Signed-off-by: Qu Wenruo <w...@suse.com> --- 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: + * 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. + * + * 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 */ -- 2.17.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html