// 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 "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);
|
}
|
|
/*
|
* partly or wholly fill a page that's under preparation for writing
|
*/
|
static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
|
loff_t pos, unsigned int len, struct page *page)
|
{
|
struct afs_read *req;
|
size_t p;
|
void *data;
|
int ret;
|
|
_enter(",,%llu", (unsigned long long)pos);
|
|
if (pos >= vnode->vfs_inode.i_size) {
|
p = pos & ~PAGE_MASK;
|
ASSERTCMP(p + len, <=, PAGE_SIZE);
|
data = kmap(page);
|
memset(data + p, 0, len);
|
kunmap(page);
|
return 0;
|
}
|
|
req = kzalloc(struct_size(req, array, 1), GFP_KERNEL);
|
if (!req)
|
return -ENOMEM;
|
|
refcount_set(&req->usage, 1);
|
req->pos = pos;
|
req->len = len;
|
req->nr_pages = 1;
|
req->pages = req->array;
|
req->pages[0] = page;
|
get_page(page);
|
|
ret = afs_fetch_data(vnode, key, req);
|
afs_put_read(req);
|
if (ret < 0) {
|
if (ret == -ENOENT) {
|
_debug("got NOENT from server"
|
" - marking file deleted and stale");
|
set_bit(AFS_VNODE_DELETED, &vnode->flags);
|
ret = -ESTALE;
|
}
|
}
|
|
_leave(" = %d", ret);
|
return ret;
|
}
|
|
/*
|
* 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;
|
struct key *key = afs_file_key(file);
|
unsigned long priv;
|
unsigned f, from = pos & (PAGE_SIZE - 1);
|
unsigned t, to = from + len;
|
pgoff_t index = pos >> PAGE_SHIFT;
|
int ret;
|
|
_enter("{%llx:%llu},{%lx},%u,%u",
|
vnode->fid.vid, vnode->fid.vnode, index, from, to);
|
|
page = grab_cache_page_write_begin(mapping, index, flags);
|
if (!page)
|
return -ENOMEM;
|
|
if (!PageUptodate(page) && len != PAGE_SIZE) {
|
ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page);
|
if (ret < 0) {
|
unlock_page(page);
|
put_page(page);
|
_leave(" = %d [prep]", ret);
|
return ret;
|
}
|
SetPageUptodate(page);
|
}
|
|
try_again:
|
/* See if this page is already partially written in a way that we can
|
* merge the new write with.
|
*/
|
t = f = 0;
|
if (PagePrivate(page)) {
|
priv = page_private(page);
|
f = afs_page_dirty_from(priv);
|
t = afs_page_dirty_to(priv);
|
ASSERTCMP(f, <=, t);
|
}
|
|
if (f != t) {
|
if (PageWriteback(page)) {
|
trace_afs_page_dirty(vnode, tracepoint_string("alrdy"),
|
page->index, priv);
|
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));
|
struct key *key = afs_file_key(file);
|
unsigned long priv;
|
unsigned int f, from = pos & (PAGE_SIZE - 1);
|
unsigned int t, to = from + copied;
|
loff_t i_size, maybe_i_size;
|
int ret = 0;
|
|
_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)
|
afs_set_i_size(vnode, maybe_i_size);
|
write_sequnlock(&vnode->cb_lock);
|
}
|
|
if (!PageUptodate(page)) {
|
if (copied < len) {
|
/* Try and load any missing data from the server. The
|
* unmarshalling routine will take care of clearing any
|
* bits that are beyond the EOF.
|
*/
|
ret = afs_fill_page(vnode, key, pos + copied,
|
len - copied, page);
|
if (ret < 0)
|
goto out;
|
}
|
SetPageUptodate(page);
|
}
|
|
if (PagePrivate(page)) {
|
priv = page_private(page);
|
f = afs_page_dirty_from(priv);
|
t = afs_page_dirty_to(priv);
|
if (from < f)
|
f = from;
|
if (to > t)
|
t = to;
|
priv = afs_page_dirty(f, t);
|
set_page_private(page, priv);
|
trace_afs_page_dirty(vnode, tracepoint_string("dirty+"),
|
page->index, priv);
|
} else {
|
priv = afs_page_dirty(from, to);
|
attach_page_private(page, (void *)priv);
|
trace_afs_page_dirty(vnode, tracepoint_string("dirty"),
|
page->index, priv);
|
}
|
|
set_page_dirty(page);
|
if (PageDirty(page))
|
_debug("dirtied");
|
ret = copied;
|
|
out:
|
unlock_page(page);
|
put_page(page);
|
return ret;
|
}
|
|
/*
|
* kill all the pages in the given range
|
*/
|
static void afs_kill_pages(struct address_space *mapping,
|
pgoff_t first, pgoff_t last)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(mapping->host);
|
struct pagevec pv;
|
unsigned count, loop;
|
|
_enter("{%llx:%llu},%lx-%lx",
|
vnode->fid.vid, vnode->fid.vnode, first, last);
|
|
pagevec_init(&pv);
|
|
do {
|
_debug("kill %lx-%lx", first, last);
|
|
count = last - first + 1;
|
if (count > PAGEVEC_SIZE)
|
count = PAGEVEC_SIZE;
|
pv.nr = find_get_pages_contig(mapping, first, count, pv.pages);
|
ASSERTCMP(pv.nr, ==, count);
|
|
for (loop = 0; loop < count; loop++) {
|
struct page *page = pv.pages[loop];
|
ClearPageUptodate(page);
|
SetPageError(page);
|
end_page_writeback(page);
|
if (page->index >= first)
|
first = page->index + 1;
|
lock_page(page);
|
generic_error_remove_page(mapping, page);
|
unlock_page(page);
|
}
|
|
__pagevec_release(&pv);
|
} while (first <= last);
|
|
_leave("");
|
}
|
|
/*
|
* Redirty all the pages in a given range.
|
*/
|
static void afs_redirty_pages(struct writeback_control *wbc,
|
struct address_space *mapping,
|
pgoff_t first, pgoff_t last)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(mapping->host);
|
struct pagevec pv;
|
unsigned count, loop;
|
|
_enter("{%llx:%llu},%lx-%lx",
|
vnode->fid.vid, vnode->fid.vnode, first, last);
|
|
pagevec_init(&pv);
|
|
do {
|
_debug("redirty %lx-%lx", first, last);
|
|
count = last - first + 1;
|
if (count > PAGEVEC_SIZE)
|
count = PAGEVEC_SIZE;
|
pv.nr = find_get_pages_contig(mapping, first, count, pv.pages);
|
ASSERTCMP(pv.nr, ==, count);
|
|
for (loop = 0; loop < count; loop++) {
|
struct page *page = pv.pages[loop];
|
|
redirty_page_for_writepage(wbc, page);
|
end_page_writeback(page);
|
if (page->index >= first)
|
first = page->index + 1;
|
}
|
|
__pagevec_release(&pv);
|
} while (first <= last);
|
|
_leave("");
|
}
|
|
/*
|
* completion of write to server
|
*/
|
static void afs_pages_written_back(struct afs_vnode *vnode,
|
pgoff_t first, pgoff_t last)
|
{
|
struct pagevec pv;
|
unsigned long priv;
|
unsigned count, loop;
|
|
_enter("{%llx:%llu},{%lx-%lx}",
|
vnode->fid.vid, vnode->fid.vnode, first, last);
|
|
pagevec_init(&pv);
|
|
do {
|
_debug("done %lx-%lx", first, last);
|
|
count = last - first + 1;
|
if (count > PAGEVEC_SIZE)
|
count = PAGEVEC_SIZE;
|
pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping,
|
first, count, pv.pages);
|
ASSERTCMP(pv.nr, ==, count);
|
|
for (loop = 0; loop < count; loop++) {
|
priv = (unsigned long)detach_page_private(pv.pages[loop]);
|
trace_afs_page_dirty(vnode, tracepoint_string("clear"),
|
pv.pages[loop]->index, priv);
|
end_page_writeback(pv.pages[loop]);
|
}
|
first += count;
|
__pagevec_release(&pv);
|
} while (first <= last);
|
|
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.first, op->store.last);
|
afs_stat_v(vnode, n_stores);
|
atomic_long_add((op->store.last * PAGE_SIZE + op->store.last_to) -
|
(op->store.first * PAGE_SIZE + op->store.first_offset),
|
&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 address_space *mapping,
|
pgoff_t first, pgoff_t last,
|
unsigned offset, unsigned to, bool laundering)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(mapping->host);
|
struct afs_operation *op;
|
struct afs_wb_key *wbk = NULL;
|
int ret;
|
|
_enter("%s{%llx:%llu.%u},%lx,%lx,%x,%x",
|
vnode->volume->name,
|
vnode->fid.vid,
|
vnode->fid.vnode,
|
vnode->fid.unique,
|
first, last, offset, to);
|
|
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;
|
}
|
|
afs_op_set_vnode(op, 0, vnode);
|
op->file[0].dv_delta = 1;
|
op->store.mapping = mapping;
|
op->file[0].modification = true;
|
op->store.first = first;
|
op->store.last = last;
|
op->store.first_offset = offset;
|
op->store.last_to = to;
|
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);
|
}
|
|
/*
|
* Synchronously write back the locked page and any subsequent non-locked dirty
|
* pages.
|
*/
|
static int afs_write_back_from_locked_page(struct address_space *mapping,
|
struct writeback_control *wbc,
|
struct page *primary_page,
|
pgoff_t final_page)
|
{
|
struct afs_vnode *vnode = AFS_FS_I(mapping->host);
|
struct page *pages[8], *page;
|
unsigned long count, priv;
|
unsigned n, offset, to, f, t;
|
pgoff_t start, first, last;
|
loff_t i_size, end;
|
int loop, ret;
|
|
_enter(",%lx", primary_page->index);
|
|
count = 1;
|
if (test_set_page_writeback(primary_page))
|
BUG();
|
|
/* 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.
|
*/
|
start = primary_page->index;
|
priv = page_private(primary_page);
|
offset = afs_page_dirty_from(priv);
|
to = afs_page_dirty_to(priv);
|
trace_afs_page_dirty(vnode, tracepoint_string("store"),
|
primary_page->index, priv);
|
|
WARN_ON(offset == to);
|
if (offset == to)
|
trace_afs_page_dirty(vnode, tracepoint_string("WARN"),
|
primary_page->index, priv);
|
|
if (start >= final_page ||
|
(to < PAGE_SIZE && !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)))
|
goto no_more;
|
|
start++;
|
do {
|
_debug("more %lx [%lx]", start, count);
|
n = final_page - start + 1;
|
if (n > ARRAY_SIZE(pages))
|
n = ARRAY_SIZE(pages);
|
n = find_get_pages_contig(mapping, start, ARRAY_SIZE(pages), pages);
|
_debug("fgpc %u", n);
|
if (n == 0)
|
goto no_more;
|
if (pages[0]->index != start) {
|
do {
|
put_page(pages[--n]);
|
} while (n > 0);
|
goto no_more;
|
}
|
|
for (loop = 0; loop < n; loop++) {
|
page = pages[loop];
|
if (to != PAGE_SIZE &&
|
!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags))
|
break;
|
if (page->index > final_page)
|
break;
|
if (!trylock_page(page))
|
break;
|
if (!PageDirty(page) || PageWriteback(page)) {
|
unlock_page(page);
|
break;
|
}
|
|
priv = page_private(page);
|
f = afs_page_dirty_from(priv);
|
t = afs_page_dirty_to(priv);
|
if (f != 0 &&
|
!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) {
|
unlock_page(page);
|
break;
|
}
|
to = t;
|
|
trace_afs_page_dirty(vnode, tracepoint_string("store+"),
|
page->index, priv);
|
|
if (!clear_page_dirty_for_io(page))
|
BUG();
|
if (test_set_page_writeback(page))
|
BUG();
|
unlock_page(page);
|
put_page(page);
|
}
|
count += loop;
|
if (loop < n) {
|
for (; loop < n; loop++)
|
put_page(pages[loop]);
|
goto no_more;
|
}
|
|
start += loop;
|
} while (start <= final_page && count < 65536);
|
|
no_more:
|
/* 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(primary_page);
|
|
first = primary_page->index;
|
last = first + count - 1;
|
|
end = (loff_t)last * PAGE_SIZE + to;
|
i_size = i_size_read(&vnode->vfs_inode);
|
|
_debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to);
|
if (end > i_size)
|
to = i_size & ~PAGE_MASK;
|
|
ret = afs_store_data(mapping, first, last, offset, to, false);
|
switch (ret) {
|
case 0:
|
ret = count;
|
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, first, last);
|
mapping_set_error(mapping, ret);
|
break;
|
|
case -EDQUOT:
|
case -ENOSPC:
|
afs_redirty_pages(wbc, mapping, first, last);
|
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, first, last);
|
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)
|
{
|
int ret;
|
|
_enter("{%lx},", page->index);
|
|
ret = afs_write_back_from_locked_page(page->mapping, wbc, page,
|
wbc->range_end >> PAGE_SHIFT);
|
if (ret < 0) {
|
_leave(" = %d", ret);
|
return 0;
|
}
|
|
wbc->nr_to_write -= 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,
|
pgoff_t index, pgoff_t end, pgoff_t *_next)
|
{
|
struct page *page;
|
int ret, n;
|
|
_enter(",,%lx,%lx,", index, end);
|
|
do {
|
n = find_get_pages_range_tag(mapping, &index, end,
|
PAGECACHE_TAG_DIRTY, 1, &page);
|
if (!n)
|
break;
|
|
_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
|
*/
|
ret = lock_page_killable(page);
|
if (ret < 0) {
|
put_page(page);
|
_leave(" = %d", ret);
|
return ret;
|
}
|
|
if (page->mapping != mapping || !PageDirty(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, end);
|
put_page(page);
|
if (ret < 0) {
|
_leave(" = %d", ret);
|
return ret;
|
}
|
|
wbc->nr_to_write -= ret;
|
|
cond_resched();
|
} while (index < end && wbc->nr_to_write > 0);
|
|
*_next = index;
|
_leave(" = 0 [%lx]", *_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);
|
pgoff_t start, end, 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;
|
end = -1;
|
ret = afs_writepages_region(mapping, wbc, start, end, &next);
|
if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
|
ret = afs_writepages_region(mapping, wbc, 0, start,
|
&next);
|
mapping->writeback_index = next;
|
} else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) {
|
end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT);
|
ret = afs_writepages_region(mapping, wbc, 0, end, &next);
|
if (wbc->nr_to_write > 0)
|
mapping->writeback_index = next;
|
} else {
|
start = wbc->range_start >> PAGE_SHIFT;
|
end = wbc->range_end >> PAGE_SHIFT;
|
ret = afs_writepages_region(mapping, wbc, start, 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 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, vmf->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
|
fscache_wait_on_page_write(vnode->cache, vmf->page);
|
#endif
|
|
if (PageWriteback(vmf->page) &&
|
wait_on_page_bit_killable(vmf->page, PG_writeback) < 0)
|
return VM_FAULT_RETRY;
|
|
if (lock_page_killable(vmf->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.
|
*/
|
wait_on_page_writeback(vmf->page);
|
|
priv = afs_page_dirty(0, PAGE_SIZE);
|
priv = afs_page_dirty_mmapped(priv);
|
trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"),
|
vmf->page->index, priv);
|
if (PagePrivate(vmf->page))
|
set_page_private(vmf->page, priv);
|
else
|
attach_page_private(vmf->page, (void *)priv);
|
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);
|
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 = PAGE_SIZE;
|
if (PagePrivate(page)) {
|
f = afs_page_dirty_from(priv);
|
t = afs_page_dirty_to(priv);
|
}
|
|
trace_afs_page_dirty(vnode, tracepoint_string("launder"),
|
page->index, priv);
|
ret = afs_store_data(mapping, page->index, page->index, t, f, true);
|
}
|
|
priv = (unsigned long)detach_page_private(page);
|
trace_afs_page_dirty(vnode, tracepoint_string("laundered"),
|
page->index, priv);
|
|
#ifdef CONFIG_AFS_FSCACHE
|
if (PageFsCache(page)) {
|
fscache_wait_on_page_write(vnode->cache, page);
|
fscache_uncache_page(vnode->cache, page);
|
}
|
#endif
|
return ret;
|
}
|
