include/linux/nfs_page.h

   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  */
  25 enum {
  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
  41 struct nfs_inode;
  42 struct 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
  58 struct nfs_pgio_mirror;
  59 struct nfs_pageio_descriptor;
  60 struct 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
  73 struct 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
  84 struct 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
  93 struct 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
 120 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
 121                                             struct page *page,
 122                                             unsigned int offset,
 123                                             unsigned int count);
 124 extern  void nfs_release_request(struct nfs_page *);
 125
 126
 127 extern  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);
 134 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
 135                                    struct nfs_page *);
 136 extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
 137                               struct nfs_pgio_header *);
 138 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 139 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 140 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 141                                 struct nfs_page *prev,
 142                                 struct nfs_page *req);
 143 extern  int nfs_wait_on_request(struct nfs_page *);
 144 extern  void nfs_unlock_request(struct nfs_page *req);
 145 extern  void nfs_unlock_and_release_request(struct nfs_page *);
 146 extern  struct nfs_page *nfs_page_group_lock_head(struct nfs_page *req);
 147 extern  int nfs_page_group_lock_subrequests(struct nfs_page *head);
 148 extern  void nfs_join_page_group(struct nfs_page *head, struct inode *inode);
 149 extern int nfs_page_group_lock(struct nfs_page *);
 150 extern void nfs_page_group_unlock(struct nfs_page *);
 151 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
 152 extern  int nfs_page_set_headlock(struct nfs_page *req);
 153 extern void nfs_page_clear_headlock(struct nfs_page *req);
 154 extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *);
 155
 156 /*
 157  * Lock the page of an asynchronous request
 158  */
 159 static inline int
 160 nfs_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  */
 170 static inline void
 171 nfs_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  */
 181 static inline void
 182 nfs_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  */
 191 static inline void
 192 nfs_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
 199 static inline struct nfs_page *
 200 nfs_list_entry(struct list_head *head)
 201 {
 202         return list_entry(head, struct nfs_page, wb_list);
 203 }
 204
 205 static inline
 206 loff_t req_offset(struct nfs_page *req)
 207 {
 208         return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset;
 209 }
 210
 211 static inline struct nfs_open_context *
 212 nfs_req_openctx(struct nfs_page *req)
 213 {
 214         return req->wb_lock_context->open_context;
 215 }
 216
 217 #endif /* _LINUX_NFS_PAGE_H */