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_FOLIO,               /* Tracking a folio (unset for O_DIRECT) */
  29         PG_CLEAN,               /* write succeeded */
  30         PG_COMMIT_TO_DS,        /* used by pnfs layouts */
  31         PG_INODE_REF,           /* extra ref held by inode when in writeback */
  32         PG_HEADLOCK,            /* page group lock of wb_head */
  33         PG_TEARDOWN,            /* page group sync for destroy */
  34         PG_UNLOCKPAGE,          /* page group sync bit in read path */
  35         PG_UPTODATE,            /* page group sync bit in read path */
  36         PG_WB_END,              /* page group sync bit in write path */
  37         PG_REMOVE,              /* page group sync bit in write path */
  38         PG_CONTENDED1,          /* Is someone waiting for a lock? */
  39         PG_CONTENDED2,          /* Is someone waiting for a lock? */
  40 };
  41
  42 struct nfs_inode;
  43 struct nfs_page {
  44         struct list_head        wb_list;        /* Defines state of page: */
  45         union {
  46                 struct page     *wb_page;       /* page to read in/write out */
  47                 struct folio    *wb_folio;
  48         };
  49         struct nfs_lock_context *wb_lock_context;       /* lock context info */
  50         pgoff_t                 wb_index;       /* Offset >> PAGE_SHIFT */
  51         unsigned int            wb_offset,      /* Offset & ~PAGE_MASK */
  52                                 wb_pgbase,      /* Start of page data */
  53                                 wb_bytes;       /* Length of request */
  54         struct kref             wb_kref;        /* reference count */
  55         unsigned long           wb_flags;
  56         struct nfs_write_verifier       wb_verf;        /* Commit cookie */
  57         struct nfs_page         *wb_this_page;  /* list of reqs for this page */
  58         struct nfs_page         *wb_head;       /* head pointer for req list */
  59         unsigned short          wb_nio;         /* Number of I/O attempts */
  60 };
  61
  62 struct nfs_pgio_mirror;
  63 struct nfs_pageio_descriptor;
  64 struct nfs_pageio_ops {
  65         void    (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
  66         size_t  (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
  67                            struct nfs_page *);
  68         int     (*pg_doio)(struct nfs_pageio_descriptor *);
  69         unsigned int    (*pg_get_mirror_count)(struct nfs_pageio_descriptor *,
  70                                        struct nfs_page *);
  71         void    (*pg_cleanup)(struct nfs_pageio_descriptor *);
  72         struct nfs_pgio_mirror *
  73                 (*pg_get_mirror)(struct nfs_pageio_descriptor *, u32);
  74         u32     (*pg_set_mirror)(struct nfs_pageio_descriptor *, u32);
  75 };
  76
  77 struct nfs_rw_ops {
  78         struct nfs_pgio_header *(*rw_alloc_header)(void);
  79         void (*rw_free_header)(struct nfs_pgio_header *);
  80         int  (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
  81                         struct inode *);
  82         void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
  83         void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
  84                             const struct nfs_rpc_ops *,
  85                             struct rpc_task_setup *, int);
  86 };
  87
  88 struct nfs_pgio_mirror {
  89         struct list_head        pg_list;
  90         unsigned long           pg_bytes_written;
  91         size_t                  pg_count;
  92         size_t                  pg_bsize;
  93         unsigned int            pg_base;
  94         unsigned char           pg_recoalesce : 1;
  95 };
  96
  97 struct nfs_pageio_descriptor {
  98         struct inode            *pg_inode;
  99         const struct nfs_pageio_ops *pg_ops;
 100         const struct nfs_rw_ops *pg_rw_ops;
 101         int                     pg_ioflags;
 102         int                     pg_error;
 103         const struct rpc_call_ops *pg_rpc_callops;
 104         const struct nfs_pgio_completion_ops *pg_completion_ops;
 105         struct pnfs_layout_segment *pg_lseg;
 106         struct nfs_io_completion *pg_io_completion;
 107         struct nfs_direct_req   *pg_dreq;
 108 #ifdef CONFIG_NFS_FSCACHE
 109         void                    *pg_netfs;
 110 #endif
 111         unsigned int            pg_bsize;       /* default bsize for mirrors */
 112
 113         u32                     pg_mirror_count;
 114         struct nfs_pgio_mirror  *pg_mirrors;
 115         struct nfs_pgio_mirror  pg_mirrors_static[1];
 116         struct nfs_pgio_mirror  *pg_mirrors_dynamic;
 117         u32                     pg_mirror_idx;  /* current mirror */
 118         unsigned short          pg_maxretrans;
 119         unsigned char           pg_moreio : 1;
 120 };
 121
 122 /* arbitrarily selected limit to number of mirrors */
 123 #define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
 124
 125 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
 126
 127 extern struct nfs_page *nfs_page_create_from_page(struct nfs_open_context *ctx,
 128                                                   struct page *page,
 129                                                   unsigned int pgbase,
 130                                                   loff_t offset,
 131                                                   unsigned int count);
 132 extern struct nfs_page *nfs_page_create_from_folio(struct nfs_open_context *ctx,
 133                                                    struct folio *folio,
 134                                                    unsigned int offset,
 135                                                    unsigned int count);
 136 extern  void nfs_release_request(struct nfs_page *);
 137
 138
 139 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
 140                              struct inode *inode,
 141                              const struct nfs_pageio_ops *pg_ops,
 142                              const struct nfs_pgio_completion_ops *compl_ops,
 143                              const struct nfs_rw_ops *rw_ops,
 144                              size_t bsize,
 145                              int how);
 146 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
 147                                    struct nfs_page *);
 148 extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
 149                               struct nfs_pgio_header *);
 150 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
 151 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
 152 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 153                                 struct nfs_page *prev,
 154                                 struct nfs_page *req);
 155 extern  void nfs_unlock_request(struct nfs_page *req);
 156 extern  void nfs_unlock_and_release_request(struct nfs_page *);
 157 extern void nfs_join_page_group(struct nfs_page *head,
 158                                 struct nfs_commit_info *cinfo,
 159                                 struct inode *inode);
 160 extern int nfs_page_group_lock(struct nfs_page *);
 161 extern void nfs_page_group_unlock(struct nfs_page *);
 162 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
 163 extern  int nfs_page_set_headlock(struct nfs_page *req);
 164 extern void nfs_page_clear_headlock(struct nfs_page *req);
 165 extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *);
 166
 167 /**
 168  * nfs_page_to_folio - Retrieve a struct folio for the request
 169  * @req: pointer to a struct nfs_page
 170  *
 171  * If a folio was assigned to @req, then return it, otherwise return NULL.
 172  */
 173 static inline struct folio *nfs_page_to_folio(const struct nfs_page *req)
 174 {
 175         if (test_bit(PG_FOLIO, &req->wb_flags))
 176                 return req->wb_folio;
 177         return NULL;
 178 }
 179
 180 /**
 181  * nfs_page_to_page - Retrieve a struct page for the request
 182  * @req: pointer to a struct nfs_page
 183  * @pgbase: folio byte offset
 184  *
 185  * Return the page containing the byte that is at offset @pgbase relative
 186  * to the start of the folio.
 187  * Note: The request starts at offset @req->wb_pgbase.
 188  */
 189 static inline struct page *nfs_page_to_page(const struct nfs_page *req,
 190                                             size_t pgbase)
 191 {
 192         struct folio *folio = nfs_page_to_folio(req);
 193
 194         if (folio == NULL)
 195                 return req->wb_page;
 196         return folio_page(folio, pgbase >> PAGE_SHIFT);
 197 }
 198
 199 /**
 200  * nfs_page_to_inode - Retrieve an inode for the request
 201  * @req: pointer to a struct nfs_page
 202  */
 203 static inline struct inode *nfs_page_to_inode(const struct nfs_page *req)
 204 {
 205         struct folio *folio = nfs_page_to_folio(req);
 206
 207         if (folio == NULL)
 208                 return req->wb_page->mapping->host;
 209         return folio->mapping->host;
 210 }
 211
 212 /**
 213  * nfs_page_max_length - Retrieve the maximum possible length for a request
 214  * @req: pointer to a struct nfs_page
 215  *
 216  * Returns the maximum possible length of a request
 217  */
 218 static inline size_t nfs_page_max_length(const struct nfs_page *req)
 219 {
 220         struct folio *folio = nfs_page_to_folio(req);
 221
 222         if (folio == NULL)
 223                 return PAGE_SIZE;
 224         return folio_size(folio);
 225 }
 226
 227 /*
 228  * Lock the page of an asynchronous request
 229  */
 230 static inline int
 231 nfs_lock_request(struct nfs_page *req)
 232 {
 233         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 234 }
 235
 236 /**
 237  * nfs_list_add_request - Insert a request into a list
 238  * @req: request
 239  * @head: head of list into which to insert the request.
 240  */
 241 static inline void
 242 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 243 {
 244         list_add_tail(&req->wb_list, head);
 245 }
 246
 247 /**
 248  * nfs_list_move_request - Move a request to a new list
 249  * @req: request
 250  * @head: head of list into which to insert the request.
 251  */
 252 static inline void
 253 nfs_list_move_request(struct nfs_page *req, struct list_head *head)
 254 {
 255         list_move_tail(&req->wb_list, head);
 256 }
 257
 258 /**
 259  * nfs_list_remove_request - Remove a request from its wb_list
 260  * @req: request
 261  */
 262 static inline void
 263 nfs_list_remove_request(struct nfs_page *req)
 264 {
 265         if (list_empty(&req->wb_list))
 266                 return;
 267         list_del_init(&req->wb_list);
 268 }
 269
 270 static inline struct nfs_page *
 271 nfs_list_entry(struct list_head *head)
 272 {
 273         return list_entry(head, struct nfs_page, wb_list);
 274 }
 275
 276 static inline loff_t req_offset(const struct nfs_page *req)
 277 {
 278         return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset;
 279 }
 280
 281 static inline struct nfs_open_context *
 282 nfs_req_openctx(struct nfs_page *req)
 283 {
 284         return req->wb_lock_context->open_context;
 285 }
 286
 287 #endif /* _LINUX_NFS_PAGE_H */