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)