diff options
| author |   Shyam Prasad N <sprasad@microsoft.com> | 2021-10-25 05:44:10 +0000 |
|---|---|---|
| committer |   Steve French <stfrench@microsoft.com> | 2022-01-07 20:09:23 -0600 |
| commit | bda487ac4bebf871255cc6f23e16f702cea0ca7c (patch) | |
| tree | c9002fe22f2e9294726411f82e012835ffef95ac /fs/cifs/connect.c | |
| parent | cifs: maintain a state machine for tcp/smb/tcon sessions (diff) | |
| download | linux-dev-bda487ac4bebf871255cc6f23e16f702cea0ca7c.tar.xz linux-dev-bda487ac4bebf871255cc6f23e16f702cea0ca7c.zip | |
cifs: avoid race during socket reconnect between send and recv
When a TCP connection gets reestablished by the sender in cifs_reconnect,
There is a chance for race condition with demultiplex thread waiting in
cifs_readv_from_socket on the old socket. It will now return -ECONNRESET.
This condition is handled by comparing socket pointer before and after
sock_recvmsg. If the socket pointer has changed, we should not call
cifs_reconnect again, but instead retry with new socket.
Also fixed another bug in my prev mchan commits.
We should always reestablish session (even if binding) on a channel
that needs reconnection.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs/connect.c')
| -rw-r--r-- | fs/cifs/connect.c | 14 |
1 files changed, 3 insertions, 11 deletions
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index a408187c7002..1dafaf7c4e5e 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -172,12 +172,11 @@ static void cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server, bool mark_smb_session) { - unsigned int num_sessions = 0; + struct TCP_Server_Info *pserver; struct cifs_ses *ses; struct cifs_tcon *tcon; struct mid_q_entry *mid, *nmid; struct list_head retry_list; - struct TCP_Server_Info *pserver; server->maxBuf = 0; server->max_read = 0; @@ -199,17 +198,13 @@ cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server, if (!mark_smb_session && cifs_chan_needs_reconnect(ses, server)) goto next_session; - if (mark_smb_session) - CIFS_SET_ALL_CHANS_NEED_RECONNECT(ses); - else - cifs_chan_set_need_reconnect(ses, server); + cifs_chan_set_need_reconnect(ses, server); /* If all channels need reconnect, then tcon needs reconnect */ if (!mark_smb_session && !CIFS_ALL_CHANS_NEED_RECONNECT(ses)) goto next_session; ses->status = CifsNeedReconnect; - num_sessions++; list_for_each_entry(tcon, &ses->tcon_list, tcon_list) { tcon->need_reconnect = true; @@ -223,16 +218,13 @@ next_session: } spin_unlock(&cifs_tcp_ses_lock); - if (num_sessions == 0) - return; /* * before reconnecting the tcp session, mark the smb session (uid) * and the tid bad so they are not used until reconnected */ - cifs_dbg(FYI, "%s: marking sessions and tcons for reconnect\n", + cifs_dbg(FYI, "%s: marking sessions and tcons for reconnect and tearing down socket\n", __func__); /* do not want to be sending data on a socket we are freeing */ - cifs_dbg(FYI, "%s: tearing down socket\n", __func__); mutex_lock(&server->srv_mutex); if (server->ssocket) { cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n", server->ssocket->state, |