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>
---
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
