| /* |
| * linux/fs/nfs/direct.c |
| * |
| * Copyright (C) 2003 by Chuck Lever <cel@netapp.com> |
| * |
| * High-performance uncached I/O for the Linux NFS client |
| * |
| * There are important applications whose performance or correctness |
| * depends on uncached access to file data. Database clusters |
| * (multiple copies of the same instance running on separate hosts) |
| * implement their own cache coherency protocol that subsumes file |
| * system cache protocols. Applications that process datasets |
| * considerably larger than the client's memory do not always benefit |
| * from a local cache. A streaming video server, for instance, has no |
| * need to cache the contents of a file. |
| * |
| * When an application requests uncached I/O, all read and write requests |
| * are made directly to the server; data stored or fetched via these |
| * requests is not cached in the Linux page cache. The client does not |
| * correct unaligned requests from applications. All requested bytes are |
| * held on permanent storage before a direct write system call returns to |
| * an application. |
| * |
| * Solaris implements an uncached I/O facility called directio() that |
| * is used for backups and sequential I/O to very large files. Solaris |
| * also supports uncaching whole NFS partitions with "-o forcedirectio," |
| * an undocumented mount option. |
| * |
| * Designed by Jeff Kimmel, Chuck Lever, and Trond Myklebust, with |
| * help from Andrew Morton. |
| * |
| * 18 Dec 2001 Initial implementation for 2.4 --cel |
| * 08 Jul 2002 Version for 2.4.19, with bug fixes --trondmy |
| * 08 Jun 2003 Port to 2.5 APIs --cel |
| * 31 Mar 2004 Handle direct I/O without VFS support --cel |
| * 15 Sep 2004 Parallel async reads --cel |
| * 04 May 2005 support O_DIRECT with aio --cel |
| * |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/errno.h> |
| #include <linux/sched.h> |
| #include <linux/kernel.h> |
| #include <linux/smp_lock.h> |
| #include <linux/file.h> |
| #include <linux/pagemap.h> |
| #include <linux/kref.h> |
| |
| #include <linux/nfs_fs.h> |
| #include <linux/nfs_page.h> |
| #include <linux/sunrpc/clnt.h> |
| |
| #include <asm/system.h> |
| #include <asm/uaccess.h> |
| #include <asm/atomic.h> |
| |
| #include "iostat.h" |
| |
| #define NFSDBG_FACILITY NFSDBG_VFS |
| |
| static kmem_cache_t *nfs_direct_cachep; |
| |
| /* |
| * This represents a set of asynchronous requests that we're waiting on |
| */ |
| struct nfs_direct_req { |
| struct kref kref; /* release manager */ |
| |
| /* I/O parameters */ |
| struct list_head list, /* nfs_read/write_data structs */ |
| rewrite_list; /* saved nfs_write_data structs */ |
| struct nfs_open_context *ctx; /* file open context info */ |
| struct kiocb * iocb; /* controlling i/o request */ |
| struct inode * inode; /* target file of i/o */ |
| |
| /* completion state */ |
| atomic_t io_count; /* i/os we're waiting for */ |
| spinlock_t lock; /* protect completion state */ |
| ssize_t count, /* bytes actually processed */ |
| error; /* any reported error */ |
| struct completion completion; /* wait for i/o completion */ |
| |
| /* commit state */ |
| struct nfs_write_data * commit_data; /* special write_data for commits */ |
| int flags; |
| #define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */ |
| #define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */ |
| struct nfs_writeverf verf; /* unstable write verifier */ |
| }; |
| |
| static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode); |
| static const struct rpc_call_ops nfs_write_direct_ops; |
| |
| static inline void get_dreq(struct nfs_direct_req *dreq) |
| { |
| atomic_inc(&dreq->io_count); |
| } |
| |
| static inline int put_dreq(struct nfs_direct_req *dreq) |
| { |
| return atomic_dec_and_test(&dreq->io_count); |
| } |
| |
| /* |
| * "size" is never larger than rsize or wsize. |
| */ |
| static inline int nfs_direct_count_pages(unsigned long user_addr, size_t size) |
| { |
| int page_count; |
| |
| page_count = (user_addr + size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| page_count -= user_addr >> PAGE_SHIFT; |
| BUG_ON(page_count < 0); |
| |
| return page_count; |
| } |
| |
| /** |
| * nfs_direct_IO - NFS address space operation for direct I/O |
| * @rw: direction (read or write) |
| * @iocb: target I/O control block |
| * @iov: array of vectors that define I/O buffer |
| * @pos: offset in file to begin the operation |
| * @nr_segs: size of iovec array |
| * |
| * The presence of this routine in the address space ops vector means |
| * the NFS client supports direct I/O. However, we shunt off direct |
| * read and write requests before the VFS gets them, so this method |
| * should never be called. |
| */ |
| ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs) |
| { |
| dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n", |
| iocb->ki_filp->f_dentry->d_name.name, |
| (long long) pos, nr_segs); |
| |
| return -EINVAL; |
| } |
| |
| static void nfs_direct_dirty_pages(struct page **pages, int npages) |
| { |
| int i; |
| for (i = 0; i < npages; i++) { |
| struct page *page = pages[i]; |
| if (!PageCompound(page)) |
| set_page_dirty_lock(page); |
| } |
| } |
| |
| static void nfs_direct_release_pages(struct page **pages, int npages) |
| { |
| int i; |
| for (i = 0; i < npages; i++) |
| page_cache_release(pages[i]); |
| } |
| |
| static inline struct nfs_direct_req *nfs_direct_req_alloc(void) |
| { |
| struct nfs_direct_req *dreq; |
| |
| dreq = kmem_cache_alloc(nfs_direct_cachep, SLAB_KERNEL); |
| if (!dreq) |
| return NULL; |
| |
| kref_init(&dreq->kref); |
| init_completion(&dreq->completion); |
| INIT_LIST_HEAD(&dreq->list); |
| INIT_LIST_HEAD(&dreq->rewrite_list); |
| dreq->iocb = NULL; |
| dreq->ctx = NULL; |
| spin_lock_init(&dreq->lock); |
| atomic_set(&dreq->io_count, 0); |
| dreq->count = 0; |
| dreq->error = 0; |
| dreq->flags = 0; |
| |
| return dreq; |
| } |
| |
| static void nfs_direct_req_release(struct kref *kref) |
| { |
| struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref); |
| |
| if (dreq->ctx != NULL) |
| put_nfs_open_context(dreq->ctx); |
| kmem_cache_free(nfs_direct_cachep, dreq); |
| } |
| |
| /* |
| * Collects and returns the final error value/byte-count. |
| */ |
| static ssize_t nfs_direct_wait(struct nfs_direct_req *dreq) |
| { |
| ssize_t result = -EIOCBQUEUED; |
| |
| /* Async requests don't wait here */ |
| if (dreq->iocb) |
| goto out; |
| |
| result = wait_for_completion_interruptible(&dreq->completion); |
| |
| if (!result) |
| result = dreq->error; |
| if (!result) |
| result = dreq->count; |
| |
| out: |
| kref_put(&dreq->kref, nfs_direct_req_release); |
| return (ssize_t) result; |
| } |
| |
| /* |
| * Synchronous I/O uses a stack-allocated iocb. Thus we can't trust |
| * the iocb is still valid here if this is a synchronous request. |
| */ |
| static void nfs_direct_complete(struct nfs_direct_req *dreq) |
| { |
| if (dreq->iocb) { |
| long res = (long) dreq->error; |
| if (!res) |
| res = (long) dreq->count; |
| aio_complete(dreq->iocb, res, 0); |
| } |
| complete_all(&dreq->completion); |
| |
| kref_put(&dreq->kref, nfs_direct_req_release); |
| } |
| |
| /* |
| * Note we also set the number of requests we have in the dreq when we are |
| * done. This prevents races with I/O completion so we will always wait |
| * until all requests have been dispatched and completed. |
| */ |
| static struct nfs_direct_req *nfs_direct_read_alloc(size_t nbytes, size_t rsize) |
| { |
| struct list_head *list; |
| struct nfs_direct_req *dreq; |
| unsigned int rpages = (rsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| |
| dreq = nfs_direct_req_alloc(); |
| if (!dreq) |
| return NULL; |
| |
| list = &dreq->list; |
| for(;;) { |
| struct nfs_read_data *data = nfs_readdata_alloc(rpages); |
| |
| if (unlikely(!data)) { |
| while (!list_empty(list)) { |
| data = list_entry(list->next, |
| struct nfs_read_data, pages); |
| list_del(&data->pages); |
| nfs_readdata_free(data); |
| } |
| kref_put(&dreq->kref, nfs_direct_req_release); |
| return NULL; |
| } |
| |
| INIT_LIST_HEAD(&data->pages); |
| list_add(&data->pages, list); |
| |
| data->req = (struct nfs_page *) dreq; |
| get_dreq(dreq); |
| if (nbytes <= rsize) |
| break; |
| nbytes -= rsize; |
| } |
| kref_get(&dreq->kref); |
| return dreq; |
| } |
| |
| /* |
| * We must hold a reference to all the pages in this direct read request |
| * until the RPCs complete. This could be long *after* we are woken up in |
| * nfs_direct_wait (for instance, if someone hits ^C on a slow server). |
| */ |
| static void nfs_direct_read_result(struct rpc_task *task, void *calldata) |
| { |
| struct nfs_read_data *data = calldata; |
| struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req; |
| |
| if (nfs_readpage_result(task, data) != 0) |
| return; |
| |
| nfs_direct_dirty_pages(data->pagevec, data->npages); |
| nfs_direct_release_pages(data->pagevec, data->npages); |
| |
| spin_lock(&dreq->lock); |
| |
| if (likely(task->tk_status >= 0)) |
| dreq->count += data->res.count; |
| else |
| dreq->error = task->tk_status; |
| |
| spin_unlock(&dreq->lock); |
| |
| if (put_dreq(dreq)) |
| nfs_direct_complete(dreq); |
| } |
| |
| static const struct rpc_call_ops nfs_read_direct_ops = { |
| .rpc_call_done = nfs_direct_read_result, |
| .rpc_release = nfs_readdata_release, |
| }; |
| |
| /* |
| * For each nfs_read_data struct that was allocated on the list, dispatch |
| * an NFS READ operation. If get_user_pages() fails, we stop sending reads. |
| * Read length accounting is handled by nfs_direct_read_result(). |
| * Otherwise, if no requests have been sent, just return an error. |
| */ |
| static ssize_t nfs_direct_read_schedule(struct nfs_direct_req *dreq, unsigned long user_addr, size_t count, loff_t pos) |
| { |
| struct nfs_open_context *ctx = dreq->ctx; |
| struct inode *inode = ctx->dentry->d_inode; |
| struct list_head *list = &dreq->list; |
| size_t rsize = NFS_SERVER(inode)->rsize; |
| unsigned int pgbase; |
| int result; |
| ssize_t started = 0; |
| struct nfs_read_data *data; |
| |
| pgbase = user_addr & ~PAGE_MASK; |
| do { |
| size_t bytes; |
| |
| bytes = rsize; |
| if (count < rsize) |
| bytes = count; |
| |
| BUG_ON(list_empty(list)); |
| data = list_entry(list->next, struct nfs_read_data, pages); |
| list_del_init(&data->pages); |
| |
| data->npages = nfs_direct_count_pages(user_addr, bytes); |
| down_read(¤t->mm->mmap_sem); |
| result = get_user_pages(current, current->mm, user_addr, |
| data->npages, 1, 0, data->pagevec, NULL); |
| up_read(¤t->mm->mmap_sem); |
| if (unlikely(result < data->npages)) |
| goto out_err; |
| |
| data->inode = inode; |
| data->cred = ctx->cred; |
| data->args.fh = NFS_FH(inode); |
| data->args.context = ctx; |
| data->args.offset = pos; |
| data->args.pgbase = pgbase; |
| data->args.pages = data->pagevec; |
| data->args.count = bytes; |
| data->res.fattr = &data->fattr; |
| data->res.eof = 0; |
| data->res.count = bytes; |
| |
| rpc_init_task(&data->task, NFS_CLIENT(inode), RPC_TASK_ASYNC, |
| &nfs_read_direct_ops, data); |
| NFS_PROTO(inode)->read_setup(data); |
| |
| data->task.tk_cookie = (unsigned long) inode; |
| |
| lock_kernel(); |
| rpc_execute(&data->task); |
| unlock_kernel(); |
| |
| dfprintk(VFS, "NFS: %5u initiated direct read call (req %s/%Ld, %zu bytes @ offset %Lu)\n", |
| data->task.tk_pid, |
| inode->i_sb->s_id, |
| (long long)NFS_FILEID(inode), |
| bytes, |
| (unsigned long long)data->args.offset); |
| |
| started += bytes; |
| user_addr += bytes; |
| pos += bytes; |
| pgbase += bytes; |
| pgbase &= ~PAGE_MASK; |
| |
| count -= bytes; |
| } while (count != 0); |
| BUG_ON(!list_empty(list)); |
| return 0; |
| |
| out_err: |
| if (result > 0) |
| nfs_direct_release_pages(data->pagevec, result); |
| |
| list_add(&data->pages, list); |
| while (!list_empty(list)) { |
| data = list_entry(list->next, struct nfs_read_data, pages); |
| list_del(&data->pages); |
| nfs_readdata_free(data); |
| if (put_dreq(dreq)) |
| nfs_direct_complete(dreq); |
| } |
| |
| if (started) |
| return 0; |
| return result < 0 ? (ssize_t) result : -EFAULT; |
| } |
| |
| static ssize_t nfs_direct_read(struct kiocb *iocb, unsigned long user_addr, size_t count, loff_t pos) |
| { |
| ssize_t result; |
| sigset_t oldset; |
| struct inode *inode = iocb->ki_filp->f_mapping->host; |
| struct rpc_clnt *clnt = NFS_CLIENT(inode); |
| struct nfs_direct_req *dreq; |
| |
| dreq = nfs_direct_read_alloc(count, NFS_SERVER(inode)->rsize); |
| if (!dreq) |
| return -ENOMEM; |
| |
| dreq->inode = inode; |
| dreq->ctx = get_nfs_open_context((struct nfs_open_context *)iocb->ki_filp->private_data); |
| if (!is_sync_kiocb(iocb)) |
| dreq->iocb = iocb; |
| |
| nfs_add_stats(inode, NFSIOS_DIRECTREADBYTES, count); |
| rpc_clnt_sigmask(clnt, &oldset); |
| result = nfs_direct_read_schedule(dreq, user_addr, count, pos); |
| if (!result) |
| result = nfs_direct_wait(dreq); |
| rpc_clnt_sigunmask(clnt, &oldset); |
| |
| return result; |
| } |
| |
| static void nfs_direct_free_writedata(struct nfs_direct_req *dreq) |
| { |
| list_splice_init(&dreq->rewrite_list, &dreq->list); |
| while (!list_empty(&dreq->list)) { |
| struct nfs_write_data *data = list_entry(dreq->list.next, struct nfs_write_data, pages); |
| list_del(&data->pages); |
| nfs_direct_release_pages(data->pagevec, data->npages); |
| nfs_writedata_release(data); |
| } |
| } |
| |
| #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4) |
| static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq) |
| { |
| struct inode *inode = dreq->inode; |
| struct list_head *p; |
| struct nfs_write_data *data; |
| |
| dreq->count = 0; |
| get_dreq(dreq); |
| |
| list_for_each(p, &dreq->rewrite_list) { |
| data = list_entry(p, struct nfs_write_data, pages); |
| |
| get_dreq(dreq); |
| |
| /* |
| * Reset data->res. |
| */ |
| nfs_fattr_init(&data->fattr); |
| data->res.count = data->args.count; |
| memset(&data->verf, 0, sizeof(data->verf)); |
| |
| /* |
| * Reuse data->task; data->args should not have changed |
| * since the original request was sent. |
| */ |
| rpc_init_task(&data->task, NFS_CLIENT(inode), RPC_TASK_ASYNC, |
| &nfs_write_direct_ops, data); |
| NFS_PROTO(inode)->write_setup(data, FLUSH_STABLE); |
| |
| data->task.tk_priority = RPC_PRIORITY_NORMAL; |
| data->task.tk_cookie = (unsigned long) inode; |
| |
| /* |
| * We're called via an RPC callback, so BKL is already held. |
| */ |
| rpc_execute(&data->task); |
| |
| dprintk("NFS: %5u rescheduled direct write call (req %s/%Ld, %u bytes @ offset %Lu)\n", |
| data->task.tk_pid, |
| inode->i_sb->s_id, |
| (long long)NFS_FILEID(inode), |
| data->args.count, |
| (unsigned long long)data->args.offset); |
| } |
| |
| if (put_dreq(dreq)) |
| nfs_direct_write_complete(dreq, inode); |
| } |
| |
| static void nfs_direct_commit_result(struct rpc_task *task, void *calldata) |
| { |
| struct nfs_write_data *data = calldata; |
| struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req; |
| |
| /* Call the NFS version-specific code */ |
| if (NFS_PROTO(data->inode)->commit_done(task, data) != 0) |
| return; |
| if (unlikely(task->tk_status < 0)) { |
| dreq->error = task->tk_status; |
| dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
| } |
| if (memcmp(&dreq->verf, &data->verf, sizeof(data->verf))) { |
| dprintk("NFS: %5u commit verify failed\n", task->tk_pid); |
| dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
| } |
| |
| dprintk("NFS: %5u commit returned %d\n", task->tk_pid, task->tk_status); |
| nfs_direct_write_complete(dreq, data->inode); |
| } |
| |
| static const struct rpc_call_ops nfs_commit_direct_ops = { |
| .rpc_call_done = nfs_direct_commit_result, |
| .rpc_release = nfs_commit_release, |
| }; |
| |
| static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq) |
| { |
| struct nfs_write_data *data = dreq->commit_data; |
| |
| data->inode = dreq->inode; |
| data->cred = dreq->ctx->cred; |
| |
| data->args.fh = NFS_FH(data->inode); |
| data->args.offset = 0; |
| data->args.count = 0; |
| data->res.count = 0; |
| data->res.fattr = &data->fattr; |
| data->res.verf = &data->verf; |
| |
| rpc_init_task(&data->task, NFS_CLIENT(dreq->inode), RPC_TASK_ASYNC, |
| &nfs_commit_direct_ops, data); |
| NFS_PROTO(data->inode)->commit_setup(data, 0); |
| |
| data->task.tk_priority = RPC_PRIORITY_NORMAL; |
| data->task.tk_cookie = (unsigned long)data->inode; |
| /* Note: task.tk_ops->rpc_release will free dreq->commit_data */ |
| dreq->commit_data = NULL; |
| |
| dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid); |
| |
| lock_kernel(); |
| rpc_execute(&data->task); |
| unlock_kernel(); |
| } |
| |
| static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode) |
| { |
| int flags = dreq->flags; |
| |
| dreq->flags = 0; |
| switch (flags) { |
| case NFS_ODIRECT_DO_COMMIT: |
| nfs_direct_commit_schedule(dreq); |
| break; |
| case NFS_ODIRECT_RESCHED_WRITES: |
| nfs_direct_write_reschedule(dreq); |
| break; |
| default: |
| nfs_end_data_update(inode); |
| if (dreq->commit_data != NULL) |
| nfs_commit_free(dreq->commit_data); |
| nfs_direct_free_writedata(dreq); |
| nfs_direct_complete(dreq); |
| } |
| } |
| |
| static void nfs_alloc_commit_data(struct nfs_direct_req *dreq) |
| { |
| dreq->commit_data = nfs_commit_alloc(0); |
| if (dreq->commit_data != NULL) |
| dreq->commit_data->req = (struct nfs_page *) dreq; |
| } |
| #else |
| static inline void nfs_alloc_commit_data(struct nfs_direct_req *dreq) |
| { |
| dreq->commit_data = NULL; |
| } |
| |
| static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode) |
| { |
| nfs_end_data_update(inode); |
| nfs_direct_free_writedata(dreq); |
| nfs_direct_complete(dreq); |
| } |
| #endif |
| |
| static struct nfs_direct_req *nfs_direct_write_alloc(size_t nbytes, size_t wsize) |
| { |
| struct list_head *list; |
| struct nfs_direct_req *dreq; |
| unsigned int wpages = (wsize + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
| |
| dreq = nfs_direct_req_alloc(); |
| if (!dreq) |
| return NULL; |
| |
| list = &dreq->list; |
| for(;;) { |
| struct nfs_write_data *data = nfs_writedata_alloc(wpages); |
| |
| if (unlikely(!data)) { |
| while (!list_empty(list)) { |
| data = list_entry(list->next, |
| struct nfs_write_data, pages); |
| list_del(&data->pages); |
| nfs_writedata_free(data); |
| } |
| kref_put(&dreq->kref, nfs_direct_req_release); |
| return NULL; |
| } |
| |
| INIT_LIST_HEAD(&data->pages); |
| list_add(&data->pages, list); |
| |
| data->req = (struct nfs_page *) dreq; |
| get_dreq(dreq); |
| if (nbytes <= wsize) |
| break; |
| nbytes -= wsize; |
| } |
| |
| nfs_alloc_commit_data(dreq); |
| |
| kref_get(&dreq->kref); |
| return dreq; |
| } |
| |
| static void nfs_direct_write_result(struct rpc_task *task, void *calldata) |
| { |
| struct nfs_write_data *data = calldata; |
| struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req; |
| int status = task->tk_status; |
| |
| if (nfs_writeback_done(task, data) != 0) |
| return; |
| |
| spin_lock(&dreq->lock); |
| |
| if (likely(status >= 0)) |
| dreq->count += data->res.count; |
| else |
| dreq->error = task->tk_status; |
| |
| if (data->res.verf->committed != NFS_FILE_SYNC) { |
| switch (dreq->flags) { |
| case 0: |
| memcpy(&dreq->verf, &data->verf, sizeof(dreq->verf)); |
| dreq->flags = NFS_ODIRECT_DO_COMMIT; |
| break; |
| case NFS_ODIRECT_DO_COMMIT: |
| if (memcmp(&dreq->verf, &data->verf, sizeof(dreq->verf))) { |
| dprintk("NFS: %5u write verify failed\n", task->tk_pid); |
| dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
| } |
| } |
| } |
| |
| spin_unlock(&dreq->lock); |
| } |
| |
| /* |
| * NB: Return the value of the first error return code. Subsequent |
| * errors after the first one are ignored. |
| */ |
| static void nfs_direct_write_release(void *calldata) |
| { |
| struct nfs_write_data *data = calldata; |
| struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req; |
| |
| if (put_dreq(dreq)) |
| nfs_direct_write_complete(dreq, data->inode); |
| } |
| |
| static const struct rpc_call_ops nfs_write_direct_ops = { |
| .rpc_call_done = nfs_direct_write_result, |
| .rpc_release = nfs_direct_write_release, |
| }; |
| |
| /* |
| * For each nfs_write_data struct that was allocated on the list, dispatch |
| * an NFS WRITE operation. If get_user_pages() fails, we stop sending writes. |
| * Write length accounting is handled by nfs_direct_write_result(). |
| * Otherwise, if no requests have been sent, just return an error. |
| */ |
| static ssize_t nfs_direct_write_schedule(struct nfs_direct_req *dreq, unsigned long user_addr, size_t count, loff_t pos, int sync) |
| { |
| struct nfs_open_context *ctx = dreq->ctx; |
| struct inode *inode = ctx->dentry->d_inode; |
| struct list_head *list = &dreq->list; |
| size_t wsize = NFS_SERVER(inode)->wsize; |
| unsigned int pgbase; |
| int result; |
| ssize_t started = 0; |
| struct nfs_write_data *data; |
| |
| pgbase = user_addr & ~PAGE_MASK; |
| do { |
| size_t bytes; |
| |
| bytes = wsize; |
| if (count < wsize) |
| bytes = count; |
| |
| BUG_ON(list_empty(list)); |
| data = list_entry(list->next, struct nfs_write_data, pages); |
| |
| data->npages = nfs_direct_count_pages(user_addr, bytes); |
| down_read(¤t->mm->mmap_sem); |
| result = get_user_pages(current, current->mm, user_addr, |
| data->npages, 0, 0, data->pagevec, NULL); |
| up_read(¤t->mm->mmap_sem); |
| if (unlikely(result < data->npages)) |
| goto out_err; |
| |
| list_move_tail(&data->pages, &dreq->rewrite_list); |
| |
| data->inode = inode; |
| data->cred = ctx->cred; |
| data->args.fh = NFS_FH(inode); |
| data->args.context = ctx; |
| data->args.offset = pos; |
| data->args.pgbase = pgbase; |
| data->args.pages = data->pagevec; |
| data->args.count = bytes; |
| data->res.fattr = &data->fattr; |
| data->res.count = bytes; |
| data->res.verf = &data->verf; |
| |
| rpc_init_task(&data->task, NFS_CLIENT(inode), RPC_TASK_ASYNC, |
| &nfs_write_direct_ops, data); |
| NFS_PROTO(inode)->write_setup(data, sync); |
| |
| data->task.tk_priority = RPC_PRIORITY_NORMAL; |
| data->task.tk_cookie = (unsigned long) inode; |
| |
| lock_kernel(); |
| rpc_execute(&data->task); |
| unlock_kernel(); |
| |
| dfprintk(VFS, "NFS: %5u initiated direct write call (req %s/%Ld, %zu bytes @ offset %Lu)\n", |
| data->task.tk_pid, |
| inode->i_sb->s_id, |
| (long long)NFS_FILEID(inode), |
| bytes, |
| (unsigned long long)data->args.offset); |
| |
| started += bytes; |
| user_addr += bytes; |
| pos += bytes; |
| pgbase += bytes; |
| pgbase &= ~PAGE_MASK; |
| |
| count -= bytes; |
| } while (count != 0); |
| BUG_ON(!list_empty(list)); |
| return 0; |
| |
| out_err: |
| if (result > 0) |
| nfs_direct_release_pages(data->pagevec, result); |
| |
| list_add(&data->pages, list); |
| while (!list_empty(list)) { |
| data = list_entry(list->next, struct nfs_write_data, pages); |
| list_del(&data->pages); |
| nfs_writedata_free(data); |
| if (put_dreq(dreq)) |
| nfs_direct_write_complete(dreq, inode); |
| } |
| |
| if (started) |
| return 0; |
| return result < 0 ? (ssize_t) result : -EFAULT; |
| } |
| |
| static ssize_t nfs_direct_write(struct kiocb *iocb, unsigned long user_addr, size_t count, loff_t pos) |
| { |
| ssize_t result; |
| sigset_t oldset; |
| struct inode *inode = iocb->ki_filp->f_mapping->host; |
| struct rpc_clnt *clnt = NFS_CLIENT(inode); |
| struct nfs_direct_req *dreq; |
| size_t wsize = NFS_SERVER(inode)->wsize; |
| int sync = 0; |
| |
| dreq = nfs_direct_write_alloc(count, wsize); |
| if (!dreq) |
| return -ENOMEM; |
| if (dreq->commit_data == NULL || count < wsize) |
| sync = FLUSH_STABLE; |
| |
| dreq->inode = inode; |
| dreq->ctx = get_nfs_open_context((struct nfs_open_context *)iocb->ki_filp->private_data); |
| if (!is_sync_kiocb(iocb)) |
| dreq->iocb = iocb; |
| |
| nfs_add_stats(inode, NFSIOS_DIRECTWRITTENBYTES, count); |
| |
| nfs_begin_data_update(inode); |
| |
| rpc_clnt_sigmask(clnt, &oldset); |
| result = nfs_direct_write_schedule(dreq, user_addr, count, pos, sync); |
| if (!result) |
| result = nfs_direct_wait(dreq); |
| rpc_clnt_sigunmask(clnt, &oldset); |
| |
| return result; |
| } |
| |
| /** |
| * nfs_file_direct_read - file direct read operation for NFS files |
| * @iocb: target I/O control block |
| * @buf: user's buffer into which to read data |
| * @count: number of bytes to read |
| * @pos: byte offset in file where reading starts |
| * |
| * We use this function for direct reads instead of calling |
| * generic_file_aio_read() in order to avoid gfar's check to see if |
| * the request starts before the end of the file. For that check |
| * to work, we must generate a GETATTR before each direct read, and |
| * even then there is a window between the GETATTR and the subsequent |
| * READ where the file size could change. Our preference is simply |
| * to do all reads the application wants, and the server will take |
| * care of managing the end of file boundary. |
| * |
| * This function also eliminates unnecessarily updating the file's |
| * atime locally, as the NFS server sets the file's atime, and this |
| * client must read the updated atime from the server back into its |
| * cache. |
| */ |
| ssize_t nfs_file_direct_read(struct kiocb *iocb, char __user *buf, size_t count, loff_t pos) |
| { |
| ssize_t retval = -EINVAL; |
| struct file *file = iocb->ki_filp; |
| struct address_space *mapping = file->f_mapping; |
| |
| dprintk("nfs: direct read(%s/%s, %lu@%Ld)\n", |
| file->f_dentry->d_parent->d_name.name, |
| file->f_dentry->d_name.name, |
| (unsigned long) count, (long long) pos); |
| |
| if (count < 0) |
| goto out; |
| retval = -EFAULT; |
| if (!access_ok(VERIFY_WRITE, buf, count)) |
| goto out; |
| retval = 0; |
| if (!count) |
| goto out; |
| |
| retval = nfs_sync_mapping(mapping); |
| if (retval) |
| goto out; |
| |
| retval = nfs_direct_read(iocb, (unsigned long) buf, count, pos); |
| if (retval > 0) |
| iocb->ki_pos = pos + retval; |
| |
| out: |
| return retval; |
| } |
| |
| /** |
| * nfs_file_direct_write - file direct write operation for NFS files |
| * @iocb: target I/O control block |
| * @buf: user's buffer from which to write data |
| * @count: number of bytes to write |
| * @pos: byte offset in file where writing starts |
| * |
| * We use this function for direct writes instead of calling |
| * generic_file_aio_write() in order to avoid taking the inode |
| * semaphore and updating the i_size. The NFS server will set |
| * the new i_size and this client must read the updated size |
| * back into its cache. We let the server do generic write |
| * parameter checking and report problems. |
| * |
| * We also avoid an unnecessary invocation of generic_osync_inode(), |
| * as it is fairly meaningless to sync the metadata of an NFS file. |
| * |
| * We eliminate local atime updates, see direct read above. |
| * |
| * We avoid unnecessary page cache invalidations for normal cached |
| * readers of this file. |
| * |
| * Note that O_APPEND is not supported for NFS direct writes, as there |
| * is no atomic O_APPEND write facility in the NFS protocol. |
| */ |
| ssize_t nfs_file_direct_write(struct kiocb *iocb, const char __user *buf, size_t count, loff_t pos) |
| { |
| ssize_t retval; |
| struct file *file = iocb->ki_filp; |
| struct address_space *mapping = file->f_mapping; |
| |
| dfprintk(VFS, "nfs: direct write(%s/%s, %lu@%Ld)\n", |
| file->f_dentry->d_parent->d_name.name, |
| file->f_dentry->d_name.name, |
| (unsigned long) count, (long long) pos); |
| |
| retval = generic_write_checks(file, &pos, &count, 0); |
| if (retval) |
| goto out; |
| |
| retval = -EINVAL; |
| if ((ssize_t) count < 0) |
| goto out; |
| retval = 0; |
| if (!count) |
| goto out; |
| |
| retval = -EFAULT; |
| if (!access_ok(VERIFY_READ, buf, count)) |
| goto out; |
| |
| retval = nfs_sync_mapping(mapping); |
| if (retval) |
| goto out; |
| |
| retval = nfs_direct_write(iocb, (unsigned long) buf, count, pos); |
| |
| /* |
| * XXX: nfs_end_data_update() already ensures this file's |
| * cached data is subsequently invalidated. Do we really |
| * need to call invalidate_inode_pages2() again here? |
| * |
| * For aio writes, this invalidation will almost certainly |
| * occur before the writes complete. Kind of racey. |
| */ |
| if (mapping->nrpages) |
| invalidate_inode_pages2(mapping); |
| |
| if (retval > 0) |
| iocb->ki_pos = pos + retval; |
| |
| out: |
| return retval; |
| } |
| |
| /** |
| * nfs_init_directcache - create a slab cache for nfs_direct_req structures |
| * |
| */ |
| int __init nfs_init_directcache(void) |
| { |
| nfs_direct_cachep = kmem_cache_create("nfs_direct_cache", |
| sizeof(struct nfs_direct_req), |
| 0, (SLAB_RECLAIM_ACCOUNT| |
| SLAB_MEM_SPREAD), |
| NULL, NULL); |
| if (nfs_direct_cachep == NULL) |
| return -ENOMEM; |
| |
| return 0; |
| } |
| |
| /** |
| * nfs_destroy_directcache - destroy the slab cache for nfs_direct_req structures |
| * |
| */ |
| void __exit nfs_destroy_directcache(void) |
| { |
| if (kmem_cache_destroy(nfs_direct_cachep)) |
| printk(KERN_INFO "nfs_direct_cache: not all structures were freed\n"); |
| } |