// SPDX-License-Identifier: GPL-2.0-only /* * linux/fs/nfs/pagelist.c * * A set of helper functions for managing NFS read and write requests. * The main purpose of these routines is to provide support for the * coalescing of several requests into a single RPC call. * * Copyright 2000, 2001 (c) Trond Myklebust <trond.myklebust@fys.uio.no> * */ #include <linux/slab.h> #include <linux/file.h> #include <linux/sched.h> #include <linux/sunrpc/clnt.h> #include <linux/nfs.h> #include <linux/nfs3.h> #include <linux/nfs4.h> #include <linux/nfs_fs.h> #include <linux/nfs_page.h> #include <linux/nfs_mount.h> #include <linux/export.h> #include "internal.h" #include "pnfs.h" #include "nfstrace.h" #define NFSDBG_FACILITY NFSDBG_PAGECACHE static struct kmem_cache *nfs_page_cachep; static const struct rpc_call_ops nfs_pgio_common_ops; struct nfs_pgio_mirror * nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc) { return &desc->pg_mirrors[desc->pg_mirror_idx]; } EXPORT_SYMBOL_GPL(nfs_pgio_current_mirror); void nfs_pgheader_init(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr, void (*release)(struct nfs_pgio_header *hdr)) { struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); hdr->req = nfs_list_entry(mirror->pg_list.next); hdr->inode = desc->pg_inode; hdr->cred = nfs_req_openctx(hdr->req)->cred; hdr->io_start = req_offset(hdr->req); hdr->good_bytes = mirror->pg_count; hdr->io_completion = desc->pg_io_completion; hdr->dreq = desc->pg_dreq; hdr->release = release; hdr->completion_ops = desc->pg_completion_ops; if (hdr->completion_ops->init_hdr) hdr->completion_ops->init_hdr(hdr); hdr->pgio_mirror_idx = desc->pg_mirror_idx; } EXPORT_SYMBOL_GPL(nfs_pgheader_init); void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos) { unsigned int new = pos - hdr->io_start; trace_nfs_pgio_error(hdr, error, pos); if (hdr->good_bytes > new) { hdr->good_bytes = new; clear_bit(NFS_IOHDR_EOF, &hdr->flags); if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags)) hdr->error = error; } } static inline struct nfs_page * nfs_page_alloc(void) { struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_KERNEL); if (p) INIT_LIST_HEAD(&p->wb_list); return p; } static inline void nfs_page_free(struct nfs_page *p) { kmem_cache_free(nfs_page_cachep, p); } /** * nfs_iocounter_wait - wait for i/o to complete * @l_ctx: nfs_lock_context with io_counter to use * * returns -ERESTARTSYS if interrupted by a fatal signal. * Otherwise returns 0 once the io_count hits 0. */ int nfs_iocounter_wait(struct nfs_lock_context *l_ctx) { return wait_var_event_killable(&l_ctx->io_count, !atomic_read(&l_ctx->io_count)); } /** * nfs_async_iocounter_wait - wait on a rpc_waitqueue for I/O * to complete * @task: the rpc_task that should wait * @l_ctx: nfs_lock_context with io_counter to check * * Returns true if there is outstanding I/O to wait on and the * task has been put to sleep. */ bool nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx) { struct inode *inode = d_inode(l_ctx->open_context->dentry); bool ret = false; if (atomic_read(&l_ctx->io_count) > 0) { rpc_sleep_on(&NFS_SERVER(inode)->uoc_rpcwaitq, task, NULL); ret = true; } if (atomic_read(&l_ctx->io_count) == 0) { rpc_wake_up_queued_task(&NFS_SERVER(inode)->uoc_rpcwaitq, task); ret = false; } return ret; } EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait); /* * nfs_page_lock_head_request - page lock the head of the page group * @req: any member of the page group */ struct nfs_page * nfs_page_group_lock_head(struct nfs_page *req) { struct nfs_page *head = req->wb_head; while (!nfs_lock_request(head)) { int ret = nfs_wait_on_request(head); if (ret < 0) return ERR_PTR(ret); } if (head != req) kref_get(&head->wb_kref); return head; } /* * nfs_unroll_locks - unlock all newly locked reqs and wait on @req * @head: head request of page group, must be holding head lock * @req: request that couldn't lock and needs to wait on the req bit lock * * This is a helper function for nfs_lock_and_join_requests * returns 0 on success, < 0 on error. */ static void nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req) { struct nfs_page *tmp; /* relinquish all the locks successfully grabbed this run */ for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) { if (!kref_read(&tmp->wb_kref)) continue; nfs_unlock_and_release_request(tmp); } } /* * nfs_page_group_lock_subreq - try to lock a subrequest * @head: head request of page group * @subreq: request to lock * * This is a helper function for nfs_lock_and_join_requests which * must be called with the head request and page group both locked. * On error, it returns with the page group unlocked. */ static int nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq) { int ret; if (!kref_get_unless_zero(&subreq->wb_kref)) return 0; while (!nfs_lock_request(subreq)) { nfs_page_group_unlock(head); ret = nfs_wait_on_request(subreq); if (!ret) ret = nfs_page_group_lock(head); if (ret < 0) { nfs_unroll_locks(head, subreq); nfs_release_request(subreq); return ret; } } return 0; } /* * nfs_page_group_lock_subrequests - try to lock the subrequests * @head: head request of page group * * This is a helper function for nfs_lock_and_join_requests which * must be called with the head request locked. */ int nfs_page_group_lock_subrequests(struct nfs_page *head) { struct nfs_page *subreq; int ret; ret = nfs_page_group_lock(head); if (ret < 0) return ret; /* lock each request in the page group */ for (subreq = head->wb_this_page; subreq != head; subreq = subreq->wb_this_page) { ret = nfs_page_group_lock_subreq(head, subreq); if (ret < 0) return ret; } nfs_page_group_unlock(head); return 0; } /* * nfs_page_set_headlock - set the request PG_HEADLOCK * @req: request that is to be locked * * this lock must be held when modifying req->wb_head * * return 0 on success, < 0 on error */ int nfs_page_set_headlock(struct nfs_page *req) { if (!test_and_set_bit(PG_HEADLOCK, &req->wb_flags)) return 0; set_bit(PG_CONTENDED1, &req->wb_flags); smp_mb__after_atomic(); return wait_on_bit_lock(&req->wb_flags, PG_HEADLOCK, TASK_UNINTERRUPTIBLE); } /* * nfs_page_clear_headlock - clear the request PG_HEADLOCK * @req: request that is to be locked */ void nfs_page_clear_headlock(struct nfs_page *req) { smp_mb__before_atomic(); clear_bit(PG_HEADLOCK, &req->wb_flags); smp_mb__after_atomic(); if (!test_bit(PG_CONTENDED1, &req->wb_flags)) return; wake_up_bit(&req->wb_flags, PG_HEADLOCK); } /* * nfs_page_group_lock - lock the head of the page group * @req: request in group that is to be locked * * this lock must be held when traversing or modifying the page * group list * * return 0 on success, < 0 on error */ int nfs_page_group_lock(struct nfs_page *req) { int ret; ret = nfs_page_set_headlock(req); if (ret || req->wb_head == req) return ret; return nfs_page_set_headlock(req->wb_head); } /* * nfs_page_group_unlock - unlock the head of the page group * @req: request in group that is to be unlocked */ void nfs_page_group_unlock(struct nfs_page *req) { if (req != req->wb_head) nfs_page_clear_headlock(req->wb_head); nfs_page_clear_headlock(req); } /* * nfs_page_group_sync_on_bit_locked * * must be called with page group lock held */ static bool nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit) { struct nfs_page *head = req->wb_head; struct nfs_page *tmp; WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags)); WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags)); tmp = req->wb_this_page; while (tmp != req) { if (!test_bit(bit, &tmp->wb_flags)) return false; tmp = tmp->wb_this_page; } /* true! reset all bits */ tmp = req; do { clear_bit(bit, &tmp->wb_flags); tmp = tmp->wb_this_page; } while (tmp != req); return true; } /* * nfs_page_group_sync_on_bit - set bit on current request, but only * return true if the bit is set for all requests in page group * @req - request in page group * @bit - PG_* bit that is used to sync page group */ bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit) { bool ret; nfs_page_group_lock(req); ret = nfs_page_group_sync_on_bit_locked(req, bit); nfs_page_group_unlock(req); return ret; } /* * nfs_page_group_init - Initialize the page group linkage for @req * @req - a new nfs request * @prev - the previous request in page group, or NULL if @req is the first * or only request in the group (the head). */ static inline void nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev) { struct inode *inode; WARN_ON_ONCE(prev == req); if (!prev) { /* a head request */ req->wb_head = req; req->wb_this_page = req; } else { /* a subrequest */ WARN_ON_ONCE(prev->wb_this_page != prev->wb_head); WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags)); req->wb_head = prev->wb_head; req->wb_this_page = prev->wb_this_page; prev->wb_this_page = req; /* All subrequests take a ref on the head request until * nfs_page_group_destroy is called */ kref_get(&req->wb_head->wb_kref); /* grab extra ref and bump the request count if head request * has extra ref from the write/commit path to handle handoff * between write and commit lists. */ if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) { inode = page_file_mapping(req->wb_page)->host; set_bit(PG_INODE_REF, &req->wb_flags); kref_get(&req->wb_kref); atomic_long_inc(&NFS_I(inode)->nrequests); } } } /* * nfs_page_group_destroy - sync the destruction of page groups * @req - request that no longer needs the page group * * releases the page group reference from each member once all * members have called this function. */ static void nfs_page_group_destroy(struct kref *kref) { struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref); struct nfs_page *head = req->wb_head; struct nfs_page *tmp, *next; if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN)) goto out; tmp = req; do { next = tmp->wb_this_page; /* unlink and free */ tmp->wb_this_page = tmp; tmp->wb_head = tmp; nfs_free_request(tmp); tmp = next; } while (tmp != req); out: /* subrequests must release the ref on the head request */ if (head != req) nfs_release_request(head); } static struct nfs_page * __nfs_create_request(struct nfs_lock_context *l_ctx, struct page *page, unsigned int pgbase, unsigned int offset, unsigned int count) { struct nfs_page *req; struct nfs_open_context *ctx = l_ctx->open_context; if (test_bit(NFS_CONTEXT_BAD, &ctx->flags)) return ERR_PTR(-EBADF); /* try to allocate the request struct */ req = nfs_page_alloc(); if (req == NULL) return ERR_PTR(-ENOMEM); req->wb_lock_context = l_ctx; refcount_inc(&l_ctx->count); atomic_inc(&l_ctx->io_count); /* Initialize the request struct. Initially, we assume a * long write-back delay. This will be adjusted in * update_nfs_request below if the region is not locked. */ req->wb_page = page; if (page) { req->wb_index = page_index(page); get_page(page); } req->wb_offset = offset; req->wb_pgbase = pgbase; req->wb_bytes = count; kref_init(&req->wb_kref); req->wb_nio = 0; return req; } /** * nfs_create_request - Create an NFS read/write request. * @ctx: open context to use * @page: page to write * @offset: starting offset within the page for the write * @count: number of bytes to read/write * * The page must be locked by the caller. This makes sure we never * create two different requests for the same page. * User should ensure it is safe to sleep in this function. */ struct nfs_page * nfs_create_request(struct nfs_open_context *ctx, struct page *page, unsigned int offset, unsigned int count) { struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx); struct nfs_page *ret; if (IS_ERR(l_ctx)) return ERR_CAST(l_ctx); ret = __nfs_create_request(l_ctx, page, offset, offset, count); if (!IS_ERR(ret)) nfs_page_group_init(ret, NULL); nfs_put_lock_context(l_ctx); return ret; } static struct nfs_page * nfs_create_subreq(struct nfs_page *req, unsigned int pgbase, unsigned int offset, unsigned int count) { struct nfs_page *last; struct nfs_page *ret; ret = __nfs_create_request(req->wb_lock_context, req->wb_page, pgbase, offset, count); if (!IS_ERR(ret)) { /* find the last request */ for (last = req->wb_head; last->wb_this_page != req->wb_head; last = last->wb_this_page) ; nfs_lock_request(ret); ret->wb_index = req->wb_index; nfs_page_group_init(ret, last); ret->wb_nio = req->wb_nio; } return ret; } /** * nfs_unlock_request - Unlock request and wake up sleepers. * @req: pointer to request */ void nfs_unlock_request(struct nfs_page *req) { if (!NFS_WBACK_BUSY(req)) { printk(KERN_ERR "NFS: Invalid unlock attempted\n"); BUG(); } smp_mb__before_atomic(); clear_bit(PG_BUSY, &req->wb_flags); smp_mb__after_atomic(); if (!test_bit(PG_CONTENDED2, &req->wb_flags)) return; wake_up_bit(&req->wb_flags, PG_BUSY); } /** * nfs_unlock_and_release_request - Unlock request and release the nfs_page * @req: pointer to request */ void nfs_unlock_and_release_request(struct nfs_page *req) { nfs_unlock_request(req); nfs_release_request(req); } /* * nfs_clear_request - Free up all resources allocated to the request * @req: * * Release page and open context resources associated with a read/write * request after it has completed. */ static void nfs_clear_request(struct nfs_page *req) { struct page *page = req->wb_page; struct nfs_lock_context *l_ctx = req->wb_lock_context; struct nfs_open_context *ctx; if (page != NULL) { put_page(page); req->wb_page = NULL; } if (l_ctx != NULL) { if (atomic_dec_and_test(&l_ctx->io_count)) { wake_up_var(&l_ctx->io_count); ctx = l_ctx->open_context; if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags)) rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq); } nfs_put_lock_context(l_ctx); req->wb_lock_context = NULL; } } /** * nfs_release_request - Release the count on an NFS read/write request * @req: request to release * * Note: Should never be called with the spinlock held! */ void nfs_free_request(struct nfs_page *req) { WARN_ON_ONCE(req->wb_this_page != req); /* extra debug: make sure no sync bits are still set */ WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags)); WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags)); WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags)); WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags)); WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags)); /* Release struct file and open context */ nfs_clear_request(req); nfs_page_free(req); } void nfs_release_request(struct nfs_page *req) { kref_put(&req->wb_kref, nfs_page_group_destroy); } EXPORT_SYMBOL_GPL(nfs_release_request); /** * nfs_wait_on_request - Wait for a request to complete. * @req: request to wait upon. * * Interruptible by fatal signals only. * The user is responsible for holding a count on the request. */ int nfs_wait_on_request(struct nfs_page *req) { if (!test_bit(PG_BUSY, &req->wb_flags)) return 0; set_bit(PG_CONTENDED2, &req->wb_flags); smp_mb__after_atomic(); return wait_on_bit_io(&req->wb_flags, PG_BUSY, TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL_GPL(nfs_wait_on_request); /* * nfs_generic_pg_test - determine if requests can be coalesced * @desc: pointer to descriptor * @prev: previous request in desc, or NULL * @req: this request * * Returns zero if @req cannot be coalesced into @desc, otherwise it returns * the size of the request. */ size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, struct nfs_page *prev, struct nfs_page *req) { struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); if (mirror->pg_count > mirror->pg_bsize) { /* should never happen */ WARN_ON_ONCE(1); return 0; } /* * Limit the request size so that we can still allocate a page array * for it without upsetting the slab allocator. */ if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) * sizeof(struct page *) > PAGE_SIZE) return 0; return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes); } EXPORT_SYMBOL_GPL(nfs_generic_pg_test); struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops) { struct nfs_pgio_header *hdr = ops->rw_alloc_header(); if (hdr) { INIT_LIST_HEAD(&hdr->pages); hdr->rw_ops = ops; } return hdr; } EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc); /** * nfs_pgio_data_destroy - make @hdr suitable for reuse * * Frees memory and releases refs from nfs_generic_pgio, so that it may * be called again. * * @hdr: A header that has had nfs_generic_pgio called */ static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr) { if (hdr->args.context) put_nfs_open_context(hdr->args.context); if (hdr->page_array.pagevec != hdr->page_array.page_array) kfree(hdr->page_array.pagevec); } /* * nfs_pgio_header_free - Free a read or write header * @hdr: The header to free */ void nfs_pgio_header_free(struct nfs_pgio_header *hdr) { nfs_pgio_data_destroy(hdr); hdr->rw_ops->rw_free_header(hdr); } EXPORT_SYMBOL_GPL(nfs_pgio_header_free); /** * nfs_pgio_rpcsetup - Set up arguments for a pageio call * @hdr: The pageio hdr * @count: Number of bytes to read * @how: How to commit data (writes only) * @cinfo: Commit information for the call (writes only) */ static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr, unsigned int count, int how, struct nfs_commit_info *cinfo) { struct nfs_page *req = hdr->req; /* Set up the RPC argument and reply structs * NB: take care not to mess about with hdr->commit et al. */ hdr->args.fh = NFS_FH(hdr->inode); hdr->args.offset = req_offset(req); /* pnfs_set_layoutcommit needs this */ hdr->mds_offset = hdr->args.offset; hdr->args.pgbase = req->wb_pgbase; hdr->args.pages = hdr->page_array.pagevec; hdr->args.count = count; hdr->args.context = get_nfs_open_context(nfs_req_openctx(req)); hdr->args.lock_context = req->wb_lock_context; hdr->args.stable = NFS_UNSTABLE; switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) { case 0: break; case FLUSH_COND_STABLE: if (nfs_reqs_to_commit(cinfo)) break; /* fall through */ default: hdr->args.stable = NFS_FILE_SYNC; } hdr->res.fattr = &hdr->fattr; hdr->res.count = 0; hdr->res.eof = 0; hdr->res.verf = &hdr->verf; nfs_fattr_init(&hdr->fattr); } /** * nfs_pgio_prepare - Prepare pageio hdr to go over the wire * @task: The current task * @calldata: pageio header to prepare */ static void nfs_pgio_prepare(struct rpc_task *task, void *calldata) { struct nfs_pgio_header *hdr = calldata; int err; err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr); if (err) rpc_exit(task, err); } int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr, const struct cred *cred, const struct nfs_rpc_ops *rpc_ops, const struct rpc_call_ops *call_ops, int how, int flags) { struct rpc_task *task; struct rpc_message msg = { .rpc_argp = &hdr->args, .rpc_resp = &hdr->res, .rpc_cred = cred, }; struct rpc_task_setup task_setup_data = { .rpc_client = clnt, .task = &hdr->task, .rpc_message = &msg, .callback_ops = call_ops, .callback_data = hdr, .workqueue = nfsiod_workqueue, .flags = RPC_TASK_ASYNC | flags, }; hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how); dprintk("NFS: initiated pgio call " "(req %s/%llu, %u bytes @ offset %llu)\n", hdr->inode->i_sb->s_id, (unsigned long long)NFS_FILEID(hdr->inode), hdr->args.count, (unsigned long long)hdr->args.offset); task = rpc_run_task(&task_setup_data); if (IS_ERR(task)) return PTR_ERR(task); rpc_put_task(task); return 0; } EXPORT_SYMBOL_GPL(nfs_initiate_pgio); /** * nfs_pgio_error - Clean up from a pageio error * @hdr: pageio header */ static void nfs_pgio_error(struct nfs_pgio_header *hdr) { set_bit(NFS_IOHDR_REDO, &hdr->flags); hdr->completion_ops->completion(hdr); } /** * nfs_pgio_release - Release pageio data * @calldata: The pageio header to release */ static void nfs_pgio_release(void *calldata) { struct nfs_pgio_header *hdr = calldata; hdr->completion_ops->completion(hdr); } static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror, unsigned int bsize) { INIT_LIST_HEAD(&mirror->pg_list); mirror->pg_bytes_written = 0; mirror->pg_count = 0; mirror->pg_bsize = bsize; mirror->pg_base = 0; mirror->pg_recoalesce = 0; } /** * nfs_pageio_init - initialise a page io descriptor * @desc: pointer to descriptor * @inode: pointer to inode * @pg_ops: pointer to pageio operations * @compl_ops: pointer to pageio completion operations * @rw_ops: pointer to nfs read/write operations * @bsize: io block size * @io_flags: extra parameters for the io function */ void nfs_pageio_init(struct nfs_pageio_descriptor *desc, struct inode *inode, const struct nfs_pageio_ops *pg_ops, const struct nfs_pgio_completion_ops *compl_ops, const struct nfs_rw_ops *rw_ops, size_t bsize, int io_flags) { desc->pg_moreio = 0; desc->pg_inode = inode; desc->pg_ops = pg_ops; desc->pg_completion_ops = compl_ops; desc->pg_rw_ops = rw_ops; desc->pg_ioflags = io_flags; desc->pg_error = 0; desc->pg_lseg = NULL; desc->pg_io_completion = NULL; desc->pg_dreq = NULL; desc->pg_bsize = bsize; desc->pg_mirror_count = 1; desc->pg_mirror_idx = 0; desc->pg_mirrors_dynamic = NULL; desc->pg_mirrors = desc->pg_mirrors_static; nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize); desc->pg_maxretrans = 0; } /** * nfs_pgio_result - Basic pageio error handling * @task: The task that ran * @calldata: Pageio header to check */ static void nfs_pgio_result(struct rpc_task *task, void *calldata) { struct nfs_pgio_header *hdr = calldata; struct inode *inode = hdr->inode; dprintk("NFS: %s: %5u, (status %d)\n", __func__, task->tk_pid, task->tk_status); if (hdr->rw_ops->rw_done(task, hdr, inode) != 0) return; if (task->tk_status < 0) nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset); else hdr->rw_ops->rw_result(task, hdr); } /* * Create an RPC task for the given read or write request and kick it. * The page must have been locked by the caller. * * It may happen that the page we're passed is not marked dirty. * This is the case if nfs_updatepage detects a conflicting request * that has been written but not committed. */ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr) { struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); struct nfs_page *req; struct page **pages, *last_page; struct list_head *head = &mirror->pg_list; struct nfs_commit_info cinfo; struct nfs_page_array *pg_array = &hdr->page_array; unsigned int pagecount, pageused; gfp_t gfp_flags = GFP_KERNEL; pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count); pg_array->npages = pagecount; if (pagecount <= ARRAY_SIZE(pg_array->page_array)) pg_array->pagevec = pg_array->page_array; else { pg_array->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags); if (!pg_array->pagevec) { pg_array->npages = 0; nfs_pgio_error(hdr); desc->pg_error = -ENOMEM; return desc->pg_error; } } nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq); pages = hdr->page_array.pagevec; last_page = NULL; pageused = 0; while (!list_empty(head)) { req = nfs_list_entry(head->next); nfs_list_move_request(req, &hdr->pages); if (!last_page || last_page != req->wb_page) { pageused++; if (pageused > pagecount) break; *pages++ = last_page = req->wb_page; } } if (WARN_ON_ONCE(pageused != pagecount)) { nfs_pgio_error(hdr); desc->pg_error = -EINVAL; return desc->pg_error; } if ((desc->pg_ioflags & FLUSH_COND_STABLE) && (desc->pg_moreio || nfs_reqs_to_commit(&cinfo))) desc->pg_ioflags &= ~FLUSH_COND_STABLE; /* Set up the argument struct */ nfs_pgio_rpcsetup(hdr, mirror->pg_count, desc->pg_ioflags, &cinfo); desc->pg_rpc_callops = &nfs_pgio_common_ops; return 0; } EXPORT_SYMBOL_GPL(nfs_generic_pgio); static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc) { struct nfs_pgio_header *hdr; int ret; hdr = nfs_pgio_header_alloc(desc->pg_rw_ops); if (!hdr) { desc->pg_error = -ENOMEM; return desc->pg_error; } nfs_pgheader_init(desc, hdr, nfs_pgio_header_free); ret = nfs_generic_pgio(desc, hdr); if (ret == 0) ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode), hdr, hdr->cred, NFS_PROTO(hdr->inode), desc->pg_rpc_callops, desc->pg_ioflags, RPC_TASK_CRED_NOREF); return ret; } static struct nfs_pgio_mirror * nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc, unsigned int mirror_count) { struct nfs_pgio_mirror *ret; unsigned int i; kfree(desc->pg_mirrors_dynamic); desc->pg_mirrors_dynamic = NULL; if (mirror_count == 1) return desc->pg_mirrors_static; ret = kmalloc_array(mirror_count, sizeof(*ret), GFP_KERNEL); if (ret != NULL) { for (i = 0; i < mirror_count; i++) nfs_pageio_mirror_init(&ret[i], desc->pg_bsize); desc->pg_mirrors_dynamic = ret; } return ret; } /* * nfs_pageio_setup_mirroring - determine if mirroring is to be used * by calling the pg_get_mirror_count op */ static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) { unsigned int mirror_count = 1; if (pgio->pg_ops->pg_get_mirror_count) mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req); if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0) return; if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) { pgio->pg_error = -EINVAL; return; } pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count); if (pgio->pg_mirrors == NULL) { pgio->pg_error = -ENOMEM; pgio->pg_mirrors = pgio->pg_mirrors_static; mirror_count = 1; } pgio->pg_mirror_count = mirror_count; } static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio) { pgio->pg_mirror_count = 1; pgio->pg_mirror_idx = 0; pgio->pg_mirrors = pgio->pg_mirrors_static; kfree(pgio->pg_mirrors_dynamic); pgio->pg_mirrors_dynamic = NULL; } static bool nfs_match_lock_context(const struct nfs_lock_context *l1, const struct nfs_lock_context *l2) { return l1->lockowner == l2->lockowner; } /** * nfs_coalesce_size - test two requests for compatibility * @prev: pointer to nfs_page * @req: pointer to nfs_page * @pgio: pointer to nfs_pagio_descriptor * * The nfs_page structures 'prev' and 'req' are compared to ensure that the * page data area they describe is contiguous, and that their RPC * credentials, NFSv4 open state, and lockowners are the same. * * Returns size of the request that can be coalesced */ static unsigned int nfs_coalesce_size(struct nfs_page *prev, struct nfs_page *req, struct nfs_pageio_descriptor *pgio) { struct file_lock_context *flctx; if (prev) { if (!nfs_match_open_context(nfs_req_openctx(req), nfs_req_openctx(prev))) return 0; flctx = d_inode(nfs_req_openctx(req)->dentry)->i_flctx; if (flctx != NULL && !(list_empty_careful(&flctx->flc_posix) && list_empty_careful(&flctx->flc_flock)) && !nfs_match_lock_context(req->wb_lock_context, prev->wb_lock_context)) return 0; if (req_offset(req) != req_offset(prev) + prev->wb_bytes) return 0; if (req->wb_page == prev->wb_page) { if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes) return 0; } else { if (req->wb_pgbase != 0 || prev->wb_pgbase + prev->wb_bytes != PAGE_SIZE) return 0; } } return pgio->pg_ops->pg_test(pgio, prev, req); } /** * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list. * @desc: destination io descriptor * @req: request * * If the request 'req' was successfully coalesced into the existing list * of pages 'desc', it returns the size of req. */ static unsigned int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc, struct nfs_page *req) { struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); struct nfs_page *prev = NULL; unsigned int size; if (mirror->pg_count != 0) { prev = nfs_list_entry(mirror->pg_list.prev); } else { if (desc->pg_ops->pg_init) desc->pg_ops->pg_init(desc, req); if (desc->pg_error < 0) return 0; mirror->pg_base = req->wb_pgbase; } if (desc->pg_maxretrans && req->wb_nio > desc->pg_maxretrans) { if (NFS_SERVER(desc->pg_inode)->flags & NFS_MOUNT_SOFTERR) desc->pg_error = -ETIMEDOUT; else desc->pg_error = -EIO; return 0; } size = nfs_coalesce_size(prev, req, desc); if (size < req->wb_bytes) return size; nfs_list_move_request(req, &mirror->pg_list); mirror->pg_count += req->wb_bytes; return req->wb_bytes; } /* * Helper for nfs_pageio_add_request and nfs_pageio_complete */ static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc) { struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); if (!list_empty(&mirror->pg_list)) { int error = desc->pg_ops->pg_doio(desc); if (error < 0) desc->pg_error = error; else mirror->pg_bytes_written += mirror->pg_count; } if (list_empty(&mirror->pg_list)) { mirror->pg_count = 0; mirror->pg_base = 0; } } static void nfs_pageio_cleanup_request(struct nfs_pageio_descriptor *desc, struct nfs_page *req) { LIST_HEAD(head); nfs_list_move_request(req, &head); desc->pg_completion_ops->error_cleanup(&head, desc->pg_error); } /** * nfs_pageio_add_request - Attempt to coalesce a request into a page list. * @desc: destination io descriptor * @req: request * * This may split a request into subrequests which are all part of the * same page group. If so, it will submit @req as the last one, to ensure * the pointer to @req is still valid in case of failure. * * Returns true if the request 'req' was successfully coalesced into the * existing list of pages 'desc'. */ static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, struct nfs_page *req) { struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); struct nfs_page *subreq; unsigned int size, subreq_size; nfs_page_group_lock(req); subreq = req; subreq_size = subreq->wb_bytes; for(;;) { size = nfs_pageio_do_add_request(desc, subreq); if (size == subreq_size) { /* We successfully submitted a request */ if (subreq == req) break; req->wb_pgbase += size; req->wb_bytes -= size; req->wb_offset += size; subreq_size = req->wb_bytes; subreq = req; continue; } if (WARN_ON_ONCE(subreq != req)) { nfs_page_group_unlock(req); nfs_pageio_cleanup_request(desc, subreq); subreq = req; subreq_size = req->wb_bytes; nfs_page_group_lock(req); } if (!size) { /* Can't coalesce any more, so do I/O */ nfs_page_group_unlock(req); desc->pg_moreio = 1; nfs_pageio_doio(desc); if (desc->pg_error < 0 || mirror->pg_recoalesce) return 0; /* retry add_request for this subreq */ nfs_page_group_lock(req); continue; } subreq = nfs_create_subreq(req, req->wb_pgbase, req->wb_offset, size); if (IS_ERR(subreq)) goto err_ptr; subreq_size = size; } nfs_page_group_unlock(req); return 1; err_ptr: desc->pg_error = PTR_ERR(subreq); nfs_page_group_unlock(req); return 0; } static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc) { struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc); LIST_HEAD(head); do { list_splice_init(&mirror->pg_list, &head); mirror->pg_bytes_written -= mirror->pg_count; mirror->pg_count = 0; mirror->pg_base = 0; mirror->pg_recoalesce = 0; while (!list_empty(&head)) { struct nfs_page *req; req = list_first_entry(&head, struct nfs_page, wb_list); if (__nfs_pageio_add_request(desc, req)) continue; if (desc->pg_error < 0) { list_splice_tail(&head, &mirror->pg_list); mirror->pg_recoalesce = 1; return 0; } break; } } while (mirror->pg_recoalesce); return 1; } static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc, struct nfs_page *req) { int ret; do { ret = __nfs_pageio_add_request(desc, req); if (ret) break; if (desc->pg_error < 0) break; ret = nfs_do_recoalesce(desc); } while (ret); return ret; } static void nfs_pageio_error_cleanup(struct nfs_pageio_descriptor *desc) { u32 midx; struct nfs_pgio_mirror *mirror; if (!desc->pg_error) return; for (midx = 0; midx < desc->pg_mirror_count; midx++) { mirror = &desc->pg_mirrors[midx]; desc->pg_completion_ops->error_cleanup(&mirror->pg_list, desc->pg_error); } } int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, struct nfs_page *req) { u32 midx; unsigned int pgbase, offset, bytes; struct nfs_page *dupreq; pgbase = req->wb_pgbase; offset = req->wb_offset; bytes = req->wb_bytes; nfs_pageio_setup_mirroring(desc, req); if (desc->pg_error < 0) goto out_failed; /* Create the mirror instances first, and fire them off */ for (midx = 1; midx < desc->pg_mirror_count; midx++) { nfs_page_group_lock(req); dupreq = nfs_create_subreq(req, pgbase, offset, bytes); nfs_page_group_unlock(req); if (IS_ERR(dupreq)) { desc->pg_error = PTR_ERR(dupreq); goto out_failed; } desc->pg_mirror_idx = midx; if (!nfs_pageio_add_request_mirror(desc, dupreq)) goto out_cleanup_subreq; } desc->pg_mirror_idx = 0; if (!nfs_pageio_add_request_mirror(desc, req)) goto out_failed; return 1; out_cleanup_subreq: nfs_pageio_cleanup_request(desc, dupreq); out_failed: nfs_pageio_error_cleanup(desc); return 0; } /* * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an * nfs_pageio_descriptor * @desc: pointer to io descriptor * @mirror_idx: pointer to mirror index */ static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc, u32 mirror_idx) { struct nfs_pgio_mirror *mirror = &desc->pg_mirrors[mirror_idx]; u32 restore_idx = desc->pg_mirror_idx; desc->pg_mirror_idx = mirror_idx; for (;;) { nfs_pageio_doio(desc); if (desc->pg_error < 0 || !mirror->pg_recoalesce) break; if (!nfs_do_recoalesce(desc)) break; } desc->pg_mirror_idx = restore_idx; } /* * nfs_pageio_resend - Transfer requests to new descriptor and resend * @hdr - the pgio header to move request from * @desc - the pageio descriptor to add requests to * * Try to move each request (nfs_page) from @hdr to @desc then attempt * to send them. * * Returns 0 on success and < 0 on error. */ int nfs_pageio_resend(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr) { LIST_HEAD(pages); desc->pg_io_completion = hdr->io_completion; desc->pg_dreq = hdr->dreq; list_splice_init(&hdr->pages, &pages); while (!list_empty(&pages)) { struct nfs_page *req = nfs_list_entry(pages.next); if (!nfs_pageio_add_request(desc, req)) break; } nfs_pageio_complete(desc); if (!list_empty(&pages)) { int err = desc->pg_error < 0 ? desc->pg_error : -EIO; hdr->completion_ops->error_cleanup(&pages, err); nfs_set_pgio_error(hdr, err, hdr->io_start); return err; } return 0; } EXPORT_SYMBOL_GPL(nfs_pageio_resend); /** * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor * @desc: pointer to io descriptor */ void nfs_pageio_complete(struct nfs_pageio_descriptor *desc) { u32 midx; for (midx = 0; midx < desc->pg_mirror_count; midx++) nfs_pageio_complete_mirror(desc, midx); if (desc->pg_error < 0) nfs_pageio_error_cleanup(desc); if (desc->pg_ops->pg_cleanup) desc->pg_ops->pg_cleanup(desc); nfs_pageio_cleanup_mirroring(desc); } /** * nfs_pageio_cond_complete - Conditional I/O completion * @desc: pointer to io descriptor * @index: page index * * It is important to ensure that processes don't try to take locks * on non-contiguous ranges of pages as that might deadlock. This * function should be called before attempting to wait on a locked * nfs_page. It will complete the I/O if the page index 'index' * is not contiguous with the existing list of pages in 'desc'. */ void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index) { struct nfs_pgio_mirror *mirror; struct nfs_page *prev; u32 midx; for (midx = 0; midx < desc->pg_mirror_count; midx++) { mirror = &desc->pg_mirrors[midx]; if (!list_empty(&mirror->pg_list)) { prev = nfs_list_entry(mirror->pg_list.prev); if (index != prev->wb_index + 1) { nfs_pageio_complete(desc); break; } } } } /* * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1) */ void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio) { nfs_pageio_complete(pgio); } int __init nfs_init_nfspagecache(void) { nfs_page_cachep = kmem_cache_create("nfs_page", sizeof(struct nfs_page), 0, SLAB_HWCACHE_ALIGN, NULL); if (nfs_page_cachep == NULL) return -ENOMEM; return 0; } void nfs_destroy_nfspagecache(void) { kmem_cache_destroy(nfs_page_cachep); } static const struct rpc_call_ops nfs_pgio_common_ops = { .rpc_call_prepare = nfs_pgio_prepare, .rpc_call_done = nfs_pgio_result, .rpc_release = nfs_pgio_release, }; const struct nfs_pageio_ops nfs_pgio_rw_ops = { .pg_test = nfs_generic_pg_test, .pg_doio = nfs_generic_pg_pgios, };