On Sep 19, 2007 14:06 +0200, Valerie Clement wrote:
> I ran some tests with the uninit_groups feature enabled and got error messages
> when running e2fsck on my ext4 partition. e2fsck complains of an "invalid
> unused inodes count" in some group descriptors.
> These errors occur when checking groups which have only one inode in use. The
> "free inodes" count has been decremented by one in these groups but not the
> "unused inodes" count.
>
> Index: linux-2.6.23-rc6/fs/ext4/ialloc.c
> ===================================================================
> --- linux-2.6.23-rc6.orig/fs/ext4/ialloc.c 2007-09-19 11:31:01.000000000 +0200
> +++ linux-2.6.23-rc6/fs/ext4/ialloc.c 2007-09-19 11:31:41.000000000 +0200
> @@ -633,13 +633,10 @@ got:
> /* If we didn't allocate from within the initialized part of the inode
> * table then we need to initialize up to this inode. */
> if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
> - if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
> + if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))
> gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
> - free = EXT4_INODES_PER_GROUP(sb);
> - } else {
> - free = EXT4_INODES_PER_GROUP(sb) -
> + free = EXT4_INODES_PER_GROUP(sb) -
> le16_to_cpu(gdp->bg_itable_unused);
> - }
Hmm, this is indeed incorrect, but I'm not sure solution is the right one.
I guess in our testing we ran it for a long time and must have created
more than a single inode per group...
What about the following instead? I think the assumption in the original
code is that "it's a new group, all the inodes are free", but that is not
correct - we want to make NONE of the inodes free initially so that
bt_itable_unused is recalculated below:
if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
- free = EXT4_INODES_PER_GROUP(sb);
+ free = 0;
} else {
free = EXT4_INODES_PER_GROUP(sb) -
le16_to_cpu(gdp->bg_itable_unused);
}
if (ino > free)
gdp->bg_itable_unused =
cpu_to_le16(EXT3_INODES_PER_GROUP(sb) - ino);
Still a bit uneasy about off-by-one errors here though. Is "ino" 0 or
1 for the first inode in the group. We might need to have a -1 in the
bg_itable_unused calculation still.
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
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