| /* |
| * 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_page.h> |
| #include <linux/nfs_fs.h> |
| #include <linux/nfs_mount.h> |
| #include <linux/export.h> |
| |
| #include "internal.h" |
| #include "pnfs.h" |
| |
| #define NFSDBG_FACILITY NFSDBG_PAGECACHE |
| |
| static struct kmem_cache *nfs_page_cachep; |
| static const struct rpc_call_ops nfs_pgio_common_ops; |
| |
| static bool nfs_pgarray_set(struct nfs_page_array *p, unsigned int pagecount) |
| { |
| p->npages = pagecount; |
| if (pagecount <= ARRAY_SIZE(p->page_array)) |
| p->pagevec = p->page_array; |
| else { |
| p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL); |
| if (!p->pagevec) |
| p->npages = 0; |
| } |
| return p->pagevec != NULL; |
| } |
| |
| void nfs_pgheader_init(struct nfs_pageio_descriptor *desc, |
| struct nfs_pgio_header *hdr, |
| void (*release)(struct nfs_pgio_header *hdr)) |
| { |
| hdr->req = nfs_list_entry(desc->pg_list.next); |
| hdr->inode = desc->pg_inode; |
| hdr->cred = hdr->req->wb_context->cred; |
| hdr->io_start = req_offset(hdr->req); |
| hdr->good_bytes = desc->pg_count; |
| hdr->dreq = desc->pg_dreq; |
| hdr->layout_private = desc->pg_layout_private; |
| hdr->release = release; |
| hdr->completion_ops = desc->pg_completion_ops; |
| if (hdr->completion_ops->init_hdr) |
| hdr->completion_ops->init_hdr(hdr); |
| } |
| EXPORT_SYMBOL_GPL(nfs_pgheader_init); |
| |
| void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos) |
| { |
| spin_lock(&hdr->lock); |
| if (pos < hdr->io_start + hdr->good_bytes) { |
| set_bit(NFS_IOHDR_ERROR, &hdr->flags); |
| clear_bit(NFS_IOHDR_EOF, &hdr->flags); |
| hdr->good_bytes = pos - hdr->io_start; |
| hdr->error = error; |
| } |
| spin_unlock(&hdr->lock); |
| } |
| |
| static inline struct nfs_page * |
| nfs_page_alloc(void) |
| { |
| struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_NOIO); |
| 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); |
| } |
| |
| static void |
| nfs_iocounter_inc(struct nfs_io_counter *c) |
| { |
| atomic_inc(&c->io_count); |
| } |
| |
| static void |
| nfs_iocounter_dec(struct nfs_io_counter *c) |
| { |
| if (atomic_dec_and_test(&c->io_count)) { |
| clear_bit(NFS_IO_INPROGRESS, &c->flags); |
| smp_mb__after_atomic(); |
| wake_up_bit(&c->flags, NFS_IO_INPROGRESS); |
| } |
| } |
| |
| static int |
| __nfs_iocounter_wait(struct nfs_io_counter *c) |
| { |
| wait_queue_head_t *wq = bit_waitqueue(&c->flags, NFS_IO_INPROGRESS); |
| DEFINE_WAIT_BIT(q, &c->flags, NFS_IO_INPROGRESS); |
| int ret = 0; |
| |
| do { |
| prepare_to_wait(wq, &q.wait, TASK_KILLABLE); |
| set_bit(NFS_IO_INPROGRESS, &c->flags); |
| if (atomic_read(&c->io_count) == 0) |
| break; |
| ret = nfs_wait_bit_killable(&q.key); |
| } while (atomic_read(&c->io_count) != 0 && !ret); |
| finish_wait(wq, &q.wait); |
| return ret; |
| } |
| |
| /** |
| * nfs_iocounter_wait - wait for i/o to complete |
| * @c: nfs_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_io_counter *c) |
| { |
| if (atomic_read(&c->io_count) == 0) |
| return 0; |
| return __nfs_iocounter_wait(c); |
| } |
| |
| /* |
| * nfs_page_group_lock - lock the head of the page group |
| * @req - request in group that is to be locked |
| * @nonblock - if true don't block waiting for lock |
| * |
| * this lock must be held if modifying the page group list |
| * |
| * return 0 on success, < 0 on error: -EDELAY if nonblocking or the |
| * result from wait_on_bit_lock |
| * |
| * NOTE: calling with nonblock=false should always have set the |
| * lock bit (see fs/buffer.c and other uses of wait_on_bit_lock |
| * with TASK_UNINTERRUPTIBLE), so there is no need to check the result. |
| */ |
| int |
| nfs_page_group_lock(struct nfs_page *req, bool nonblock) |
| { |
| struct nfs_page *head = req->wb_head; |
| |
| WARN_ON_ONCE(head != head->wb_head); |
| |
| if (!test_and_set_bit(PG_HEADLOCK, &head->wb_flags)) |
| return 0; |
| |
| if (!nonblock) |
| return wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK, |
| TASK_UNINTERRUPTIBLE); |
| |
| return -EAGAIN; |
| } |
| |
| /* |
| * nfs_page_group_lock_wait - wait for the lock to clear, but don't grab it |
| * @req - a request in the group |
| * |
| * This is a blocking call to wait for the group lock to be cleared. |
| */ |
| void |
| nfs_page_group_lock_wait(struct nfs_page *req) |
| { |
| struct nfs_page *head = req->wb_head; |
| |
| WARN_ON_ONCE(head != head->wb_head); |
| |
| wait_on_bit(&head->wb_flags, PG_HEADLOCK, |
| TASK_UNINTERRUPTIBLE); |
| } |
| |
| /* |
| * 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) |
| { |
| struct nfs_page *head = req->wb_head; |
| |
| WARN_ON_ONCE(head != head->wb_head); |
| |
| smp_mb__before_atomic(); |
| clear_bit(PG_HEADLOCK, &head->wb_flags); |
| smp_mb__after_atomic(); |
| wake_up_bit(&head->wb_flags, PG_HEADLOCK); |
| } |
| |
| /* |
| * 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, false); |
| 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) |
| { |
| 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 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)) { |
| set_bit(PG_INODE_REF, &req->wb_flags); |
| kref_get(&req->wb_kref); |
| } |
| } |
| } |
| |
| /* |
| * 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 *tmp, *next; |
| |
| /* subrequests must release the ref on the head request */ |
| if (req->wb_head != req) |
| nfs_release_request(req->wb_head); |
| |
| if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN)) |
| return; |
| |
| 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); |
| } |
| |
| /** |
| * nfs_create_request - Create an NFS read/write request. |
| * @ctx: open context to use |
| * @page: page to write |
| * @last: last nfs request created for this page group or NULL if head |
| * @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, |
| struct nfs_page *last, unsigned int offset, |
| unsigned int count) |
| { |
| struct nfs_page *req; |
| struct nfs_lock_context *l_ctx; |
| |
| 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); |
| |
| /* get lock context early so we can deal with alloc failures */ |
| l_ctx = nfs_get_lock_context(ctx); |
| if (IS_ERR(l_ctx)) { |
| nfs_page_free(req); |
| return ERR_CAST(l_ctx); |
| } |
| req->wb_lock_context = l_ctx; |
| nfs_iocounter_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; |
| req->wb_index = page_file_index(page); |
| page_cache_get(page); |
| req->wb_offset = offset; |
| req->wb_pgbase = offset; |
| req->wb_bytes = count; |
| req->wb_context = get_nfs_open_context(ctx); |
| kref_init(&req->wb_kref); |
| nfs_page_group_init(req, last); |
| return req; |
| } |
| |
| /** |
| * nfs_unlock_request - Unlock request and wake up sleepers. |
| * @req: |
| */ |
| 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(); |
| wake_up_bit(&req->wb_flags, PG_BUSY); |
| } |
| |
| /** |
| * nfs_unlock_and_release_request - Unlock request and release the nfs_page |
| * @req: |
| */ |
| 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_open_context *ctx = req->wb_context; |
| struct nfs_lock_context *l_ctx = req->wb_lock_context; |
| |
| if (page != NULL) { |
| page_cache_release(page); |
| req->wb_page = NULL; |
| } |
| if (l_ctx != NULL) { |
| nfs_iocounter_dec(&l_ctx->io_count); |
| nfs_put_lock_context(l_ctx); |
| req->wb_lock_context = NULL; |
| } |
| if (ctx != NULL) { |
| put_nfs_open_context(ctx); |
| req->wb_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); |
| } |
| |
| /** |
| * 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) |
| { |
| return wait_on_bit_io(&req->wb_flags, PG_BUSY, |
| TASK_UNINTERRUPTIBLE); |
| } |
| |
| /* |
| * 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 can 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) |
| { |
| if (desc->pg_count > desc->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 (((desc->pg_count + req->wb_bytes) >> PAGE_SHIFT) * |
| sizeof(struct page) > PAGE_SIZE) |
| return 0; |
| |
| return min(desc->pg_bsize - desc->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); |
| spin_lock_init(&hdr->lock); |
| hdr->rw_ops = ops; |
| } |
| return hdr; |
| } |
| EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc); |
| |
| /* |
| * 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) |
| { |
| hdr->rw_ops->rw_free_header(hdr); |
| } |
| EXPORT_SYMBOL_GPL(nfs_pgio_header_free); |
| |
| /** |
| * 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 |
| */ |
| 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); |
| } |
| EXPORT_SYMBOL_GPL(nfs_pgio_data_destroy); |
| |
| /** |
| * nfs_pgio_rpcsetup - Set up arguments for a pageio call |
| * @hdr: The pageio hdr |
| * @count: Number of bytes to read |
| * @offset: Initial offset |
| * @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, unsigned int offset, |
| 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) + offset; |
| /* pnfs_set_layoutcommit needs this */ |
| hdr->mds_offset = hdr->args.offset; |
| hdr->args.pgbase = req->wb_pgbase + offset; |
| hdr->args.pages = hdr->page_array.pagevec; |
| hdr->args.count = count; |
| hdr->args.context = get_nfs_open_context(req->wb_context); |
| 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; |
| default: |
| hdr->args.stable = NFS_FILE_SYNC; |
| } |
| |
| hdr->res.fattr = &hdr->fattr; |
| hdr->res.count = count; |
| 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 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 = hdr->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, |
| }; |
| int ret = 0; |
| |
| hdr->rw_ops->rw_initiate(hdr, &msg, &task_setup_data, how); |
| |
| dprintk("NFS: %5u initiated pgio call " |
| "(req %s/%llu, %u bytes @ offset %llu)\n", |
| hdr->task.tk_pid, |
| 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)) { |
| ret = PTR_ERR(task); |
| goto out; |
| } |
| if (how & FLUSH_SYNC) { |
| ret = rpc_wait_for_completion_task(task); |
| if (ret == 0) |
| ret = task->tk_status; |
| } |
| rpc_put_task(task); |
| out: |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(nfs_initiate_pgio); |
| |
| /** |
| * nfs_pgio_error - Clean up from a pageio error |
| * @desc: IO descriptor |
| * @hdr: pageio header |
| */ |
| static int nfs_pgio_error(struct nfs_pageio_descriptor *desc, |
| struct nfs_pgio_header *hdr) |
| { |
| set_bit(NFS_IOHDR_REDO, &hdr->flags); |
| nfs_pgio_data_destroy(hdr); |
| hdr->completion_ops->completion(hdr); |
| desc->pg_completion_ops->error_cleanup(&desc->pg_list); |
| return -ENOMEM; |
| } |
| |
| /** |
| * 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; |
| if (hdr->rw_ops->rw_release) |
| hdr->rw_ops->rw_release(hdr); |
| nfs_pgio_data_destroy(hdr); |
| hdr->completion_ops->completion(hdr); |
| } |
| |
| /** |
| * nfs_pageio_init - initialise a page io descriptor |
| * @desc: pointer to descriptor |
| * @inode: pointer to inode |
| * @doio: pointer to io function |
| * @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) |
| { |
| INIT_LIST_HEAD(&desc->pg_list); |
| desc->pg_bytes_written = 0; |
| desc->pg_count = 0; |
| desc->pg_bsize = bsize; |
| desc->pg_base = 0; |
| desc->pg_moreio = 0; |
| desc->pg_recoalesce = 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_dreq = NULL; |
| desc->pg_layout_private = NULL; |
| } |
| EXPORT_SYMBOL_GPL(nfs_pageio_init); |
| |
| /** |
| * 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_page *req; |
| struct page **pages, |
| *last_page; |
| struct list_head *head = &desc->pg_list; |
| struct nfs_commit_info cinfo; |
| unsigned int pagecount, pageused; |
| |
| pagecount = nfs_page_array_len(desc->pg_base, desc->pg_count); |
| if (!nfs_pgarray_set(&hdr->page_array, pagecount)) |
| return nfs_pgio_error(desc, hdr); |
| |
| 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_remove_request(req); |
| nfs_list_add_request(req, &hdr->pages); |
| |
| if (WARN_ON_ONCE(pageused >= pagecount)) |
| return nfs_pgio_error(desc, hdr); |
| |
| if (!last_page || last_page != req->wb_page) { |
| *pages++ = last_page = req->wb_page; |
| pageused++; |
| } |
| } |
| if (WARN_ON_ONCE(pageused != pagecount)) |
| return nfs_pgio_error(desc, hdr); |
| |
| 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, desc->pg_count, 0, 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_completion_ops->error_cleanup(&desc->pg_list); |
| return -ENOMEM; |
| } |
| 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, desc->pg_rpc_callops, |
| desc->pg_ioflags, 0); |
| return ret; |
| } |
| |
| static bool nfs_match_open_context(const struct nfs_open_context *ctx1, |
| const struct nfs_open_context *ctx2) |
| { |
| return ctx1->cred == ctx2->cred && ctx1->state == ctx2->state; |
| } |
| |
| static bool nfs_match_lock_context(const struct nfs_lock_context *l1, |
| const struct nfs_lock_context *l2) |
| { |
| return l1->lockowner.l_owner == l2->lockowner.l_owner |
| && l1->lockowner.l_pid == l2->lockowner.l_pid; |
| } |
| |
| /** |
| * nfs_can_coalesce_requests - test two requests for compatibility |
| * @prev: pointer to nfs_page |
| * @req: pointer to nfs_page |
| * |
| * 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. |
| * |
| * Return 'true' if this is the case, else return 'false'. |
| */ |
| static bool nfs_can_coalesce_requests(struct nfs_page *prev, |
| struct nfs_page *req, |
| struct nfs_pageio_descriptor *pgio) |
| { |
| size_t size; |
| |
| if (prev) { |
| if (!nfs_match_open_context(req->wb_context, prev->wb_context)) |
| return false; |
| if (req->wb_context->dentry->d_inode->i_flock != NULL && |
| !nfs_match_lock_context(req->wb_lock_context, |
| prev->wb_lock_context)) |
| return false; |
| if (req_offset(req) != req_offset(prev) + prev->wb_bytes) |
| return false; |
| if (req->wb_page == prev->wb_page) { |
| if (req->wb_pgbase != prev->wb_pgbase + prev->wb_bytes) |
| return false; |
| } else { |
| if (req->wb_pgbase != 0 || |
| prev->wb_pgbase + prev->wb_bytes != PAGE_CACHE_SIZE) |
| return false; |
| } |
| } |
| size = pgio->pg_ops->pg_test(pgio, prev, req); |
| WARN_ON_ONCE(size > req->wb_bytes); |
| if (size && size < req->wb_bytes) |
| req->wb_bytes = size; |
| return size > 0; |
| } |
| |
| /** |
| * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list. |
| * @desc: destination io descriptor |
| * @req: request |
| * |
| * Returns true if the request 'req' was successfully coalesced into the |
| * existing list of pages 'desc'. |
| */ |
| static int nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc, |
| struct nfs_page *req) |
| { |
| struct nfs_page *prev = NULL; |
| if (desc->pg_count != 0) { |
| prev = nfs_list_entry(desc->pg_list.prev); |
| } else { |
| if (desc->pg_ops->pg_init) |
| desc->pg_ops->pg_init(desc, req); |
| desc->pg_base = req->wb_pgbase; |
| } |
| if (!nfs_can_coalesce_requests(prev, req, desc)) |
| return 0; |
| nfs_list_remove_request(req); |
| nfs_list_add_request(req, &desc->pg_list); |
| desc->pg_count += req->wb_bytes; |
| return 1; |
| } |
| |
| /* |
| * Helper for nfs_pageio_add_request and nfs_pageio_complete |
| */ |
| static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc) |
| { |
| if (!list_empty(&desc->pg_list)) { |
| int error = desc->pg_ops->pg_doio(desc); |
| if (error < 0) |
| desc->pg_error = error; |
| else |
| desc->pg_bytes_written += desc->pg_count; |
| } |
| if (list_empty(&desc->pg_list)) { |
| desc->pg_count = 0; |
| desc->pg_base = 0; |
| } |
| } |
| |
| /** |
| * 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. |
| * |
| * 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_page *subreq; |
| unsigned int bytes_left = 0; |
| unsigned int offset, pgbase; |
| |
| nfs_page_group_lock(req, false); |
| |
| subreq = req; |
| bytes_left = subreq->wb_bytes; |
| offset = subreq->wb_offset; |
| pgbase = subreq->wb_pgbase; |
| |
| do { |
| if (!nfs_pageio_do_add_request(desc, subreq)) { |
| /* make sure pg_test call(s) did nothing */ |
| WARN_ON_ONCE(subreq->wb_bytes != bytes_left); |
| WARN_ON_ONCE(subreq->wb_offset != offset); |
| WARN_ON_ONCE(subreq->wb_pgbase != pgbase); |
| |
| nfs_page_group_unlock(req); |
| desc->pg_moreio = 1; |
| nfs_pageio_doio(desc); |
| if (desc->pg_error < 0) |
| return 0; |
| if (desc->pg_recoalesce) |
| return 0; |
| /* retry add_request for this subreq */ |
| nfs_page_group_lock(req, false); |
| continue; |
| } |
| |
| /* check for buggy pg_test call(s) */ |
| WARN_ON_ONCE(subreq->wb_bytes + subreq->wb_pgbase > PAGE_SIZE); |
| WARN_ON_ONCE(subreq->wb_bytes > bytes_left); |
| WARN_ON_ONCE(subreq->wb_bytes == 0); |
| |
| bytes_left -= subreq->wb_bytes; |
| offset += subreq->wb_bytes; |
| pgbase += subreq->wb_bytes; |
| |
| if (bytes_left) { |
| subreq = nfs_create_request(req->wb_context, |
| req->wb_page, |
| subreq, pgbase, bytes_left); |
| if (IS_ERR(subreq)) |
| goto err_ptr; |
| nfs_lock_request(subreq); |
| subreq->wb_offset = offset; |
| subreq->wb_index = req->wb_index; |
| } |
| } while (bytes_left > 0); |
| |
| 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) |
| { |
| LIST_HEAD(head); |
| |
| do { |
| list_splice_init(&desc->pg_list, &head); |
| desc->pg_bytes_written -= desc->pg_count; |
| desc->pg_count = 0; |
| desc->pg_base = 0; |
| desc->pg_recoalesce = 0; |
| desc->pg_moreio = 0; |
| |
| while (!list_empty(&head)) { |
| struct nfs_page *req; |
| |
| req = list_first_entry(&head, struct nfs_page, wb_list); |
| nfs_list_remove_request(req); |
| if (__nfs_pageio_add_request(desc, req)) |
| continue; |
| if (desc->pg_error < 0) |
| return 0; |
| break; |
| } |
| } while (desc->pg_recoalesce); |
| return 1; |
| } |
| |
| int nfs_pageio_add_request(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; |
| } |
| |
| /* |
| * 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(failed); |
| |
| desc->pg_dreq = hdr->dreq; |
| while (!list_empty(&hdr->pages)) { |
| struct nfs_page *req = nfs_list_entry(hdr->pages.next); |
| |
| nfs_list_remove_request(req); |
| if (!nfs_pageio_add_request(desc, req)) |
| nfs_list_add_request(req, &failed); |
| } |
| nfs_pageio_complete(desc); |
| if (!list_empty(&failed)) { |
| list_move(&failed, &hdr->pages); |
| return -EIO; |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(nfs_pageio_resend); |
| |
| /** |
| * nfs_pageio_complete - Complete I/O on an nfs_pageio_descriptor |
| * @desc: pointer to io descriptor |
| */ |
| void nfs_pageio_complete(struct nfs_pageio_descriptor *desc) |
| { |
| for (;;) { |
| nfs_pageio_doio(desc); |
| if (!desc->pg_recoalesce) |
| break; |
| if (!nfs_do_recoalesce(desc)) |
| break; |
| } |
| } |
| |
| /** |
| * 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) |
| { |
| if (!list_empty(&desc->pg_list)) { |
| struct nfs_page *prev = nfs_list_entry(desc->pg_list.prev); |
| if (index != prev->wb_index + 1) |
| nfs_pageio_complete(desc); |
| } |
| } |
| |
| 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, |
| }; |