On Tue, Dec 06, 2011 at 05:13:51PM -0700, Andreas Dilger wrote:
> Reserve the EXT4_FEATURE_INCOMPAT_INLINEDATA feature flag for use
> with storing small file data in the i_blocks field (up to 60 bytes)
> and/or the large xattr space (after i_extra_isize, up to the large
> inode size). On typical filesystems this can save 1-3% of the space,
> and more importantly it also avoids seeking to read the data block.
>
> This will become increasingly important with bigalloc filesystems,
> since they consume a full cluster of blocks for each file, including
> small directories that could easily fit into the inode itself.
>
> Signed-off-by: Andreas Dilger <adilger@xxxxxxxxxxxxx>
> Originally-by: Tao Ma <tm@xxxxxx>
> ---
> lib/ext2fs/ext2_fs.h | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
> index 0f8cde8..6cf47f9 100644
> --- a/lib/ext2fs/ext2_fs.h
> +++ b/lib/ext2fs/ext2_fs.h
> @@ -719,6 +719,7 @@ struct ext2_super_block {
> #define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
> #define EXT4_FEATURE_INCOMPAT_EA_INODE 0x0400
> #define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000
> +#define EXT4_FEATURE_INCOMPAT_INLINEDATA 0x2000 /* data in inode */
I was using 0x2000 for EXT4_FEATURE_INCOMPAT_BG_USE_META_CSUM, to change the
block group checksum to use crc32c.
--D
>
> #define EXT2_FEATURE_COMPAT_SUPP 0
> #define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
> --
> 1.7.2
>
>
>
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