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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/nfs/write.c

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44 KiB
C
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/*
* linux/fs/nfs/write.c
*
* Write file data over NFS.
*
* Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
*/
#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/migrate.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 <linux/export.h>
#include <asm/uaccess.h>
#include "delegation.h"
#include "internal.h"
#include "iostat.h"
#include "nfs4_fs.h"
#include "fscache.h"
#include "pnfs.h"
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
#define MIN_POOL_WRITE (32)
#define MIN_POOL_COMMIT (4)
/*
* Local function declarations
*/
static void nfs_pageio_init_write(struct nfs_pageio_descriptor *desc,
struct inode *inode, int ioflags);
static void nfs_redirty_request(struct nfs_page *req);
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_commitdata_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;
}
EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
void nfs_commit_free(struct nfs_write_data *p)
{
if (p && (p->pagevec != &p->page_array[0]))
kfree(p->pagevec);
mempool_free(p, nfs_commit_mempool);
}
EXPORT_SYMBOL_GPL(nfs_commit_free);
struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
{
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;
}
void nfs_writedata_free(struct nfs_write_data *p)
{
if (p && (p->pagevec != &p->page_array[0]))
kfree(p->pagevec);
mempool_free(p, nfs_wdata_mempool);
}
void nfs_writedata_release(struct nfs_write_data *wdata)
{
put_lseg(wdata->lseg);
put_nfs_open_context(wdata->args.context);
nfs_writedata_free(wdata);
}
static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
{
ctx->error = error;
smp_wmb();
set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
}
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)
kref_get(&req->wb_kref);
}
return req;
}
static struct nfs_page *nfs_page_find_request(struct page *page)
{
struct inode *inode = page->mapping->host;
struct nfs_page *req = NULL;
spin_lock(&inode->i_lock);
req = nfs_page_find_request_locked(page);
spin_unlock(&inode->i_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;
pgoff_t end_index;
spin_lock(&inode->i_lock);
i_size = i_size_read(inode);
end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
if (i_size > 0 && page->index < end_index)
goto out;
end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
if (i_size >= end)
goto out;
i_size_write(inode, end);
nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
out:
spin_unlock(&inode->i_lock);
}
/* 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;
SetPageUptodate(page);
}
static int wb_priority(struct writeback_control *wbc)
{
if (wbc->for_reclaim)
return FLUSH_HIGHPRI | FLUSH_STABLE;
if (wbc->for_kupdate || wbc->for_background)
return FLUSH_LOWPRI | FLUSH_COND_STABLE;
return FLUSH_COND_STABLE;
}
/*
* 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);
page_cache_get(page);
if (atomic_long_inc_return(&nfss->writeback) >
NFS_CONGESTION_ON_THRESH) {
set_bdi_congested(&nfss->backing_dev_info,
BLK_RW_ASYNC);
}
}
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);
page_cache_release(page);
if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
}
static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
{
struct inode *inode = page->mapping->host;
struct nfs_page *req;
int ret;
spin_lock(&inode->i_lock);
for (;;) {
req = nfs_page_find_request_locked(page);
if (req == NULL)
break;
if (nfs_set_page_tag_locked(req))
break;
/* Note: If we hold the page lock, as is the case in nfs_writepage,
* then the call to nfs_set_page_tag_locked() will always
* succeed provided that someone hasn't already marked the
* request as dirty (in which case we don't care).
*/
spin_unlock(&inode->i_lock);
if (!nonblock)
ret = nfs_wait_on_request(req);
else
ret = -EAGAIN;
nfs_release_request(req);
if (ret != 0)
return ERR_PTR(ret);
spin_lock(&inode->i_lock);
}
spin_unlock(&inode->i_lock);
return req;
}
/*
* Find an associated nfs write request, and prepare to flush it out
* May return an error if the user signalled nfs_wait_on_request().
*/
static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
struct page *page, bool nonblock)
{
struct nfs_page *req;
int ret = 0;
req = nfs_find_and_lock_request(page, nonblock);
if (!req)
goto out;
ret = PTR_ERR(req);
if (IS_ERR(req))
goto out;
ret = nfs_set_page_writeback(page);
BUG_ON(ret != 0);
BUG_ON(test_bit(PG_CLEAN, &req->wb_flags));
if (!nfs_pageio_add_request(pgio, req)) {
nfs_redirty_request(req);
ret = pgio->pg_error;
}
out:
return ret;
}
static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
{
struct inode *inode = page->mapping->host;
int ret;
nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
nfs_pageio_cond_complete(pgio, page->index);
ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
if (ret == -EAGAIN) {
redirty_page_for_writepage(wbc, page);
ret = 0;
}
return ret;
}
/*
* Write an mmapped page to the server.
*/
static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
{
struct nfs_pageio_descriptor pgio;
int err;
nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc));
err = nfs_do_writepage(page, wbc, &pgio);
nfs_pageio_complete(&pgio);
if (err < 0)
return err;
if (pgio.pg_error < 0)
return pgio.pg_error;
return 0;
}
int nfs_writepage(struct page *page, struct writeback_control *wbc)
{
int ret;
ret = nfs_writepage_locked(page, wbc);
unlock_page(page);
return ret;
}
static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
{
int ret;
ret = nfs_do_writepage(page, wbc, data);
unlock_page(page);
return ret;
}
int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
struct inode *inode = mapping->host;
unsigned long *bitlock = &NFS_I(inode)->flags;
struct nfs_pageio_descriptor pgio;
int err;
/* Stop dirtying of new pages while we sync */
err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
nfs_wait_bit_killable, TASK_KILLABLE);
if (err)
goto out_err;
nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
nfs_pageio_init_write(&pgio, inode, wb_priority(wbc));
err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
nfs_pageio_complete(&pgio);
clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
smp_mb__after_clear_bit();
wake_up_bit(bitlock, NFS_INO_FLUSHING);
if (err < 0)
goto out_err;
err = pgio.pg_error;
if (err < 0)
goto out_err;
return 0;
out_err:
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_preload(GFP_NOFS);
if (error != 0)
goto out;
/* Lock the request! */
nfs_lock_request_dontget(req);
spin_lock(&inode->i_lock);
error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
BUG_ON(error);
if (!nfsi->npages && nfs_have_delegation(inode, FMODE_WRITE))
inode->i_version++;
set_bit(PG_MAPPED, &req->wb_flags);
SetPagePrivate(req->wb_page);
set_page_private(req->wb_page, (unsigned long)req);
nfsi->npages++;
kref_get(&req->wb_kref);
radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
NFS_PAGE_TAG_LOCKED);
spin_unlock(&inode->i_lock);
radix_tree_preload_end();
out:
return error;
}
/*
* 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(&inode->i_lock);
set_page_private(req->wb_page, 0);
ClearPagePrivate(req->wb_page);
clear_bit(PG_MAPPED, &req->wb_flags);
radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
nfsi->npages--;
spin_unlock(&inode->i_lock);
nfs_release_request(req);
}
static void
nfs_mark_request_dirty(struct nfs_page *req)
{
__set_page_dirty_nobuffers(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 pnfs_layout_segment *lseg)
{
struct inode *inode = req->wb_context->dentry->d_inode;
struct nfs_inode *nfsi = NFS_I(inode);
spin_lock(&inode->i_lock);
set_bit(PG_CLEAN, &(req)->wb_flags);
radix_tree_tag_set(&nfsi->nfs_page_tree,
req->wb_index,
NFS_PAGE_TAG_COMMIT);
nfsi->ncommit++;
spin_unlock(&inode->i_lock);
pnfs_mark_request_commit(req, lseg);
inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
}
static int
nfs_clear_request_commit(struct nfs_page *req)
{
struct page *page = req->wb_page;
if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
dec_zone_page_state(page, NR_UNSTABLE_NFS);
dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
return 1;
}
return 0;
}
static inline
int nfs_write_need_commit(struct nfs_write_data *data)
{
if (data->verf.committed == NFS_DATA_SYNC)
return data->lseg == NULL;
else
return data->verf.committed != NFS_FILE_SYNC;
}
static inline
int nfs_reschedule_unstable_write(struct nfs_page *req,
struct nfs_write_data *data)
{
if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {
nfs_mark_request_commit(req, data->lseg);
return 1;
}
if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
nfs_mark_request_dirty(req);
return 1;
}
return 0;
}
#else
static inline void
nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
{
}
static inline int
nfs_clear_request_commit(struct nfs_page *req)
{
return 0;
}
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,
struct nfs_write_data *data)
{
return 0;
}
#endif
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
static int
nfs_need_commit(struct nfs_inode *nfsi)
{
return radix_tree_tagged(&nfsi->nfs_page_tree, NFS_PAGE_TAG_COMMIT);
}
/*
* 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, pgoff_t idx_start, unsigned int npages)
{
struct nfs_inode *nfsi = NFS_I(inode);
int ret;
if (!nfs_need_commit(nfsi))
return 0;
spin_lock(&inode->i_lock);
ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
if (ret > 0)
nfsi->ncommit -= ret;
spin_unlock(&inode->i_lock);
if (nfs_need_commit(NFS_I(inode)))
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
return ret;
}
#else
static inline int nfs_need_commit(struct nfs_inode *nfsi)
{
return 0;
}
static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
{
return 0;
}
#endif
/*
* Search for an existing write request, and attempt to update
* it to reflect a new dirty region on a given page.
*
* If the attempt fails, then the existing request is flushed out
* to disk.
*/
static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
struct page *page,
unsigned int offset,
unsigned int bytes)
{
struct nfs_page *req;
unsigned int rqend;
unsigned int end;
int error;
if (!PagePrivate(page))
return NULL;
end = offset + bytes;
spin_lock(&inode->i_lock);
for (;;) {
req = nfs_page_find_request_locked(page);
if (req == NULL)
goto out_unlock;
rqend = req->wb_offset + req->wb_bytes;
/*
* Tell the caller to flush out the request if
* the offsets are non-contiguous.
* Note: nfs_flush_incompatible() will already
* have flushed out requests having wrong owners.
*/
if (offset > rqend
|| end < req->wb_offset)
goto out_flushme;
if (nfs_set_page_tag_locked(req))
break;
/* The request is locked, so wait and then retry */
spin_unlock(&inode->i_lock);
error = nfs_wait_on_request(req);
nfs_release_request(req);
if (error != 0)
goto out_err;
spin_lock(&inode->i_lock);
}
if (nfs_clear_request_commit(req) &&
radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
req->wb_index, NFS_PAGE_TAG_COMMIT) != NULL) {
NFS_I(inode)->ncommit--;
pnfs_clear_request_commit(req);
}
/* Okay, the request matches. Update the region */
if (offset < req->wb_offset) {
req->wb_offset = offset;
req->wb_pgbase = offset;
}
if (end > rqend)
req->wb_bytes = end - req->wb_offset;
else
req->wb_bytes = rqend - req->wb_offset;
out_unlock:
spin_unlock(&inode->i_lock);
return req;
out_flushme:
spin_unlock(&inode->i_lock);
nfs_release_request(req);
error = nfs_wb_page(inode, page);
out_err:
return ERR_PTR(error);
}
/*
* Try to update an existing write request, or create one if there is none.
*
* Note: Should always be called with the Page Lock held to prevent races
* if we have to add a new request. Also assumes that the caller has
* already called nfs_flush_incompatible() if necessary.
*/
static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
struct page *page, unsigned int offset, unsigned int bytes)
{
struct inode *inode = page->mapping->host;
struct nfs_page *req;
int error;
req = nfs_try_to_update_request(inode, page, offset, bytes);
if (req != NULL)
goto out;
req = nfs_create_request(ctx, inode, page, offset, bytes);
if (IS_ERR(req))
goto out;
error = nfs_inode_add_request(inode, req);
if (error != 0) {
nfs_release_request(req);
req = ERR_PTR(error);
}
out:
return req;
}
static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
unsigned int offset, unsigned int count)
{
struct nfs_page *req;
req = nfs_setup_write_request(ctx, page, offset, count);
if (IS_ERR(req))
return PTR_ERR(req);
/* Update file length */
nfs_grow_file(page, offset, count);
nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
nfs_mark_request_dirty(req);
nfs_clear_page_tag_locked(req);
return 0;
}
int nfs_flush_incompatible(struct file *file, struct page *page)
{
struct nfs_open_context *ctx = nfs_file_open_context(file);
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 ||
req->wb_lock_context->lockowner != current->files ||
req->wb_lock_context->pid != current->tgid;
nfs_release_request(req);
if (!do_flush)
return 0;
status = nfs_wb_page(page->mapping->host, page);
} while (status == 0);
return status;
}
/*
* If the page cache is marked as unsafe or invalid, then we can't rely on
* the PageUptodate() flag. In this case, we will need to turn off
* write optimisations that depend on the page contents being correct.
*/
static int nfs_write_pageuptodate(struct page *page, struct inode *inode)
{
return PageUptodate(page) &&
!(NFS_I(inode)->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA));
}
/*
* 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 = nfs_file_open_context(file);
struct inode *inode = page->mapping->host;
int status = 0;
nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
dprintk("NFS: nfs_updatepage(%s/%s %d@%lld)\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 up to date, it may be more efficient to extend the write
* to cover the entire page in order to avoid fragmentation
* inefficiencies.
*/
if (nfs_write_pageuptodate(page, inode) &&
inode->i_flock == NULL &&
!(file->f_flags & O_DSYNC)) {
count = max(count + offset, nfs_page_length(page));
offset = 0;
}
status = nfs_writepage_setup(ctx, page, offset, count);
if (status < 0)
nfs_set_pageerror(page);
else
__set_page_dirty_nobuffers(page);
dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n",
status, (long long)i_size_read(inode));
return status;
}
static void nfs_writepage_release(struct nfs_page *req,
struct nfs_write_data *data)
{
struct page *page = req->wb_page;
if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req, data))
nfs_inode_remove_request(req);
nfs_clear_page_tag_locked(req);
nfs_end_page_writeback(page);
}
static 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;
}
int nfs_initiate_write(struct nfs_write_data *data,
struct rpc_clnt *clnt,
const struct rpc_call_ops *call_ops,
int how)
{
struct inode *inode = data->inode;
int priority = flush_task_priority(how);
struct rpc_task *task;
struct rpc_message msg = {
.rpc_argp = &data->args,
.rpc_resp = &data->res,
.rpc_cred = data->cred,
};
struct rpc_task_setup task_setup_data = {
.rpc_client = clnt,
.task = &data->task,
.rpc_message = &msg,
.callback_ops = call_ops,
.callback_data = data,
.workqueue = nfsiod_workqueue,
.flags = RPC_TASK_ASYNC,
.priority = priority,
};
int ret = 0;
/* Set up the initial task struct. */
NFS_PROTO(inode)->write_setup(data, &msg);
dprintk("NFS: %5u initiated write call "
"(req %s/%lld, %u bytes @ offset %llu)\n",
data->task.tk_pid,
inode->i_sb->s_id,
(long long)NFS_FILEID(inode),
data->args.count,
(unsigned long long)data->args.offset);
task = rpc_run_task(&task_setup_data);
if (IS_ERR(task)) {
ret = PTR_ERR(task);
goto out;
}
if (how & FLUSH_SYNC) {
ret = rpc_wait_for_completion_task(task);
if (ret == 0)
ret = task->tk_status;
}
rpc_put_task(task);
out:
return ret;
}
EXPORT_SYMBOL_GPL(nfs_initiate_write);
/*
* 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,
unsigned int count, unsigned int offset,
int how)
{
struct inode *inode = req->wb_context->dentry->d_inode;
/* 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;
/* pnfs_set_layoutcommit needs this */
data->mds_offset = data->args.offset;
data->args.pgbase = req->wb_pgbase + offset;
data->args.pages = data->pagevec;
data->args.count = count;
data->args.context = get_nfs_open_context(req->wb_context);
data->args.lock_context = req->wb_lock_context;
data->args.stable = NFS_UNSTABLE;
switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
case 0:
break;
case FLUSH_COND_STABLE:
if (nfs_need_commit(NFS_I(inode)))
break;
default:
data->args.stable = NFS_FILE_SYNC;
}
data->res.fattr = &data->fattr;
data->res.count = count;
data->res.verf = &data->verf;
nfs_fattr_init(&data->fattr);
}
static int nfs_do_write(struct nfs_write_data *data,
const struct rpc_call_ops *call_ops,
int how)
{
struct inode *inode = data->args.context->dentry->d_inode;
return nfs_initiate_write(data, NFS_CLIENT(inode), call_ops, how);
}
static int nfs_do_multiple_writes(struct list_head *head,
const struct rpc_call_ops *call_ops,
int how)
{
struct nfs_write_data *data;
int ret = 0;
while (!list_empty(head)) {
int ret2;
data = list_entry(head->next, struct nfs_write_data, list);
list_del_init(&data->list);
ret2 = nfs_do_write(data, call_ops, how);
if (ret == 0)
ret = ret2;
}
return ret;
}
/* If a nfs_flush_* function fails, it should remove reqs from @head and
* call this on each, which will prepare them to be retried on next
* writeback using standard nfs.
*/
static void nfs_redirty_request(struct nfs_page *req)
{
struct page *page = req->wb_page;
nfs_mark_request_dirty(req);
nfs_clear_page_tag_locked(req);
nfs_end_page_writeback(page);
}
/*
* Generate multiple small requests to write out a single
* contiguous dirty area on one page.
*/
static int nfs_flush_multi(struct nfs_pageio_descriptor *desc, struct list_head *res)
{
struct nfs_page *req = nfs_list_entry(desc->pg_list.next);
struct page *page = req->wb_page;
struct nfs_write_data *data;
size_t wsize = desc->pg_bsize, nbytes;
unsigned int offset;
int requests = 0;
int ret = 0;
nfs_list_remove_request(req);
if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
(desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit ||
desc->pg_count > wsize))
desc->pg_ioflags &= ~FLUSH_COND_STABLE;
offset = 0;
nbytes = desc->pg_count;
do {
size_t len = min(nbytes, wsize);
data = nfs_writedata_alloc(1);
if (!data)
goto out_bad;
data->pagevec[0] = page;
nfs_write_rpcsetup(req, data, len, offset, desc->pg_ioflags);
list_add(&data->list, res);
requests++;
nbytes -= len;
offset += len;
} while (nbytes != 0);
atomic_set(&req->wb_complete, requests);
desc->pg_rpc_callops = &nfs_write_partial_ops;
return ret;
out_bad:
while (!list_empty(res)) {
data = list_entry(res->next, struct nfs_write_data, list);
list_del(&data->list);
nfs_writedata_free(data);
}
nfs_redirty_request(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 nfs_pageio_descriptor *desc, struct list_head *res)
{
struct nfs_page *req;
struct page **pages;
struct nfs_write_data *data;
struct list_head *head = &desc->pg_list;
int ret = 0;
data = nfs_writedata_alloc(nfs_page_array_len(desc->pg_base,
desc->pg_count));
if (!data) {
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_redirty_request(req);
}
ret = -ENOMEM;
goto out;
}
pages = data->pagevec;
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
nfs_list_add_request(req, &data->pages);
*pages++ = req->wb_page;
}
req = nfs_list_entry(data->pages.next);
if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
(desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit))
desc->pg_ioflags &= ~FLUSH_COND_STABLE;
/* Set up the argument struct */
nfs_write_rpcsetup(req, data, desc->pg_count, 0, desc->pg_ioflags);
list_add(&data->list, res);
desc->pg_rpc_callops = &nfs_write_full_ops;
out:
return ret;
}
int nfs_generic_flush(struct nfs_pageio_descriptor *desc, struct list_head *head)
{
if (desc->pg_bsize < PAGE_CACHE_SIZE)
return nfs_flush_multi(desc, head);
return nfs_flush_one(desc, head);
}
static int nfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
{
LIST_HEAD(head);
int ret;
ret = nfs_generic_flush(desc, &head);
if (ret == 0)
ret = nfs_do_multiple_writes(&head, desc->pg_rpc_callops,
desc->pg_ioflags);
return ret;
}
static const struct nfs_pageio_ops nfs_pageio_write_ops = {
.pg_test = nfs_generic_pg_test,
.pg_doio = nfs_generic_pg_writepages,
};
void nfs_pageio_init_write_mds(struct nfs_pageio_descriptor *pgio,
struct inode *inode, int ioflags)
{
nfs_pageio_init(pgio, inode, &nfs_pageio_write_ops,
NFS_SERVER(inode)->wsize, ioflags);
}
void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
{
pgio->pg_ops = &nfs_pageio_write_ops;
pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
}
EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
struct inode *inode, int ioflags)
{
if (!pnfs_pageio_init_write(pgio, inode, ioflags))
nfs_pageio_init_write_mds(pgio, inode, ioflags);
}
/*
* Handle a write reply that flushed part of a page.
*/
static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
{
struct nfs_write_data *data = calldata;
dprintk("NFS: %5u write(%s/%lld %d@%lld)",
task->tk_pid,
data->req->wb_context->dentry->d_inode->i_sb->s_id,
(long long)
NFS_FILEID(data->req->wb_context->dentry->d_inode),
data->req->wb_bytes, (long long)req_offset(data->req));
nfs_writeback_done(task, data);
}
static void nfs_writeback_release_partial(void *calldata)
{
struct nfs_write_data *data = calldata;
struct nfs_page *req = data->req;
struct page *page = req->wb_page;
int status = data->task.tk_status;
if (status < 0) {
nfs_set_pageerror(page);
nfs_context_set_write_error(req->wb_context, status);
dprintk(", error = %d\n", status);
goto out;
}
if (nfs_write_need_commit(data)) {
struct inode *inode = page->mapping->host;
spin_lock(&inode->i_lock);
if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
/* Do nothing we need to resend the writes */
} else if (!test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) {
memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
dprintk(" defer commit\n");
} else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
set_bit(PG_NEED_RESCHED, &req->wb_flags);
clear_bit(PG_NEED_COMMIT, &req->wb_flags);
dprintk(" server reboot detected\n");
}
spin_unlock(&inode->i_lock);
} else
dprintk(" OK\n");
out:
if (atomic_dec_and_test(&req->wb_complete))
nfs_writepage_release(req, data);
nfs_writedata_release(calldata);
}
#if defined(CONFIG_NFS_V4_1)
void nfs_write_prepare(struct rpc_task *task, void *calldata)
{
struct nfs_write_data *data = calldata;
if (nfs4_setup_sequence(NFS_SERVER(data->inode),
&data->args.seq_args,
&data->res.seq_res, task))
return;
rpc_call_start(task);
}
#endif /* CONFIG_NFS_V4_1 */
static const struct rpc_call_ops nfs_write_partial_ops = {
#if defined(CONFIG_NFS_V4_1)
.rpc_call_prepare = nfs_write_prepare,
#endif /* CONFIG_NFS_V4_1 */
.rpc_call_done = nfs_writeback_done_partial,
.rpc_release = nfs_writeback_release_partial,
};
/*
* Handle a write reply that flushes a whole page.
*
* FIXME: There is an inherent race with invalidate_inode_pages and
* writebacks since the page->count is kept > 1 for as long
* as the page has a write request pending.
*/
static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
{
struct nfs_write_data *data = calldata;
nfs_writeback_done(task, data);
}
static void nfs_writeback_release_full(void *calldata)
{
struct nfs_write_data *data = calldata;
int status = data->task.tk_status;
/* Update attributes as result of writeback. */
while (!list_empty(&data->pages)) {
struct nfs_page *req = nfs_list_entry(data->pages.next);
struct page *page = req->wb_page;
nfs_list_remove_request(req);
dprintk("NFS: %5u write (%s/%lld %d@%lld)",
data->task.tk_pid,
req->wb_context->dentry->d_inode->i_sb->s_id,
(long long)NFS_FILEID(req->wb_context->dentry->d_inode),
req->wb_bytes,
(long long)req_offset(req));
if (status < 0) {
nfs_set_pageerror(page);
nfs_context_set_write_error(req->wb_context, status);
dprintk(", error = %d\n", status);
goto remove_request;
}
if (nfs_write_need_commit(data)) {
memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
nfs_mark_request_commit(req, data->lseg);
dprintk(" marked for commit\n");
goto next;
}
dprintk(" OK\n");
remove_request:
nfs_inode_remove_request(req);
next:
nfs_clear_page_tag_locked(req);
nfs_end_page_writeback(page);
}
nfs_writedata_release(calldata);
}
static const struct rpc_call_ops nfs_write_full_ops = {
#if defined(CONFIG_NFS_V4_1)
.rpc_call_prepare = nfs_write_prepare,
#endif /* CONFIG_NFS_V4_1 */
.rpc_call_done = nfs_writeback_done_full,
.rpc_release = nfs_writeback_release_full,
};
/*
* This function is called when the WRITE call is complete.
*/
void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
{
struct nfs_writeargs *argp = &data->args;
struct nfs_writeres *resp = &data->res;
int status;
dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
task->tk_pid, task->tk_status);
/*
* ->write_done will attempt to use post-op attributes to detect
* conflicting writes by other clients. A strict interpretation
* of close-to-open would allow us to continue caching even if
* another writer had changed the file, but some applications
* depend on tighter cache coherency when writing.
*/
status = NFS_PROTO(data->inode)->write_done(task, data);
if (status != 0)
return;
nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
/* We tried a write call, but the server did not
* commit data to stable storage even though we
* requested it.
* Note: There is a known bug in Tru64 < 5.0 in which
* the server reports NFS_DATA_SYNC, but performs
* NFS_FILE_SYNC. We therefore implement this checking
* as a dprintk() in order to avoid filling syslog.
*/
static unsigned long complain;
/* Note this will print the MDS for a DS write */
if (time_before(complain, jiffies)) {
dprintk("NFS: faulty NFS server %s:"
" (committed = %d) != (stable = %d)\n",
NFS_SERVER(data->inode)->nfs_client->cl_hostname,
resp->verf->committed, argp->stable);
complain = jiffies + 300 * HZ;
}
}
#endif
/* Is this a short write? */
if (task->tk_status >= 0 && resp->count < argp->count) {
static unsigned long complain;
nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
/* Has the server at least made some progress? */
if (resp->count != 0) {
/* Was this an NFSv2 write or an NFSv3 stable write? */
if (resp->verf->committed != NFS_UNSTABLE) {
/* Resend from where the server left off */
data->mds_offset += resp->count;
argp->offset += resp->count;
argp->pgbase += resp->count;
argp->count -= resp->count;
} else {
/* Resend as a stable write in order to avoid
* headaches in the case of a server crash.
*/
argp->stable = NFS_FILE_SYNC;
}
rpc_restart_call_prepare(task);
return;
}
if (time_before(complain, jiffies)) {
printk(KERN_WARNING
"NFS: Server wrote zero bytes, expected %u.\n",
argp->count);
complain = jiffies + 300 * HZ;
}
/* Can't do anything about it except throw an error. */
task->tk_status = -EIO;
}
return;
}
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
{
int ret;
if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
return 1;
if (!may_wait)
return 0;
ret = out_of_line_wait_on_bit_lock(&nfsi->flags,
NFS_INO_COMMIT,
nfs_wait_bit_killable,
TASK_KILLABLE);
return (ret < 0) ? ret : 1;
}
void nfs_commit_clear_lock(struct nfs_inode *nfsi)
{
clear_bit(NFS_INO_COMMIT, &nfsi->flags);
smp_mb__after_clear_bit();
wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
}
EXPORT_SYMBOL_GPL(nfs_commit_clear_lock);
void nfs_commitdata_release(void *data)
{
struct nfs_write_data *wdata = data;
put_lseg(wdata->lseg);
put_nfs_open_context(wdata->args.context);
nfs_commit_free(wdata);
}
EXPORT_SYMBOL_GPL(nfs_commitdata_release);
int nfs_initiate_commit(struct nfs_write_data *data, struct rpc_clnt *clnt,
const struct rpc_call_ops *call_ops,
int how)
{
struct rpc_task *task;
int priority = flush_task_priority(how);
struct rpc_message msg = {
.rpc_argp = &data->args,
.rpc_resp = &data->res,
.rpc_cred = data->cred,
};
struct rpc_task_setup task_setup_data = {
.task = &data->task,
.rpc_client = clnt,
.rpc_message = &msg,
.callback_ops = call_ops,
.callback_data = data,
.workqueue = nfsiod_workqueue,
.flags = RPC_TASK_ASYNC,
.priority = priority,
};
/* Set up the initial task struct. */
NFS_PROTO(data->inode)->commit_setup(data, &msg);
dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
task = rpc_run_task(&task_setup_data);
if (IS_ERR(task))
return PTR_ERR(task);
if (how & FLUSH_SYNC)
rpc_wait_for_completion_task(task);
rpc_put_task(task);
return 0;
}
EXPORT_SYMBOL_GPL(nfs_initiate_commit);
/*
* Set up the argument/result storage required for the RPC call.
*/
void nfs_init_commit(struct nfs_write_data *data,
struct list_head *head,
struct pnfs_layout_segment *lseg)
{
struct nfs_page *first = nfs_list_entry(head->next);
struct inode *inode = first->wb_context->dentry->d_inode;
/* Set up the RPC argument and reply structs
* NB: take care not to mess about with data->commit et al. */
list_splice_init(head, &data->pages);
data->inode = inode;
data->cred = first->wb_context->cred;
data->lseg = lseg; /* reference transferred */
data->mds_ops = &nfs_commit_ops;
data->args.fh = NFS_FH(data->inode);
/* Note: we always request a commit of the entire inode */
data->args.offset = 0;
data->args.count = 0;
data->args.context = get_nfs_open_context(first->wb_context);
data->res.count = 0;
data->res.fattr = &data->fattr;
data->res.verf = &data->verf;
nfs_fattr_init(&data->fattr);
}
EXPORT_SYMBOL_GPL(nfs_init_commit);
void nfs_retry_commit(struct list_head *page_list,
struct pnfs_layout_segment *lseg)
{
struct nfs_page *req;
while (!list_empty(page_list)) {
req = nfs_list_entry(page_list->next);
nfs_list_remove_request(req);
nfs_mark_request_commit(req, lseg);
dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
BDI_RECLAIMABLE);
nfs_clear_page_tag_locked(req);
}
}
EXPORT_SYMBOL_GPL(nfs_retry_commit);
/*
* Commit dirty pages
*/
static int
nfs_commit_list(struct inode *inode, struct list_head *head, int how)
{
struct nfs_write_data *data;
data = nfs_commitdata_alloc();
if (!data)
goto out_bad;
/* Set up the argument struct */
nfs_init_commit(data, head, NULL);
return nfs_initiate_commit(data, NFS_CLIENT(inode), data->mds_ops, how);
out_bad:
nfs_retry_commit(head, NULL);
nfs_commit_clear_lock(NFS_I(inode));
return -ENOMEM;
}
/*
* COMMIT call returned
*/
static void nfs_commit_done(struct rpc_task *task, void *calldata)
{
struct nfs_write_data *data = calldata;
dprintk("NFS: %5u nfs_commit_done (status %d)\n",
task->tk_pid, task->tk_status);
/* Call the NFS version-specific code */
NFS_PROTO(data->inode)->commit_done(task, data);
}
void nfs_commit_release_pages(struct nfs_write_data *data)
{
struct nfs_page *req;
int status = data->task.tk_status;
while (!list_empty(&data->pages)) {
req = nfs_list_entry(data->pages.next);
nfs_list_remove_request(req);
nfs_clear_request_commit(req);
dprintk("NFS: commit (%s/%lld %d@%lld)",
req->wb_context->dentry->d_sb->s_id,
(long long)NFS_FILEID(req->wb_context->dentry->d_inode),
req->wb_bytes,
(long long)req_offset(req));
if (status < 0) {
nfs_context_set_write_error(req->wb_context, status);
nfs_inode_remove_request(req);
dprintk(", error = %d\n", status);
goto next;
}
/* Okay, COMMIT succeeded, apparently. Check the verifier
* returned by the server against all stored verfs. */
if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
/* We have a match */
nfs_inode_remove_request(req);
dprintk(" OK\n");
goto next;
}
/* We have a mismatch. Write the page again */
dprintk(" mismatch\n");
nfs_mark_request_dirty(req);
next:
nfs_clear_page_tag_locked(req);
}
}
EXPORT_SYMBOL_GPL(nfs_commit_release_pages);
static void nfs_commit_release(void *calldata)
{
struct nfs_write_data *data = calldata;
nfs_commit_release_pages(data);
nfs_commit_clear_lock(NFS_I(data->inode));
nfs_commitdata_release(calldata);
}
static const struct rpc_call_ops nfs_commit_ops = {
#if defined(CONFIG_NFS_V4_1)
.rpc_call_prepare = nfs_write_prepare,
#endif /* CONFIG_NFS_V4_1 */
.rpc_call_done = nfs_commit_done,
.rpc_release = nfs_commit_release,
};
int nfs_commit_inode(struct inode *inode, int how)
{
LIST_HEAD(head);
int may_wait = how & FLUSH_SYNC;
int res;
res = nfs_commit_set_lock(NFS_I(inode), may_wait);
if (res <= 0)
goto out_mark_dirty;
res = nfs_scan_commit(inode, &head, 0, 0);
if (res) {
int error;
error = pnfs_commit_list(inode, &head, how);
if (error == PNFS_NOT_ATTEMPTED)
error = nfs_commit_list(inode, &head, how);
if (error < 0)
return error;
if (!may_wait)
goto out_mark_dirty;
error = wait_on_bit(&NFS_I(inode)->flags,
NFS_INO_COMMIT,
nfs_wait_bit_killable,
TASK_KILLABLE);
if (error < 0)
return error;
} else
nfs_commit_clear_lock(NFS_I(inode));
return res;
/* Note: If we exit without ensuring that the commit is complete,
* we must mark the inode as dirty. Otherwise, future calls to
* sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
* that the data is on the disk.
*/
out_mark_dirty:
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
return res;
}
static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
{
struct nfs_inode *nfsi = NFS_I(inode);
int flags = FLUSH_SYNC;
int ret = 0;
/* no commits means nothing needs to be done */
if (!nfsi->ncommit)
return ret;
if (wbc->sync_mode == WB_SYNC_NONE) {
/* Don't commit yet if this is a non-blocking flush and there
* are a lot of outstanding writes for this mapping.
*/
if (nfsi->ncommit <= (nfsi->npages >> 1))
goto out_mark_dirty;
/* don't wait for the COMMIT response */
flags = 0;
}
ret = nfs_commit_inode(inode, flags);
if (ret >= 0) {
if (wbc->sync_mode == WB_SYNC_NONE) {
if (ret < wbc->nr_to_write)
wbc->nr_to_write -= ret;
else
wbc->nr_to_write = 0;
}
return 0;
}
out_mark_dirty:
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
return ret;
}
#else
static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
{
return 0;
}
#endif
int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
{
int ret;
ret = nfs_commit_unstable_pages(inode, wbc);
if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
int status;
bool sync = true;
if (wbc->sync_mode == WB_SYNC_NONE)
sync = false;
status = pnfs_layoutcommit_inode(inode, sync);
if (status < 0)
return status;
}
return ret;
}
/*
* flush the inode to disk.
*/
int nfs_wb_all(struct inode *inode)
{
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
.nr_to_write = LONG_MAX,
.range_start = 0,
.range_end = LLONG_MAX,
};
return sync_inode(inode, &wbc);
}
int nfs_wb_page_cancel(struct inode *inode, struct page *page)
{
struct nfs_page *req;
int ret = 0;
BUG_ON(!PageLocked(page));
for (;;) {
wait_on_page_writeback(page);
req = nfs_page_find_request(page);
if (req == NULL)
break;
if (nfs_lock_request_dontget(req)) {
nfs_inode_remove_request(req);
/*
* In case nfs_inode_remove_request has marked the
* page as being dirty
*/
cancel_dirty_page(page, PAGE_CACHE_SIZE);
nfs_unlock_request(req);
break;
}
ret = nfs_wait_on_request(req);
nfs_release_request(req);
if (ret < 0)
break;
}
return ret;
}
/*
* Write back all requests on one page - we do this before reading it.
*/
int nfs_wb_page(struct inode *inode, struct page *page)
{
loff_t range_start = page_offset(page);
loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
.nr_to_write = 0,
.range_start = range_start,
.range_end = range_end,
};
int ret;
for (;;) {
wait_on_page_writeback(page);
if (clear_page_dirty_for_io(page)) {
ret = nfs_writepage_locked(page, &wbc);
if (ret < 0)
goto out_error;
continue;
}
if (!PagePrivate(page))
break;
ret = nfs_commit_inode(inode, FLUSH_SYNC);
if (ret < 0)
goto out_error;
}
return 0;
out_error:
return ret;
}
#ifdef CONFIG_MIGRATION
int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
struct page *page, enum migrate_mode mode)
{
/*
* If PagePrivate is set, then the page is currently associated with
* an in-progress read or write request. Don't try to migrate it.
*
* FIXME: we could do this in principle, but we'll need a way to ensure
* that we can safely release the inode reference while holding
* the page lock.
*/
if (PagePrivate(page))
return -EBUSY;
nfs_fscache_release_page(page, GFP_KERNEL);
return migrate_page(mapping, newpage, page, mode);
}
#endif
int __init nfs_init_writepagecache(void)
{
nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
sizeof(struct nfs_write_data),
0, SLAB_HWCACHE_ALIGN,
NULL);
if (nfs_wdata_cachep == NULL)
return -ENOMEM;
nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
nfs_wdata_cachep);
if (nfs_wdata_mempool == NULL)
return -ENOMEM;
nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
nfs_wdata_cachep);
if (nfs_commit_mempool == NULL)
return -ENOMEM;
/*
* NFS congestion size, scale with available memory.
*
* 64MB: 8192k
* 128MB: 11585k
* 256MB: 16384k
* 512MB: 23170k
* 1GB: 32768k
* 2GB: 46340k
* 4GB: 65536k
* 8GB: 92681k
* 16GB: 131072k
*
* This allows larger machines to have larger/more transfers.
* Limit the default to 256M
*/
nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
if (nfs_congestion_kb > 256*1024)
nfs_congestion_kb = 256*1024;
return 0;
}
void nfs_destroy_writepagecache(void)
{
mempool_destroy(nfs_commit_mempool);
mempool_destroy(nfs_wdata_mempool);
kmem_cache_destroy(nfs_wdata_cachep);
}
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