On 24.11.2017 06:10, Qu Wenruo wrote:
> Since block I/O is always done in unit of 512 bytes, add BI_SECTOR_SIZE
> and BI_SECTOR_SHIFT macros and to_sector() and to_bytes() for later
> use.
>
> Although the best position to define such things should be bvec.h, and
> to_sector() to_bytes() are also defined in device-mapper.h, there are
> a lot of code defining their own SECTOR_SIZE and to_bytes() in
> device-mapper is not using u64 (unsigned long long) but unsigned long,
> which doesn't fit btrfs usage.
>
> So define btrfs' own macros and inlined converters.
>
> Signed-off-by: Qu Wenruo <w...@suse.com>
> ---
> fs/btrfs/ctree.h | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 8fc690384c58..8f6f57167661 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -3734,4 +3734,17 @@ static inline int btrfs_is_testing(struct
> btrfs_fs_info *fs_info)
> #endif
> return 0;
> }
> +
> +#define BI_SECTOR_SHIFT (9)
> +#define BI_SECTOR_SIZE (1 << BI_SECTOR_SHIFT)
> +
> +static inline u64 to_bytes(sector_t n)
> +{
> + return ((u64)n << BI_SECTOR_SHIFT);
> +}
> +
> +static inline sector_t to_sector(u64 n)
> +{
> + return (n >> BI_SECTOR_SHIFT);
> +}
nit: I don't like the naming, I'd rather have something similar to what
xfs has for its conversion macros i.e:
XFS_FSS_TO_BB - filesystem sector to basic block (bb in this case is 512
bytes)
so why not - BTRFS_B_TO_BB or BTRFS_B_TO_S and BTRFS_S_TO_B. Or
something like that but just to_bytes and to_sector look a bit silly.
It's not a big paint point but more of a "let's get the good ideas from
other fsses"
> #endif
>
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