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From:   David Howells <dhowells@redhat.com>
To:     Jeff Layton <jlayton@kernel.org>, Steve French <smfrench@gmail.com>
Cc:     David Howells <dhowells@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Marc Dionne <marc.dionne@auristor.com>,
        Paulo Alcantara <pc@manguebit.com>,
        Shyam Prasad N <sprasad@microsoft.com>,
        Tom Talpey <tom@talpey.com>,
        Dominique Martinet <asmadeus@codewreck.org>,
        Eric Van Hensbergen <ericvh@kernel.org>,
        Ilya Dryomov <idryomov@gmail.com>,
        Christian Brauner <christian@brauner.io>,
        linux-cachefs@redhat.com, linux-afs@lists.infradead.org,
        linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org,
        ceph-devel@vger.kernel.org, v9fs@lists.linux.dev,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4 04/39] netfs, fscache: Move /proc/fs/fscache to /proc/fs/netfs and put in a symlink
Date:   Wed, 13 Dec 2023 15:23:14 +0000
Message-ID: <20231213152350.431591-5-dhowells@redhat.com>
In-Reply-To: <20231213152350.431591-1-dhowells@redhat.com>
References: <20231213152350.431591-1-dhowells@redhat.com>
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Rename /proc/fs/fscache to "netfs" and make a symlink from fscache to that.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Christian Brauner <christian@brauner.io>
cc: linux-fsdevel@vger.kernel.org
cc: linux-cachefs@redhat.com
---
 fs/netfs/fscache_main.c  |  8 ++------
 fs/netfs/fscache_proc.c  | 23 ++++++++---------------
 fs/netfs/fscache_stats.c |  4 +---
 fs/netfs/internal.h      | 12 +++++++++++-
 fs/netfs/main.c          | 33 +++++++++++++++++++++++++++++++++
 fs/netfs/stats.c         | 13 +++++++------
 include/linux/netfs.h    |  1 -
 7 files changed, 62 insertions(+), 32 deletions(-)

diff --git a/fs/netfs/fscache_main.c b/fs/netfs/fscache_main.c
index 00600a4d9ce5..42e98bb523e3 100644
--- a/fs/netfs/fscache_main.c
+++ b/fs/netfs/fscache_main.c
@@ -62,7 +62,7 @@ unsigned int fscache_hash(unsigned int salt, const void *data, size_t len)
 /*
  * initialise the fs caching module
  */
-static int __init fscache_init(void)
+int __init fscache_init(void)
 {
 	int ret = -ENOMEM;
 
@@ -94,12 +94,10 @@ static int __init fscache_init(void)
 	return ret;
 }
 
-fs_initcall(fscache_init);
-
 /*
  * clean up on module removal
  */
-static void __exit fscache_exit(void)
+void __exit fscache_exit(void)
 {
 	_enter("");
 
@@ -108,5 +106,3 @@ static void __exit fscache_exit(void)
 	destroy_workqueue(fscache_wq);
 	pr_notice("FS-Cache unloaded\n");
 }
-
-module_exit(fscache_exit);
diff --git a/fs/netfs/fscache_proc.c b/fs/netfs/fscache_proc.c
index dc3b0e9c8cce..ecd0d1edafaa 100644
--- a/fs/netfs/fscache_proc.c
+++ b/fs/netfs/fscache_proc.c
@@ -12,41 +12,34 @@
 #include "internal.h"
 
 /*
- * initialise the /proc/fs/fscache/ directory
+ * Add files to /proc/fs/netfs/.
  */
 int __init fscache_proc_init(void)
 {
-	if (!proc_mkdir("fs/fscache", NULL))
-		goto error_dir;
+	if (!proc_symlink("fs/fscache", NULL, "../netfs"))
+		goto error_sym;
 
-	if (!proc_create_seq("fs/fscache/caches", S_IFREG | 0444, NULL,
+	if (!proc_create_seq("fs/netfs/caches", S_IFREG | 0444, NULL,
 			     &fscache_caches_seq_ops))
 		goto error;
 
-	if (!proc_create_seq("fs/fscache/volumes", S_IFREG | 0444, NULL,
+	if (!proc_create_seq("fs/netfs/volumes", S_IFREG | 0444, NULL,
 			     &fscache_volumes_seq_ops))
 		goto error;
 
-	if (!proc_create_seq("fs/fscache/cookies", S_IFREG | 0444, NULL,
+	if (!proc_create_seq("fs/netfs/cookies", S_IFREG | 0444, NULL,
 			     &fscache_cookies_seq_ops))
 		goto error;
-
-#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:
+error_sym:
 	return -ENOMEM;
 }
 
 /*
- * clean up the /proc/fs/fscache/ directory
+ * Clean up the /proc/fs/fscache symlink.
  */
 void fscache_proc_cleanup(void)
 {
diff --git a/fs/netfs/fscache_stats.c b/fs/netfs/fscache_stats.c
index fc94e5e79f1c..aad812ead398 100644
--- a/fs/netfs/fscache_stats.c
+++ b/fs/netfs/fscache_stats.c
@@ -52,7 +52,7 @@ EXPORT_SYMBOL(fscache_n_culled);
 /*
  * display the general statistics
  */
-int fscache_stats_show(struct seq_file *m, void *v)
+int fscache_stats_show(struct seq_file *m)
 {
 	seq_puts(m, "FS-Cache statistics\n");
 	seq_printf(m, "Cookies: n=%d v=%d vcol=%u voom=%u\n",
@@ -96,7 +96,5 @@ int fscache_stats_show(struct seq_file *m, void *v)
 	seq_printf(m, "IO     : rd=%u wr=%u\n",
 		   atomic_read(&fscache_n_read),
 		   atomic_read(&fscache_n_write));
-
-	netfs_stats_show(m);
 	return 0;
 }
diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h
index 43769ac606e8..a15fe67e1db7 100644
--- a/fs/netfs/internal.h
+++ b/fs/netfs/internal.h
@@ -76,6 +76,7 @@ extern atomic_t netfs_n_rh_write_done;
 extern atomic_t netfs_n_rh_write_failed;
 extern atomic_t netfs_n_rh_write_zskip;
 
+int netfs_stats_show(struct seq_file *m, void *v);
 
 static inline void netfs_stat(atomic_t *stat)
 {
@@ -166,6 +167,13 @@ static inline void fscache_see_cookie(struct fscache_cookie *cookie,
  * fscache-main.c
  */
 extern unsigned int fscache_hash(unsigned int salt, const void *data, size_t len);
+#ifdef CONFIG_PROC_FS
+int __init fscache_init(void);
+void __exit fscache_exit(void);
+#else
+static inline int fscache_init(void) { return 0; }
+static inline void fscache_exit(void) {}
+#endif
 
 /*
  * fscache-proc.c
@@ -216,12 +224,14 @@ static inline void fscache_stat_d(atomic_t *stat)
 
 #define __fscache_stat(stat) (stat)
 
-int fscache_stats_show(struct seq_file *m, void *v);
+int fscache_stats_show(struct seq_file *m);
 #else
 
 #define __fscache_stat(stat) (NULL)
 #define fscache_stat(stat) do {} while (0)
 #define fscache_stat_d(stat) do {} while (0)
+
+static inline int fscache_stats_show(struct seq_file *m) { return 0; }
 #endif
 
 /*
diff --git a/fs/netfs/main.c b/fs/netfs/main.c
index 1ba8091fcf3e..c9af6e0896d3 100644
--- a/fs/netfs/main.c
+++ b/fs/netfs/main.c
@@ -7,6 +7,8 @@
 
 #include <linux/module.h>
 #include <linux/export.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
 #include "internal.h"
 #define CREATE_TRACE_POINTS
 #include <trace/events/netfs.h>
@@ -19,3 +21,34 @@ unsigned netfs_debug;
 module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
 MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
 
+static int __init netfs_init(void)
+{
+	int ret = -ENOMEM;
+
+	if (!proc_mkdir("fs/netfs", NULL))
+		goto error;
+
+#ifdef CONFIG_FSCACHE_STATS
+	if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
+				netfs_stats_show))
+		goto error_proc;
+#endif
+
+	ret = fscache_init();
+	if (ret < 0)
+		goto error_proc;
+	return 0;
+
+error_proc:
+	remove_proc_entry("fs/netfs", NULL);
+error:
+	return ret;
+}
+fs_initcall(netfs_init);
+
+static void __exit netfs_exit(void)
+{
+	fscache_exit();
+	remove_proc_entry("fs/netfs", NULL);
+}
+module_exit(netfs_exit);
diff --git a/fs/netfs/stats.c b/fs/netfs/stats.c
index 5510a7a14a40..6025dc485f7e 100644
--- a/fs/netfs/stats.c
+++ b/fs/netfs/stats.c
@@ -28,31 +28,32 @@ atomic_t netfs_n_rh_write_done;
 atomic_t netfs_n_rh_write_failed;
 atomic_t netfs_n_rh_write_zskip;
 
-void netfs_stats_show(struct seq_file *m)
+int netfs_stats_show(struct seq_file *m, void *v)
 {
-	seq_printf(m, "RdHelp : RA=%u RP=%u WB=%u WBZ=%u rr=%u sr=%u\n",
+	seq_printf(m, "Netfs  : RA=%u RP=%u WB=%u WBZ=%u rr=%u sr=%u\n",
 		   atomic_read(&netfs_n_rh_readahead),
 		   atomic_read(&netfs_n_rh_readpage),
 		   atomic_read(&netfs_n_rh_write_begin),
 		   atomic_read(&netfs_n_rh_write_zskip),
 		   atomic_read(&netfs_n_rh_rreq),
 		   atomic_read(&netfs_n_rh_sreq));
-	seq_printf(m, "RdHelp : ZR=%u sh=%u sk=%u\n",
+	seq_printf(m, "Netfs  : ZR=%u sh=%u sk=%u\n",
 		   atomic_read(&netfs_n_rh_zero),
 		   atomic_read(&netfs_n_rh_short_read),
 		   atomic_read(&netfs_n_rh_write_zskip));
-	seq_printf(m, "RdHelp : DL=%u ds=%u df=%u di=%u\n",
+	seq_printf(m, "Netfs  : DL=%u ds=%u df=%u di=%u\n",
 		   atomic_read(&netfs_n_rh_download),
 		   atomic_read(&netfs_n_rh_download_done),
 		   atomic_read(&netfs_n_rh_download_failed),
 		   atomic_read(&netfs_n_rh_download_instead));
-	seq_printf(m, "RdHelp : RD=%u rs=%u rf=%u\n",
+	seq_printf(m, "Netfs  : RD=%u rs=%u rf=%u\n",
 		   atomic_read(&netfs_n_rh_read),
 		   atomic_read(&netfs_n_rh_read_done),
 		   atomic_read(&netfs_n_rh_read_failed));
-	seq_printf(m, "RdHelp : WR=%u ws=%u wf=%u\n",
+	seq_printf(m, "Netfs  : WR=%u ws=%u wf=%u\n",
 		   atomic_read(&netfs_n_rh_write),
 		   atomic_read(&netfs_n_rh_write_done),
 		   atomic_read(&netfs_n_rh_write_failed));
+	return fscache_stats_show(m);
 }
 EXPORT_SYMBOL(netfs_stats_show);
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index d294ff8f9ae4..9bd91cd615d5 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -294,7 +294,6 @@ void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
 			  enum netfs_sreq_ref_trace what);
 void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
 			  bool was_async, enum netfs_sreq_ref_trace what);
-void netfs_stats_show(struct seq_file *);
 ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
 				struct iov_iter *new,
 				iov_iter_extraction_t extraction_flags);