[PATCH v3 06/11] cifs: Set witness notification handler for messages from userspace daemon

Samuel Cabrero
2020-10-30T11:53:03Z

+ Set a handler for the witness notification messages received from the
userspace daemon.

+ Handle the resource state change notification. When the resource
becomes unavailable or available set the tcp status to
CifsNeedReconnect for all channels.

Signed-off-by: Samuel Cabrero <scabrero@suse.de>
---
fs/cifs/cifs_swn.c | 86 ++++++++++++++++++++++++++
fs/cifs/cifs_swn.h | 4 ++
fs/cifs/netlink.c | 9 +++
include/uapi/linux/cifs/cifs_netlink.h | 17 +++++
4 files changed, 116 insertions(+)

diff --git a/fs/cifs/cifs_swn.c b/fs/cifs/cifs_swn.c
index c7d70e28341e..501d84893262 100644
--- a/fs/cifs/cifs_swn.c
+++ b/fs/cifs/cifs_swn.c
@@ -379,6 +379,92 @@ static void cifs_put_swn_reg(struct cifs_swn_reg *swnreg)
mutex_unlock(&cifs_swnreg_idr_mutex);
}

+static int cifs_swn_resource_state_changed(struct cifs_swn_reg *swnreg, const char *name, int state)
+{
+ int i;
+
+ switch (state) {
+ case CIFS_SWN_RESOURCE_STATE_UNAVAILABLE:
+ cifs_dbg(FYI, "%s: resource name '%s' become unavailable\n", __func__, name);
+ for (i = 0; i < swnreg->tcon->ses->chan_count; i++) {
+ spin_lock(&GlobalMid_Lock);
+ if (swnreg->tcon->ses->chans[i].server->tcpStatus != CifsExiting)
+ swnreg->tcon->ses->chans[i].server->tcpStatus = CifsNeedReconnect;
+ spin_unlock(&GlobalMid_Lock);
+ }
+ break;
+ case CIFS_SWN_RESOURCE_STATE_AVAILABLE:
+ cifs_dbg(FYI, "%s: resource name '%s' become available\n", __func__, name);
+ for (i = 0; i < swnreg->tcon->ses->chan_count; i++) {
+ spin_lock(&GlobalMid_Lock);
+ if (swnreg->tcon->ses->chans[i].server->tcpStatus != CifsExiting)
+ swnreg->tcon->ses->chans[i].server->tcpStatus = CifsNeedReconnect;
+ spin_unlock(&GlobalMid_Lock);
+ }
+ break;
+ case CIFS_SWN_RESOURCE_STATE_UNKNOWN:
+ cifs_dbg(FYI, "%s: resource name '%s' changed to unknown state\n", __func__, name);
+ break;
+ }
+ return 0;
+}
+
+int cifs_swn_notify(struct sk_buff *skb, struct genl_info *info)
+{
+ struct cifs_swn_reg *swnreg;
+ char name[256];
+ int type;
+
+ if (info->attrs[CIFS_GENL_ATTR_SWN_REGISTRATION_ID]) {
+ int swnreg_id;
+
+ swnreg_id = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_REGISTRATION_ID]);
+ mutex_lock(&cifs_swnreg_idr_mutex);
+ swnreg = idr_find(&cifs_swnreg_idr, swnreg_id);
+ mutex_unlock(&cifs_swnreg_idr_mutex);
+ if (swnreg == NULL) {
+ cifs_dbg(FYI, "%s: registration id %d not found\n", __func__, swnreg_id);
+ return -EINVAL;
+ }
+ } else {
+ cifs_dbg(FYI, "%s: missing registration id attribute\n", __func__);
+ return -EINVAL;
+ }
+
+ if (info->attrs[CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE]) {
+ type = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE]);
+ } else {
+ cifs_dbg(FYI, "%s: missing notification type attribute\n", __func__);
+ return -EINVAL;
+ }
+
+ switch (type) {
+ case CIFS_SWN_NOTIFICATION_RESOURCE_CHANGE: {
+ int state;
+
+ if (info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_NAME]) {
+ nla_strlcpy(name, info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_NAME],
+ sizeof(name));
+ } else {
+ cifs_dbg(FYI, "%s: missing resource name attribute\n", __func__);
+ return -EINVAL;
+ }
+ if (info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_STATE]) {
+ state = nla_get_u32(info->attrs[CIFS_GENL_ATTR_SWN_RESOURCE_STATE]);
+ } else {
+ cifs_dbg(FYI, "%s: missing resource state attribute\n", __func__);
+ return -EINVAL;
+ }
+ return cifs_swn_resource_state_changed(swnreg, name, state);
+ }
+ default:
+ cifs_dbg(FYI, "%s: unknown notification type %d\n", __func__, type);
+ break;
+ }
+
+ return 0;
+}
+
int cifs_swn_register(struct cifs_tcon *tcon)
{
struct cifs_swn_reg *swnreg;
diff --git a/fs/cifs/cifs_swn.h b/fs/cifs/cifs_swn.h
index 69c7bd1035da..7ef9ecedbd05 100644
--- a/fs/cifs/cifs_swn.h
+++ b/fs/cifs/cifs_swn.h
@@ -9,9 +9,13 @@
#define _CIFS_SWN_H

struct cifs_tcon;
+struct sk_buff;
+struct genl_info;

extern int cifs_swn_register(struct cifs_tcon *tcon);

extern int cifs_swn_unregister(struct cifs_tcon *tcon);

+extern int cifs_swn_notify(struct sk_buff *skb, struct genl_info *info);
+
#endif /* _CIFS_SWN_H */
diff --git a/fs/cifs/netlink.c b/fs/cifs/netlink.c
index 83008a56def5..5aaabe4cc0a7 100644
--- a/fs/cifs/netlink.c
+++ b/fs/cifs/netlink.c
@@ -11,6 +11,7 @@
#include "netlink.h"
#include "cifsglob.h"
#include "cifs_debug.h"
+#include "cifs_swn.h"

static const struct nla_policy cifs_genl_policy[CIFS_GENL_ATTR_MAX + 1] = {
[CIFS_GENL_ATTR_SWN_REGISTRATION_ID] = { .type = NLA_U32 },
@@ -24,9 +25,17 @@ static const struct nla_policy cifs_genl_policy[CIFS_GENL_ATTR_MAX + 1] = {
[CIFS_GENL_ATTR_SWN_USER_NAME] = { .type = NLA_STRING },
[CIFS_GENL_ATTR_SWN_PASSWORD] = { .type = NLA_STRING },
[CIFS_GENL_ATTR_SWN_DOMAIN_NAME] = { .type = NLA_STRING },
+ [CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE] = { .type = NLA_U32 },
+ [CIFS_GENL_ATTR_SWN_RESOURCE_STATE] = { .type = NLA_U32 },
+ [CIFS_GENL_ATTR_SWN_RESOURCE_NAME] = { .type = NLA_STRING},
};

static struct genl_ops cifs_genl_ops[] = {
+ {
+ .cmd = CIFS_GENL_CMD_SWN_NOTIFY,
+ .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+ .doit = cifs_swn_notify,
+ },
};

static const struct genl_multicast_group cifs_genl_mcgrps[] = {
diff --git a/include/uapi/linux/cifs/cifs_netlink.h b/include/uapi/linux/cifs/cifs_netlink.h
index 5662e2774513..da3107582f49 100644
--- a/include/uapi/linux/cifs/cifs_netlink.h
+++ b/include/uapi/linux/cifs/cifs_netlink.h
@@ -31,6 +31,9 @@ enum cifs_genl_attributes {
CIFS_GENL_ATTR_SWN_USER_NAME,
CIFS_GENL_ATTR_SWN_PASSWORD,
CIFS_GENL_ATTR_SWN_DOMAIN_NAME,
+ CIFS_GENL_ATTR_SWN_NOTIFICATION_TYPE,
+ CIFS_GENL_ATTR_SWN_RESOURCE_STATE,
+ CIFS_GENL_ATTR_SWN_RESOURCE_NAME,
__CIFS_GENL_ATTR_MAX,
};
#define CIFS_GENL_ATTR_MAX (__CIFS_GENL_ATTR_MAX - 1)
@@ -39,8 +42,22 @@ enum cifs_genl_commands {
CIFS_GENL_CMD_UNSPEC,
CIFS_GENL_CMD_SWN_REGISTER,
CIFS_GENL_CMD_SWN_UNREGISTER,
+ CIFS_GENL_CMD_SWN_NOTIFY,
__CIFS_GENL_CMD_MAX
};
#define CIFS_GENL_CMD_MAX (__CIFS_GENL_CMD_MAX - 1)

+enum cifs_swn_notification_type {
+ CIFS_SWN_NOTIFICATION_RESOURCE_CHANGE = 0x01,
+ CIFS_SWN_NOTIFICATION_CLIENT_MOVE = 0x02,
+ CIFS_SWN_NOTIFICATION_SHARE_MOVE = 0x03,
+ CIFS_SWN_NOTIFICATION_IP_CHANGE = 0x04,
+};
+
+enum cifs_swn_resource_state {
+ CIFS_SWN_RESOURCE_STATE_UNKNOWN = 0x00,
+ CIFS_SWN_RESOURCE_STATE_AVAILABLE = 0x01,
+ CIFS_SWN_RESOURCE_STATE_UNAVAILABLE = 0xFF
+};
+
#endif /* _UAPILINUX_CIFS_NETLINK_H */
--
2.29.0