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linuxdebug/fs/nfs/write.c

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null pointer error
2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0-only
/*
* 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 <linux/freezer.h>
#include <linux/wait.h>
#include <linux/iversion.h>
#include <linux/uaccess.h>
#include <linux/sched/mm.h>
#include "delegation.h"
#include "internal.h"
#include "iostat.h"
#include "nfs4_fs.h"
#include "fscache.h"
#include "pnfs.h"
#include "nfstrace.h"
#define NFSDBG_FACILITY NFSDBG_PAGECACHE
#define MIN_POOL_WRITE (32)
#define MIN_POOL_COMMIT (4)
struct nfs_io_completion {
void (*complete)(void *data);
void *data;
struct kref refcount;
};
/*
* Local function declarations
*/
static void nfs_redirty_request(struct nfs_page *req);
static const struct rpc_call_ops nfs_commit_ops;
static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
static const struct nfs_rw_ops nfs_rw_write_ops;
static void nfs_inode_remove_request(struct nfs_page *req);
static void nfs_clear_request_commit(struct nfs_page *req);
static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
struct inode *inode);
static struct nfs_page *
nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
struct page *page);
static struct kmem_cache *nfs_wdata_cachep;
static mempool_t *nfs_wdata_mempool;
static struct kmem_cache *nfs_cdata_cachep;
static mempool_t *nfs_commit_mempool;
struct nfs_commit_data *nfs_commitdata_alloc(void)
{
struct nfs_commit_data *p;
p = kmem_cache_zalloc(nfs_cdata_cachep, nfs_io_gfp_mask());
if (!p) {
p = mempool_alloc(nfs_commit_mempool, GFP_NOWAIT);
if (!p)
return NULL;
memset(p, 0, sizeof(*p));
}
INIT_LIST_HEAD(&p->pages);
return p;
}
EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
void nfs_commit_free(struct nfs_commit_data *p)
{
mempool_free(p, nfs_commit_mempool);
}
EXPORT_SYMBOL_GPL(nfs_commit_free);
static struct nfs_pgio_header *nfs_writehdr_alloc(void)
{
struct nfs_pgio_header *p;
p = kmem_cache_zalloc(nfs_wdata_cachep, nfs_io_gfp_mask());
if (!p) {
p = mempool_alloc(nfs_wdata_mempool, GFP_NOWAIT);
if (!p)
return NULL;
memset(p, 0, sizeof(*p));
}
p->rw_mode = FMODE_WRITE;
return p;
}
static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
{
mempool_free(hdr, nfs_wdata_mempool);
}
static struct nfs_io_completion *nfs_io_completion_alloc(gfp_t gfp_flags)
{
return kmalloc(sizeof(struct nfs_io_completion), gfp_flags);
}
static void nfs_io_completion_init(struct nfs_io_completion *ioc,
void (*complete)(void *), void *data)
{
ioc->complete = complete;
ioc->data = data;
kref_init(&ioc->refcount);
}
static void nfs_io_completion_release(struct kref *kref)
{
struct nfs_io_completion *ioc = container_of(kref,
struct nfs_io_completion, refcount);
ioc->complete(ioc->data);
kfree(ioc);
}
static void nfs_io_completion_get(struct nfs_io_completion *ioc)
{
if (ioc != NULL)
kref_get(&ioc->refcount);
}
static void nfs_io_completion_put(struct nfs_io_completion *ioc)
{
if (ioc != NULL)
kref_put(&ioc->refcount, nfs_io_completion_release);
}
static void
nfs_page_set_inode_ref(struct nfs_page *req, struct inode *inode)
{
if (!test_and_set_bit(PG_INODE_REF, &req->wb_flags)) {
kref_get(&req->wb_kref);
atomic_long_inc(&NFS_I(inode)->nrequests);
}
}
static int
nfs_cancel_remove_inode(struct nfs_page *req, struct inode *inode)
{
int ret;
if (!test_bit(PG_REMOVE, &req->wb_flags))
return 0;
ret = nfs_page_group_lock(req);
if (ret)
return ret;
if (test_and_clear_bit(PG_REMOVE, &req->wb_flags))
nfs_page_set_inode_ref(req, inode);
nfs_page_group_unlock(req);
return 0;
}
static struct nfs_page *
nfs_page_private_request(struct page *page)
{
if (!PagePrivate(page))
return NULL;
return (struct nfs_page *)page_private(page);
}
/*
* nfs_page_find_head_request_locked - find head request associated with @page
*
* must be called while holding the inode lock.
*
* returns matching head request with reference held, or NULL if not found.
*/
static struct nfs_page *
nfs_page_find_private_request(struct page *page)
{
struct address_space *mapping = page_file_mapping(page);
struct nfs_page *req;
if (!PagePrivate(page))
return NULL;
spin_lock(&mapping->private_lock);
req = nfs_page_private_request(page);
if (req) {
WARN_ON_ONCE(req->wb_head != req);
kref_get(&req->wb_kref);
}
spin_unlock(&mapping->private_lock);
return req;
}
static struct nfs_page *
nfs_page_find_swap_request(struct page *page)
{
struct inode *inode = page_file_mapping(page)->host;
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_page *req = NULL;
if (!PageSwapCache(page))
return NULL;
mutex_lock(&nfsi->commit_mutex);
if (PageSwapCache(page)) {
req = nfs_page_search_commits_for_head_request_locked(nfsi,
page);
if (req) {
WARN_ON_ONCE(req->wb_head != req);
kref_get(&req->wb_kref);
}
}
mutex_unlock(&nfsi->commit_mutex);
return req;
}
/*
* nfs_page_find_head_request - find head request associated with @page
*
* returns matching head request with reference held, or NULL if not found.
*/
static struct nfs_page *nfs_page_find_head_request(struct page *page)
{
struct nfs_page *req;
req = nfs_page_find_private_request(page);
if (!req)
req = nfs_page_find_swap_request(page);
return req;
}
static struct nfs_page *nfs_find_and_lock_page_request(struct page *page)
{
struct inode *inode = page_file_mapping(page)->host;
struct nfs_page *req, *head;
int ret;
for (;;) {
req = nfs_page_find_head_request(page);
if (!req)
return req;
head = nfs_page_group_lock_head(req);
if (head != req)
nfs_release_request(req);
if (IS_ERR(head))
return head;
ret = nfs_cancel_remove_inode(head, inode);
if (ret < 0) {
nfs_unlock_and_release_request(head);
return ERR_PTR(ret);
}
/* Ensure that nobody removed the request before we locked it */
if (head == nfs_page_private_request(page))
break;
if (PageSwapCache(page))
break;
nfs_unlock_and_release_request(head);
}
return head;
}
/* 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_file_mapping(page)->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_SHIFT;
if (i_size > 0 && page_index(page) < end_index)
goto out;
end = page_file_offset(page) + ((loff_t)offset+count);
if (i_size >= end)
goto out;
trace_nfs_size_grow(inode, end);
i_size_write(inode, end);
NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;
nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
out:
spin_unlock(&inode->i_lock);
nfs_fscache_invalidate(inode, 0);
}
/* A writeback failed: mark the page as bad, and invalidate the page cache */
static void nfs_set_pageerror(struct address_space *mapping)
{
struct inode *inode = mapping->host;
nfs_zap_mapping(mapping->host, mapping);
/* Force file size revalidation */
spin_lock(&inode->i_lock);
nfs_set_cache_invalid(inode, NFS_INO_REVAL_FORCED |
NFS_INO_INVALID_CHANGE |
NFS_INO_INVALID_SIZE);
spin_unlock(&inode->i_lock);
}
static void nfs_mapping_set_error(struct page *page, int error)
{
struct address_space *mapping = page_file_mapping(page);
SetPageError(page);
filemap_set_wb_err(mapping, error);
if (mapping->host)
errseq_set(&mapping->host->i_sb->s_wb_err,
error == -ENOSPC ? -ENOSPC : -EIO);
nfs_set_pageerror(mapping);
}
/*
* nfs_page_group_search_locked
* @head - head request of page group
* @page_offset - offset into page
*
* Search page group with head @head to find a request that contains the
* page offset @page_offset.
*
* Returns a pointer to the first matching nfs request, or NULL if no
* match is found.
*
* Must be called with the page group lock held
*/
static struct nfs_page *
nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)
{
struct nfs_page *req;
req = head;
do {
if (page_offset >= req->wb_pgbase &&
page_offset < (req->wb_pgbase + req->wb_bytes))
return req;
req = req->wb_this_page;
} while (req != head);
return NULL;
}
/*
* nfs_page_group_covers_page
* @head - head request of page group
*
* Return true if the page group with head @head covers the whole page,
* returns false otherwise
*/
static bool nfs_page_group_covers_page(struct nfs_page *req)
{
struct nfs_page *tmp;
unsigned int pos = 0;
unsigned int len = nfs_page_length(req->wb_page);
nfs_page_group_lock(req);
for (;;) {
tmp = nfs_page_group_search_locked(req->wb_head, pos);
if (!tmp)
break;
pos = tmp->wb_pgbase + tmp->wb_bytes;
}
nfs_page_group_unlock(req);
return pos >= len;
}
/* We can set the PG_uptodate flag if we see that a write request
* covers the full page.
*/
static void nfs_mark_uptodate(struct nfs_page *req)
{
if (PageUptodate(req->wb_page))
return;
if (!nfs_page_group_covers_page(req))
return;
SetPageUptodate(req->wb_page);
}
static int wb_priority(struct writeback_control *wbc)
{
int ret = 0;
if (wbc->sync_mode == WB_SYNC_ALL)
ret = FLUSH_COND_STABLE;
return ret;
}
/*
* 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 void nfs_set_page_writeback(struct page *page)
{
struct inode *inode = page_file_mapping(page)->host;
struct nfs_server *nfss = NFS_SERVER(inode);
int ret = test_set_page_writeback(page);
WARN_ON_ONCE(ret != 0);
if (atomic_long_inc_return(&nfss->writeback) >
NFS_CONGESTION_ON_THRESH)
nfss->write_congested = 1;
}
static void nfs_end_page_writeback(struct nfs_page *req)
{
struct inode *inode = page_file_mapping(req->wb_page)->host;
struct nfs_server *nfss = NFS_SERVER(inode);
bool is_done;
is_done = nfs_page_group_sync_on_bit(req, PG_WB_END);
nfs_unlock_request(req);
if (!is_done)
return;
end_page_writeback(req->wb_page);
if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
nfss->write_congested = 0;
}
/*
* nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests
*
* @destroy_list - request list (using wb_this_page) terminated by @old_head
* @old_head - the old head of the list
*
* All subrequests must be locked and removed from all lists, so at this point
* they are only "active" in this function, and possibly in nfs_wait_on_request
* with a reference held by some other context.
*/
static void
nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
struct nfs_page *old_head,
struct inode *inode)
{
while (destroy_list) {
struct nfs_page *subreq = destroy_list;
destroy_list = (subreq->wb_this_page == old_head) ?
NULL : subreq->wb_this_page;
/* Note: lock subreq in order to change subreq->wb_head */
nfs_page_set_headlock(subreq);
WARN_ON_ONCE(old_head != subreq->wb_head);
/* make sure old group is not used */
subreq->wb_this_page = subreq;
subreq->wb_head = subreq;
clear_bit(PG_REMOVE, &subreq->wb_flags);
/* Note: races with nfs_page_group_destroy() */
if (!kref_read(&subreq->wb_kref)) {
/* Check if we raced with nfs_page_group_destroy() */
if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags)) {
nfs_page_clear_headlock(subreq);
nfs_free_request(subreq);
} else
nfs_page_clear_headlock(subreq);
continue;
}
nfs_page_clear_headlock(subreq);
nfs_release_request(old_head);
if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
nfs_release_request(subreq);
atomic_long_dec(&NFS_I(inode)->nrequests);
}
/* subreq is now totally disconnected from page group or any
* write / commit lists. last chance to wake any waiters */
nfs_unlock_and_release_request(subreq);
}
}
/*
* nfs_join_page_group - destroy subrequests of the head req
* @head: the page used to lookup the "page group" of nfs_page structures
* @inode: Inode to which the request belongs.
*
* This function joins all sub requests to the head request by first
* locking all requests in the group, cancelling any pending operations
* and finally updating the head request to cover the whole range covered by
* the (former) group. All subrequests are removed from any write or commit
* lists, unlinked from the group and destroyed.
*/
void
nfs_join_page_group(struct nfs_page *head, struct inode *inode)
{
struct nfs_page *subreq;
struct nfs_page *destroy_list = NULL;
unsigned int pgbase, off, bytes;
pgbase = head->wb_pgbase;
bytes = head->wb_bytes;
off = head->wb_offset;
for (subreq = head->wb_this_page; subreq != head;
subreq = subreq->wb_this_page) {
/* Subrequests should always form a contiguous range */
if (pgbase > subreq->wb_pgbase) {
off -= pgbase - subreq->wb_pgbase;
bytes += pgbase - subreq->wb_pgbase;
pgbase = subreq->wb_pgbase;
}
bytes = max(subreq->wb_pgbase + subreq->wb_bytes
- pgbase, bytes);
}
/* Set the head request's range to cover the former page group */
head->wb_pgbase = pgbase;
head->wb_bytes = bytes;
head->wb_offset = off;
/* Now that all requests are locked, make sure they aren't on any list.
* Commit list removal accounting is done after locks are dropped */
subreq = head;
do {
nfs_clear_request_commit(subreq);
subreq = subreq->wb_this_page;
} while (subreq != head);
/* unlink subrequests from head, destroy them later */
if (head->wb_this_page != head) {
/* destroy list will be terminated by head */
destroy_list = head->wb_this_page;
head->wb_this_page = head;
}
nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
}
/*
* nfs_lock_and_join_requests - join all subreqs to the head req
* @page: the page used to lookup the "page group" of nfs_page structures
*
* This function joins all sub requests to the head request by first
* locking all requests in the group, cancelling any pending operations
* and finally updating the head request to cover the whole range covered by
* the (former) group. All subrequests are removed from any write or commit
* lists, unlinked from the group and destroyed.
*
* Returns a locked, referenced pointer to the head request - which after
* this call is guaranteed to be the only request associated with the page.
* Returns NULL if no requests are found for @page, or a ERR_PTR if an
* error was encountered.
*/
static struct nfs_page *
nfs_lock_and_join_requests(struct page *page)
{
struct inode *inode = page_file_mapping(page)->host;
struct nfs_page *head;
int ret;
/*
* A reference is taken only on the head request which acts as a
* reference to the whole page group - the group will not be destroyed
* until the head reference is released.
*/
head = nfs_find_and_lock_page_request(page);
if (IS_ERR_OR_NULL(head))
return head;
/* lock each request in the page group */
ret = nfs_page_group_lock_subrequests(head);
if (ret < 0) {
nfs_unlock_and_release_request(head);
return ERR_PTR(ret);
}
nfs_join_page_group(head, inode);
return head;
}
static void nfs_write_error(struct nfs_page *req, int error)
{
trace_nfs_write_error(page_file_mapping(req->wb_page)->host, req,
error);
nfs_mapping_set_error(req->wb_page, error);
nfs_inode_remove_request(req);
nfs_end_page_writeback(req);
nfs_release_request(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 page *page,
struct writeback_control *wbc,
struct nfs_pageio_descriptor *pgio)
{
struct nfs_page *req;
int ret = 0;
req = nfs_lock_and_join_requests(page);
if (!req)
goto out;
ret = PTR_ERR(req);
if (IS_ERR(req))
goto out;
nfs_set_page_writeback(page);
WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
/* If there is a fatal error that covers this write, just exit */
ret = pgio->pg_error;
if (nfs_error_is_fatal_on_server(ret))
goto out_launder;
ret = 0;
if (!nfs_pageio_add_request(pgio, req)) {
ret = pgio->pg_error;
/*
* Remove the problematic req upon fatal errors on the server
*/
if (nfs_error_is_fatal_on_server(ret))
goto out_launder;
if (wbc->sync_mode == WB_SYNC_NONE)
ret = AOP_WRITEPAGE_ACTIVATE;
redirty_page_for_writepage(wbc, page);
nfs_redirty_request(req);
pgio->pg_error = 0;
} else
nfs_add_stats(page_file_mapping(page)->host,
NFSIOS_WRITEPAGES, 1);
out:
return ret;
out_launder:
nfs_write_error(req, ret);
return 0;
}
static int nfs_do_writepage(struct page *page, struct writeback_control *wbc,
struct nfs_pageio_descriptor *pgio)
{
nfs_pageio_cond_complete(pgio, page_index(page));
return nfs_page_async_flush(page, wbc, pgio);
}
/*
* Write an mmapped page to the server.
*/
static int nfs_writepage_locked(struct page *page,
struct writeback_control *wbc)
{
struct nfs_pageio_descriptor pgio;
struct inode *inode = page_file_mapping(page)->host;
int err;
if (wbc->sync_mode == WB_SYNC_NONE &&
NFS_SERVER(inode)->write_congested)
return AOP_WRITEPAGE_ACTIVATE;
nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
nfs_pageio_init_write(&pgio, inode, 0,
false, &nfs_async_write_completion_ops);
err = nfs_do_writepage(page, wbc, &pgio);
pgio.pg_error = 0;
nfs_pageio_complete(&pgio);
return err;
}
int nfs_writepage(struct page *page, struct writeback_control *wbc)
{
int ret;
ret = nfs_writepage_locked(page, wbc);
if (ret != AOP_WRITEPAGE_ACTIVATE)
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);
if (ret != AOP_WRITEPAGE_ACTIVATE)
unlock_page(page);
return ret;
}
static void nfs_io_completion_commit(void *inode)
{
nfs_commit_inode(inode, 0);
}
int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
struct inode *inode = mapping->host;
struct nfs_pageio_descriptor pgio;
struct nfs_io_completion *ioc = NULL;
unsigned int mntflags = NFS_SERVER(inode)->flags;
int priority = 0;
int err;
if (wbc->sync_mode == WB_SYNC_NONE &&
NFS_SERVER(inode)->write_congested)
return 0;
nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
if (!(mntflags & NFS_MOUNT_WRITE_EAGER) || wbc->for_kupdate ||
wbc->for_background || wbc->for_sync || wbc->for_reclaim) {
ioc = nfs_io_completion_alloc(GFP_KERNEL);
if (ioc)
nfs_io_completion_init(ioc, nfs_io_completion_commit,
inode);
priority = wb_priority(wbc);
}
do {
nfs_pageio_init_write(&pgio, inode, priority, false,
&nfs_async_write_completion_ops);
pgio.pg_io_completion = ioc;
err = write_cache_pages(mapping, wbc, nfs_writepages_callback,
&pgio);
pgio.pg_error = 0;
nfs_pageio_complete(&pgio);
} while (err < 0 && !nfs_error_is_fatal(err));
nfs_io_completion_put(ioc);
if (err < 0)
goto out_err;
return 0;
out_err:
return err;
}
/*
* Insert a write request into an inode
*/
static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
{
struct address_space *mapping = page_file_mapping(req->wb_page);
struct nfs_inode *nfsi = NFS_I(inode);
WARN_ON_ONCE(req->wb_this_page != req);
/* Lock the request! */
nfs_lock_request(req);
/*
* Swap-space should not get truncated. Hence no need to plug the race
* with invalidate/truncate.
*/
spin_lock(&mapping->private_lock);
if (likely(!PageSwapCache(req->wb_page))) {
set_bit(PG_MAPPED, &req->wb_flags);
SetPagePrivate(req->wb_page);
set_page_private(req->wb_page, (unsigned long)req);
}
spin_unlock(&mapping->private_lock);
atomic_long_inc(&nfsi->nrequests);
/* this a head request for a page group - mark it as having an
* extra reference so sub groups can follow suit.
* This flag also informs pgio layer when to bump nrequests when
* adding subrequests. */
WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
kref_get(&req->wb_kref);
}
/*
* Remove a write request from an inode
*/
static void nfs_inode_remove_request(struct nfs_page *req)
{
struct address_space *mapping = page_file_mapping(req->wb_page);
struct inode *inode = mapping->host;
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_page *head;
if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
head = req->wb_head;
spin_lock(&mapping->private_lock);
if (likely(head->wb_page && !PageSwapCache(head->wb_page))) {
set_page_private(head->wb_page, 0);
ClearPagePrivate(head->wb_page);
clear_bit(PG_MAPPED, &head->wb_flags);
}
spin_unlock(&mapping->private_lock);
}
if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) {
nfs_release_request(req);
atomic_long_dec(&nfsi->nrequests);
}
}
static void
nfs_mark_request_dirty(struct nfs_page *req)
{
if (req->wb_page)
__set_page_dirty_nobuffers(req->wb_page);
}
/*
* nfs_page_search_commits_for_head_request_locked
*
* Search through commit lists on @inode for the head request for @page.
* Must be called while holding the inode (which is cinfo) lock.
*
* Returns the head request if found, or NULL if not found.
*/
static struct nfs_page *
nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
struct page *page)
{
struct nfs_page *freq, *t;
struct nfs_commit_info cinfo;
struct inode *inode = &nfsi->vfs_inode;
nfs_init_cinfo_from_inode(&cinfo, inode);
/* search through pnfs commit lists */
freq = pnfs_search_commit_reqs(inode, &cinfo, page);
if (freq)
return freq->wb_head;
/* Linearly search the commit list for the correct request */
list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
if (freq->wb_page == page)
return freq->wb_head;
}
return NULL;
}
/**
* nfs_request_add_commit_list_locked - add request to a commit list
* @req: pointer to a struct nfs_page
* @dst: commit list head
* @cinfo: holds list lock and accounting info
*
* This sets the PG_CLEAN bit, updates the cinfo count of
* number of outstanding requests requiring a commit as well as
* the MM page stats.
*
* The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
* nfs_page lock.
*/
void
nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
struct nfs_commit_info *cinfo)
{
set_bit(PG_CLEAN, &req->wb_flags);
nfs_list_add_request(req, dst);
atomic_long_inc(&cinfo->mds->ncommit);
}
EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
/**
* nfs_request_add_commit_list - add request to a commit list
* @req: pointer to a struct nfs_page
* @cinfo: holds list lock and accounting info
*
* This sets the PG_CLEAN bit, updates the cinfo count of
* number of outstanding requests requiring a commit as well as
* the MM page stats.
*
* The caller must _not_ hold the cinfo->lock, but must be
* holding the nfs_page lock.
*/
void
nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
{
mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
if (req->wb_page)
nfs_mark_page_unstable(req->wb_page, cinfo);
}
EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
/**
* nfs_request_remove_commit_list - Remove request from a commit list
* @req: pointer to a nfs_page
* @cinfo: holds list lock and accounting info
*
* This clears the PG_CLEAN bit, and updates the cinfo's count of
* number of outstanding requests requiring a commit
* It does not update the MM page stats.
*
* The caller _must_ hold the cinfo->lock and the nfs_page lock.
*/
void
nfs_request_remove_commit_list(struct nfs_page *req,
struct nfs_commit_info *cinfo)
{
if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
return;
nfs_list_remove_request(req);
atomic_long_dec(&cinfo->mds->ncommit);
}
EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
struct inode *inode)
{
cinfo->inode = inode;
cinfo->mds = &NFS_I(inode)->commit_info;
cinfo->ds = pnfs_get_ds_info(inode);
cinfo->dreq = NULL;
cinfo->completion_ops = &nfs_commit_completion_ops;
}
void nfs_init_cinfo(struct nfs_commit_info *cinfo,
struct inode *inode,
struct nfs_direct_req *dreq)
{
if (dreq)
nfs_init_cinfo_from_dreq(cinfo, dreq);
else
nfs_init_cinfo_from_inode(cinfo, inode);
}
EXPORT_SYMBOL_GPL(nfs_init_cinfo);
/*
* Add a request to the inode's commit list.
*/
void
nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
struct nfs_commit_info *cinfo, u32 ds_commit_idx)
{
if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
return;
nfs_request_add_commit_list(req, cinfo);
}
static void
nfs_clear_page_commit(struct page *page)
{
dec_node_page_state(page, NR_WRITEBACK);
dec_wb_stat(&inode_to_bdi(page_file_mapping(page)->host)->wb,
WB_WRITEBACK);
}
/* Called holding the request lock on @req */
static void
nfs_clear_request_commit(struct nfs_page *req)
{
if (test_bit(PG_CLEAN, &req->wb_flags)) {
struct nfs_open_context *ctx = nfs_req_openctx(req);
struct inode *inode = d_inode(ctx->dentry);
struct nfs_commit_info cinfo;
nfs_init_cinfo_from_inode(&cinfo, inode);
mutex_lock(&NFS_I(inode)->commit_mutex);
if (!pnfs_clear_request_commit(req, &cinfo)) {
nfs_request_remove_commit_list(req, &cinfo);
}
mutex_unlock(&NFS_I(inode)->commit_mutex);
nfs_clear_page_commit(req->wb_page);
}
}
int nfs_write_need_commit(struct nfs_pgio_header *hdr)
{
if (hdr->verf.committed == NFS_DATA_SYNC)
return hdr->lseg == NULL;
return hdr->verf.committed != NFS_FILE_SYNC;
}
static void nfs_async_write_init(struct nfs_pgio_header *hdr)
{
nfs_io_completion_get(hdr->io_completion);
}
static void nfs_write_completion(struct nfs_pgio_header *hdr)
{
struct nfs_commit_info cinfo;
unsigned long bytes = 0;
if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
goto out;
nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
while (!list_empty(&hdr->pages)) {
struct nfs_page *req = nfs_list_entry(hdr->pages.next);
bytes += req->wb_bytes;
nfs_list_remove_request(req);
if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
(hdr->good_bytes < bytes)) {
trace_nfs_comp_error(hdr->inode, req, hdr->error);
nfs_mapping_set_error(req->wb_page, hdr->error);
goto remove_req;
}
if (nfs_write_need_commit(hdr)) {
/* Reset wb_nio, since the write was successful. */
req->wb_nio = 0;
memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
nfs_mark_request_commit(req, hdr->lseg, &cinfo,
hdr->pgio_mirror_idx);
goto next;
}
remove_req:
nfs_inode_remove_request(req);
next:
nfs_end_page_writeback(req);
nfs_release_request(req);
}
out:
nfs_io_completion_put(hdr->io_completion);
hdr->release(hdr);
}
unsigned long
nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
{
return atomic_long_read(&cinfo->mds->ncommit);
}
/* NFS_I(cinfo->inode)->commit_mutex held by caller */
int
nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
struct nfs_commit_info *cinfo, int max)
{
struct nfs_page *req, *tmp;
int ret = 0;
list_for_each_entry_safe(req, tmp, src, wb_list) {
kref_get(&req->wb_kref);
if (!nfs_lock_request(req)) {
nfs_release_request(req);
continue;
}
nfs_request_remove_commit_list(req, cinfo);
clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
nfs_list_add_request(req, dst);
ret++;
if ((ret == max) && !cinfo->dreq)
break;
cond_resched();
}
return ret;
}
EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
/*
* nfs_scan_commit - Scan an inode for commit requests
* @inode: NFS inode to scan
* @dst: mds destination list
* @cinfo: mds and ds lists of reqs ready to commit
*
* Moves requests from the inode's 'commit' request list.
* The requests are *not* checked to ensure that they form a contiguous set.
*/
int
nfs_scan_commit(struct inode *inode, struct list_head *dst,
struct nfs_commit_info *cinfo)
{
int ret = 0;
if (!atomic_long_read(&cinfo->mds->ncommit))
return 0;
mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
const int max = INT_MAX;
ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
cinfo, max);
ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
}
mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
return ret;
}
/*
* 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;
end = offset + bytes;
req = nfs_lock_and_join_requests(page);
if (IS_ERR_OR_NULL(req))
return req;
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;
/* 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;
req->wb_nio = 0;
return req;
out_flushme:
/*
* Note: we mark the request dirty here because
* nfs_lock_and_join_requests() cannot preserve
* commit flags, so we have to replay the write.
*/
nfs_mark_request_dirty(req);
nfs_unlock_and_release_request(req);
error = nfs_wb_page(inode, page);
return (error < 0) ? ERR_PTR(error) : NULL;
}
/*
* 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_file_mapping(page)->host;
struct nfs_page *req;
req = nfs_try_to_update_request(inode, page, offset, bytes);
if (req != NULL)
goto out;
req = nfs_create_request(ctx, page, offset, bytes);
if (IS_ERR(req))
goto out;
nfs_inode_add_request(inode, req);
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(req);
nfs_mark_request_dirty(req);
nfs_unlock_and_release_request(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_lock_context *l_ctx;
struct file_lock_context *flctx = file_inode(file)->i_flctx;
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_head_request(page);
if (req == NULL)
return 0;
l_ctx = req->wb_lock_context;
do_flush = req->wb_page != page ||
!nfs_match_open_context(nfs_req_openctx(req), ctx);
if (l_ctx && flctx &&
!(list_empty_careful(&flctx->flc_posix) &&
list_empty_careful(&flctx->flc_flock))) {
do_flush |= l_ctx->lockowner != current->files;
}
nfs_release_request(req);
if (!do_flush)
return 0;
status = nfs_wb_page(page_file_mapping(page)->host, page);
} while (status == 0);
return status;
}
/*
* Avoid buffered writes when a open context credential's key would
* expire soon.
*
* Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
*
* Return 0 and set a credential flag which triggers the inode to flush
* and performs NFS_FILE_SYNC writes if the key will expired within
* RPC_KEY_EXPIRE_TIMEO.
*/
int
nfs_key_timeout_notify(struct file *filp, struct inode *inode)
{
struct nfs_open_context *ctx = nfs_file_open_context(filp);
if (nfs_ctx_key_to_expire(ctx, inode) &&
!rcu_access_pointer(ctx->ll_cred))
/* Already expired! */
return -EACCES;
return 0;
}
/*
* Test if the open context credential key is marked to expire soon.
*/
bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx, struct inode *inode)
{
struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
struct rpc_cred *cred, *new, *old = NULL;
struct auth_cred acred = {
.cred = ctx->cred,
};
bool ret = false;
rcu_read_lock();
cred = rcu_dereference(ctx->ll_cred);
if (cred && !(cred->cr_ops->crkey_timeout &&
cred->cr_ops->crkey_timeout(cred)))
goto out;
rcu_read_unlock();
new = auth->au_ops->lookup_cred(auth, &acred, 0);
if (new == cred) {
put_rpccred(new);
return true;
}
if (IS_ERR_OR_NULL(new)) {
new = NULL;
ret = true;
} else if (new->cr_ops->crkey_timeout &&
new->cr_ops->crkey_timeout(new))
ret = true;
rcu_read_lock();
old = rcu_dereference_protected(xchg(&ctx->ll_cred,
RCU_INITIALIZER(new)), 1);
out:
rcu_read_unlock();
put_rpccred(old);
return ret;
}
/*
* 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 bool nfs_write_pageuptodate(struct page *page, struct inode *inode,
unsigned int pagelen)
{
struct nfs_inode *nfsi = NFS_I(inode);
if (nfs_have_delegated_attributes(inode))
goto out;
if (nfsi->cache_validity &
(NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE))
return false;
smp_rmb();
if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags) && pagelen != 0)
return false;
out:
if (nfsi->cache_validity & NFS_INO_INVALID_DATA && pagelen != 0)
return false;
return PageUptodate(page) != 0;
}
static bool
is_whole_file_wrlock(struct file_lock *fl)
{
return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
fl->fl_type == F_WRLCK;
}
/* If we know the page is up to date, and we're not using byte range locks (or
* if we have the whole file locked for writing), it may be more efficient to
* extend the write to cover the entire page in order to avoid fragmentation
* inefficiencies.
*
* If the file is opened for synchronous writes then we can just skip the rest
* of the checks.
*/
static int nfs_can_extend_write(struct file *file, struct page *page,
struct inode *inode, unsigned int pagelen)
{
int ret;
struct file_lock_context *flctx = inode->i_flctx;
struct file_lock *fl;
if (file->f_flags & O_DSYNC)
return 0;
if (!nfs_write_pageuptodate(page, inode, pagelen))
return 0;
if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
return 1;
if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
list_empty_careful(&flctx->flc_posix)))
return 1;
/* Check to see if there are whole file write locks */
ret = 0;
spin_lock(&flctx->flc_lock);
if (!list_empty(&flctx->flc_posix)) {
fl = list_first_entry(&flctx->flc_posix, struct file_lock,
fl_list);
if (is_whole_file_wrlock(fl))
ret = 1;
} else if (!list_empty(&flctx->flc_flock)) {
fl = list_first_entry(&flctx->flc_flock, struct file_lock,
fl_list);
if (fl->fl_type == F_WRLCK)
ret = 1;
}
spin_unlock(&flctx->flc_lock);
return ret;
}
/*
* 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 address_space *mapping = page_file_mapping(page);
struct inode *inode = mapping->host;
unsigned int pagelen = nfs_page_length(page);
int status = 0;
nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
dprintk("NFS: nfs_updatepage(%pD2 %d@%lld)\n",
file, count, (long long)(page_file_offset(page) + offset));
if (!count)
goto out;
if (nfs_can_extend_write(file, page, inode, pagelen)) {
count = max(count + offset, pagelen);
offset = 0;
}
status = nfs_writepage_setup(ctx, page, offset, count);
if (status < 0)
nfs_set_pageerror(mapping);
out:
dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n",
status, (long long)i_size_read(inode));
return status;
}
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;
}
static void nfs_initiate_write(struct nfs_pgio_header *hdr,
struct rpc_message *msg,
const struct nfs_rpc_ops *rpc_ops,
struct rpc_task_setup *task_setup_data, int how)
{
int priority = flush_task_priority(how);
if (IS_SWAPFILE(hdr->inode))
task_setup_data->flags |= RPC_TASK_SWAPPER;
task_setup_data->priority = priority;
rpc_ops->write_setup(hdr, msg, &task_setup_data->rpc_client);
trace_nfs_initiate_write(hdr);
}
/* 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 nfs_inode *nfsi = NFS_I(page_file_mapping(req->wb_page)->host);
/* Bump the transmission count */
req->wb_nio++;
nfs_mark_request_dirty(req);
atomic_long_inc(&nfsi->redirtied_pages);
nfs_end_page_writeback(req);
nfs_release_request(req);
}
static void nfs_async_write_error(struct list_head *head, int error)
{
struct nfs_page *req;
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
if (nfs_error_is_fatal_on_server(error))
nfs_write_error(req, error);
else
nfs_redirty_request(req);
}
}
static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
{
nfs_async_write_error(&hdr->pages, 0);
}
static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
.init_hdr = nfs_async_write_init,
.error_cleanup = nfs_async_write_error,
.completion = nfs_write_completion,
.reschedule_io = nfs_async_write_reschedule_io,
};
void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
struct inode *inode, int ioflags, bool force_mds,
const struct nfs_pgio_completion_ops *compl_ops)
{
struct nfs_server *server = NFS_SERVER(inode);
const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
#ifdef CONFIG_NFS_V4_1
if (server->pnfs_curr_ld && !force_mds)
pg_ops = server->pnfs_curr_ld->pg_write_ops;
#endif
nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
server->wsize, ioflags);
}
EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
{
struct nfs_pgio_mirror *mirror;
if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
pgio->pg_ops->pg_cleanup(pgio);
pgio->pg_ops = &nfs_pgio_rw_ops;
nfs_pageio_stop_mirroring(pgio);
mirror = &pgio->pg_mirrors[0];
mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
}
EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
void nfs_commit_prepare(struct rpc_task *task, void *calldata)
{
struct nfs_commit_data *data = calldata;
NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
}
static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
struct nfs_fattr *fattr)
{
struct nfs_pgio_args *argp = &hdr->args;
struct nfs_pgio_res *resp = &hdr->res;
u64 size = argp->offset + resp->count;
if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
fattr->size = size;
if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
return;
}
if (size != fattr->size)
return;
/* Set attribute barrier */
nfs_fattr_set_barrier(fattr);
/* ...and update size */
fattr->valid |= NFS_ATTR_FATTR_SIZE;
}
void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
{
struct nfs_fattr *fattr = &hdr->fattr;
struct inode *inode = hdr->inode;
spin_lock(&inode->i_lock);
nfs_writeback_check_extend(hdr, fattr);
nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
spin_unlock(&inode->i_lock);
}
EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
/*
* This function is called when the WRITE call is complete.
*/
static int nfs_writeback_done(struct rpc_task *task,
struct nfs_pgio_header *hdr,
struct inode *inode)
{
int 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(inode)->write_done(task, hdr);
if (status != 0)
return status;
nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
trace_nfs_writeback_done(task, hdr);
if (task->tk_status >= 0) {
enum nfs3_stable_how committed = hdr->res.verf->committed;
if (committed == NFS_UNSTABLE) {
/*
* We have some uncommitted data on the server at
* this point, so ensure that we keep track of that
* fact irrespective of what later writes do.
*/
set_bit(NFS_IOHDR_UNSTABLE_WRITES, &hdr->flags);
}
if (committed < hdr->args.stable) {
/* 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(inode)->nfs_client->cl_hostname,
committed, hdr->args.stable);
complain = jiffies + 300 * HZ;
}
}
}
/* Deal with the suid/sgid bit corner case */
if (nfs_should_remove_suid(inode)) {
spin_lock(&inode->i_lock);
nfs_set_cache_invalid(inode, NFS_INO_INVALID_MODE);
spin_unlock(&inode->i_lock);
}
return 0;
}
/*
* This function is called when the WRITE call is complete.
*/
static void nfs_writeback_result(struct rpc_task *task,
struct nfs_pgio_header *hdr)
{
struct nfs_pgio_args *argp = &hdr->args;
struct nfs_pgio_res *resp = &hdr->res;
if (resp->count < argp->count) {
static unsigned long complain;
/* This a short write! */
nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
/* Has the server at least made some progress? */
if (resp->count == 0) {
if (time_before(complain, jiffies)) {
printk(KERN_WARNING
"NFS: Server wrote zero bytes, expected %u.\n",
argp->count);
complain = jiffies + 300 * HZ;
}
nfs_set_pgio_error(hdr, -EIO, argp->offset);
task->tk_status = -EIO;
return;
}
/* For non rpc-based layout drivers, retry-through-MDS */
if (!task->tk_ops) {
hdr->pnfs_error = -EAGAIN;
return;
}
/* Was this an NFSv2 write or an NFSv3 stable write? */
if (resp->verf->committed != NFS_UNSTABLE) {
/* Resend from where the server left off */
hdr->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;
}
resp->count = 0;
resp->verf->committed = 0;
rpc_restart_call_prepare(task);
}
}
static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
{
return wait_var_event_killable(&cinfo->rpcs_out,
!atomic_read(&cinfo->rpcs_out));
}
static void nfs_commit_begin(struct nfs_mds_commit_info *cinfo)
{
atomic_inc(&cinfo->rpcs_out);
}
bool nfs_commit_end(struct nfs_mds_commit_info *cinfo)
{
if (atomic_dec_and_test(&cinfo->rpcs_out)) {
wake_up_var(&cinfo->rpcs_out);
return true;
}
return false;
}
void nfs_commitdata_release(struct nfs_commit_data *data)
{
put_nfs_open_context(data->context);
nfs_commit_free(data);
}
EXPORT_SYMBOL_GPL(nfs_commitdata_release);
int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
const struct nfs_rpc_ops *nfs_ops,
const struct rpc_call_ops *call_ops,
int how, int flags)
{
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 | flags,
.priority = priority,
};
if (nfs_server_capable(data->inode, NFS_CAP_MOVEABLE))
task_setup_data.flags |= RPC_TASK_MOVEABLE;
/* Set up the initial task struct. */
nfs_ops->commit_setup(data, &msg, &task_setup_data.rpc_client);
trace_nfs_initiate_commit(data);
dprintk("NFS: initiated commit call\n");
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);
static loff_t nfs_get_lwb(struct list_head *head)
{
loff_t lwb = 0;
struct nfs_page *req;
list_for_each_entry(req, head, wb_list)
if (lwb < (req_offset(req) + req->wb_bytes))
lwb = req_offset(req) + req->wb_bytes;
return lwb;
}
/*
* Set up the argument/result storage required for the RPC call.
*/
void nfs_init_commit(struct nfs_commit_data *data,
struct list_head *head,
struct pnfs_layout_segment *lseg,
struct nfs_commit_info *cinfo)
{
struct nfs_page *first;
struct nfs_open_context *ctx;
struct inode *inode;
/* Set up the RPC argument and reply structs
* NB: take care not to mess about with data->commit et al. */
if (head)
list_splice_init(head, &data->pages);
first = nfs_list_entry(data->pages.next);
ctx = nfs_req_openctx(first);
inode = d_inode(ctx->dentry);
data->inode = inode;
data->cred = ctx->cred;
data->lseg = lseg; /* reference transferred */
/* only set lwb for pnfs commit */
if (lseg)
data->lwb = nfs_get_lwb(&data->pages);
data->mds_ops = &nfs_commit_ops;
data->completion_ops = cinfo->completion_ops;
data->dreq = cinfo->dreq;
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->context = get_nfs_open_context(ctx);
data->res.fattr = &data->fattr;
data->res.verf = &data->verf;
nfs_fattr_init(&data->fattr);
nfs_commit_begin(cinfo->mds);
}
EXPORT_SYMBOL_GPL(nfs_init_commit);
void nfs_retry_commit(struct list_head *page_list,
struct pnfs_layout_segment *lseg,
struct nfs_commit_info *cinfo,
u32 ds_commit_idx)
{
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, cinfo, ds_commit_idx);
if (!cinfo->dreq)
nfs_clear_page_commit(req->wb_page);
nfs_unlock_and_release_request(req);
}
}
EXPORT_SYMBOL_GPL(nfs_retry_commit);
static void
nfs_commit_resched_write(struct nfs_commit_info *cinfo,
struct nfs_page *req)
{
__set_page_dirty_nobuffers(req->wb_page);
}
/*
* Commit dirty pages
*/
static int
nfs_commit_list(struct inode *inode, struct list_head *head, int how,
struct nfs_commit_info *cinfo)
{
struct nfs_commit_data *data;
unsigned short task_flags = 0;
/* another commit raced with us */
if (list_empty(head))
return 0;
data = nfs_commitdata_alloc();
if (!data) {
nfs_retry_commit(head, NULL, cinfo, -1);
return -ENOMEM;
}
/* Set up the argument struct */
nfs_init_commit(data, head, NULL, cinfo);
if (NFS_SERVER(inode)->nfs_client->cl_minorversion)
task_flags = RPC_TASK_MOVEABLE;
return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
data->mds_ops, how,
RPC_TASK_CRED_NOREF | task_flags);
}
/*
* COMMIT call returned
*/
static void nfs_commit_done(struct rpc_task *task, void *calldata)
{
struct nfs_commit_data *data = calldata;
/* Call the NFS version-specific code */
NFS_PROTO(data->inode)->commit_done(task, data);
trace_nfs_commit_done(task, data);
}
static void nfs_commit_release_pages(struct nfs_commit_data *data)
{
const struct nfs_writeverf *verf = data->res.verf;
struct nfs_page *req;
int status = data->task.tk_status;
struct nfs_commit_info cinfo;
struct nfs_server *nfss;
while (!list_empty(&data->pages)) {
req = nfs_list_entry(data->pages.next);
nfs_list_remove_request(req);
if (req->wb_page)
nfs_clear_page_commit(req->wb_page);
dprintk("NFS: commit (%s/%llu %d@%lld)",
nfs_req_openctx(req)->dentry->d_sb->s_id,
(unsigned long long)NFS_FILEID(d_inode(nfs_req_openctx(req)->dentry)),
req->wb_bytes,
(long long)req_offset(req));
if (status < 0) {
if (req->wb_page) {
trace_nfs_commit_error(data->inode, req,
status);
nfs_mapping_set_error(req->wb_page, status);
nfs_inode_remove_request(req);
}
dprintk_cont(", error = %d\n", status);
goto next;
}
/* Okay, COMMIT succeeded, apparently. Check the verifier
* returned by the server against all stored verfs. */
if (nfs_write_match_verf(verf, req)) {
/* We have a match */
if (req->wb_page)
nfs_inode_remove_request(req);
dprintk_cont(" OK\n");
goto next;
}
/* We have a mismatch. Write the page again */
dprintk_cont(" mismatch\n");
nfs_mark_request_dirty(req);
atomic_long_inc(&NFS_I(data->inode)->redirtied_pages);
next:
nfs_unlock_and_release_request(req);
/* Latency breaker */
cond_resched();
}
nfss = NFS_SERVER(data->inode);
if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
nfss->write_congested = 0;
nfs_init_cinfo(&cinfo, data->inode, data->dreq);
nfs_commit_end(cinfo.mds);
}
static void nfs_commit_release(void *calldata)
{
struct nfs_commit_data *data = calldata;
data->completion_ops->completion(data);
nfs_commitdata_release(calldata);
}
static const struct rpc_call_ops nfs_commit_ops = {
.rpc_call_prepare = nfs_commit_prepare,
.rpc_call_done = nfs_commit_done,
.rpc_release = nfs_commit_release,
};
static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
.completion = nfs_commit_release_pages,
.resched_write = nfs_commit_resched_write,
};
int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
int how, struct nfs_commit_info *cinfo)
{
int status;
status = pnfs_commit_list(inode, head, how, cinfo);
if (status == PNFS_NOT_ATTEMPTED)
status = nfs_commit_list(inode, head, how, cinfo);
return status;
}
static int __nfs_commit_inode(struct inode *inode, int how,
struct writeback_control *wbc)
{
LIST_HEAD(head);
struct nfs_commit_info cinfo;
int may_wait = how & FLUSH_SYNC;
int ret, nscan;
how &= ~FLUSH_SYNC;
nfs_init_cinfo_from_inode(&cinfo, inode);
nfs_commit_begin(cinfo.mds);
for (;;) {
ret = nscan = nfs_scan_commit(inode, &head, &cinfo);
if (ret <= 0)
break;
ret = nfs_generic_commit_list(inode, &head, how, &cinfo);
if (ret < 0)
break;
ret = 0;
if (wbc && wbc->sync_mode == WB_SYNC_NONE) {
if (nscan < wbc->nr_to_write)
wbc->nr_to_write -= nscan;
else
wbc->nr_to_write = 0;
}
if (nscan < INT_MAX)
break;
cond_resched();
}
nfs_commit_end(cinfo.mds);
if (ret || !may_wait)
return ret;
return wait_on_commit(cinfo.mds);
}
int nfs_commit_inode(struct inode *inode, int how)
{
return __nfs_commit_inode(inode, how, NULL);
}
EXPORT_SYMBOL_GPL(nfs_commit_inode);
int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
{
struct nfs_inode *nfsi = NFS_I(inode);
int flags = FLUSH_SYNC;
int ret = 0;
if (wbc->sync_mode == WB_SYNC_NONE) {
/* no commits means nothing needs to be done */
if (!atomic_long_read(&nfsi->commit_info.ncommit))
goto check_requests_outstanding;
/* Don't commit yet if this is a non-blocking flush and there
* are a lot of outstanding writes for this mapping.
*/
if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
goto out_mark_dirty;
/* don't wait for the COMMIT response */
flags = 0;
}
ret = __nfs_commit_inode(inode, flags, wbc);
if (!ret) {
if (flags & FLUSH_SYNC)
return 0;
} else if (atomic_long_read(&nfsi->commit_info.ncommit))
goto out_mark_dirty;
check_requests_outstanding:
if (!atomic_read(&nfsi->commit_info.rpcs_out))
return ret;
out_mark_dirty:
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
return ret;
}
EXPORT_SYMBOL_GPL(nfs_write_inode);
/*
* Wrapper for filemap_write_and_wait_range()
*
* Needed for pNFS in order to ensure data becomes visible to the
* client.
*/
int nfs_filemap_write_and_wait_range(struct address_space *mapping,
loff_t lstart, loff_t lend)
{
int ret;
ret = filemap_write_and_wait_range(mapping, lstart, lend);
if (ret == 0)
ret = pnfs_sync_inode(mapping->host, true);
return ret;
}
EXPORT_SYMBOL_GPL(nfs_filemap_write_and_wait_range);
/*
* flush the inode to disk.
*/
int nfs_wb_all(struct inode *inode)
{
int ret;
trace_nfs_writeback_inode_enter(inode);
ret = filemap_write_and_wait(inode->i_mapping);
if (ret)
goto out;
ret = nfs_commit_inode(inode, FLUSH_SYNC);
if (ret < 0)
goto out;
pnfs_sync_inode(inode, true);
ret = 0;
out:
trace_nfs_writeback_inode_exit(inode, ret);
return ret;
}
EXPORT_SYMBOL_GPL(nfs_wb_all);
int nfs_wb_folio_cancel(struct inode *inode, struct folio *folio)
{
struct nfs_page *req;
int ret = 0;
folio_wait_writeback(folio);
/* blocking call to cancel all requests and join to a single (head)
* request */
req = nfs_lock_and_join_requests(&folio->page);
if (IS_ERR(req)) {
ret = PTR_ERR(req);
} else if (req) {
/* all requests from this folio have been cancelled by
* nfs_lock_and_join_requests, so just remove the head
* request from the inode / page_private pointer and
* release it */
nfs_inode_remove_request(req);
nfs_unlock_and_release_request(req);
}
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_file_offset(page);
loff_t range_end = range_start + (loff_t)(PAGE_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;
trace_nfs_writeback_page_enter(inode);
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;
}
ret = 0;
if (!PagePrivate(page))
break;
ret = nfs_commit_inode(inode, FLUSH_SYNC);
if (ret < 0)
goto out_error;
}
out_error:
trace_nfs_writeback_page_exit(inode, ret);
return ret;
}
#ifdef CONFIG_MIGRATION
int nfs_migrate_folio(struct address_space *mapping, struct folio *dst,
struct folio *src, enum migrate_mode mode)
{
/*
* If the private flag is set, the folio 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 folio lock.
*/
if (folio_test_private(src))
return -EBUSY;
if (folio_test_fscache(src)) {
if (mode == MIGRATE_ASYNC)
return -EBUSY;
folio_wait_fscache(src);
}
return migrate_folio(mapping, dst, src, mode);
}
#endif
int __init nfs_init_writepagecache(void)
{
nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
sizeof(struct nfs_pgio_header),
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)
goto out_destroy_write_cache;
nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
sizeof(struct nfs_commit_data),
0, SLAB_HWCACHE_ALIGN,
NULL);
if (nfs_cdata_cachep == NULL)
goto out_destroy_write_mempool;
nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
nfs_cdata_cachep);
if (nfs_commit_mempool == NULL)
goto out_destroy_commit_cache;
/*
* 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;
out_destroy_commit_cache:
kmem_cache_destroy(nfs_cdata_cachep);
out_destroy_write_mempool:
mempool_destroy(nfs_wdata_mempool);
out_destroy_write_cache:
kmem_cache_destroy(nfs_wdata_cachep);
return -ENOMEM;
}
void nfs_destroy_writepagecache(void)
{
mempool_destroy(nfs_commit_mempool);
kmem_cache_destroy(nfs_cdata_cachep);
mempool_destroy(nfs_wdata_mempool);
kmem_cache_destroy(nfs_wdata_cachep);
}
static const struct nfs_rw_ops nfs_rw_write_ops = {
.rw_alloc_header = nfs_writehdr_alloc,
.rw_free_header = nfs_writehdr_free,
.rw_done = nfs_writeback_done,
.rw_result = nfs_writeback_result,
.rw_initiate = nfs_initiate_write,
};