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 unsigned int pg_bsize; /* default bsize for mirrors */ 109 110 u32 pg_mirror_count; 111 struct nfs_pgio_mirror *pg_mirrors; 112 struct nfs_pgio_mirror pg_mirrors_static[1]; 113 struct nfs_pgio_mirror *pg_mirrors_dynamic; 114 u32 pg_mirror_idx; /* current mirror */ 115 unsigned short pg_maxretrans; 116 unsigned char pg_moreio : 1; 117 }; 118 119 /* arbitrarily selected limit to number of mirrors */ 120 #define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16 121 122 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags)) 123 124 extern struct nfs_page *nfs_page_create_from_page(struct nfs_open_context *ctx, 125 struct page *page, 126 unsigned int pgbase, 127 loff_t offset, 128 unsigned int count); 129 extern struct nfs_page *nfs_page_create_from_folio(struct nfs_open_context *ctx, 130 struct folio *folio, 131 unsigned int offset, 132 unsigned int count); 133 extern void nfs_release_request(struct nfs_page *); 134 135 136 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 137 struct inode *inode, 138 const struct nfs_pageio_ops *pg_ops, 139 const struct nfs_pgio_completion_ops *compl_ops, 140 const struct nfs_rw_ops *rw_ops, 141 size_t bsize, 142 int how); 143 extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *, 144 struct nfs_page *); 145 extern int nfs_pageio_resend(struct nfs_pageio_descriptor *, 146 struct nfs_pgio_header *); 147 extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc); 148 extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t); 149 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, 150 struct nfs_page *prev, 151 struct nfs_page *req); 152 extern int nfs_wait_on_request(struct nfs_page *); 153 extern void nfs_unlock_request(struct nfs_page *req); 154 extern void nfs_unlock_and_release_request(struct nfs_page *); 155 extern struct nfs_page *nfs_page_group_lock_head(struct nfs_page *req); 156 extern int nfs_page_group_lock_subrequests(struct nfs_page *head); 157 extern void nfs_join_page_group(struct nfs_page *head, struct inode *inode); 158 extern int nfs_page_group_lock(struct nfs_page *); 159 extern void nfs_page_group_unlock(struct nfs_page *); 160 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int); 161 extern int nfs_page_set_headlock(struct nfs_page *req); 162 extern void nfs_page_clear_headlock(struct nfs_page *req); 163 extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *); 164 165 /** 166 * nfs_page_to_folio - Retrieve a struct folio for the request 167 * @req: pointer to a struct nfs_page 168 * 169 * If a folio was assigned to @req, then return it, otherwise return NULL. 170 */ 171 static inline struct folio *nfs_page_to_folio(const struct nfs_page *req) 172 { 173 if (test_bit(PG_FOLIO, &req->wb_flags)) 174 return req->wb_folio; 175 return NULL; 176 } 177 178 /** 179 * nfs_page_to_page - Retrieve a struct page for the request 180 * @req: pointer to a struct nfs_page 181 * @pgbase: folio byte offset 182 * 183 * Return the page containing the byte that is at offset @pgbase relative 184 * to the start of the folio. 185 * Note: The request starts at offset @req->wb_pgbase. 186 */ 187 static inline struct page *nfs_page_to_page(const struct nfs_page *req, 188 size_t pgbase) 189 { 190 struct folio *folio = nfs_page_to_folio(req); 191 192 if (folio == NULL) 193 return req->wb_page; 194 return folio_page(folio, pgbase >> PAGE_SHIFT); 195 } 196 197 /** 198 * nfs_page_to_inode - Retrieve an inode for the request 199 * @req: pointer to a struct nfs_page 200 */ 201 static inline struct inode *nfs_page_to_inode(const struct nfs_page *req) 202 { 203 struct folio *folio = nfs_page_to_folio(req); 204 205 if (folio == NULL) 206 return page_file_mapping(req->wb_page)->host; 207 return folio_file_mapping(folio)->host; 208 } 209 210 /** 211 * nfs_page_max_length - Retrieve the maximum possible length for a request 212 * @req: pointer to a struct nfs_page 213 * 214 * Returns the maximum possible length of a request 215 */ 216 static inline size_t nfs_page_max_length(const struct nfs_page *req) 217 { 218 struct folio *folio = nfs_page_to_folio(req); 219 220 if (folio == NULL) 221 return PAGE_SIZE; 222 return folio_size(folio); 223 } 224 225 /* 226 * Lock the page of an asynchronous request 227 */ 228 static inline int 229 nfs_lock_request(struct nfs_page *req) 230 { 231 return !test_and_set_bit(PG_BUSY, &req->wb_flags); 232 } 233 234 /** 235 * nfs_list_add_request - Insert a request into a list 236 * @req: request 237 * @head: head of list into which to insert the request. 238 */ 239 static inline void 240 nfs_list_add_request(struct nfs_page *req, struct list_head *head) 241 { 242 list_add_tail(&req->wb_list, head); 243 } 244 245 /** 246 * nfs_list_move_request - Move a request to a new list 247 * @req: request 248 * @head: head of list into which to insert the request. 249 */ 250 static inline void 251 nfs_list_move_request(struct nfs_page *req, struct list_head *head) 252 { 253 list_move_tail(&req->wb_list, head); 254 } 255 256 /** 257 * nfs_list_remove_request - Remove a request from its wb_list 258 * @req: request 259 */ 260 static inline void 261 nfs_list_remove_request(struct nfs_page *req) 262 { 263 if (list_empty(&req->wb_list)) 264 return; 265 list_del_init(&req->wb_list); 266 } 267 268 static inline struct nfs_page * 269 nfs_list_entry(struct list_head *head) 270 { 271 return list_entry(head, struct nfs_page, wb_list); 272 } 273 274 static inline loff_t req_offset(const struct nfs_page *req) 275 { 276 return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset; 277 } 278 279 static inline struct nfs_open_context * 280 nfs_req_openctx(struct nfs_page *req) 281 { 282 return req->wb_lock_context->open_context; 283 } 284 285 #endif /* _LINUX_NFS_PAGE_H */ 286