4 files changed, 270 insertions, 0 deletions

diff --git a/fs/fscache/Kconfig b/fs/fscache/Kconfig
new file mode 100644
index 000000000000..7c7bccd5eee4
--- /dev/null
+++ b/fs/fscache/Kconfig
@@ -0,0 +1,22 @@
+
+config FSCACHE
+        tristate "General filesystem local caching manager"
+        depends on EXPERIMENTAL
+        select SLOW_WORK
+        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.txt 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.txt for more information.
diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile
new file mode 100644
index 000000000000..f8038b83e0ef
--- /dev/null
+++ b/fs/fscache/Makefile
@@ -0,0 +1,8 @@
+#
+# Makefile for general filesystem caching code
+#
+
+fscache-y := \
+        main.o
+
+obj-$(CONFIG_FSCACHE) := fscache.o
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
new file mode 100644
index 000000000000..95dc92da7152
--- /dev/null
+++ b/fs/fscache/internal.h
@@ -0,0 +1,165 @@
+/* Internal definitions for FS-Cache
+ *
+ * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+/*
+ * Lock order, in the order in which multiple locks should be obtained:
+ * - fscache_addremove_sem
+ * - cookie->lock
+ * - cookie->parent->lock
+ * - cache->object_list_lock
+ * - object->lock
+ * - object->parent->lock
+ * - fscache_thread_lock
+ *
+ */
+
+#include <linux/fscache-cache.h>
+#include <linux/sched.h>
+
+#define FSCACHE_MIN_THREADS     4
+#define FSCACHE_MAX_THREADS     32
+
+/*
+ * fsc-main.c
+ */
+extern unsigned fscache_defer_lookup;
+extern unsigned fscache_defer_create;
+extern unsigned fscache_debug;
+extern struct kobject *fscache_root;
+
+/*****************************************************************************/
+/*
+ * debug tracing
+ */
+#define dbgprintk(FMT, ...) \
+        printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)
+
+/* make sure we maintain the format strings, even when debugging is disabled */
+static inline __attribute__((format(printf, 1, 2)))
+void _dbprintk(const char *fmt, ...)
+{
+}
+
+#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
+#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)
+
+#define kjournal(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
+
+#ifdef __KDEBUG
+#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
+#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
+#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)
+
+#elif defined(CONFIG_FSCACHE_DEBUG)
+#define _enter(FMT, ...)                        \
+do {                                            \
+        if (__do_kdebug(ENTER))                 \
+                kenter(FMT, ##__VA_ARGS__);     \
+} while (0)
+
+#define _leave(FMT, ...)                        \
+do {                                            \
+        if (__do_kdebug(LEAVE))                 \
+                kleave(FMT, ##__VA_ARGS__);     \
+} while (0)
+
+#define _debug(FMT, ...)                        \
+do {                                            \
+        if (__do_kdebug(DEBUG))                 \
+                kdebug(FMT, ##__VA_ARGS__);     \
+} while (0)
+
+#else
+#define _enter(FMT, ...) _dbprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
+#define _leave(FMT, ...) _dbprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
+#define _debug(FMT, ...) _dbprintk(FMT, ##__VA_ARGS__)
+#endif
+
+/*
+ * determine whether a particular optional debugging point should be logged
+ * - we need to go through three steps to persuade cpp to correctly join the
+ *   shorthand in FSCACHE_DEBUG_LEVEL with its prefix
+ */
+#define ____do_kdebug(LEVEL, POINT) \
+        unlikely((fscache_debug & \
+                  (FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3))))
+#define ___do_kdebug(LEVEL, POINT) \
+        ____do_kdebug(LEVEL, POINT)
+#define __do_kdebug(POINT) \
+        ___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT)
+
+#define FSCACHE_DEBUG_CACHE     0
+#define FSCACHE_DEBUG_COOKIE    1
+#define FSCACHE_DEBUG_PAGE      2
+#define FSCACHE_DEBUG_OPERATION 3
+
+#define FSCACHE_POINT_ENTER     1
+#define FSCACHE_POINT_LEAVE     2
+#define FSCACHE_POINT_DEBUG     4
+
+#ifndef FSCACHE_DEBUG_LEVEL
+#define FSCACHE_DEBUG_LEVEL CACHE
+#endif
+
+/*
+ * assertions
+ */
+#if 1 /* defined(__KDEBUGALL) */
+
+#define ASSERT(X)                                                       \
+do {                                                                    \
+        if (unlikely(!(X))) {                                           \
+                printk(KERN_ERR "\n");                                  \
+                printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
+#define ASSERTCMP(X, OP, Y)                                             \
+do {                                                                    \
+        if (unlikely(!((X) OP (Y)))) {                                  \
+                printk(KERN_ERR "\n");                                  \
+                printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
+                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
+                       (unsigned long)(X), (unsigned long)(Y));         \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
+#define ASSERTIF(C, X)                                                  \
+do {                                                                    \
+        if (unlikely((C) && !(X))) {                                    \
+                printk(KERN_ERR "\n");                                  \
+                printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
+#define ASSERTIFCMP(C, X, OP, Y)                                        \
+do {                                                                    \
+        if (unlikely((C) && !((X) OP (Y)))) {                           \
+                printk(KERN_ERR "\n");                                  \
+                printk(KERN_ERR "FS-Cache: Assertion failed\n");        \
+                printk(KERN_ERR "%lx " #OP " %lx is false\n",           \
+                       (unsigned long)(X), (unsigned long)(Y));         \
+                BUG();                                                  \
+        }                                                               \
+} while (0)
+
+#else
+
+#define ASSERT(X)                       do {} while (0)
+#define ASSERTCMP(X, OP, Y)             do {} while (0)
+#define ASSERTIF(C, X)                  do {} while (0)
+#define ASSERTIFCMP(C, X, OP, Y)        do {} while (0)
+
+#endif /* assert or not */
diff --git a/fs/fscache/main.c b/fs/fscache/main.c
new file mode 100644
index 000000000000..76f7c69079c0
--- /dev/null
+++ b/fs/fscache/main.c
@@ -0,0 +1,75 @@
+/* General filesystem local caching manager
+ *
+ * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#define FSCACHE_DEBUG_LEVEL CACHE
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/completion.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+MODULE_DESCRIPTION("FS Cache Manager");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+
+unsigned fscache_defer_lookup = 1;
+module_param_named(defer_lookup, fscache_defer_lookup, uint,
+                   S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(fscache_defer_lookup,
+                 "Defer cookie lookup to background thread");
+
+unsigned fscache_defer_create = 1;
+module_param_named(defer_create, fscache_defer_create, uint,
+                   S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(fscache_defer_create,
+                 "Defer cookie creation to background thread");
+
+unsigned fscache_debug;
+module_param_named(debug, fscache_debug, uint,
+                   S_IWUSR | S_IRUGO);
+MODULE_PARM_DESC(fscache_debug,
+                 "FS-Cache debugging mask");
+
+struct kobject *fscache_root;
+
+/*
+ * initialise the fs caching module
+ */
+static int __init fscache_init(void)
+{
+        int ret;
+
+        ret = slow_work_register_user();
+        if (ret < 0)
+                goto error_slow_work;
+
+        printk(KERN_NOTICE "FS-Cache: Loaded\n");
+        return 0;
+
+error_slow_work:
+        return ret;
+}
+
+fs_initcall(fscache_init);
+
+/*
+ * clean up on module removal
+ */
+static void __exit fscache_exit(void)
+{
+        _enter("");
+
+        slow_work_unregister_user();
+        printk(KERN_NOTICE "FS-Cache: Unloaded\n");
+}
+
+module_exit(fscache_exit);