| Message ID | 1549051452-5968-12-git-send-email-pshilov@microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Improve credits and error handling on reconnects | expand |
пт, 1 февр. 2019 г. в 12:04, Pavel Shilovsky <piastryyy@gmail.com>: > > 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@microsoft.com> > Signed-off-by: Steve French <stfrench@microsoft.com> > --- > 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
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