linux/fs/afs/write.c
Linus Torvalds e81fb4198e netfs: Further cleanups after struct netfs_inode wrapper introduced
Change the signature of netfs helper functions to take a struct netfs_inode
pointer rather than a struct inode pointer where appropriate, thereby
relieving the need for the network filesystem to convert its internal inode
format down to the VFS inode only for netfslib to bounce it back up.  For
type safety, it's better not to do that (and it's less typing too).

Give netfs_write_begin() an extra argument to pass in a pointer to the
netfs_inode struct rather than deriving it internally from the file
pointer.  Note that the ->write_begin() and ->write_end() ops are intended
to be replaced in the future by netfslib code that manages this without the
need to call in twice for each page.

netfs_readpage() and similar are intended to be pointed at directly by the
address_space_operations table, so must stick to the signature dictated by
the function pointers there.

Changes
=======
- Updated the kerneldoc comments and documentation [DH].

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/CAHk-=wgkwKyNmNdKpQkqZ6DnmUL-x9hp0YBnUGjaPFEAdxDTbw@mail.gmail.com/
2022-06-10 20:55:21 +01:00

1039 lines
25 KiB
C

// 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 "internal.h"
static void afs_write_to_cache(struct afs_vnode *vnode, loff_t start, size_t len,
loff_t i_size, bool caching);
#ifdef CONFIG_AFS_FSCACHE
/*
* Mark a page as having been made dirty and thus needing writeback. We also
* need to pin the cache object to write back to.
*/
bool afs_dirty_folio(struct address_space *mapping, struct folio *folio)
{
return fscache_dirty_folio(mapping, folio,
afs_vnode_cache(AFS_FS_I(mapping->host)));
}
static void afs_folio_start_fscache(bool caching, struct folio *folio)
{
if (caching)
folio_start_fscache(folio);
}
#else
static void afs_folio_start_fscache(bool caching, struct folio *folio)
{
}
#endif
/*
* 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,
struct page **_page, void **fsdata)
{
struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
struct folio *folio;
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(&vnode->netfs, file, mapping, pos, len, &folio, fsdata);
if (ret < 0)
return ret;
index = folio_index(folio);
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 (folio_test_private(folio)) {
priv = (unsigned long)folio_get_private(folio);
f = afs_folio_dirty_from(folio, priv);
t = afs_folio_dirty_to(folio, priv);
ASSERTCMP(f, <=, t);
if (folio_test_writeback(folio)) {
trace_afs_folio_dirty(vnode, tracepoint_string("alrdy"), folio);
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 = &folio->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 = folio_write_one(folio);
if (ret < 0)
goto error;
ret = folio_lock_killable(folio);
if (ret < 0)
goto error;
goto try_again;
error:
folio_put(folio);
_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 *subpage, void *fsdata)
{
struct folio *folio = page_folio(subpage);
struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
unsigned long priv;
unsigned int f, from = offset_in_folio(folio, pos);
unsigned int t, to = from + copied;
loff_t i_size, write_end_pos;
_enter("{%llx:%llu},{%lx}",
vnode->fid.vid, vnode->fid.vnode, folio_index(folio));
if (!folio_test_uptodate(folio)) {
if (copied < len) {
copied = 0;
goto out;
}
folio_mark_uptodate(folio);
}
if (copied == 0)
goto out;
write_end_pos = pos + copied;
i_size = i_size_read(&vnode->netfs.inode);
if (write_end_pos > i_size) {
write_seqlock(&vnode->cb_lock);
i_size = i_size_read(&vnode->netfs.inode);
if (write_end_pos > i_size)
afs_set_i_size(vnode, write_end_pos);
write_sequnlock(&vnode->cb_lock);
fscache_update_cookie(afs_vnode_cache(vnode), NULL, &write_end_pos);
}
if (folio_test_private(folio)) {
priv = (unsigned long)folio_get_private(folio);
f = afs_folio_dirty_from(folio, priv);
t = afs_folio_dirty_to(folio, priv);
if (from < f)
f = from;
if (to > t)
t = to;
priv = afs_folio_dirty(folio, f, t);
folio_change_private(folio, (void *)priv);
trace_afs_folio_dirty(vnode, tracepoint_string("dirty+"), folio);
} else {
priv = afs_folio_dirty(folio, from, to);
folio_attach_private(folio, (void *)priv);
trace_afs_folio_dirty(vnode, tracepoint_string("dirty"), folio);
}
if (folio_mark_dirty(folio))
_debug("dirtied %lx", folio_index(folio));
out:
folio_unlock(folio);
folio_put(folio);
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 folio *folio;
pgoff_t index = start / PAGE_SIZE;
pgoff_t last = (start + len - 1) / PAGE_SIZE, next;
_enter("{%llx:%llu},%llx @%llx",
vnode->fid.vid, vnode->fid.vnode, len, start);
do {
_debug("kill %lx (to %lx)", index, last);
folio = filemap_get_folio(mapping, index);
if (!folio) {
next = index + 1;
continue;
}
next = folio_next_index(folio);
folio_clear_uptodate(folio);
folio_end_writeback(folio);
folio_lock(folio);
generic_error_remove_page(mapping, &folio->page);
folio_unlock(folio);
folio_put(folio);
} while (index = next, index <= last);
_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 folio *folio;
pgoff_t index = start / PAGE_SIZE;
pgoff_t last = (start + len - 1) / PAGE_SIZE, next;
_enter("{%llx:%llu},%llx @%llx",
vnode->fid.vid, vnode->fid.vnode, len, start);
do {
_debug("redirty %llx @%llx", len, start);
folio = filemap_get_folio(mapping, index);
if (!folio) {
next = index + 1;
continue;
}
next = index + folio_nr_pages(folio);
folio_redirty_for_writepage(wbc, folio);
folio_end_writeback(folio);
folio_put(folio);
} while (index = next, index <= last);
_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->netfs.inode.i_mapping;
struct folio *folio;
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, folio, end) {
if (!folio_test_writeback(folio)) {
kdebug("bad %x @%llx page %lx %lx",
len, start, folio_index(folio), end);
ASSERT(folio_test_writeback(folio));
}
trace_afs_folio_dirty(vnode, tracepoint_string("clear"), folio);
folio_detach_private(folio);
folio_end_writeback(folio);
}
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);
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;
}
afs_op_set_vnode(op, 0, vnode);
op->file[0].dv_delta = 1;
op->file[0].modification = true;
op->store.write_iter = iter;
op->store.pos = pos;
op->store.size = size;
op->store.i_size = max(pos + size, vnode->netfs.remote_i_size);
op->store.laundering = laundering;
op->mtime = vnode->netfs.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,
bool caching,
unsigned int *_len)
{
struct pagevec pvec;
struct folio *folio;
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, folio, ULONG_MAX) {
stop = true;
if (xas_retry(&xas, folio))
continue;
if (xa_is_value(folio))
break;
if (folio_index(folio) != index)
break;
if (!folio_try_get_rcu(folio)) {
xas_reset(&xas);
continue;
}
/* Has the page moved or been split? */
if (unlikely(folio != xas_reload(&xas))) {
folio_put(folio);
break;
}
if (!folio_trylock(folio)) {
folio_put(folio);
break;
}
if (!folio_test_dirty(folio) ||
folio_test_writeback(folio) ||
folio_test_fscache(folio)) {
folio_unlock(folio);
folio_put(folio);
break;
}
psize = folio_size(folio);
priv = (unsigned long)folio_get_private(folio);
f = afs_folio_dirty_from(folio, priv);
t = afs_folio_dirty_to(folio, priv);
if (f != 0 && !new_content) {
folio_unlock(folio);
folio_put(folio);
break;
}
len += filler + t;
filler = psize - t;
if (len >= max_len || *_count <= 0)
stop = true;
else if (t == psize || new_content)
stop = false;
index += folio_nr_pages(folio);
if (!pagevec_add(&pvec, &folio->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++) {
folio = page_folio(pvec.pages[i]);
trace_afs_folio_dirty(vnode, tracepoint_string("store+"), folio);
if (!folio_clear_dirty_for_io(folio))
BUG();
if (folio_start_writeback(folio))
BUG();
afs_folio_start_fscache(caching, folio);
*_count -= folio_nr_pages(folio);
folio_unlock(folio);
}
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_folio(struct address_space *mapping,
struct writeback_control *wbc,
struct folio *folio,
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->netfs.inode);
bool new_content = test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
bool caching = fscache_cookie_enabled(afs_vnode_cache(vnode));
long count = wbc->nr_to_write;
int ret;
_enter(",%lx,%llx-%llx", folio_index(folio), start, end);
if (folio_start_writeback(folio))
BUG();
afs_folio_start_fscache(caching, folio);
count -= folio_nr_pages(folio);
/* 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 = (unsigned long)folio_get_private(folio);
offset = afs_folio_dirty_from(folio, priv);
to = afs_folio_dirty_to(folio, priv);
trace_afs_folio_dirty(vnode, tracepoint_string("store"), folio);
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 == folio_size(folio) || new_content))
afs_extend_writeback(mapping, vnode, &count,
start, max_len, new_content,
caching, &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.
*/
folio_unlock(folio);
if (start < i_size) {
_debug("write back %x @%llx [%llx]", len, start, i_size);
/* Speculatively write to the cache. We have to fix this up
* later if the store fails.
*/
afs_write_to_cache(vnode, start, len, i_size, caching);
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. */
fscache_clear_page_bits(mapping, start, len, caching);
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:
case -ENETRESET:
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 *subpage, struct writeback_control *wbc)
{
struct folio *folio = page_folio(subpage);
ssize_t ret;
loff_t start;
_enter("{%lx},", folio_index(folio));
#ifdef CONFIG_AFS_FSCACHE
folio_wait_fscache(folio);
#endif
start = folio_index(folio) * PAGE_SIZE;
ret = afs_write_back_from_locked_folio(folio_mapping(folio), wbc,
folio, 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 folio *folio;
struct page *head_page;
ssize_t ret;
int n, skips = 0;
_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, &head_page);
if (!n)
break;
folio = page_folio(head_page);
start = folio_pos(folio); /* May regress with THPs */
_debug("wback %lx", folio_index(folio));
/* 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 = folio_lock_killable(folio);
if (ret < 0) {
folio_put(folio);
return ret;
}
} else {
if (!folio_trylock(folio)) {
folio_put(folio);
return 0;
}
}
if (folio_mapping(folio) != mapping ||
!folio_test_dirty(folio)) {
start += folio_size(folio);
folio_unlock(folio);
folio_put(folio);
continue;
}
if (folio_test_writeback(folio) ||
folio_test_fscache(folio)) {
folio_unlock(folio);
if (wbc->sync_mode != WB_SYNC_NONE) {
folio_wait_writeback(folio);
#ifdef CONFIG_AFS_FSCACHE
folio_wait_fscache(folio);
#endif
} else {
start += folio_size(folio);
}
folio_put(folio);
if (wbc->sync_mode == WB_SYNC_NONE) {
if (skips >= 5 || need_resched())
break;
skips++;
}
continue;
}
if (!folio_clear_dirty_for_io(folio))
BUG();
ret = afs_write_back_from_locked_folio(mapping, wbc, folio, start, end);
folio_put(folio);
if (ret < 0) {
_leave(" = %zd", ret);
return ret;
}
start += ret;
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 (ret == 0) {
mapping->writeback_index = next / PAGE_SIZE;
if (start > 0 && wbc->nr_to_write > 0) {
ret = afs_writepages_region(mapping, wbc, 0,
start, &next);
if (ret == 0)
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 && ret == 0)
mapping->writeback_index = next / PAGE_SIZE;
} 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));
struct afs_file *af = iocb->ki_filp->private_data;
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->netfs.inode)) {
printk(KERN_INFO
"AFS: Attempt to write to active swap file!\n");
return -EBUSY;
}
if (!count)
return 0;
result = afs_validate(vnode, af->key);
if (result < 0)
return result;
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 afs_vnode *vnode = AFS_FS_I(file_inode(file));
struct afs_file *af = file->private_data;
int ret;
_enter("{%llx:%llu},{n=%pD},%d",
vnode->fid.vid, vnode->fid.vnode, file,
datasync);
ret = afs_validate(vnode, af->key);
if (ret < 0)
return ret;
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 folio *folio = page_folio(vmf->page);
struct file *file = vmf->vma->vm_file;
struct inode *inode = file_inode(file);
struct afs_vnode *vnode = AFS_FS_I(inode);
struct afs_file *af = file->private_data;
unsigned long priv;
vm_fault_t ret = VM_FAULT_RETRY;
_enter("{{%llx:%llu}},{%lx}", vnode->fid.vid, vnode->fid.vnode, folio_index(folio));
afs_validate(vnode, af->key);
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 (folio_test_fscache(folio) &&
folio_wait_fscache_killable(folio) < 0)
goto out;
#endif
if (folio_wait_writeback_killable(folio))
goto out;
if (folio_lock_killable(folio) < 0)
goto out;
/* We mustn't change folio->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 (folio_wait_writeback_killable(folio) < 0) {
folio_unlock(folio);
goto out;
}
priv = afs_folio_dirty(folio, 0, folio_size(folio));
priv = afs_folio_dirty_mmapped(priv);
if (folio_test_private(folio)) {
folio_change_private(folio, (void *)priv);
trace_afs_folio_dirty(vnode, tracepoint_string("mkwrite+"), folio);
} else {
folio_attach_private(folio, (void *)priv);
trace_afs_folio_dirty(vnode, tracepoint_string("mkwrite"), folio);
}
file_update_time(file);
ret = VM_FAULT_LOCKED;
out:
sb_end_pagefault(inode->i_sb);
return ret;
}
/*
* 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->netfs.inode.i_data, PAGECACHE_TAG_WRITEBACK) &&
!mapping_tagged(&vnode->netfs.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_folio(struct folio *folio)
{
struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
struct iov_iter iter;
struct bio_vec bv[1];
unsigned long priv;
unsigned int f, t;
int ret = 0;
_enter("{%lx}", folio->index);
priv = (unsigned long)folio_get_private(folio);
if (folio_clear_dirty_for_io(folio)) {
f = 0;
t = folio_size(folio);
if (folio_test_private(folio)) {
f = afs_folio_dirty_from(folio, priv);
t = afs_folio_dirty_to(folio, priv);
}
bv[0].bv_page = &folio->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_folio_dirty(vnode, tracepoint_string("launder"), folio);
ret = afs_store_data(vnode, &iter, folio_pos(folio) + f, true);
}
trace_afs_folio_dirty(vnode, tracepoint_string("laundered"), folio);
folio_detach_private(folio);
folio_wait_fscache(folio);
return ret;
}
/*
* Deal with the completion of writing the data to the cache.
*/
static void afs_write_to_cache_done(void *priv, ssize_t transferred_or_error,
bool was_async)
{
struct afs_vnode *vnode = priv;
if (IS_ERR_VALUE(transferred_or_error) &&
transferred_or_error != -ENOBUFS)
afs_invalidate_cache(vnode, 0);
}
/*
* Save the write to the cache also.
*/
static void afs_write_to_cache(struct afs_vnode *vnode,
loff_t start, size_t len, loff_t i_size,
bool caching)
{
fscache_write_to_cache(afs_vnode_cache(vnode),
vnode->netfs.inode.i_mapping, start, len, i_size,
afs_write_to_cache_done, vnode, caching);
}