LXR linux/include/linux/nfs

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * linux/include/linux/nfs_page.h
   4 *
   5 * Copyright (C) 2000 Trond Myklebust
   6 *
   7 * NFS page cache wrapper.
   8 */
   9
  10#ifndef _LINUX_NFS_PAGE_H
  11#define _LINUX_NFS_PAGE_H
  12
  13
  14#include <linux/list.h>
  15#include <linux/pagemap.h>
  16#include <linux/wait.h>
  17#include <linux/sunrpc/auth.h>
  18#include <linux/nfs_xdr.h>
  19
  20#include <linux/kref.h>
  21
  22/*
  23 * Valid flags for a dirty buffer
  24 */
  25enum {
  26        PG_BUSY = 0,            /* nfs_{un}lock_request */
  27        PG_MAPPED,              /* page private set for buffered io */
  28        PG_CLEAN,               /* write succeeded */
  29        PG_COMMIT_TO_DS,        /* used by pnfs layouts */
  30        PG_INODE_REF,           /* extra ref held by inode when in writeback */
  31        PG_HEADLOCK,            /* page group lock of wb_head */
  32        PG_TEARDOWN,            /* page group sync for destroy */
  33        PG_UNLOCKPAGE,          /* page group sync bit in read path */
  34        PG_UPTODATE,            /* page group sync bit in read path */
  35        PG_WB_END,              /* page group sync bit in write path */
  36        PG_REMOVE,              /* page group sync bit in write path */
  37        PG_CONTENDED1,          /* Is someone waiting for a lock? */
  38        PG_CONTENDED2,          /* Is someone waiting for a lock? */
  39};
  40
  41struct nfs_inode;
  42struct nfs_page {
  43        struct list_head        wb_list;        /* Defines state of page: */
  44        struct page             *wb_page;       /* page to read in/write out */
  45        struct nfs_lock_context *wb_lock_context;       /* lock context info */
  46        pgoff_t                 wb_index;       /* Offset >> PAGE_SHIFT */
  47        unsigned int            wb_offset,      /* Offset & ~PAGE_MASK */
  48                                wb_pgbase,      /* Start of page data */
  49                                wb_bytes;       /* Length of request */
  50        struct kref             wb_kref;        /* reference count */
  51        unsigned long           wb_flags;
  52        struct nfs_write_verifier       wb_verf;        /* Commit cookie */
  53        struct nfs_page         *wb_this_page;  /* list of reqs for this page */
  54        struct nfs_page         *wb_head;       /* head pointer for req list */
  55        unsigned short          wb_nio;         /* Number of I/O attempts */
  56};
  57
  58struct nfs_pgio_mirror;
  59struct nfs_pageio_descriptor;
  60struct nfs_pageio_ops {
  61        void    (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
  62        size_t  (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
  63                           struct nfs_page *);
  64        int     (*pg_doio)(struct nfs_pageio_descriptor *);
  65        unsigned int    (*pg_get_mirror_count)(struct nfs_pageio_descriptor *,
  66                                       struct nfs_page *);
  67        void    (*pg_cleanup)(struct nfs_pageio_descriptor *);
  68        struct nfs_pgio_mirror *
  69                (*pg_get_mirror)(struct nfs_pageio_descriptor *, u32);
  70        u32     (*pg_set_mirror)(struct nfs_pageio_descriptor *, u32);
  71};
  72
  73struct nfs_rw_ops {
  74        struct nfs_pgio_header *(*rw_alloc_header)(void);
  75        void (*rw_free_header)(struct nfs_pgio_header *);
  76        int  (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
  77                        struct inode *);
  78        void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
  79        void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
  80                            const struct nfs_rpc_ops *,
  81                            struct rpc_task_setup *, int);
  82};
  83
  84struct nfs_pgio_mirror {
  85        struct list_head        pg_list;
  86        unsigned long           pg_bytes_written;
  87        size_t                  pg_count;
  88        size_t                  pg_bsize;
  89        unsigned int            pg_base;
  90        unsigned char           pg_recoalesce : 1;
  91};
  92
  93struct nfs_pageio_descriptor {
  94        struct inode            *pg_inode;
  95        const struct nfs_pageio_ops *pg_ops;
  96        const struct nfs_rw_ops *pg_rw_ops;
  97        int                     pg_ioflags;
  98        int                     pg_error;
  99        const struct rpc_call_ops *pg_rpc_callops;
 100        const struct nfs_pgio_completion_ops *pg_completion_ops;
 101        struct pnfs_layout_segment *pg_lseg;
 102        struct nfs_io_completion *pg_io_completion;
 103        struct nfs_direct_req   *pg_dreq;
 104        unsigned int            pg_bsize;       /* default bsize for mirrors */
 105
 106        u32                     pg_mirror_count;
 107        struct nfs_pgio_mirror  *pg_mirrors;
 108        struct nfs_pgio_mirror  pg_mirrors_static[1];
 109        struct nfs_pgio_mirror  *pg_mirrors_dynamic;
 110        u32                     pg_mirror_idx;  /* current mirror */
 111        unsigned short          pg_maxretrans;
 112        unsigned char           pg_moreio : 1;
 113};
 114
 115/* arbitrarily selected limit to number of mirrors */
 116#define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
 117
 118#define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
 119
 120extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
 121                                            struct page *page,
 122                                            unsigned int offset,
 123                                            unsigned int count);
 124extern  void nfs_release_request(struct nfs_page *);
 125
 126
 127extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
 128                             struct inode *inode,
 129                             const struct nfs_pageio_ops *pg_ops,
 130                             const struct nfs_pgio_completion_ops *compl_ops,
 131                             const struct nfs_rw_ops *rw_ops,
 132                             size_t bsize,
 133                             int how);
 134extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
 135                                   struct nfs_page *);
 136extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
 137                              struct nfs_pgio_header *);
 138extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 139extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 140extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 141                                struct nfs_page *prev,
 142                                struct nfs_page *req);
 143extern  int nfs_wait_on_request(struct nfs_page *);
 144extern  void nfs_unlock_request(struct nfs_page *req);
 145extern  void nfs_unlock_and_release_request(struct nfs_page *);
 146extern  struct nfs_page *nfs_page_group_lock_head(struct nfs_page *req);
 147extern  int nfs_page_group_lock_subrequests(struct nfs_page *head);
 148extern  void nfs_join_page_group(struct nfs_page *head, struct inode *inode);
 149extern int nfs_page_group_lock(struct nfs_page *);
 150extern void nfs_page_group_unlock(struct nfs_page *);
 151extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
 152extern  int nfs_page_set_headlock(struct nfs_page *req);
 153extern void nfs_page_clear_headlock(struct nfs_page *req);
 154extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *);
 155
 156/*
 157 * Lock the page of an asynchronous request
 158 */
 159static inline int
 160nfs_lock_request(struct nfs_page *req)
 161{
 162        return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 163}
 164
 165/**
 166 * nfs_list_add_request - Insert a request into a list
 167 * @req: request
 168 * @head: head of list into which to insert the request.
 169 */
 170static inline void
 171nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 172{
 173        list_add_tail(&req->wb_list, head);
 174}
 175
 176/**
 177 * nfs_list_move_request - Move a request to a new list
 178 * @req: request
 179 * @head: head of list into which to insert the request.
 180 */
 181static inline void
 182nfs_list_move_request(struct nfs_page *req, struct list_head *head)
 183{
 184        list_move_tail(&req->wb_list, head);
 185}
 186
 187/**
 188 * nfs_list_remove_request - Remove a request from its wb_list
 189 * @req: request
 190 */
 191static inline void
 192nfs_list_remove_request(struct nfs_page *req)
 193{
 194        if (list_empty(&req->wb_list))
 195                return;
 196        list_del_init(&req->wb_list);
 197}
 198
 199static inline struct nfs_page *
 200nfs_list_entry(struct list_head *head)
 201{
 202        return list_entry(head, struct nfs_page, wb_list);
 203}
 204
 205static inline
 206loff_t req_offset(struct nfs_page *req)
 207{
 208        return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset;
 209}
 210
 211static inline struct nfs_open_context *
 212nfs_req_openctx(struct nfs_page *req)
 213{
 214        return req->wb_lock_context->open_context;
 215}
 216
 217#endif /* _LINUX_NFS_PAGE_H */
 218