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write.c
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write.c
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/*
* linux/fs/nfs/write.c
*
* Write file data over NFS.
*
* Copyright (C) 1996, 1997, Olaf Kirch <[email protected]>
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/file.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs_page.h>
#include <linux/backing-dev.h>
#include <asm/uaccess.h>
#include <linux/smp_lock.h>
#include "delegation.h"
#include "internal.h"
#include "iostat.h"
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
#define MIN_POOL_WRITE (32)
#define MIN_POOL_COMMIT (4)
/*
* Local function declarations
*/
static struct nfs_page * nfs_update_request(struct nfs_open_context*,
struct page *,
unsigned int, unsigned int);
static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how);
static const struct rpc_call_ops nfs_write_partial_ops;
static const struct rpc_call_ops nfs_write_full_ops;
static const struct rpc_call_ops nfs_commit_ops;
static struct kmem_cache *nfs_wdata_cachep;
static mempool_t *nfs_wdata_mempool;
static mempool_t *nfs_commit_mempool;
struct nfs_write_data *nfs_commit_alloc(void)
{
struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
if (p) {
memset(p, 0, sizeof(*p));
INIT_LIST_HEAD(&p->pages);
}
return p;
}
void nfs_commit_rcu_free(struct rcu_head *head)
{
struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
if (p && (p->pagevec != &p->page_array[0]))
kfree(p->pagevec);
mempool_free(p, nfs_commit_mempool);
}
void nfs_commit_free(struct nfs_write_data *wdata)
{
call_rcu_bh(&wdata->task.u.tk_rcu, nfs_commit_rcu_free);
}
struct nfs_write_data *nfs_writedata_alloc(size_t len)
{
unsigned int pagecount = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
if (p) {
memset(p, 0, sizeof(*p));
INIT_LIST_HEAD(&p->pages);
p->npages = pagecount;
if (pagecount <= ARRAY_SIZE(p->page_array))
p->pagevec = p->page_array;
else {
p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
if (!p->pagevec) {
mempool_free(p, nfs_wdata_mempool);
p = NULL;
}
}
}
return p;
}
static void nfs_writedata_rcu_free(struct rcu_head *head)
{
struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
if (p && (p->pagevec != &p->page_array[0]))
kfree(p->pagevec);
mempool_free(p, nfs_wdata_mempool);
}
static void nfs_writedata_free(struct nfs_write_data *wdata)
{
call_rcu_bh(&wdata->task.u.tk_rcu, nfs_writedata_rcu_free);
}
void nfs_writedata_release(void *wdata)
{
nfs_writedata_free(wdata);
}
static struct nfs_page *nfs_page_find_request_locked(struct page *page)
{
struct nfs_page *req = NULL;
if (PagePrivate(page)) {
req = (struct nfs_page *)page_private(page);
if (req != NULL)
atomic_inc(&req->wb_count);
}
return req;
}
static struct nfs_page *nfs_page_find_request(struct page *page)
{
struct nfs_page *req = NULL;
spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;
spin_lock(req_lock);
req = nfs_page_find_request_locked(page);
spin_unlock(req_lock);
return req;
}
/* Adjust the file length if we're writing beyond the end */
static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
{
struct inode *inode = page->mapping->host;
loff_t end, i_size = i_size_read(inode);
unsigned long end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
if (i_size > 0 && page->index < end_index)
return;
end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
if (i_size >= end)
return;
nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
i_size_write(inode, end);
}
/* A writeback failed: mark the page as bad, and invalidate the page cache */
static void nfs_set_pageerror(struct page *page)
{
SetPageError(page);
nfs_zap_mapping(page->mapping->host, page->mapping);
}
/* We can set the PG_uptodate flag if we see that a write request
* covers the full page.
*/
static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
{
if (PageUptodate(page))
return;
if (base != 0)
return;
if (count != nfs_page_length(page))
return;
if (count != PAGE_CACHE_SIZE)
memclear_highpage_flush(page, count, PAGE_CACHE_SIZE - count);
SetPageUptodate(page);
}
static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
unsigned int offset, unsigned int count)
{
struct nfs_page *req;
int ret;
for (;;) {
req = nfs_update_request(ctx, page, offset, count);
if (!IS_ERR(req))
break;
ret = PTR_ERR(req);
if (ret != -EBUSY)
return ret;
ret = nfs_wb_page(page->mapping->host, page);
if (ret != 0)
return ret;
}
/* Update file length */
nfs_grow_file(page, offset, count);
/* Set the PG_uptodate flag? */
nfs_mark_uptodate(page, offset, count);
nfs_unlock_request(req);
return 0;
}
static int wb_priority(struct writeback_control *wbc)
{
if (wbc->for_reclaim)
return FLUSH_HIGHPRI;
if (wbc->for_kupdate)
return FLUSH_LOWPRI;
return 0;
}
/*
* NFS congestion control
*/
int nfs_congestion_kb;
#define NFS_CONGESTION_ON_THRESH (nfs_congestion_kb >> (PAGE_SHIFT-10))
#define NFS_CONGESTION_OFF_THRESH \
(NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
static int nfs_set_page_writeback(struct page *page)
{
int ret = test_set_page_writeback(page);
if (!ret) {
struct inode *inode = page->mapping->host;
struct nfs_server *nfss = NFS_SERVER(inode);
if (atomic_inc_return(&nfss->writeback) >
NFS_CONGESTION_ON_THRESH)
set_bdi_congested(&nfss->backing_dev_info, WRITE);
}
return ret;
}
static void nfs_end_page_writeback(struct page *page)
{
struct inode *inode = page->mapping->host;
struct nfs_server *nfss = NFS_SERVER(inode);
end_page_writeback(page);
if (atomic_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) {
clear_bdi_congested(&nfss->backing_dev_info, WRITE);
congestion_end(WRITE);
}
}
/*
* Find an associated nfs write request, and prepare to flush it out
* Returns 1 if there was no write request, or if the request was
* already tagged by nfs_set_page_dirty.Returns 0 if the request
* was not tagged.
* May also return an error if the user signalled nfs_wait_on_request().
*/
static int nfs_page_mark_flush(struct page *page)
{
struct nfs_page *req;
struct nfs_inode *nfsi = NFS_I(page->mapping->host);
spinlock_t *req_lock = &nfsi->req_lock;
int ret;
spin_lock(req_lock);
for(;;) {
req = nfs_page_find_request_locked(page);
if (req == NULL) {
spin_unlock(req_lock);
return 1;
}
if (nfs_lock_request_dontget(req))
break;
/* Note: If we hold the page lock, as is the case in nfs_writepage,
* then the call to nfs_lock_request_dontget() will always
* succeed provided that someone hasn't already marked the
* request as dirty (in which case we don't care).
*/
spin_unlock(req_lock);
ret = nfs_wait_on_request(req);
nfs_release_request(req);
if (ret != 0)
return ret;
spin_lock(req_lock);
}
if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
/* This request is marked for commit */
spin_unlock(req_lock);
nfs_unlock_request(req);
return 1;
}
if (nfs_set_page_writeback(page) == 0) {
nfs_list_remove_request(req);
/* add the request to the inode's dirty list. */
radix_tree_tag_set(&nfsi->nfs_page_tree,
req->wb_index, NFS_PAGE_TAG_DIRTY);
nfs_list_add_request(req, &nfsi->dirty);
nfsi->ndirty++;
spin_unlock(req_lock);
__mark_inode_dirty(page->mapping->host, I_DIRTY_PAGES);
} else
spin_unlock(req_lock);
ret = test_bit(PG_NEED_FLUSH, &req->wb_flags);
nfs_unlock_request(req);
return ret;
}
/*
* Write an mmapped page to the server.
*/
static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
{
struct nfs_open_context *ctx;
struct inode *inode = page->mapping->host;
unsigned offset;
int err;
nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
err = nfs_page_mark_flush(page);
if (err <= 0)
goto out;
err = 0;
offset = nfs_page_length(page);
if (!offset)
goto out;
ctx = nfs_find_open_context(inode, NULL, FMODE_WRITE);
if (ctx == NULL) {
err = -EBADF;
goto out;
}
err = nfs_writepage_setup(ctx, page, 0, offset);
put_nfs_open_context(ctx);
if (err != 0)
goto out;
err = nfs_page_mark_flush(page);
if (err > 0)
err = 0;
out:
if (!wbc->for_writepages)
nfs_flush_mapping(page->mapping, wbc, FLUSH_STABLE|wb_priority(wbc));
return err;
}
int nfs_writepage(struct page *page, struct writeback_control *wbc)
{
int err;
err = nfs_writepage_locked(page, wbc);
unlock_page(page);
return err;
}
int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
struct inode *inode = mapping->host;
int err;
nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
err = generic_writepages(mapping, wbc);
if (err)
return err;
err = nfs_flush_mapping(mapping, wbc, wb_priority(wbc));
if (err < 0)
goto out;
nfs_add_stats(inode, NFSIOS_WRITEPAGES, err);
err = 0;
out:
return err;
}
/*
* Insert a write request into an inode
*/
static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
{
struct nfs_inode *nfsi = NFS_I(inode);
int error;
error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
BUG_ON(error == -EEXIST);
if (error)
return error;
if (!nfsi->npages) {
igrab(inode);
nfs_begin_data_update(inode);
if (nfs_have_delegation(inode, FMODE_WRITE))
nfsi->change_attr++;
}
SetPagePrivate(req->wb_page);
set_page_private(req->wb_page, (unsigned long)req);
if (PageDirty(req->wb_page))
set_bit(PG_NEED_FLUSH, &req->wb_flags);
nfsi->npages++;
atomic_inc(&req->wb_count);
return 0;
}
/*
* Remove a write request from an inode
*/
static void nfs_inode_remove_request(struct nfs_page *req)
{
struct inode *inode = req->wb_context->dentry->d_inode;
struct nfs_inode *nfsi = NFS_I(inode);
BUG_ON (!NFS_WBACK_BUSY(req));
spin_lock(&nfsi->req_lock);
set_page_private(req->wb_page, 0);
ClearPagePrivate(req->wb_page);
radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
if (test_and_clear_bit(PG_NEED_FLUSH, &req->wb_flags))
__set_page_dirty_nobuffers(req->wb_page);
nfsi->npages--;
if (!nfsi->npages) {
spin_unlock(&nfsi->req_lock);
nfs_end_data_update(inode);
iput(inode);
} else
spin_unlock(&nfsi->req_lock);
nfs_clear_request(req);
nfs_release_request(req);
}
static void
nfs_redirty_request(struct nfs_page *req)
{
__set_page_dirty_nobuffers(req->wb_page);
}
/*
* Check if a request is dirty
*/
static inline int
nfs_dirty_request(struct nfs_page *req)
{
struct page *page = req->wb_page;
if (page == NULL || test_bit(PG_NEED_COMMIT, &req->wb_flags))
return 0;
return !PageWriteback(req->wb_page);
}
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
/*
* Add a request to the inode's commit list.
*/
static void
nfs_mark_request_commit(struct nfs_page *req)
{
struct inode *inode = req->wb_context->dentry->d_inode;
struct nfs_inode *nfsi = NFS_I(inode);
spin_lock(&nfsi->req_lock);
nfs_list_add_request(req, &nfsi->commit);
nfsi->ncommit++;
set_bit(PG_NEED_COMMIT, &(req)->wb_flags);
spin_unlock(&nfsi->req_lock);
inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
}
static inline
int nfs_write_need_commit(struct nfs_write_data *data)
{
return data->verf.committed != NFS_FILE_SYNC;
}
static inline
int nfs_reschedule_unstable_write(struct nfs_page *req)
{
if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
nfs_mark_request_commit(req);
return 1;
}
if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
nfs_redirty_request(req);
return 1;
}
return 0;
}
#else
static inline void
nfs_mark_request_commit(struct nfs_page *req)
{
}
static inline
int nfs_write_need_commit(struct nfs_write_data *data)
{
return 0;
}
static inline
int nfs_reschedule_unstable_write(struct nfs_page *req)
{
return 0;
}
#endif
/*
* Wait for a request to complete.
*
* Interruptible by signals only if mounted with intr flag.
*/
static int nfs_wait_on_requests_locked(struct inode *inode, unsigned long idx_start, unsigned int npages)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_page *req;
unsigned long idx_end, next;
unsigned int res = 0;
int error;
if (npages == 0)
idx_end = ~0;
else
idx_end = idx_start + npages - 1;
next = idx_start;
while (radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, (void **)&req, next, 1, NFS_PAGE_TAG_WRITEBACK)) {
if (req->wb_index > idx_end)
break;
next = req->wb_index + 1;
BUG_ON(!NFS_WBACK_BUSY(req));
atomic_inc(&req->wb_count);
spin_unlock(&nfsi->req_lock);
error = nfs_wait_on_request(req);
nfs_release_request(req);
spin_lock(&nfsi->req_lock);
if (error < 0)
return error;
res++;
}
return res;
}
static void nfs_cancel_dirty_list(struct list_head *head)
{
struct nfs_page *req;
while(!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_end_page_writeback(req->wb_page);
nfs_inode_remove_request(req);
nfs_clear_page_writeback(req);
}
}
static void nfs_cancel_commit_list(struct list_head *head)
{
struct nfs_page *req;
while(!list_empty(head)) {
req = nfs_list_entry(head->next);
dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
nfs_list_remove_request(req);
clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
nfs_inode_remove_request(req);
nfs_unlock_request(req);
}
}
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
/*
* nfs_scan_commit - Scan an inode for commit requests
* @inode: NFS inode to scan
* @dst: destination list
* @idx_start: lower bound of page->index to scan.
* @npages: idx_start + npages sets the upper bound to scan.
*
* Moves requests from the inode's 'commit' request list.
* The requests are *not* checked to ensure that they form a contiguous set.
*/
static int
nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
{
struct nfs_inode *nfsi = NFS_I(inode);
int res = 0;
if (nfsi->ncommit != 0) {
res = nfs_scan_list(nfsi, &nfsi->commit, dst, idx_start, npages);
nfsi->ncommit -= res;
if ((nfsi->ncommit == 0) != list_empty(&nfsi->commit))
printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n");
}
return res;
}
#else
static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
{
return 0;
}
#endif
static int nfs_wait_on_write_congestion(struct address_space *mapping)
{
struct inode *inode = mapping->host;
struct backing_dev_info *bdi = mapping->backing_dev_info;
int ret = 0;
might_sleep();
if (!bdi_write_congested(bdi))
return 0;
nfs_inc_stats(inode, NFSIOS_CONGESTIONWAIT);
do {
struct rpc_clnt *clnt = NFS_CLIENT(inode);
sigset_t oldset;
rpc_clnt_sigmask(clnt, &oldset);
ret = congestion_wait_interruptible(WRITE, HZ/10);
rpc_clnt_sigunmask(clnt, &oldset);
if (ret == -ERESTARTSYS)
break;
ret = 0;
} while (bdi_write_congested(bdi));
return ret;
}
/*
* Try to update any existing write request, or create one if there is none.
* In order to match, the request's credentials must match those of
* the calling process.
*
* Note: Should always be called with the Page Lock held!
*/
static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
struct page *page, unsigned int offset, unsigned int bytes)
{
struct address_space *mapping = page->mapping;
struct inode *inode = mapping->host;
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_page *req, *new = NULL;
unsigned long rqend, end;
end = offset + bytes;
if (nfs_wait_on_write_congestion(mapping))
return ERR_PTR(-ERESTARTSYS);
for (;;) {
/* Loop over all inode entries and see if we find
* A request for the page we wish to update
*/
spin_lock(&nfsi->req_lock);
req = nfs_page_find_request_locked(page);
if (req) {
if (!nfs_lock_request_dontget(req)) {
int error;
spin_unlock(&nfsi->req_lock);
error = nfs_wait_on_request(req);
nfs_release_request(req);
if (error < 0) {
if (new)
nfs_release_request(new);
return ERR_PTR(error);
}
continue;
}
spin_unlock(&nfsi->req_lock);
if (new)
nfs_release_request(new);
break;
}
if (new) {
int error;
nfs_lock_request_dontget(new);
error = nfs_inode_add_request(inode, new);
if (error) {
spin_unlock(&nfsi->req_lock);
nfs_unlock_request(new);
return ERR_PTR(error);
}
spin_unlock(&nfsi->req_lock);
return new;
}
spin_unlock(&nfsi->req_lock);
new = nfs_create_request(ctx, inode, page, offset, bytes);
if (IS_ERR(new))
return new;
}
/* We have a request for our page.
* If the creds don't match, or the
* page addresses don't match,
* tell the caller to wait on the conflicting
* request.
*/
rqend = req->wb_offset + req->wb_bytes;
if (req->wb_context != ctx
|| req->wb_page != page
|| !nfs_dirty_request(req)
|| offset > rqend || end < req->wb_offset) {
nfs_unlock_request(req);
return ERR_PTR(-EBUSY);
}
/* Okay, the request matches. Update the region */
if (offset < req->wb_offset) {
req->wb_offset = offset;
req->wb_pgbase = offset;
req->wb_bytes = rqend - req->wb_offset;
}
if (end > rqend)
req->wb_bytes = end - req->wb_offset;
return req;
}
int nfs_flush_incompatible(struct file *file, struct page *page)
{
struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
struct nfs_page *req;
int do_flush, status;
/*
* Look for a request corresponding to this page. If there
* is one, and it belongs to another file, we flush it out
* before we try to copy anything into the page. Do this
* due to the lack of an ACCESS-type call in NFSv2.
* Also do the same if we find a request from an existing
* dropped page.
*/
do {
req = nfs_page_find_request(page);
if (req == NULL)
return 0;
do_flush = req->wb_page != page || req->wb_context != ctx
|| !nfs_dirty_request(req);
nfs_release_request(req);
if (!do_flush)
return 0;
status = nfs_wb_page(page->mapping->host, page);
} while (status == 0);
return status;
}
/*
* Update and possibly write a cached page of an NFS file.
*
* XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
* things with a page scheduled for an RPC call (e.g. invalidate it).
*/
int nfs_updatepage(struct file *file, struct page *page,
unsigned int offset, unsigned int count)
{
struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
struct inode *inode = page->mapping->host;
int status = 0;
nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
dprintk("NFS: nfs_updatepage(%s/%s %d@%Ld)\n",
file->f_path.dentry->d_parent->d_name.name,
file->f_path.dentry->d_name.name, count,
(long long)(page_offset(page) +offset));
/* If we're not using byte range locks, and we know the page
* is entirely in cache, it may be more efficient to avoid
* fragmenting write requests.
*/
if (PageUptodate(page) && inode->i_flock == NULL && !(file->f_mode & O_SYNC)) {
count = max(count + offset, nfs_page_length(page));
offset = 0;
}
status = nfs_writepage_setup(ctx, page, offset, count);
__set_page_dirty_nobuffers(page);
dprintk("NFS: nfs_updatepage returns %d (isize %Ld)\n",
status, (long long)i_size_read(inode));
if (status < 0)
nfs_set_pageerror(page);
return status;
}
static void nfs_writepage_release(struct nfs_page *req)
{
if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req)) {
nfs_end_page_writeback(req->wb_page);
nfs_inode_remove_request(req);
} else
nfs_end_page_writeback(req->wb_page);
nfs_clear_page_writeback(req);
}
static inline int flush_task_priority(int how)
{
switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
case FLUSH_HIGHPRI:
return RPC_PRIORITY_HIGH;
case FLUSH_LOWPRI:
return RPC_PRIORITY_LOW;
}
return RPC_PRIORITY_NORMAL;
}
/*
* Set up the argument/result storage required for the RPC call.
*/
static void nfs_write_rpcsetup(struct nfs_page *req,
struct nfs_write_data *data,
const struct rpc_call_ops *call_ops,
unsigned int count, unsigned int offset,
int how)
{
struct inode *inode;
int flags;
/* Set up the RPC argument and reply structs
* NB: take care not to mess about with data->commit et al. */
data->req = req;
data->inode = inode = req->wb_context->dentry->d_inode;
data->cred = req->wb_context->cred;
data->args.fh = NFS_FH(inode);
data->args.offset = req_offset(req) + offset;
data->args.pgbase = req->wb_pgbase + offset;
data->args.pages = data->pagevec;
data->args.count = count;
data->args.context = req->wb_context;
data->res.fattr = &data->fattr;
data->res.count = count;
data->res.verf = &data->verf;
nfs_fattr_init(&data->fattr);
/* Set up the initial task struct. */
flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
rpc_init_task(&data->task, NFS_CLIENT(inode), flags, call_ops, data);
NFS_PROTO(inode)->write_setup(data, how);
data->task.tk_priority = flush_task_priority(how);
data->task.tk_cookie = (unsigned long)inode;
dprintk("NFS: %5u initiated write call "
"(req %s/%Ld, %u bytes @ offset %Lu)\n",
data->task.tk_pid,
inode->i_sb->s_id,
(long long)NFS_FILEID(inode),
count,
(unsigned long long)data->args.offset);
}
static void nfs_execute_write(struct nfs_write_data *data)
{
struct rpc_clnt *clnt = NFS_CLIENT(data->inode);
sigset_t oldset;
rpc_clnt_sigmask(clnt, &oldset);
rpc_execute(&data->task);
rpc_clnt_sigunmask(clnt, &oldset);
}
/*
* Generate multiple small requests to write out a single
* contiguous dirty area on one page.
*/
static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
{
struct nfs_page *req = nfs_list_entry(head->next);
struct page *page = req->wb_page;
struct nfs_write_data *data;
size_t wsize = NFS_SERVER(inode)->wsize, nbytes;
unsigned int offset;
int requests = 0;
LIST_HEAD(list);
nfs_list_remove_request(req);
nbytes = req->wb_bytes;
do {
size_t len = min(nbytes, wsize);
data = nfs_writedata_alloc(len);
if (!data)
goto out_bad;
list_add(&data->pages, &list);
requests++;
nbytes -= len;
} while (nbytes != 0);
atomic_set(&req->wb_complete, requests);
ClearPageError(page);
offset = 0;
nbytes = req->wb_bytes;
do {
data = list_entry(list.next, struct nfs_write_data, pages);
list_del_init(&data->pages);
data->pagevec[0] = page;
if (nbytes > wsize) {
nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
wsize, offset, how);
offset += wsize;
nbytes -= wsize;
} else {
nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
nbytes, offset, how);
nbytes = 0;
}
nfs_execute_write(data);
} while (nbytes != 0);
return 0;
out_bad:
while (!list_empty(&list)) {
data = list_entry(list.next, struct nfs_write_data, pages);
list_del(&data->pages);
nfs_writedata_release(data);
}
nfs_redirty_request(req);
nfs_end_page_writeback(req->wb_page);
nfs_clear_page_writeback(req);
return -ENOMEM;
}
/*
* Create an RPC task for the given write request and kick it.
* The page must have been locked by the caller.
*
* It may happen that the page we're passed is not marked dirty.
* This is the case if nfs_updatepage detects a conflicting request
* that has been written but not committed.
*/
static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
{
struct nfs_page *req;
struct page **pages;
struct nfs_write_data *data;
unsigned int count;
data = nfs_writedata_alloc(NFS_SERVER(inode)->wsize);
if (!data)
goto out_bad;
pages = data->pagevec;
count = 0;
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_list_add_request(req, &data->pages);
ClearPageError(req->wb_page);
*pages++ = req->wb_page;
count += req->wb_bytes;
}
req = nfs_list_entry(data->pages.next);
/* Set up the argument struct */
nfs_write_rpcsetup(req, data, &nfs_write_full_ops, count, 0, how);
nfs_execute_write(data);
return 0;
out_bad:
while (!list_empty(head)) {
struct nfs_page *req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_redirty_request(req);
nfs_end_page_writeback(req->wb_page);
nfs_clear_page_writeback(req);
}
return -ENOMEM;
}
static int nfs_flush_list(struct inode *inode, struct list_head *head, int npages, int how)
{
LIST_HEAD(one_request);
int (*flush_one)(struct inode *, struct list_head *, int);
struct nfs_page *req;
int wpages = NFS_SERVER(inode)->wpages;
int wsize = NFS_SERVER(inode)->wsize;
int error;
flush_one = nfs_flush_one;
if (wsize < PAGE_CACHE_SIZE)
flush_one = nfs_flush_multi;
/* For single writes, FLUSH_STABLE is more efficient */
if (npages <= wpages && npages == NFS_I(inode)->npages
&& nfs_list_entry(head->next)->wb_bytes <= wsize)
how |= FLUSH_STABLE;
do {
nfs_coalesce_requests(head, &one_request, wpages);
req = nfs_list_entry(one_request.next);
error = flush_one(inode, &one_request, how);
if (error < 0)
goto out_err;
} while (!list_empty(head));
return 0;