find . -exec setfattr -n security.selinux -v system_u:object_r:staff_home_t
> {} \;
I could reproduce with user.* attributes as well.
Cheers,
Andreas.
------------------------------------------------------------------
Andreas Gruenbacher SuSE Labs, SuSE Linux AG
mailto:agruen@suse.de Deutschherrnstr. 15-19
http://www.suse.de/ D-90429 Nuernberg, Germany
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