[Virtio-fs] [PATCH 2/3] fuse: Move new mapping setup code in a function

[Liu Bo]

On Wed, Jul 24, 2019 at 05:07:20PM -0400, Vivek Goyal wrote:
> Move new mapping setup code in a separate function. More code will come
> in fuse_iomap_begin() and its becoming too big.

Reviewed-by: Liu Bo <bo.liu at linux.alibaba.com>

thanks,
-liubo
> 
> Signed-off-by: Vivek Goyal <vgoyal at redhat.com>
> ---
>  fs/fuse/file.c | 116 +++++++++++++++++++++++++++----------------------
>  1 file changed, 64 insertions(+), 52 deletions(-)
> 
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index 93f8e62e2b5b..a2c19e4a28b5 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -1882,6 +1882,67 @@ static void fuse_fill_iomap(struct inode *inode, loff_t pos, loff_t length,
>  	}
>  }
>  
> +static int iomap_begin_setup_new_mapping(struct inode *inode, loff_t pos,
> +					 loff_t length, unsigned flags,
> +					 struct iomap *iomap)
> +{
> +	struct fuse_inode *fi = get_fuse_inode(inode);
> +	struct fuse_conn *fc = get_fuse_conn(inode);
> +	struct fuse_dax_mapping *dmap, *alloc_dmap = NULL;
> +	int ret;
> +
> +	/* Can't do reclaim in fault path yet due to lock ordering.
> +	 * Read path takes shared inode lock and that's not sufficient
> +	 * for inline range reclaim. Caller needs to drop lock, wait
> +	 * and retry.
> +	 */
> +	if (flags & IOMAP_FAULT || !(flags & IOMAP_WRITE)) {
> +		alloc_dmap = alloc_dax_mapping(fc);
> +		if (!alloc_dmap)
> +			return -ENOSPC;
> +	} else {
> +		alloc_dmap = alloc_dax_mapping_reclaim(fc, inode);
> +		if (IS_ERR(alloc_dmap))
> +			return PTR_ERR(alloc_dmap);
> +	}
> +
> +	/* If we are here, we should have memory allocated */
> +	if (WARN_ON(!alloc_dmap))
> +		return -EBUSY;
> +
> +	/*
> +	 * Drop read lock and take write lock so that only one
> +	 * caller can try to setup mapping and other waits
> +	 */
> +	down_write(&fi->i_dmap_sem);
> +	/*
> +	 * We dropped lock. Check again if somebody else setup
> +	 * mapping already.
> +	 */
> +	dmap = fuse_dax_interval_tree_iter_first(&fi->dmap_tree, pos,
> +						pos);
> +	if (dmap) {
> +		fuse_fill_iomap(inode, pos, length, iomap, dmap, flags);
> +		dmap_add_to_free_pool(fc, alloc_dmap);
> +		up_write(&fi->i_dmap_sem);
> +		return 0;
> +	}
> +
> +	/* Setup one mapping */
> +	ret = fuse_setup_one_mapping(inode,
> +		ALIGN_DOWN(pos, FUSE_DAX_MEM_RANGE_SZ), alloc_dmap);
> +	if (ret < 0) {
> +		printk("fuse_setup_one_mapping() failed. err=%d"
> +			" pos=0x%llx\n", ret, pos);
> +		dmap_add_to_free_pool(fc, alloc_dmap);
> +		up_write(&fi->i_dmap_sem);
> +		return ret;
> +	}
> +	fuse_fill_iomap(inode, pos, length, iomap, alloc_dmap, flags);
> +	up_write(&fi->i_dmap_sem);
> +	return 0;
> +}
> +
>  /* This is just for DAX and the mapping is ephemeral, do not use it for other
>   * purposes since there is no block device with a permanent mapping.
>   */
> @@ -1890,8 +1951,7 @@ static int fuse_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
>  {
>  	struct fuse_inode *fi = get_fuse_inode(inode);
>  	struct fuse_conn *fc = get_fuse_conn(inode);
> -	struct fuse_dax_mapping *dmap, *alloc_dmap = NULL;
> -	int ret;
> +	struct fuse_dax_mapping *dmap;
>  
>  	/* We don't support FIEMAP */
>  	BUG_ON(flags & IOMAP_REPORT);
> @@ -1932,56 +1992,8 @@ static int fuse_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
>  		if (pos >= i_size_read(inode))
>  			goto iomap_hole;
>  
> -		/* Can't do reclaim in fault path yet due to lock ordering.
> -		 * Read path takes shared inode lock and that's not sufficient
> -		 * for inline range reclaim. Caller needs to drop lock, wait
> -		 * and retry.
> -		 */
> -		if (flags & IOMAP_FAULT || !(flags & IOMAP_WRITE)) {
> -			alloc_dmap = alloc_dax_mapping(fc);
> -			if (!alloc_dmap)
> -				return -ENOSPC;
> -		} else {
> -			alloc_dmap = alloc_dax_mapping_reclaim(fc, inode);
> -			if (IS_ERR(alloc_dmap))
> -				return PTR_ERR(alloc_dmap);
> -		}
> -
> -		/* If we are here, we should have memory allocated */
> -		if (WARN_ON(!alloc_dmap))
> -			return -EBUSY;
> -
> -		/*
> -		 * Drop read lock and take write lock so that only one
> -		 * caller can try to setup mapping and other waits
> -		 */
> -		down_write(&fi->i_dmap_sem);
> -		/*
> -		 * We dropped lock. Check again if somebody else setup
> -		 * mapping already.
> -		 */
> -		dmap = fuse_dax_interval_tree_iter_first(&fi->dmap_tree, pos,
> -							pos);
> -		if (dmap) {
> -			fuse_fill_iomap(inode, pos, length, iomap, dmap, flags);
> -			dmap_add_to_free_pool(fc, alloc_dmap);
> -			up_write(&fi->i_dmap_sem);
> -			return 0;
> -		}
> -
> -		/* Setup one mapping */
> -		ret = fuse_setup_one_mapping(inode,
> -			ALIGN_DOWN(pos, FUSE_DAX_MEM_RANGE_SZ), alloc_dmap);
> -		if (ret < 0) {
> -			printk("fuse_setup_one_mapping() failed. err=%d"
> -				" pos=0x%llx\n", ret, pos);
> -			dmap_add_to_free_pool(fc, alloc_dmap);
> -			up_write(&fi->i_dmap_sem);
> -			return ret;
> -		}
> -		fuse_fill_iomap(inode, pos, length, iomap, alloc_dmap, flags);
> -		up_write(&fi->i_dmap_sem);
> -		return 0;
> +		return iomap_begin_setup_new_mapping(inode, pos, length, flags,
> +						    iomap);
>  	}
>  
>  	/*
> -- 
> 2.17.2