Introduce basic skeleton of the new, rewritten fscache driver. Changes ======= ver #3: - Use remove_proc_subtree(), not remove_proc_entry() to remove a populated dir. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> cc: linux-cachefs@xxxxxxxxxx Link: https://lore.kernel.org/r/163819584034.215744.4290533472390439030.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v1 Link: https://lore.kernel.org/r/163906887770.143852.3577888294989185666.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v2 --- fs/Makefile | 1 fs/fscache/Kconfig | 39 +++++++++ fs/fscache/Makefile | 12 +++ fs/fscache/internal.h | 183 ++++++++++++++++++++++++++++++++++++++++ fs/fscache/main.c | 65 ++++++++++++++ fs/fscache/proc.c | 42 +++++++++ fs/fscache/stats.c | 22 +++++ include/linux/fscache-cache.h | 2 include/linux/fscache.h | 6 + include/trace/events/fscache.h | 49 +++++++++++ 10 files changed, 420 insertions(+), 1 deletion(-) create mode 100644 fs/fscache/Makefile create mode 100644 fs/fscache/internal.h create mode 100644 fs/fscache/main.c create mode 100644 fs/fscache/proc.c create mode 100644 fs/fscache/stats.c create mode 100644 include/trace/events/fscache.h diff --git a/fs/Makefile b/fs/Makefile index 23ddd0803d14..290815f3fd31 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -67,6 +67,7 @@ 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 diff --git a/fs/fscache/Kconfig b/fs/fscache/Kconfig index 6440484d9461..76316c4a3fb7 100644 --- a/fs/fscache/Kconfig +++ b/fs/fscache/Kconfig @@ -1,4 +1,43 @@ # SPDX-License-Identifier: GPL-2.0-only +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. + config FSCACHE_OLD_API bool diff --git a/fs/fscache/Makefile b/fs/fscache/Makefile new file mode 100644 index 000000000000..f9722de32247 --- /dev/null +++ b/fs/fscache/Makefile @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for general filesystem caching code +# + +fscache-y := \ + main.o + +fscache-$(CONFIG_PROC_FS) += proc.o +fscache-$(CONFIG_FSCACHE_STATS) += stats.o + +obj-$(CONFIG_FSCACHE) := fscache.o diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h new file mode 100644 index 000000000000..ea52f8594a77 --- /dev/null +++ b/fs/fscache/internal.h @@ -0,0 +1,183 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* Internal definitions for FS-Cache + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@xxxxxxxxxx) + */ + +#ifdef pr_fmt +#undef pr_fmt +#endif + +#define pr_fmt(fmt) "FS-Cache: " fmt + +#include <linux/slab.h> +#include <linux/fscache-cache.h> +#include <trace/events/fscache.h> +#include <linux/sched.h> +#include <linux/seq_file.h> + +/* + * main.c + */ +extern unsigned fscache_debug; + +/* + * proc.c + */ +#ifdef CONFIG_PROC_FS +extern int __init fscache_proc_init(void); +extern void fscache_proc_cleanup(void); +#else +#define fscache_proc_init() (0) +#define fscache_proc_cleanup() do {} while (0) +#endif + +/* + * stats.c + */ +#ifdef CONFIG_FSCACHE_STATS + +static inline void fscache_stat(atomic_t *stat) +{ + atomic_inc(stat); +} + +static inline void fscache_stat_d(atomic_t *stat) +{ + atomic_dec(stat); +} + +#define __fscache_stat(stat) (stat) + +int fscache_stats_show(struct seq_file *m, void *v); +#else + +#define __fscache_stat(stat) (NULL) +#define fscache_stat(stat) do {} while (0) +#define fscache_stat_d(stat) do {} while (0) +#endif + + +/*****************************************************************************/ +/* + * debug tracing + */ +#define dbgprintk(FMT, ...) \ + printk("[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__) + +#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, ...) no_printk(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, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__) +#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__) +#define _debug(FMT, ...) no_printk(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_OBJECT 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))) { \ + pr_err("\n"); \ + pr_err("Assertion failed\n"); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTCMP(X, OP, Y) \ +do { \ + if (unlikely(!((X) OP (Y)))) { \ + pr_err("\n"); \ + pr_err("Assertion failed\n"); \ + pr_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))) { \ + pr_err("\n"); \ + pr_err("Assertion failed\n"); \ + BUG(); \ + } \ +} while (0) + +#define ASSERTIFCMP(C, X, OP, Y) \ +do { \ + if (unlikely((C) && !((X) OP (Y)))) { \ + pr_err("\n"); \ + pr_err("Assertion failed\n"); \ + pr_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..819de2ee1276 --- /dev/null +++ b/fs/fscache/main.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* General filesystem local caching manager + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@xxxxxxxxxx) + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include <linux/module.h> +#include <linux/init.h> +#define CREATE_TRACE_POINTS +#include "internal.h" + +MODULE_DESCRIPTION("FS Cache Manager"); +MODULE_AUTHOR("Red Hat, Inc."); +MODULE_LICENSE("GPL"); + +unsigned fscache_debug; +module_param_named(debug, fscache_debug, uint, + S_IWUSR | S_IRUGO); +MODULE_PARM_DESC(fscache_debug, + "FS-Cache debugging mask"); + +struct workqueue_struct *fscache_wq; +EXPORT_SYMBOL(fscache_wq); + +/* + * initialise the fs caching module + */ +static int __init fscache_init(void) +{ + int ret = -ENOMEM; + + fscache_wq = alloc_workqueue("fscache", WQ_UNBOUND | WQ_FREEZABLE, 0); + if (!fscache_wq) + goto error_wq; + + ret = fscache_proc_init(); + if (ret < 0) + goto error_proc; + + pr_notice("Loaded\n"); + return 0; + +error_proc: + destroy_workqueue(fscache_wq); +error_wq: + return ret; +} + +fs_initcall(fscache_init); + +/* + * clean up on module removal + */ +static void __exit fscache_exit(void) +{ + _enter(""); + + fscache_proc_cleanup(); + destroy_workqueue(fscache_wq); + pr_notice("Unloaded\n"); +} + +module_exit(fscache_exit); diff --git a/fs/fscache/proc.c b/fs/fscache/proc.c new file mode 100644 index 000000000000..4d866ac41776 --- /dev/null +++ b/fs/fscache/proc.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* FS-Cache statistics viewing interface + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@xxxxxxxxxx) + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include <linux/module.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include "internal.h" + +/* + * initialise the /proc/fs/fscache/ directory + */ +int __init fscache_proc_init(void) +{ + if (!proc_mkdir("fs/fscache", NULL)) + goto error_dir; + +#ifdef CONFIG_FSCACHE_STATS + if (!proc_create_single("fs/fscache/stats", S_IFREG | 0444, NULL, + fscache_stats_show)) + goto error; +#endif + + return 0; + +error: + remove_proc_entry("fs/fscache", NULL); +error_dir: + return -ENOMEM; +} + +/* + * clean up the /proc/fs/fscache/ directory + */ +void fscache_proc_cleanup(void) +{ + remove_proc_subtree("fs/fscache", NULL); +} diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c new file mode 100644 index 000000000000..bd92f93e1680 --- /dev/null +++ b/fs/fscache/stats.c @@ -0,0 +1,22 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* FS-Cache statistics + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@xxxxxxxxxx) + */ + +#define FSCACHE_DEBUG_LEVEL CACHE +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include "internal.h" + +/* + * display the general statistics + */ +int fscache_stats_show(struct seq_file *m, void *v) +{ + seq_puts(m, "FS-Cache statistics\n"); + + netfs_stats_show(m); + return 0; +} diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index 47f21a53ac4b..d6910a913918 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -16,4 +16,6 @@ #include <linux/fscache.h> +extern struct workqueue_struct *fscache_wq; + #endif /* _LINUX_FSCACHE_CACHE_H */ diff --git a/include/linux/fscache.h b/include/linux/fscache.h index 0364a4ca16f6..1cf90c252aac 100644 --- a/include/linux/fscache.h +++ b/include/linux/fscache.h @@ -1,7 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0-or-later */ /* General filesystem caching interface * - * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@xxxxxxxxxx) * * NOTE!!! See: @@ -18,9 +18,13 @@ #include <linux/netfs.h> #if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE) +#define __fscache_available (1) +#define fscache_available() (1) #define fscache_cookie_valid(cookie) (cookie) #define fscache_cookie_enabled(cookie) (cookie) #else +#define __fscache_available (0) +#define fscache_available() (0) #define fscache_cookie_valid(cookie) (0) #define fscache_cookie_enabled(cookie) (0) #endif diff --git a/include/trace/events/fscache.h b/include/trace/events/fscache.h new file mode 100644 index 000000000000..fe214c5cc87f --- /dev/null +++ b/include/trace/events/fscache.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* FS-Cache tracepoints + * + * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@xxxxxxxxxx) + */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM fscache + +#if !defined(_TRACE_FSCACHE_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_FSCACHE_H + +#include <linux/fscache.h> +#include <linux/tracepoint.h> + +/* + * Define enums for tracing information. + */ +#ifndef __FSCACHE_DECLARE_TRACE_ENUMS_ONCE_ONLY +#define __FSCACHE_DECLARE_TRACE_ENUMS_ONCE_ONLY + +#endif + +/* + * Declare tracing information enums and their string mappings for display. + */ + +/* + * Export enum symbols via userspace. + */ +#undef EM +#undef E_ +#define EM(a, b) TRACE_DEFINE_ENUM(a); +#define E_(a, b) TRACE_DEFINE_ENUM(a); + +/* + * Now redefine the EM() and E_() macros to map the enums to the strings that + * will be printed in the output. + */ +#undef EM +#undef E_ +#define EM(a, b) { a, b }, +#define E_(a, b) { a, b } + + +#endif /* _TRACE_FSCACHE_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h>
