2aa4085bf7
[BUG]
For a degraded RAID5, btrfs check will fail to even read the chunk root:
# mkfs.btrfs -f -m raid5 -d raid5 $dev1 $dev2 $dev3
# wipefs -fa $dev1
# btrfs check $dev2
Opening filesystem to check...
warning, device 1 is missing
bad tree block 22036480, bytenr mismatch, want=22036480, have=0
ERROR: cannot read chunk root
ERROR: cannot open file system
[CAUSE]
Although read_tree_block() function from btrfs-progs is properly
iterating the mirrors (mirror 1 is reading from the disk directly,
mirror 2 will be rebuild from parity), the raid56 recovery path is not
handling the read error correctly.
The existing code will try to read the full stripe, but any read failure
(including missing device) will immediately cause an error:
for (i = 0; i < num_stripes; i++) {
ret = btrfs_pread(multi->stripes[i].dev->fd, pointers[i],
BTRFS_STRIPE_LEN, multi->stripes[i].physical,
fs_info->zoned);
if (ret < BTRFS_STRIPE_LEN) {
ret = -EIO;
goto out;
}
}
[FIX]
To make failed_a/failed_b calculation much easier, and properly handle
too many missing devices, here this patch will introduce a new bitmap
based solution.
The new @failed_stripe_bitmap will represent all the failed stripes.
So the initial read will mark all the missing devices in the
@failed_stripe_bitmap, and later operations will all operate on that
bitmap.
Only before we call raid56_recov(), we convert the bitmap to the old
failed_a/failed_b interface and continue.
Now btrfs check can handle above case properly:
# btrfs check $dev2
Opening filesystem to check...
warning, device 1 is missing
Checking filesystem on /dev/test/scratch2
UUID: 8b2e1cb4-f35b-4856-9b11-262d39d8458b
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space tree
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
found 147456 bytes used, no error found
total csum bytes: 0
total tree bytes: 147456
total fs tree bytes: 32768
total extent tree bytes: 16384
btree space waste bytes: 139871
file data blocks allocated: 0
referenced 0
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
||
|---|---|---|
| check | ||
| ci | ||
| cmds | ||
| common | ||
| convert | ||
| crypto | ||
| Documentation | ||
| image | ||
| kernel-lib | ||
| kernel-shared | ||
| libbtrfs | ||
| libbtrfsutil | ||
| m4 | ||
| mkfs | ||
| tests | ||
| .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 | ||
| btrfstune.c | ||
| CHANGES | ||
| configure.ac | ||
| COPYING | ||
| fsck.btrfs | ||
| INSTALL | ||
| ioctl.h | ||
| kerncompat.h | ||
| libbtrfs.sym | ||
| Makefile | ||
| Makefile.extrawarn | ||
| Makefile.inc.in | ||
| quick-test.c | ||
| README.md | ||
| show-blocks | ||
| VERSION | ||
| version.h.in | ||
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
See INSTALL for build instructions and tests/README.md for testing 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 wiki.
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
- bugzilla.kernel.org -- (requires registration), set the product to Filesystems and component Btrfs, please put 'btrfs-progs' into the subject so it's clear that it's not a kernel bug report
Development
The patch submissions, development or general discussions take place at linux-btrfs@vger.kernel.org mailinglist, subsciption is not required to post.
The GitHub pull requests will not be accepted directly, the preferred way is to send patches to the mailinglist instead. You can link to a branch in any git repository if the mails do not make it to the mailinglist or just for convenience (makes it easier to test).
The development model of btrfs-progs shares a lot with the kernel model. The github way is different in some ways. We, the upstream community, expect that the patches meet some criteria (often lacking in github contributions):
- 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: 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.
Documents 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 rescure or limited environments harder. The implementations are portable and not optimized for speed nor accelerated. 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.