netfs, fscache: Move fs/fscache/* into fs/netfs/

There's a problem with dependencies between netfslib and fscache as each
wants to access some functions of the other.  Deal with this by moving
fs/fscache/* into fs/netfs/ and renaming those files to begin with
"fscache-".

For the moment, the moved files are changed as little as possible and an
fscache module is still built.  A subsequent patch will integrate them.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Christian Brauner <christian@brauner.io>
cc: linux-fsdevel@vger.kernel.org
cc: linux-cachefs@redhat.com

MAINTAINERS

@@ -8133,6 +8133,19 @@ S:	Supported
 F:	fs/iomap/
 F:	include/linux/iomap.h
 
+FILESYSTEMS [NETFS LIBRARY]
+M:	David Howells <dhowells@redhat.com>
+L:	linux-cachefs@redhat.com (moderated for non-subscribers)
+L:	linux-fsdevel@vger.kernel.org
+S:	Supported
+F:	Documentation/filesystems/caching/
+F:	Documentation/filesystems/netfs_library.rst
+F:	fs/netfs/
+F:	include/linux/fscache*.h
+F:	include/linux/netfs.h
+F:	include/trace/events/fscache.h
+F:	include/trace/events/netfs.h
+
 FINTEK F75375S HARDWARE MONITOR AND FAN CONTROLLER DRIVER
 M:	Riku Voipio <riku.voipio@iki.fi>
 L:	linux-hwmon@vger.kernel.org
@@ -8567,14 +8580,6 @@ F:	Documentation/power/freezing-of-tasks.rst
 F:	include/linux/freezer.h
 F:	kernel/freezer.c
 
-FS-CACHE: LOCAL CACHING FOR NETWORK FILESYSTEMS
-M:	David Howells <dhowells@redhat.com>
-L:	linux-cachefs@redhat.com (moderated for non-subscribers)
-S:	Supported
-F:	Documentation/filesystems/caching/
-F:	fs/fscache/
-F:	include/linux/fscache*.h
-
 FSCRYPT: FILE SYSTEM LEVEL ENCRYPTION SUPPORT
 M:	Eric Biggers <ebiggers@kernel.org>
 M:	Theodore Y. Ts'o <tytso@mit.edu>

fs/Kconfig

@@ -140,7 +140,6 @@ source "fs/overlayfs/Kconfig"
 menu "Caches"
 
 source "fs/netfs/Kconfig"
-source "fs/fscache/Kconfig"
 source "fs/cachefiles/Kconfig"
 
 endmenu

fs/Makefile

@@ -60,7 +60,6 @@ obj-$(CONFIG_DLM)		+= dlm/
 
 # Do not add any filesystems before this line
 obj-$(CONFIG_NETFS_SUPPORT)	+= netfs/
-obj-$(CONFIG_FSCACHE)		+= fscache/
 obj-$(CONFIG_REISERFS_FS)	+= reiserfs/
 obj-$(CONFIG_EXT4_FS)		+= ext4/
 # We place ext4 before ext2 so that clean ext3 root fs's do NOT mount using the

fs/netfs/Kconfig

@@ -21,3 +21,42 @@ config NETFS_STATS
 	  multi-CPU system these may be on cachelines that keep bouncing
 	  between CPUs.  On the other hand, the stats are very useful for
 	  debugging purposes.  Saying 'Y' here is recommended.
+
+config FSCACHE
+	tristate "General filesystem local caching manager"
+	select NETFS_SUPPORT
+	help
+	  This option enables a generic filesystem caching manager that can be
+	  used by various network and other filesystems to cache data locally.
+	  Different sorts of caches can be plugged in, depending on the
+	  resources available.
+
+	  See Documentation/filesystems/caching/fscache.rst for more information.
+
+config FSCACHE_STATS
+	bool "Gather statistical information on local caching"
+	depends on FSCACHE && PROC_FS
+	select NETFS_STATS
+	help
+	  This option causes statistical information to be gathered on local
+	  caching and exported through file:
+
+		/proc/fs/fscache/stats
+
+	  The gathering of statistics adds a certain amount of overhead to
+	  execution as there are a quite a few stats gathered, and on a
+	  multi-CPU system these may be on cachelines that keep bouncing
+	  between CPUs.  On the other hand, the stats are very useful for
+	  debugging purposes.  Saying 'Y' here is recommended.
+
+	  See Documentation/filesystems/caching/fscache.rst for more information.
+
+config FSCACHE_DEBUG
+	bool "Debug FS-Cache"
+	depends on FSCACHE
+	help
+	  This permits debugging to be dynamically enabled in the local caching
+	  management module.  If this is set, the debugging output may be
+	  enabled by setting bits in /sys/modules/fscache/parameter/debug.
+
+	  See Documentation/filesystems/caching/fscache.rst for more information.

fs/netfs/Makefile

@@ -1,5 +1,17 @@
 # SPDX-License-Identifier: GPL-2.0
 
+fscache-y := \
+	fscache_cache.o \
+	fscache_cookie.o \
+	fscache_io.o \
+	fscache_main.o \
+	fscache_volume.o
+
+fscache-$(CONFIG_PROC_FS) += fscache_proc.o
+fscache-$(CONFIG_FSCACHE_STATS) += fscache_stats.o
+
+obj-$(CONFIG_FSCACHE) := fscache.o
+
 netfs-y := \
 	buffered_read.o \
 	io.o \
@@ -9,4 +21,4 @@ netfs-y := \
 
 netfs-$(CONFIG_NETFS_STATS) += stats.o
 
-obj-$(CONFIG_NETFS_SUPPORT) := netfs.o
+obj-$(CONFIG_NETFS_SUPPORT) += netfs.o

fs/netfs/internal.h

@@ -5,9 +5,12 @@
  * Written by David Howells (dhowells@redhat.com)
  */
 
+#include <linux/slab.h>
+#include <linux/seq_file.h>
 #include <linux/netfs.h>
 #include <linux/fscache.h>
 #include <trace/events/netfs.h>
+#include "fscache_internal.h"
 
 #ifdef pr_fmt
 #undef pr_fmt
@@ -107,6 +110,7 @@ static inline bool netfs_is_cache_enabled(struct netfs_inode *ctx)
 /*
  * debug tracing
  */
+#if 0
 #define dbgprintk(FMT, ...) \
 	printk("[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
 
@@ -143,3 +147,4 @@ do {						\
 #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 #endif
+#endif

fs/netfs/main.c

@@ -8,8 +8,8 @@
 #include <linux/module.h>
 #include <linux/export.h>
 #include "internal.h"
-#define CREATE_TRACE_POINTS
-#include <trace/events/netfs.h>
+//#define CREATE_TRACE_POINTS
+//#include <trace/events/netfs.h>
 
 MODULE_DESCRIPTION("Network fs support");
 MODULE_AUTHOR("Red Hat, Inc.");
@@ -18,3 +18,4 @@ MODULE_LICENSE("GPL");
 unsigned netfs_debug;
 module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
 MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
+