mirror of https://gitee.com/openkylin/linux.git
999 lines
27 KiB
C
999 lines
27 KiB
C
/*
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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/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 <asm/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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#define NFSDBG_FACILITY NFSDBG_VFS
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static struct kmem_cache *nfs_direct_cachep;
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/*
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* This represents a set of asynchronous requests that we're waiting on
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*/
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struct nfs_direct_req {
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struct kref kref; /* release manager */
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/* I/O parameters */
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struct nfs_open_context *ctx; /* file open context info */
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struct nfs_lock_context *l_ctx; /* Lock context info */
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struct kiocb * iocb; /* controlling i/o request */
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struct inode * inode; /* target file of i/o */
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/* completion state */
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atomic_t io_count; /* i/os we're waiting for */
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spinlock_t lock; /* protect completion state */
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ssize_t count, /* bytes actually processed */
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error; /* any reported error */
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struct completion completion; /* wait for i/o completion */
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/* commit state */
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struct nfs_mds_commit_info mds_cinfo; /* Storage for cinfo */
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struct pnfs_ds_commit_info ds_cinfo; /* Storage for cinfo */
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struct work_struct work;
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int flags;
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#define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */
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#define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */
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struct nfs_writeverf verf; /* unstable write verifier */
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};
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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, struct inode *inode);
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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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/**
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* nfs_direct_IO - NFS address space operation for direct I/O
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* @rw: direction (read or write)
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* @iocb: target I/O control block
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* @iov: array of vectors that define I/O buffer
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* @pos: offset in file to begin the operation
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* @nr_segs: size of iovec array
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*
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* The presence of this routine in the address space ops vector means
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* the NFS client supports direct I/O. However, we shunt off direct
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* read and write requests before the VFS gets them, so this method
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* should never be called.
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*/
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ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs)
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{
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dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n",
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iocb->ki_filp->f_path.dentry->d_name.name,
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(long long) pos, nr_segs);
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return -EINVAL;
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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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page_cache_release(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->lock = &dreq->lock;
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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_alloc(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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dreq->mds_cinfo.ncommit = 0;
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atomic_set(&dreq->mds_cinfo.rpcs_out, 0);
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INIT_LIST_HEAD(&dreq->mds_cinfo.list);
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INIT_WORK(&dreq->work, nfs_direct_write_schedule_work);
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memset(&dreq->ds_cinfo, 0, sizeof(dreq->ds_cinfo));
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dreq->iocb = NULL;
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dreq->ctx = NULL;
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dreq->l_ctx = NULL;
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spin_lock_init(&dreq->lock);
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atomic_set(&dreq->io_count, 0);
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dreq->count = 0;
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dreq->error = 0;
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dreq->flags = 0;
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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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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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/*
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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->error;
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if (!result)
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result = dreq->count;
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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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if (dreq->iocb) {
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long res = (long) dreq->error;
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if (!res)
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res = (long) dreq->count;
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aio_complete(dreq->iocb, res, 0);
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}
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complete_all(&dreq->completion);
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nfs_direct_req_release(dreq);
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}
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void nfs_direct_readpage_release(struct nfs_page *req)
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{
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dprintk("NFS: direct read done (%s/%lld %d@%lld)\n",
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req->wb_context->dentry->d_inode->i_sb->s_id,
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(long long)NFS_FILEID(req->wb_context->dentry->d_inode),
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req->wb_bytes,
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(long long)req_offset(req));
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nfs_release_request(req);
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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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if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
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goto out_put;
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spin_lock(&dreq->lock);
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if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && (hdr->good_bytes == 0))
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dreq->error = hdr->error;
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else
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dreq->count += hdr->good_bytes;
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spin_unlock(&dreq->lock);
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if (!test_bit(NFS_IOHDR_ERROR, &hdr->flags)) {
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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 (test_bit(NFS_IOHDR_EOF, &hdr->flags)) {
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if (bytes > hdr->good_bytes)
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zero_user(page, 0, PAGE_SIZE);
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else if (hdr->good_bytes - bytes < PAGE_SIZE)
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zero_user_segment(page,
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hdr->good_bytes & ~PAGE_MASK,
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PAGE_SIZE);
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}
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bytes += req->wb_bytes;
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nfs_list_remove_request(req);
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nfs_direct_readpage_release(req);
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if (!PageCompound(page))
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set_page_dirty(page);
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page_cache_release(page);
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}
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} else {
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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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if (bytes < hdr->good_bytes)
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if (!PageCompound(req->wb_page))
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set_page_dirty(req->wb_page);
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bytes += req->wb_bytes;
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page_cache_release(req->wb_page);
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nfs_list_remove_request(req);
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nfs_direct_readpage_release(req);
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}
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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_sync_pgio_error(struct list_head *head)
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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_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_segment(struct nfs_pageio_descriptor *desc,
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const struct iovec *iov,
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loff_t pos)
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{
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struct nfs_direct_req *dreq = desc->pg_dreq;
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struct nfs_open_context *ctx = dreq->ctx;
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struct inode *inode = ctx->dentry->d_inode;
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unsigned long user_addr = (unsigned long)iov->iov_base;
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size_t count = iov->iov_len;
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size_t rsize = NFS_SERVER(inode)->rsize;
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unsigned int pgbase;
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int result;
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ssize_t started = 0;
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struct page **pagevec = NULL;
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unsigned int npages;
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do {
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size_t bytes;
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int i;
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pgbase = user_addr & ~PAGE_MASK;
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bytes = min(max(rsize, PAGE_SIZE), count);
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result = -ENOMEM;
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npages = nfs_page_array_len(pgbase, bytes);
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if (!pagevec)
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pagevec = kmalloc(npages * sizeof(struct page *),
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GFP_KERNEL);
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if (!pagevec)
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break;
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down_read(¤t->mm->mmap_sem);
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result = get_user_pages(current, current->mm, user_addr,
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npages, 1, 0, pagevec, NULL);
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up_read(¤t->mm->mmap_sem);
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if (result < 0)
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break;
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if ((unsigned)result < npages) {
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bytes = result * PAGE_SIZE;
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if (bytes <= pgbase) {
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nfs_direct_release_pages(pagevec, result);
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break;
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}
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bytes -= pgbase;
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npages = result;
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}
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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(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, dreq->inode,
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pagevec[i],
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pgbase, req_len);
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if (IS_ERR(req)) {
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nfs_direct_release_pages(pagevec + i,
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npages - i);
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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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nfs_direct_release_pages(pagevec + i,
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npages - i);
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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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started += req_len;
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user_addr += req_len;
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pos += req_len;
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count -= req_len;
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}
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} while (count != 0);
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kfree(pagevec);
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if (started)
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return started;
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return result < 0 ? (ssize_t) result : -EFAULT;
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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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const struct iovec *iov,
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unsigned long nr_segs,
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loff_t pos)
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{
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struct nfs_pageio_descriptor desc;
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ssize_t result = -EINVAL;
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size_t requested_bytes = 0;
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unsigned long seg;
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nfs_pageio_init_read(&desc, dreq->inode,
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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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for (seg = 0; seg < nr_segs; seg++) {
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const struct iovec *vec = &iov[seg];
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result = nfs_direct_read_schedule_segment(&desc, vec, pos);
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if (result < 0)
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break;
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requested_bytes += result;
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if ((size_t)result < vec->iov_len)
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break;
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pos += vec->iov_len;
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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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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 0;
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}
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static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos)
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{
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ssize_t result = -ENOMEM;
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struct inode *inode = iocb->ki_filp->f_mapping->host;
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struct nfs_direct_req *dreq;
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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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dreq->inode = inode;
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dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
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dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
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if (dreq->l_ctx == NULL)
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goto out_release;
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if (!is_sync_kiocb(iocb))
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dreq->iocb = iocb;
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result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos);
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if (!result)
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result = nfs_direct_wait(dreq);
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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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}
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#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
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static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq)
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{
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struct nfs_pageio_descriptor desc;
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struct nfs_page *req, *tmp;
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LIST_HEAD(reqs);
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struct nfs_commit_info cinfo;
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LIST_HEAD(failed);
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nfs_init_cinfo_from_dreq(&cinfo, dreq);
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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_pageio_init_write(&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_add_request(req, &failed);
|
|
spin_lock(cinfo.lock);
|
|
dreq->flags = 0;
|
|
dreq->error = -EIO;
|
|
spin_unlock(cinfo.lock);
|
|
}
|
|
}
|
|
nfs_pageio_complete(&desc);
|
|
|
|
while (!list_empty(&failed)) {
|
|
page_cache_release(req->wb_page);
|
|
nfs_release_request(req);
|
|
nfs_unlock_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 {
|
|
page_cache_release(req->wb_page);
|
|
nfs_release_request(req);
|
|
}
|
|
nfs_unlock_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_zap_mapping(dreq->inode, dreq->inode->i_mapping);
|
|
nfs_direct_complete(dreq);
|
|
}
|
|
}
|
|
|
|
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_complete(struct nfs_direct_req *dreq, struct inode *inode)
|
|
{
|
|
nfs_zap_mapping(inode, inode->i_mapping);
|
|
nfs_direct_complete(dreq);
|
|
}
|
|
#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)
|
|
{
|
|
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(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;
|
|
|
|
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;
|
|
|
|
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(bytes, PAGE_SIZE - pgbase);
|
|
|
|
req = nfs_create_request(dreq->ctx, dreq->inode,
|
|
pagevec[i],
|
|
pgbase, req_len);
|
|
if (IS_ERR(req)) {
|
|
nfs_direct_release_pages(pagevec + i,
|
|
npages - i);
|
|
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_request(req);
|
|
nfs_release_request(req);
|
|
nfs_direct_release_pages(pagevec + i,
|
|
npages - i);
|
|
}
|
|
pgbase = 0;
|
|
bytes -= req_len;
|
|
started += req_len;
|
|
user_addr += req_len;
|
|
pos += req_len;
|
|
count -= req_len;
|
|
}
|
|
} while (count != 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, &req->wb_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, &req->wb_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:
|
|
nfs_mark_request_commit(req, hdr->lseg, &cinfo);
|
|
break;
|
|
default:
|
|
page_cache_release(req->wb_page);
|
|
nfs_release_request(req);
|
|
}
|
|
nfs_unlock_request(req);
|
|
}
|
|
|
|
out_put:
|
|
if (put_dreq(dreq))
|
|
nfs_direct_write_complete(dreq, hdr->inode);
|
|
hdr->release(hdr);
|
|
}
|
|
|
|
static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = {
|
|
.error_cleanup = nfs_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,
|
|
const struct iovec *iov,
|
|
unsigned long nr_segs,
|
|
loff_t pos)
|
|
{
|
|
struct nfs_pageio_descriptor desc;
|
|
ssize_t result = 0;
|
|
size_t requested_bytes = 0;
|
|
unsigned long seg;
|
|
|
|
nfs_pageio_init_write(&desc, dreq->inode, FLUSH_COND_STABLE,
|
|
&nfs_direct_write_completion_ops);
|
|
desc.pg_dreq = dreq;
|
|
get_dreq(dreq);
|
|
|
|
for (seg = 0; seg < nr_segs; seg++) {
|
|
const struct iovec *vec = &iov[seg];
|
|
result = nfs_direct_write_schedule_segment(&desc, vec, pos);
|
|
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) {
|
|
nfs_direct_req_release(dreq);
|
|
return result < 0 ? result : -EIO;
|
|
}
|
|
|
|
if (put_dreq(dreq))
|
|
nfs_direct_write_complete(dreq, dreq->inode);
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos,
|
|
size_t count)
|
|
{
|
|
ssize_t result = -ENOMEM;
|
|
struct inode *inode = iocb->ki_filp->f_mapping->host;
|
|
struct nfs_direct_req *dreq;
|
|
|
|
dreq = nfs_direct_req_alloc();
|
|
if (!dreq)
|
|
goto out;
|
|
|
|
dreq->inode = inode;
|
|
dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
|
|
dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
|
|
if (dreq->l_ctx == NULL)
|
|
goto out_release;
|
|
if (!is_sync_kiocb(iocb))
|
|
dreq->iocb = iocb;
|
|
|
|
result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos);
|
|
if (!result)
|
|
result = nfs_direct_wait(dreq);
|
|
out_release:
|
|
nfs_direct_req_release(dreq);
|
|
out:
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* nfs_file_direct_read - file direct read operation for NFS files
|
|
* @iocb: target I/O control block
|
|
* @iov: vector of user buffers into which to read data
|
|
* @nr_segs: size of iov vector
|
|
* @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, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos)
|
|
{
|
|
ssize_t retval = -EINVAL;
|
|
struct file *file = iocb->ki_filp;
|
|
struct address_space *mapping = file->f_mapping;
|
|
size_t count;
|
|
|
|
count = iov_length(iov, nr_segs);
|
|
nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);
|
|
|
|
dfprintk(FILE, "NFS: direct read(%s/%s, %zd@%Ld)\n",
|
|
file->f_path.dentry->d_parent->d_name.name,
|
|
file->f_path.dentry->d_name.name,
|
|
count, (long long) pos);
|
|
|
|
retval = 0;
|
|
if (!count)
|
|
goto out;
|
|
|
|
retval = nfs_sync_mapping(mapping);
|
|
if (retval)
|
|
goto out;
|
|
|
|
task_io_account_read(count);
|
|
|
|
retval = nfs_direct_read(iocb, iov, nr_segs, 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
|
|
* @iov: vector of user buffers from which to write data
|
|
* @nr_segs: size of iov vector
|
|
* @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, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos)
|
|
{
|
|
ssize_t retval = -EINVAL;
|
|
struct file *file = iocb->ki_filp;
|
|
struct address_space *mapping = file->f_mapping;
|
|
size_t count;
|
|
|
|
count = iov_length(iov, nr_segs);
|
|
nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count);
|
|
|
|
dfprintk(FILE, "NFS: direct write(%s/%s, %zd@%Ld)\n",
|
|
file->f_path.dentry->d_parent->d_name.name,
|
|
file->f_path.dentry->d_name.name,
|
|
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 = nfs_sync_mapping(mapping);
|
|
if (retval)
|
|
goto out;
|
|
|
|
task_io_account_write(count);
|
|
|
|
retval = nfs_direct_write(iocb, iov, nr_segs, pos, count);
|
|
if (retval > 0) {
|
|
struct inode *inode = mapping->host;
|
|
|
|
iocb->ki_pos = pos + retval;
|
|
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);
|
|
}
|
|
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);
|
|
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);
|
|
}
|