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| author | Miguel <miguel.filipe@gmail.com> | 2008-04-11 21:45:51 +0200 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2008-09-25 17:04:01 +0200 |
| commit | a5eb62e345fc1818d0d8b6181463200a9e8dfe39 (patch) | |
| tree | 2e67b0628c8312d941f52edadc6c49bd8ac4c914 /fs/btrfs/crc32c.h | |
| parent | Btrfs: Fixup a few u64<->pointer casts for 32 bit (diff) | |
| download | linux-a5eb62e345fc1818d0d8b6181463200a9e8dfe39.tar.xz linux-a5eb62e345fc1818d0d8b6181463200a9e8dfe39.zip | |
Btrfs: Endianess bug fix for v0.13 with kernels
Fix for a endianess BUG when using btrfs v0.13 with kernels older than 2.6.23
Problem:
Has of v0.13, btrfs-progs is using crc32c.c equivalent to the one found on
linux-2.6.23/lib/libcrc32c.c Since crc32c_le() changed in linux-2.6.23, when
running btrfs v0.13 with older kernels we have a missmatch between the versions
of crc32c_le() from btrfs-progs and libcrc32c in the kernel. This missmatch
causes a bug when using btrfs on big endian machines.
Solution:
btrfs_crc32c() macro that when compiling for kernels older than 2.6.23, does
endianess conversion to parameters and return value of crc32c().
This endianess conversion nullifies the differences in implementation
of crc32c_le().
If kernel 2.6.23 or better, it calls crc32c().
Signed-off-by: Miguel Sousa Filipe <miguel.filipe@gmail.com>
---
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/crc32c.h')
| -rw-r--r-- | fs/btrfs/crc32c.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/fs/btrfs/crc32c.h b/fs/btrfs/crc32c.h new file mode 100644 index 000000000000..a93255b4ee27 --- /dev/null +++ b/fs/btrfs/crc32c.h @@ -0,0 +1,17 @@ +#include <asm/byteorder.h> +#include <linux/crc32c.h> +#include <linux/version.h> + +/** + * implementation of crc32c_le() changed in linux-2.6.23, + * has of v0.13 btrfs-progs is using the latest version. + * We must workaround older implementations of crc32c_le() + * found on older kernel versions. + */ +#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23) +#define btrfs_crc32c(seed, data, length) \ + __cpu_to_le32( crc32c( __le32_to_cpu(seed), data, length) ) +#else +#define btrfs_crc32c(seed, data, length) \ + crc32c(seed, data, length) +#endif |