diff options
| author | Shyam Prasad N <sprasad@microsoft.com> | 2024-01-29 13:58:13 +0000 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2024-01-31 16:52:03 -0600 |
| commit | ee36a3b345c433a846effcdcfba437c2298eeda5 (patch) | |
| tree | f99497ee1999bc0b09b525b22bc78eb9adf979e9 /fs | |
| parent | 41bccc98fb7931d63d03f326a746ac4d429c1dd3 (diff) | |
cifs: make sure that channel scaling is done only once
Following a successful cifs_tree_connect, we have the code
to scale up/down the number of channels in the session.
However, it is not protected by a lock today.
As a result, this code can be executed by several processes
that select the same channel. The core functions handle this
well, as they pick chan_lock. However, we've seen cases where
smb2_reconnect throws some warnings.
To fix that, this change introduces a flags bitmap inside the
cifs_ses structure. A new flag type is used to ensure that
only one process enters this section at any time.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/smb/client/cifsglob.h | 3 | ||||
| -rw-r--r-- | fs/smb/client/smb2pdu.c | 20 |
2 files changed, 20 insertions, 3 deletions
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h index 16befff4cbb4..9093c507042f 100644 --- a/fs/smb/client/cifsglob.h +++ b/fs/smb/client/cifsglob.h @@ -1032,6 +1032,8 @@ struct cifs_chan { __u8 signkey[SMB3_SIGN_KEY_SIZE]; }; +#define CIFS_SES_FLAG_SCALE_CHANNELS (0x1) + /* * Session structure. One of these for each uid session with a particular host */ @@ -1064,6 +1066,7 @@ struct cifs_ses { enum securityEnum sectype; /* what security flavor was specified? */ bool sign; /* is signing required? */ bool domainAuto:1; + unsigned int flags; __u16 session_flags; __u8 smb3signingkey[SMB3_SIGN_KEY_SIZE]; __u8 smb3encryptionkey[SMB3_ENC_DEC_KEY_SIZE]; diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c index 86f6f35b7f32..6db54c6ef571 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -399,6 +399,15 @@ skip_sess_setup: goto out; } + spin_lock(&ses->ses_lock); + if (ses->flags & CIFS_SES_FLAG_SCALE_CHANNELS) { + spin_unlock(&ses->ses_lock); + mutex_unlock(&ses->session_mutex); + goto skip_add_channels; + } + ses->flags |= CIFS_SES_FLAG_SCALE_CHANNELS; + spin_unlock(&ses->ses_lock); + if (!rc && (server->capabilities & SMB2_GLOBAL_CAP_MULTI_CHANNEL)) { mutex_unlock(&ses->session_mutex); @@ -428,17 +437,22 @@ skip_sess_setup: if (ses->chan_max > ses->chan_count && ses->iface_count && !SERVER_IS_CHAN(server)) { - if (ses->chan_count == 1) + if (ses->chan_count == 1) { cifs_server_dbg(VFS, "supports multichannel now\n"); + queue_delayed_work(cifsiod_wq, &tcon->query_interfaces, + (SMB_INTERFACE_POLL_INTERVAL * HZ)); + } cifs_try_adding_channels(ses); - queue_delayed_work(cifsiod_wq, &tcon->query_interfaces, - (SMB_INTERFACE_POLL_INTERVAL * HZ)); } } else { mutex_unlock(&ses->session_mutex); } + skip_add_channels: + spin_lock(&ses->ses_lock); + ses->flags &= ~CIFS_SES_FLAG_SCALE_CHANNELS; + spin_unlock(&ses->ses_lock); if (smb2_command != SMB2_INTERNAL_CMD) mod_delayed_work(cifsiod_wq, &server->reconnect, 0); |