blob: dc66ff15dd16e40d6c6d086e72e12b8c38105d19 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/* handling of writes to regular files and writing back to the server
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/backing-dev.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/pagevec.h>
#include <linux/netfs.h>
#include <linux/fscache.h>
#include "internal.h"
/*
* mark a page as having been made dirty and thus needing writeback
*/
int afs_set_page_dirty(struct page *page)
{
_enter("");
return __set_page_dirty_nobuffers(page);
}
/*
* prepare to perform part of a write to a page
*/
int afs_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **_page, void **fsdata)
{
struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
struct page *page;
unsigned long priv;
unsigned f, from;
unsigned t, to;
pgoff_t index;
int ret;
_enter("{%llx:%llu},%llx,%x",
vnode->fid.vid, vnode->fid.vnode, pos, len);
/* Prefetch area to be written into the cache if we're caching this
* file. We need to do this before we get a lock on the page in case
* there's more than one writer competing for the same cache block.
*/
ret = netfs_write_begin(file, mapping, pos, len, flags, &page, fsdata,
&afs_req_ops, NULL);
if (ret < 0)
return ret;
index = page->index;
from = pos - index * PAGE_SIZE;
to = from + len;
try_again:
/* See if this page is already partially written in a way that we can
* merge the new write with.
*/
if (PagePrivate(page)) {
priv = page_private(page);
f = afs_page_dirty_from(page, priv);
t = afs_page_dirty_to(page, priv);
ASSERTCMP(f, <=, t);
if (PageWriteback(page)) {
trace_afs_page_dirty(vnode, tracepoint_string("alrdy"), page);
goto flush_conflicting_write;
}
/* If the file is being filled locally, allow inter-write
* spaces to be merged into writes. If it's not, only write
* back what the user gives us.
*/
if (!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags) &&
(to < f || from > t))
goto flush_conflicting_write;
}
*_page = page;
_leave(" = 0");
return 0;
/* The previous write and this write aren't adjacent or overlapping, so
* flush the page out.
*/
flush_conflicting_write:
_debug("flush conflict");
ret = write_one_page(page);
if (ret < 0)
goto error;
ret = lock_page_killable(page);
if (ret < 0)
goto error;
goto try_again;
error:
put_page(page);
_leave(" = %d", ret);
return ret;
}
/*
* finalise part of a write to a page
*/
int afs_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
unsigned long priv;
unsigned int f, from = pos & (thp_size(page) - 1);
unsigned int t, to = from + copied;
loff_t i_size, maybe_i_size;
_enter("{%llx:%llu},{%lx}",
vnode->fid.vid, vnode->fid.vnode, page->index);
if (copied == 0)
goto out;
maybe_i_size = pos + copied;
i_size = i_size_read(&vnode->vfs_inode);
if (maybe_i_size > i_size) {
write_seqlock(&vnode->cb_lock);
i_size = i_size_read(&vnode->vfs_inode);
if (maybe_i_size > i_size)
i_size_write(&vnode->vfs_inode, maybe_i_size);
write_sequnlock(&vnode->cb_lock);
}
ASSERT(PageUptodate(page));
if (PagePrivate(page)) {
priv = page_private(page);
f = afs_page_dirty_from(page, priv);
t = afs_page_dirty_to(page, priv);
if (from < f)
f = from;
if (to > t)
t = to;
priv = afs_page_dirty(page, f, t);
set_page_private(page, priv);
trace_afs_page_dirty(vnode, tracepoint_string("dirty+"), page);
} else {
priv = afs_page_dirty(page, from, to);
attach_page_private(page, (void *)priv);
trace_afs_page_dirty(vnode, tracepoint_string("dirty"), page);
}
if (set_page_dirty(page))
_debug("dirtied %lx", page->index);
out:
unlock_page(page);
put_page(page);
return copied;
}
/*
* kill all the pages in the given range
*/
static void afs_kill_pages(struct address_space *mapping,
loff_t start, loff_t len)
{
struct afs_vnode *vnode = AFS_FS_I(mapping->host);
struct pagevec pv;
unsigned int loop, psize;
_enter("{%llx:%llu},%llx @%llx",
vnode->fid.vid, vnode->fid.vnode, len, start);
pagevec_init(&pv);
do {
_debug("kill %llx @%llx", len, start);
pv.nr = find_get_pages_contig(mapping, start / PAGE_SIZE,
PAGEVEC_SIZE, pv.pages);
if (pv.nr == 0)
break;
for (loop = 0; loop < pv.nr; loop++) {
struct page *page = pv.pages[loop];
if (page->index * PAGE_SIZE >= start + len)
break;
psize = thp_size(page);
start += psize;
len -= psize;
ClearPageUptodate(page);
end_page_writeback(page);
lock_page(page);
generic_error_remove_page(mapping, page);
unlock_page(page);
}
__pagevec_release(&pv);
} while (len > 0);
_leave("");
}
/*
* Redirty all the pages in a given range.
*/
static void afs_redirty_pages(struct writeback_control *wbc,
struct address_space *mapping,
loff_t start, loff_t len)
{
struct afs_vnode *vnode = AFS_FS_I(mapping->host);
struct pagevec pv;
unsigned int loop, psize;
_enter("{%llx:%llu},%llx @%llx",
vnode->fid.vid, vnode->fid.vnode, len, start);
pagevec_init(&pv);
do {
_debug("redirty %llx @%llx", len, start);
pv.nr = find_get_pages_contig(mapping, start / PAGE_SIZE,
PAGEVEC_SIZE, pv.pages);
if (pv.nr == 0)
break;
for (loop = 0; loop < pv.nr; loop++) {
struct page *page = pv.pages[loop];
if (page->index * PAGE_SIZE >= start + len)
break;
psize = thp_size(page);
start += psize;
len -= psize;
redirty_page_for_writepage(wbc, page);
end_page_writeback(page);
}
__pagevec_release(&pv);
} while (len > 0);
_leave("");
}
/*
* completion of write to server
*/
static void afs_pages_written_back(struct afs_vnode *vnode, loff_t start, unsigned int len)
{
struct address_space *mapping = vnode->vfs_inode.i_mapping;
struct page *page;
pgoff_t end;
XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE);
_enter("{%llx:%llu},{%x @%llx}",
vnode->fid.vid, vnode->fid.vnode, len, start);
rcu_read_lock();
end = (start + len - 1) / PAGE_SIZE;
xas_for_each(&xas, page, end) {
if (!PageWriteback(page)) {
kdebug("bad %x @%llx page %lx %lx", len, start, page->index, end);
ASSERT(PageWriteback(page));
}
trace_afs_page_dirty(vnode, tracepoint_string("clear"), page);
detach_page_private(page);
page_endio(page, true, 0);
}
rcu_read_unlock();
afs_prune_wb_keys(vnode);
_leave("");
}
/*
* Find a key to use for the writeback. We cached the keys used to author the
* writes on the vnode. *_wbk will contain the last writeback key used or NULL
* and we need to start from there if it's set.
*/
static int afs_get_writeback_key(struct afs_vnode *vnode,
struct afs_wb_key **_wbk)
{
struct afs_wb_key *wbk = NULL;
struct list_head *p;
int ret = -ENOKEY, ret2;
spin_lock(&vnode->wb_lock);
if (*_wbk)
p = (*_wbk)->vnode_link.next;
else
p = vnode->wb_keys.next;
while (p != &vnode->wb_keys) {
wbk = list_entry(p, struct afs_wb_key, vnode_link);
_debug("wbk %u", key_serial(wbk->key));
ret2 = key_validate(wbk->key);
if (ret2 == 0) {
refcount_inc(&wbk->usage);
_debug("USE WB KEY %u", key_serial(wbk->key));
break;
}
wbk = NULL;
if (ret == -ENOKEY)
ret = ret2;
p = p->next;
}
spin_unlock(&vnode->wb_lock);
if (*_wbk)
afs_put_wb_key(*_wbk);
*_wbk = wbk;
return 0;
}
static void afs_store_data_success(struct afs_operation *op)
{
struct afs_vnode *vnode = op->file[0].vnode;
op->ctime = op->file[0].scb.status.mtime_client;
afs_vnode_commit_status(op, &op->file[0]);
if (op->error == 0) {
if (!op->store.laundering)
afs_pages_written_back(vnode, op->store.pos, op->store.size);
afs_stat_v(vnode, n_stores);
atomic_long_add(op->store.size, &afs_v2net(vnode)->n_store_bytes);
}
}
static const struct afs_operation_ops afs_store_data_operation = {
.issue_afs_rpc = afs_fs_store_data,
.issue_yfs_rpc = yfs_fs_store_data,
.success = afs_store_data_success,
};
/*
* write to a file
*/
static int afs_store_data(struct afs_vnode *vnode, struct iov_iter *iter, loff_t pos,
bool laundering)
{
struct afs_operation *op;
struct afs_wb_key *wbk = NULL;
loff_t size = iov_iter_count(iter), i_size;
int ret = -ENOKEY;
_enter("%s{%llx:%llu.%u},%llx,%llx",
vnode->volume->name,
vnode->fid.vid,
vnode->fid.vnode,
vnode->fid.unique,
size, pos);
ret = afs_get_writeback_key(vnode, &wbk);
if (ret) {
_leave(" = %d [no keys]", ret);
return ret;
}
op = afs_alloc_operation(wbk->key, vnode->volume);
if (IS_ERR(op)) {
afs_put_wb_key(wbk);
return -ENOMEM;
}
i_size = i_size_read(&vnode->vfs_inode);
afs_op_set_vnode(op, 0, vnode);
op->file[0].dv_delta = 1;
op->store.write_iter = iter;
op->store.pos = pos;
op->store.size = size;
op->store.i_size = max(pos + size, i_size);
op->store.laundering = laundering;
op->mtime = vnode->vfs_inode.i_mtime;
op->flags |= AFS_OPERATION_UNINTR;
op->ops = &afs_store_data_operation;
try_next_key:
afs_begin_vnode_operation(op);
afs_wait_for_operation(op);
switch (op->error) {
case -EACCES:
case -EPERM:
case -ENOKEY:
case -EKEYEXPIRED:
case -EKEYREJECTED:
case -EKEYREVOKED:
_debug("next");
ret = afs_get_writeback_key(vnode, &wbk);
if (ret == 0) {
key_put(op->key);
op->key = key_get(wbk->key);
goto try_next_key;
}
break;
}
afs_put_wb_key(wbk);
_leave(" = %d", op->error);
return afs_put_operation(op);
}
/*
* Extend the region to be written back to include subsequent contiguously
* dirty pages if possible, but don't sleep while doing so.
*
* If this page holds new content, then we can include filler zeros in the
* writeback.
*/
static void afs_extend_writeback(struct address_space *mapping,
struct afs_vnode *vnode,
long *_count,
loff_t start,
loff_t max_len,
bool new_content,
unsigned int *_len)
{
struct pagevec pvec;
struct page *page;
unsigned long priv;
unsigned int psize, filler = 0;
unsigned int f, t;
loff_t len = *_len;
pgoff_t index = (start + len) / PAGE_SIZE;
bool stop = true;
unsigned int i;
XA_STATE(xas, &mapping->i_pages, index);
pagevec_init(&pvec);
do {
/* Firstly, we gather up a batch of contiguous dirty pages
* under the RCU read lock - but we can't clear the dirty flags
* there if any of those pages are mapped.
*/
rcu_read_lock();
xas_for_each(&xas, page, ULONG_MAX) {
stop = true;
if (xas_retry(&xas, page))
continue;
if (xa_is_value(page))
break;
if (page->index != index)
break;
if (!page_cache_get_speculative(page)) {
xas_reset(&xas);
continue;
}
/* Has the page moved or been split? */
if (unlikely(page != xas_reload(&xas)))
break;
if (!trylock_page(page))
break;
if (!PageDirty(page) || PageWriteback(page)) {
unlock_page(page);
break;
}
psize = thp_size(page);
priv = page_private(page);
f = afs_page_dirty_from(page, priv);
t = afs_page_dirty_to(page, priv);
if (f != 0 && !new_content) {
unlock_page(page);
break;
}
len += filler + t;
filler = psize - t;
if (len >= max_len || *_count <= 0)
stop = true;
else if (t == psize || new_content)
stop = false;
index += thp_nr_pages(page);
if (!pagevec_add(&pvec, page))
break;
if (stop)
break;
}
if (!stop)
xas_pause(&xas);
rcu_read_unlock();
/* Now, if we obtained any pages, we can shift them to being
* writable and mark them for caching.
*/
if (!pagevec_count(&pvec))
break;
for (i = 0; i < pagevec_count(&pvec); i++) {
page = pvec.pages[i];
trace_afs_page_dirty(vnode, tracepoint_string("store+"), page);
if (!clear_page_dirty_for_io(page))
BUG();
if (test_set_page_writeback(page))
BUG();
*_count -= thp_nr_pages(page);
unlock_page(page);
}
pagevec_release(&pvec);
cond_resched();
} while (!stop);
*_len = len;
}
/*
* Synchronously write back the locked page and any subsequent non-locked dirty
* pages.
*/
static ssize_t afs_write_back_from_locked_page(struct address_space *mapping,
struct writeback_control *wbc,
struct page *page,
loff_t start, loff_t end)
{
struct afs_vnode *vnode = AFS_FS_I(mapping->host);
struct iov_iter iter;
unsigned long priv;
unsigned int offset, to, len, max_len;
loff_t i_size = i_size_read(&vnode->vfs_inode);
bool new_content = test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
long count = wbc->nr_to_write;
int ret;
_enter(",%lx,%llx-%llx", page->index, start, end);
if (test_set_page_writeback(page))
BUG();
count -= thp_nr_pages(page);
/* Find all consecutive lockable dirty pages that have contiguous
* written regions, stopping when we find a page that is not
* immediately lockable, is not dirty or is missing, or we reach the
* end of the range.
*/
priv = page_private(page);
offset = afs_page_dirty_from(page, priv);
to = afs_page_dirty_to(page, priv);
trace_afs_page_dirty(vnode, tracepoint_string("store"), page);
len = to - offset;
start += offset;
if (start < i_size) {
/* Trim the write to the EOF; the extra data is ignored. Also
* put an upper limit on the size of a single storedata op.
*/
max_len = 65536 * 4096;
max_len = min_t(unsigned long long, max_len, end - start + 1);
max_len = min_t(unsigned long long, max_len, i_size - start);
if (len < max_len &&
(to == thp_size(page) || new_content))
afs_extend_writeback(mapping, vnode, &count,
start, max_len, new_content, &len);
len = min_t(loff_t, len, max_len);
}
/* We now have a contiguous set of dirty pages, each with writeback
* set; the first page is still locked at this point, but all the rest
* have been unlocked.
*/
unlock_page(page);
if (start < i_size) {
_debug("write back %x @%llx [%llx]", len, start, i_size);
iov_iter_xarray(&iter, WRITE, &mapping->i_pages, start, len);
ret = afs_store_data(vnode, &iter, start, false);
} else {
_debug("write discard %x @%llx [%llx]", len, start, i_size);
/* The dirty region was entirely beyond the EOF. */
afs_pages_written_back(vnode, start, len);
ret = 0;
}
switch (ret) {
case 0:
wbc->nr_to_write = count;
ret = len;
break;
default:
pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret);
fallthrough;
case -EACCES:
case -EPERM:
case -ENOKEY:
case -EKEYEXPIRED:
case -EKEYREJECTED:
case -EKEYREVOKED:
afs_redirty_pages(wbc, mapping, start, len);
mapping_set_error(mapping, ret);
break;
case -EDQUOT:
case -ENOSPC:
afs_redirty_pages(wbc, mapping, start, len);
mapping_set_error(mapping, -ENOSPC);
break;
case -EROFS:
case -EIO:
case -EREMOTEIO:
case -EFBIG:
case -ENOENT:
case -ENOMEDIUM:
case -ENXIO:
trace_afs_file_error(vnode, ret, afs_file_error_writeback_fail);
afs_kill_pages(mapping, start, len);
mapping_set_error(mapping, ret);
break;
}
_leave(" = %d", ret);
return ret;
}
/*
* write a page back to the server
* - the caller locked the page for us
*/
int afs_writepage(struct page *page, struct writeback_control *wbc)
{
ssize_t ret;
loff_t start;
_enter("{%lx},", page->index);
start = page->index * PAGE_SIZE;
ret = afs_write_back_from_locked_page(page->mapping, wbc, page,
start, LLONG_MAX - start);
if (ret < 0) {
_leave(" = %zd", ret);
return ret;
}
_leave(" = 0");
return 0;
}
/*
* write a region of pages back to the server
*/
static int afs_writepages_region(struct address_space *mapping,
struct writeback_control *wbc,
loff_t start, loff_t end, loff_t *_next)
{
struct page *page;
ssize_t ret;
int n;
_enter("%llx,%llx,", start, end);
do {
pgoff_t index = start / PAGE_SIZE;
n = find_get_pages_range_tag(mapping, &index, end / PAGE_SIZE,
PAGECACHE_TAG_DIRTY, 1, &page);
if (!n)
break;
start = (loff_t)page->index * PAGE_SIZE; /* May regress with THPs */
_debug("wback %lx", page->index);
/* At this point we hold neither the i_pages lock nor the
* page lock: the page may be truncated or invalidated
* (changing page->mapping to NULL), or even swizzled
* back from swapper_space to tmpfs file mapping
*/
if (wbc->sync_mode != WB_SYNC_NONE) {
ret = lock_page_killable(page);
if (ret < 0) {
put_page(page);
return ret;
}
} else {
if (!trylock_page(page)) {
put_page(page);
return 0;
}
}
if (page->mapping != mapping || !PageDirty(page)) {
start += thp_size(page);
unlock_page(page);
put_page(page);
continue;
}
if (PageWriteback(page)) {
unlock_page(page);
if (wbc->sync_mode != WB_SYNC_NONE)
wait_on_page_writeback(page);
put_page(page);
continue;
}
if (!clear_page_dirty_for_io(page))
BUG();
ret = afs_write_back_from_locked_page(mapping, wbc, page, start, end);
put_page(page);
if (ret < 0) {
_leave(" = %zd", ret);
return ret;
}
start += ret * PAGE_SIZE;
cond_resched();
} while (wbc->nr_to_write > 0);
*_next = start;
_leave(" = 0 [%llx]", *_next);
return 0;
}
/*
* write some of the pending data back to the server
*/
int afs_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct afs_vnode *vnode = AFS_FS_I(mapping->host);
loff_t start, next;
int ret;
_enter("");
/* We have to be careful as we can end up racing with setattr()
* truncating the pagecache since the caller doesn't take a lock here
* to prevent it.
*/
if (wbc->sync_mode == WB_SYNC_ALL)
down_read(&vnode->validate_lock);
else if (!down_read_trylock(&vnode->validate_lock))
return 0;
if (wbc->range_cyclic) {
start = mapping->writeback_index * PAGE_SIZE;
ret = afs_writepages_region(mapping, wbc, start, LLONG_MAX, &next);
if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
ret = afs_writepages_region(mapping, wbc, 0, start,
&next);
mapping->writeback_index = next / PAGE_SIZE;
} else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
ret = afs_writepages_region(mapping, wbc, 0, LLONG_MAX, &next);
if (wbc->nr_to_write > 0)
mapping->writeback_index = next;
} else {
ret = afs_writepages_region(mapping, wbc,
wbc->range_start, wbc->range_end, &next);
}
up_read(&vnode->validate_lock);
_leave(" = %d", ret);
return ret;
}
/*
* write to an AFS file
*/
ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from)
{
struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
ssize_t result;
size_t count = iov_iter_count(from);
_enter("{%llx:%llu},{%zu},",
vnode->fid.vid, vnode->fid.vnode, count);
if (IS_SWAPFILE(&vnode->vfs_inode)) {
printk(KERN_INFO
"AFS: Attempt to write to active swap file!\n");
return -EBUSY;
}
if (!count)
return 0;
result = generic_file_write_iter(iocb, from);
_leave(" = %zd", result);
return result;
}
/*
* flush any dirty pages for this process, and check for write errors.
* - the return status from this call provides a reliable indication of
* whether any write errors occurred for this process.
*/
int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
struct inode *inode = file_inode(file);
struct afs_vnode *vnode = AFS_FS_I(inode);
_enter("{%llx:%llu},{n=%pD},%d",
vnode->fid.vid, vnode->fid.vnode, file,
datasync);
return file_write_and_wait_range(file, start, end);
}
/*
* notification that a previously read-only page is about to become writable
* - if it returns an error, the caller will deliver a bus error signal
*/
vm_fault_t afs_page_mkwrite(struct vm_fault *vmf)
{
struct page *page = thp_head(vmf->page);
struct file *file = vmf->vma->vm_file;
struct inode *inode = file_inode(file);
struct afs_vnode *vnode = AFS_FS_I(inode);
unsigned long priv;
_enter("{{%llx:%llu}},{%lx}", vnode->fid.vid, vnode->fid.vnode, page->index);
sb_start_pagefault(inode->i_sb);
/* Wait for the page to be written to the cache before we allow it to
* be modified. We then assume the entire page will need writing back.
*/
#ifdef CONFIG_AFS_FSCACHE
if (PageFsCache(page) &&
wait_on_page_fscache_killable(page) < 0)
return VM_FAULT_RETRY;
#endif
if (wait_on_page_writeback_killable(page))
return VM_FAULT_RETRY;
if (lock_page_killable(page) < 0)
return VM_FAULT_RETRY;
/* We mustn't change page->private until writeback is complete as that
* details the portion of the page we need to write back and we might
* need to redirty the page if there's a problem.
*/
if (wait_on_page_writeback_killable(page) < 0) {
unlock_page(page);
return VM_FAULT_RETRY;
}
priv = afs_page_dirty(page, 0, thp_size(page));
priv = afs_page_dirty_mmapped(priv);
if (PagePrivate(page)) {
set_page_private(page, priv);
trace_afs_page_dirty(vnode, tracepoint_string("mkwrite+"), page);
} else {
attach_page_private(page, (void *)priv);
trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"), page);
}
file_update_time(file);
sb_end_pagefault(inode->i_sb);
return VM_FAULT_LOCKED;
}
/*
* Prune the keys cached for writeback. The caller must hold vnode->wb_lock.
*/
void afs_prune_wb_keys(struct afs_vnode *vnode)
{
LIST_HEAD(graveyard);
struct afs_wb_key *wbk, *tmp;
/* Discard unused keys */
spin_lock(&vnode->wb_lock);
if (!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_WRITEBACK) &&
!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_DIRTY)) {
list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) {
if (refcount_read(&wbk->usage) == 1)
list_move(&wbk->vnode_link, &graveyard);
}
}
spin_unlock(&vnode->wb_lock);
while (!list_empty(&graveyard)) {
wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link);
list_del(&wbk->vnode_link);
afs_put_wb_key(wbk);
}
}
/*
* Clean up a page during invalidation.
*/
int afs_launder_page(struct page *page)
{
struct address_space *mapping = page->mapping;
struct afs_vnode *vnode = AFS_FS_I(mapping->host);
struct iov_iter iter;
struct bio_vec bv[1];
unsigned long priv;
unsigned int f, t;
int ret = 0;
_enter("{%lx}", page->index);
priv = page_private(page);
if (clear_page_dirty_for_io(page)) {
f = 0;
t = thp_size(page);
if (PagePrivate(page)) {
f = afs_page_dirty_from(page, priv);
t = afs_page_dirty_to(page, priv);
}
bv[0].bv_page = page;
bv[0].bv_offset = f;
bv[0].bv_len = t - f;
iov_iter_bvec(&iter, WRITE, bv, 1, bv[0].bv_len);
trace_afs_page_dirty(vnode, tracepoint_string("launder"), page);
ret = afs_store_data(vnode, &iter, (loff_t)page->index * PAGE_SIZE,
true);
}
trace_afs_page_dirty(vnode, tracepoint_string("laundered"), page);
detach_page_private(page);
wait_on_page_fscache(page);
return ret;
}