From: Mike Christie <[email protected]> This patch adds helpers to encode/decode the starting blocks locking code. They are the equivalent of ENCODE_START and DECODE_START_LEGACY_COMPAT_LEN in the userspace ceph code.
Signed-off-by: Mike Christie <[email protected]> --- include/linux/ceph/decode.h | 55 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/include/linux/ceph/decode.h b/include/linux/ceph/decode.h index a6ef9cc..96ec43d 100644 --- a/include/linux/ceph/decode.h +++ b/include/linux/ceph/decode.h @@ -217,6 +217,61 @@ static inline void ceph_encode_string(void **p, void *end, *p += len; } +/* + * version and length starting block encoders/decoders + */ + +/* current code version (u8) + compat code version (u8) + len of struct (u32) */ +#define CEPH_ENCODING_START_BLK_LEN 6 + +/** + * ceph_start_encoding - start encoding block + * @p: buffer to encode data in + * @curr_ver: current (code) version of the encoding + * @compat_ver: oldest code version that can decode it + * @len: length of data that will be encoded in buffer + */ +static inline void ceph_start_encoding(void **p, u8 curr_ver, u8 compat_ver, + u32 len) +{ + ceph_encode_8(p, curr_ver); + ceph_encode_8(p, compat_ver); + ceph_encode_32(p, len); +} + +/** + * ceph_start_decoding_compat - decode block with legacy support for older schemes + * @p: buffer to decode + * @end: end of decode buffer + * @curr_ver: current version of the encoding that the code supports/encode + * @compat_ver: oldest version that includes a __u8 compat version field + * @len_ver: oldest version that includes a __u32 length wrapper + * @len: buffer to return len of data in buffer + */ +static inline int ceph_start_decoding_compat(void **p, void *end, u8 curr_ver, + u8 compat_ver, u8 len_ver, u32 *len) +{ + u8 struct_ver, struct_compat; + + ceph_decode_8_safe(p, end, struct_ver, fail); + if (struct_ver >= curr_ver) { + ceph_decode_8_safe(p, end, struct_compat, fail); + if (curr_ver < struct_compat) + return -EINVAL; + } + + if (struct_ver >= len_ver) { + ceph_decode_32_safe(p, end, *len, fail); + } else { + *len = 0; + } + + return 0; +fail: + return -ERANGE; +} + + #define ceph_encode_need(p, end, n, bad) \ do { \ if (!likely(ceph_has_room(p, end, n))) \ -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
