From: Shyam Prasad N <sprasad@microsoft.com>
Date: Fri, 8 Apr 2022 13:31:37 +0000
Subject: [PATCH] cifs: avoid parallel session setups on same channel
Git-commit: 5752bf645f9dd7db600651f726eb04a97c9f597f
References: bsc#1193629
Patch-mainline: v5.19-rc1
After allowing channels to reconnect in parallel, it now
becomes important to take care that multiple processes do not
call negotiate/session setup in parallel on the same channel.
This change avoids that by marking a channel as "in_reconnect".
During session setup if the channel in question has this flag
set, we return immediately.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
fs/cifs/cifs_debug.c | 4 ++++
fs/cifs/cifsglob.h | 5 +++++
fs/cifs/cifsproto.h | 9 +++++++++
fs/cifs/connect.c | 27 ++++++++++++++++++++-------
fs/cifs/sess.c | 27 +++++++++++++++++++++++++++
5 files changed, 65 insertions(+), 7 deletions(-)
diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index c098735d41c6..1dd995efd5b8 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -419,6 +419,8 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
spin_lock(&ses->chan_lock);
if (CIFS_CHAN_NEEDS_RECONNECT(ses, 0))
seq_puts(m, "\tPrimary channel: DISCONNECTED ");
+ if (CIFS_CHAN_IN_RECONNECT(ses, 0))
+ seq_puts(m, "\t[RECONNECTING] ");
if (ses->chan_count > 1) {
seq_printf(m, "\n\n\tExtra Channels: %zu ",
@@ -427,6 +429,8 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
cifs_dump_channel(m, j, &ses->chans[j]);
if (CIFS_CHAN_NEEDS_RECONNECT(ses, j))
seq_puts(m, "\tDISCONNECTED ");
+ if (CIFS_CHAN_IN_RECONNECT(ses, j))
+ seq_puts(m, "\t[RECONNECTING] ");
}
}
spin_unlock(&ses->chan_lock);
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 711cf51ac14f..8880a26f234f 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -922,6 +922,7 @@ struct cifs_server_iface {
};
struct cifs_chan {
+ unsigned int in_reconnect : 1; /* if session setup in progress for this channel */
struct TCP_Server_Info *server;
__u8 signkey[SMB3_SIGN_KEY_SIZE];
};
@@ -984,12 +985,16 @@ struct cifs_ses {
#define CIFS_MAX_CHANNELS 16
#define CIFS_ALL_CHANNELS_SET(ses) \
((1UL << (ses)->chan_count) - 1)
+#define CIFS_ALL_CHANS_GOOD(ses) \
+ (!(ses)->chans_need_reconnect)
#define CIFS_ALL_CHANS_NEED_RECONNECT(ses) \
((ses)->chans_need_reconnect == CIFS_ALL_CHANNELS_SET(ses))
#define CIFS_SET_ALL_CHANS_NEED_RECONNECT(ses) \
((ses)->chans_need_reconnect = CIFS_ALL_CHANNELS_SET(ses))
#define CIFS_CHAN_NEEDS_RECONNECT(ses, index) \
test_bit((index), &(ses)->chans_need_reconnect)
+#define CIFS_CHAN_IN_RECONNECT(ses, index) \
+ ((ses)->chans[(index)].in_reconnect)
struct cifs_chan chans[CIFS_MAX_CHANNELS];
size_t chan_count;
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 0df3b24a0bf4..3b7366ec03c7 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -619,6 +619,15 @@ unsigned int
cifs_ses_get_chan_index(struct cifs_ses *ses,
struct TCP_Server_Info *server);
void
+cifs_chan_set_in_reconnect(struct cifs_ses *ses,
+ struct TCP_Server_Info *server);
+void
+cifs_chan_clear_in_reconnect(struct cifs_ses *ses,
+ struct TCP_Server_Info *server);
+bool
+cifs_chan_in_reconnect(struct cifs_ses *ses,
+ struct TCP_Server_Info *server);
+void
cifs_chan_set_need_reconnect(struct cifs_ses *ses,
struct TCP_Server_Info *server);
void
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index df4bcc581559..199b076f7a64 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3995,17 +3995,27 @@ cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
int rc = -ENOSYS;
bool is_binding = false;
- /* only send once per connect */
- spin_lock(&ses->chan_lock);
- is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
- spin_unlock(&ses->chan_lock);
spin_lock(&cifs_tcp_ses_lock);
- if (ses->ses_status == SES_EXITING) {
+ if (ses->ses_status != SES_GOOD &&
+ ses->ses_status != SES_NEW &&
+ ses->ses_status != SES_NEED_RECON) {
spin_unlock(&cifs_tcp_ses_lock);
return 0;
}
+ /* only send once per connect */
+ spin_lock(&ses->chan_lock);
+ if (CIFS_ALL_CHANS_GOOD(ses) ||
+ cifs_chan_in_reconnect(ses, server)) {
+ spin_unlock(&ses->chan_lock);
+ spin_unlock(&cifs_tcp_ses_lock);
+ return 0;
+ }
+ is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
+ cifs_chan_set_in_reconnect(ses, server);
+ spin_unlock(&ses->chan_lock);
+
if (!is_binding)
ses->ses_status = SES_IN_SETUP;
spin_unlock(&cifs_tcp_ses_lock);
@@ -4035,16 +4045,19 @@ cifs_setup_session(const unsigned int xid, struct cifs_ses *ses,
spin_lock(&cifs_tcp_ses_lock);
if (ses->ses_status == SES_IN_SETUP)
ses->ses_status = SES_NEED_RECON;
+ spin_lock(&ses->chan_lock);
+ cifs_chan_clear_in_reconnect(ses, server);
+ spin_unlock(&ses->chan_lock);
spin_unlock(&cifs_tcp_ses_lock);
} else {
spin_lock(&cifs_tcp_ses_lock);
if (ses->ses_status == SES_IN_SETUP)
ses->ses_status = SES_GOOD;
- spin_unlock(&cifs_tcp_ses_lock);
-
spin_lock(&ses->chan_lock);
+ cifs_chan_clear_in_reconnect(ses, server);
cifs_chan_clear_need_reconnect(ses, server);
spin_unlock(&ses->chan_lock);
+ spin_unlock(&cifs_tcp_ses_lock);
}
return rc;
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 32f478c7a66d..7c453f8701eb 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -85,6 +85,33 @@ cifs_ses_get_chan_index(struct cifs_ses *ses,
return 0;
}
+void
+cifs_chan_set_in_reconnect(struct cifs_ses *ses,
+ struct TCP_Server_Info *server)
+{
+ unsigned int chan_index = cifs_ses_get_chan_index(ses, server);
+
+ ses->chans[chan_index].in_reconnect = true;
+}
+
+void
+cifs_chan_clear_in_reconnect(struct cifs_ses *ses,
+ struct TCP_Server_Info *server)
+{
+ unsigned int chan_index = cifs_ses_get_chan_index(ses, server);
+
+ ses->chans[chan_index].in_reconnect = false;
+}
+
+bool
+cifs_chan_in_reconnect(struct cifs_ses *ses,
+ struct TCP_Server_Info *server)
+{
+ unsigned int chan_index = cifs_ses_get_chan_index(ses, server);
+
+ return CIFS_CHAN_IN_RECONNECT(ses, chan_index);
+}
+
void
cifs_chan_set_need_reconnect(struct cifs_ses *ses,
struct TCP_Server_Info *server)
--
2.36.1