| Message ID | 20230130233329.7074-1-pc@cjr.nz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | cifs: prevent data race in smb2_reconnect() | expand |
tentatively merged into cifs-2.6.git for-next pending review/testing On Mon, Jan 30, 2023 at 5:33 PM Paulo Alcantara <pc@cjr.nz> wrote: > > 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> > --- > fs/cifs/smb2pdu.c | 119 +++++++++++++++++++++++++--------------------- > 1 file 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 @@ smb2_hdr_assemble(struct smb2_hdr *shdr, __le16 smb2_cmd, > 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; > > + rc = wait_for_server_reconnect(server, smb2_command, tcon->retry); > + if (rc) > + return rc; > + > 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; > - > - /* > - * 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; > - } > > spin_lock(&ses->chan_lock); > if (!cifs_chan_needs_reconnect(ses, server) && !tcon->need_reconnect) { > -- > 2.39.1 >
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 @@ smb2_hdr_assemble(struct smb2_hdr *shdr, __le16 smb2_cmd, 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; + rc = wait_for_server_reconnect(server, smb2_command, tcon->retry); + if (rc) + return rc; + 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; - - /* - * 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; - } spin_lock(&ses->chan_lock); if (!cifs_chan_needs_reconnect(ses, server) && !tcon->need_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> --- fs/cifs/smb2pdu.c | 119 +++++++++++++++++++++++++--------------------- 1 file changed, 64 insertions(+), 55 deletions(-)