| /* |
| * 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/errno.h> |
| #include <linux/sched.h> |
| #include <linux/kernel.h> |
| #include <linux/file.h> |
| #include <linux/pagemap.h> |
| #include <linux/kref.h> |
| #include <linux/slab.h> |
| #include <linux/task_io_accounting_ops.h> |
| #include <linux/module.h> |
| |
| #include <linux/nfs_fs.h> |
| #include <linux/nfs_page.h> |
| #include <linux/sunrpc/clnt.h> |
| |
| #include <asm/uaccess.h> |
| #include <linux/atomic.h> |
| |
| #include "internal.h" |
| #include "iostat.h" |
| #include "pnfs.h" |
| |
| #define NFSDBG_FACILITY NFSDBG_VFS |
| |
| static struct kmem_cache *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 nfs_open_context *ctx; /* file open context info */ |
| struct nfs_lock_context *l_ctx; /* Lock 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 */ |
| bytes_left, /* bytes left to be sent */ |
| error; /* any reported error */ |
| struct completion completion; /* wait for i/o completion */ |
| |
| /* commit state */ |
| struct nfs_mds_commit_info mds_cinfo; /* Storage for cinfo */ |
| struct pnfs_ds_commit_info ds_cinfo; /* Storage for cinfo */ |
| struct work_struct work; |
| 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 const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops; |
| static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops; |
| static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode); |
| static void nfs_direct_write_schedule_work(struct work_struct *work); |
| |
| 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); |
| } |
| |
| /** |
| * 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, for most direct IO, we |
| * shunt off direct read and write requests before the VFS gets them, |
| * so this method is only ever called for swap. |
| */ |
| ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, loff_t pos) |
| { |
| #ifndef CONFIG_NFS_SWAP |
| dprintk("NFS: nfs_direct_IO (%pD) off/no(%Ld/%lu) EINVAL\n", |
| iocb->ki_filp, (long long) pos, iter->nr_segs); |
| |
| return -EINVAL; |
| #else |
| VM_BUG_ON(iocb->ki_nbytes != PAGE_SIZE); |
| |
| if (rw == READ || rw == KERNEL_READ) |
| return nfs_file_direct_read(iocb, iter, pos, |
| rw == READ ? true : false); |
| return nfs_file_direct_write(iocb, iter, pos, |
| rw == WRITE ? true : false); |
| #endif /* CONFIG_NFS_SWAP */ |
| } |
| |
| static void nfs_direct_release_pages(struct page **pages, unsigned int npages) |
| { |
| unsigned int i; |
| for (i = 0; i < npages; i++) |
| page_cache_release(pages[i]); |
| } |
| |
| void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo, |
| struct nfs_direct_req *dreq) |
| { |
| cinfo->lock = &dreq->lock; |
| cinfo->mds = &dreq->mds_cinfo; |
| cinfo->ds = &dreq->ds_cinfo; |
| cinfo->dreq = dreq; |
| cinfo->completion_ops = &nfs_direct_commit_completion_ops; |
| } |
| |
| static inline struct nfs_direct_req *nfs_direct_req_alloc(void) |
| { |
| struct nfs_direct_req *dreq; |
| |
| dreq = kmem_cache_zalloc(nfs_direct_cachep, GFP_KERNEL); |
| if (!dreq) |
| return NULL; |
| |
| kref_init(&dreq->kref); |
| kref_get(&dreq->kref); |
| init_completion(&dreq->completion); |
| INIT_LIST_HEAD(&dreq->mds_cinfo.list); |
| INIT_WORK(&dreq->work, nfs_direct_write_schedule_work); |
| spin_lock_init(&dreq->lock); |
| |
| return dreq; |
| } |
| |
| static void nfs_direct_req_free(struct kref *kref) |
| { |
| struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref); |
| |
| if (dreq->l_ctx != NULL) |
| nfs_put_lock_context(dreq->l_ctx); |
| if (dreq->ctx != NULL) |
| put_nfs_open_context(dreq->ctx); |
| kmem_cache_free(nfs_direct_cachep, dreq); |
| } |
| |
| static void nfs_direct_req_release(struct nfs_direct_req *dreq) |
| { |
| kref_put(&dreq->kref, nfs_direct_req_free); |
| } |
| |
| ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq) |
| { |
| return dreq->bytes_left; |
| } |
| EXPORT_SYMBOL_GPL(nfs_dreq_bytes_left); |
| |
| /* |
| * 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_killable(&dreq->completion); |
| |
| if (!result) |
| result = dreq->error; |
| if (!result) |
| result = dreq->count; |
| |
| out: |
| 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, bool write) |
| { |
| struct inode *inode = dreq->inode; |
| |
| if (dreq->iocb && write) { |
| loff_t pos = dreq->iocb->ki_pos + dreq->count; |
| |
| spin_lock(&inode->i_lock); |
| if (i_size_read(inode) < pos) |
| i_size_write(inode, pos); |
| spin_unlock(&inode->i_lock); |
| } |
| |
| if (write) |
| nfs_zap_mapping(inode, inode->i_mapping); |
| |
| inode_dio_done(inode); |
| |
| if (dreq->iocb) { |
| long res = (long) dreq->error; |
| if (!res) |
| res = (long) dreq->count; |
| aio_complete(dreq->iocb, res, 0); |
| } |
| |
| complete_all(&dreq->completion); |
| |
| nfs_direct_req_release(dreq); |
| } |
| |
| static void nfs_direct_readpage_release(struct nfs_page *req) |
| { |
| dprintk("NFS: direct read done (%s/%llu %d@%lld)\n", |
| req->wb_context->dentry->d_inode->i_sb->s_id, |
| (unsigned long long)NFS_FILEID(req->wb_context->dentry->d_inode), |
| req->wb_bytes, |
| (long long)req_offset(req)); |
| nfs_release_request(req); |
| } |
| |
| static void nfs_direct_read_completion(struct nfs_pgio_header *hdr) |
| { |
| unsigned long bytes = 0; |
| struct nfs_direct_req *dreq = hdr->dreq; |
| |
| if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) |
| goto out_put; |
| |
| spin_lock(&dreq->lock); |
| if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && (hdr->good_bytes == 0)) |
| dreq->error = hdr->error; |
| else |
| dreq->count += hdr->good_bytes; |
| spin_unlock(&dreq->lock); |
| |
| while (!list_empty(&hdr->pages)) { |
| struct nfs_page *req = nfs_list_entry(hdr->pages.next); |
| struct page *page = req->wb_page; |
| |
| if (!PageCompound(page) && bytes < hdr->good_bytes) |
| set_page_dirty(page); |
| bytes += req->wb_bytes; |
| nfs_list_remove_request(req); |
| nfs_direct_readpage_release(req); |
| } |
| out_put: |
| if (put_dreq(dreq)) |
| nfs_direct_complete(dreq, false); |
| hdr->release(hdr); |
| } |
| |
| static void nfs_read_sync_pgio_error(struct list_head *head) |
| { |
| struct nfs_page *req; |
| |
| while (!list_empty(head)) { |
| req = nfs_list_entry(head->next); |
| nfs_list_remove_request(req); |
| nfs_release_request(req); |
| } |
| } |
| |
| static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr) |
| { |
| get_dreq(hdr->dreq); |
| } |
| |
| static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = { |
| .error_cleanup = nfs_read_sync_pgio_error, |
| .init_hdr = nfs_direct_pgio_init, |
| .completion = nfs_direct_read_completion, |
| }; |
| |
| /* |
| * For each rsize'd chunk of the user's buffer, dispatch an NFS READ |
| * operation. If nfs_readdata_alloc() or get_user_pages() fails, |
| * bail and stop sending more reads. Read length accounting is |
| * handled automatically by nfs_direct_read_result(). Otherwise, if |
| * no requests have been sent, just return an error. |
| */ |
| static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *desc, |
| const struct iovec *iov, |
| loff_t pos, bool uio) |
| { |
| struct nfs_direct_req *dreq = desc->pg_dreq; |
| struct nfs_open_context *ctx = dreq->ctx; |
| struct inode *inode = ctx->dentry->d_inode; |
| unsigned long user_addr = (unsigned long)iov->iov_base; |
| size_t count = iov->iov_len; |
| size_t rsize = NFS_SERVER(inode)->rsize; |
| unsigned int pgbase; |
| int result; |
| ssize_t started = 0; |
| struct page **pagevec = NULL; |
| unsigned int npages; |
| |
| do { |
| size_t bytes; |
| int i; |
| |
| pgbase = user_addr & ~PAGE_MASK; |
| bytes = min(max_t(size_t, rsize, PAGE_SIZE), count); |
| |
| result = -ENOMEM; |
| npages = nfs_page_array_len(pgbase, bytes); |
| if (!pagevec) |
| pagevec = kmalloc(npages * sizeof(struct page *), |
| GFP_KERNEL); |
| if (!pagevec) |
| break; |
| if (uio) { |
| down_read(¤t->mm->mmap_sem); |
| result = get_user_pages(current, current->mm, user_addr, |
| npages, 1, 0, pagevec, NULL); |
| up_read(¤t->mm->mmap_sem); |
| if (result < 0) |
| break; |
| } else { |
| WARN_ON(npages != 1); |
| result = get_kernel_page(user_addr, 1, pagevec); |
| if (WARN_ON(result != 1)) |
| break; |
| } |
| |
| if ((unsigned)result < npages) { |
| bytes = result * PAGE_SIZE; |
| if (bytes <= pgbase) { |
| nfs_direct_release_pages(pagevec, result); |
| break; |
| } |
| bytes -= pgbase; |
| npages = result; |
| } |
| |
| for (i = 0; i < npages; i++) { |
| struct nfs_page *req; |
| unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); |
| /* XXX do we need to do the eof zeroing found in async_filler? */ |
| req = nfs_create_request(dreq->ctx, dreq->inode, |
| pagevec[i], |
| pgbase, req_len); |
| if (IS_ERR(req)) { |
| result = PTR_ERR(req); |
| break; |
| } |
| req->wb_index = pos >> PAGE_SHIFT; |
| req->wb_offset = pos & ~PAGE_MASK; |
| if (!nfs_pageio_add_request(desc, req)) { |
| result = desc->pg_error; |
| nfs_release_request(req); |
| break; |
| } |
| pgbase = 0; |
| bytes -= req_len; |
| started += req_len; |
| user_addr += req_len; |
| pos += req_len; |
| count -= req_len; |
| dreq->bytes_left -= req_len; |
| } |
| /* The nfs_page now hold references to these pages */ |
| nfs_direct_release_pages(pagevec, npages); |
| } while (count != 0 && result >= 0); |
| |
| kfree(pagevec); |
| |
| if (started) |
| return started; |
| return result < 0 ? (ssize_t) result : -EFAULT; |
| } |
| |
| static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, |
| struct iov_iter *iter, |
| loff_t pos, bool uio) |
| { |
| struct nfs_pageio_descriptor desc; |
| struct inode *inode = dreq->inode; |
| ssize_t result = -EINVAL; |
| size_t requested_bytes = 0; |
| unsigned long seg; |
| |
| NFS_PROTO(dreq->inode)->read_pageio_init(&desc, dreq->inode, |
| &nfs_direct_read_completion_ops); |
| get_dreq(dreq); |
| desc.pg_dreq = dreq; |
| atomic_inc(&inode->i_dio_count); |
| |
| for (seg = 0; seg < iter->nr_segs; seg++) { |
| const struct iovec *vec = &iter->iov[seg]; |
| result = nfs_direct_read_schedule_segment(&desc, vec, pos, uio); |
| if (result < 0) |
| break; |
| requested_bytes += result; |
| if ((size_t)result < vec->iov_len) |
| break; |
| pos += vec->iov_len; |
| } |
| |
| nfs_pageio_complete(&desc); |
| |
| /* |
| * If no bytes were started, return the error, and let the |
| * generic layer handle the completion. |
| */ |
| if (requested_bytes == 0) { |
| inode_dio_done(inode); |
| nfs_direct_req_release(dreq); |
| return result < 0 ? result : -EIO; |
| } |
| |
| if (put_dreq(dreq)) |
| nfs_direct_complete(dreq, false); |
| return 0; |
| } |
| |
| /** |
| * nfs_file_direct_read - file direct read operation for NFS files |
| * @iocb: target I/O control block |
| * @iter: vector of user buffers into which to read data |
| * @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, struct iov_iter *iter, |
| loff_t pos, bool uio) |
| { |
| struct file *file = iocb->ki_filp; |
| struct address_space *mapping = file->f_mapping; |
| struct inode *inode = mapping->host; |
| struct nfs_direct_req *dreq; |
| struct nfs_lock_context *l_ctx; |
| ssize_t result = -EINVAL; |
| size_t count = iov_iter_count(iter); |
| nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count); |
| |
| dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n", |
| file, count, (long long) pos); |
| |
| result = 0; |
| if (!count) |
| goto out; |
| |
| mutex_lock(&inode->i_mutex); |
| result = nfs_sync_mapping(mapping); |
| if (result) |
| goto out_unlock; |
| |
| task_io_account_read(count); |
| |
| result = -ENOMEM; |
| dreq = nfs_direct_req_alloc(); |
| if (dreq == NULL) |
| goto out_unlock; |
| |
| dreq->inode = inode; |
| dreq->bytes_left = count; |
| dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp)); |
| l_ctx = nfs_get_lock_context(dreq->ctx); |
| if (IS_ERR(l_ctx)) { |
| result = PTR_ERR(l_ctx); |
| goto out_release; |
| } |
| dreq->l_ctx = l_ctx; |
| if (!is_sync_kiocb(iocb)) |
| dreq->iocb = iocb; |
| |
| NFS_I(inode)->read_io += count; |
| result = nfs_direct_read_schedule_iovec(dreq, iter, pos, uio); |
| |
| mutex_unlock(&inode->i_mutex); |
| |
| if (!result) { |
| result = nfs_direct_wait(dreq); |
| if (result > 0) |
| iocb->ki_pos = pos + result; |
| } |
| |
| nfs_direct_req_release(dreq); |
| return result; |
| |
| out_release: |
| nfs_direct_req_release(dreq); |
| out_unlock: |
| mutex_unlock(&inode->i_mutex); |
| out: |
| return result; |
| } |
| |
| #if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4) |
| static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq) |
| { |
| struct nfs_pageio_descriptor desc; |
| struct nfs_page *req, *tmp; |
| LIST_HEAD(reqs); |
| struct nfs_commit_info cinfo; |
| LIST_HEAD(failed); |
| |
| nfs_init_cinfo_from_dreq(&cinfo, dreq); |
| pnfs_recover_commit_reqs(dreq->inode, &reqs, &cinfo); |
| spin_lock(cinfo.lock); |
| nfs_scan_commit_list(&cinfo.mds->list, &reqs, &cinfo, 0); |
| spin_unlock(cinfo.lock); |
| |
| dreq->count = 0; |
| get_dreq(dreq); |
| |
| NFS_PROTO(dreq->inode)->write_pageio_init(&desc, dreq->inode, FLUSH_STABLE, |
| &nfs_direct_write_completion_ops); |
| desc.pg_dreq = dreq; |
| |
| list_for_each_entry_safe(req, tmp, &reqs, wb_list) { |
| if (!nfs_pageio_add_request(&desc, req)) { |
| nfs_list_remove_request(req); |
| nfs_list_add_request(req, &failed); |
| spin_lock(cinfo.lock); |
| dreq->flags = 0; |
| dreq->error = -EIO; |
| spin_unlock(cinfo.lock); |
| } |
| nfs_release_request(req); |
| } |
| nfs_pageio_complete(&desc); |
| |
| while (!list_empty(&failed)) { |
| req = nfs_list_entry(failed.next); |
| nfs_list_remove_request(req); |
| nfs_unlock_and_release_request(req); |
| } |
| |
| if (put_dreq(dreq)) |
| nfs_direct_write_complete(dreq, dreq->inode); |
| } |
| |
| static void nfs_direct_commit_complete(struct nfs_commit_data *data) |
| { |
| struct nfs_direct_req *dreq = data->dreq; |
| struct nfs_commit_info cinfo; |
| struct nfs_page *req; |
| int status = data->task.tk_status; |
| |
| nfs_init_cinfo_from_dreq(&cinfo, dreq); |
| if (status < 0) { |
| dprintk("NFS: %5u commit failed with error %d.\n", |
| data->task.tk_pid, status); |
| dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
| } else if (memcmp(&dreq->verf, &data->verf, sizeof(data->verf))) { |
| dprintk("NFS: %5u commit verify failed\n", data->task.tk_pid); |
| dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
| } |
| |
| dprintk("NFS: %5u commit returned %d\n", data->task.tk_pid, status); |
| while (!list_empty(&data->pages)) { |
| req = nfs_list_entry(data->pages.next); |
| nfs_list_remove_request(req); |
| if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES) { |
| /* Note the rewrite will go through mds */ |
| nfs_mark_request_commit(req, NULL, &cinfo); |
| } else |
| nfs_release_request(req); |
| nfs_unlock_and_release_request(req); |
| } |
| |
| if (atomic_dec_and_test(&cinfo.mds->rpcs_out)) |
| nfs_direct_write_complete(dreq, data->inode); |
| } |
| |
| static void nfs_direct_error_cleanup(struct nfs_inode *nfsi) |
| { |
| /* There is no lock to clear */ |
| } |
| |
| static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops = { |
| .completion = nfs_direct_commit_complete, |
| .error_cleanup = nfs_direct_error_cleanup, |
| }; |
| |
| static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq) |
| { |
| int res; |
| struct nfs_commit_info cinfo; |
| LIST_HEAD(mds_list); |
| |
| nfs_init_cinfo_from_dreq(&cinfo, dreq); |
| nfs_scan_commit(dreq->inode, &mds_list, &cinfo); |
| res = nfs_generic_commit_list(dreq->inode, &mds_list, 0, &cinfo); |
| if (res < 0) /* res == -ENOMEM */ |
| nfs_direct_write_reschedule(dreq); |
| } |
| |
| static void nfs_direct_write_schedule_work(struct work_struct *work) |
| { |
| struct nfs_direct_req *dreq = container_of(work, struct nfs_direct_req, work); |
| 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_direct_complete(dreq, true); |
| } |
| } |
| |
| static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode) |
| { |
| schedule_work(&dreq->work); /* Calls nfs_direct_write_schedule_work */ |
| } |
| |
| #else |
| static void nfs_direct_write_schedule_work(struct work_struct *work) |
| { |
| } |
| |
| static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode *inode) |
| { |
| nfs_direct_complete(dreq, true); |
| } |
| #endif |
| |
| /* |
| * NB: Return the value of the first error return code. Subsequent |
| * errors after the first one are ignored. |
| */ |
| /* |
| * For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE |
| * operation. If nfs_writedata_alloc() or get_user_pages() fails, |
| * bail and stop sending more writes. Write length accounting is |
| * handled automatically by nfs_direct_write_result(). Otherwise, if |
| * no requests have been sent, just return an error. |
| */ |
| static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *desc, |
| const struct iovec *iov, |
| loff_t pos, bool uio) |
| { |
| struct nfs_direct_req *dreq = desc->pg_dreq; |
| struct nfs_open_context *ctx = dreq->ctx; |
| struct inode *inode = ctx->dentry->d_inode; |
| unsigned long user_addr = (unsigned long)iov->iov_base; |
| size_t count = iov->iov_len; |
| size_t wsize = NFS_SERVER(inode)->wsize; |
| unsigned int pgbase; |
| int result; |
| ssize_t started = 0; |
| struct page **pagevec = NULL; |
| unsigned int npages; |
| |
| do { |
| size_t bytes; |
| int i; |
| |
| pgbase = user_addr & ~PAGE_MASK; |
| bytes = min(max_t(size_t, wsize, PAGE_SIZE), count); |
| |
| result = -ENOMEM; |
| npages = nfs_page_array_len(pgbase, bytes); |
| if (!pagevec) |
| pagevec = kmalloc(npages * sizeof(struct page *), GFP_KERNEL); |
| if (!pagevec) |
| break; |
| |
| if (uio) { |
| down_read(¤t->mm->mmap_sem); |
| result = get_user_pages(current, current->mm, user_addr, |
| npages, 0, 0, pagevec, NULL); |
| up_read(¤t->mm->mmap_sem); |
| if (result < 0) |
| break; |
| } else { |
| WARN_ON(npages != 1); |
| result = get_kernel_page(user_addr, 0, pagevec); |
| if (WARN_ON(result != 1)) |
| break; |
| } |
| |
| if ((unsigned)result < npages) { |
| bytes = result * PAGE_SIZE; |
| if (bytes <= pgbase) { |
| nfs_direct_release_pages(pagevec, result); |
| break; |
| } |
| bytes -= pgbase; |
| npages = result; |
| } |
| |
| for (i = 0; i < npages; i++) { |
| struct nfs_page *req; |
| unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); |
| |
| req = nfs_create_request(dreq->ctx, dreq->inode, |
| pagevec[i], |
| pgbase, req_len); |
| if (IS_ERR(req)) { |
| result = PTR_ERR(req); |
| break; |
| } |
| nfs_lock_request(req); |
| req->wb_index = pos >> PAGE_SHIFT; |
| req->wb_offset = pos & ~PAGE_MASK; |
| if (!nfs_pageio_add_request(desc, req)) { |
| result = desc->pg_error; |
| nfs_unlock_and_release_request(req); |
| break; |
| } |
| pgbase = 0; |
| bytes -= req_len; |
| started += req_len; |
| user_addr += req_len; |
| pos += req_len; |
| count -= req_len; |
| dreq->bytes_left -= req_len; |
| } |
| /* The nfs_page now hold references to these pages */ |
| nfs_direct_release_pages(pagevec, npages); |
| } while (count != 0 && result >= 0); |
| |
| kfree(pagevec); |
| |
| if (started) |
| return started; |
| return result < 0 ? (ssize_t) result : -EFAULT; |
| } |
| |
| static void nfs_direct_write_completion(struct nfs_pgio_header *hdr) |
| { |
| struct nfs_direct_req *dreq = hdr->dreq; |
| struct nfs_commit_info cinfo; |
| int bit = -1; |
| struct nfs_page *req = nfs_list_entry(hdr->pages.next); |
| |
| if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) |
| goto out_put; |
| |
| nfs_init_cinfo_from_dreq(&cinfo, dreq); |
| |
| spin_lock(&dreq->lock); |
| |
| if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) { |
| dreq->flags = 0; |
| dreq->error = hdr->error; |
| } |
| if (dreq->error != 0) |
| bit = NFS_IOHDR_ERROR; |
| else { |
| dreq->count += hdr->good_bytes; |
| if (test_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags)) { |
| dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
| bit = NFS_IOHDR_NEED_RESCHED; |
| } else if (test_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags)) { |
| if (dreq->flags == NFS_ODIRECT_RESCHED_WRITES) |
| bit = NFS_IOHDR_NEED_RESCHED; |
| else if (dreq->flags == 0) { |
| memcpy(&dreq->verf, hdr->verf, |
| sizeof(dreq->verf)); |
| bit = NFS_IOHDR_NEED_COMMIT; |
| dreq->flags = NFS_ODIRECT_DO_COMMIT; |
| } else if (dreq->flags == NFS_ODIRECT_DO_COMMIT) { |
| if (memcmp(&dreq->verf, hdr->verf, sizeof(dreq->verf))) { |
| dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
| bit = NFS_IOHDR_NEED_RESCHED; |
| } else |
| bit = NFS_IOHDR_NEED_COMMIT; |
| } |
| } |
| } |
| spin_unlock(&dreq->lock); |
| |
| while (!list_empty(&hdr->pages)) { |
| req = nfs_list_entry(hdr->pages.next); |
| nfs_list_remove_request(req); |
| switch (bit) { |
| case NFS_IOHDR_NEED_RESCHED: |
| case NFS_IOHDR_NEED_COMMIT: |
| kref_get(&req->wb_kref); |
| nfs_mark_request_commit(req, hdr->lseg, &cinfo); |
| } |
| nfs_unlock_and_release_request(req); |
| } |
| |
| out_put: |
| if (put_dreq(dreq)) |
| nfs_direct_write_complete(dreq, hdr->inode); |
| hdr->release(hdr); |
| } |
| |
| static void nfs_write_sync_pgio_error(struct list_head *head) |
| { |
| struct nfs_page *req; |
| |
| while (!list_empty(head)) { |
| req = nfs_list_entry(head->next); |
| nfs_list_remove_request(req); |
| nfs_unlock_and_release_request(req); |
| } |
| } |
| |
| static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = { |
| .error_cleanup = nfs_write_sync_pgio_error, |
| .init_hdr = nfs_direct_pgio_init, |
| .completion = nfs_direct_write_completion, |
| }; |
| |
| static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, |
| struct iov_iter *iter, |
| loff_t pos, bool uio) |
| { |
| struct nfs_pageio_descriptor desc; |
| struct inode *inode = dreq->inode; |
| ssize_t result = 0; |
| size_t requested_bytes = 0; |
| unsigned long seg; |
| |
| NFS_PROTO(inode)->write_pageio_init(&desc, inode, FLUSH_COND_STABLE, |
| &nfs_direct_write_completion_ops); |
| desc.pg_dreq = dreq; |
| get_dreq(dreq); |
| atomic_inc(&inode->i_dio_count); |
| |
| NFS_I(dreq->inode)->write_io += iov_iter_count(iter); |
| for (seg = 0; seg < iter->nr_segs; seg++) { |
| const struct iovec *vec = &iter->iov[seg]; |
| result = nfs_direct_write_schedule_segment(&desc, vec, pos, uio); |
| if (result < 0) |
| break; |
| requested_bytes += result; |
| if ((size_t)result < vec->iov_len) |
| break; |
| pos += vec->iov_len; |
| } |
| nfs_pageio_complete(&desc); |
| |
| /* |
| * If no bytes were started, return the error, and let the |
| * generic layer handle the completion. |
| */ |
| if (requested_bytes == 0) { |
| inode_dio_done(inode); |
| nfs_direct_req_release(dreq); |
| return result < 0 ? result : -EIO; |
| } |
| |
| if (put_dreq(dreq)) |
| nfs_direct_write_complete(dreq, dreq->inode); |
| return 0; |
| } |
| |
| /** |
| * nfs_file_direct_write - file direct write operation for NFS files |
| * @iocb: target I/O control block |
| * @iter: vector of user buffers from which to write data |
| * @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 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, struct iov_iter *iter, |
| loff_t pos, bool uio) |
| { |
| ssize_t result = -EINVAL; |
| struct file *file = iocb->ki_filp; |
| struct address_space *mapping = file->f_mapping; |
| struct inode *inode = mapping->host; |
| struct nfs_direct_req *dreq; |
| struct nfs_lock_context *l_ctx; |
| loff_t end; |
| size_t count = iov_iter_count(iter); |
| end = (pos + count - 1) >> PAGE_CACHE_SHIFT; |
| |
| nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count); |
| |
| dfprintk(FILE, "NFS: direct write(%pD2, %zd@%Ld)\n", |
| file, count, (long long) pos); |
| |
| result = generic_write_checks(file, &pos, &count, 0); |
| if (result) |
| goto out; |
| |
| result = -EINVAL; |
| if ((ssize_t) count < 0) |
| goto out; |
| result = 0; |
| if (!count) |
| goto out; |
| |
| mutex_lock(&inode->i_mutex); |
| |
| result = nfs_sync_mapping(mapping); |
| if (result) |
| goto out_unlock; |
| |
| if (mapping->nrpages) { |
| result = invalidate_inode_pages2_range(mapping, |
| pos >> PAGE_CACHE_SHIFT, end); |
| if (result) |
| goto out_unlock; |
| } |
| |
| task_io_account_write(count); |
| |
| result = -ENOMEM; |
| dreq = nfs_direct_req_alloc(); |
| if (!dreq) |
| goto out_unlock; |
| |
| dreq->inode = inode; |
| dreq->bytes_left = count; |
| dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp)); |
| l_ctx = nfs_get_lock_context(dreq->ctx); |
| if (IS_ERR(l_ctx)) { |
| result = PTR_ERR(l_ctx); |
| goto out_release; |
| } |
| dreq->l_ctx = l_ctx; |
| if (!is_sync_kiocb(iocb)) |
| dreq->iocb = iocb; |
| |
| result = nfs_direct_write_schedule_iovec(dreq, iter, pos, uio); |
| |
| if (mapping->nrpages) { |
| invalidate_inode_pages2_range(mapping, |
| pos >> PAGE_CACHE_SHIFT, end); |
| } |
| |
| mutex_unlock(&inode->i_mutex); |
| |
| if (!result) { |
| result = nfs_direct_wait(dreq); |
| if (result > 0) { |
| struct inode *inode = mapping->host; |
| |
| iocb->ki_pos = pos + result; |
| spin_lock(&inode->i_lock); |
| if (i_size_read(inode) < iocb->ki_pos) |
| i_size_write(inode, iocb->ki_pos); |
| spin_unlock(&inode->i_lock); |
| } |
| } |
| nfs_direct_req_release(dreq); |
| return result; |
| |
| out_release: |
| nfs_direct_req_release(dreq); |
| out_unlock: |
| mutex_unlock(&inode->i_mutex); |
| out: |
| return result; |
| } |
| |
| /** |
| * 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); |
| if (nfs_direct_cachep == NULL) |
| return -ENOMEM; |
| |
| return 0; |
| } |
| |
| /** |
| * nfs_destroy_directcache - destroy the slab cache for nfs_direct_req structures |
| * |
| */ |
| void nfs_destroy_directcache(void) |
| { |
| kmem_cache_destroy(nfs_direct_cachep); |
| } |