| From d69cb728e70c40268762182a62f5d5d6fa51c5b2 Mon Sep 17 00:00:00 2001 |
| From: Ronnie Sahlberg <lsahlber@redhat.com> |
| Date: Wed, 1 May 2019 12:03:41 +1000 |
| Subject: cifs: fix credits leak for SMB1 oplock breaks |
| |
| From: Ronnie Sahlberg <lsahlber@redhat.com> |
| |
| commit d69cb728e70c40268762182a62f5d5d6fa51c5b2 upstream. |
| |
| For SMB1 oplock breaks we would grab one credit while sending the PDU |
| but we would never relese the credit back since we will never receive a |
| response to this from the server. Eventuallt this would lead to a hang |
| once all credits are leaked. |
| |
| Fix this by defining a new flag CIFS_NO_SRV_RSP which indicates that there |
| is no server response to this command and thus we need to add any credits back |
| immediately after sending the PDU. |
| |
| CC: Stable <stable@vger.kernel.org> #v5.0+ |
| Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> |
| Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> |
| Signed-off-by: Steve French <stfrench@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/cifs/cifsglob.h | 1 + |
| fs/cifs/cifssmb.c | 2 +- |
| fs/cifs/transport.c | 10 +++++----- |
| 3 files changed, 7 insertions(+), 6 deletions(-) |
| |
| --- a/fs/cifs/cifsglob.h |
| +++ b/fs/cifs/cifsglob.h |
| @@ -1657,6 +1657,7 @@ static inline bool is_retryable_error(in |
| |
| #define CIFS_HAS_CREDITS 0x0400 /* already has credits */ |
| #define CIFS_TRANSFORM_REQ 0x0800 /* transform request before sending */ |
| +#define CIFS_NO_SRV_RSP 0x1000 /* there is no server response */ |
| |
| /* Security Flags: indicate type of session setup needed */ |
| #define CIFSSEC_MAY_SIGN 0x00001 |
| --- a/fs/cifs/cifssmb.c |
| +++ b/fs/cifs/cifssmb.c |
| @@ -2533,7 +2533,7 @@ CIFSSMBLock(const unsigned int xid, stru |
| |
| if (lockType == LOCKING_ANDX_OPLOCK_RELEASE) { |
| /* no response expected */ |
| - flags = CIFS_ASYNC_OP | CIFS_OBREAK_OP; |
| + flags = CIFS_NO_SRV_RSP | CIFS_ASYNC_OP | CIFS_OBREAK_OP; |
| pSMB->Timeout = 0; |
| } else if (waitFlag) { |
| flags = CIFS_BLOCKING_OP; /* blocking operation, no timeout */ |
| --- a/fs/cifs/transport.c |
| +++ b/fs/cifs/transport.c |
| @@ -906,8 +906,11 @@ compound_send_recv(const unsigned int xi |
| |
| mutex_unlock(&ses->server->srv_mutex); |
| |
| - if (rc < 0) { |
| - /* Sending failed for some reason - return credits back */ |
| + /* |
| + * If sending failed for some reason or it is an oplock break that we |
| + * will not receive a response to - return credits back |
| + */ |
| + if (rc < 0 || (flags & CIFS_NO_SRV_RSP)) { |
| for (i = 0; i < num_rqst; i++) |
| add_credits(ses->server, credits[i], optype); |
| goto out; |
| @@ -928,9 +931,6 @@ compound_send_recv(const unsigned int xi |
| smb311_update_preauth_hash(ses, rqst[0].rq_iov, |
| rqst[0].rq_nvec); |
| |
| - if (timeout == CIFS_ASYNC_OP) |
| - goto out; |
| - |
| for (i = 0; i < num_rqst; i++) { |
| rc = wait_for_response(ses->server, midQ[i]); |
| if (rc != 0) |