пт, 1 февр. 2019 г. в 12:04, Pavel Shilovsky <piastryyy@xxxxxxxxx>:
>
> We don't want to break a session if we receive a signal during
> sending a packet through the network. Fix it by masking signals
> during execution of sock_sendmsg() and then checking for pending
> signals.
>
> Signed-off-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
> ---
> fs/cifs/transport.c | 33 ++++++++++++++++++++++++++++++---
> 1 file changed, 30 insertions(+), 3 deletions(-)
>
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index 53532bd..eff9e3c 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -33,6 +33,7 @@
> #include <linux/uaccess.h>
> #include <asm/processor.h>
> #include <linux/mempool.h>
> +#include <linux/signal.h>
> #include "cifspdu.h"
> #include "cifsglob.h"
> #include "cifsproto.h"
> @@ -176,6 +177,7 @@ smb_send_kvec(struct TCP_Server_Info *server, struct msghdr *smb_msg,
> int rc = 0;
> int retries = 0;
> struct socket *ssocket = server->ssocket;
> + sigset_t mask, oldmask;
>
> *sent = 0;
>
> @@ -189,6 +191,28 @@ smb_send_kvec(struct TCP_Server_Info *server, struct msghdr *smb_msg,
> smb_msg->msg_flags = MSG_NOSIGNAL;
>
> while (msg_data_left(smb_msg)) {
> + if (signal_pending(current)) {
> + /* Should we stop sending if we receive SIG_KILL? */
> + if (__fatal_signal_pending(current))
> + cifs_dbg(FYI, "SIG_KILL signal is pending\n");
> +
> + /* It is safe to return if we haven't sent anything */
> + if (*sent == 0) {
> + cifs_dbg(FYI, "signal is pending before sending any data\n");
> + return -EINTR;
> + }
> + }
> +
> + /*
> + * We should not allow signals to interrupt the network send
> + * because any partial send will cause session reconnects thus
> + * increasing latency of system calls and overload a server
> + * with unnecessary requests.
> + */
> +
> + sigfillset(&mask);
> + sigprocmask(SIG_BLOCK, &mask, &oldmask);
> +
> /*
> * If blocking send, we try 3 times, since each can block
> * for 5 seconds. For nonblocking we have to try more
> @@ -208,20 +232,23 @@ smb_send_kvec(struct TCP_Server_Info *server, struct msghdr *smb_msg,
> * reconnect which may clear the network problem.
> */
> rc = sock_sendmsg(ssocket, smb_msg);
> +
> + sigprocmask(SIG_SETMASK, &oldmask, NULL);
> +
> if (rc == -EAGAIN) {
> retries++;
> if (retries >= 14 ||
> (!server->noblocksnd && (retries > 2))) {
> cifs_dbg(VFS, "sends on sock %p stuck for 15 seconds\n",
> ssocket);
> - return -EAGAIN;
> + return signal_pending(current) ? -EINTR : rc;
> }
> msleep(1 << retries);
> continue;
> }
>
> if (rc < 0)
> - return rc;
> + return signal_pending(current) ? -EINTR : rc;
>
> if (rc == 0) {
> /* should never happen, letting socket clear before
> @@ -235,7 +262,7 @@ smb_send_kvec(struct TCP_Server_Info *server, struct msghdr *smb_msg,
> *sent += rc;
> retries = 0; /* in case we get ENOSPC on the next send */
> }
> - return 0;
> + return signal_pending(current) ? -EINTR : 0;
> }
>
> unsigned long
> --
> 2.7.4
>
Please ignore this one. I posted the new version of it:
CIFS: Mask off signals when sending SMB packets
--
Best regards,
Pavel Shilovsky
