From 88675b22d34e6e815ad4bde09c590ccb2d50c59d Mon Sep 17 00:00:00 2001 From: Shyam Prasad N Date: Thu, 1 Feb 2024 11:15:28 +0000 Subject: cifs: do not search for channel if server is terminating In order to scale down the channels, the following sequence of operations happen: 1. server struct is marked for terminate 2. the channel is deallocated in the ses->chans array 3. at a later point the cifsd thread actually terminates the server Between 2 and 3, there can be calls to find the channel for a server struct. When that happens, there can be an ugly warning that's logged. But this is expected. So this change does two things: 1. in cifs_ses_get_chan_index, if server->terminate is set, return 2. always make sure server->terminate is set with chan_lock held Signed-off-by: Shyam Prasad N Signed-off-by: Steve French --- fs/smb/client/sess.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/smb/client/sess.c') diff --git a/fs/smb/client/sess.c b/fs/smb/client/sess.c index cde81042bebd..3d2548c35c9d 100644 --- a/fs/smb/client/sess.c +++ b/fs/smb/client/sess.c @@ -75,6 +75,10 @@ cifs_ses_get_chan_index(struct cifs_ses *ses, { unsigned int i; + /* if the channel is waiting for termination */ + if (server->terminate) + return CIFS_INVAL_CHAN_INDEX; + for (i = 0; i < ses->chan_count; i++) { if (ses->chans[i].server == server) return i; -- cgit v1.2.3 From 6aac002bcfd554aff6d3ebb55e1660d078d70ab0 Mon Sep 17 00:00:00 2001 From: Shyam Prasad N Date: Thu, 1 Feb 2024 11:15:29 +0000 Subject: cifs: failure to add channel on iface should bump up weight After the interface selection policy change to do a weighted round robin, each iface maintains a weight_fulfilled. When the weight_fulfilled reaches the total weight for the iface, we know that the weights can be reset and ifaces can be allocated from scratch again. During channel allocation failures on a particular channel, weight_fulfilled is not incremented. If a few interfaces are inactive, we could end up in a situation where the active interfaces are all allocated for the total_weight, and inactive ones are all that remain. This can cause a situation where no more channels can be allocated further. This change fixes it by increasing weight_fulfilled, even when channel allocation failure happens. This could mean that if there are temporary failures in channel allocation, the iface weights may not strictly be adhered to. But that's still okay. Fixes: a6d8fb54a515 ("cifs: distribute channels across interfaces based on speed") Signed-off-by: Shyam Prasad N Signed-off-by: Steve French --- fs/smb/client/sess.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/smb/client/sess.c') diff --git a/fs/smb/client/sess.c b/fs/smb/client/sess.c index 3d2548c35c9d..ed4bd88dd528 100644 --- a/fs/smb/client/sess.c +++ b/fs/smb/client/sess.c @@ -273,6 +273,8 @@ int cifs_try_adding_channels(struct cifs_ses *ses) &iface->sockaddr, rc); kref_put(&iface->refcount, release_iface); + /* failure to add chan should increase weight */ + iface->weight_fulfilled++; continue; } -- cgit v1.2.3 From 45be0882c5f91e1b92e645001dd1a53b3bd58c97 Mon Sep 17 00:00:00 2001 From: Steve French Date: Mon, 5 Feb 2024 14:43:17 -0600 Subject: smb3: add missing null server pointer check Address static checker warning in cifs_ses_get_chan_index(): warn: variable dereferenced before check 'server' To be consistent, and reduce risk, we should add another check for null server pointer. Fixes: 88675b22d34e ("cifs: do not search for channel if server is terminating") Reported-by: Dan Carpenter Reviewed-by: Shyam Prasad N Signed-off-by: Steve French --- fs/smb/client/sess.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/smb/client/sess.c') diff --git a/fs/smb/client/sess.c b/fs/smb/client/sess.c index ed4bd88dd528..476d54fceb50 100644 --- a/fs/smb/client/sess.c +++ b/fs/smb/client/sess.c @@ -76,7 +76,7 @@ cifs_ses_get_chan_index(struct cifs_ses *ses, unsigned int i; /* if the channel is waiting for termination */ - if (server->terminate) + if (server && server->terminate) return CIFS_INVAL_CHAN_INDEX; for (i = 0; i < ses->chan_count; i++) { -- cgit v1.2.3 From a39c757bf0596b17482a507f31c3ef0af0d1d2b4 Mon Sep 17 00:00:00 2001 From: Shyam Prasad N Date: Tue, 6 Feb 2024 15:00:47 +0000 Subject: cifs: handle cases where multiple sessions share connection Based on our implementation of multichannel, it is entirely possible that a server struct may not be found in any channel of an SMB session. In such cases, we should be prepared to move on and search for the server struct in the next session. Signed-off-by: Shyam Prasad N Signed-off-by: Steve French --- fs/smb/client/sess.c | 1 - 1 file changed, 1 deletion(-) (limited to 'fs/smb/client/sess.c') diff --git a/fs/smb/client/sess.c b/fs/smb/client/sess.c index 476d54fceb50..8f37373fd333 100644 --- a/fs/smb/client/sess.c +++ b/fs/smb/client/sess.c @@ -88,7 +88,6 @@ cifs_ses_get_chan_index(struct cifs_ses *ses, if (server) cifs_dbg(VFS, "unable to get chan index for server: 0x%llx", server->conn_id); - WARN_ON(1); return CIFS_INVAL_CHAN_INDEX; } -- cgit v1.2.3