linux/fs/btrfs/Kconfig

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# SPDX-License-Identifier: GPL-2.0
config BTRFS_FS
tristate "Btrfs filesystem support"
select CRYPTO
select CRYPTO_CRC32C
select LIBCRC32C
select ZLIB_INFLATE
select ZLIB_DEFLATE
select LZO_COMPRESS
select LZO_DECOMPRESS
btrfs: Add zstd support Add zstd compression and decompression support to BtrFS. zstd at its fastest level compresses almost as well as zlib, while offering much faster compression and decompression, approaching lzo speeds. I benchmarked btrfs with zstd compression against no compression, lzo compression, and zlib compression. I benchmarked two scenarios. Copying a set of files to btrfs, and then reading the files. Copying a tarball to btrfs, extracting it to btrfs, and then reading the extracted files. After every operation, I call `sync` and include the sync time. Between every pair of operations I unmount and remount the filesystem to avoid caching. The benchmark files can be found in the upstream zstd source repository under `contrib/linux-kernel/{btrfs-benchmark.sh,btrfs-extract-benchmark.sh}` [1] [2]. I ran the benchmarks on a Ubuntu 14.04 VM with 2 cores and 4 GiB of RAM. The VM is running on a MacBook Pro with a 3.1 GHz Intel Core i7 processor, 16 GB of RAM, and a SSD. The first compression benchmark is copying 10 copies of the unzipped Silesia corpus [3] into a BtrFS filesystem mounted with `-o compress-force=Method`. The decompression benchmark times how long it takes to `tar` all 10 copies into `/dev/null`. The compression ratio is measured by comparing the output of `df` and `du`. See the benchmark file [1] for details. I benchmarked multiple zstd compression levels, although the patch uses zstd level 1. | Method | Ratio | Compression MB/s | Decompression speed | |---------|-------|------------------|---------------------| | None | 0.99 | 504 | 686 | | lzo | 1.66 | 398 | 442 | | zlib | 2.58 | 65 | 241 | | zstd 1 | 2.57 | 260 | 383 | | zstd 3 | 2.71 | 174 | 408 | | zstd 6 | 2.87 | 70 | 398 | | zstd 9 | 2.92 | 43 | 406 | | zstd 12 | 2.93 | 21 | 408 | | zstd 15 | 3.01 | 11 | 354 | The next benchmark first copies `linux-4.11.6.tar` [4] to btrfs. Then it measures the compression ratio, extracts the tar, and deletes the tar. Then it measures the compression ratio again, and `tar`s the extracted files into `/dev/null`. See the benchmark file [2] for details. | Method | Tar Ratio | Extract Ratio | Copy (s) | Extract (s)| Read (s) | |--------|-----------|---------------|----------|------------|----------| | None | 0.97 | 0.78 | 0.981 | 5.501 | 8.807 | | lzo | 2.06 | 1.38 | 1.631 | 8.458 | 8.585 | | zlib | 3.40 | 1.86 | 7.750 | 21.544 | 11.744 | | zstd 1 | 3.57 | 1.85 | 2.579 | 11.479 | 9.389 | [1] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/btrfs-benchmark.sh [2] https://github.com/facebook/zstd/blob/dev/contrib/linux-kernel/btrfs-extract-benchmark.sh [3] http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia [4] https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-4.11.6.tar.xz zstd source repository: https://github.com/facebook/zstd Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2017-08-10 02:39:02 +00:00
select ZSTD_COMPRESS
select ZSTD_DECOMPRESS
select RAID6_PQ
select XOR_BLOCKS
select SRCU
help
Btrfs is a general purpose copy-on-write filesystem with extents,
writable snapshotting, support for multiple devices and many more
features focused on fault tolerance, repair and easy administration.
The filesystem disk format is no longer unstable, and it's not
expected to change unless there are strong reasons to do so. If there
is a format change, file systems with a unchanged format will
continue to be mountable and usable by newer kernels.
For more information, please see the web pages at
http://btrfs.wiki.kernel.org.
To compile this file system support as a module, choose M here. The
module will be called btrfs.
If unsure, say N.
config BTRFS_FS_POSIX_ACL
bool "Btrfs POSIX Access Control Lists"
depends on BTRFS_FS
select FS_POSIX_ACL
help
POSIX Access Control Lists (ACLs) support permissions for users and
groups beyond the owner/group/world scheme.
If you don't know what Access Control Lists are, say N
config BTRFS_FS_CHECK_INTEGRITY
bool "Btrfs with integrity check tool compiled in (DANGEROUS)"
depends on BTRFS_FS
help
Adds code that examines all block write requests (including
writes of the super block). The goal is to verify that the
state of the filesystem on disk is always consistent, i.e.,
after a power-loss or kernel panic event the filesystem is
in a consistent state.
If the integrity check tool is included and activated in
the mount options, plenty of kernel memory is used, and
plenty of additional CPU cycles are spent. Enabling this
functionality is not intended for normal use.
In most cases, unless you are a btrfs developer who needs
to verify the integrity of (super)-block write requests
during the run of a regression test, say N
config BTRFS_FS_RUN_SANITY_TESTS
bool "Btrfs will run sanity tests upon loading"
depends on BTRFS_FS
help
This will run some basic sanity tests on the free space cache
code to make sure it is acting as it should. These are mostly
regression tests and are only really interesting to btrfs
developers.
If unsure, say N.
config BTRFS_DEBUG
bool "Btrfs debugging support"
depends on BTRFS_FS
help
Enable run-time debugging support for the btrfs filesystem. This may
enable additional and expensive checks with negative impact on
performance, or export extra information via sysfs.
If unsure, say N.
config BTRFS_ASSERT
bool "Btrfs assert support"
depends on BTRFS_FS
help
Enable run-time assertion checking. This will result in panics if
any of the assertions trip. This is meant for btrfs developers only.
If unsure, say N.
config BTRFS_FS_REF_VERIFY
bool "Btrfs with the ref verify tool compiled in"
depends on BTRFS_FS
default n
help
Enable run-time extent reference verification instrumentation. This
is meant to be used by btrfs developers for tracking down extent
reference problems or verifying they didn't break something.
If unsure, say N.