Manfred Spraul writes:
> Alexander Viro wrote:
> >
> > - Doctor, it hurts when I do it!
> > - Don't do it, then.
> >
> Interesting bugfix:
> have you checked which BUG was triggered?
>
> It's a bug in ext2_free_inode():
> if a io error occurs, then clear_inode() is not called, but
> super_operation.delete_inode() must call clear_inode() before returning.
Here is a patch I sent to Alan and Linus to fix this exact problem last
week.
Cheers, Andreas
==========================================================================
> The below patch adds some extra sanity checks to the root inode when
> mounting an ext2 filesystem. This came about when someone mounted
> a corrupted ext2/RAID partition and subsequently got a kernel BUG
> (see http://marc.theaimsgroup.com/?l=linux-kernel&m=98097024832479&w=4).
> Basically, the first chunk (super.c) checks that the root inode is a
> directory, and has blocks and a size. This would have prevented the
> corrupt filesystem from being mounted in the first place.
> However, the problem that actually caused the BUG is fixed in the
> second chunk (ialloc.c). The BUG was triggered because ext2_free_inode()
> returned without clearing (and setting I_CLEAR) for the inode, hence
> BUG in inode.c:884. We always call clear_inode() now, regardless of
> any other error conditions.
> Cheers, Andreas
===========================================================================
diff -ru linux-2.4.2p4/fs/ext2/super.c linux-2.4.2p4-aed/fs/ext2/super.c
--- linux-2.4.2p4/fs/ext2/super.c Fri Dec 29 15:36:44 2000
+++ linux-2.4.2p4-aed/fs/ext2/super.c Thu Feb 22 11:13:49 2001
@@ -628,13 +625,19 @@
*/
sb->s_op = &ext2_sops;
sb->s_root = d_alloc_root(iget(sb, EXT2_ROOT_INO));
- if (!sb->s_root) {
+ if (!sb->s_root || !S_ISDIR(sb->s_root->d_inode->i_mode) ||
+ !sb->s_root->d_inode->i_blocks || !sb->s_root->d_inode->i_size) {
+ if (sb->s_root) {
+ dput(sb->s_root);
+ sb->s_root = NULL;
+ printk("EXT2-fs: corrupt root inode, run e2fsck\n");
+ } else
+ printk("EXT2-fs: get root inode failed\n");
for (i = 0; i < db_count; i++)
if (sb->u.ext2_sb.s_group_desc[i])
brelse (sb->u.ext2_sb.s_group_desc[i]);
kfree(sb->u.ext2_sb.s_group_desc);
brelse (bh);
- printk ("EXT2-fs: get root inode failed\n");
return NULL;
}
ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
diff -ru linux-2.4.2p4/fs/ext2/ialloc.c linux-2.4.2p4-aed/fs/ext2/ialloc.c
--- linux-2.4.2p4/fs/ext2/ialloc.c Fri Dec 8 18:35:54 2000
+++ linux-2.4.2p4-aed/fs/ext2/ialloc.c Thu Feb 22 11:59:19 2001
@@ -199,10 +199,15 @@
lock_super (sb);
es = sb->u.ext2_sb.s_es;
+ is_directory = S_ISDIR(inode->i_mode);
+
+ /* Do this BEFORE marking the inode not in use */
+ clear_inode(inode);
+
if (ino < EXT2_FIRST_INO(sb) ||
ino > le32_to_cpu(es->s_inodes_count)) {
- ext2_error (sb, "free_inode",
- "reserved inode or nonexistent inode");
+ ext2_error (sb, __FUNCTION__,
+ "reserved or nonexistent inode %ld", ino);
goto error_return;
}
block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
@@ -210,13 +215,8 @@
bitmap_nr = load_inode_bitmap (sb, block_group);
if (bitmap_nr < 0)
goto error_return;
-
+
bh = sb->u.ext2_sb.s_inode_bitmap[bitmap_nr];
-
- is_directory = S_ISDIR(inode->i_mode);
-
- /* Do this BEFORE marking the inode not in use */
- clear_inode (inode);
/* Ok, now we can actually update the inode bitmaps.. */
if (!ext2_clear_bit (bit, bh->b_data))
--
Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto,
\ would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert
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