korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-01 08:04:22 +08:00
Code Issues Packages Projects Releases Wiki Activity

cifs: avoid races in parallel reconnects in smb1

Browse Source 
Prevent multiple threads of doing negotiate, session setup and tree
connect by holding @ses->session_mutex in cifs_reconnect_tcon() while
reconnecting session and tcon.

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara 2023-03-29 17:14:21 -03:00 committed by Steve French
parent 179a88a855
commit 6cc041e90c
1 changed files with 15 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
fs/cifs/cifssmb.c
View File

@ -71,7 +71,7 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
int rc; int rc;
struct cifs_ses *ses; struct cifs_ses *ses;
struct TCP_Server_Info *server; struct TCP_Server_Info *server;
struct nls_table *nls_codepage; struct nls_table *nls_codepage = NULL;
/* /*
* SMBs NegProt, SessSetup, uLogoff do not have tcon yet so check for * SMBs NegProt, SessSetup, uLogoff do not have tcon yet so check for
@ -99,6 +99,7 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
} }
spin_unlock(&tcon->tc_lock); spin_unlock(&tcon->tc_lock);
again:
rc = cifs_wait_for_server_reconnect(server, tcon->retry); rc = cifs_wait_for_server_reconnect(server, tcon->retry);
if (rc) if (rc)
return rc; return rc;
@ -110,8 +111,7 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
} }
spin_unlock(&ses->chan_lock); spin_unlock(&ses->chan_lock);
nls_codepage = load_nls_default(); mutex_lock(&ses->session_mutex);
/* /*
* Recheck after acquire mutex. If another thread is negotiating * Recheck after acquire mutex. If another thread is negotiating
* and the server never sends an answer the socket will be closed * and the server never sends an answer the socket will be closed
@ -120,29 +120,38 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
spin_lock(&server->srv_lock); spin_lock(&server->srv_lock);
if (server->tcpStatus == CifsNeedReconnect) { if (server->tcpStatus == CifsNeedReconnect) {
spin_unlock(&server->srv_lock); spin_unlock(&server->srv_lock);
mutex_lock(&ses->session_mutex);
if (tcon->retry)
goto again;
rc = -EHOSTDOWN; rc = -EHOSTDOWN;
goto out; goto out;
} }
spin_unlock(&server->srv_lock); spin_unlock(&server->srv_lock);
nls_codepage = load_nls_default();
/* /*
* need to prevent multiple threads trying to simultaneously * need to prevent multiple threads trying to simultaneously
* reconnect the same SMB session * reconnect the same SMB session
*/ */
spin_lock(&ses->ses_lock);
spin_lock(&ses->chan_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->chan_lock);
spin_unlock(&ses->ses_lock);
/* this means that we only need to tree connect */ /* this means that we only need to tree connect */
if (tcon->need_reconnect) if (tcon->need_reconnect)
goto skip_sess_setup; goto skip_sess_setup;
rc = -EHOSTDOWN; mutex_unlock(&ses->session_mutex);
goto out; goto out;
} }
spin_unlock(&ses->chan_lock); spin_unlock(&ses->chan_lock);
spin_unlock(&ses->ses_lock);
mutex_lock(&ses->session_mutex);
rc = cifs_negotiate_protocol(0, ses, server); rc = cifs_negotiate_protocol(0, ses, server);
if (!rc) if (!rc)
rc = cifs_setup_session(0, ses, server, nls_codepage); rc = cifs_setup_session(0, ses, server, nls_codepage);