linux/fs/btrfs/Kconfig

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config BTRFS_FS
tristate "Btrfs filesystem support"
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>
2014-01-12 03:22:46 +01:00
select CRYPTO
select CRYPTO_CRC32C
select ZLIB_INFLATE
select ZLIB_DEFLATE
select LZO_COMPRESS
select LZO_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.
To learn more about Access Control Lists, visit the POSIX ACLs for
Linux website <http://acl.bestbits.at/>.
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.