Re: [PATCH 3/5] zfs com.delphix:hole_birth feature support

[Andrei Borzenkov <arvidjaar@gmail.com>]

В Thu, 16 Apr 2015 08:22:08 +0300
Toomas Soome <tsoome@me.com> пишет:

This really needs better explanation. Otherwise this looks like either
old code was broken to start with and it is a bug fix or new code needs
some conditionals on new feature.

> 
> ---
>  grub-core/fs/zfs/zfs.c |    6 ++++--
>  include/grub/zfs/spa.h |    4 +++-
>  2 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/grub-core/fs/zfs/zfs.c b/grub-core/fs/zfs/zfs.c
> index 2689986..a731c3d 100644
> --- a/grub-core/fs/zfs/zfs.c
> +++ b/grub-core/fs/zfs/zfs.c
> @@ -280,7 +280,9 @@ grub_crypto_cipher_handle_t (*grub_zfs_load_key) (const struct grub_zfs_key *key
>   */
>  #define MAX_SUPPORTED_FEATURE_STRLEN 50
>  static const char *spa_feature_names[] = {
> -  "org.illumos:lz4_compress",NULL
> +  "org.illumos:lz4_compress",
> +  "com.delphix:hole_birth",
> +  NULL
>  };
>  
>  static int
> @@ -1751,7 +1753,7 @@ zio_read_gang (blkptr_t * bp, grub_zfs_endian_t endian, dva_t * dva, void *buf,
>  
>    for (i = 0; i < SPA_GBH_NBLKPTRS; i++)
>      {
> -      if (zio_gb->zg_blkptr[i].blk_birth == 0)
> +      if (BP_IS_HOLE(&zio_gb->zg_blkptr[i]))
>  	continue;
>  
>        err = zio_read_data (&zio_gb->zg_blkptr[i], endian, buf, data);
> diff --git a/include/grub/zfs/spa.h b/include/grub/zfs/spa.h
> index 7edb8ab..df43b6b 100644
> --- a/include/grub/zfs/spa.h
> +++ b/include/grub/zfs/spa.h
> @@ -279,7 +279,9 @@ typedef struct blkptr {
>  
>  #define	BP_IDENTITY(bp)		(&(bp)->blk_dva[0])
>  #define	BP_IS_GANG(bp)		DVA_GET_GANG(BP_IDENTITY(bp))
> -#define	BP_IS_HOLE(bp)		((bp)->blk_birth == 0)
> +#define	DVA_IS_EMPTY(dva)	((dva)->dva_word[0] == 0ULL && \
> +				(dva)->dva_word[1] == 0ULL)
> +#define	BP_IS_HOLE(bp)		DVA_IS_EMPTY(BP_IDENTITY(bp))
>  
>  /* BP_IS_RAIDZ(bp) assumes no block compression */
>  #define	BP_IS_RAIDZ(bp)		(DVA_GET_ASIZE(&(bp)->blk_dva[0]) > \