From: David Howells <dhowells@redhat.com>
To: viro@zeniv.linux.org.uk
Cc: dhowells@redhat.com, raven@themaw.net,
linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
linux-block@vger.kernel.org, keyrings@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 09/13] fsinfo: Export superblock notification counter [ver #4]
Date: Fri, 07 Jun 2019 15:18:49 +0100 [thread overview]
Message-ID: <155991712904.15579.2181300108455141366.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <155991702981.15579.6007568669839441045.stgit@warthog.procyon.org.uk>
Provide an fsinfo attribute to export the superblock notification counter
so that it can be polled in the case of a notification buffer overrun.
This is accessed with:
struct fsinfo_params params = {
.request = FSINFO_ATTR_SB_NOTIFICATIONS,
};
and returns a structure that looks like:
struct fsinfo_sb_notifications {
__u64 watch_id;
__u32 notify_counter;
__u32 __reserved[1];
};
Where watch_id is a number uniquely identifying the superblock in
notification records and notify_counter is incremented for each
superblock notification posted.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/fsinfo.c | 12 ++++++++++++
fs/super.c | 1 +
include/linux/fs.h | 1 +
include/uapi/linux/fsinfo.h | 10 ++++++++++
include/uapi/linux/watch_queue.h | 2 +-
samples/vfs/test-fsinfo.c | 13 +++++++++++++
6 files changed, 38 insertions(+), 1 deletion(-)
diff --git a/fs/fsinfo.c b/fs/fsinfo.c
index 3ec64d3cba08..1456e26d2f7c 100644
--- a/fs/fsinfo.c
+++ b/fs/fsinfo.c
@@ -284,6 +284,16 @@ static int fsinfo_generic_param_enum(struct file_system_type *f,
return sizeof(*p);
}
+static int fsinfo_generic_sb_notifications(struct path *path,
+ struct fsinfo_sb_notifications *p)
+{
+ struct super_block *sb = path->dentry->d_sb;
+
+ p->watch_id = sb->s_unique_id;
+ p->notify_counter = atomic_read(&sb->s_notify_counter);
+ return sizeof(*p);
+}
+
static void fsinfo_insert_sb_flag_parameters(struct path *path,
struct fsinfo_kparams *params)
{
@@ -331,6 +341,7 @@ int generic_fsinfo(struct path *path, struct fsinfo_kparams *params)
case _genp(MOUNT_DEVNAME, mount_devname);
case _genp(MOUNT_CHILDREN, mount_children);
case _genp(MOUNT_SUBMOUNT, mount_submount);
+ case _gen(SB_NOTIFICATIONS, sb_notifications);
default:
return -EOPNOTSUPP;
}
@@ -606,6 +617,7 @@ static const struct fsinfo_attr_info fsinfo_buffer_info[FSINFO_ATTR__NR] = {
FSINFO_STRING_N (SERVER_NAME, server_name),
FSINFO_STRUCT_NM (SERVER_ADDRESS, server_address),
FSINFO_STRING (CELL_NAME, cell_name),
+ FSINFO_STRUCT (SB_NOTIFICATIONS, sb_notifications),
};
/**
diff --git a/fs/super.c b/fs/super.c
index 5bfe409a4fbe..b9bd4a849b69 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1823,6 +1823,7 @@ EXPORT_SYMBOL(thaw_super);
*/
void post_sb_notification(struct super_block *s, struct superblock_notification *n)
{
+ atomic_inc(&s->s_notify_counter);
post_watch_notification(s->s_watchers, &n->watch, current_cred(),
s->s_unique_id);
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 02ba4bfb9cc3..06e272a25ed7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1536,6 +1536,7 @@ struct super_block {
#ifdef CONFIG_SB_NOTIFICATIONS
struct watch_list *s_watchers;
#endif
+ atomic_t s_notify_counter;
} __randomize_layout;
/* Helper functions so that in most cases filesystems will
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
index bb38f9c41772..31e9354170c5 100644
--- a/include/uapi/linux/fsinfo.h
+++ b/include/uapi/linux/fsinfo.h
@@ -39,6 +39,7 @@ enum fsinfo_attribute {
FSINFO_ATTR_SERVER_NAME = 21, /* Name of the Nth server (string) */
FSINFO_ATTR_SERVER_ADDRESS = 22, /* Mth address of the Nth server */
FSINFO_ATTR_CELL_NAME = 23, /* Cell name (string) */
+ FSINFO_ATTR_SB_NOTIFICATIONS = 24, /* sb_notify() information */
FSINFO_ATTR__NR
};
@@ -308,4 +309,13 @@ struct fsinfo_server_address {
struct __kernel_sockaddr_storage address;
};
+/*
+ * Information struct for fsinfo(FSINFO_ATTR_SB_NOTIFICATIONS).
+ */
+struct fsinfo_sb_notifications {
+ __u64 watch_id; /* Watch ID for superblock. */
+ __u32 notify_counter; /* Number of notifications. */
+ __u32 __reserved[1];
+};
+
#endif /* _UAPI_LINUX_FSINFO_H */
diff --git a/include/uapi/linux/watch_queue.h b/include/uapi/linux/watch_queue.h
index 66b0da7cf888..aeffcfd7a742 100644
--- a/include/uapi/linux/watch_queue.h
+++ b/include/uapi/linux/watch_queue.h
@@ -146,7 +146,7 @@ enum superblock_notification_type {
*/
struct superblock_notification {
struct watch_notification watch; /* WATCH_TYPE_SB_NOTIFY */
- __u64 sb_id; /* 64-bit superblock ID [fsinfo_ids::f_sb_id] */
+ __u64 sb_id; /* 64-bit superblock ID [fsinfo_sb_notifications::watch_id] */
};
struct superblock_error_notification {
diff --git a/samples/vfs/test-fsinfo.c b/samples/vfs/test-fsinfo.c
index af29da74559e..0f8f9ded0925 100644
--- a/samples/vfs/test-fsinfo.c
+++ b/samples/vfs/test-fsinfo.c
@@ -90,6 +90,7 @@ static const struct fsinfo_attr_info fsinfo_buffer_info[FSINFO_ATTR__NR] = {
FSINFO_STRING_N (SERVER_NAME, server_name),
FSINFO_STRUCT_NM (SERVER_ADDRESS, server_address),
FSINFO_STRING (CELL_NAME, cell_name),
+ FSINFO_STRUCT (SB_NOTIFICATIONS, sb_notifications),
};
#define FSINFO_NAME(X,Y) [FSINFO_ATTR_##X] = #Y
@@ -118,6 +119,7 @@ static const char *fsinfo_attr_names[FSINFO_ATTR__NR] = {
FSINFO_NAME (SERVER_NAME, server_name),
FSINFO_NAME (SERVER_ADDRESS, server_address),
FSINFO_NAME (CELL_NAME, cell_name),
+ FSINFO_NAME (SB_NOTIFICATIONS, sb_notifications),
};
union reply {
@@ -133,6 +135,7 @@ union reply {
struct fsinfo_mount_info mount_info;
struct fsinfo_mount_child mount_children[1];
struct fsinfo_server_address srv_addr;
+ struct fsinfo_sb_notifications sb_notifications;
};
static void dump_hex(unsigned int *data, int from, int to)
@@ -377,6 +380,15 @@ static void dump_attr_MOUNT_CHILDREN(union reply *r, int size)
printf("\t[%u] %8x %8x\n", i++, f->mnt_id, f->notify_counter);
}
+static void dump_attr_SB_NOTIFICATIONS(union reply *r, int size)
+{
+ struct fsinfo_sb_notifications *f = &r->sb_notifications;
+
+ printf("\n");
+ printf("\twatch_id: %llx\n", (unsigned long long)f->watch_id);
+ printf("\tnotifs : %llx\n", (unsigned long long)f->notify_counter);
+}
+
/*
*
*/
@@ -395,6 +407,7 @@ static const dumper_t fsinfo_attr_dumper[FSINFO_ATTR__NR] = {
FSINFO_DUMPER(MOUNT_INFO),
FSINFO_DUMPER(MOUNT_CHILDREN),
FSINFO_DUMPER(SERVER_ADDRESS),
+ FSINFO_DUMPER(SB_NOTIFICATIONS),
};
static void dump_fsinfo(enum fsinfo_attribute attr,
next prev parent reply other threads:[~2019-06-07 14:18 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-07 14:17 [RFC][PATCH 00/13] Mount, FS, Block and Keyrings notifications [ver #4] David Howells
2019-06-07 14:17 ` [PATCH 01/13] security: Override creds in __fput() with last fputter's creds " David Howells
2019-06-07 14:17 ` [PATCH 02/13] uapi: General notification ring definitions " David Howells
2019-06-07 15:12 ` Darrick J. Wong
2019-06-07 15:30 ` David Howells
2019-06-07 15:51 ` David Howells
2019-06-09 4:35 ` Randy Dunlap
2019-06-13 13:34 ` David Howells
2019-06-13 14:49 ` Randy Dunlap
2019-06-07 14:17 ` [PATCH 03/13] security: Add hooks to rule on setting a watch " David Howells
2019-06-07 14:17 ` [PATCH 04/13] security: Add a hook for the point of notification insertion " David Howells
2019-06-07 14:18 ` [PATCH 05/13] General notification queue with user mmap()'able ring buffer " David Howells
2019-06-07 14:18 ` [PATCH 06/13] keys: Add a notification facility " David Howells
2019-06-10 17:11 ` Jonathan Corbet
2019-06-10 17:47 ` David Howells
2019-06-07 14:18 ` [PATCH 07/13] vfs: Add a mount-notification " David Howells
2019-06-07 14:18 ` [PATCH 08/13] vfs: Add superblock notifications " David Howells
2019-06-07 14:18 ` David Howells [this message]
2019-06-07 14:18 ` [PATCH 10/13] Add a general, global device notification watch list " David Howells
2019-06-07 14:19 ` [PATCH 11/13] block: Add block layer notifications " David Howells
2019-06-07 14:19 ` [PATCH 12/13] usb: Add USB subsystem " David Howells
2019-06-07 14:19 ` [PATCH 13/13] Add sample notification program " David Howells
2019-06-10 15:21 ` [RFC][PATCH 00/13] Mount, FS, Block and Keyrings notifications " Stephen Smalley
2019-06-10 16:33 ` Casey Schaufler
2019-06-10 16:42 ` Andy Lutomirski
2019-06-10 18:01 ` Casey Schaufler
2019-06-10 18:22 ` Andy Lutomirski
2019-06-10 19:33 ` Casey Schaufler
2019-06-10 19:53 ` Andy Lutomirski
2019-06-10 21:25 ` Casey Schaufler
2019-06-11 0:13 ` Andy Lutomirski
2019-06-11 14:32 ` Stephen Smalley
2019-06-12 8:55 ` David Howells
2019-06-10 22:07 ` David Howells
2019-06-11 14:21 ` What do LSMs *actually* need for checks on notifications? David Howells
2019-06-11 15:57 ` Stephen Smalley
2019-06-11 16:22 ` Casey Schaufler
2019-06-12 11:43 ` David Howells
2019-06-13 18:46 ` Stephen Smalley
2019-06-12 17:41 ` David Howells
2019-06-12 18:14 ` Casey Schaufler
2019-06-12 18:36 ` David Howells
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