[PATCH 16/17] fsinfo: Add example support for Ext4 [ver #17]

David Howells
2020-02-21T18:04:05Z

Add the ability to list some Ext4 volume timestamps as an example.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-ext4@vger.kernel.org
---

fs/ext4/Makefile | 1 +
fs/ext4/ext4.h | 6 ++++++
fs/ext4/fsinfo.c | 45 +++++++++++++++++++++++++++++++++++++++++++
fs/ext4/super.c | 3 +++
include/uapi/linux/fsinfo.h | 16 +++++++++++++++
samples/vfs/test-fsinfo.c | 35 +++++++++++++++++++++++++++++++++
6 files changed, 106 insertions(+)
create mode 100644 fs/ext4/fsinfo.c

diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 4ccb3c9189d8..71d5b460c7c7 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -16,3 +16,4 @@ ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o
ext4-inode-test-objs += inode-test.o
obj-$(CONFIG_EXT4_KUNIT_TESTS) += ext4-inode-test.o
ext4-$(CONFIG_FS_VERITY) += verity.o
+ext4-$(CONFIG_FSINFO) += fsinfo.o
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9a2ee2428ecc..461968a87cd6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -42,6 +42,7 @@

#include <linux/fscrypt.h>
#include <linux/fsverity.h>
+#include <linux/fsinfo.h>

#include <linux/compiler.h>

@@ -3166,6 +3167,11 @@ extern const struct inode_operations ext4_file_inode_operations;
extern const struct file_operations ext4_file_operations;
extern loff_t ext4_llseek(struct file *file, loff_t offset, int origin);

+/* fsinfo.c */
+#ifdef CONFIG_FSINFO
+extern int ext4_fsinfo(struct path *path, struct fsinfo_context *ctx);
+#endif
+
/* inline.c */
extern int ext4_get_max_inline_size(struct inode *inode);
extern int ext4_find_inline_data_nolock(struct inode *inode);
diff --git a/fs/ext4/fsinfo.c b/fs/ext4/fsinfo.c
new file mode 100644
index 000000000000..785f82a74dc9
--- /dev/null
+++ b/fs/ext4/fsinfo.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Filesystem information for ext4
+ *
+ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/mount.h>
+#include "ext4.h"
+
+static int ext4_fsinfo_get_volume_name(struct path *path, struct fsinfo_context *ctx)
+{
+ const struct ext4_sb_info *sbi = EXT4_SB(path->mnt->mnt_sb);
+ const struct ext4_super_block *es = sbi->s_es;
+
+ memcpy(ctx->buffer, es->s_volume_name, sizeof(es->s_volume_name));
+ return strlen(ctx->buffer);
+}
+
+static int ext4_fsinfo_get_timestamps(struct path *path, struct fsinfo_context *ctx)
+{
+ const struct ext4_sb_info *sbi = EXT4_SB(path->mnt->mnt_sb);
+ const struct ext4_super_block *es = sbi->s_es;
+ struct fsinfo_ext4_timestamps *ts = ctx->buffer;
+
+#define Z(R,S) R = S | (((u64)S##_hi) << 32)
+ Z(ts->mkfs_time, es->s_mkfs_time);
+ Z(ts->mount_time, es->s_mtime);
+ Z(ts->write_time, es->s_wtime);
+ Z(ts->last_check_time, es->s_lastcheck);
+ Z(ts->first_error_time, es->s_first_error_time);
+ Z(ts->last_error_time, es->s_last_error_time);
+ return sizeof(*ts);
+}
+
+static const struct fsinfo_attribute ext4_fsinfo_attributes[] = {
+ FSINFO_STRING (FSINFO_ATTR_VOLUME_NAME, ext4_fsinfo_get_volume_name),
+ FSINFO_VSTRUCT (FSINFO_ATTR_EXT4_TIMESTAMPS, ext4_fsinfo_get_timestamps),
+ {}
+};
+
+int ext4_fsinfo(struct path *path, struct fsinfo_context *ctx)
+{
+ return fsinfo_get_attribute(path, ctx, ext4_fsinfo_attributes);
+}
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 8434217549b3..02b4df073c4b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1477,6 +1477,9 @@ static const struct super_operations ext4_sops = {
.freeze_fs = ext4_freeze,
.unfreeze_fs = ext4_unfreeze,
.statfs = ext4_statfs,
+#ifdef CONFIG_FSINFO
+ .fsinfo = ext4_fsinfo,
+#endif
.remount_fs = ext4_remount,
.show_options = ext4_show_options,
#ifdef CONFIG_QUOTA
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index a587b6f9847c..6a8a7a8e4910 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -37,6 +37,8 @@
#define FSINFO_ATTR_AFS_SERVER_NAME 0x301 /* Name of the Nth server (string) */
#define FSINFO_ATTR_AFS_SERVER_ADDRESSES 0x302 /* List of addresses of the Nth server */

+#define FSINFO_ATTR_EXT4_TIMESTAMPS 0x400 /* Ext4 superblock timestamps */
+
/*
* Optional fsinfo() parameter structure.
*
@@ -313,4 +315,18 @@ struct fsinfo_afs_server_address {

#define FSINFO_ATTR_AFS_SERVER_ADDRESSES__STRUCT struct fsinfo_afs_server_address

+/*
+ * Information struct for fsinfo(FSINFO_ATTR_EXT4_TIMESTAMPS).
+ */
+struct fsinfo_ext4_timestamps {
+ __u64 mkfs_time;
+ __u64 mount_time;
+ __u64 write_time;
+ __u64 last_check_time;
+ __u64 first_error_time;
+ __u64 last_error_time;
+};
+
+#define FSINFO_ATTR_EXT4_TIMESTAMPS__STRUCT struct fsinfo_ext4_timestamps
+
#endif /* _UAPI_LINUX_FSINFO_H */
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index f0dc90fdd49d..df8d2449fc22 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -357,6 +357,40 @@ static void dump_afs_fsinfo_server_address(void *reply, unsigned int size)
printf("family=%u\n", ss->ss_family);
}

+static char *dump_ext4_time(char *buffer, time_t tim)
+{
+ struct tm tm;
+ int len;
+
+ if (tim == 0)
+ return "-";
+
+ if (!localtime_r(&tim, &tm)) {
+ perror("localtime_r");
+ exit(1);
+ }
+ len = strftime(buffer, 100, "%F %T", &tm);
+ if (len == 0) {
+ perror("strftime");
+ exit(1);
+ }
+ return buffer;
+}
+
+static void dump_ext4_fsinfo_timestamps(void *reply, unsigned int size)
+{
+ struct fsinfo_ext4_timestamps *r = reply;
+ char buffer[100];
+
+ printf("\n");
+ printf("\tmkfs : %s\n", dump_ext4_time(buffer, r->mkfs_time));
+ printf("\tmount : %s\n", dump_ext4_time(buffer, r->mount_time));
+ printf("\twrite : %s\n", dump_ext4_time(buffer, r->write_time));
+ printf("\tfsck : %s\n", dump_ext4_time(buffer, r->last_check_time));
+ printf("\t1st-err : %s\n", dump_ext4_time(buffer, r->first_error_time));
+ printf("\tlast-err: %s\n", dump_ext4_time(buffer, r->last_error_time));
+}
+
static void dump_string(void *reply, unsigned int size)
{
char *s = reply, *p;
@@ -433,6 +467,7 @@ static const struct fsinfo_attribute fsinfo_attributes[] = {
FSINFO_STRING (FSINFO_ATTR_AFS_CELL_NAME, afs_cell_name),
FSINFO_STRING (FSINFO_ATTR_AFS_SERVER_NAME, afs_server_name),
FSINFO_LIST_N (FSINFO_ATTR_AFS_SERVER_ADDRESSES, afs_fsinfo_server_address),
+ FSINFO_VSTRUCT (FSINFO_ATTR_EXT4_TIMESTAMPS, ext4_fsinfo_timestamps),
{}
};