/* SPDX-License-Identifier: GPL-2.0-or-later */ /* Network filesystem support services. * * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * See: * * Documentation/filesystems/netfs_library.rst * * for a description of the network filesystem interface declared here. */ #ifndef _LINUX_NETFS_H #define _LINUX_NETFS_H #include #include #include #include enum netfs_sreq_ref_trace; typedef struct mempool_s mempool_t; /** * folio_start_private_2 - Start an fscache write on a folio. [DEPRECATED] * @folio: The folio. * * Call this function before writing a folio to a local cache. Starting a * second write before the first one finishes is not allowed. * * Note that this should no longer be used. */ static inline void folio_start_private_2(struct folio *folio) { VM_BUG_ON_FOLIO(folio_test_private_2(folio), folio); folio_get(folio); folio_set_private_2(folio); } enum netfs_io_source { NETFS_SOURCE_UNKNOWN, NETFS_FILL_WITH_ZEROES, NETFS_DOWNLOAD_FROM_SERVER, NETFS_READ_FROM_CACHE, NETFS_INVALID_READ, NETFS_UPLOAD_TO_SERVER, NETFS_WRITE_TO_CACHE, NETFS_INVALID_WRITE, } __mode(byte); typedef void (*netfs_io_terminated_t)(void *priv, ssize_t transferred_or_error, bool was_async); /* * Per-inode context. This wraps the VFS inode. */ struct netfs_inode { struct inode inode; /* The VFS inode */ const struct netfs_request_ops *ops; #if IS_ENABLED(CONFIG_FSCACHE) struct fscache_cookie *cache; #endif struct mutex wb_lock; /* Writeback serialisation */ loff_t remote_i_size; /* Size of the remote file */ loff_t zero_point; /* Size after which we assume there's no data * on the server */ atomic_t io_count; /* Number of outstanding reqs */ unsigned long flags; #define NETFS_ICTX_ODIRECT 0 /* The file has DIO in progress */ #define NETFS_ICTX_UNBUFFERED 1 /* I/O should not use the pagecache */ #define NETFS_ICTX_WRITETHROUGH 2 /* Write-through caching */ #define NETFS_ICTX_MODIFIED_ATTR 3 /* Indicate change in mtime/ctime */ }; /* * A netfs group - for instance a ceph snap. This is marked on dirty pages and * pages marked with a group must be flushed before they can be written under * the domain of another group. */ struct netfs_group { refcount_t ref; void (*free)(struct netfs_group *netfs_group); }; /* * Information about a dirty page (attached only if necessary). * folio->private */ struct netfs_folio { struct netfs_group *netfs_group; /* Filesystem's grouping marker (or NULL). */ unsigned int dirty_offset; /* Write-streaming dirty data offset */ unsigned int dirty_len; /* Write-streaming dirty data length */ }; #define NETFS_FOLIO_INFO 0x1UL /* OR'd with folio->private. */ #define NETFS_FOLIO_COPY_TO_CACHE ((struct netfs_group *)0x356UL) /* Write to the cache only */ static inline bool netfs_is_folio_info(const void *priv) { return (unsigned long)priv & NETFS_FOLIO_INFO; } static inline struct netfs_folio *__netfs_folio_info(const void *priv) { if (netfs_is_folio_info(priv)) return (struct netfs_folio *)((unsigned long)priv & ~NETFS_FOLIO_INFO); return NULL; } static inline struct netfs_folio *netfs_folio_info(struct folio *folio) { return __netfs_folio_info(folio_get_private(folio)); } static inline struct netfs_group *netfs_folio_group(struct folio *folio) { struct netfs_folio *finfo; void *priv = folio_get_private(folio); finfo = netfs_folio_info(folio); if (finfo) return finfo->netfs_group; return priv; } /* * Stream of I/O subrequests going to a particular destination, such as the * server or the local cache. This is mainly intended for writing where we may * have to write to multiple destinations concurrently. */ struct netfs_io_stream { /* Submission tracking */ struct netfs_io_subrequest *construct; /* Op being constructed */ size_t sreq_max_len; /* Maximum size of a subrequest */ unsigned int sreq_max_segs; /* 0 or max number of segments in an iterator */ unsigned int submit_off; /* Folio offset we're submitting from */ unsigned int submit_len; /* Amount of data left to submit */ unsigned int submit_extendable_to; /* Amount I/O can be rounded up to */ void (*prepare_write)(struct netfs_io_subrequest *subreq); void (*issue_write)(struct netfs_io_subrequest *subreq); /* Collection tracking */ struct list_head subrequests; /* Contributory I/O operations */ struct netfs_io_subrequest *front; /* Op being collected */ unsigned long long collected_to; /* Position we've collected results to */ size_t transferred; /* The amount transferred from this stream */ enum netfs_io_source source; /* Where to read from/write to */ unsigned short error; /* Aggregate error for the stream */ unsigned char stream_nr; /* Index of stream in parent table */ bool avail; /* T if stream is available */ bool active; /* T if stream is active */ bool need_retry; /* T if this stream needs retrying */ bool failed; /* T if this stream failed */ }; /* * Resources required to do operations on a cache. */ struct netfs_cache_resources { const struct netfs_cache_ops *ops; void *cache_priv; void *cache_priv2; unsigned int debug_id; /* Cookie debug ID */ unsigned int inval_counter; /* object->inval_counter at begin_op */ }; /* * Descriptor for a single component subrequest. Each operation represents an * individual read/write from/to a server, a cache, a journal, etc.. * * The buffer iterator is persistent for the life of the subrequest struct and * the pages it points to can be relied on to exist for the duration. */ struct netfs_io_subrequest { struct netfs_io_request *rreq; /* Supervising I/O request */ struct work_struct work; struct list_head rreq_link; /* Link in rreq->subrequests */ struct iov_iter io_iter; /* Iterator for this subrequest */ unsigned long long start; /* Where to start the I/O */ size_t len; /* Size of the I/O */ size_t transferred; /* Amount of data transferred */ size_t consumed; /* Amount of read data consumed */ size_t prev_donated; /* Amount of data donated from previous subreq */ size_t next_donated; /* Amount of data donated from next subreq */ refcount_t ref; short error; /* 0 or error that occurred */ unsigned short debug_index; /* Index in list (for debugging output) */ unsigned int nr_segs; /* Number of segs in io_iter */ enum netfs_io_source source; /* Where to read from/write to */ unsigned char stream_nr; /* I/O stream this belongs to */ unsigned char curr_folioq_slot; /* Folio currently being read */ unsigned char curr_folio_order; /* Order of folio */ struct folio_queue *curr_folioq; /* Queue segment in which current folio resides */ unsigned long flags; #define NETFS_SREQ_COPY_TO_CACHE 0 /* Set if should copy the data to the cache */ #define NETFS_SREQ_CLEAR_TAIL 1 /* Set if the rest of the read should be cleared */ #define NETFS_SREQ_SEEK_DATA_READ 3 /* Set if ->read() should SEEK_DATA first */ #define NETFS_SREQ_NO_PROGRESS 4 /* Set if we didn't manage to read any data */ #define NETFS_SREQ_ONDEMAND 5 /* Set if it's from on-demand read mode */ #define NETFS_SREQ_BOUNDARY 6 /* Set if ends on hard boundary (eg. ceph object) */ #define NETFS_SREQ_HIT_EOF 7 /* Set if short due to EOF */ #define NETFS_SREQ_IN_PROGRESS 8 /* Unlocked when the subrequest completes */ #define NETFS_SREQ_NEED_RETRY 9 /* Set if the filesystem requests a retry */ #define NETFS_SREQ_RETRYING 10 /* Set if we're retrying */ #define NETFS_SREQ_FAILED 11 /* Set if the subreq failed unretryably */ }; enum netfs_io_origin { NETFS_READAHEAD, /* This read was triggered by readahead */ NETFS_READPAGE, /* This read is a synchronous read */ NETFS_READ_GAPS, /* This read is a synchronous read to fill gaps */ NETFS_READ_FOR_WRITE, /* This read is to prepare a write */ NETFS_DIO_READ, /* This is a direct I/O read */ NETFS_WRITEBACK, /* This write was triggered by writepages */ NETFS_WRITETHROUGH, /* This write was made by netfs_perform_write() */ NETFS_UNBUFFERED_WRITE, /* This is an unbuffered write */ NETFS_DIO_WRITE, /* This is a direct I/O write */ NETFS_PGPRIV2_COPY_TO_CACHE, /* [DEPRECATED] This is writing read data to the cache */ nr__netfs_io_origin } __mode(byte); /* * Descriptor for an I/O helper request. This is used to make multiple I/O * operations to a variety of data stores and then stitch the result together. */ struct netfs_io_request { union { struct work_struct work; struct rcu_head rcu; }; struct inode *inode; /* The file being accessed */ struct address_space *mapping; /* The mapping being accessed */ struct kiocb *iocb; /* AIO completion vector */ struct netfs_cache_resources cache_resources; struct readahead_control *ractl; /* Readahead descriptor */ struct list_head proc_link; /* Link in netfs_iorequests */ struct list_head subrequests; /* Contributory I/O operations */ struct netfs_io_stream io_streams[2]; /* Streams of parallel I/O operations */ #define NR_IO_STREAMS 2 //wreq->nr_io_streams struct netfs_group *group; /* Writeback group being written back */ struct folio_queue *buffer; /* Head of I/O buffer */ struct folio_queue *buffer_tail; /* Tail of I/O buffer */ struct iov_iter iter; /* Unencrypted-side iterator */ struct iov_iter io_iter; /* I/O (Encrypted-side) iterator */ void *netfs_priv; /* Private data for the netfs */ void *netfs_priv2; /* Private data for the netfs */ struct bio_vec *direct_bv; /* DIO buffer list (when handling iovec-iter) */ unsigned int direct_bv_count; /* Number of elements in direct_bv[] */ unsigned int debug_id; unsigned int rsize; /* Maximum read size (0 for none) */ unsigned int wsize; /* Maximum write size (0 for none) */ atomic_t subreq_counter; /* Next subreq->debug_index */ unsigned int nr_group_rel; /* Number of refs to release on ->group */ spinlock_t lock; /* Lock for queuing subreqs */ atomic_t nr_outstanding; /* Number of ops in progress */ unsigned long long submitted; /* Amount submitted for I/O so far */ unsigned long long len; /* Length of the request */ size_t transferred; /* Amount to be indicated as transferred */ long error; /* 0 or error that occurred */ enum netfs_io_origin origin; /* Origin of the request */ bool direct_bv_unpin; /* T if direct_bv[] must be unpinned */ u8 buffer_head_slot; /* First slot in ->buffer */ u8 buffer_tail_slot; /* Next slot in ->buffer_tail */ unsigned long long i_size; /* Size of the file */ unsigned long long start; /* Start position */ atomic64_t issued_to; /* Write issuer folio cursor */ unsigned long long collected_to; /* Point we've collected to */ unsigned long long cleaned_to; /* Position we've cleaned folios to */ pgoff_t no_unlock_folio; /* Don't unlock this folio after read */ size_t prev_donated; /* Fallback for subreq->prev_donated */ refcount_t ref; unsigned long flags; #define NETFS_RREQ_COPY_TO_CACHE 1 /* Need to write to the cache */ #define NETFS_RREQ_NO_UNLOCK_FOLIO 2 /* Don't unlock no_unlock_folio on completion */ #define NETFS_RREQ_DONT_UNLOCK_FOLIOS 3 /* Don't unlock the folios on completion */ #define NETFS_RREQ_FAILED 4 /* The request failed */ #define NETFS_RREQ_IN_PROGRESS 5 /* Unlocked when the request completes */ #define NETFS_RREQ_UPLOAD_TO_SERVER 8 /* Need to write to the server */ #define NETFS_RREQ_NONBLOCK 9 /* Don't block if possible (O_NONBLOCK) */ #define NETFS_RREQ_BLOCKED 10 /* We blocked */ #define NETFS_RREQ_PAUSE 11 /* Pause subrequest generation */ #define NETFS_RREQ_USE_IO_ITER 12 /* Use ->io_iter rather than ->i_pages */ #define NETFS_RREQ_ALL_QUEUED 13 /* All subreqs are now queued */ #define NETFS_RREQ_NEED_RETRY 14 /* Need to try retrying */ #define NETFS_RREQ_USE_PGPRIV2 31 /* [DEPRECATED] Use PG_private_2 to mark * write to cache on read */ const struct netfs_request_ops *netfs_ops; void (*cleanup)(struct netfs_io_request *req); }; /* * Operations the network filesystem can/must provide to the helpers. */ struct netfs_request_ops { mempool_t *request_pool; mempool_t *subrequest_pool; int (*init_request)(struct netfs_io_request *rreq, struct file *file); void (*free_request)(struct netfs_io_request *rreq); void (*free_subrequest)(struct netfs_io_subrequest *rreq); /* Read request handling */ void (*expand_readahead)(struct netfs_io_request *rreq); int (*prepare_read)(struct netfs_io_subrequest *subreq); void (*issue_read)(struct netfs_io_subrequest *subreq); bool (*is_still_valid)(struct netfs_io_request *rreq); int (*check_write_begin)(struct file *file, loff_t pos, unsigned len, struct folio **foliop, void **_fsdata); void (*done)(struct netfs_io_request *rreq); /* Modification handling */ void (*update_i_size)(struct inode *inode, loff_t i_size); void (*post_modify)(struct inode *inode); /* Write request handling */ void (*begin_writeback)(struct netfs_io_request *wreq); void (*prepare_write)(struct netfs_io_subrequest *subreq); void (*issue_write)(struct netfs_io_subrequest *subreq); void (*retry_request)(struct netfs_io_request *wreq, struct netfs_io_stream *stream); void (*invalidate_cache)(struct netfs_io_request *wreq); }; /* * How to handle reading from a hole. */ enum netfs_read_from_hole { NETFS_READ_HOLE_IGNORE, NETFS_READ_HOLE_CLEAR, NETFS_READ_HOLE_FAIL, }; /* * Table of operations for access to a cache. */ struct netfs_cache_ops { /* End an operation */ void (*end_operation)(struct netfs_cache_resources *cres); /* Read data from the cache */ int (*read)(struct netfs_cache_resources *cres, loff_t start_pos, struct iov_iter *iter, enum netfs_read_from_hole read_hole, netfs_io_terminated_t term_func, void *term_func_priv); /* Write data to the cache */ int (*write)(struct netfs_cache_resources *cres, loff_t start_pos, struct iov_iter *iter, netfs_io_terminated_t term_func, void *term_func_priv); /* Write data to the cache from a netfs subrequest. */ void (*issue_write)(struct netfs_io_subrequest *subreq); /* Expand readahead request */ void (*expand_readahead)(struct netfs_cache_resources *cres, unsigned long long *_start, unsigned long long *_len, unsigned long long i_size); /* Prepare a read operation, shortening it to a cached/uncached * boundary as appropriate. */ enum netfs_io_source (*prepare_read)(struct netfs_io_subrequest *subreq, unsigned long long i_size); /* Prepare a write subrequest, working out if we're allowed to do it * and finding out the maximum amount of data to gather before * attempting to submit. If we're not permitted to do it, the * subrequest should be marked failed. */ void (*prepare_write_subreq)(struct netfs_io_subrequest *subreq); /* Prepare a write operation, working out what part of the write we can * actually do. */ int (*prepare_write)(struct netfs_cache_resources *cres, loff_t *_start, size_t *_len, size_t upper_len, loff_t i_size, bool no_space_allocated_yet); /* Prepare an on-demand read operation, shortening it to a cached/uncached * boundary as appropriate. */ enum netfs_io_source (*prepare_ondemand_read)(struct netfs_cache_resources *cres, loff_t start, size_t *_len, loff_t i_size, unsigned long *_flags, ino_t ino); /* Query the occupancy of the cache in a region, returning where the * next chunk of data starts and how long it is. */ int (*query_occupancy)(struct netfs_cache_resources *cres, loff_t start, size_t len, size_t granularity, loff_t *_data_start, size_t *_data_len); }; /* High-level read API. */ ssize_t netfs_unbuffered_read_iter_locked(struct kiocb *iocb, struct iov_iter *iter); ssize_t netfs_unbuffered_read_iter(struct kiocb *iocb, struct iov_iter *iter); ssize_t netfs_buffered_read_iter(struct kiocb *iocb, struct iov_iter *iter); ssize_t netfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter); /* High-level write API */ ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter, struct netfs_group *netfs_group); ssize_t netfs_buffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *from, struct netfs_group *netfs_group); ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from); ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *iter, struct netfs_group *netfs_group); ssize_t netfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from); /* Address operations API */ struct readahead_control; void netfs_readahead(struct readahead_control *); int netfs_read_folio(struct file *, struct folio *); int netfs_write_begin(struct netfs_inode *, struct file *, struct address_space *, loff_t pos, unsigned int len, struct folio **, void **fsdata); int netfs_writepages(struct address_space *mapping, struct writeback_control *wbc); bool netfs_dirty_folio(struct address_space *mapping, struct folio *folio); int netfs_unpin_writeback(struct inode *inode, struct writeback_control *wbc); void netfs_clear_inode_writeback(struct inode *inode, const void *aux); void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length); bool netfs_release_folio(struct folio *folio, gfp_t gfp); /* VMA operations API. */ vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group); /* (Sub)request management API. */ void netfs_read_subreq_progress(struct netfs_io_subrequest *subreq, bool was_async); void netfs_read_subreq_terminated(struct netfs_io_subrequest *subreq, int error, bool was_async); void netfs_get_subrequest(struct netfs_io_subrequest *subreq, enum netfs_sreq_ref_trace what); void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async, enum netfs_sreq_ref_trace what); ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, struct iov_iter *new, iov_iter_extraction_t extraction_flags); size_t netfs_limit_iter(const struct iov_iter *iter, size_t start_offset, size_t max_size, size_t max_segs); void netfs_prepare_write_failed(struct netfs_io_subrequest *subreq); void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error, bool was_async); void netfs_queue_write_request(struct netfs_io_subrequest *subreq); int netfs_start_io_read(struct inode *inode); void netfs_end_io_read(struct inode *inode); int netfs_start_io_write(struct inode *inode); void netfs_end_io_write(struct inode *inode); int netfs_start_io_direct(struct inode *inode); void netfs_end_io_direct(struct inode *inode); /** * netfs_inode - Get the netfs inode context from the inode * @inode: The inode to query * * Get the netfs lib inode context from the network filesystem's inode. The * context struct is expected to directly follow on from the VFS inode struct. */ static inline struct netfs_inode *netfs_inode(struct inode *inode) { return container_of(inode, struct netfs_inode, inode); } /** * netfs_inode_init - Initialise a netfslib inode context * @ctx: The netfs inode to initialise * @ops: The netfs's operations list * @use_zero_point: True to use the zero_point read optimisation * * Initialise the netfs library context struct. This is expected to follow on * directly from the VFS inode struct. */ static inline void netfs_inode_init(struct netfs_inode *ctx, const struct netfs_request_ops *ops, bool use_zero_point) { ctx->ops = ops; ctx->remote_i_size = i_size_read(&ctx->inode); ctx->zero_point = LLONG_MAX; ctx->flags = 0; atomic_set(&ctx->io_count, 0); #if IS_ENABLED(CONFIG_FSCACHE) ctx->cache = NULL; #endif mutex_init(&ctx->wb_lock); /* ->releasepage() drives zero_point */ if (use_zero_point) { ctx->zero_point = ctx->remote_i_size; mapping_set_release_always(ctx->inode.i_mapping); } } /** * netfs_resize_file - Note that a file got resized * @ctx: The netfs inode being resized * @new_i_size: The new file size * @changed_on_server: The change was applied to the server * * Inform the netfs lib that a file got resized so that it can adjust its state. */ static inline void netfs_resize_file(struct netfs_inode *ctx, loff_t new_i_size, bool changed_on_server) { if (changed_on_server) ctx->remote_i_size = new_i_size; if (new_i_size < ctx->zero_point) ctx->zero_point = new_i_size; } /** * netfs_i_cookie - Get the cache cookie from the inode * @ctx: The netfs inode to query * * Get the caching cookie (if enabled) from the network filesystem's inode. */ static inline struct fscache_cookie *netfs_i_cookie(struct netfs_inode *ctx) { #if IS_ENABLED(CONFIG_FSCACHE) return ctx->cache; #else return NULL; #endif } /** * netfs_wait_for_outstanding_io - Wait for outstanding I/O to complete * @inode: The netfs inode to wait on * * Wait for outstanding I/O requests of any type to complete. This is intended * to be called from inode eviction routines. This makes sure that any * resources held by those requests are cleaned up before we let the inode get * cleaned up. */ static inline void netfs_wait_for_outstanding_io(struct inode *inode) { struct netfs_inode *ictx = netfs_inode(inode); wait_var_event(&ictx->io_count, atomic_read(&ictx->io_count) == 0); } #endif /* _LINUX_NETFS_H */