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Userspace utilities to manage btrfs filesystems
fa13420cc7
The 'end' parameter of check_file_extent tracks the ending offset of the
last checked extent. This is used to detect gaps between adjacent extents.
Currently such gaps are wrongly detected since for regular extents only
the size of the extent is added to the 'end' parameter. This results in
wrongly considering all extents of a file as having gaps between them
when only 2 of them really have a gap as seen in the example below.
Solution:
The extent_end variable should set to the sum of the offset and the
extent_num_bytes of the file extent.
Example:
Suppose that lowmem check the following file extent of inode 257.
item 6 key (257 EXTENT_DATA 0) itemoff 15813 itemsize 53
generation 6 type 1 (regular)
extent data disk byte 13631488 nr 4096
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
item 7 key (257 EXTENT_DATA 8192) itemoff 15760 itemsize 53
generation 6 type 1 (regular)
extent data disk byte 13631488 nr 4096
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
item 8 key (257 EXTENT_DATA 12288) itemoff 15707 itemsize 53
generation 6 type 1 (regular)
extent data disk byte 13631488 nr 4096
extent data offset 0 nr 4096 ram 4096
extent compression 0 (none)
For inode 257, check_inode_item set extent_end to 0, then call
check_file_extent to check item {6,7,8}.
item 6)
offset(0) == extent_end(0)
extent_end = extent_end(0) + extent_num_bytes(4096)
item 7)
offset(8192) != extent_end(4096)
extent_end = extent_end(4096) + extent_num_bytes(4096)
^^^
The old extent_end should replace by offset(8192).
item 8)
offset(12288) != extent_end(8192)
^^^
But there is no gap between item {7,8}.
Fixes:
|
||
|---|---|---|
| check | ||
| convert | ||
| Documentation | ||
| image | ||
| kernel-lib | ||
| kernel-shared | ||
| libbtrfsutil | ||
| m4 | ||
| mkfs | ||
| tests | ||
| travis | ||
| .gitignore | ||
| .travis.yml | ||
| 64-btrfs-dm.rules | ||
| Android.mk | ||
| androidcompat.h | ||
| autogen.sh | ||
| backref.c | ||
| backref.h | ||
| bcp | ||
| btrfs-completion | ||
| btrfs-corrupt-block.c | ||
| btrfs-crc.c | ||
| btrfs-debugfs | ||
| btrfs-find-root.c | ||
| btrfs-fragments.c | ||
| btrfs-list.c | ||
| btrfs-list.h | ||
| btrfs-map-logical.c | ||
| btrfs-sb-mod.c | ||
| btrfs-select-super.c | ||
| btrfs.c | ||
| btrfsck.h | ||
| btrfstune.c | ||
| CHANGES | ||
| chunk-recover.c | ||
| cmds-balance.c | ||
| cmds-device.c | ||
| cmds-fi-du.c | ||
| cmds-fi-usage.c | ||
| cmds-fi-usage.h | ||
| cmds-filesystem.c | ||
| cmds-inspect-dump-super.c | ||
| cmds-inspect-dump-tree.c | ||
| cmds-inspect-tree-stats.c | ||
| cmds-inspect.c | ||
| cmds-property.c | ||
| cmds-qgroup.c | ||
| cmds-quota.c | ||
| cmds-receive.c | ||
| cmds-replace.c | ||
| cmds-rescue.c | ||
| cmds-restore.c | ||
| cmds-scrub.c | ||
| cmds-send.c | ||
| cmds-subvolume.c | ||
| commands.h | ||
| common-defs.h | ||
| configure.ac | ||
| COPYING | ||
| ctree.c | ||
| ctree.h | ||
| delayed-ref.c | ||
| delayed-ref.h | ||
| dir-item.c | ||
| disk-io.c | ||
| disk-io.h | ||
| extent_io.c | ||
| extent_io.h | ||
| extent-cache.c | ||
| extent-cache.h | ||
| extent-tree.c | ||
| file-item.c | ||
| file.c | ||
| find-root.c | ||
| find-root.h | ||
| free-space-cache.c | ||
| free-space-cache.h | ||
| free-space-tree.c | ||
| free-space-tree.h | ||
| fsck.btrfs | ||
| fsfeatures.c | ||
| fsfeatures.h | ||
| hash.h | ||
| hasher.c | ||
| help.c | ||
| help.h | ||
| inode-item.c | ||
| inode-map.c | ||
| inode.c | ||
| INSTALL | ||
| internal.h | ||
| ioctl-test.c | ||
| ioctl.h | ||
| kerncompat.h | ||
| library-test.c | ||
| Makefile | ||
| Makefile.extrawarn | ||
| Makefile.inc.in | ||
| messages.c | ||
| messages.h | ||
| print-tree.c | ||
| print-tree.h | ||
| props.c | ||
| props.h | ||
| qgroup-verify.c | ||
| qgroup-verify.h | ||
| qgroup.c | ||
| qgroup.h | ||
| quick-test.c | ||
| random-test.c | ||
| rbtree-utils.c | ||
| rbtree-utils.h | ||
| README.md | ||
| repair.c | ||
| repair.h | ||
| rescue.h | ||
| root-tree.c | ||
| send-dump.c | ||
| send-dump.h | ||
| send-stream.c | ||
| send-stream.h | ||
| send-utils.c | ||
| send-utils.h | ||
| send.h | ||
| show-blocks | ||
| string-table.c | ||
| string-table.h | ||
| super-recover.c | ||
| task-utils.c | ||
| task-utils.h | ||
| transaction.c | ||
| transaction.h | ||
| utils-lib.c | ||
| utils.c | ||
| utils.h | ||
| uuid-tree.c | ||
| VERSION | ||
| version.h.in | ||
| volumes.c | ||
| volumes.h | ||
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:
- btrfs — the main administration tool (manual page)
- mkfs.btrfs — utility to create the filesystem (manual page)
The C and python 3 bindings are provided by a LGPL library libbtrfsutil see libbtrfsutil/README.md for more.
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.freenode.net #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
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.