14a958e678
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>
91 lines
2.9 KiB
Plaintext
91 lines
2.9 KiB
Plaintext
config BTRFS_FS
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tristate "Btrfs filesystem support"
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select CRYPTO
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select CRYPTO_CRC32C
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select ZLIB_INFLATE
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select ZLIB_DEFLATE
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select LZO_COMPRESS
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select LZO_DECOMPRESS
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select RAID6_PQ
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select XOR_BLOCKS
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help
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Btrfs is a general purpose copy-on-write filesystem with extents,
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writable snapshotting, support for multiple devices and many more
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features focused on fault tolerance, repair and easy administration.
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The filesystem disk format is no longer unstable, and it's not
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expected to change unless there are strong reasons to do so. If there
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is a format change, file systems with a unchanged format will
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continue to be mountable and usable by newer kernels.
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For more information, please see the web pages at
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http://btrfs.wiki.kernel.org.
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To compile this file system support as a module, choose M here. The
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module will be called btrfs.
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If unsure, say N.
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config BTRFS_FS_POSIX_ACL
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bool "Btrfs POSIX Access Control Lists"
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depends on BTRFS_FS
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select FS_POSIX_ACL
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help
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POSIX Access Control Lists (ACLs) support permissions for users and
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groups beyond the owner/group/world scheme.
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To learn more about Access Control Lists, visit the POSIX ACLs for
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Linux website <http://acl.bestbits.at/>.
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If you don't know what Access Control Lists are, say N
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config BTRFS_FS_CHECK_INTEGRITY
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bool "Btrfs with integrity check tool compiled in (DANGEROUS)"
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depends on BTRFS_FS
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help
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Adds code that examines all block write requests (including
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writes of the super block). The goal is to verify that the
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state of the filesystem on disk is always consistent, i.e.,
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after a power-loss or kernel panic event the filesystem is
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in a consistent state.
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If the integrity check tool is included and activated in
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the mount options, plenty of kernel memory is used, and
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plenty of additional CPU cycles are spent. Enabling this
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functionality is not intended for normal use.
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In most cases, unless you are a btrfs developer who needs
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to verify the integrity of (super)-block write requests
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during the run of a regression test, say N
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config BTRFS_FS_RUN_SANITY_TESTS
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bool "Btrfs will run sanity tests upon loading"
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depends on BTRFS_FS
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help
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This will run some basic sanity tests on the free space cache
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code to make sure it is acting as it should. These are mostly
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regression tests and are only really interesting to btrfs
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developers.
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If unsure, say N.
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config BTRFS_DEBUG
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bool "Btrfs debugging support"
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depends on BTRFS_FS
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help
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Enable run-time debugging support for the btrfs filesystem. This may
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enable additional and expensive checks with negative impact on
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performance, or export extra information via sysfs.
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If unsure, say N.
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config BTRFS_ASSERT
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bool "Btrfs assert support"
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depends on BTRFS_FS
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help
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Enable run-time assertion checking. This will result in panics if
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any of the assertions trip. This is meant for btrfs developers only.
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If unsure, say N.
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