On 17.05.2018 09:27, Qu Wenruo wrote:
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Overall it looks good and useful just a couple of nits below.
> ---
> fs/btrfs/lzo.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
> index 0667ea07f766..3d2ae4c08876 100644
> --- a/fs/btrfs/lzo.c
> +++ b/fs/btrfs/lzo.c
> @@ -17,6 +17,29 @@
>
> #define LZO_LEN 4
>
> +/*
> + * Btrfs LZO compression format
> + *
> + * Regular LZO compressed data extent is consist of:
nit: s/is consist/consists
> + * 1. Header
> + * Fixed size. LZO_LEN (4) bytes long, LE16.
> + * Records the total size (*includes* the header) of real compressed data.
> + *
> + * 2. Segment(s)
> + * Variable size. Includes one segment header, and then data payload.
> + * One btrfs compressed data can have one or more segments.
So "one btrfs compressed data" should really mean "one btrfs compressed
extent" I guess?
> + *
> + * 2.1 Segment header
> + * Fixed size. LZO_LEN (4) bytes long, LE16.
> + * Records the total size of the segment (*excludes* the header).
> + *
> + * 2.2 Data Payload
> + * Variable size. Size up limit should be lzo1x_worst_compress(PAGE_SIZE).
> + *
> + * While for inlined LZO compressed data extent, it doesn't have Header, just
> + * one Segment.
> + */
> +
> struct workspace {
> void *mem;
> void *buf; /* where decompressed data goes */
>
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