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authorDavid Howells <dhowells@redhat.com>2021-10-21 11:05:53 +0100
committerDavid Howells <dhowells@redhat.com>2022-01-07 13:42:44 +0000
commit287fd611238dd4b7e32fd3a8985aa387d26c4f29 (patch)
tree3b643ab9271c8ac0583840042286355fe27b6592 /fs/cachefiles
parent1f08c925e7a38002bde509e66f6f891468848511 (diff)
downloadlinux-287fd611238dd4b7e32fd3a8985aa387d26c4f29.tar.bz2
cachefiles: Implement begin and end I/O operation
Implement the methods for beginning and ending an I/O operation. When called to begin an I/O operation, we are guaranteed that the cookie has reached a certain stage (we're called by fscache after it has done a suitable wait). If a file is available, we paste a ref over into the cache resources for the I/O routines to use. This means that the object can be invalidated whilst the I/O is ongoing without the need to synchronise as the file pointer in the object is replaced, but the file pointer in the cache resources is unaffected. Ending the operation just requires ditching any refs we have and dropping the access guarantee that fscache got for us on the cookie. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/r/163819645033.215744.2199344081658268312.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906951916.143852.9531384743995679857.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967161222.1823006.4461476204800357263.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021559030.640689.3684291785218094142.stgit@warthog.procyon.org.uk/ # v4
Diffstat (limited to 'fs/cachefiles')
-rw-r--r--fs/cachefiles/Makefile1
-rw-r--r--fs/cachefiles/interface.c1
-rw-r--r--fs/cachefiles/internal.h18
-rw-r--r--fs/cachefiles/io.c57
4 files changed, 77 insertions, 0 deletions
diff --git a/fs/cachefiles/Makefile b/fs/cachefiles/Makefile
index cb7a6bcf51eb..16d811f1a2fa 100644
--- a/fs/cachefiles/Makefile
+++ b/fs/cachefiles/Makefile
@@ -7,6 +7,7 @@ cachefiles-y := \
cache.o \
daemon.o \
interface.o \
+ io.o \
key.o \
main.o \
namei.o \
diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c
index e47c52c34071..ad9d311413ff 100644
--- a/fs/cachefiles/interface.c
+++ b/fs/cachefiles/interface.c
@@ -362,5 +362,6 @@ const struct fscache_cache_ops cachefiles_cache_ops = {
.lookup_cookie = cachefiles_lookup_cookie,
.withdraw_cookie = cachefiles_withdraw_cookie,
.invalidate_cookie = cachefiles_invalidate_cookie,
+ .begin_operation = cachefiles_begin_operation,
.prepare_to_write = cachefiles_prepare_to_write,
};
diff --git a/fs/cachefiles/internal.h b/fs/cachefiles/internal.h
index d7aae04edc61..d5868f5514d3 100644
--- a/fs/cachefiles/internal.h
+++ b/fs/cachefiles/internal.h
@@ -105,6 +105,18 @@ struct cachefiles_cache {
#include <trace/events/cachefiles.h>
+static inline
+struct file *cachefiles_cres_file(struct netfs_cache_resources *cres)
+{
+ return cres->cache_priv2;
+}
+
+static inline
+struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *cres)
+{
+ return fscache_cres_cookie(cres)->cache_priv;
+}
+
/*
* note change of state for daemon
*/
@@ -178,6 +190,12 @@ extern void cachefiles_put_object(struct cachefiles_object *object,
enum cachefiles_obj_ref_trace why);
/*
+ * io.c
+ */
+extern bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
+ enum fscache_want_state want_state);
+
+/*
* key.c
*/
extern bool cachefiles_cook_key(struct cachefiles_object *object);
diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
new file mode 100644
index 000000000000..adeb9a42fd7b
--- /dev/null
+++ b/fs/cachefiles/io.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* kiocb-using read/write
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/mount.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/uio.h>
+#include <linux/falloc.h>
+#include <linux/sched/mm.h>
+#include <trace/events/fscache.h>
+#include "internal.h"
+
+/*
+ * Clean up an operation.
+ */
+static void cachefiles_end_operation(struct netfs_cache_resources *cres)
+{
+ struct file *file = cachefiles_cres_file(cres);
+
+ if (file)
+ fput(file);
+ fscache_end_cookie_access(fscache_cres_cookie(cres), fscache_access_io_end);
+}
+
+static const struct netfs_cache_ops cachefiles_netfs_cache_ops = {
+ .end_operation = cachefiles_end_operation,
+};
+
+/*
+ * Open the cache file when beginning a cache operation.
+ */
+bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
+ enum fscache_want_state want_state)
+{
+ struct cachefiles_object *object = cachefiles_cres_object(cres);
+
+ if (!cachefiles_cres_file(cres)) {
+ cres->ops = &cachefiles_netfs_cache_ops;
+ if (object->file) {
+ spin_lock(&object->lock);
+ if (!cres->cache_priv2 && object->file)
+ cres->cache_priv2 = get_file(object->file);
+ spin_unlock(&object->lock);
+ }
+ }
+
+ if (!cachefiles_cres_file(cres) && want_state != FSCACHE_WANT_PARAMS) {
+ pr_err("failed to get cres->file\n");
+ return false;
+ }
+
+ return true;
+}