cifs: handle cases where a channel is closed

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>

diff --git a/fs/smb/client/cifs_debug.c b/fs/smb/client/cifs_debug.c
index 0d09bc3ea283fa0d3bce689f43aa5550ed5fc6ff..772d4226957f94b1af313fb4dd9d47ad2bac1d09 100644 (file)
--- a/fs/smb/client/cifs_debug.c
+++ b/fs/smb/client/cifs_debug.c
@@ -136,6 +136,11 @@ 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 e55f49e278a2ead5c8b5d449feecbea09d59710e..eae138040edf9bc548ff0cd69ad75ef801518520 100644 (file)
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1050,6 +1050,7 @@ 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 890ceddae07e25da236aea9ed4627198527c97ee..c1f71c6be7e353e788e0d1f704f4cec7e033d59d 100644 (file)
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -616,7 +616,7 @@ 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 1a137b33858a1fc905bd1ca8630151c45778431b..3ff82f0aa00e8dc49ead272237c2afad5cb6f0dd 100644 (file)
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -173,8 +173,12 @@ 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 829c7688a7b72df1fd21e7ea75f8041491a486b1..d13a2461371051c9b9e6152a5bb232287dbd94c7 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;
@@ -269,7 +284,7 @@ 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;
        }
@@ -319,6 +334,11 @@ 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 23c50ed7d4b590d9802ba15c9f9b2d263ac86753..84ea67301303c45c805fafc9bb2f5648655ec728 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);