1. 根目录:
2. fs
3. nfs
4. nfs4filelayout.h

/*
 *  NFSv4 file layout driver data structures.
 *
 *  Copyright (c) 2002
 *  The Regents of the University of Michigan
 *  All Rights Reserved
 *
 *  Dean Hildebrand <dhildebz@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 or warranty
 *  of any kind either express or implied, including without limitation
 *  the implied warranties of merchantability, fitness for a particular
 *  purpose, or noninfringement.  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 of or in connection with the use of the software,
 *  even if it has been or is hereafter advised of the possibility of
 *  such damages.
 */

#ifndef FS_NFS_NFS4FILELAYOUT_H
#define FS_NFS_NFS4FILELAYOUT_H

#include "pnfs.h"

/*
 * Field testing shows we need to support up to 4096 stripe indices.
 * We store each index as a u8 (u32 on the wire) to keep the memory footprint
 * reasonable. This in turn means we support a maximum of 256
 * RFC 5661 multipath_list4 structures.
 */
#define NFS4_PNFS_MAX_STRIPE_CNT 4096
#define NFS4_PNFS_MAX_MULTI_CNT  256 /* 256 fit into a u8 stripe_index */

enum stripetype4 {
	STRIPE_SPARSE = 1,
	STRIPE_DENSE = 2
};

/* Individual ip address */
struct nfs4_pnfs_ds {
	struct list_head	ds_node;  /* nfs4_pnfs_dev_hlist dev_dslist */
	u32			ds_ip_addr;
	u32			ds_port;
	struct nfs_client	*ds_clp;
	atomic_t		ds_count;
};

/* nfs4_file_layout_dsaddr flags */
#define NFS4_DEVICE_ID_NEG_ENTRY	0x00000001

struct nfs4_file_layout_dsaddr {
	struct hlist_node		node;
	struct nfs4_deviceid		deviceid;
	atomic_t			ref;
	unsigned long			flags;
	u32				stripe_count;
	u8				*stripe_indices;
	u32				ds_num;
	struct nfs4_pnfs_ds		*ds_list[1];
};

struct nfs4_filelayout_segment {
	struct pnfs_layout_segment generic_hdr;
	u32 stripe_type;
	u32 commit_through_mds;
	u32 stripe_unit;
	u32 first_stripe_index;
	u64 pattern_offset;
	struct nfs4_file_layout_dsaddr *dsaddr; /* Point to GETDEVINFO data */
	unsigned int num_fh;
	struct nfs_fh **fh_array;
	struct list_head *commit_buckets; /* Sort commits to ds */
	int number_of_buckets;
};

static inline struct nfs4_filelayout_segment *
FILELAYOUT_LSEG(struct pnfs_layout_segment *lseg)
{
	return container_of(lseg,
			    struct nfs4_filelayout_segment,
			    generic_hdr);
}

extern struct nfs_fh *
nfs4_fl_select_ds_fh(struct pnfs_layout_segment *lseg, u32 j);

extern void print_ds(struct nfs4_pnfs_ds *ds);
extern void print_deviceid(struct nfs4_deviceid *dev_id);
u32 nfs4_fl_calc_j_index(struct pnfs_layout_segment *lseg, loff_t offset);
u32 nfs4_fl_calc_ds_index(struct pnfs_layout_segment *lseg, u32 j);
struct nfs4_pnfs_ds *nfs4_fl_prepare_ds(struct pnfs_layout_segment *lseg,
					u32 ds_idx);
extern struct nfs4_file_layout_dsaddr *
nfs4_fl_find_get_deviceid(struct nfs4_deviceid *dev_id);
extern void nfs4_fl_put_deviceid(struct nfs4_file_layout_dsaddr *dsaddr);
struct nfs4_file_layout_dsaddr *
get_device_info(struct inode *inode, struct nfs4_deviceid *dev_id, gfp_t gfp_flags);

#endif /* FS_NFS_NFS4FILELAYOUT_H */