cifs: handle cases where a channel is closed

[ Upstream commit 0c51cc6f2cb0108e7d49805f6e089cd85caab279 ]

So far, SMB multichannel could only scale up, but not
scale down the number of channels. In this series of
patch, we now allow the client to deal with the case
of multichannel disabled on the server when the share
is mounted. With that change, we now need the ability
to scale down the channels.

This change allows the client to deal with cases of
missing channels more gracefully.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: 78e727e58e54 ("cifs: update iface_last_update on each query-and-update")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/smb/client/cifs_debug.c b/fs/smb/client/cifs_debug.c
index a2584ad8808a9f3680544c94e8a9a8f7e4a60842..3230ed7eaddec9b30bd8ffad90c303a1de5cc2e4 100644 (file)
--- a/fs/smb/client/cifs_debug.c
+++ b/fs/smb/client/cifs_debug.c
@@ -138,6 +138,11 @@ cifs_dump_channel(struct seq_file *m, int i, struct cifs_chan *chan)
 {
        struct TCP_Server_Info *server = chan->server;
 
+       if (!server) {
+               seq_printf(m, "\n\n\t\tChannel: %d DISABLED", i+1);
+               return;
+       }
+
        seq_printf(m, "\n\n\t\tChannel: %d ConnectionId: 0x%llx"
                   "\n\t\tNumber of credits: %d,%d,%d Dialect 0x%x"
                   "\n\t\tTCP status: %d Instance: %d"

diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index ec1e5e20a36be9980e6ae61b47710b1d8ce2eda4..e3ef8eee68d116c51a5c4825102c7319283db2c0 100644 (file)
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1060,6 +1060,7 @@ struct cifs_ses {
        spinlock_t chan_lock;
        /* ========= begin: protected by chan_lock ======== */
 #define CIFS_MAX_CHANNELS 16
+#define CIFS_INVAL_CHAN_INDEX (-1)
 #define CIFS_ALL_CHANNELS_SET(ses)     \
        ((1UL << (ses)->chan_count) - 1)
 #define CIFS_ALL_CHANS_GOOD(ses)               \

diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h
index c858feaf4f9264225b0604628aea1d137b5f63c4..0eb62ccd476fae3284adede50072e178542ea362 100644 (file)
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -622,7 +622,7 @@ bool is_server_using_iface(struct TCP_Server_Info *server,
 bool is_ses_using_iface(struct cifs_ses *ses, struct cifs_server_iface *iface);
 void cifs_ses_mark_for_reconnect(struct cifs_ses *ses);
 
-unsigned int
+int
 cifs_ses_get_chan_index(struct cifs_ses *ses,
                        struct TCP_Server_Info *server);
 void

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index b82f60d6f47ee149ce68af0ec8cd5e1021a1eeb8..a482afa3fa4247a1f4f8ee7792802a75a21371c5 100644 (file)
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -169,8 +169,12 @@ cifs_signal_cifsd_for_reconnect(struct TCP_Server_Info *server,
        list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
                spin_lock(&ses->chan_lock);
                for (i = 0; i < ses->chan_count; i++) {
+                       if (!ses->chans[i].server)
+                               continue;
+
                        spin_lock(&ses->chans[i].server->srv_lock);
-                       ses->chans[i].server->tcpStatus = CifsNeedReconnect;
+                       if (ses->chans[i].server->tcpStatus != CifsExiting)
+                               ses->chans[i].server->tcpStatus = CifsNeedReconnect;
                        spin_unlock(&ses->chans[i].server->srv_lock);
                }
                spin_unlock(&ses->chan_lock);

diff --git a/fs/smb/client/sess.c b/fs/smb/client/sess.c
index 80050e36f045125613b4809e0149d9aad0dfbb43..650a3ec9e6e52c48f1163048f24a08f8229ad112 100644 (file)
--- a/fs/smb/client/sess.c
+++ b/fs/smb/client/sess.c
@@ -69,7 +69,7 @@ bool is_ses_using_iface(struct cifs_ses *ses, struct cifs_server_iface *iface)
 
 /* channel helper functions. assumed that chan_lock is held by caller. */
 
-unsigned int
+int
 cifs_ses_get_chan_index(struct cifs_ses *ses,
                        struct TCP_Server_Info *server)
 {
@@ -85,14 +85,17 @@ cifs_ses_get_chan_index(struct cifs_ses *ses,
                cifs_dbg(VFS, "unable to get chan index for server: 0x%llx",
                         server->conn_id);
        WARN_ON(1);
-       return 0;
+       return CIFS_INVAL_CHAN_INDEX;
 }
 
 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);
+       int chan_index = cifs_ses_get_chan_index(ses, server);
+
+       if (chan_index == CIFS_INVAL_CHAN_INDEX)
+               return;
 
        ses->chans[chan_index].in_reconnect = true;
 }
@@ -102,6 +105,8 @@ 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);
+       if (chan_index == CIFS_INVAL_CHAN_INDEX)
+               return;
 
        ses->chans[chan_index].in_reconnect = false;
 }
@@ -111,6 +116,8 @@ cifs_chan_in_reconnect(struct cifs_ses *ses,
                          struct TCP_Server_Info *server)
 {
        unsigned int chan_index = cifs_ses_get_chan_index(ses, server);
+       if (chan_index == CIFS_INVAL_CHAN_INDEX)
+               return true;    /* err on the safer side */
 
        return CIFS_CHAN_IN_RECONNECT(ses, chan_index);
 }
@@ -120,6 +127,8 @@ cifs_chan_set_need_reconnect(struct cifs_ses *ses,
                             struct TCP_Server_Info *server)
 {
        unsigned int chan_index = cifs_ses_get_chan_index(ses, server);
+       if (chan_index == CIFS_INVAL_CHAN_INDEX)
+               return;
 
        set_bit(chan_index, &ses->chans_need_reconnect);
        cifs_dbg(FYI, "Set reconnect bitmask for chan %u; now 0x%lx\n",
@@ -131,6 +140,8 @@ cifs_chan_clear_need_reconnect(struct cifs_ses *ses,
                               struct TCP_Server_Info *server)
 {
        unsigned int chan_index = cifs_ses_get_chan_index(ses, server);
+       if (chan_index == CIFS_INVAL_CHAN_INDEX)
+               return;
 
        clear_bit(chan_index, &ses->chans_need_reconnect);
        cifs_dbg(FYI, "Cleared reconnect bitmask for chan %u; now 0x%lx\n",
@@ -142,6 +153,8 @@ cifs_chan_needs_reconnect(struct cifs_ses *ses,
                          struct TCP_Server_Info *server)
 {
        unsigned int chan_index = cifs_ses_get_chan_index(ses, server);
+       if (chan_index == CIFS_INVAL_CHAN_INDEX)
+               return true;    /* err on the safer side */
 
        return CIFS_CHAN_NEEDS_RECONNECT(ses, chan_index);
 }
@@ -151,6 +164,8 @@ cifs_chan_is_iface_active(struct cifs_ses *ses,
                          struct TCP_Server_Info *server)
 {
        unsigned int chan_index = cifs_ses_get_chan_index(ses, server);
+       if (chan_index == CIFS_INVAL_CHAN_INDEX)
+               return true;    /* err on the safer side */
 
        return ses->chans[chan_index].iface &&
                ses->chans[chan_index].iface->is_active;
@@ -293,7 +308,7 @@ cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)
 
        spin_lock(&ses->chan_lock);
        chan_index = cifs_ses_get_chan_index(ses, server);
-       if (!chan_index) {
+       if (chan_index == CIFS_INVAL_CHAN_INDEX) {
                spin_unlock(&ses->chan_lock);
                return 0;
        }
@@ -403,6 +418,11 @@ cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)
 
        spin_lock(&ses->chan_lock);
        chan_index = cifs_ses_get_chan_index(ses, server);
+       if (chan_index == CIFS_INVAL_CHAN_INDEX) {
+               spin_unlock(&ses->chan_lock);
+               return 0;
+       }
+
        ses->chans[chan_index].iface = iface;
 
        /* No iface is found. if secondary chan, drop connection */

diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c
index a136fc4cc2b5fbc7fed626e7f0f5c51e491d56ac..5a3ca62d2f07f72584392975221cbc9b12276fe8 100644 (file)
--- a/fs/smb/client/smb2transport.c
+++ b/fs/smb/client/smb2transport.c
@@ -413,7 +413,13 @@ generate_smb3signingkey(struct cifs_ses *ses,
                      ses->ses_status == SES_GOOD);
 
        chan_index = cifs_ses_get_chan_index(ses, server);
-       /* TODO: introduce ref counting for channels when the can be freed */
+       if (chan_index == CIFS_INVAL_CHAN_INDEX) {
+               spin_unlock(&ses->chan_lock);
+               spin_unlock(&ses->ses_lock);
+
+               return -EINVAL;
+       }
+
        spin_unlock(&ses->chan_lock);
        spin_unlock(&ses->ses_lock);