[Cluster-devel] [GFS2 PATCH 3/4] gfs2: add new function gfs2_inpl_rsrv_ret_max_avl

[Steven Whitehouse <swhiteho@redhat.com>]

Hi,

Likewise here, if the available blocks was added to the allocation 
parms, then this would help to neaten up the code a bit. Otherwise all 
four patches look good to me,

Steve.

On 12/02/15 16:54, Abhi Das wrote:
> This is a variant of the existing gfs2_inplace_reserve() function.
>
> If the requested number of blocks are not available to be reserved
> from any of the rgrps, gfs2_inplace_reserve() return -ENOSPC.
> gfs2_inpl_rsrv_ret_max_val() will also return the maximum blocks
> available in an extra parameter 'max_avail'.
>
> If acceptable to the caller logic, either of these inplace resreve
> functions may be called again requesting 'max_avail' blocks to
> avoid the -ENOSPC error.
>
> Signed-off-by: Abhi Das <adas@redhat.com>
> ---
>   fs/gfs2/rgrp.c | 13 +++++++++++--
>   fs/gfs2/rgrp.h | 10 +++++++++-
>   2 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
> index 9150207..0fa9ae3 100644
> --- a/fs/gfs2/rgrp.c
> +++ b/fs/gfs2/rgrp.c
> @@ -1942,14 +1942,17 @@ static inline int fast_to_acquire(struct gfs2_rgrpd *rgd)
>   }
>   
>   /**
> - * gfs2_inplace_reserve - Reserve space in the filesystem
> + * gfs2_inpl_rsrv_ret_max_avl - Reserve space in the filesystem
>    * @ip: the inode to reserve space for
>    * @ap: the allocation parameters
> + * @max_avail: If non-NULL, return the max available extent if -ENOSPC
>    *
>    * Returns: errno
>    */
>   
> -int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *ap)
> +int gfs2_inpl_rsrv_ret_max_avl(struct gfs2_inode *ip,
> +			       const struct gfs2_alloc_parms *ap,
> +			       u32 *max_avail)
>   {
>   	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
>   	struct gfs2_rgrpd *begin = NULL;
> @@ -1958,6 +1961,7 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *a
>   	u64 last_unlinked = NO_BLOCK;
>   	int loops = 0;
>   	u32 skip = 0;
> +	u32 max_avlbl = 0;
>   
>   	if (sdp->sd_args.ar_rgrplvb)
>   		flags |= GL_SKIP;
> @@ -2030,6 +2034,8 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *a
>   		if (rs->rs_rbm.rgd->rd_free_clone >= ap->target) {
>   			ip->i_rgd = rs->rs_rbm.rgd;
>   			return 0;
> +		} else if (rs->rs_rbm.rgd->rd_free_clone > max_avlbl) {
> +			max_avlbl = rs->rs_rbm.rgd->rd_free_clone;
>   		}
>   
>   check_rgrp:
> @@ -2068,6 +2074,9 @@ next_rgrp:
>   			gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
>   	}
>   
> +	if (max_avail)
> +		*max_avail = max_avlbl;
> +
>   	return -ENOSPC;
>   }
>   
> diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h
> index b104f4a..2adffca 100644
> --- a/fs/gfs2/rgrp.h
> +++ b/fs/gfs2/rgrp.h
> @@ -41,7 +41,15 @@ extern void gfs2_rgrp_go_unlock(struct gfs2_holder *gh);
>   extern struct gfs2_alloc *gfs2_alloc_get(struct gfs2_inode *ip);
>   
>   #define GFS2_AF_ORLOV 1
> -extern int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *ap);
> +extern int gfs2_inpl_rsrv_ret_max_avl(struct gfs2_inode *ip,
> +				      const struct gfs2_alloc_parms *ap,
> +				      u32 *max_avail);
> +static inline int gfs2_inplace_reserve(struct gfs2_inode *ip,
> +				       const struct gfs2_alloc_parms *ap)
> +{
> +	return gfs2_inpl_rsrv_ret_max_avl(ip, ap, NULL);
> +}
> +
>   extern void gfs2_inplace_release(struct gfs2_inode *ip);
>   
>   extern int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *n,