416507904c
[BUG] There is a report that btrfs-convert leads to bad csum for the image file. The reproducer looks like this: (note the 64K block size, it's used to force a certain chunk layout) # touch test.img # truncate -s 10G test.img # mkfs.ext4 -b 64K test.img # btrfs-convert -N 64K test.img # btrfs check --check-data-csum test.img Opening filesystem to check... Checking filesystem on /home/adam/test.img UUID: 39d49537-a9f5-47f1-b6ab-7857707b9133 [1/7] checking root items [2/7] checking extents [3/7] checking free space cache [4/7] checking fs roots [5/7] checking csums against data mirror 1 bytenr 4563140608 csum 0x3f1fa0ef expected csum 0xa4c4c072 mirror 1 bytenr 4563206144 csum 0x55dcf0d3 expected csum 0xa4c4c072 mirror 1 bytenr 4563271680 csum 0x4491b00a expected csum 0xa4c4c072 mirror 1 bytenr 4563337216 csum 0x655d1f61 expected csum 0xa4c4c072 mirror 1 bytenr 4563402752 csum 0xd37114d3 expected csum 0xa4c4c072 mirror 1 bytenr 4563468288 csum 0x4c2dab30 expected csum 0xa4c4c072 mirror 1 bytenr 4563533824 csum 0xa80fceed expected csum 0xa4c4c072 mirror 1 bytenr 4563599360 csum 0xaf610db8 expected csum 0xa4c4c072 mirror 1 bytenr 4563795968 csum 0x67b3c8a0 expected csum 0xa4c4c072 ERROR: errors found in csum tree [6/7] checking root refs ... [CAUSE] Above initial failure is for logical bytenr of 4563140608, which is inside the relocated range of the image file offset [0, 1M). During convert, we migrate the original image file ranges which would later be covered by super and other reserved ranges. The migration happens as: - Read out the original data - Reserve a new file extent - Write the data back to the file extent Note that, the new file extent can be inside some new data chunks, thus it's no longer 1:1 mapped. - Generate the new csum for the new file extent The problem happens at the last stage. We should read out the data from the new file extent, but we call read_disk_extent() using the logical bytenr, however read_disk_extent() is not doing logical -> physical mapping. Thus we will read some garbage, not the newly written data, and use those garbage to generate csum. And caused the above problem. [FIX] Instead of read_disk_extent(), call read_data_from_disk(), which would do the proper logical -> physical mapping, thus would fix the bug. Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
||
|---|---|---|
| .github/workflows | ||
| check | ||
| ci | ||
| cmds | ||
| common | ||
| convert | ||
| crypto | ||
| Documentation | ||
| image | ||
| include | ||
| kernel-lib | ||
| kernel-shared | ||
| libbtrfs | ||
| libbtrfsutil | ||
| m4 | ||
| mkfs | ||
| tests | ||
| tune | ||
| .editorconfig | ||
| .gitignore | ||
| 64-btrfs-dm.rules | ||
| 64-btrfs-zoned.rules | ||
| autogen.sh | ||
| btrfs-completion | ||
| btrfs-corrupt-block.c | ||
| btrfs-crc.c | ||
| btrfs-debugfs | ||
| btrfs-find-root.c | ||
| btrfs-fragments.c | ||
| btrfs-map-logical.c | ||
| btrfs-sb-mod.c | ||
| btrfs-select-super.c | ||
| btrfs.c | ||
| CHANGES | ||
| configure.ac | ||
| COPYING | ||
| fsck.btrfs | ||
| INSTALL | ||
| Makefile | ||
| Makefile.extrawarn | ||
| Makefile.inc.in | ||
| quick-test.c | ||
| README.md | ||
| show-blocks | ||
| VERSION | ||
Btrfs-progs
Userspace utilities to manage btrfs filesystems. License: GPLv2.
Btrfs is a copy on write (COW) filesystem for Linux aimed at implementing advanced features while focusing on fault tolerance, repair and easy administration.
This repository hosts following utilities and also documentation:
- btrfs — the main administration tool (manual page)
- mkfs.btrfs — utility to create the filesystem (manual page)
- all-in-one binary in the busybox style with mkfs.btrfs, btrfs-image and other tools built-in (standalone tools)
- libbtrfsutil (LGPL v2.1) — C and python 3 bindings, see libbtrfsutil/README.md for more
- manual pages and documentation source published at btrfs.readthedocs.io (RTD)
See INSTALL for build instructions, tests/README.md for testing information and ci/README.md for CI information.
Release cycle
The major version releases are time-based and follow the cycle of the linux kernel releases. The cycle usually takes 2 months. A minor version releases may happen in the meantime if there are bug fixes or minor useful improvements queued.
The release tags are signed with a GPG key ID F2B4 1200 C54E FB30 380C 1756 C565 D5F9 D76D 583B,
release tarballs are hosted at kernel.org.
See file CHANGES or changelogs on RTD.
Reporting bugs
There are several ways, each has its own specifics and audience that can give feedback or work on a fix. The following list is sorted in the order of preference:
- github issue tracker
- to the mailing list linux-btrfs@vger.kernel.org -- (not required to subscribe), beware that the mail might get overlooked in other traffic
- IRC (irc.libera.chat #btrfs) -- good for discussions eg. if a bug is already known, but reports could miss developers' attention
- please don't use https://bugzilla.kernel.org for btrfs-progs bugs
Development
The development takes place in the mailing list (linux-btrfs@vger.kernel.org) or at github (issues, pull requests). Changes should be split to logical parts if possible, documentation may be included in the same patch as to code or separately.
The development model of btrfs-progs shares a lot with the kernel model. The
- one logical change per patch: eg. not mixing bugfixes, cleanups, features etc., sometimes it's not clear and will be usually pointed out during reviews
- proper subject line: eg. prefix with btrfs-progs: subpart, ... ,
descriptive yet not too long, see
git log --onelinefor some inspiration - proper changelog: the changelogs are often missing or lacking explanation why the change was made, or how is something broken, what are user-visible effects of the bug or the fix, how does an improvement help or the intended usecase
- the Signed-off-by line is not mandatory for less significant changes
(typos, documentation) but is desired as this documents who authored the
change, you can read more about the
The Developer's Certificate of Origin (chapter 11)
- if you are not used to the signed-off style, your contributions won't be rejected just because of it's missing, the Author: tag will be added as a substitute in order to allow contributions without much bothering with formalities
Source code coding style and preferences follow the
kernel coding style.
You can find the editor settings in .editorconfig and use the
EditorConfig plugin to let your editor use that,
or update your editor settings manually.
Testing
The testing documentation can be found in tests/ and continuous integration/container images in ci/.
Documentation updates
Documentation fixes or updates do not need much explanation so sticking to the code rules in the previous section is not necessary. GitHub pull requests are OK, patches could be sent to me directly and not required to be also in the mailinglist. Pointing out typos via IRC also works, although might get accidentally lost in the noise.
Documentation sources are written in RST and built by sphinx.
Third-party sources
Build dependencies are listed in INSTALL. Implementation of checksum/hash functions is provided by copies of the respective sources to avoid adding dependencies that would make deployments in rescue or limited environments harder. The implementations are portable and there are optimized versions for some architectures. Optionally it's possible to use libgcrypt, libsodium or libkcapi implementations.
- CRC32C: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
- XXHASH: https://github.com/Cyan4973/xxHash
- SHA256: https://tools.ietf.org/html/rfc4634
- BLAKE2: https://github.com/BLAKE2/BLAKE2
Some other code is borrowed from kernel, eg. the raid5 tables or data structure implementation (list, rb-tree).