mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
switching from a user process to a kernel thread. - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav. - zsmalloc performance improvements from Sergey Senozhatsky. - Yue Zhao has found and fixed some data race issues around the alteration of memcg userspace tunables. - VFS rationalizations from Christoph Hellwig: - removal of most of the callers of write_one_page(). - make __filemap_get_folio()'s return value more useful - Luis Chamberlain has changed tmpfs so it no longer requires swap backing. Use `mount -o noswap'. - Qi Zheng has made the slab shrinkers operate locklessly, providing some scalability benefits. - Keith Busch has improved dmapool's performance, making part of its operations O(1) rather than O(n). - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd, permitting userspace to wr-protect anon memory unpopulated ptes. - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather than exclusive, and has fixed a bunch of errors which were caused by its unintuitive meaning. - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature, which causes minor faults to install a write-protected pte. - Vlastimil Babka has done some maintenance work on vma_merge(): cleanups to the kernel code and improvements to our userspace test harness. - Cleanups to do_fault_around() by Lorenzo Stoakes. - Mike Rapoport has moved a lot of initialization code out of various mm/ files and into mm/mm_init.c. - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for DRM, but DRM doesn't use it any more. - Lorenzo has also coverted read_kcore() and vread() to use iterators and has thereby removed the use of bounce buffers in some cases. - Lorenzo has also contributed further cleanups of vma_merge(). - Chaitanya Prakash provides some fixes to the mmap selftesting code. - Matthew Wilcox changes xfs and afs so they no longer take sleeping locks in ->map_page(), a step towards RCUification of pagefaults. - Suren Baghdasaryan has improved mmap_lock scalability by switching to per-VMA locking. - Frederic Weisbecker has reworked the percpu cache draining so that it no longer causes latency glitches on cpu isolated workloads. - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig logic. - Liu Shixin has changed zswap's initialization so we no longer waste a chunk of memory if zswap is not being used. - Yosry Ahmed has improved the performance of memcg statistics flushing. - David Stevens has fixed several issues involving khugepaged, userfaultfd and shmem. - Christoph Hellwig has provided some cleanup work to zram's IO-related code paths. - David Hildenbrand has fixed up some issues in the selftest code's testing of our pte state changing. - Pankaj Raghav has made page_endio() unneeded and has removed it. - Peter Xu contributed some rationalizations of the userfaultfd selftests. - Yosry Ahmed has fixed an issue around memcg's page recalim accounting. - Chaitanya Prakash has fixed some arm-related issues in the selftests/mm code. - Longlong Xia has improved the way in which KSM handles hwpoisoned pages. - Peter Xu fixes a few issues with uffd-wp at fork() time. - Stefan Roesch has changed KSM so that it may now be used on a per-process and per-cgroup basis. -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZEr3zQAKCRDdBJ7gKXxA jlLoAP0fpQBipwFxED0Us4SKQfupV6z4caXNJGPeay7Aj11/kQD/aMRC2uPfgr96 eMG3kwn2pqkB9ST2QpkaRbxA//eMbQY= =J+Dj -----END PGP SIGNATURE----- Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of switching from a user process to a kernel thread. - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav. - zsmalloc performance improvements from Sergey Senozhatsky. - Yue Zhao has found and fixed some data race issues around the alteration of memcg userspace tunables. - VFS rationalizations from Christoph Hellwig: - removal of most of the callers of write_one_page() - make __filemap_get_folio()'s return value more useful - Luis Chamberlain has changed tmpfs so it no longer requires swap backing. Use `mount -o noswap'. - Qi Zheng has made the slab shrinkers operate locklessly, providing some scalability benefits. - Keith Busch has improved dmapool's performance, making part of its operations O(1) rather than O(n). - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd, permitting userspace to wr-protect anon memory unpopulated ptes. - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather than exclusive, and has fixed a bunch of errors which were caused by its unintuitive meaning. - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature, which causes minor faults to install a write-protected pte. - Vlastimil Babka has done some maintenance work on vma_merge(): cleanups to the kernel code and improvements to our userspace test harness. - Cleanups to do_fault_around() by Lorenzo Stoakes. - Mike Rapoport has moved a lot of initialization code out of various mm/ files and into mm/mm_init.c. - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for DRM, but DRM doesn't use it any more. - Lorenzo has also coverted read_kcore() and vread() to use iterators and has thereby removed the use of bounce buffers in some cases. - Lorenzo has also contributed further cleanups of vma_merge(). - Chaitanya Prakash provides some fixes to the mmap selftesting code. - Matthew Wilcox changes xfs and afs so they no longer take sleeping locks in ->map_page(), a step towards RCUification of pagefaults. - Suren Baghdasaryan has improved mmap_lock scalability by switching to per-VMA locking. - Frederic Weisbecker has reworked the percpu cache draining so that it no longer causes latency glitches on cpu isolated workloads. - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig logic. - Liu Shixin has changed zswap's initialization so we no longer waste a chunk of memory if zswap is not being used. - Yosry Ahmed has improved the performance of memcg statistics flushing. - David Stevens has fixed several issues involving khugepaged, userfaultfd and shmem. - Christoph Hellwig has provided some cleanup work to zram's IO-related code paths. - David Hildenbrand has fixed up some issues in the selftest code's testing of our pte state changing. - Pankaj Raghav has made page_endio() unneeded and has removed it. - Peter Xu contributed some rationalizations of the userfaultfd selftests. - Yosry Ahmed has fixed an issue around memcg's page recalim accounting. - Chaitanya Prakash has fixed some arm-related issues in the selftests/mm code. - Longlong Xia has improved the way in which KSM handles hwpoisoned pages. - Peter Xu fixes a few issues with uffd-wp at fork() time. - Stefan Roesch has changed KSM so that it may now be used on a per-process and per-cgroup basis. * tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm,unmap: avoid flushing TLB in batch if PTE is inaccessible shmem: restrict noswap option to initial user namespace mm/khugepaged: fix conflicting mods to collapse_file() sparse: remove unnecessary 0 values from rc mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area() hugetlb: pte_alloc_huge() to replace huge pte_alloc_map() maple_tree: fix allocation in mas_sparse_area() mm: do not increment pgfault stats when page fault handler retries zsmalloc: allow only one active pool compaction context selftests/mm: add new selftests for KSM mm: add new KSM process and sysfs knobs mm: add new api to enable ksm per process mm: shrinkers: fix debugfs file permissions mm: don't check VMA write permissions if the PTE/PMD indicates write permissions migrate_pages_batch: fix statistics for longterm pin retry userfaultfd: use helper function range_in_vma() lib/show_mem.c: use for_each_populated_zone() simplify code mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list() fs/buffer: convert create_page_buffers to folio_create_buffers fs/buffer: add folio_create_empty_buffers helper ...
432 lines
13 KiB
C
432 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/* Network filesystem high-level buffered read support.
|
|
*
|
|
* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*/
|
|
|
|
#include <linux/export.h>
|
|
#include <linux/task_io_accounting_ops.h>
|
|
#include "internal.h"
|
|
|
|
/*
|
|
* Unlock the folios in a read operation. We need to set PG_fscache on any
|
|
* folios we're going to write back before we unlock them.
|
|
*/
|
|
void netfs_rreq_unlock_folios(struct netfs_io_request *rreq)
|
|
{
|
|
struct netfs_io_subrequest *subreq;
|
|
struct folio *folio;
|
|
pgoff_t start_page = rreq->start / PAGE_SIZE;
|
|
pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1;
|
|
size_t account = 0;
|
|
bool subreq_failed = false;
|
|
|
|
XA_STATE(xas, &rreq->mapping->i_pages, start_page);
|
|
|
|
if (test_bit(NETFS_RREQ_FAILED, &rreq->flags)) {
|
|
__clear_bit(NETFS_RREQ_COPY_TO_CACHE, &rreq->flags);
|
|
list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
|
|
__clear_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags);
|
|
}
|
|
}
|
|
|
|
/* Walk through the pagecache and the I/O request lists simultaneously.
|
|
* We may have a mixture of cached and uncached sections and we only
|
|
* really want to write out the uncached sections. This is slightly
|
|
* complicated by the possibility that we might have huge pages with a
|
|
* mixture inside.
|
|
*/
|
|
subreq = list_first_entry(&rreq->subrequests,
|
|
struct netfs_io_subrequest, rreq_link);
|
|
subreq_failed = (subreq->error < 0);
|
|
|
|
trace_netfs_rreq(rreq, netfs_rreq_trace_unlock);
|
|
|
|
rcu_read_lock();
|
|
xas_for_each(&xas, folio, last_page) {
|
|
loff_t pg_end;
|
|
bool pg_failed = false;
|
|
|
|
if (xas_retry(&xas, folio))
|
|
continue;
|
|
|
|
pg_end = folio_pos(folio) + folio_size(folio) - 1;
|
|
|
|
for (;;) {
|
|
loff_t sreq_end;
|
|
|
|
if (!subreq) {
|
|
pg_failed = true;
|
|
break;
|
|
}
|
|
if (test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags))
|
|
folio_start_fscache(folio);
|
|
pg_failed |= subreq_failed;
|
|
sreq_end = subreq->start + subreq->len - 1;
|
|
if (pg_end < sreq_end)
|
|
break;
|
|
|
|
account += subreq->transferred;
|
|
if (!list_is_last(&subreq->rreq_link, &rreq->subrequests)) {
|
|
subreq = list_next_entry(subreq, rreq_link);
|
|
subreq_failed = (subreq->error < 0);
|
|
} else {
|
|
subreq = NULL;
|
|
subreq_failed = false;
|
|
}
|
|
|
|
if (pg_end == sreq_end)
|
|
break;
|
|
}
|
|
|
|
if (!pg_failed) {
|
|
flush_dcache_folio(folio);
|
|
folio_mark_uptodate(folio);
|
|
}
|
|
|
|
if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) {
|
|
if (folio_index(folio) == rreq->no_unlock_folio &&
|
|
test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags))
|
|
_debug("no unlock");
|
|
else
|
|
folio_unlock(folio);
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
task_io_account_read(account);
|
|
if (rreq->netfs_ops->done)
|
|
rreq->netfs_ops->done(rreq);
|
|
}
|
|
|
|
static void netfs_cache_expand_readahead(struct netfs_io_request *rreq,
|
|
loff_t *_start, size_t *_len, loff_t i_size)
|
|
{
|
|
struct netfs_cache_resources *cres = &rreq->cache_resources;
|
|
|
|
if (cres->ops && cres->ops->expand_readahead)
|
|
cres->ops->expand_readahead(cres, _start, _len, i_size);
|
|
}
|
|
|
|
static void netfs_rreq_expand(struct netfs_io_request *rreq,
|
|
struct readahead_control *ractl)
|
|
{
|
|
/* Give the cache a chance to change the request parameters. The
|
|
* resultant request must contain the original region.
|
|
*/
|
|
netfs_cache_expand_readahead(rreq, &rreq->start, &rreq->len, rreq->i_size);
|
|
|
|
/* Give the netfs a chance to change the request parameters. The
|
|
* resultant request must contain the original region.
|
|
*/
|
|
if (rreq->netfs_ops->expand_readahead)
|
|
rreq->netfs_ops->expand_readahead(rreq);
|
|
|
|
/* Expand the request if the cache wants it to start earlier. Note
|
|
* that the expansion may get further extended if the VM wishes to
|
|
* insert THPs and the preferred start and/or end wind up in the middle
|
|
* of THPs.
|
|
*
|
|
* If this is the case, however, the THP size should be an integer
|
|
* multiple of the cache granule size, so we get a whole number of
|
|
* granules to deal with.
|
|
*/
|
|
if (rreq->start != readahead_pos(ractl) ||
|
|
rreq->len != readahead_length(ractl)) {
|
|
readahead_expand(ractl, rreq->start, rreq->len);
|
|
rreq->start = readahead_pos(ractl);
|
|
rreq->len = readahead_length(ractl);
|
|
|
|
trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl),
|
|
netfs_read_trace_expanded);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* netfs_readahead - Helper to manage a read request
|
|
* @ractl: The description of the readahead request
|
|
*
|
|
* Fulfil a readahead request by drawing data from the cache if possible, or
|
|
* the netfs if not. Space beyond the EOF is zero-filled. Multiple I/O
|
|
* requests from different sources will get munged together. If necessary, the
|
|
* readahead window can be expanded in either direction to a more convenient
|
|
* alighment for RPC efficiency or to make storage in the cache feasible.
|
|
*
|
|
* The calling netfs must initialise a netfs context contiguous to the vfs
|
|
* inode before calling this.
|
|
*
|
|
* This is usable whether or not caching is enabled.
|
|
*/
|
|
void netfs_readahead(struct readahead_control *ractl)
|
|
{
|
|
struct netfs_io_request *rreq;
|
|
struct netfs_inode *ctx = netfs_inode(ractl->mapping->host);
|
|
int ret;
|
|
|
|
_enter("%lx,%x", readahead_index(ractl), readahead_count(ractl));
|
|
|
|
if (readahead_count(ractl) == 0)
|
|
return;
|
|
|
|
rreq = netfs_alloc_request(ractl->mapping, ractl->file,
|
|
readahead_pos(ractl),
|
|
readahead_length(ractl),
|
|
NETFS_READAHEAD);
|
|
if (IS_ERR(rreq))
|
|
return;
|
|
|
|
if (ctx->ops->begin_cache_operation) {
|
|
ret = ctx->ops->begin_cache_operation(rreq);
|
|
if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
|
|
goto cleanup_free;
|
|
}
|
|
|
|
netfs_stat(&netfs_n_rh_readahead);
|
|
trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl),
|
|
netfs_read_trace_readahead);
|
|
|
|
netfs_rreq_expand(rreq, ractl);
|
|
|
|
/* Drop the refs on the folios here rather than in the cache or
|
|
* filesystem. The locks will be dropped in netfs_rreq_unlock().
|
|
*/
|
|
while (readahead_folio(ractl))
|
|
;
|
|
|
|
netfs_begin_read(rreq, false);
|
|
return;
|
|
|
|
cleanup_free:
|
|
netfs_put_request(rreq, false, netfs_rreq_trace_put_failed);
|
|
return;
|
|
}
|
|
EXPORT_SYMBOL(netfs_readahead);
|
|
|
|
/**
|
|
* netfs_read_folio - Helper to manage a read_folio request
|
|
* @file: The file to read from
|
|
* @folio: The folio to read
|
|
*
|
|
* Fulfil a read_folio request by drawing data from the cache if
|
|
* possible, or the netfs if not. Space beyond the EOF is zero-filled.
|
|
* Multiple I/O requests from different sources will get munged together.
|
|
*
|
|
* The calling netfs must initialise a netfs context contiguous to the vfs
|
|
* inode before calling this.
|
|
*
|
|
* This is usable whether or not caching is enabled.
|
|
*/
|
|
int netfs_read_folio(struct file *file, struct folio *folio)
|
|
{
|
|
struct address_space *mapping = folio_file_mapping(folio);
|
|
struct netfs_io_request *rreq;
|
|
struct netfs_inode *ctx = netfs_inode(mapping->host);
|
|
int ret;
|
|
|
|
_enter("%lx", folio_index(folio));
|
|
|
|
rreq = netfs_alloc_request(mapping, file,
|
|
folio_file_pos(folio), folio_size(folio),
|
|
NETFS_READPAGE);
|
|
if (IS_ERR(rreq)) {
|
|
ret = PTR_ERR(rreq);
|
|
goto alloc_error;
|
|
}
|
|
|
|
if (ctx->ops->begin_cache_operation) {
|
|
ret = ctx->ops->begin_cache_operation(rreq);
|
|
if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
|
|
goto discard;
|
|
}
|
|
|
|
netfs_stat(&netfs_n_rh_readpage);
|
|
trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage);
|
|
return netfs_begin_read(rreq, true);
|
|
|
|
discard:
|
|
netfs_put_request(rreq, false, netfs_rreq_trace_put_discard);
|
|
alloc_error:
|
|
folio_unlock(folio);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(netfs_read_folio);
|
|
|
|
/*
|
|
* Prepare a folio for writing without reading first
|
|
* @folio: The folio being prepared
|
|
* @pos: starting position for the write
|
|
* @len: length of write
|
|
* @always_fill: T if the folio should always be completely filled/cleared
|
|
*
|
|
* In some cases, write_begin doesn't need to read at all:
|
|
* - full folio write
|
|
* - write that lies in a folio that is completely beyond EOF
|
|
* - write that covers the folio from start to EOF or beyond it
|
|
*
|
|
* If any of these criteria are met, then zero out the unwritten parts
|
|
* of the folio and return true. Otherwise, return false.
|
|
*/
|
|
static bool netfs_skip_folio_read(struct folio *folio, loff_t pos, size_t len,
|
|
bool always_fill)
|
|
{
|
|
struct inode *inode = folio_inode(folio);
|
|
loff_t i_size = i_size_read(inode);
|
|
size_t offset = offset_in_folio(folio, pos);
|
|
size_t plen = folio_size(folio);
|
|
|
|
if (unlikely(always_fill)) {
|
|
if (pos - offset + len <= i_size)
|
|
return false; /* Page entirely before EOF */
|
|
zero_user_segment(&folio->page, 0, plen);
|
|
folio_mark_uptodate(folio);
|
|
return true;
|
|
}
|
|
|
|
/* Full folio write */
|
|
if (offset == 0 && len >= plen)
|
|
return true;
|
|
|
|
/* Page entirely beyond the end of the file */
|
|
if (pos - offset >= i_size)
|
|
goto zero_out;
|
|
|
|
/* Write that covers from the start of the folio to EOF or beyond */
|
|
if (offset == 0 && (pos + len) >= i_size)
|
|
goto zero_out;
|
|
|
|
return false;
|
|
zero_out:
|
|
zero_user_segments(&folio->page, 0, offset, offset + len, plen);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* netfs_write_begin - Helper to prepare for writing
|
|
* @ctx: The netfs context
|
|
* @file: The file to read from
|
|
* @mapping: The mapping to read from
|
|
* @pos: File position at which the write will begin
|
|
* @len: The length of the write (may extend beyond the end of the folio chosen)
|
|
* @_folio: Where to put the resultant folio
|
|
* @_fsdata: Place for the netfs to store a cookie
|
|
*
|
|
* Pre-read data for a write-begin request by drawing data from the cache if
|
|
* possible, or the netfs if not. Space beyond the EOF is zero-filled.
|
|
* Multiple I/O requests from different sources will get munged together. If
|
|
* necessary, the readahead window can be expanded in either direction to a
|
|
* more convenient alighment for RPC efficiency or to make storage in the cache
|
|
* feasible.
|
|
*
|
|
* The calling netfs must provide a table of operations, only one of which,
|
|
* issue_op, is mandatory.
|
|
*
|
|
* The check_write_begin() operation can be provided to check for and flush
|
|
* conflicting writes once the folio is grabbed and locked. It is passed a
|
|
* pointer to the fsdata cookie that gets returned to the VM to be passed to
|
|
* write_end. It is permitted to sleep. It should return 0 if the request
|
|
* should go ahead or it may return an error. It may also unlock and put the
|
|
* folio, provided it sets ``*foliop`` to NULL, in which case a return of 0
|
|
* will cause the folio to be re-got and the process to be retried.
|
|
*
|
|
* The calling netfs must initialise a netfs context contiguous to the vfs
|
|
* inode before calling this.
|
|
*
|
|
* This is usable whether or not caching is enabled.
|
|
*/
|
|
int netfs_write_begin(struct netfs_inode *ctx,
|
|
struct file *file, struct address_space *mapping,
|
|
loff_t pos, unsigned int len, struct folio **_folio,
|
|
void **_fsdata)
|
|
{
|
|
struct netfs_io_request *rreq;
|
|
struct folio *folio;
|
|
pgoff_t index = pos >> PAGE_SHIFT;
|
|
int ret;
|
|
|
|
DEFINE_READAHEAD(ractl, file, NULL, mapping, index);
|
|
|
|
retry:
|
|
folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN,
|
|
mapping_gfp_mask(mapping));
|
|
if (IS_ERR(folio))
|
|
return PTR_ERR(folio);
|
|
|
|
if (ctx->ops->check_write_begin) {
|
|
/* Allow the netfs (eg. ceph) to flush conflicts. */
|
|
ret = ctx->ops->check_write_begin(file, pos, len, &folio, _fsdata);
|
|
if (ret < 0) {
|
|
trace_netfs_failure(NULL, NULL, ret, netfs_fail_check_write_begin);
|
|
goto error;
|
|
}
|
|
if (!folio)
|
|
goto retry;
|
|
}
|
|
|
|
if (folio_test_uptodate(folio))
|
|
goto have_folio;
|
|
|
|
/* If the page is beyond the EOF, we want to clear it - unless it's
|
|
* within the cache granule containing the EOF, in which case we need
|
|
* to preload the granule.
|
|
*/
|
|
if (!netfs_is_cache_enabled(ctx) &&
|
|
netfs_skip_folio_read(folio, pos, len, false)) {
|
|
netfs_stat(&netfs_n_rh_write_zskip);
|
|
goto have_folio_no_wait;
|
|
}
|
|
|
|
rreq = netfs_alloc_request(mapping, file,
|
|
folio_file_pos(folio), folio_size(folio),
|
|
NETFS_READ_FOR_WRITE);
|
|
if (IS_ERR(rreq)) {
|
|
ret = PTR_ERR(rreq);
|
|
goto error;
|
|
}
|
|
rreq->no_unlock_folio = folio_index(folio);
|
|
__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);
|
|
|
|
if (ctx->ops->begin_cache_operation) {
|
|
ret = ctx->ops->begin_cache_operation(rreq);
|
|
if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
|
|
goto error_put;
|
|
}
|
|
|
|
netfs_stat(&netfs_n_rh_write_begin);
|
|
trace_netfs_read(rreq, pos, len, netfs_read_trace_write_begin);
|
|
|
|
/* Expand the request to meet caching requirements and download
|
|
* preferences.
|
|
*/
|
|
ractl._nr_pages = folio_nr_pages(folio);
|
|
netfs_rreq_expand(rreq, &ractl);
|
|
|
|
/* We hold the folio locks, so we can drop the references */
|
|
folio_get(folio);
|
|
while (readahead_folio(&ractl))
|
|
;
|
|
|
|
ret = netfs_begin_read(rreq, true);
|
|
if (ret < 0)
|
|
goto error;
|
|
|
|
have_folio:
|
|
ret = folio_wait_fscache_killable(folio);
|
|
if (ret < 0)
|
|
goto error;
|
|
have_folio_no_wait:
|
|
*_folio = folio;
|
|
_leave(" = 0");
|
|
return 0;
|
|
|
|
error_put:
|
|
netfs_put_request(rreq, false, netfs_rreq_trace_put_failed);
|
|
error:
|
|
if (folio) {
|
|
folio_unlock(folio);
|
|
folio_put(folio);
|
|
}
|
|
_leave(" = %d", ret);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(netfs_write_begin);
|