diff options
author | Paulo Alcantara <pc@cjr.nz> | 2023-01-31 02:33:29 +0300 |
---|---|---|
committer | Steve French <stfrench@microsoft.com> | 2023-02-20 20:48:48 +0300 |
commit | 3c0070f54b3128de498c2dd9934a21f0dd867111 (patch) | |
tree | 115759dc2568311988bf02bfa72e52388ca3f163 /fs/cifs/smb2pdu.c | |
parent | 77e3f338df79b4584ec4a518e43db38455a6dfb3 (diff) | |
download | linux-3c0070f54b3128de498c2dd9934a21f0dd867111.tar.xz |
cifs: prevent data race in smb2_reconnect()
Make sure to get an up-to-date TCP_Server_Info::nr_targets value prior
to waiting the server to be reconnected in smb2_reconnect(). It is
set in cifs_tcp_ses_needs_reconnect() and protected by
TCP_Server_Info::srv_lock.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs/smb2pdu.c')
-rw-r--r-- | fs/cifs/smb2pdu.c | 119 |
1 files changed, 64 insertions, 55 deletions
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 2c9ffa921e6f..2d5c3df2277d 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -139,6 +139,66 @@ out: return; } +static int wait_for_server_reconnect(struct TCP_Server_Info *server, + __le16 smb2_command, bool retry) +{ + int timeout = 10; + int rc; + + spin_lock(&server->srv_lock); + if (server->tcpStatus != CifsNeedReconnect) { + spin_unlock(&server->srv_lock); + return 0; + } + timeout *= server->nr_targets; + spin_unlock(&server->srv_lock); + + /* + * Return to caller for TREE_DISCONNECT and LOGOFF and CLOSE + * here since they are implicitly done when session drops. + */ + switch (smb2_command) { + /* + * BB Should we keep oplock break and add flush to exceptions? + */ + case SMB2_TREE_DISCONNECT: + case SMB2_CANCEL: + case SMB2_CLOSE: + case SMB2_OPLOCK_BREAK: + return -EAGAIN; + } + + /* + * Give demultiplex thread up to 10 seconds to each target available for + * reconnect -- should be greater than cifs socket timeout which is 7 + * seconds. + * + * On "soft" mounts we wait once. Hard mounts keep retrying until + * process is killed or server comes back on-line. + */ + do { + rc = wait_event_interruptible_timeout(server->response_q, + (server->tcpStatus != CifsNeedReconnect), + timeout * HZ); + if (rc < 0) { + cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n", + __func__); + return -ERESTARTSYS; + } + + /* are we still trying to reconnect? */ + spin_lock(&server->srv_lock); + if (server->tcpStatus != CifsNeedReconnect) { + spin_unlock(&server->srv_lock); + return 0; + } + spin_unlock(&server->srv_lock); + } while (retry); + + cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__); + return -EHOSTDOWN; +} + static int smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, struct TCP_Server_Info *server) @@ -146,7 +206,6 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, int rc = 0; struct nls_table *nls_codepage; struct cifs_ses *ses; - int retries; /* * SMB2s NegProt, SessSetup, Logoff do not have tcon yet so @@ -184,61 +243,11 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon, (!tcon->ses->server) || !server) return -EIO; - ses = tcon->ses; - retries = server->nr_targets; - - /* - * Give demultiplex thread up to 10 seconds to each target available for - * reconnect -- should be greater than cifs socket timeout which is 7 - * seconds. - */ - while (server->tcpStatus == CifsNeedReconnect) { - /* - * Return to caller for TREE_DISCONNECT and LOGOFF and CLOSE - * here since they are implicitly done when session drops. - */ - switch (smb2_command) { - /* - * BB Should we keep oplock break and add flush to exceptions? - */ - case SMB2_TREE_DISCONNECT: - case SMB2_CANCEL: - case SMB2_CLOSE: - case SMB2_OPLOCK_BREAK: - return -EAGAIN; - } - - rc = wait_event_interruptible_timeout(server->response_q, - (server->tcpStatus != CifsNeedReconnect), - 10 * HZ); - if (rc < 0) { - cifs_dbg(FYI, "%s: aborting reconnect due to a received signal by the process\n", - __func__); - return -ERESTARTSYS; - } - - /* are we still trying to reconnect? */ - spin_lock(&server->srv_lock); - if (server->tcpStatus != CifsNeedReconnect) { - spin_unlock(&server->srv_lock); - break; - } - spin_unlock(&server->srv_lock); - - if (retries && --retries) - continue; + rc = wait_for_server_reconnect(server, smb2_command, tcon->retry); + if (rc) + return rc; - /* - * on "soft" mounts we wait once. Hard mounts keep - * retrying until process is killed or server comes - * back on-line - */ - if (!tcon->retry) { - cifs_dbg(FYI, "gave up waiting on reconnect in smb_init\n"); - return -EHOSTDOWN; - } - retries = server->nr_targets; - } + ses = tcon->ses; spin_lock(&ses->chan_lock); if (!cifs_chan_needs_reconnect(ses, server) && !tcon->need_reconnect) { |