Package: e2fsprogs
Version: 1.43.7-1
Severity: normal
Tags: upstream
Dear Maintainer,
I found a problem with debugfs (but it may be a problem with the whole
e2fslibs) when trying to mark block bitmap. It looks like group
descriptor which is modified with
Steps to reproduce this:
1. Create a new ext4 filesystem image:
$ dd if=/dev/zero of=/tmp/testfs.img bs=1K count=4096
$ /sbin/mkfs.ext4 /tmp/testfs.img
2. Open this image with debugfs, set some free block's mark and close
debugfs:
$ /sbin/debugfs -w /tmp/testfs.img
debugfs: ffb
Free blocks found: 1204
debugfs: setb 1204
debugfs: q
$
3. Try to open this image again with debugfs:
$ /sbin/debugfs /tmp/testfs.img
/tmp/testfs.img: Block bitmap checksum does not match bitmap while
reading block bitmap
debugfs:
This error is also detected with e2fsck.
Some debugging showed that block bitmap checksum is calculated correctly both
when writing a new block bitmap and when opening filesystem. Probably, the
problem is that calculated checksum on writing stage is not actually written
into FS. I put breakpoints into ext2fs_block_bitmap_csum_set and
ext2fs_block_bitmap_csum_verify and it showed up that 'provided'
checksum in 'verify' is the same as it was in gdp in 'set' just after getting
group descriptor.
-- System Information:
Debian Release: buster/sid
APT prefers testing
APT policy: (900, 'testing'), (500, 'testing-debug'), (10, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 4.13.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8),
LANGUAGE=en_US:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages e2fsprogs depends on:
ii e2fslibs 1.43.7-1
ii libblkid1 2.30.2-0.1
ii libc6 2.25-3
ii libcomerr2 1.43.7-1
ii libss2 1.43.7-1
ii libuuid1 2.30.2-0.1
Versions of packages e2fsprogs recommends:
pn e2fsprogs-l10n <none>
Versions of packages e2fsprogs suggests:
pn e2fsck-static <none>
pn fuse2fs <none>
pn gpart <none>
ii parted 3.2-18
-- no debconf information
