/*
 *  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/refcount.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/workqueue.h>

struct nfs4_opendata;

enum {
        NFS_LSEG_VALID = 0,     /* cleared when lseg is recalled/returned */
        NFS_LSEG_ROC,           /* roc bit received from server */
        NFS_LSEG_LAYOUTCOMMIT,  /* layoutcommit bit set for layoutcommit */
        NFS_LSEG_LAYOUTRETURN,  /* layoutreturn bit set for layoutreturn */
        NFS_LSEG_UNAVAILABLE,   /* unavailable bit set for temporary problem */
};

/* Individual ip address */
struct nfs4_pnfs_ds_addr {
        struct sockaddr_storage da_addr;
        size_t                  da_addrlen;
        struct list_head        da_node;  /* nfs4_pnfs_dev_hlist dev_dslist */
        char                    *da_remotestr;  /* human readable addr+port */
};

struct nfs4_pnfs_ds {
        struct list_head        ds_node;  /* nfs4_pnfs_dev_hlist dev_dslist */
        char                    *ds_remotestr;  /* comma sep list of addrs */
        struct list_head        ds_addrs;
        struct nfs_client       *ds_clp;
        refcount_t              ds_count;
        unsigned long           ds_state;
#define NFS4DS_CONNECTING       0       /* ds is establishing connection */
};

struct pnfs_layout_segment {
        struct list_head pls_list;
        struct list_head pls_lc_list;
        struct pnfs_layout_range pls_range;
        refcount_t pls_refcount;
        u32 pls_seq;
        unsigned long pls_flags;
        struct pnfs_layout_hdr *pls_layout;
};

enum pnfs_try_status {
        PNFS_ATTEMPTED     = 0,
        PNFS_NOT_ATTEMPTED = 1,
        PNFS_TRY_AGAIN     = 2,
};

#ifdef CONFIG_NFS_V4_1

#define LAYOUT_NFSV4_1_MODULE_PREFIX "nfs-layouttype4"

/*
 * Default data server connection timeout and retrans vaules.
 * Set by module parameters dataserver_timeo and dataserver_retrans.
 */
#define NFS4_DEF_DS_TIMEO   600 /* in tenths of a second */
#define NFS4_DEF_DS_RETRANS 5
#define PNFS_DEVICE_RETRY_TIMEOUT (120*HZ)

/* error codes for internal use */
#define NFS4ERR_RESET_TO_MDS   12001
#define NFS4ERR_RESET_TO_PNFS  12002

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_RETURN,              /* layoutreturn in progress */
        NFS_LAYOUT_RETURN_LOCK,         /* Serialise layoutreturn */
        NFS_LAYOUT_RETURN_REQUESTED,    /* Return this layout ASAP */
        NFS_LAYOUT_INVALID_STID,        /* layout stateid id is invalid */
        NFS_LAYOUT_FIRST_LAYOUTGET,     /* Serialize first layoutget */
};

enum layoutdriver_policy_flags {
        /* Should the pNFS client commit and return the layout upon truncate to
         * a smaller size */
        PNFS_LAYOUTRET_ON_SETATTR       = 1 << 0,
        PNFS_LAYOUTRET_ON_ERROR         = 1 << 1,
        PNFS_READ_WHOLE_PAGE            = 1 << 2,
        PNFS_LAYOUTGET_ON_OPEN          = 1 << 3,
};

struct nfs4_deviceid_node;

/* Per-layout driver specific registration structure */
struct pnfs_layoutdriver_type {
        struct list_head pnfs_tblid;
        const u32 id;
        const char *name;
        struct module *owner;
        unsigned flags;
        unsigned max_deviceinfo_size;

        int (*set_layoutdriver) (struct nfs_server *, const struct nfs_fh *);
        int (*clear_layoutdriver) (struct nfs_server *);

        struct pnfs_layout_hdr * (*alloc_layout_hdr) (struct inode *inode, gfp_t gfp_flags);
        void (*free_layout_hdr) (struct pnfs_layout_hdr *);

        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);
        void (*add_lseg) (struct pnfs_layout_hdr *layoutid,
                        struct pnfs_layout_segment *lseg,
                        struct list_head *free_me);

        void (*return_range) (struct pnfs_layout_hdr *lo,
                              struct pnfs_layout_range *range);

        /* test for nfs page cache coalescing */
        const struct nfs_pageio_ops *pg_read_ops;
        const struct nfs_pageio_ops *pg_write_ops;

        struct pnfs_ds_commit_info *(*get_ds_info) (struct inode *inode);
        void (*mark_request_commit) (struct nfs_page *req,
                                     struct pnfs_layout_segment *lseg,
                                     struct nfs_commit_info *cinfo,
                                     u32 ds_commit_idx);
        void (*clear_request_commit) (struct nfs_page *req,
                                      struct nfs_commit_info *cinfo);
        int (*scan_commit_lists) (struct nfs_commit_info *cinfo,
                                  int max);
        void (*recover_commit_reqs) (struct list_head *list,
                                     struct nfs_commit_info *cinfo);
        struct nfs_page * (*search_commit_reqs)(struct nfs_commit_info *cinfo,
                                                struct page *page);
        int (*commit_pagelist)(struct inode *inode,
                               struct list_head *mds_pages,
                               int how,
                               struct nfs_commit_info *cinfo);

        int (*sync)(struct inode *inode, bool datasync);

        /*
         * 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_pgio_header *);
        enum pnfs_try_status (*write_pagelist)(struct nfs_pgio_header *, int);

        void (*free_deviceid_node) (struct nfs4_deviceid_node *);
        struct nfs4_deviceid_node * (*alloc_deviceid_node)
                        (struct nfs_server *server, struct pnfs_device *pdev,
                        gfp_t gfp_flags);

        int (*prepare_layoutreturn) (struct nfs4_layoutreturn_args *);

        void (*cleanup_layoutcommit) (struct nfs4_layoutcommit_data *data);
        int (*prepare_layoutcommit) (struct nfs4_layoutcommit_args *args);
        int (*prepare_layoutstats) (struct nfs42_layoutstat_args *args);
};

struct pnfs_layout_hdr {
        refcount_t              plh_refcount;
        atomic_t                plh_outstanding; /* number of RPCs out */
        struct list_head        plh_layouts;   /* other client layouts */
        struct list_head        plh_bulk_destroy;
        struct list_head        plh_segs;      /* layout segments list */
        struct list_head        plh_return_segs; /* invalid layout segments */
        unsigned long           plh_block_lgets; /* block LAYOUTGET if >0 */
        unsigned long           plh_retry_timestamp;
        unsigned long           plh_flags;
        nfs4_stateid            plh_stateid;
        u32                     plh_barrier; /* ignore lower seqids */
        u32                     plh_return_seq;
        enum pnfs_iomode        plh_return_iomode;
        loff_t                  plh_lwb; /* last write byte for layoutcommit */
        struct rpc_cred         *plh_lc_cred; /* layoutcommit cred */
        struct inode            *plh_inode;
};

struct pnfs_device {
        struct nfs4_deviceid dev_id;
        unsigned int  layout_type;
        unsigned int  mincount;
        unsigned int  maxcount; /* gdia_maxcount */
        struct page **pages;
        unsigned int  pgbase;
        unsigned int  pglen;    /* reply buffer length */
        unsigned char nocache : 1;/* May not be cached */
};

#define NFS4_PNFS_GETDEVLIST_MAXNUM 16

struct pnfs_devicelist {
        unsigned int            eof;
        unsigned int            num_devs;
        struct nfs4_deviceid    dev_id[NFS4_PNFS_GETDEVLIST_MAXNUM];
};

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

/* nfs4proc.c */
extern size_t max_response_pages(struct nfs_server *server);
extern int nfs4_proc_getdeviceinfo(struct nfs_server *server,
                                   struct pnfs_device *dev,
                                   struct rpc_cred *cred);
extern struct pnfs_layout_segment* nfs4_proc_layoutget(struct nfs4_layoutget *lgp, long *timeout);
extern int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp, bool sync);

/* pnfs.c */
void pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo);
void pnfs_put_lseg(struct pnfs_layout_segment *lseg);

void set_pnfs_layoutdriver(struct nfs_server *, const struct nfs_fh *, struct nfs_fsinfo *);
void unset_pnfs_layoutdriver(struct nfs_server *);
void pnfs_generic_pg_check_layout(struct nfs_pageio_descriptor *pgio);
void pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *, struct nfs_page *);
int pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc);
void pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
                                struct nfs_page *req, u64 wb_size);
void pnfs_generic_pg_cleanup(struct nfs_pageio_descriptor *);
int pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc);
size_t pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio,
                            struct nfs_page *prev, struct nfs_page *req);
void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg);
struct pnfs_layout_segment *pnfs_layout_process(struct nfs4_layoutget *lgp);
void pnfs_layoutget_free(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 *);
int pnfs_destroy_layouts_byfsid(struct nfs_client *clp,
                struct nfs_fsid *fsid,
                bool is_recall);
int pnfs_destroy_layouts_byclid(struct nfs_client *clp,
                bool is_recall);
bool nfs4_refresh_layout_stateid(nfs4_stateid *dst, struct inode *inode);
void pnfs_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_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
                                struct list_head *tmp_list,
                                const struct pnfs_layout_range *recall_range,
                                u32 seq);
int pnfs_mark_matching_lsegs_return(struct pnfs_layout_hdr *lo,
                                struct list_head *tmp_list,
                                const struct pnfs_layout_range *recall_range,
                                u32 seq);
int pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
                struct list_head *lseg_list);
bool pnfs_roc(struct inode *ino,
                struct nfs4_layoutreturn_args *args,
                struct nfs4_layoutreturn_res *res,
                const struct rpc_cred *cred);
void pnfs_roc_release(struct nfs4_layoutreturn_args *args,
                struct nfs4_layoutreturn_res *res,
                int ret);
bool pnfs_wait_on_layoutreturn(struct inode *ino, struct rpc_task *task);
void pnfs_set_layoutcommit(struct inode *, struct pnfs_layout_segment *, loff_t);
void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data);
int pnfs_layoutcommit_inode(struct inode *inode, bool sync);
int pnfs_generic_sync(struct inode *inode, bool datasync);
int pnfs_nfs_generic_sync(struct inode *inode, bool datasync);
int _pnfs_return_layout(struct inode *);
int pnfs_commit_and_return_layout(struct inode *);
void pnfs_ld_write_done(struct nfs_pgio_header *);
void pnfs_ld_read_done(struct nfs_pgio_header *);
void pnfs_read_resend_pnfs(struct nfs_pgio_header *);
struct pnfs_layout_segment *pnfs_update_layout(struct inode *ino,
                                               struct nfs_open_context *ctx,
                                               loff_t pos,
                                               u64 count,
                                               enum pnfs_iomode iomode,
                                               bool strict_iomode,
                                               gfp_t gfp_flags);
void pnfs_layoutreturn_free_lsegs(struct pnfs_layout_hdr *lo,
                const nfs4_stateid *arg_stateid,
                const struct pnfs_layout_range *range,
                const nfs4_stateid *stateid);

void pnfs_generic_layout_insert_lseg(struct pnfs_layout_hdr *lo,
                   struct pnfs_layout_segment *lseg,
                   bool (*is_after)(const struct pnfs_layout_range *lseg_range,
                           const struct pnfs_layout_range *old),
                   bool (*do_merge)(struct pnfs_layout_segment *lseg,
                           struct pnfs_layout_segment *old),
                   struct list_head *free_me);

void nfs4_deviceid_mark_client_invalid(struct nfs_client *clp);
int pnfs_read_done_resend_to_mds(struct nfs_pgio_header *);
int pnfs_write_done_resend_to_mds(struct nfs_pgio_header *);
struct nfs4_threshold *pnfs_mdsthreshold_alloc(void);
void pnfs_error_mark_layout_for_return(struct inode *inode,
                                       struct pnfs_layout_segment *lseg);
/* nfs4_deviceid_flags */
enum {
        NFS_DEVICEID_INVALID = 0,       /* set when MDS clientid recalled */
        NFS_DEVICEID_UNAVAILABLE,       /* device temporarily unavailable */
        NFS_DEVICEID_NOCACHE,           /* device may not be cached */
};

/* pnfs_dev.c */
struct nfs4_deviceid_node {
        struct hlist_node               node;
        struct hlist_node               tmpnode;
        const struct pnfs_layoutdriver_type *ld;
        const struct nfs_client         *nfs_client;
        unsigned long                   flags;
        unsigned long                   timestamp_unavailable;
        struct nfs4_deviceid            deviceid;
        struct rcu_head                 rcu;
        atomic_t                        ref;
};

struct nfs4_deviceid_node *
nfs4_find_get_deviceid(struct nfs_server *server,
                const struct nfs4_deviceid *id, struct rpc_cred *cred,
                gfp_t gfp_mask);
void nfs4_delete_deviceid(const struct pnfs_layoutdriver_type *, const struct nfs_client *, const struct nfs4_deviceid *);
void nfs4_init_deviceid_node(struct nfs4_deviceid_node *, struct nfs_server *,
                             const struct nfs4_deviceid *);
bool nfs4_put_deviceid_node(struct nfs4_deviceid_node *);
void nfs4_mark_deviceid_unavailable(struct nfs4_deviceid_node *node);
bool nfs4_test_deviceid_unavailable(struct nfs4_deviceid_node *node);
void nfs4_deviceid_purge_client(const struct nfs_client *);

/* pnfs_nfs.c */
void pnfs_generic_clear_request_commit(struct nfs_page *req,
                                       struct nfs_commit_info *cinfo);
void pnfs_generic_commit_release(void *calldata);
void pnfs_generic_prepare_to_resend_writes(struct nfs_commit_data *data);
void pnfs_generic_rw_release(void *data);
void pnfs_generic_recover_commit_reqs(struct list_head *dst,
                                      struct nfs_commit_info *cinfo);
int pnfs_generic_commit_pagelist(struct inode *inode,
                                 struct list_head *mds_pages,
                                 int how,
                                 struct nfs_commit_info *cinfo,
                                 int (*initiate_commit)(struct nfs_commit_data *data,
                                                        int how));
int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo, int max);
void pnfs_generic_write_commit_done(struct rpc_task *task, void *data);
void nfs4_pnfs_ds_put(struct nfs4_pnfs_ds *ds);
struct nfs4_pnfs_ds *nfs4_pnfs_ds_add(struct list_head *dsaddrs,
                                      gfp_t gfp_flags);
void nfs4_pnfs_v3_ds_connect_unload(void);
int nfs4_pnfs_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds,
                          struct nfs4_deviceid_node *devid, unsigned int timeo,
                          unsigned int retrans, u32 version, u32 minor_version);
struct nfs4_pnfs_ds_addr *nfs4_decode_mp_ds_addr(struct net *net,
                                                 struct xdr_stream *xdr,
                                                 gfp_t gfp_flags);
void pnfs_layout_mark_request_commit(struct nfs_page *req,
                                     struct pnfs_layout_segment *lseg,
                                     struct nfs_commit_info *cinfo,
                                     u32 ds_commit_idx);
void pnfs_lgopen_prepare(struct nfs4_opendata *data,
                         struct nfs_open_context *ctx);
void pnfs_parse_lgopen(struct inode *ino, struct nfs4_layoutget *lgp,
                       struct nfs_open_context *ctx);
void nfs4_lgopen_release(struct nfs4_layoutget *lgp);

static inline bool nfs_have_layout(struct inode *inode)
{
        return NFS_I(inode)->layout != NULL;
}

static inline bool pnfs_layout_is_valid(const struct pnfs_layout_hdr *lo)
{
        return test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags) == 0;
}

static inline struct nfs4_deviceid_node *
nfs4_get_deviceid(struct nfs4_deviceid_node *d)
{
        atomic_inc(&d->ref);
        return d;
}

static inline struct pnfs_layout_segment *
pnfs_get_lseg(struct pnfs_layout_segment *lseg)
{
        if (lseg) {
                refcount_inc(&lseg->pls_refcount);
                smp_mb__after_atomic();
        }
        return lseg;
}

static inline bool
pnfs_is_valid_lseg(struct pnfs_layout_segment *lseg)
{
        return test_bit(NFS_LSEG_VALID, &lseg->pls_flags) != 0;
}

/* 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 int
pnfs_commit_list(struct inode *inode, struct list_head *mds_pages, int how,
                 struct nfs_commit_info *cinfo)
{
        if (cinfo->ds == NULL || cinfo->ds->ncommitting == 0)
                return PNFS_NOT_ATTEMPTED;
        return NFS_SERVER(inode)->pnfs_curr_ld->commit_pagelist(inode, mds_pages, how, cinfo);
}

static inline struct pnfs_ds_commit_info *
pnfs_get_ds_info(struct inode *inode)
{
        struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;

        if (ld == NULL || ld->get_ds_info == NULL)
                return NULL;
        return ld->get_ds_info(inode);
}

static inline void
pnfs_generic_mark_devid_invalid(struct nfs4_deviceid_node *node)
{
        set_bit(NFS_DEVICEID_INVALID, &node->flags);
}

static inline bool
pnfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
                         struct nfs_commit_info *cinfo, u32 ds_commit_idx)
{
        struct inode *inode = d_inode(req->wb_context->dentry);
        struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;

        if (lseg == NULL || ld->mark_request_commit == NULL)
                return false;
        ld->mark_request_commit(req, lseg, cinfo, ds_commit_idx);
        return true;
}

static inline bool
pnfs_clear_request_commit(struct nfs_page *req, struct nfs_commit_info *cinfo)
{
        struct inode *inode = d_inode(req->wb_context->dentry);
        struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;

        if (ld == NULL || ld->clear_request_commit == NULL)
                return false;
        ld->clear_request_commit(req, cinfo);
        return true;
}

static inline int
pnfs_scan_commit_lists(struct inode *inode, struct nfs_commit_info *cinfo,
                       int max)
{
        if (cinfo->ds == NULL || cinfo->ds->nwritten == 0)
                return 0;
        else
                return NFS_SERVER(inode)->pnfs_curr_ld->scan_commit_lists(cinfo, max);
}

static inline struct nfs_page *
pnfs_search_commit_reqs(struct inode *inode, struct nfs_commit_info *cinfo,
                        struct page *page)
{
        struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;

        if (ld == NULL || ld->search_commit_reqs == NULL)
                return NULL;
        return ld->search_commit_reqs(cinfo, page);
}

/* Should the pNFS client commit and return the layout upon a setattr */
static inline bool
pnfs_ld_layoutret_on_setattr(struct inode *inode)
{
        if (!pnfs_enabled_sb(NFS_SERVER(inode)))
                return false;
        return NFS_SERVER(inode)->pnfs_curr_ld->flags &
                PNFS_LAYOUTRET_ON_SETATTR;
}

static inline bool
pnfs_ld_read_whole_page(struct inode *inode)
{
        if (!pnfs_enabled_sb(NFS_SERVER(inode)))
                return false;
        return NFS_SERVER(inode)->pnfs_curr_ld->flags & PNFS_READ_WHOLE_PAGE;
}

static inline int
pnfs_sync_inode(struct inode *inode, bool datasync)
{
        if (!pnfs_enabled_sb(NFS_SERVER(inode)))
                return 0;
        return NFS_SERVER(inode)->pnfs_curr_ld->sync(inode, datasync);
}

static inline bool
pnfs_layoutcommit_outstanding(struct inode *inode)
{
        struct nfs_inode *nfsi = NFS_I(inode);

        return test_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags) != 0 ||
                test_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags) != 0;
}

static inline int pnfs_return_layout(struct inode *ino)
{
        struct nfs_inode *nfsi = NFS_I(ino);
        struct nfs_server *nfss = NFS_SERVER(ino);

        if (pnfs_enabled_sb(nfss) && nfsi->layout) {
                set_bit(NFS_LAYOUT_RETURN_REQUESTED, &nfsi->layout->plh_flags);
                return _pnfs_return_layout(ino);
        }

        return 0;
}

static inline bool
pnfs_use_threshold(struct nfs4_threshold **dst, struct nfs4_threshold *src,
                   struct nfs_server *nfss)
{
        return (dst && src && src->bm != 0 && nfss->pnfs_curr_ld &&
                                        nfss->pnfs_curr_ld->id == src->l_type);
}

static inline u64
pnfs_calc_offset_end(u64 offset, u64 len)
{
        if (len == NFS4_MAX_UINT64 || len >= NFS4_MAX_UINT64 - offset)
                return NFS4_MAX_UINT64;
        return offset + len - 1;
}

static inline u64
pnfs_calc_offset_length(u64 offset, u64 end)
{
        if (end == NFS4_MAX_UINT64 || end <= offset)
                return NFS4_MAX_UINT64;
        return 1 + end - offset;
}

static inline void
pnfs_copy_range(struct pnfs_layout_range *dst,
                const struct pnfs_layout_range *src)
{
        memcpy(dst, src, sizeof(*dst));
}

static inline u64
pnfs_end_offset(u64 start, u64 len)
{
        if (NFS4_MAX_UINT64 - start <= len)
                return NFS4_MAX_UINT64;
        return start + len;
}

/*
 * Are 2 ranges intersecting?
 *   start1                             end1
 *   [----------------------------------)
 *                                start2           end2
 *                                [----------------)
 */
static inline bool
pnfs_is_range_intersecting(u64 start1, u64 end1, u64 start2, u64 end2)
{
        return (end1 == NFS4_MAX_UINT64 || start2 < end1) &&
                (end2 == NFS4_MAX_UINT64 || start1 < end2);
}

static inline bool
pnfs_lseg_range_intersecting(const struct pnfs_layout_range *l1,
                const struct pnfs_layout_range *l2)
{
        u64 end1 = pnfs_end_offset(l1->offset, l1->length);
        u64 end2 = pnfs_end_offset(l2->offset, l2->length);

        return pnfs_is_range_intersecting(l1->offset, end1, l2->offset, end2);
}

static inline bool
pnfs_lseg_request_intersecting(struct pnfs_layout_segment *lseg, struct nfs_page *req)
{
        u64 seg_last = pnfs_end_offset(lseg->pls_range.offset, lseg->pls_range.length);
        u64 req_last = req_offset(req) + req->wb_bytes;

        return pnfs_is_range_intersecting(lseg->pls_range.offset, seg_last,
                                req_offset(req), req_last);
}

extern unsigned int layoutstats_timer;

#ifdef NFS_DEBUG
void nfs4_print_deviceid(const struct nfs4_deviceid *dev_id);
#else
static inline void nfs4_print_deviceid(const struct nfs4_deviceid *dev_id)
{
}

#endif /* NFS_DEBUG */
#else  /* CONFIG_NFS_V4_1 */

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

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 *
pnfs_get_lseg(struct pnfs_layout_segment *lseg)
{
        return NULL;
}

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

static inline int pnfs_return_layout(struct inode *ino)
{
        return 0;
}

static inline int pnfs_commit_and_return_layout(struct inode *inode)
{
        return 0;
}

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

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

static inline int
pnfs_sync_inode(struct inode *inode, bool datasync)
{
        return 0;
}

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


static inline bool
pnfs_roc(struct inode *ino,
                struct nfs4_layoutreturn_args *args,
                struct nfs4_layoutreturn_res *res,
                const struct rpc_cred *cred)
{
        return false;
}

static inline void
pnfs_roc_release(struct nfs4_layoutreturn_args *args,
                struct nfs4_layoutreturn_res *res,
                int ret)
{
}

static inline bool
pnfs_wait_on_layoutreturn(struct inode *ino, struct rpc_task *task)
{
        return false;
}

static inline void set_pnfs_layoutdriver(struct nfs_server *s,
                                         const struct nfs_fh *mntfh,
                                         struct nfs_fsinfo *fsinfo)
{
}

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

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

static inline struct pnfs_ds_commit_info *
pnfs_get_ds_info(struct inode *inode)
{
        return NULL;
}

static inline bool
pnfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
                         struct nfs_commit_info *cinfo, u32 ds_commit_idx)
{
        return false;
}

static inline bool
pnfs_clear_request_commit(struct nfs_page *req, struct nfs_commit_info *cinfo)
{
        return false;
}

static inline int
pnfs_scan_commit_lists(struct inode *inode, struct nfs_commit_info *cinfo,
                       int max)
{
        return 0;
}

static inline struct nfs_page *
pnfs_search_commit_reqs(struct inode *inode, struct nfs_commit_info *cinfo,
                        struct page *page)
{
        return NULL;
}

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

static inline bool
pnfs_use_threshold(struct nfs4_threshold **dst, struct nfs4_threshold *src,
                   struct nfs_server *nfss)
{
        return false;
}

static inline struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
{
        return NULL;
}

static inline void nfs4_pnfs_v3_ds_connect_unload(void)
{
}

static inline bool nfs4_refresh_layout_stateid(nfs4_stateid *dst,
                struct inode *inode)
{
        return false;
}

static inline void pnfs_lgopen_prepare(struct nfs4_opendata *data,
                struct nfs_open_context *ctx)
{
}

static inline void pnfs_parse_lgopen(struct inode *ino,
                struct nfs4_layoutget *lgp,
                struct nfs_open_context *ctx)
{
}

static inline void nfs4_lgopen_release(struct nfs4_layoutget *lgp)
{
}

static inline bool pnfs_layout_is_valid(const struct pnfs_layout_hdr *lo)
{
        return false;
}

#endif /* CONFIG_NFS_V4_1 */

#if IS_ENABLED(CONFIG_NFS_V4_2)
int pnfs_report_layoutstat(struct inode *inode, gfp_t gfp_flags);
#else
static inline int
pnfs_report_layoutstat(struct inode *inode, gfp_t gfp_flags)
{
        return 0;
}
#endif

#endif /* FS_NFS_PNFS_H */