linux/fs/afs/write.c
Linus Torvalds 0c59ae1290 AFS fileserver rotation fix
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Merge tag 'afs-fix-rotation-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull afs updates from David Howells:
 "The majority of the patches are aimed at fixing and improving the AFS
  filesystem's rotation over server IP addresses, but there are also
  some fixes from Oleg Nesterov for the use of read_seqbegin_or_lock().

   - Fix fileserver probe handling so that the next round of probes
     doesn't break ongoing server/address rotation by clearing all the
     probe result tracking. This could occasionally cause the rotation
     algorithm to drop straight through, give a 'successful' result
     without actually emitting any RPC calls, leaving the reply buffer
     in an undefined state.

     Instead, detach the probe results into a separate struct and
     allocate a new one each time we start probing and update the
     pointer to it. Probes are also sent in order of address preference
     to try and improve the chance that the preferred one will complete
     first.

   - Fix server rotation so that it uses configurable address
     preferences across on the probes that have completed so far than
     ranking them by RTT as the latter doesn't necessarily give the best
     route. The preference list can be altered by writing into
     /proc/net/afs/addr_prefs.

   - Fix the handling of Read-Only (and Backup) volume callbacks as
     there is one per volume, not one per file, so if someone performs a
     command that, say, offlines the volume but doesn't change it, when
     it comes back online we don't spam the server with a status fetch
     for every vnode we're using. Instead, check the Creation timestamp
     in the VolSync record when prompted by a callback break.

   - Handle volume regression (ie. a RW volume being restored from a
     backup) by scrubbing all cache data for that volume. This is
     detected from the VolSync creation timestamp.

   - Adjust abort handling and abort -> error mapping to match better
     with what other AFS clients do.

   - Fix offline and busy volume state handling as they only apply to
     individual server instances and not entire volumes and the rotation
     algorithm should go and look at other servers if available. Also
     make it sleep briefly before each retry if all the volume instances
     are unavailable"

* tag 'afs-fix-rotation-20240105' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (40 commits)
  afs: trace: Log afs_make_call(), including server address
  afs: Fix offline and busy message emission
  afs: Fix fileserver rotation
  afs: Overhaul invalidation handling to better support RO volumes
  afs: Parse the VolSync record in the reply of a number of RPC ops
  afs: Don't leave DONTUSE/NEWREPSITE servers out of server list
  afs: Fix comment in afs_do_lookup()
  afs: Apply server breaks to mmap'd files in the call processor
  afs: Move the vnode/volume validity checking code into its own file
  afs: Defer volume record destruction to a workqueue
  afs: Make it possible to find the volumes that are using a server
  afs: Combine the endpoint state bools into a bitmask
  afs: Keep a record of the current fileserver endpoint state
  afs: Dispatch vlserver probes in priority order
  afs: Dispatch fileserver probes in priority order
  afs: Mark address lists with configured priorities
  afs: Provide a way to configure address priorities
  afs: Remove the unimplemented afs_cmp_addr_list()
  afs: Add some more info to /proc/net/afs/servers
  rxrpc: Create a procfile to display outstanding client conn bundles
  ...
2024-01-10 10:11:01 -08:00

1053 lines
26 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 int afs_writepages_region(struct address_space *mapping,
struct writeback_control *wbc,
loff_t start, loff_t end, loff_t *_next,
bool max_one_loop);
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
/*
* Flush out a conflicting write. This may extend the write to the surrounding
* pages if also dirty and contiguous to the conflicting region..
*/
static int afs_flush_conflicting_write(struct address_space *mapping,
struct folio *folio)
{
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
.nr_to_write = LONG_MAX,
.range_start = folio_pos(folio),
.range_end = LLONG_MAX,
};
loff_t next;
return afs_writepages_region(mapping, &wbc, folio_pos(folio), LLONG_MAX,
&next, true);
}
/*
* 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);
folio_unlock(folio);
goto wait_for_writeback;
}
/* 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_file_page(folio, pos / PAGE_SIZE);
_leave(" = 0");
return 0;
/* The previous write and this write aren't adjacent or overlapping, so
* flush the page out.
*/
flush_conflicting_write:
trace_afs_folio_dirty(vnode, tracepoint_string("confl"), folio);
folio_unlock(folio);
ret = afs_flush_conflicting_write(mapping, folio);
if (ret < 0)
goto error;
wait_for_writeback:
ret = folio_wait_writeback_killable(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 (IS_ERR(folio)) {
next = index + 1;
continue;
}
next = folio_next_index(folio);
folio_clear_uptodate(folio);
folio_end_writeback(folio);
folio_lock(folio);
generic_error_remove_folio(mapping, folio);
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 (IS_ERR(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 (!afs_op_error(op)) {
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.pos = pos;
op->store.size = size;
op->store.laundering = laundering;
op->flags |= AFS_OPERATION_UNINTR;
op->ops = &afs_store_data_operation;
try_next_key:
afs_begin_vnode_operation(op);
op->store.write_iter = iter;
op->store.i_size = max(pos + size, vnode->netfs.remote_i_size);
op->mtime = inode_get_mtime(&vnode->netfs.inode);
afs_wait_for_operation(op);
switch (afs_op_error(op)) {
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", afs_op_error(op));
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 folio_batch fbatch;
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);
folio_batch_init(&fbatch);
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 (!folio_batch_add(&fbatch, folio))
break;
if (stop)
break;
}
if (!stop)
xas_pause(&xas);
rcu_read_unlock();
/* Now, if we obtained any folios, we can shift them to being
* writable and mark them for caching.
*/
if (!folio_batch_count(&fbatch))
break;
for (i = 0; i < folio_batch_count(&fbatch); i++) {
folio = fbatch.folios[i];
trace_afs_folio_dirty(vnode, tracepoint_string("store+"), folio);
if (!folio_clear_dirty_for_io(folio))
BUG();
folio_start_writeback(folio);
afs_folio_start_fscache(caching, folio);
*_count -= folio_nr_pages(folio);
folio_unlock(folio);
}
folio_batch_release(&fbatch);
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);
folio_start_writeback(folio);
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, ITER_SOURCE, &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 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,
bool max_one_loop)
{
struct folio *folio;
struct folio_batch fbatch;
ssize_t ret;
unsigned int i;
int n, skips = 0;
_enter("%llx,%llx,", start, end);
folio_batch_init(&fbatch);
do {
pgoff_t index = start / PAGE_SIZE;
n = filemap_get_folios_tag(mapping, &index, end / PAGE_SIZE,
PAGECACHE_TAG_DIRTY, &fbatch);
if (!n)
break;
for (i = 0; i < n; i++) {
folio = fbatch.folios[i];
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
*/
try_again:
if (wbc->sync_mode != WB_SYNC_NONE) {
ret = folio_lock_killable(folio);
if (ret < 0) {
folio_batch_release(&fbatch);
return ret;
}
} else {
if (!folio_trylock(folio))
continue;
}
if (folio->mapping != mapping ||
!folio_test_dirty(folio)) {
start += folio_size(folio);
folio_unlock(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
goto try_again;
}
start += folio_size(folio);
if (wbc->sync_mode == WB_SYNC_NONE) {
if (skips >= 5 || need_resched()) {
*_next = start;
folio_batch_release(&fbatch);
_leave(" = 0 [%llx]", *_next);
return 0;
}
skips++;
}
continue;
}
if (!folio_clear_dirty_for_io(folio))
BUG();
ret = afs_write_back_from_locked_folio(mapping, wbc,
folio, start, end);
if (ret < 0) {
_leave(" = %zd", ret);
folio_batch_release(&fbatch);
return ret;
}
start += ret;
}
folio_batch_release(&fbatch);
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, false);
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, false);
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, false);
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, false);
}
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;
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);
}
bvec_set_folio(&bv, folio, t - f, f);
iov_iter_bvec(&iter, ITER_SOURCE, &bv, 1, bv.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);
}