1010 lines
26 KiB
C
1010 lines
26 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/fs/nfs/direct.c
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*
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* Copyright (C) 2003 by Chuck Lever <cel@netapp.com>
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*
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* High-performance uncached I/O for the Linux NFS client
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*
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* There are important applications whose performance or correctness
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* depends on uncached access to file data. Database clusters
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* (multiple copies of the same instance running on separate hosts)
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* implement their own cache coherency protocol that subsumes file
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* system cache protocols. Applications that process datasets
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* considerably larger than the client's memory do not always benefit
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* from a local cache. A streaming video server, for instance, has no
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* need to cache the contents of a file.
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*
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* When an application requests uncached I/O, all read and write requests
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* are made directly to the server; data stored or fetched via these
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* requests is not cached in the Linux page cache. The client does not
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* correct unaligned requests from applications. All requested bytes are
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* held on permanent storage before a direct write system call returns to
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* an application.
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*
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* Solaris implements an uncached I/O facility called directio() that
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* is used for backups and sequential I/O to very large files. Solaris
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* also supports uncaching whole NFS partitions with "-o forcedirectio,"
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* an undocumented mount option.
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*
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* Designed by Jeff Kimmel, Chuck Lever, and Trond Myklebust, with
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* help from Andrew Morton.
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*
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* 18 Dec 2001 Initial implementation for 2.4 --cel
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* 08 Jul 2002 Version for 2.4.19, with bug fixes --trondmy
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* 08 Jun 2003 Port to 2.5 APIs --cel
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* 31 Mar 2004 Handle direct I/O without VFS support --cel
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* 15 Sep 2004 Parallel async reads --cel
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* 04 May 2005 support O_DIRECT with aio --cel
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*
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*/
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/file.h>
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#include <linux/pagemap.h>
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#include <linux/kref.h>
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#include <linux/slab.h>
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#include <linux/task_io_accounting_ops.h>
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#include <linux/module.h>
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#include <linux/nfs_fs.h>
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#include <linux/nfs_page.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/uaccess.h>
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#include <linux/atomic.h>
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#include "internal.h"
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#include "iostat.h"
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#include "pnfs.h"
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#include "fscache.h"
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#include "nfstrace.h"
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#define NFSDBG_FACILITY NFSDBG_VFS
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static struct kmem_cache *nfs_direct_cachep;
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static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops;
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static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops;
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static void nfs_direct_write_complete(struct nfs_direct_req *dreq);
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static void nfs_direct_write_schedule_work(struct work_struct *work);
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static inline void get_dreq(struct nfs_direct_req *dreq)
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{
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atomic_inc(&dreq->io_count);
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}
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static inline int put_dreq(struct nfs_direct_req *dreq)
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{
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return atomic_dec_and_test(&dreq->io_count);
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}
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static void
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nfs_direct_handle_truncated(struct nfs_direct_req *dreq,
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const struct nfs_pgio_header *hdr,
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ssize_t dreq_len)
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{
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if (!(test_bit(NFS_IOHDR_ERROR, &hdr->flags) ||
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test_bit(NFS_IOHDR_EOF, &hdr->flags)))
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return;
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if (dreq->max_count >= dreq_len) {
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dreq->max_count = dreq_len;
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if (dreq->count > dreq_len)
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dreq->count = dreq_len;
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if (test_bit(NFS_IOHDR_ERROR, &hdr->flags))
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dreq->error = hdr->error;
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else /* Clear outstanding error if this is EOF */
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dreq->error = 0;
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}
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}
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static void
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nfs_direct_count_bytes(struct nfs_direct_req *dreq,
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const struct nfs_pgio_header *hdr)
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{
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loff_t hdr_end = hdr->io_start + hdr->good_bytes;
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ssize_t dreq_len = 0;
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if (hdr_end > dreq->io_start)
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dreq_len = hdr_end - dreq->io_start;
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nfs_direct_handle_truncated(dreq, hdr, dreq_len);
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if (dreq_len > dreq->max_count)
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dreq_len = dreq->max_count;
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if (dreq->count < dreq_len)
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dreq->count = dreq_len;
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}
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/**
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* nfs_swap_rw - NFS address space operation for swap I/O
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* @iocb: target I/O control block
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* @iter: I/O buffer
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*
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* Perform IO to the swap-file. This is much like direct IO.
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*/
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int nfs_swap_rw(struct kiocb *iocb, struct iov_iter *iter)
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{
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ssize_t ret;
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VM_BUG_ON(iov_iter_count(iter) != PAGE_SIZE);
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if (iov_iter_rw(iter) == READ)
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ret = nfs_file_direct_read(iocb, iter, true);
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else
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ret = nfs_file_direct_write(iocb, iter, true);
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if (ret < 0)
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return ret;
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return 0;
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}
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static void nfs_direct_release_pages(struct page **pages, unsigned int npages)
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{
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unsigned int i;
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for (i = 0; i < npages; i++)
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put_page(pages[i]);
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}
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void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo,
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struct nfs_direct_req *dreq)
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{
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cinfo->inode = dreq->inode;
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cinfo->mds = &dreq->mds_cinfo;
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cinfo->ds = &dreq->ds_cinfo;
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cinfo->dreq = dreq;
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cinfo->completion_ops = &nfs_direct_commit_completion_ops;
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}
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static inline struct nfs_direct_req *nfs_direct_req_alloc(void)
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{
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struct nfs_direct_req *dreq;
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dreq = kmem_cache_zalloc(nfs_direct_cachep, GFP_KERNEL);
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if (!dreq)
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return NULL;
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kref_init(&dreq->kref);
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kref_get(&dreq->kref);
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init_completion(&dreq->completion);
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INIT_LIST_HEAD(&dreq->mds_cinfo.list);
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pnfs_init_ds_commit_info(&dreq->ds_cinfo);
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INIT_WORK(&dreq->work, nfs_direct_write_schedule_work);
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spin_lock_init(&dreq->lock);
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return dreq;
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}
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static void nfs_direct_req_free(struct kref *kref)
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{
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struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref);
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pnfs_release_ds_info(&dreq->ds_cinfo, dreq->inode);
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if (dreq->l_ctx != NULL)
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nfs_put_lock_context(dreq->l_ctx);
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if (dreq->ctx != NULL)
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put_nfs_open_context(dreq->ctx);
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kmem_cache_free(nfs_direct_cachep, dreq);
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}
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static void nfs_direct_req_release(struct nfs_direct_req *dreq)
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{
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kref_put(&dreq->kref, nfs_direct_req_free);
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}
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ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq)
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{
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return dreq->bytes_left;
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}
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EXPORT_SYMBOL_GPL(nfs_dreq_bytes_left);
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/*
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* Collects and returns the final error value/byte-count.
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*/
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static ssize_t nfs_direct_wait(struct nfs_direct_req *dreq)
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{
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ssize_t result = -EIOCBQUEUED;
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/* Async requests don't wait here */
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if (dreq->iocb)
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goto out;
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result = wait_for_completion_killable(&dreq->completion);
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if (!result) {
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result = dreq->count;
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WARN_ON_ONCE(dreq->count < 0);
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}
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if (!result)
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result = dreq->error;
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out:
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return (ssize_t) result;
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}
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/*
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* Synchronous I/O uses a stack-allocated iocb. Thus we can't trust
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* the iocb is still valid here if this is a synchronous request.
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*/
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static void nfs_direct_complete(struct nfs_direct_req *dreq)
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{
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struct inode *inode = dreq->inode;
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inode_dio_end(inode);
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if (dreq->iocb) {
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long res = (long) dreq->error;
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if (dreq->count != 0) {
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res = (long) dreq->count;
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WARN_ON_ONCE(dreq->count < 0);
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}
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dreq->iocb->ki_complete(dreq->iocb, res);
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}
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complete(&dreq->completion);
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nfs_direct_req_release(dreq);
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}
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static void nfs_direct_read_completion(struct nfs_pgio_header *hdr)
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{
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unsigned long bytes = 0;
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struct nfs_direct_req *dreq = hdr->dreq;
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spin_lock(&dreq->lock);
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if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) {
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spin_unlock(&dreq->lock);
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goto out_put;
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}
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nfs_direct_count_bytes(dreq, hdr);
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spin_unlock(&dreq->lock);
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while (!list_empty(&hdr->pages)) {
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struct nfs_page *req = nfs_list_entry(hdr->pages.next);
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struct page *page = req->wb_page;
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if (!PageCompound(page) && bytes < hdr->good_bytes &&
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(dreq->flags == NFS_ODIRECT_SHOULD_DIRTY))
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set_page_dirty(page);
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bytes += req->wb_bytes;
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nfs_list_remove_request(req);
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nfs_release_request(req);
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}
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out_put:
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if (put_dreq(dreq))
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nfs_direct_complete(dreq);
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hdr->release(hdr);
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}
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static void nfs_read_sync_pgio_error(struct list_head *head, int error)
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{
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struct nfs_page *req;
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while (!list_empty(head)) {
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req = nfs_list_entry(head->next);
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nfs_list_remove_request(req);
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nfs_release_request(req);
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}
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}
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static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr)
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{
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get_dreq(hdr->dreq);
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}
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static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = {
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.error_cleanup = nfs_read_sync_pgio_error,
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.init_hdr = nfs_direct_pgio_init,
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.completion = nfs_direct_read_completion,
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};
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/*
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* For each rsize'd chunk of the user's buffer, dispatch an NFS READ
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* operation. If nfs_readdata_alloc() or get_user_pages() fails,
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* bail and stop sending more reads. Read length accounting is
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* handled automatically by nfs_direct_read_result(). Otherwise, if
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* no requests have been sent, just return an error.
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*/
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static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
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struct iov_iter *iter,
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loff_t pos)
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{
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struct nfs_pageio_descriptor desc;
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struct inode *inode = dreq->inode;
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ssize_t result = -EINVAL;
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size_t requested_bytes = 0;
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size_t rsize = max_t(size_t, NFS_SERVER(inode)->rsize, PAGE_SIZE);
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nfs_pageio_init_read(&desc, dreq->inode, false,
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&nfs_direct_read_completion_ops);
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get_dreq(dreq);
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desc.pg_dreq = dreq;
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inode_dio_begin(inode);
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while (iov_iter_count(iter)) {
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struct page **pagevec;
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size_t bytes;
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size_t pgbase;
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unsigned npages, i;
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result = iov_iter_get_pages_alloc2(iter, &pagevec,
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rsize, &pgbase);
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if (result < 0)
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break;
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bytes = result;
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npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE;
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for (i = 0; i < npages; i++) {
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struct nfs_page *req;
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unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase);
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/* XXX do we need to do the eof zeroing found in async_filler? */
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req = nfs_create_request(dreq->ctx, pagevec[i],
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pgbase, req_len);
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if (IS_ERR(req)) {
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result = PTR_ERR(req);
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break;
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}
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req->wb_index = pos >> PAGE_SHIFT;
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req->wb_offset = pos & ~PAGE_MASK;
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if (!nfs_pageio_add_request(&desc, req)) {
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result = desc.pg_error;
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nfs_release_request(req);
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break;
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}
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pgbase = 0;
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bytes -= req_len;
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requested_bytes += req_len;
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pos += req_len;
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dreq->bytes_left -= req_len;
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}
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nfs_direct_release_pages(pagevec, npages);
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kvfree(pagevec);
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if (result < 0)
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break;
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}
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nfs_pageio_complete(&desc);
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/*
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* If no bytes were started, return the error, and let the
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* generic layer handle the completion.
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*/
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if (requested_bytes == 0) {
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inode_dio_end(inode);
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nfs_direct_req_release(dreq);
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return result < 0 ? result : -EIO;
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}
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if (put_dreq(dreq))
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nfs_direct_complete(dreq);
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return requested_bytes;
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}
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/**
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* nfs_file_direct_read - file direct read operation for NFS files
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* @iocb: target I/O control block
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* @iter: vector of user buffers into which to read data
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* @swap: flag indicating this is swap IO, not O_DIRECT IO
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*
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* We use this function for direct reads instead of calling
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* generic_file_aio_read() in order to avoid gfar's check to see if
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* the request starts before the end of the file. For that check
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* to work, we must generate a GETATTR before each direct read, and
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* even then there is a window between the GETATTR and the subsequent
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* READ where the file size could change. Our preference is simply
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* to do all reads the application wants, and the server will take
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* care of managing the end of file boundary.
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*
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* This function also eliminates unnecessarily updating the file's
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* atime locally, as the NFS server sets the file's atime, and this
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* client must read the updated atime from the server back into its
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* cache.
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*/
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ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter,
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bool swap)
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{
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struct file *file = iocb->ki_filp;
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struct address_space *mapping = file->f_mapping;
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struct inode *inode = mapping->host;
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struct nfs_direct_req *dreq;
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struct nfs_lock_context *l_ctx;
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ssize_t result, requested;
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size_t count = iov_iter_count(iter);
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nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);
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dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n",
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file, count, (long long) iocb->ki_pos);
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result = 0;
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if (!count)
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goto out;
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task_io_account_read(count);
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result = -ENOMEM;
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dreq = nfs_direct_req_alloc();
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if (dreq == NULL)
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goto out;
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|
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dreq->inode = inode;
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dreq->bytes_left = dreq->max_count = count;
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dreq->io_start = iocb->ki_pos;
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dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
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l_ctx = nfs_get_lock_context(dreq->ctx);
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if (IS_ERR(l_ctx)) {
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result = PTR_ERR(l_ctx);
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nfs_direct_req_release(dreq);
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goto out_release;
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}
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dreq->l_ctx = l_ctx;
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if (!is_sync_kiocb(iocb))
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dreq->iocb = iocb;
|
|
|
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if (user_backed_iter(iter))
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dreq->flags = NFS_ODIRECT_SHOULD_DIRTY;
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|
|
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if (!swap)
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nfs_start_io_direct(inode);
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|
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NFS_I(inode)->read_io += count;
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requested = nfs_direct_read_schedule_iovec(dreq, iter, iocb->ki_pos);
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|
|
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if (!swap)
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nfs_end_io_direct(inode);
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|
|
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if (requested > 0) {
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result = nfs_direct_wait(dreq);
|
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if (result > 0) {
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requested -= result;
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iocb->ki_pos += result;
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}
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iov_iter_revert(iter, requested);
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} else {
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result = requested;
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}
|
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|
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out_release:
|
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nfs_direct_req_release(dreq);
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out:
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return result;
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}
|
|
|
|
static void nfs_direct_add_page_head(struct list_head *list,
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struct nfs_page *req)
|
|
{
|
|
struct nfs_page *head = req->wb_head;
|
|
|
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if (!list_empty(&head->wb_list) || !nfs_lock_request(head))
|
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return;
|
|
if (!list_empty(&head->wb_list)) {
|
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nfs_unlock_request(head);
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return;
|
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}
|
|
list_add(&head->wb_list, list);
|
|
kref_get(&head->wb_kref);
|
|
kref_get(&head->wb_kref);
|
|
}
|
|
|
|
static void nfs_direct_join_group(struct list_head *list, struct inode *inode)
|
|
{
|
|
struct nfs_page *req, *subreq;
|
|
|
|
list_for_each_entry(req, list, wb_list) {
|
|
if (req->wb_head != req) {
|
|
nfs_direct_add_page_head(&req->wb_list, req);
|
|
continue;
|
|
}
|
|
subreq = req->wb_this_page;
|
|
if (subreq == req)
|
|
continue;
|
|
do {
|
|
/*
|
|
* Remove subrequests from this list before freeing
|
|
* them in the call to nfs_join_page_group().
|
|
*/
|
|
if (!list_empty(&subreq->wb_list)) {
|
|
nfs_list_remove_request(subreq);
|
|
nfs_release_request(subreq);
|
|
}
|
|
} while ((subreq = subreq->wb_this_page) != req);
|
|
nfs_join_page_group(req, inode);
|
|
}
|
|
}
|
|
|
|
static void
|
|
nfs_direct_write_scan_commit_list(struct inode *inode,
|
|
struct list_head *list,
|
|
struct nfs_commit_info *cinfo)
|
|
{
|
|
mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
|
|
pnfs_recover_commit_reqs(list, cinfo);
|
|
nfs_scan_commit_list(&cinfo->mds->list, list, cinfo, 0);
|
|
mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
|
|
}
|
|
|
|
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);
|
|
nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo);
|
|
|
|
nfs_direct_join_group(&reqs, dreq->inode);
|
|
|
|
dreq->count = 0;
|
|
dreq->max_count = 0;
|
|
list_for_each_entry(req, &reqs, wb_list)
|
|
dreq->max_count += req->wb_bytes;
|
|
nfs_clear_pnfs_ds_commit_verifiers(&dreq->ds_cinfo);
|
|
get_dreq(dreq);
|
|
|
|
nfs_pageio_init_write(&desc, dreq->inode, FLUSH_STABLE, false,
|
|
&nfs_direct_write_completion_ops);
|
|
desc.pg_dreq = dreq;
|
|
|
|
list_for_each_entry_safe(req, tmp, &reqs, wb_list) {
|
|
/* Bump the transmission count */
|
|
req->wb_nio++;
|
|
if (!nfs_pageio_add_request(&desc, req)) {
|
|
nfs_list_move_request(req, &failed);
|
|
spin_lock(&cinfo.inode->i_lock);
|
|
dreq->flags = 0;
|
|
if (desc.pg_error < 0)
|
|
dreq->error = desc.pg_error;
|
|
else
|
|
dreq->error = -EIO;
|
|
spin_unlock(&cinfo.inode->i_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);
|
|
}
|
|
|
|
static void nfs_direct_commit_complete(struct nfs_commit_data *data)
|
|
{
|
|
const struct nfs_writeverf *verf = data->res.verf;
|
|
struct nfs_direct_req *dreq = data->dreq;
|
|
struct nfs_commit_info cinfo;
|
|
struct nfs_page *req;
|
|
int status = data->task.tk_status;
|
|
|
|
trace_nfs_direct_commit_complete(dreq);
|
|
|
|
if (status < 0) {
|
|
/* Errors in commit are fatal */
|
|
dreq->error = status;
|
|
dreq->max_count = 0;
|
|
dreq->count = 0;
|
|
dreq->flags = NFS_ODIRECT_DONE;
|
|
} else {
|
|
status = dreq->error;
|
|
}
|
|
|
|
nfs_init_cinfo_from_dreq(&cinfo, dreq);
|
|
|
|
while (!list_empty(&data->pages)) {
|
|
req = nfs_list_entry(data->pages.next);
|
|
nfs_list_remove_request(req);
|
|
if (status >= 0 && !nfs_write_match_verf(verf, req)) {
|
|
dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
|
|
/*
|
|
* Despite the reboot, the write was successful,
|
|
* so reset wb_nio.
|
|
*/
|
|
req->wb_nio = 0;
|
|
nfs_mark_request_commit(req, NULL, &cinfo, 0);
|
|
} else /* Error or match */
|
|
nfs_release_request(req);
|
|
nfs_unlock_and_release_request(req);
|
|
}
|
|
|
|
if (nfs_commit_end(cinfo.mds))
|
|
nfs_direct_write_complete(dreq);
|
|
}
|
|
|
|
static void nfs_direct_resched_write(struct nfs_commit_info *cinfo,
|
|
struct nfs_page *req)
|
|
{
|
|
struct nfs_direct_req *dreq = cinfo->dreq;
|
|
|
|
trace_nfs_direct_resched_write(dreq);
|
|
|
|
spin_lock(&dreq->lock);
|
|
if (dreq->flags != NFS_ODIRECT_DONE)
|
|
dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
|
|
spin_unlock(&dreq->lock);
|
|
nfs_mark_request_commit(req, NULL, cinfo, 0);
|
|
}
|
|
|
|
static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops = {
|
|
.completion = nfs_direct_commit_complete,
|
|
.resched_write = nfs_direct_resched_write,
|
|
};
|
|
|
|
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_clear_reqs(struct nfs_direct_req *dreq)
|
|
{
|
|
struct nfs_commit_info cinfo;
|
|
struct nfs_page *req;
|
|
LIST_HEAD(reqs);
|
|
|
|
nfs_init_cinfo_from_dreq(&cinfo, dreq);
|
|
nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo);
|
|
|
|
while (!list_empty(&reqs)) {
|
|
req = nfs_list_entry(reqs.next);
|
|
nfs_list_remove_request(req);
|
|
nfs_release_request(req);
|
|
nfs_unlock_and_release_request(req);
|
|
}
|
|
}
|
|
|
|
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_write_clear_reqs(dreq);
|
|
nfs_zap_mapping(dreq->inode, dreq->inode->i_mapping);
|
|
nfs_direct_complete(dreq);
|
|
}
|
|
}
|
|
|
|
static void nfs_direct_write_complete(struct nfs_direct_req *dreq)
|
|
{
|
|
trace_nfs_direct_write_complete(dreq);
|
|
queue_work(nfsiod_workqueue, &dreq->work); /* Calls nfs_direct_write_schedule_work */
|
|
}
|
|
|
|
static void nfs_direct_write_completion(struct nfs_pgio_header *hdr)
|
|
{
|
|
struct nfs_direct_req *dreq = hdr->dreq;
|
|
struct nfs_commit_info cinfo;
|
|
struct nfs_page *req = nfs_list_entry(hdr->pages.next);
|
|
int flags = NFS_ODIRECT_DONE;
|
|
|
|
trace_nfs_direct_write_completion(dreq);
|
|
|
|
nfs_init_cinfo_from_dreq(&cinfo, dreq);
|
|
|
|
spin_lock(&dreq->lock);
|
|
if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) {
|
|
spin_unlock(&dreq->lock);
|
|
goto out_put;
|
|
}
|
|
|
|
nfs_direct_count_bytes(dreq, hdr);
|
|
if (test_bit(NFS_IOHDR_UNSTABLE_WRITES, &hdr->flags)) {
|
|
if (!dreq->flags)
|
|
dreq->flags = NFS_ODIRECT_DO_COMMIT;
|
|
flags = dreq->flags;
|
|
}
|
|
spin_unlock(&dreq->lock);
|
|
|
|
while (!list_empty(&hdr->pages)) {
|
|
|
|
req = nfs_list_entry(hdr->pages.next);
|
|
nfs_list_remove_request(req);
|
|
if (flags == NFS_ODIRECT_DO_COMMIT) {
|
|
kref_get(&req->wb_kref);
|
|
memcpy(&req->wb_verf, &hdr->verf.verifier,
|
|
sizeof(req->wb_verf));
|
|
nfs_mark_request_commit(req, hdr->lseg, &cinfo,
|
|
hdr->ds_commit_idx);
|
|
} else if (flags == NFS_ODIRECT_RESCHED_WRITES) {
|
|
kref_get(&req->wb_kref);
|
|
nfs_mark_request_commit(req, NULL, &cinfo, 0);
|
|
}
|
|
nfs_unlock_and_release_request(req);
|
|
}
|
|
|
|
out_put:
|
|
if (put_dreq(dreq))
|
|
nfs_direct_write_complete(dreq);
|
|
hdr->release(hdr);
|
|
}
|
|
|
|
static void nfs_write_sync_pgio_error(struct list_head *head, int error)
|
|
{
|
|
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 void nfs_direct_write_reschedule_io(struct nfs_pgio_header *hdr)
|
|
{
|
|
struct nfs_direct_req *dreq = hdr->dreq;
|
|
|
|
trace_nfs_direct_write_reschedule_io(dreq);
|
|
|
|
spin_lock(&dreq->lock);
|
|
if (dreq->error == 0) {
|
|
dreq->flags = NFS_ODIRECT_RESCHED_WRITES;
|
|
/* fake unstable write to let common nfs resend pages */
|
|
hdr->verf.committed = NFS_UNSTABLE;
|
|
hdr->good_bytes = hdr->args.offset + hdr->args.count -
|
|
hdr->io_start;
|
|
}
|
|
spin_unlock(&dreq->lock);
|
|
}
|
|
|
|
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,
|
|
.reschedule_io = nfs_direct_write_reschedule_io,
|
|
};
|
|
|
|
|
|
/*
|
|
* 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_iovec(struct nfs_direct_req *dreq,
|
|
struct iov_iter *iter,
|
|
loff_t pos, int ioflags)
|
|
{
|
|
struct nfs_pageio_descriptor desc;
|
|
struct inode *inode = dreq->inode;
|
|
ssize_t result = 0;
|
|
size_t requested_bytes = 0;
|
|
size_t wsize = max_t(size_t, NFS_SERVER(inode)->wsize, PAGE_SIZE);
|
|
|
|
trace_nfs_direct_write_schedule_iovec(dreq);
|
|
|
|
nfs_pageio_init_write(&desc, inode, ioflags, false,
|
|
&nfs_direct_write_completion_ops);
|
|
desc.pg_dreq = dreq;
|
|
get_dreq(dreq);
|
|
inode_dio_begin(inode);
|
|
|
|
NFS_I(inode)->write_io += iov_iter_count(iter);
|
|
while (iov_iter_count(iter)) {
|
|
struct page **pagevec;
|
|
size_t bytes;
|
|
size_t pgbase;
|
|
unsigned npages, i;
|
|
|
|
result = iov_iter_get_pages_alloc2(iter, &pagevec,
|
|
wsize, &pgbase);
|
|
if (result < 0)
|
|
break;
|
|
|
|
bytes = result;
|
|
npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE;
|
|
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, pagevec[i],
|
|
pgbase, req_len);
|
|
if (IS_ERR(req)) {
|
|
result = PTR_ERR(req);
|
|
break;
|
|
}
|
|
|
|
if (desc.pg_error < 0) {
|
|
nfs_free_request(req);
|
|
result = desc.pg_error;
|
|
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;
|
|
requested_bytes += req_len;
|
|
pos += req_len;
|
|
dreq->bytes_left -= req_len;
|
|
}
|
|
nfs_direct_release_pages(pagevec, npages);
|
|
kvfree(pagevec);
|
|
if (result < 0)
|
|
break;
|
|
}
|
|
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_end(inode);
|
|
nfs_direct_req_release(dreq);
|
|
return result < 0 ? result : -EIO;
|
|
}
|
|
|
|
if (put_dreq(dreq))
|
|
nfs_direct_write_complete(dreq);
|
|
return requested_bytes;
|
|
}
|
|
|
|
/**
|
|
* 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
|
|
* @swap: flag indicating this is swap IO, not O_DIRECT IO
|
|
*
|
|
* 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,
|
|
bool swap)
|
|
{
|
|
ssize_t result, requested;
|
|
size_t count;
|
|
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 pos, end;
|
|
|
|
dfprintk(FILE, "NFS: direct write(%pD2, %zd@%Ld)\n",
|
|
file, iov_iter_count(iter), (long long) iocb->ki_pos);
|
|
|
|
if (swap)
|
|
/* bypass generic checks */
|
|
result = iov_iter_count(iter);
|
|
else
|
|
result = generic_write_checks(iocb, iter);
|
|
if (result <= 0)
|
|
return result;
|
|
count = result;
|
|
nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count);
|
|
|
|
pos = iocb->ki_pos;
|
|
end = (pos + iov_iter_count(iter) - 1) >> PAGE_SHIFT;
|
|
|
|
task_io_account_write(count);
|
|
|
|
result = -ENOMEM;
|
|
dreq = nfs_direct_req_alloc();
|
|
if (!dreq)
|
|
goto out;
|
|
|
|
dreq->inode = inode;
|
|
dreq->bytes_left = dreq->max_count = count;
|
|
dreq->io_start = pos;
|
|
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);
|
|
nfs_direct_req_release(dreq);
|
|
goto out_release;
|
|
}
|
|
dreq->l_ctx = l_ctx;
|
|
if (!is_sync_kiocb(iocb))
|
|
dreq->iocb = iocb;
|
|
pnfs_init_ds_commit_info_ops(&dreq->ds_cinfo, inode);
|
|
|
|
if (swap) {
|
|
requested = nfs_direct_write_schedule_iovec(dreq, iter, pos,
|
|
FLUSH_STABLE);
|
|
} else {
|
|
nfs_start_io_direct(inode);
|
|
|
|
requested = nfs_direct_write_schedule_iovec(dreq, iter, pos,
|
|
FLUSH_COND_STABLE);
|
|
|
|
if (mapping->nrpages) {
|
|
invalidate_inode_pages2_range(mapping,
|
|
pos >> PAGE_SHIFT, end);
|
|
}
|
|
|
|
nfs_end_io_direct(inode);
|
|
}
|
|
|
|
if (requested > 0) {
|
|
result = nfs_direct_wait(dreq);
|
|
if (result > 0) {
|
|
requested -= result;
|
|
iocb->ki_pos = pos + result;
|
|
/* XXX: should check the generic_write_sync retval */
|
|
generic_write_sync(iocb, result);
|
|
}
|
|
iov_iter_revert(iter, requested);
|
|
} else {
|
|
result = requested;
|
|
}
|
|
nfs_fscache_invalidate(inode, FSCACHE_INVAL_DIO_WRITE);
|
|
out_release:
|
|
nfs_direct_req_release(dreq);
|
|
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);
|
|
}
|