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authorMiguel <miguel.filipe@gmail.com>2008-04-11 15:45:51 -0400
committerChris Mason <chris.mason@oracle.com>2008-09-25 11:04:01 -0400
commita5eb62e345fc1818d0d8b6181463200a9e8dfe39 (patch)
tree2e67b0628c8312d941f52edadc6c49bd8ac4c914 /fs/btrfs/crc32c.h
parent587f77043a1c86e2a7900ff2ce86bef3c1f4e075 (diff)
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.h17
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 @@
1#include <asm/byteorder.h>
2#include <linux/crc32c.h>
3#include <linux/version.h>
4
5/**
6 * implementation of crc32c_le() changed in linux-2.6.23,
7 * has of v0.13 btrfs-progs is using the latest version.
8 * We must workaround older implementations of crc32c_le()
9 * found on older kernel versions.
10 */
11#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
12#define btrfs_crc32c(seed, data, length) \
13 __cpu_to_le32( crc32c( __le32_to_cpu(seed), data, length) )
14#else
15#define btrfs_crc32c(seed, data, length) \
16 crc32c(seed, data, length)
17#endif