/*
 *  pNFS client 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_PNFS_H
#define FS_NFS_PNFS_H

#include <linux/nfs_page.h>

enum {
        NFS_LSEG_VALID = 0,     /* cleared when lseg is recalled/returned */
        NFS_LSEG_ROC,           /* roc bit received from server */
};

struct pnfs_layout_segment {
        struct list_head pls_list;
        struct pnfs_layout_range pls_range;
        atomic_t pls_refcount;
        unsigned long pls_flags;
        struct pnfs_layout_hdr *pls_layout;
        struct rpc_cred *pls_lc_cred; /* LAYOUTCOMMIT credential */
        loff_t pls_end_pos; /* LAYOUTCOMMIT write end */
};

enum pnfs_try_status {
        PNFS_ATTEMPTED     = 0,
        PNFS_NOT_ATTEMPTED = 1,
};

#ifdef CONFIG_NFS_V4_1

#define LAYOUT_NFSV4_1_MODULE_PREFIX "nfs-layouttype4"

enum {
        NFS_LAYOUT_RO_FAILED = 0,       /* get ro layout failed stop trying */
        NFS_LAYOUT_RW_FAILED,           /* get rw layout failed stop trying */
        NFS_LAYOUT_BULK_RECALL,         /* bulk recall affecting layout */
        NFS_LAYOUT_ROC,                 /* some lseg had roc bit set */
        NFS_LAYOUT_DESTROYED,           /* no new use of layout allowed */
};

/* Per-layout driver specific registration structure */
struct pnfs_layoutdriver_type {
        struct list_head pnfs_tblid;
        const u32 id;
        const char *name;
        struct module *owner;
        struct pnfs_layout_segment * (*alloc_lseg) (struct pnfs_layout_hdr *layoutid, struct nfs4_layoutget_res *lgr, gfp_t gfp_flags);
        void (*free_lseg) (struct pnfs_layout_segment *lseg);

        /* test for nfs page cache coalescing */
        int (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);

        /* Returns true if layoutdriver wants to divert this request to
         * driver's commit routine.
         */
        bool (*mark_pnfs_commit)(struct pnfs_layout_segment *lseg);
        struct list_head * (*choose_commit_list) (struct nfs_page *req);
        int (*commit_pagelist)(struct inode *inode, struct list_head *mds_pages, int how);

        /*
         * Return PNFS_ATTEMPTED to indicate the layout code has attempted
         * I/O, else return PNFS_NOT_ATTEMPTED to fall back to normal NFS
         */
        enum pnfs_try_status (*read_pagelist) (struct nfs_read_data *nfs_data);
        enum pnfs_try_status (*write_pagelist) (struct nfs_write_data *nfs_data, int how);
};

struct pnfs_layout_hdr {
        atomic_t                plh_refcount;
        struct list_head        plh_layouts;   /* other client layouts */
        struct list_head        plh_bulk_recall; /* clnt list of bulk recalls */
        struct list_head        plh_segs;      /* layout segments list */
        nfs4_stateid            plh_stateid;
        atomic_t                plh_outstanding; /* number of RPCs out */
        unsigned long           plh_block_lgets; /* block LAYOUTGET if >0 */
        u32                     plh_barrier; /* ignore lower seqids */
        unsigned long           plh_flags;
        struct inode            *plh_inode;
};

struct pnfs_device {
        struct nfs4_deviceid dev_id;
        unsigned int  layout_type;
        unsigned int  mincount;
        struct page **pages;
        unsigned int  pgbase;
        unsigned int  pglen;
};

extern int pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *);
extern void pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *);

/* nfs4proc.c */
extern int nfs4_proc_getdeviceinfo(struct nfs_server *server,
                                   struct pnfs_device *dev);
extern int nfs4_proc_layoutget(struct nfs4_layoutget *lgp);

/* pnfs.c */
void get_layout_hdr(struct pnfs_layout_hdr *lo);
void put_lseg(struct pnfs_layout_segment *lseg);
struct pnfs_layout_segment *
pnfs_update_layout(struct inode *ino, struct nfs_open_context *ctx,
                   enum pnfs_iomode access_type, gfp_t gfp_flags);
void set_pnfs_layoutdriver(struct nfs_server *, u32 id);
void unset_pnfs_layoutdriver(struct nfs_server *);
enum pnfs_try_status pnfs_try_to_write_data(struct nfs_write_data *,
                                             const struct rpc_call_ops *, int);
enum pnfs_try_status pnfs_try_to_read_data(struct nfs_read_data *,
                                            const struct rpc_call_ops *);
void pnfs_pageio_init_read(struct nfs_pageio_descriptor *, struct inode *);
void pnfs_pageio_init_write(struct nfs_pageio_descriptor *, struct inode *);
int pnfs_layout_process(struct nfs4_layoutget *lgp);
void pnfs_free_lseg_list(struct list_head *tmp_list);
void pnfs_destroy_layout(struct nfs_inode *);
void pnfs_destroy_all_layouts(struct nfs_client *);
void put_layout_hdr(struct pnfs_layout_hdr *lo);
void pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo,
                             const nfs4_stateid *new,
                             bool update_barrier);
int pnfs_choose_layoutget_stateid(nfs4_stateid *dst,
                                  struct pnfs_layout_hdr *lo,
                                  struct nfs4_state *open_state);
int mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
                                struct list_head *tmp_list,
                                u32 iomode);
bool pnfs_roc(struct inode *ino);
void pnfs_roc_release(struct inode *ino);
void pnfs_roc_set_barrier(struct inode *ino, u32 barrier);
bool pnfs_roc_drain(struct inode *ino, u32 *barrier);
void pnfs_set_layoutcommit(struct nfs_write_data *wdata);
int pnfs_layoutcommit_inode(struct inode *inode, bool sync);

static inline int lo_fail_bit(u32 iomode)
{
        return iomode == IOMODE_RW ?
                         NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;
}

static inline struct pnfs_layout_segment *
get_lseg(struct pnfs_layout_segment *lseg)
{
        if (lseg) {
                atomic_inc(&lseg->pls_refcount);
                smp_mb__after_atomic_inc();
        }
        return lseg;
}

/* Return true if a layout driver is being used for this mountpoint */
static inline int pnfs_enabled_sb(struct nfs_server *nfss)
{
        return nfss->pnfs_curr_ld != NULL;
}

static inline void
pnfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
{
        if (lseg) {
                struct pnfs_layoutdriver_type *ld;

                ld = NFS_SERVER(req->wb_page->mapping->host)->pnfs_curr_ld;
                if (ld->mark_pnfs_commit && ld->mark_pnfs_commit(lseg)) {
                        set_bit(PG_PNFS_COMMIT, &req->wb_flags);
                        req->wb_commit_lseg = get_lseg(lseg);
                }
        }
}

static inline int
pnfs_commit_list(struct inode *inode, struct list_head *mds_pages, int how)
{
        if (!test_and_clear_bit(NFS_INO_PNFS_COMMIT, &NFS_I(inode)->flags))
                return PNFS_NOT_ATTEMPTED;
        return NFS_SERVER(inode)->pnfs_curr_ld->commit_pagelist(inode, mds_pages, how);
}

static inline struct list_head *
pnfs_choose_commit_list(struct nfs_page *req, struct list_head *mds)
{
        struct list_head *rv;

        if (test_and_clear_bit(PG_PNFS_COMMIT, &req->wb_flags)) {
                struct inode *inode = req->wb_commit_lseg->pls_layout->plh_inode;

                set_bit(NFS_INO_PNFS_COMMIT, &NFS_I(inode)->flags);
                rv = NFS_SERVER(inode)->pnfs_curr_ld->choose_commit_list(req);
                /* matched by ref taken when PG_PNFS_COMMIT is set */
                put_lseg(req->wb_commit_lseg);
        } else
                rv = mds;
        return rv;
}

static inline void pnfs_clear_request_commit(struct nfs_page *req)
{
        if (test_and_clear_bit(PG_PNFS_COMMIT, &req->wb_flags))
                put_lseg(req->wb_commit_lseg);
}

#else  /* CONFIG_NFS_V4_1 */

static inline void pnfs_destroy_all_layouts(struct nfs_client *clp)
{
}

static inline void pnfs_destroy_layout(struct nfs_inode *nfsi)
{
}

static inline struct pnfs_layout_segment *
get_lseg(struct pnfs_layout_segment *lseg)
{
        return NULL;
}

static inline void put_lseg(struct pnfs_layout_segment *lseg)
{
}

static inline struct pnfs_layout_segment *
pnfs_update_layout(struct inode *ino, struct nfs_open_context *ctx,
                   enum pnfs_iomode access_type, gfp_t gfp_flags)
{
        return NULL;
}

static inline enum pnfs_try_status
pnfs_try_to_read_data(struct nfs_read_data *data,
                      const struct rpc_call_ops *call_ops)
{
        return PNFS_NOT_ATTEMPTED;
}

static inline enum pnfs_try_status
pnfs_try_to_write_data(struct nfs_write_data *data,
                       const struct rpc_call_ops *call_ops, int how)
{
        return PNFS_NOT_ATTEMPTED;
}

static inline bool
pnfs_roc(struct inode *ino)
{
        return false;
}

static inline void
pnfs_roc_release(struct inode *ino)
{
}

static inline void
pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
{
}

static inline bool
pnfs_roc_drain(struct inode *ino, u32 *barrier)
{
        return false;
}

static inline void set_pnfs_layoutdriver(struct nfs_server *s, u32 id)
{
}

static inline void unset_pnfs_layoutdriver(struct nfs_server *s)
{
}

static inline void
pnfs_pageio_init_read(struct nfs_pageio_descriptor *pgio, struct inode *ino)
{
        pgio->pg_test = NULL;
}

static inline void
pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *ino)
{
        pgio->pg_test = NULL;
}

static inline void
pnfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
{
}

static inline int
pnfs_commit_list(struct inode *inode, struct list_head *mds_pages, int how)
{
        return PNFS_NOT_ATTEMPTED;
}

static inline struct list_head *
pnfs_choose_commit_list(struct nfs_page *req, struct list_head *mds)
{
        return mds;
}

static inline void pnfs_clear_request_commit(struct nfs_page *req)
{
}

static inline int pnfs_layoutcommit_inode(struct inode *inode, bool sync)
{
        return 0;
}
#endif /* CONFIG_NFS_V4_1 */

#endif /* FS_NFS_PNFS_H */