diff options
author | Shyam Prasad N <sprasad@microsoft.com> | 2023-03-20 09:08:19 +0300 |
---|---|---|
committer | Steve French <stfrench@microsoft.com> | 2023-03-24 17:03:55 +0300 |
commit | bc962159e8e326af634a506508034a375bf2b858 (patch) | |
tree | 733ddaf358a6b9473122feca390378103bac5f58 /fs/cifs/smb2pdu.c | |
parent | fddc6ccc487e5de07b98df8d04118d5dcb5e0407 (diff) | |
download | linux-bc962159e8e326af634a506508034a375bf2b858.tar.xz |
cifs: avoid race conditions with parallel reconnects
When multiple processes/channels do reconnects in parallel
we used to return success immediately
negotiate/session-setup/tree-connect, causing race conditions
between processes that enter the function in parallel.
This caused several errors related to session not found to
show up during parallel reconnects.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs/smb2pdu.c')
-rw-r--r-- | fs/cifs/smb2pdu.c | 44 |
1 files changed, 26 insertions, 18 deletions
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index caeb92a69b5f..a9fb95b7ef82 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -203,6 +203,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, } spin_unlock(&server->srv_lock); +again: rc = cifs_wait_for_server_reconnect(server, tcon->retry); if (rc) return rc; @@ -221,6 +222,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, nls_codepage = load_nls_default(); + mutex_lock(&ses->session_mutex); /* * Recheck after acquire mutex. If another thread is negotiating * and the server never sends an answer the socket will be closed @@ -229,6 +231,11 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, spin_lock(&server->srv_lock); if (server->tcpStatus == CifsNeedReconnect) { spin_unlock(&server->srv_lock); + mutex_unlock(&ses->session_mutex); + + if (tcon->retry) + goto again; + rc = -EHOSTDOWN; goto out; } @@ -238,19 +245,22 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, * need to prevent multiple threads trying to simultaneously * reconnect the same SMB session */ + spin_lock(&ses->ses_lock); spin_lock(&ses->chan_lock); - if (!cifs_chan_needs_reconnect(ses, server)) { + if (!cifs_chan_needs_reconnect(ses, server) && + ses->ses_status == SES_GOOD) { spin_unlock(&ses->chan_lock); - + spin_unlock(&ses->ses_lock); /* this means that we only need to tree connect */ if (tcon->need_reconnect) goto skip_sess_setup; + mutex_unlock(&ses->session_mutex); goto out; } spin_unlock(&ses->chan_lock); + spin_unlock(&ses->ses_lock); - mutex_lock(&ses->session_mutex); rc = cifs_negotiate_protocol(0, ses, server); if (!rc) { rc = cifs_setup_session(0, ses, server, nls_codepage); @@ -266,10 +276,8 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, mutex_unlock(&ses->session_mutex); goto out; } - mutex_unlock(&ses->session_mutex); skip_sess_setup: - mutex_lock(&ses->session_mutex); if (!tcon->need_reconnect) { mutex_unlock(&ses->session_mutex); goto out; @@ -284,7 +292,7 @@ skip_sess_setup: cifs_dbg(FYI, "reconnect tcon rc = %d\n", rc); if (rc) { /* If sess reconnected but tcon didn't, something strange ... */ - pr_warn_once("reconnect tcon failed rc = %d\n", rc); + cifs_dbg(VFS, "reconnect tcon failed rc = %d\n", rc); goto out; } @@ -1256,9 +1264,9 @@ SMB2_sess_alloc_buffer(struct SMB2_sess_data *sess_data) if (rc) return rc; - spin_lock(&ses->chan_lock); - is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses); - spin_unlock(&ses->chan_lock); + spin_lock(&ses->ses_lock); + is_binding = (ses->ses_status == SES_GOOD); + spin_unlock(&ses->ses_lock); if (is_binding) { req->hdr.SessionId = cpu_to_le64(ses->Suid); @@ -1416,9 +1424,9 @@ SMB2_auth_kerberos(struct SMB2_sess_data *sess_data) goto out_put_spnego_key; } - spin_lock(&ses->chan_lock); - is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses); - spin_unlock(&ses->chan_lock); + spin_lock(&ses->ses_lock); + is_binding = (ses->ses_status == SES_GOOD); + spin_unlock(&ses->ses_lock); /* keep session key if binding */ if (!is_binding) { @@ -1542,9 +1550,9 @@ SMB2_sess_auth_rawntlmssp_negotiate(struct SMB2_sess_data *sess_data) cifs_dbg(FYI, "rawntlmssp session setup challenge phase\n"); - spin_lock(&ses->chan_lock); - is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses); - spin_unlock(&ses->chan_lock); + spin_lock(&ses->ses_lock); + is_binding = (ses->ses_status == SES_GOOD); + spin_unlock(&ses->ses_lock); /* keep existing ses id and flags if binding */ if (!is_binding) { @@ -1610,9 +1618,9 @@ SMB2_sess_auth_rawntlmssp_authenticate(struct SMB2_sess_data *sess_data) rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base; - spin_lock(&ses->chan_lock); - is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses); - spin_unlock(&ses->chan_lock); + spin_lock(&ses->ses_lock); + is_binding = (ses->ses_status == SES_GOOD); + spin_unlock(&ses->ses_lock); /* keep existing ses id and flags if binding */ if (!is_binding) { |