[pnfs] [PATCH 03/25] pnfs: block: blocklayout stub

[Benny Halevy]

On Feb. 14, 2008, 20:21 +0200, Fred Isaman <iisaman at citi.umich.edu> wrote:
> Adds the minimal structure for a pnfs block layout driver,
> with all function pointers aimed at stubs.
> 
> Signed-off-by: Fred Isaman <iisaman at citi.umich.edu>
> ---
>  fs/nfs/Makefile          |    2 +
>  fs/nfs/nfs4blocklayout.c |  224 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/nfs_fs.h   |    1 +

How about a Kconfig option?
I don't think everybody using pnfs may want the block layout baggage
necessarily (this is actually true also vice versa, i.e. the file
layout probably needs a Kconfig option of its own as well).

>  3 files changed, 227 insertions(+), 0 deletions(-)
>  create mode 100644 fs/nfs/nfs4blocklayout.c
> 
> diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
> index 81c8837..be2afdd 100644
> --- a/fs/nfs/Makefile
> +++ b/fs/nfs/Makefile
> @@ -21,3 +21,5 @@ nfs-$(CONFIG_SYSCTL) += sysctl.o
>  
>  obj-m += nfslayoutdriver.o
>  nfslayoutdriver-objs := nfs4filelayout.o nfs4filelayoutdev.o
> +obj-m += blocklayoutdriver.o
> +blocklayoutdriver-objs := nfs4blocklayout.o
> diff --git a/fs/nfs/nfs4blocklayout.c b/fs/nfs/nfs4blocklayout.c
> new file mode 100644
> index 0000000..b23e163
> --- /dev/null
> +++ b/fs/nfs/nfs4blocklayout.c
> @@ -0,0 +1,224 @@
> +/*
> + *  linux/fs/nfs/nfs4blocklayout.c
> + *
> + *  Module for the NFSv4.1 pNFS block layout driver.
> + *
> + *  Copyright (c) 2006 The Regents of the University of Michigan.
> + *  All rights reserved.
> + *
> + *  Andy Adamson <andros at citi.umich.edu>
> + *  Fred Isaman <iisaman at umich.edu>
> + *
> + * permission is granted to use, copy, create derivative works and
> + * redistribute this software and such derivative works for any purpose,
> + * so long as the name of the university of michigan is not used in
> + * any advertising or publicity pertaining to the use or distribution
> + * of this software without specific, written prior authorization.  if
> + * the above copyright notice or any other identification of the
> + * university of michigan is included in any copy of any portion of
> + * this software, then the disclaimer below must also be included.
> + *
> + * this software is provided as is, without representation from the
> + * university of michigan as to its fitness for any purpose, and without
> + * warranty by the university of michigan of any kind, either express
> + * or implied, including without limitation the implied warranties of
> + * merchantability and fitness for a particular purpose.  the regents
> + * of the university of michigan shall not be liable for any damages,
> + * including special, indirect, incidental, or consequential damages,
> + * with respect to any claim arising out or in connection with the use
> + * of the software, even if it has been or is hereafter advised of the
> + * possibility of such damages.
> + */
> +#include <linux/module.h>
> +#include <linux/init.h>
> +
> +#include <linux/nfs_fs.h>
> +#include <linux/pnfs_xdr.h> /* Needed by nfs4_pnfs.h */
> +#include <linux/nfs4_pnfs.h>
> +
> +#define NFSDBG_FACILITY         NFSDBG_BLOCKLAYOUT
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Andy Adamson <andros at citi.umich.edu>");
> +MODULE_DESCRIPTION("The NFSv4.1 pNFS Block layout driver");
> +
> +/* Callback operations to the pNFS client */
> +struct pnfs_client_operations *pnfs_callback_ops;
> +
> +static int
> +bl_commit(struct pnfs_layout_type *layoutid,
> +		int sync,
> +		struct nfs_write_data *nfs_data)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	/* Curently, this is only allowed to return:
> +	 *   0 - success
> +	 *   1 - fall back to non-pnfs commit
> +	 */
> +	return 1;
> +}
> +
> +static int
> +bl_read_pagelist(struct pnfs_layout_type *layoutid,
> +		struct page **pages,
> +		unsigned int pgbase,
> +		unsigned nr_pages,
> +		loff_t offset,
> +		size_t count,
> +		struct nfs_read_data *nfs_data)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return 1;
> +}
> +
> +/* FRED - this should return just 0 (to indicate done for now)
> + * or 1 (to indicate try normal nfs).  It can indicate bytes
> + * written in wdata->res.count.  It can indicate error status in
> + * wdata->task.tk_status.
> + */
> +static int
> +bl_write_pagelist(struct pnfs_layout_type *layoutid,
> +		struct page **pages,
> +		unsigned int pgbase,
> +		unsigned nr_pages,
> +		loff_t offset,
> +		size_t count,
> +		int sync,
> +		struct nfs_write_data *wdata)
> +{
> +	dprintk("%s enter - just using nfs\n", __FUNCTION__);
> +	return 1;
> +}
> +
> +static void
> +bl_free_layout(struct pnfs_layout_type *layoutid)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return;
> +}
> +
> +static struct pnfs_layout_type *
> +bl_alloc_layout(struct pnfs_mount_type *mtype, struct inode *inode)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return NULL;
> +}
> +
> +static void
> +bl_free_lseg(struct pnfs_layout_segment *lseg)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return;
> +}
> +
> +static struct pnfs_layout_segment *
> +bl_alloc_lseg(struct pnfs_layout_type *layoutid,
> +	      struct nfs4_pnfs_layoutget_res *lgr)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return NULL;
> +}
> +
> +static int
> +bl_setup_layoutcommit(struct pnfs_layout_type *layoutid,
> +		struct pnfs_layoutcommit_arg *arg)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return 0;
> +}
> +
> +static void
> +bl_cleanup_layoutcommit(struct pnfs_layout_type *layoutid,
> +		struct pnfs_layoutcommit_arg *arg,
> +		struct pnfs_layoutcommit_res *res)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +}
> +
> +static struct pnfs_mount_type *
> +bl_initialize_mountpoint(struct super_block *sb, struct nfs_fh *fh)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return NULL;
> +}
> +
> +static int
> +bl_uninitialize_mountpoint(struct pnfs_mount_type *mtype)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return 0;
> +}
> +
> +static ssize_t
> +bl_get_stripesize(struct pnfs_layout_type *layoutid)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return 0;
> +}
> +
> +static ssize_t
> +bl_get_io_threshold(struct pnfs_layout_type *layoutid, struct inode *inode)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return 0;
> +}
> +
> +/* This is called by nfs_can_coalesce_requests via nfs_pageio_do_add_request.
> + * Should return False if there is a reason requests can not be coalesced,
> + * otherwise, should default to returning True.
> + */
> +static int
> +bl_pg_test(struct nfs_pageio_descriptor *pgio, struct nfs_page *prev,
> +	   struct nfs_page *req)
> +{
> +	dprintk("%s enter\n", __FUNCTION__);
> +	return 1;
> +}
> +
> +static struct layoutdriver_io_operations blocklayout_io_operations = {
> +	.commit				= bl_commit,
> +	.read_pagelist			= bl_read_pagelist,
> +	.write_pagelist			= bl_write_pagelist,
> +	.alloc_layout			= bl_alloc_layout,
> +	.free_layout			= bl_free_layout,
> +	.alloc_lseg			= bl_alloc_lseg,
> +	.free_lseg			= bl_free_lseg,
> +	.setup_layoutcommit		= bl_setup_layoutcommit,
> +	.cleanup_layoutcommit		= bl_cleanup_layoutcommit,
> +	.initialize_mountpoint		= bl_initialize_mountpoint,
> +	.uninitialize_mountpoint	= bl_uninitialize_mountpoint,
> +};
> +
> +static struct layoutdriver_policy_operations blocklayout_policy_operations = {
> +	.get_stripesize			= bl_get_stripesize,
> +	.get_read_threshold		= bl_get_io_threshold,
> +	.get_write_threshold		= bl_get_io_threshold,
> +	.pg_test			= bl_pg_test,
> +};
> +
> +static struct pnfs_layoutdriver_type blocklayout_type = {
> +	.id = LAYOUT_BLOCK_VOLUME,
> +	.name = "LAYOUT_BLOCK_VOLUME",
> +	.ld_io_ops = &blocklayout_io_operations,
> +	.ld_policy_ops = &blocklayout_policy_operations,
> +};
> +
> +static int __init nfs4blocklayout_init(void)
> +{
> +	dprintk("%s: NFSv4 Block Layout Driver Registering...\n", __FUNCTION__);
> +
> +	pnfs_callback_ops = pnfs_register_layoutdriver(&blocklayout_type);
> +	return 0;
> +}
> +
> +static void __exit nfs4blocklayout_exit(void)
> +{
> +	dprintk("%s: NFSv4 Block Layout Driver Unregistering...\n",
> +	       __FUNCTION__);
> +
> +	pnfs_unregister_layoutdriver(&blocklayout_type);
> +}
> +
> +module_init(nfs4blocklayout_init);
> +module_exit(nfs4blocklayout_exit);
> +
> diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
> index 19bce5d..b778805 100644
> --- a/include/linux/nfs_fs.h
> +++ b/include/linux/nfs_fs.h
> @@ -608,6 +608,7 @@ extern void * nfs_root_data(void);
>  #define NFSDBG_PNFS		0x0800
>  #define NFSDBG_FILELAYOUT	0x1000
>  #define NFSDBG_IO		0x2000
> +#define NFSDBG_BLOCKLAYOUT	0x4000
>  #define NFSDBG_ALL		0xFFFF
>  
>  #ifdef __KERNEL__