![Linus Torvalds](/assets/img/avatar_default.png)
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
809 lines
22 KiB
C
809 lines
22 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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*
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*/
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#include <linux/config.h>
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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/smp_lock.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/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/system.h>
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#include <asm/uaccess.h>
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#include <asm/atomic.h>
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#define NFSDBG_FACILITY NFSDBG_VFS
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#define MAX_DIRECTIO_SIZE (4096UL << PAGE_SHIFT)
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static kmem_cache_t *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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struct list_head list; /* nfs_read_data structs */
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wait_queue_head_t wait; /* wait for i/o completion */
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struct page ** pages; /* pages in our buffer */
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unsigned int npages; /* count of pages */
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atomic_t complete, /* i/os we're waiting for */
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count, /* bytes actually processed */
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error; /* any reported error */
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};
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/**
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* nfs_get_user_pages - find and set up pages underlying user's buffer
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* rw: direction (read or write)
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* user_addr: starting address of this segment of user's buffer
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* count: size of this segment
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* @pages: returned array of page struct pointers underlying user's buffer
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*/
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static inline int
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nfs_get_user_pages(int rw, unsigned long user_addr, size_t size,
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struct page ***pages)
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{
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int result = -ENOMEM;
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unsigned long page_count;
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size_t array_size;
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/* set an arbitrary limit to prevent type overflow */
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/* XXX: this can probably be as large as INT_MAX */
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if (size > MAX_DIRECTIO_SIZE) {
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*pages = NULL;
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return -EFBIG;
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}
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page_count = (user_addr + size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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page_count -= user_addr >> PAGE_SHIFT;
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array_size = (page_count * sizeof(struct page *));
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*pages = kmalloc(array_size, GFP_KERNEL);
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if (*pages) {
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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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page_count, (rw == READ), 0,
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*pages, NULL);
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up_read(¤t->mm->mmap_sem);
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}
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return result;
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}
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/**
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* nfs_free_user_pages - tear down page struct array
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* @pages: array of page struct pointers underlying target buffer
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* @npages: number of pages in the array
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* @do_dirty: dirty the pages as we release them
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*/
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static void
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nfs_free_user_pages(struct page **pages, int npages, int do_dirty)
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{
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int i;
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for (i = 0; i < npages; i++) {
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if (do_dirty)
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set_page_dirty_lock(pages[i]);
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page_cache_release(pages[i]);
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}
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kfree(pages);
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}
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/**
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* nfs_direct_req_release - release nfs_direct_req structure for direct read
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* @kref: kref object embedded in an nfs_direct_req structure
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*
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*/
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static void nfs_direct_req_release(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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kmem_cache_free(nfs_direct_cachep, dreq);
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}
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/**
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* nfs_direct_read_alloc - allocate nfs_read_data structures for direct read
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* @count: count of bytes for the read request
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* @rsize: local rsize setting
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*
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* Note we also set the number of requests we have in the dreq when we are
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* done. This prevents races with I/O completion so we will always wait
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* until all requests have been dispatched and completed.
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*/
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static struct nfs_direct_req *nfs_direct_read_alloc(size_t nbytes, unsigned int rsize)
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{
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struct list_head *list;
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struct nfs_direct_req *dreq;
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unsigned int reads = 0;
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dreq = kmem_cache_alloc(nfs_direct_cachep, SLAB_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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init_waitqueue_head(&dreq->wait);
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INIT_LIST_HEAD(&dreq->list);
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atomic_set(&dreq->count, 0);
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atomic_set(&dreq->error, 0);
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list = &dreq->list;
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for(;;) {
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struct nfs_read_data *data = nfs_readdata_alloc();
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if (unlikely(!data)) {
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while (!list_empty(list)) {
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data = list_entry(list->next,
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struct nfs_read_data, pages);
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list_del(&data->pages);
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nfs_readdata_free(data);
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}
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kref_put(&dreq->kref, nfs_direct_req_release);
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return NULL;
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}
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INIT_LIST_HEAD(&data->pages);
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list_add(&data->pages, list);
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data->req = (struct nfs_page *) dreq;
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reads++;
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if (nbytes <= rsize)
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break;
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nbytes -= rsize;
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}
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kref_get(&dreq->kref);
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atomic_set(&dreq->complete, reads);
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return dreq;
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}
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/**
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* nfs_direct_read_result - handle a read reply for a direct read request
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* @data: address of NFS READ operation control block
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* @status: status of this NFS READ operation
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*
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* We must hold a reference to all the pages in this direct read request
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* until the RPCs complete. This could be long *after* we are woken up in
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* nfs_direct_read_wait (for instance, if someone hits ^C on a slow server).
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*/
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static void nfs_direct_read_result(struct nfs_read_data *data, int status)
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{
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struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req;
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if (likely(status >= 0))
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atomic_add(data->res.count, &dreq->count);
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else
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atomic_set(&dreq->error, status);
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if (unlikely(atomic_dec_and_test(&dreq->complete))) {
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nfs_free_user_pages(dreq->pages, dreq->npages, 1);
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wake_up(&dreq->wait);
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kref_put(&dreq->kref, nfs_direct_req_release);
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}
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}
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/**
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* nfs_direct_read_schedule - dispatch NFS READ operations for a direct read
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* @dreq: address of nfs_direct_req struct for this request
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* @inode: target inode
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* @ctx: target file open context
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* @user_addr: starting address of this segment of user's buffer
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* @count: size of this segment
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* @file_offset: offset in file to begin the operation
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*
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* For each nfs_read_data struct that was allocated on the list, dispatch
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* an NFS READ operation
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*/
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static void nfs_direct_read_schedule(struct nfs_direct_req *dreq,
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struct inode *inode, struct nfs_open_context *ctx,
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unsigned long user_addr, size_t count, loff_t file_offset)
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{
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struct list_head *list = &dreq->list;
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struct page **pages = dreq->pages;
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unsigned int curpage, pgbase;
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unsigned int rsize = NFS_SERVER(inode)->rsize;
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curpage = 0;
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pgbase = user_addr & ~PAGE_MASK;
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do {
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struct nfs_read_data *data;
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unsigned int bytes;
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bytes = rsize;
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if (count < rsize)
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bytes = count;
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data = list_entry(list->next, struct nfs_read_data, pages);
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list_del_init(&data->pages);
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data->inode = inode;
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data->cred = ctx->cred;
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data->args.fh = NFS_FH(inode);
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data->args.context = ctx;
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data->args.offset = file_offset;
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data->args.pgbase = pgbase;
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data->args.pages = &pages[curpage];
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data->args.count = bytes;
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data->res.fattr = &data->fattr;
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data->res.eof = 0;
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data->res.count = bytes;
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NFS_PROTO(inode)->read_setup(data);
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data->task.tk_cookie = (unsigned long) inode;
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data->task.tk_calldata = data;
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data->task.tk_release = nfs_readdata_release;
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data->complete = nfs_direct_read_result;
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lock_kernel();
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rpc_execute(&data->task);
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unlock_kernel();
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dfprintk(VFS, "NFS: %4d initiated direct read call (req %s/%Ld, %u bytes @ offset %Lu)\n",
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data->task.tk_pid,
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inode->i_sb->s_id,
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(long long)NFS_FILEID(inode),
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bytes,
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(unsigned long long)data->args.offset);
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file_offset += bytes;
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pgbase += bytes;
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curpage += pgbase >> PAGE_SHIFT;
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pgbase &= ~PAGE_MASK;
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count -= bytes;
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} while (count != 0);
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}
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/**
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* nfs_direct_read_wait - wait for I/O completion for direct reads
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* @dreq: request on which we are to wait
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* @intr: whether or not this wait can be interrupted
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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_read_wait(struct nfs_direct_req *dreq, int intr)
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{
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int result = 0;
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if (intr) {
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result = wait_event_interruptible(dreq->wait,
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(atomic_read(&dreq->complete) == 0));
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} else {
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wait_event(dreq->wait, (atomic_read(&dreq->complete) == 0));
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}
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if (!result)
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result = atomic_read(&dreq->error);
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if (!result)
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result = atomic_read(&dreq->count);
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kref_put(&dreq->kref, nfs_direct_req_release);
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return (ssize_t) result;
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}
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/**
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* nfs_direct_read_seg - Read in one iov segment. Generate separate
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* read RPCs for each "rsize" bytes.
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* @inode: target inode
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* @ctx: target file open context
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* @user_addr: starting address of this segment of user's buffer
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* @count: size of this segment
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* @file_offset: offset in file to begin the operation
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* @pages: array of addresses of page structs defining user's buffer
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* @nr_pages: number of pages in the array
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*
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*/
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static ssize_t nfs_direct_read_seg(struct inode *inode,
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struct nfs_open_context *ctx, unsigned long user_addr,
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size_t count, loff_t file_offset, struct page **pages,
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unsigned int nr_pages)
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{
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ssize_t result;
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sigset_t oldset;
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struct rpc_clnt *clnt = NFS_CLIENT(inode);
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struct nfs_direct_req *dreq;
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dreq = nfs_direct_read_alloc(count, NFS_SERVER(inode)->rsize);
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if (!dreq)
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return -ENOMEM;
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dreq->pages = pages;
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dreq->npages = nr_pages;
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rpc_clnt_sigmask(clnt, &oldset);
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nfs_direct_read_schedule(dreq, inode, ctx, user_addr, count,
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file_offset);
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result = nfs_direct_read_wait(dreq, clnt->cl_intr);
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rpc_clnt_sigunmask(clnt, &oldset);
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return result;
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}
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/**
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* nfs_direct_read - For each iov segment, map the user's buffer
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* then generate read RPCs.
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* @inode: target inode
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* @ctx: target file open context
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* @iov: array of vectors that define I/O buffer
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* file_offset: 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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* We've already pushed out any non-direct writes so that this read
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* will see them when we read from the server.
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*/
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static ssize_t
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nfs_direct_read(struct inode *inode, struct nfs_open_context *ctx,
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const struct iovec *iov, loff_t file_offset,
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unsigned long nr_segs)
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{
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ssize_t tot_bytes = 0;
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unsigned long seg = 0;
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while ((seg < nr_segs) && (tot_bytes >= 0)) {
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ssize_t result;
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int page_count;
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struct page **pages;
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const struct iovec *vec = &iov[seg++];
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unsigned long user_addr = (unsigned long) vec->iov_base;
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size_t size = vec->iov_len;
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page_count = nfs_get_user_pages(READ, user_addr, size, &pages);
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if (page_count < 0) {
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nfs_free_user_pages(pages, 0, 0);
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if (tot_bytes > 0)
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break;
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return page_count;
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}
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result = nfs_direct_read_seg(inode, ctx, user_addr, size,
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file_offset, pages, page_count);
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if (result <= 0) {
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if (tot_bytes > 0)
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break;
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return result;
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}
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tot_bytes += result;
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file_offset += result;
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if (result < size)
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break;
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}
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return tot_bytes;
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}
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/**
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* nfs_direct_write_seg - Write out one iov segment. Generate separate
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* write RPCs for each "wsize" bytes, then commit.
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* @inode: target inode
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* @ctx: target file open context
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* user_addr: starting address of this segment of user's buffer
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* count: size of this segment
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* file_offset: offset in file to begin the operation
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* @pages: array of addresses of page structs defining user's buffer
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* nr_pages: size of pages array
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*/
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static ssize_t nfs_direct_write_seg(struct inode *inode,
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struct nfs_open_context *ctx, unsigned long user_addr,
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size_t count, loff_t file_offset, struct page **pages,
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int nr_pages)
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{
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const unsigned int wsize = NFS_SERVER(inode)->wsize;
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size_t request;
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int curpage, need_commit;
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ssize_t result, tot_bytes;
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struct nfs_writeverf first_verf;
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struct nfs_write_data *wdata;
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wdata = nfs_writedata_alloc();
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if (!wdata)
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return -ENOMEM;
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wdata->inode = inode;
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wdata->cred = ctx->cred;
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wdata->args.fh = NFS_FH(inode);
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wdata->args.context = ctx;
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wdata->args.stable = NFS_UNSTABLE;
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if (IS_SYNC(inode) || NFS_PROTO(inode)->version == 2 || count <= wsize)
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wdata->args.stable = NFS_FILE_SYNC;
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wdata->res.fattr = &wdata->fattr;
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wdata->res.verf = &wdata->verf;
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nfs_begin_data_update(inode);
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retry:
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need_commit = 0;
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tot_bytes = 0;
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curpage = 0;
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request = count;
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wdata->args.pgbase = user_addr & ~PAGE_MASK;
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wdata->args.offset = file_offset;
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do {
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wdata->args.count = request;
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if (wdata->args.count > wsize)
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wdata->args.count = wsize;
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wdata->args.pages = &pages[curpage];
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dprintk("NFS: direct write: c=%u o=%Ld ua=%lu, pb=%u, cp=%u\n",
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wdata->args.count, (long long) wdata->args.offset,
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user_addr + tot_bytes, wdata->args.pgbase, curpage);
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lock_kernel();
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result = NFS_PROTO(inode)->write(wdata);
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unlock_kernel();
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if (result <= 0) {
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if (tot_bytes > 0)
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break;
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goto out;
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}
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if (tot_bytes == 0)
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memcpy(&first_verf.verifier, &wdata->verf.verifier,
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sizeof(first_verf.verifier));
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if (wdata->verf.committed != NFS_FILE_SYNC) {
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need_commit = 1;
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if (memcmp(&first_verf.verifier, &wdata->verf.verifier,
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sizeof(first_verf.verifier)));
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goto sync_retry;
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}
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tot_bytes += result;
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/* in case of a short write: stop now, let the app recover */
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if (result < wdata->args.count)
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break;
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wdata->args.offset += result;
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wdata->args.pgbase += result;
|
|
curpage += wdata->args.pgbase >> PAGE_SHIFT;
|
|
wdata->args.pgbase &= ~PAGE_MASK;
|
|
request -= result;
|
|
} while (request != 0);
|
|
|
|
/*
|
|
* Commit data written so far, even in the event of an error
|
|
*/
|
|
if (need_commit) {
|
|
wdata->args.count = tot_bytes;
|
|
wdata->args.offset = file_offset;
|
|
|
|
lock_kernel();
|
|
result = NFS_PROTO(inode)->commit(wdata);
|
|
unlock_kernel();
|
|
|
|
if (result < 0 || memcmp(&first_verf.verifier,
|
|
&wdata->verf.verifier,
|
|
sizeof(first_verf.verifier)) != 0)
|
|
goto sync_retry;
|
|
}
|
|
result = tot_bytes;
|
|
|
|
out:
|
|
nfs_end_data_update_defer(inode);
|
|
nfs_writedata_free(wdata);
|
|
return result;
|
|
|
|
sync_retry:
|
|
wdata->args.stable = NFS_FILE_SYNC;
|
|
goto retry;
|
|
}
|
|
|
|
/**
|
|
* nfs_direct_write - For each iov segment, map the user's buffer
|
|
* then generate write and commit RPCs.
|
|
* @inode: target inode
|
|
* @ctx: target file open context
|
|
* @iov: array of vectors that define I/O buffer
|
|
* file_offset: offset in file to begin the operation
|
|
* nr_segs: size of iovec array
|
|
*
|
|
* Upon return, generic_file_direct_IO invalidates any cached pages
|
|
* that non-direct readers might access, so they will pick up these
|
|
* writes immediately.
|
|
*/
|
|
static ssize_t nfs_direct_write(struct inode *inode,
|
|
struct nfs_open_context *ctx, const struct iovec *iov,
|
|
loff_t file_offset, unsigned long nr_segs)
|
|
{
|
|
ssize_t tot_bytes = 0;
|
|
unsigned long seg = 0;
|
|
|
|
while ((seg < nr_segs) && (tot_bytes >= 0)) {
|
|
ssize_t result;
|
|
int page_count;
|
|
struct page **pages;
|
|
const struct iovec *vec = &iov[seg++];
|
|
unsigned long user_addr = (unsigned long) vec->iov_base;
|
|
size_t size = vec->iov_len;
|
|
|
|
page_count = nfs_get_user_pages(WRITE, user_addr, size, &pages);
|
|
if (page_count < 0) {
|
|
nfs_free_user_pages(pages, 0, 0);
|
|
if (tot_bytes > 0)
|
|
break;
|
|
return page_count;
|
|
}
|
|
|
|
result = nfs_direct_write_seg(inode, ctx, user_addr, size,
|
|
file_offset, pages, page_count);
|
|
nfs_free_user_pages(pages, page_count, 0);
|
|
|
|
if (result <= 0) {
|
|
if (tot_bytes > 0)
|
|
break;
|
|
return result;
|
|
}
|
|
tot_bytes += result;
|
|
file_offset += result;
|
|
if (result < size)
|
|
break;
|
|
}
|
|
return tot_bytes;
|
|
}
|
|
|
|
/**
|
|
* nfs_direct_IO - NFS address space operation for direct I/O
|
|
* rw: direction (read or write)
|
|
* @iocb: target I/O control block
|
|
* @iov: array of vectors that define I/O buffer
|
|
* file_offset: offset in file to begin the operation
|
|
* nr_segs: size of iovec array
|
|
*
|
|
*/
|
|
ssize_t
|
|
nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
|
|
loff_t file_offset, unsigned long nr_segs)
|
|
{
|
|
ssize_t result = -EINVAL;
|
|
struct file *file = iocb->ki_filp;
|
|
struct nfs_open_context *ctx;
|
|
struct dentry *dentry = file->f_dentry;
|
|
struct inode *inode = dentry->d_inode;
|
|
|
|
/*
|
|
* No support for async yet
|
|
*/
|
|
if (!is_sync_kiocb(iocb))
|
|
return result;
|
|
|
|
ctx = (struct nfs_open_context *)file->private_data;
|
|
switch (rw) {
|
|
case READ:
|
|
dprintk("NFS: direct_IO(read) (%s) off/no(%Lu/%lu)\n",
|
|
dentry->d_name.name, file_offset, nr_segs);
|
|
|
|
result = nfs_direct_read(inode, ctx, iov,
|
|
file_offset, nr_segs);
|
|
break;
|
|
case WRITE:
|
|
dprintk("NFS: direct_IO(write) (%s) off/no(%Lu/%lu)\n",
|
|
dentry->d_name.name, file_offset, nr_segs);
|
|
|
|
result = nfs_direct_write(inode, ctx, iov,
|
|
file_offset, nr_segs);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* nfs_file_direct_read - file direct read operation for NFS files
|
|
* @iocb: target I/O control block
|
|
* @buf: user's buffer into which to read data
|
|
* count: number of bytes to read
|
|
* pos: byte offset in file where reading starts
|
|
*
|
|
* We use this function for direct reads instead of calling
|
|
* generic_file_aio_read() in order to avoid gfar's check to see if
|
|
* the request starts before the end of the file. For that check
|
|
* to work, we must generate a GETATTR before each direct read, and
|
|
* even then there is a window between the GETATTR and the subsequent
|
|
* READ where the file size could change. So our preference is simply
|
|
* to do all reads the application wants, and the server will take
|
|
* care of managing the end of file boundary.
|
|
*
|
|
* This function also eliminates unnecessarily updating the file's
|
|
* atime locally, as the NFS server sets the file's atime, and this
|
|
* client must read the updated atime from the server back into its
|
|
* cache.
|
|
*/
|
|
ssize_t
|
|
nfs_file_direct_read(struct kiocb *iocb, char __user *buf, size_t count, loff_t pos)
|
|
{
|
|
ssize_t retval = -EINVAL;
|
|
loff_t *ppos = &iocb->ki_pos;
|
|
struct file *file = iocb->ki_filp;
|
|
struct nfs_open_context *ctx =
|
|
(struct nfs_open_context *) file->private_data;
|
|
struct dentry *dentry = file->f_dentry;
|
|
struct address_space *mapping = file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
struct iovec iov = {
|
|
.iov_base = buf,
|
|
.iov_len = count,
|
|
};
|
|
|
|
dprintk("nfs: direct read(%s/%s, %lu@%lu)\n",
|
|
dentry->d_parent->d_name.name, dentry->d_name.name,
|
|
(unsigned long) count, (unsigned long) pos);
|
|
|
|
if (!is_sync_kiocb(iocb))
|
|
goto out;
|
|
if (count < 0)
|
|
goto out;
|
|
retval = -EFAULT;
|
|
if (!access_ok(VERIFY_WRITE, iov.iov_base, iov.iov_len))
|
|
goto out;
|
|
retval = 0;
|
|
if (!count)
|
|
goto out;
|
|
|
|
if (mapping->nrpages) {
|
|
retval = filemap_fdatawrite(mapping);
|
|
if (retval == 0)
|
|
retval = nfs_wb_all(inode);
|
|
if (retval == 0)
|
|
retval = filemap_fdatawait(mapping);
|
|
if (retval)
|
|
goto out;
|
|
}
|
|
|
|
retval = nfs_direct_read(inode, ctx, &iov, pos, 1);
|
|
if (retval > 0)
|
|
*ppos = pos + retval;
|
|
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* nfs_file_direct_write - file direct write operation for NFS files
|
|
* @iocb: target I/O control block
|
|
* @buf: user's buffer from which to write data
|
|
* count: number of bytes to write
|
|
* pos: byte offset in file where writing starts
|
|
*
|
|
* We use this function for direct writes instead of calling
|
|
* generic_file_aio_write() in order to avoid taking the inode
|
|
* semaphore and updating the i_size. The NFS server will set
|
|
* the new i_size and this client must read the updated size
|
|
* back into its cache. We let the server do generic write
|
|
* parameter checking and report problems.
|
|
*
|
|
* We also avoid an unnecessary invocation of generic_osync_inode(),
|
|
* as it is fairly meaningless to sync the metadata of an NFS file.
|
|
*
|
|
* We eliminate local atime updates, see direct read above.
|
|
*
|
|
* We avoid unnecessary page cache invalidations for normal cached
|
|
* readers of this file.
|
|
*
|
|
* Note that O_APPEND is not supported for NFS direct writes, as there
|
|
* is no atomic O_APPEND write facility in the NFS protocol.
|
|
*/
|
|
ssize_t
|
|
nfs_file_direct_write(struct kiocb *iocb, const char __user *buf, size_t count, loff_t pos)
|
|
{
|
|
ssize_t retval = -EINVAL;
|
|
loff_t *ppos = &iocb->ki_pos;
|
|
unsigned long limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
|
|
struct file *file = iocb->ki_filp;
|
|
struct nfs_open_context *ctx =
|
|
(struct nfs_open_context *) file->private_data;
|
|
struct dentry *dentry = file->f_dentry;
|
|
struct address_space *mapping = file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
struct iovec iov = {
|
|
.iov_base = (char __user *)buf,
|
|
.iov_len = count,
|
|
};
|
|
|
|
dfprintk(VFS, "nfs: direct write(%s/%s(%ld), %lu@%lu)\n",
|
|
dentry->d_parent->d_name.name, dentry->d_name.name,
|
|
inode->i_ino, (unsigned long) count, (unsigned long) pos);
|
|
|
|
if (!is_sync_kiocb(iocb))
|
|
goto out;
|
|
if (count < 0)
|
|
goto out;
|
|
if (pos < 0)
|
|
goto out;
|
|
retval = -EFAULT;
|
|
if (!access_ok(VERIFY_READ, iov.iov_base, iov.iov_len))
|
|
goto out;
|
|
if (file->f_error) {
|
|
retval = file->f_error;
|
|
file->f_error = 0;
|
|
goto out;
|
|
}
|
|
retval = -EFBIG;
|
|
if (limit != RLIM_INFINITY) {
|
|
if (pos >= limit) {
|
|
send_sig(SIGXFSZ, current, 0);
|
|
goto out;
|
|
}
|
|
if (count > limit - (unsigned long) pos)
|
|
count = limit - (unsigned long) pos;
|
|
}
|
|
retval = 0;
|
|
if (!count)
|
|
goto out;
|
|
|
|
if (mapping->nrpages) {
|
|
retval = filemap_fdatawrite(mapping);
|
|
if (retval == 0)
|
|
retval = nfs_wb_all(inode);
|
|
if (retval == 0)
|
|
retval = filemap_fdatawait(mapping);
|
|
if (retval)
|
|
goto out;
|
|
}
|
|
|
|
retval = nfs_direct_write(inode, ctx, &iov, pos, 1);
|
|
if (mapping->nrpages)
|
|
invalidate_inode_pages2(mapping);
|
|
if (retval > 0)
|
|
*ppos = pos + retval;
|
|
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
int nfs_init_directcache(void)
|
|
{
|
|
nfs_direct_cachep = kmem_cache_create("nfs_direct_cache",
|
|
sizeof(struct nfs_direct_req),
|
|
0, SLAB_RECLAIM_ACCOUNT,
|
|
NULL, NULL);
|
|
if (nfs_direct_cachep == NULL)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void nfs_destroy_directcache(void)
|
|
{
|
|
if (kmem_cache_destroy(nfs_direct_cachep))
|
|
printk(KERN_INFO "nfs_direct_cache: not all structures were freed\n");
|
|
}
|