1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* Network filesystem support services. 3 * 4 * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells ([email protected]) 6 * 7 * See: 8 * 9 * Documentation/filesystems/netfs_library.rst 10 * 11 * for a description of the network filesystem interface declared here. 12 */ 13 14 #ifndef _LINUX_NETFS_H 15 #define _LINUX_NETFS_H 16 17 #include <linux/workqueue.h> 18 #include <linux/fs.h> 19 #include <linux/pagemap.h> 20 #include <linux/uio.h> 21 #include <linux/rolling_buffer.h> 22 23 enum netfs_sreq_ref_trace; 24 typedef struct mempool_s mempool_t; 25 struct folio_queue; 26 27 /** 28 * folio_start_private_2 - Start an fscache write on a folio. [DEPRECATED] 29 * @folio: The folio. 30 * 31 * Call this function before writing a folio to a local cache. Starting a 32 * second write before the first one finishes is not allowed. 33 * 34 * Note that this should no longer be used. 35 */ 36 static inline void folio_start_private_2(struct folio *folio) 37 { 38 VM_BUG_ON_FOLIO(folio_test_private_2(folio), folio); 39 folio_get(folio); 40 folio_set_private_2(folio); 41 } 42 43 enum netfs_io_source { 44 NETFS_SOURCE_UNKNOWN, 45 NETFS_FILL_WITH_ZEROES, 46 NETFS_DOWNLOAD_FROM_SERVER, 47 NETFS_READ_FROM_CACHE, 48 NETFS_INVALID_READ, 49 NETFS_UPLOAD_TO_SERVER, 50 NETFS_WRITE_TO_CACHE, 51 NETFS_INVALID_WRITE, 52 } __mode(byte); 53 54 typedef void (*netfs_io_terminated_t)(void *priv, ssize_t transferred_or_error, 55 bool was_async); 56 57 /* 58 * Per-inode context. This wraps the VFS inode. 59 */ 60 struct netfs_inode { 61 struct inode inode; /* The VFS inode */ 62 const struct netfs_request_ops *ops; 63 #if IS_ENABLED(CONFIG_FSCACHE) 64 struct fscache_cookie *cache; 65 #endif 66 struct mutex wb_lock; /* Writeback serialisation */ 67 loff_t remote_i_size; /* Size of the remote file */ 68 loff_t zero_point; /* Size after which we assume there's no data 69 * on the server */ 70 atomic_t io_count; /* Number of outstanding reqs */ 71 unsigned long flags; 72 #define NETFS_ICTX_ODIRECT 0 /* The file has DIO in progress */ 73 #define NETFS_ICTX_UNBUFFERED 1 /* I/O should not use the pagecache */ 74 #define NETFS_ICTX_WRITETHROUGH 2 /* Write-through caching */ 75 #define NETFS_ICTX_MODIFIED_ATTR 3 /* Indicate change in mtime/ctime */ 76 }; 77 78 /* 79 * A netfs group - for instance a ceph snap. This is marked on dirty pages and 80 * pages marked with a group must be flushed before they can be written under 81 * the domain of another group. 82 */ 83 struct netfs_group { 84 refcount_t ref; 85 void (*free)(struct netfs_group *netfs_group); 86 }; 87 88 /* 89 * Information about a dirty page (attached only if necessary). 90 * folio->private 91 */ 92 struct netfs_folio { 93 struct netfs_group *netfs_group; /* Filesystem's grouping marker (or NULL). */ 94 unsigned int dirty_offset; /* Write-streaming dirty data offset */ 95 unsigned int dirty_len; /* Write-streaming dirty data length */ 96 }; 97 #define NETFS_FOLIO_INFO 0x1UL /* OR'd with folio->private. */ 98 #define NETFS_FOLIO_COPY_TO_CACHE ((struct netfs_group *)0x356UL) /* Write to the cache only */ 99 100 static inline bool netfs_is_folio_info(const void *priv) 101 { 102 return (unsigned long)priv & NETFS_FOLIO_INFO; 103 } 104 105 static inline struct netfs_folio *__netfs_folio_info(const void *priv) 106 { 107 if (netfs_is_folio_info(priv)) 108 return (struct netfs_folio *)((unsigned long)priv & ~NETFS_FOLIO_INFO); 109 return NULL; 110 } 111 112 static inline struct netfs_folio *netfs_folio_info(struct folio *folio) 113 { 114 return __netfs_folio_info(folio_get_private(folio)); 115 } 116 117 static inline struct netfs_group *netfs_folio_group(struct folio *folio) 118 { 119 struct netfs_folio *finfo; 120 void *priv = folio_get_private(folio); 121 122 finfo = netfs_folio_info(folio); 123 if (finfo) 124 return finfo->netfs_group; 125 return priv; 126 } 127 128 /* 129 * Stream of I/O subrequests going to a particular destination, such as the 130 * server or the local cache. This is mainly intended for writing where we may 131 * have to write to multiple destinations concurrently. 132 */ 133 struct netfs_io_stream { 134 /* Submission tracking */ 135 struct netfs_io_subrequest *construct; /* Op being constructed */ 136 size_t sreq_max_len; /* Maximum size of a subrequest */ 137 unsigned int sreq_max_segs; /* 0 or max number of segments in an iterator */ 138 unsigned int submit_off; /* Folio offset we're submitting from */ 139 unsigned int submit_len; /* Amount of data left to submit */ 140 unsigned int submit_extendable_to; /* Amount I/O can be rounded up to */ 141 void (*prepare_write)(struct netfs_io_subrequest *subreq); 142 void (*issue_write)(struct netfs_io_subrequest *subreq); 143 /* Collection tracking */ 144 struct list_head subrequests; /* Contributory I/O operations */ 145 struct netfs_io_subrequest *front; /* Op being collected */ 146 unsigned long long collected_to; /* Position we've collected results to */ 147 size_t transferred; /* The amount transferred from this stream */ 148 enum netfs_io_source source; /* Where to read from/write to */ 149 unsigned short error; /* Aggregate error for the stream */ 150 unsigned char stream_nr; /* Index of stream in parent table */ 151 bool avail; /* T if stream is available */ 152 bool active; /* T if stream is active */ 153 bool need_retry; /* T if this stream needs retrying */ 154 bool failed; /* T if this stream failed */ 155 }; 156 157 /* 158 * Resources required to do operations on a cache. 159 */ 160 struct netfs_cache_resources { 161 const struct netfs_cache_ops *ops; 162 void *cache_priv; 163 void *cache_priv2; 164 unsigned int debug_id; /* Cookie debug ID */ 165 unsigned int inval_counter; /* object->inval_counter at begin_op */ 166 }; 167 168 /* 169 * Descriptor for a single component subrequest. Each operation represents an 170 * individual read/write from/to a server, a cache, a journal, etc.. 171 * 172 * The buffer iterator is persistent for the life of the subrequest struct and 173 * the pages it points to can be relied on to exist for the duration. 174 */ 175 struct netfs_io_subrequest { 176 struct netfs_io_request *rreq; /* Supervising I/O request */ 177 struct work_struct work; 178 struct list_head rreq_link; /* Link in rreq->subrequests */ 179 struct iov_iter io_iter; /* Iterator for this subrequest */ 180 unsigned long long start; /* Where to start the I/O */ 181 size_t len; /* Size of the I/O */ 182 size_t transferred; /* Amount of data transferred */ 183 size_t consumed; /* Amount of read data consumed */ 184 size_t prev_donated; /* Amount of data donated from previous subreq */ 185 size_t next_donated; /* Amount of data donated from next subreq */ 186 refcount_t ref; 187 short error; /* 0 or error that occurred */ 188 unsigned short debug_index; /* Index in list (for debugging output) */ 189 unsigned int nr_segs; /* Number of segs in io_iter */ 190 u8 retry_count; /* The number of retries (0 on initial pass) */ 191 enum netfs_io_source source; /* Where to read from/write to */ 192 unsigned char stream_nr; /* I/O stream this belongs to */ 193 unsigned char curr_folioq_slot; /* Folio currently being read */ 194 unsigned char curr_folio_order; /* Order of folio */ 195 struct folio_queue *curr_folioq; /* Queue segment in which current folio resides */ 196 unsigned long flags; 197 #define NETFS_SREQ_COPY_TO_CACHE 0 /* Set if should copy the data to the cache */ 198 #define NETFS_SREQ_CLEAR_TAIL 1 /* Set if the rest of the read should be cleared */ 199 #define NETFS_SREQ_SEEK_DATA_READ 3 /* Set if ->read() should SEEK_DATA first */ 200 #define NETFS_SREQ_MADE_PROGRESS 4 /* Set if we transferred at least some data */ 201 #define NETFS_SREQ_ONDEMAND 5 /* Set if it's from on-demand read mode */ 202 #define NETFS_SREQ_BOUNDARY 6 /* Set if ends on hard boundary (eg. ceph object) */ 203 #define NETFS_SREQ_HIT_EOF 7 /* Set if short due to EOF */ 204 #define NETFS_SREQ_IN_PROGRESS 8 /* Unlocked when the subrequest completes */ 205 #define NETFS_SREQ_NEED_RETRY 9 /* Set if the filesystem requests a retry */ 206 #define NETFS_SREQ_FAILED 10 /* Set if the subreq failed unretryably */ 207 }; 208 209 enum netfs_io_origin { 210 NETFS_READAHEAD, /* This read was triggered by readahead */ 211 NETFS_READPAGE, /* This read is a synchronous read */ 212 NETFS_READ_GAPS, /* This read is a synchronous read to fill gaps */ 213 NETFS_READ_FOR_WRITE, /* This read is to prepare a write */ 214 NETFS_DIO_READ, /* This is a direct I/O read */ 215 NETFS_WRITEBACK, /* This write was triggered by writepages */ 216 NETFS_WRITETHROUGH, /* This write was made by netfs_perform_write() */ 217 NETFS_UNBUFFERED_WRITE, /* This is an unbuffered write */ 218 NETFS_DIO_WRITE, /* This is a direct I/O write */ 219 NETFS_PGPRIV2_COPY_TO_CACHE, /* [DEPRECATED] This is writing read data to the cache */ 220 nr__netfs_io_origin 221 } __mode(byte); 222 223 /* 224 * Descriptor for an I/O helper request. This is used to make multiple I/O 225 * operations to a variety of data stores and then stitch the result together. 226 */ 227 struct netfs_io_request { 228 union { 229 struct work_struct work; 230 struct rcu_head rcu; 231 }; 232 struct inode *inode; /* The file being accessed */ 233 struct address_space *mapping; /* The mapping being accessed */ 234 struct kiocb *iocb; /* AIO completion vector */ 235 struct netfs_cache_resources cache_resources; 236 struct readahead_control *ractl; /* Readahead descriptor */ 237 struct list_head proc_link; /* Link in netfs_iorequests */ 238 struct list_head subrequests; /* Contributory I/O operations */ 239 struct netfs_io_stream io_streams[2]; /* Streams of parallel I/O operations */ 240 #define NR_IO_STREAMS 2 //wreq->nr_io_streams 241 struct netfs_group *group; /* Writeback group being written back */ 242 struct rolling_buffer buffer; /* Unencrypted buffer */ 243 #define NETFS_ROLLBUF_PUT_MARK ROLLBUF_MARK_1 244 #define NETFS_ROLLBUF_PAGECACHE_MARK ROLLBUF_MARK_2 245 void *netfs_priv; /* Private data for the netfs */ 246 void *netfs_priv2; /* Private data for the netfs */ 247 struct bio_vec *direct_bv; /* DIO buffer list (when handling iovec-iter) */ 248 unsigned int direct_bv_count; /* Number of elements in direct_bv[] */ 249 unsigned int debug_id; 250 unsigned int rsize; /* Maximum read size (0 for none) */ 251 unsigned int wsize; /* Maximum write size (0 for none) */ 252 atomic_t subreq_counter; /* Next subreq->debug_index */ 253 unsigned int nr_group_rel; /* Number of refs to release on ->group */ 254 spinlock_t lock; /* Lock for queuing subreqs */ 255 atomic_t nr_outstanding; /* Number of ops in progress */ 256 unsigned long long submitted; /* Amount submitted for I/O so far */ 257 unsigned long long len; /* Length of the request */ 258 size_t transferred; /* Amount to be indicated as transferred */ 259 long error; /* 0 or error that occurred */ 260 enum netfs_io_origin origin; /* Origin of the request */ 261 bool direct_bv_unpin; /* T if direct_bv[] must be unpinned */ 262 unsigned long long i_size; /* Size of the file */ 263 unsigned long long start; /* Start position */ 264 atomic64_t issued_to; /* Write issuer folio cursor */ 265 unsigned long long collected_to; /* Point we've collected to */ 266 unsigned long long cleaned_to; /* Position we've cleaned folios to */ 267 pgoff_t no_unlock_folio; /* Don't unlock this folio after read */ 268 size_t prev_donated; /* Fallback for subreq->prev_donated */ 269 refcount_t ref; 270 unsigned long flags; 271 #define NETFS_RREQ_NO_UNLOCK_FOLIO 2 /* Don't unlock no_unlock_folio on completion */ 272 #define NETFS_RREQ_DONT_UNLOCK_FOLIOS 3 /* Don't unlock the folios on completion */ 273 #define NETFS_RREQ_FAILED 4 /* The request failed */ 274 #define NETFS_RREQ_IN_PROGRESS 5 /* Unlocked when the request completes */ 275 #define NETFS_RREQ_UPLOAD_TO_SERVER 8 /* Need to write to the server */ 276 #define NETFS_RREQ_NONBLOCK 9 /* Don't block if possible (O_NONBLOCK) */ 277 #define NETFS_RREQ_BLOCKED 10 /* We blocked */ 278 #define NETFS_RREQ_PAUSE 11 /* Pause subrequest generation */ 279 #define NETFS_RREQ_USE_IO_ITER 12 /* Use ->io_iter rather than ->i_pages */ 280 #define NETFS_RREQ_ALL_QUEUED 13 /* All subreqs are now queued */ 281 #define NETFS_RREQ_NEED_RETRY 14 /* Need to try retrying */ 282 #define NETFS_RREQ_USE_PGPRIV2 31 /* [DEPRECATED] Use PG_private_2 to mark 283 * write to cache on read */ 284 const struct netfs_request_ops *netfs_ops; 285 void (*cleanup)(struct netfs_io_request *req); 286 }; 287 288 /* 289 * Operations the network filesystem can/must provide to the helpers. 290 */ 291 struct netfs_request_ops { 292 mempool_t *request_pool; 293 mempool_t *subrequest_pool; 294 int (*init_request)(struct netfs_io_request *rreq, struct file *file); 295 void (*free_request)(struct netfs_io_request *rreq); 296 void (*free_subrequest)(struct netfs_io_subrequest *rreq); 297 298 /* Read request handling */ 299 void (*expand_readahead)(struct netfs_io_request *rreq); 300 int (*prepare_read)(struct netfs_io_subrequest *subreq); 301 void (*issue_read)(struct netfs_io_subrequest *subreq); 302 bool (*is_still_valid)(struct netfs_io_request *rreq); 303 int (*check_write_begin)(struct file *file, loff_t pos, unsigned len, 304 struct folio **foliop, void **_fsdata); 305 void (*done)(struct netfs_io_request *rreq); 306 307 /* Modification handling */ 308 void (*update_i_size)(struct inode *inode, loff_t i_size); 309 void (*post_modify)(struct inode *inode); 310 311 /* Write request handling */ 312 void (*begin_writeback)(struct netfs_io_request *wreq); 313 void (*prepare_write)(struct netfs_io_subrequest *subreq); 314 void (*issue_write)(struct netfs_io_subrequest *subreq); 315 void (*retry_request)(struct netfs_io_request *wreq, struct netfs_io_stream *stream); 316 void (*invalidate_cache)(struct netfs_io_request *wreq); 317 }; 318 319 /* 320 * How to handle reading from a hole. 321 */ 322 enum netfs_read_from_hole { 323 NETFS_READ_HOLE_IGNORE, 324 NETFS_READ_HOLE_CLEAR, 325 NETFS_READ_HOLE_FAIL, 326 }; 327 328 /* 329 * Table of operations for access to a cache. 330 */ 331 struct netfs_cache_ops { 332 /* End an operation */ 333 void (*end_operation)(struct netfs_cache_resources *cres); 334 335 /* Read data from the cache */ 336 int (*read)(struct netfs_cache_resources *cres, 337 loff_t start_pos, 338 struct iov_iter *iter, 339 enum netfs_read_from_hole read_hole, 340 netfs_io_terminated_t term_func, 341 void *term_func_priv); 342 343 /* Write data to the cache */ 344 int (*write)(struct netfs_cache_resources *cres, 345 loff_t start_pos, 346 struct iov_iter *iter, 347 netfs_io_terminated_t term_func, 348 void *term_func_priv); 349 350 /* Write data to the cache from a netfs subrequest. */ 351 void (*issue_write)(struct netfs_io_subrequest *subreq); 352 353 /* Expand readahead request */ 354 void (*expand_readahead)(struct netfs_cache_resources *cres, 355 unsigned long long *_start, 356 unsigned long long *_len, 357 unsigned long long i_size); 358 359 /* Prepare a read operation, shortening it to a cached/uncached 360 * boundary as appropriate. 361 */ 362 enum netfs_io_source (*prepare_read)(struct netfs_io_subrequest *subreq, 363 unsigned long long i_size); 364 365 /* Prepare a write subrequest, working out if we're allowed to do it 366 * and finding out the maximum amount of data to gather before 367 * attempting to submit. If we're not permitted to do it, the 368 * subrequest should be marked failed. 369 */ 370 void (*prepare_write_subreq)(struct netfs_io_subrequest *subreq); 371 372 /* Prepare a write operation, working out what part of the write we can 373 * actually do. 374 */ 375 int (*prepare_write)(struct netfs_cache_resources *cres, 376 loff_t *_start, size_t *_len, size_t upper_len, 377 loff_t i_size, bool no_space_allocated_yet); 378 379 /* Prepare an on-demand read operation, shortening it to a cached/uncached 380 * boundary as appropriate. 381 */ 382 enum netfs_io_source (*prepare_ondemand_read)(struct netfs_cache_resources *cres, 383 loff_t start, size_t *_len, 384 loff_t i_size, 385 unsigned long *_flags, ino_t ino); 386 387 /* Query the occupancy of the cache in a region, returning where the 388 * next chunk of data starts and how long it is. 389 */ 390 int (*query_occupancy)(struct netfs_cache_resources *cres, 391 loff_t start, size_t len, size_t granularity, 392 loff_t *_data_start, size_t *_data_len); 393 }; 394 395 /* High-level read API. */ 396 ssize_t netfs_unbuffered_read_iter_locked(struct kiocb *iocb, struct iov_iter *iter); 397 ssize_t netfs_unbuffered_read_iter(struct kiocb *iocb, struct iov_iter *iter); 398 ssize_t netfs_buffered_read_iter(struct kiocb *iocb, struct iov_iter *iter); 399 ssize_t netfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter); 400 401 /* High-level write API */ 402 ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, 403 struct netfs_group *netfs_group); 404 ssize_t netfs_buffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *from, 405 struct netfs_group *netfs_group); 406 ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from); 407 ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *iter, 408 struct netfs_group *netfs_group); 409 ssize_t netfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from); 410 411 /* Address operations API */ 412 struct readahead_control; 413 void netfs_readahead(struct readahead_control *); 414 int netfs_read_folio(struct file *, struct folio *); 415 int netfs_write_begin(struct netfs_inode *, struct file *, 416 struct address_space *, loff_t pos, unsigned int len, 417 struct folio **, void **fsdata); 418 int netfs_writepages(struct address_space *mapping, 419 struct writeback_control *wbc); 420 bool netfs_dirty_folio(struct address_space *mapping, struct folio *folio); 421 int netfs_unpin_writeback(struct inode *inode, struct writeback_control *wbc); 422 void netfs_clear_inode_writeback(struct inode *inode, const void *aux); 423 void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length); 424 bool netfs_release_folio(struct folio *folio, gfp_t gfp); 425 426 /* VMA operations API. */ 427 vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group); 428 429 /* (Sub)request management API. */ 430 void netfs_read_subreq_progress(struct netfs_io_subrequest *subreq); 431 void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq); 432 void netfs_read_subreq_termination_worker(struct work_struct *work); 433 void netfs_get_subrequest(struct netfs_io_subrequest *subreq, 434 enum netfs_sreq_ref_trace what); 435 void netfs_put_subrequest(struct netfs_io_subrequest *subreq, 436 bool was_async, enum netfs_sreq_ref_trace what); 437 ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, 438 struct iov_iter *new, 439 iov_iter_extraction_t extraction_flags); 440 size_t netfs_limit_iter(const struct iov_iter *iter, size_t start_offset, 441 size_t max_size, size_t max_segs); 442 void netfs_prepare_write_failed(struct netfs_io_subrequest *subreq); 443 void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error, 444 bool was_async); 445 void netfs_queue_write_request(struct netfs_io_subrequest *subreq); 446 447 int netfs_start_io_read(struct inode *inode); 448 void netfs_end_io_read(struct inode *inode); 449 int netfs_start_io_write(struct inode *inode); 450 void netfs_end_io_write(struct inode *inode); 451 int netfs_start_io_direct(struct inode *inode); 452 void netfs_end_io_direct(struct inode *inode); 453 454 /* Miscellaneous APIs. */ 455 struct folio_queue *netfs_folioq_alloc(unsigned int rreq_id, gfp_t gfp, 456 unsigned int trace /*enum netfs_folioq_trace*/); 457 void netfs_folioq_free(struct folio_queue *folioq, 458 unsigned int trace /*enum netfs_trace_folioq*/); 459 460 /** 461 * netfs_inode - Get the netfs inode context from the inode 462 * @inode: The inode to query 463 * 464 * Get the netfs lib inode context from the network filesystem's inode. The 465 * context struct is expected to directly follow on from the VFS inode struct. 466 */ 467 static inline struct netfs_inode *netfs_inode(struct inode *inode) 468 { 469 return container_of(inode, struct netfs_inode, inode); 470 } 471 472 /** 473 * netfs_inode_init - Initialise a netfslib inode context 474 * @ctx: The netfs inode to initialise 475 * @ops: The netfs's operations list 476 * @use_zero_point: True to use the zero_point read optimisation 477 * 478 * Initialise the netfs library context struct. This is expected to follow on 479 * directly from the VFS inode struct. 480 */ 481 static inline void netfs_inode_init(struct netfs_inode *ctx, 482 const struct netfs_request_ops *ops, 483 bool use_zero_point) 484 { 485 ctx->ops = ops; 486 ctx->remote_i_size = i_size_read(&ctx->inode); 487 ctx->zero_point = LLONG_MAX; 488 ctx->flags = 0; 489 atomic_set(&ctx->io_count, 0); 490 #if IS_ENABLED(CONFIG_FSCACHE) 491 ctx->cache = NULL; 492 #endif 493 mutex_init(&ctx->wb_lock); 494 /* ->releasepage() drives zero_point */ 495 if (use_zero_point) { 496 ctx->zero_point = ctx->remote_i_size; 497 mapping_set_release_always(ctx->inode.i_mapping); 498 } 499 } 500 501 /** 502 * netfs_resize_file - Note that a file got resized 503 * @ctx: The netfs inode being resized 504 * @new_i_size: The new file size 505 * @changed_on_server: The change was applied to the server 506 * 507 * Inform the netfs lib that a file got resized so that it can adjust its state. 508 */ 509 static inline void netfs_resize_file(struct netfs_inode *ctx, loff_t new_i_size, 510 bool changed_on_server) 511 { 512 if (changed_on_server) 513 ctx->remote_i_size = new_i_size; 514 if (new_i_size < ctx->zero_point) 515 ctx->zero_point = new_i_size; 516 } 517 518 /** 519 * netfs_i_cookie - Get the cache cookie from the inode 520 * @ctx: The netfs inode to query 521 * 522 * Get the caching cookie (if enabled) from the network filesystem's inode. 523 */ 524 static inline struct fscache_cookie *netfs_i_cookie(struct netfs_inode *ctx) 525 { 526 #if IS_ENABLED(CONFIG_FSCACHE) 527 return ctx->cache; 528 #else 529 return NULL; 530 #endif 531 } 532 533 /** 534 * netfs_wait_for_outstanding_io - Wait for outstanding I/O to complete 535 * @inode: The netfs inode to wait on 536 * 537 * Wait for outstanding I/O requests of any type to complete. This is intended 538 * to be called from inode eviction routines. This makes sure that any 539 * resources held by those requests are cleaned up before we let the inode get 540 * cleaned up. 541 */ 542 static inline void netfs_wait_for_outstanding_io(struct inode *inode) 543 { 544 struct netfs_inode *ictx = netfs_inode(inode); 545 546 wait_var_event(&ictx->io_count, atomic_read(&ictx->io_count) == 0); 547 } 548 549 #endif /* _LINUX_NETFS_H */ 550