On 2010-09-01, at 16:01, Justin Maggard wrote:
> I've mentioned this before on here, but I never verified whether or
> not it was actually broken. I have done so today. I manually
> modified the block count of a 3TB file using debugfs, then ran e2fsck
> on it. e2fsck claimed to repair it, but would throw an error on every
> subsequent e2fsck run for the same issue. The reason is
> inode->osd2.linux2.l_i_blocks_hi is always set to 0 if e2fsck is told
> to fix it. This is an issue in both stable 1.41.12, and in master.
> This patch fixes it for me, but is there anything else that needs to
> get checked here?
It probably makes sense to audit all uses of "i_blocks" to see if they behave similarly badly w.r.t. l_i_blocks_hi. A casual glance indicates that there are a number of places that are similarly broken.
I see there is a helper function e2fsck/blknum.c:ext2fs_inode_i_blocks() that should be used for most i_blocks accesses (excluding those places in e2fsck that check for l_i_blocks_hi being non-zero without the appropriate feature flag being set). It might make sense to rename this function ext2fs_inode_i_blocks_get() and add similar ext2fs_inode_i_blocks_set() routine to set it correctly.
> diff -urp e2fsprogs-1.41.12/e2fsck/pass1.c e2fsprogs-1.41.12-jm/e2fsck/pass1.c
> --- e2fsprogs-1.41.12/e2fsck/pass1.c 2010-05-14 14:51:21.000000000 -0700
> +++ e2fsprogs-1.41.12-jm/e2fsck/pass1.c 2010-09-01 15:54:42.000000000 -0700
> @@ -2044,7 +2044,7 @@ static void check_blocks(e2fsck_t ctx, s
> pctx->num = pb.num_blocks;
> if (fix_problem(ctx, PR_1_BAD_I_BLOCKS, pctx)) {
> inode->i_blocks = pb.num_blocks;
> - inode->osd2.linux2.l_i_blocks_hi = 0;
> + inode->osd2.linux2.l_i_blocks_hi = (pb.num_blocks >> 32);
> dirty_inode++;
> }
> pctx->num = 0;
>
> -Justin
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
Cheers, Andreas
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
