MAINTAINERS: remove links to obsolete btrfs.wiki.kernel.org

The wiki has been archived and is not updated anymore. Remove or replace
the links in files that contain it (MAINTAINERS, Kconfig, docs).

MAINTAINERS: remove links to obsolete btrfs.wiki.kernel.org

The wiki has been archived and is not updated anymore. Remove or replace
the links in files that contain it (MAINTAINERS, Kconfig, docs).

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: deprecate integrity checker feature

The integrity checker feature needs to be enabled at compile time
(BTRFS_FS_CHECK_INTEGRITY) and then enabled by mount options check_int*.

Although it pro

btrfs: deprecate integrity checker feature

The integrity checker feature needs to be enabled at compile time
(BTRFS_FS_CHECK_INTEGRITY) and then enabled by mount options check_int*.

Although it provides some unique features which can not be provided by
any other sanity checks like tree-checker, it does not only have high
CPU and memory overhead, but is also a maintenance burden.

For example, it's the only caller of btrfs_map_block() with
@need_raid_map = 0.

Considering most btrfs developers are not even testing this feature, I'm
here to propose deprecation of this feature.

For now only warning messages will be printed, the feature itself would
still work.

Removal time has been set to 6.7 release.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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block: make blkcg_punt_bio_submit optional

Guard all the code to punt bios to a per-cgroup submission helper by a
new CONFIG_BLK_CGROUP_PUNT_BIO symbol that is selected by btrfs.
This way non-btrfs

block: make blkcg_punt_bio_submit optional

Guard all the code to punt bios to a per-cgroup submission helper by a
new CONFIG_BLK_CGROUP_PUNT_BIO symbol that is selected by btrfs.
This way non-btrfs kernel builds don't need to have this code.

Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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fs/btrfs: Remove "select SRCU"

Now that the SRCU Kconfig option is unconditionally selected, there is
no longer any point in selecting it. Therefore, remove the "select SRCU"
Kconfig statements.

S

fs/btrfs: Remove "select SRCU"

Now that the SRCU Kconfig option is unconditionally selected, there is
no longer any point in selecting it. Therefore, remove the "select SRCU"
Kconfig statements.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: David Sterba <dsterba@suse.com>
Cc: <linux-btrfs@vger.kernel.org>
Acked-by: David Sterba <dsterba@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>

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btrfs: use generic Kconfig option for 256kB page size limit

Use the newly introduced CONFIG_PAGE_SIZE_LESS_THAN_256KB to describe
the dependency introduced by commit b05fbcc36be1 ("btrfs: disable bu

btrfs: use generic Kconfig option for 256kB page size limit

Use the newly introduced CONFIG_PAGE_SIZE_LESS_THAN_256KB to describe
the dependency introduced by commit b05fbcc36be1 ("btrfs: disable build
on platforms having page size 256K").

Link: https://lkml.kernel.org/r/20211129230141.228085-3-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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btrfs: disable build on platforms having page size 256K

With a config having PAGE_SIZE set to 256K, BTRFS build fails
with the following message

include/linux/compiler_types.h:326:38: error: call

btrfs: disable build on platforms having page size 256K

With a config having PAGE_SIZE set to 256K, BTRFS build fails
with the following message

include/linux/compiler_types.h:326:38: error: call to
'__compiletime_assert_791' declared with attribute error:
BUILD_BUG_ON failed: (BTRFS_MAX_COMPRESSED % PAGE_SIZE) != 0

BTRFS_MAX_COMPRESSED being 128K, BTRFS cannot support platforms with
256K pages at the time being.

There are two platforms that can select 256K pages:
- hexagon
- powerpc

Disable BTRFS when 256K page size is selected. Supporting this would
require changes to the subpage mode that's currently being developed.
Given that 256K is many times larger than page sizes commonly used and
for what the algorithms and structures have been tuned, it's out of
scope and disabling build is a reasonable option.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: disable build on platforms having page size 256K

[ Upstream commit b05fbcc36be1f8597a1febef4892053a0b2f3f60 ]

With a config having PAGE_SIZE set to 256K, BTRFS build fails
with the following

btrfs: disable build on platforms having page size 256K

[ Upstream commit b05fbcc36be1f8597a1febef4892053a0b2f3f60 ]

With a config having PAGE_SIZE set to 256K, BTRFS build fails
with the following message

include/linux/compiler_types.h:326:38: error: call to
'__compiletime_assert_791' declared with attribute error:
BUILD_BUG_ON failed: (BTRFS_MAX_COMPRESSED % PAGE_SIZE) != 0

BTRFS_MAX_COMPRESSED being 128K, BTRFS cannot support platforms with
256K pages at the time being.

There are two platforms that can select 256K pages:
- hexagon
- powerpc

Disable BTRFS when 256K page size is selected. Supporting this would
require changes to the subpage mode that's currently being developed.
Given that 256K is many times larger than page sizes commonly used and
for what the algorithms and structures have been tuned, it's out of
scope and disabling build is a reasonable option.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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btrfs: switch to iomap for direct IO

We're using direct io implementation based on buffer heads. This patch
switches to the new iomap infrastructure.

Switch from __blockdev_direct_IO() to iomap_dio

btrfs: switch to iomap for direct IO

We're using direct io implementation based on buffer heads. This patch
switches to the new iomap infrastructure.

Switch from __blockdev_direct_IO() to iomap_dio_rw(). Rename
btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it as
iomap_begin() for iomap direct I/O functions. This function allocates
and locks all the blocks required for the I/O. btrfs_submit_direct() is
used as the submit_io() hook for direct I/O ops.

Since we need direct I/O reads to go through iomap_dio_rw(), we change
file_operations.read_iter() to a btrfs_file_read_iter() which calls
btrfs_direct_IO() for direct reads and falls back to
generic_file_buffered_read() for incomplete reads and buffered reads.

We don't need address_space.direct_IO() anymore: set it to noop.

Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is
capable of direct I/O reads from a hole, so we don't need to return
-ENOENT.

Btrfs direct I/O is now done under i_rwsem, shared in case of reads and
exclusive in case of writes. This guards against simultaneous truncates.

Use iomap->iomap_end() to check for failed or incomplete direct I/O:

- for writes, call __endio_write_update_ordered()
- for reads, unlock extents

btrfs_dio_data is now hooked in iomap->private and not
current->journal_info. It carries the reservation variable and the
amount of data submitted, so we can calculate the amount of data to call
__endio_write_update_ordered in case of an error.

This patch removes last use of struct buffer_head from btrfs.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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Revert "btrfs: switch to iomap_dio_rw() for dio"

This reverts commit a43a67a2d715540c1368b9501a22b0373b5874c0.

This patch reverts the main part of switching direct io implementation
to iomap infras

Revert "btrfs: switch to iomap_dio_rw() for dio"

This reverts commit a43a67a2d715540c1368b9501a22b0373b5874c0.

This patch reverts the main part of switching direct io implementation
to iomap infrastructure. There's a problem in invalidate page that
couldn't be solved as regression in this development cycle.

The problem occurs when buffered and direct io are mixed, and the ranges
overlap. Although this is not recommended, filesystems implement
measures or fallbacks to make it somehow work. In this case, fallback to
buffered IO would be an option for btrfs (this already happens when
direct io is done on compressed data), but the change would be needed in
the iomap code, bringing new semantics to other filesystems.

Another problem arises when again the buffered and direct ios are mixed,
invalidation fails, then -EIO is set on the mapping and fsync will fail,
though there's no real error.

There have been discussions how to fix that, but revert seems to be the
least intrusive option.

Link: https://lore.kernel.org/linux-btrfs/20200528192103.xm45qoxqmkw7i5yl@fiona/
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: switch to iomap_dio_rw() for dio

Switch from __blockdev_direct_IO() to iomap_dio_rw().
Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it
as iomap_begin() for iomap direct

btrfs: switch to iomap_dio_rw() for dio

Switch from __blockdev_direct_IO() to iomap_dio_rw().
Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it
as iomap_begin() for iomap direct I/O functions. This function
allocates and locks all the blocks required for the I/O.
btrfs_submit_direct() is used as the submit_io() hook for direct I/O
ops.

Since we need direct I/O reads to go through iomap_dio_rw(), we change
file_operations.read_iter() to a btrfs_file_read_iter() which calls
btrfs_direct_IO() for direct reads and falls back to
generic_file_buffered_read() for incomplete reads and buffered reads.

We don't need address_space.direct_IO() anymore so set it to noop.
Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is
capable of direct I/O reads from a hole, so we don't need to return
-ENOENT.

BTRFS direct I/O is now done under i_rwsem, shared in case of reads and
exclusive in case of writes. This guards against simultaneous truncates.

Use iomap->iomap_end() to check for failed or incomplete direct I/O:
- for writes, call __endio_write_update_ordered()
- for reads, unlock extents

btrfs_dio_data is now hooked in iomap->private and not
current->journal_info. It carries the reservation variable and the
amount of data submitted, so we can calculate the amount of data to call
__endio_write_update_ordered in case of an error.

This patch removes last use of struct buffer_head from btrfs.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: add Kconfig dependency for BLAKE2B

Because the BLAKE2B code went through a different tree, it was not
available at the time the btrfs part was merged. Now that the Kconfig
symbol exists, add

btrfs: add Kconfig dependency for BLAKE2B

Because the BLAKE2B code went through a different tree, it was not
available at the time the btrfs part was merged. Now that the Kconfig
symbol exists, add it to the list.

Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: add sha256 to checksumming algorithm

Add sha256 to the list of possible checksumming algorithms used by BTRFS.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterb

btrfs: add sha256 to checksumming algorithm

Add sha256 to the list of possible checksumming algorithms used by BTRFS.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: add xxhash64 to checksumming algorithms

Add xxhash64 to the list of possible checksumming algorithms used by
BTRFS.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David

btrfs: add xxhash64 to checksumming algorithms

Add xxhash64 to the list of possible checksumming algorithms used by
BTRFS.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: Fix build error while LIBCRC32C is module

If CONFIG_BTRFS_FS is y and CONFIG_LIBCRC32C is m,
building fails:

fs/btrfs/super.o: In function `btrfs_mount_root':
super.c:(.text+0xb7f9): und

btrfs: Fix build error while LIBCRC32C is module

If CONFIG_BTRFS_FS is y and CONFIG_LIBCRC32C is m,
building fails:

fs/btrfs/super.o: In function `btrfs_mount_root':
super.c:(.text+0xb7f9): undefined reference to `crc32c_impl'
fs/btrfs/super.o: In function `init_btrfs_fs':
super.c:(.init.text+0x3465): undefined reference to `crc32c_impl'
fs/btrfs/extent-tree.o: In function `hash_extent_data_ref':
extent-tree.c:(.text+0xe60): undefined reference to `crc32c'
extent-tree.c:(.text+0xe78): undefined reference to `crc32c'
extent-tree.c:(.text+0xe8b): undefined reference to `crc32c'
fs/btrfs/dir-item.o: In function `btrfs_insert_xattr_item':
dir-item.c:(.text+0x291): undefined reference to `crc32c'
fs/btrfs/dir-item.o: In function `btrfs_insert_dir_item':
dir-item.c:(.text+0x429): undefined reference to `crc32c'

Select LIBCRC32C to fix it.

Reported-by: Hulk Robot <hulkci@huawei.com>
Fixes: d5178578bcd4 ("btrfs: directly call into crypto framework for checksumming")
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: directly call into crypto framework for checksumming

Currently btrfs_csum_data() relied on the crc32c() wrapper around the
crypto framework for calculating the CRCs.

As we have our own crypt

btrfs: directly call into crypto framework for checksumming

Currently btrfs_csum_data() relied on the crc32c() wrapper around the
crypto framework for calculating the CRCs.

As we have our own crypto_shash structure in the fs_info now, we can
directly call into the crypto framework without going trough the wrapper.

This way we can even remove the btrfs_csum_data() and btrfs_csum_final()
wrappers.

The module dependency on crc32c is preserved via MODULE_SOFTDEP("pre:
crc32c"), which was previously provided by LIBCRC32C config option doing
the same.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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btrfs: add SPDX header to Kconfig

Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: Remove custom crc32c init code

The custom crc32 init code was introduced in
14a958e678cd ("Btrfs: fix btrfs boot when compiled as built-in") to
enable using btrfs as a built-in. However, late

btrfs: Remove custom crc32c init code

The custom crc32 init code was introduced in
14a958e678cd ("Btrfs: fix btrfs boot when compiled as built-in") to
enable using btrfs as a built-in. However, later as pointed out by
60efa5eb2e88 ("Btrfs: use late_initcall instead of module_init") this
wasn't enough and finally btrfs was switched to late_initcall which
comes after the generic crc32c implementation is initiliased. The
latter commit superseeded the former. Now that we don't have to
maintain our own code let's just remove it and switch to using the
generic implementation.

Despite touching a lot of files the patch is really simple. Here is the gist of
the changes:

1. Select LIBCRC32C rather than the low-level modules.
2. s/btrfs_crc32c/crc32c/g
3. replace hash.h with linux/crc32c.h
4. Move the btrfs namehash funcs to ctree.h and change the tree accordingly.

I've tested this with btrfs being both a module and a built-in and xfstest
doesn't complain.

Does seem to fix the longstanding problem of not automatically selectiong
the crc32c module when btrfs is used. Possibly there is a workaround in
dracut.

The modinfo confirms that now all the module dependencies are there:

before:
depends: zstd_compress,zstd_decompress,raid6_pq,xor,zlib_deflate

after:
depends: libcrc32c,zstd_compress,zstd_decompress,raid6_pq,xor,zlib_deflate

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add more info to changelog from mails ]
Signed-off-by: David Sterba <dsterba@suse.com>

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fs/*/Kconfig: drop links to 404-compliant http://acl.bestbits.at

This link is replicated in most filesystems' config stanzas. Referring
to an archived version of that site is pointless as it mostly

fs/*/Kconfig: drop links to 404-compliant http://acl.bestbits.at

This link is replicated in most filesystems' config stanzas. Referring
to an archived version of that site is pointless as it mostly deals with
patches; user documentation is available elsewhere.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Acked-by: David Sterba <dsterba@suse.com>
Acked-by: "Yan, Zheng" <zyan@redhat.com>
Acked-by: Chao Yu <yuchao0@huawei.com>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Acked-by: Steve French <smfrench@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

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Btrfs: add a extent ref verify tool

We were having corruption issues that were tied back to problems with
the extent tree. In order to track them down I built this tool to try
and find the culprit,

Btrfs: add a extent ref verify tool

We were having corruption issues that were tied back to problems with
the extent tree. In order to track them down I built this tool to try
and find the culprit, which was pretty successful. If you compile with
this tool on it will live verify every ref update that the fs makes and
make sure it is consistent and valid. I've run this through with
xfstests and haven't gotten any false positives. Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update error messages, add fixup from Dan Carpenter to handle errors
of read_tree_block ]
Signed-off-by: David Sterba <dsterba@suse.com>

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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

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>

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rcu: Make SRCU optional by using CONFIG_SRCU

SRCU is not necessary to be compiled by default in all cases. For tinification
efforts not compiling SRCU unless necessary is desirable.

The current pat

rcu: Make SRCU optional by using CONFIG_SRCU

SRCU is not necessary to be compiled by default in all cases. For tinification
efforts not compiling SRCU unless necessary is desirable.

The current patch tries to make compiling SRCU optional by introducing a new
Kconfig option CONFIG_SRCU which is selected when any of the components making
use of SRCU are selected.

If we do not select CONFIG_SRCU, srcu.o will not be compiled at all.

text data bss dec hex filename
2007 0 0 2007 7d7 kernel/rcu/srcu.o

Size of arch/powerpc/boot/zImage changes from

text data bss dec hex filename
831552 64180 23944 919676 e087c arch/powerpc/boot/zImage : before
829504 64180 23952 917636 e0084 arch/powerpc/boot/zImage : after

so the savings are about ~2000 bytes.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ]

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Btrfs: fix btrfs boot when compiled as built-in

After the change titled "Btrfs: add support for inode properties", if
btrfs was built-in the kernel (i.e. not as a module), it would cause a
kernel pa

Btrfs: fix btrfs boot when compiled as built-in

After the change titled "Btrfs: add support for inode properties", if
btrfs was built-in the kernel (i.e. not as a module), it would cause a
kernel panic, as reported recently by Fengguang:

[ 2.024722] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 2.027814] IP: [<ffffffff81501594>] crc32c+0xc/0x6b
[ 2.028684] PGD 0
[ 2.028684] Oops: 0000 [#1] SMP
[ 2.028684] Modules linked in:
[ 2.028684] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc7-04795-ga7b57c2 #1
[ 2.028684] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 2.028684] task: ffff88000edba100 ti: ffff88000edd6000 task.ti: ffff88000edd6000
[ 2.028684] RIP: 0010:[<ffffffff81501594>] [<ffffffff81501594>] crc32c+0xc/0x6b
[ 2.028684] RSP: 0000:ffff88000edd7e58 EFLAGS: 00010246
[ 2.028684] RAX: 0000000000000000 RBX: ffffffff82295550 RCX: 0000000000000000
[ 2.028684] RDX: 0000000000000011 RSI: ffffffff81efe393 RDI: 00000000fffffffe
[ 2.028684] RBP: ffff88000edd7e60 R08: 0000000000000003 R09: 0000000000015d20
[ 2.028684] R10: ffffffff81ef225e R11: ffffffff811b0222 R12: ffffffffffffffff
[ 2.028684] R13: 0000000000000239 R14: 0000000000000000 R15: 0000000000000000
[ 2.028684] FS: 0000000000000000(0000) GS:ffff88000fa00000(0000) knlGS:0000000000000000
[ 2.028684] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 2.028684] CR2: 0000000000000000 CR3: 000000000220c000 CR4: 00000000000006f0
[ 2.028684] Stack:
[ 2.028684] ffffffff82295550 ffff88000edd7e80 ffffffff8238af62 ffffffff8238ac05
[ 2.028684] 0000000000000000 ffff88000edd7e98 ffffffff8238ac0f ffffffff8238ac05
[ 2.028684] ffff88000edd7f08 ffffffff810002ba ffff88000edd7f00 ffffffff810e2404
[ 2.028684] Call Trace:
[ 2.028684] [<ffffffff8238af62>] btrfs_props_init+0x4f/0x96
[ 2.028684] [<ffffffff8238ac05>] ? ftrace_define_fields_btrfs_space_reservation+0x145/0x145
[ 2.028684] [<ffffffff8238ac0f>] init_btrfs_fs+0xa/0xf0
[ 2.028684] [<ffffffff8238ac05>] ? ftrace_define_fields_btrfs_space_reservation+0x145/0x145
[ 2.028684] [<ffffffff810002ba>] do_one_initcall+0xa4/0x13a
[ 2.028684] [<ffffffff810e2404>] ? parse_args+0x25f/0x33d
[ 2.028684] [<ffffffff8234cf75>] kernel_init_freeable+0x1aa/0x230
[ 2.028684] [<ffffffff8234c785>] ? do_early_param+0x88/0x88
[ 2.028684] [<ffffffff819f61b5>] ? rest_init+0x89/0x89
[ 2.028684] [<ffffffff819f61c3>] kernel_init+0xe/0x109

The issue here is that the initialization function of btrfs (super.c:init_btrfs_fs)
started using crc32c (from lib/libcrc32c.c). But when it needs to call crc32c (as
part of the properties initialization routine), the libcrc32c is not yet initialized,
so crc32c derreferenced a NULL pointer (lib/libcrc32c.c:tfm), causing the kernel
panic on boot.

The approach to fix this is to use crypto component directly to use its crc32c (which
is basically what lib/libcrc32c.c is, a wrapper around crypto). This is what ext4 is
doing as well, it uses crypto directly to get crc32c functionality.

Verified this works both when btrfs is built-in and when it's loadable kernel module.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>

show more ...

btrfs: update kconfig help text

Reflect the current status. Portions of the text taken from the
wiki pages.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fus

btrfs: update kconfig help text

Reflect the current status. Portions of the text taken from the
wiki pages.

Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

show more ...

Docs: Kconfig: `devlopers' -> `developers'

Signed-off-by: Michael Witten <mfwitten@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Btrfs: add support for asserts

One of the complaints we get a lot is how many BUG_ON()'s we have. So to help
with this I'm introducing a kconfig option to enable/disable a new ASSERT()
mechanism mu

Btrfs: add support for asserts

One of the complaints we get a lot is how many BUG_ON()'s we have. So to help
with this I'm introducing a kconfig option to enable/disable a new ASSERT()
mechanism much like what XFS does. This will allow us developers to still get
our nice panics but allow users/distros to compile them out. With this we can
go through and convert any BUG_ON()'s that we have to catch actual programming
mistakes to the new ASSERT() and then fix everybody else to return errors. This
will also allow developers to leave sanity checks in their new code to make sure
we don't trip over problems while testing stuff and vetting new features.
Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

show more ...