Re: [v2] ceph: support getting ceph.dir.rsnaps vxattr

[Jeff Layton <jlayton@kernel.org>]

On Fri, 2020-08-28 at 09:28 +0800, Yanhu Cao wrote:
> It's easy to know how many snapshots have been created.
> 
> Link: https://tracker.ceph.com/issues/47168
> Signed-off-by: Yanhu Cao <gmayyyha@gmail.com>
> ---
>  fs/ceph/inode.c      | 1 +
>  fs/ceph/mds_client.c | 9 ++++++++-
>  fs/ceph/mds_client.h | 1 +
>  fs/ceph/super.h      | 2 +-
>  fs/ceph/xattr.c      | 7 +++++++
>  5 files changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 357c937699d5..650cad4b3ecb 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -891,6 +891,7 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
>  			ci->i_rfiles = le64_to_cpu(info->rfiles);
>  			ci->i_rsubdirs = le64_to_cpu(info->rsubdirs);
>  			ci->i_dir_pin = iinfo->dir_pin;
> +			ci->i_rsnaps = iinfo->rsnaps;
>  			ceph_decode_timespec64(&ci->i_rctime, &info->rctime);
>  		}
>  	}
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 4a26862d7667..3466845c0179 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -176,6 +176,13 @@ static int parse_reply_info_in(void **p, void *end,
>  			memset(&info->snap_btime, 0, sizeof(info->snap_btime));
>  		}
>  
> +		/* snapshot count, remains zero for v<=3 */
> +		if (struct_v >= 4) {
> +			ceph_decode_64_safe(p, end, info->rsnaps, bad);
> +		} else {
> +			info->rsnaps = 0;
> +		}
> +
>  		*p = end;
>  	} else {
>  		if (features & CEPH_FEATURE_MDS_INLINE_DATA) {
> @@ -214,7 +221,7 @@ static int parse_reply_info_in(void **p, void *end,
>  		}
>  
>  		info->dir_pin = -ENODATA;
> -		/* info->snap_btime remains zero */
> +		/* info->snap_btime and info->rsnaps remain zero */
>  	}
>  	return 0;
>  bad:
> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> index bc9e95937d7c..76f2ed1a7cbf 100644
> --- a/fs/ceph/mds_client.h
> +++ b/fs/ceph/mds_client.h
> @@ -88,6 +88,7 @@ struct ceph_mds_reply_info_in {
>  	s32 dir_pin;
>  	struct ceph_timespec btime;
>  	struct ceph_timespec snap_btime;
> +	u64 rsnaps;
>  	u64 change_attr;
>  };
>  
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index 4c3c964b1c54..eb108b69da71 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -332,7 +332,7 @@ struct ceph_inode_info {
>  
>  	/* for dirs */
>  	struct timespec64 i_rctime;
> -	u64 i_rbytes, i_rfiles, i_rsubdirs;
> +	u64 i_rbytes, i_rfiles, i_rsubdirs, i_rsnaps;
>  	u64 i_files, i_subdirs;
>  
>  	/* quotas */
> diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
> index 3a733ac33d9b..c7d8ecc3d04b 100644
> --- a/fs/ceph/xattr.c
> +++ b/fs/ceph/xattr.c
> @@ -231,6 +231,12 @@ static ssize_t ceph_vxattrcb_dir_rsubdirs(struct ceph_inode_info *ci, char *val,
>  	return ceph_fmt_xattr(val, size, "%lld", ci->i_rsubdirs);
>  }
>  
> +static ssize_t ceph_vxattrcb_dir_rsnaps(struct ceph_inode_info *ci, char *val,
> +					  size_t size)
> +{
> +	return ceph_fmt_xattr(val, size, "%lld", ci->i_rsnaps);
> +}
> +
>  static ssize_t ceph_vxattrcb_dir_rbytes(struct ceph_inode_info *ci, char *val,
>  					size_t size)
>  {
> @@ -352,6 +358,7 @@ static struct ceph_vxattr ceph_dir_vxattrs[] = {
>  	XATTR_RSTAT_FIELD(dir, rentries),
>  	XATTR_RSTAT_FIELD(dir, rfiles),
>  	XATTR_RSTAT_FIELD(dir, rsubdirs),
> +	XATTR_RSTAT_FIELD(dir, rsnaps),
>  	XATTR_RSTAT_FIELD(dir, rbytes),
>  	XATTR_RSTAT_FIELD(dir, rctime),
>  	{

Sorry we missed this one Yanhu. In the future, please put [PATCH] in the
subject line in some fashion and we may spot it more easily.

This looks fine to me -- merged into ceph-client/testing branch, though
I did revise the changelog to be a bit more descriptive. Tell me if you
think it needs changes.

Thanks!
-- 
Jeff Layton <jlayton@kernel.org>