cifs: do not send close in compound create+close requests

In case of interrupted syscalls, prevent sending CLOSE commands for
compound CREATE+CLOSE requests by introducing an
CIFS_CP_CREATE_CLOSE_OP flag to indicate lower layers that it should
not send a CLOSE command to the MIDs corresponding the compound
CREATE+CLOSE request.

A simple reproducer:

    #!/bin/bash

    mount //server/share /mnt -o username=foo,password=***
    tc qdisc add dev eth0 root netem delay 450ms
    stat -f /mnt &>/dev/null & pid=$!
    sleep 0.01
    kill $pid
    tc qdisc del dev eth0 root
    umount /mnt

Before patch:

    ...
    6 0.256893470 192.168.122.2 → 192.168.122.15 SMB2 402 Create Request File: ;GetInfo Request FS_INFO/FileFsFullSizeInformation;Close Request
    7 0.257144491 192.168.122.15 → 192.168.122.2 SMB2 498 Create Response File: ;GetInfo Response;Close Response
    9 0.260798209 192.168.122.2 → 192.168.122.15 SMB2 146 Close Request File:
   10 0.260841089 192.168.122.15 → 192.168.122.2 SMB2 130 Close Response, Error: STATUS_FILE_CLOSED
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsglob.h

@@ -257,7 +257,7 @@ struct smb_version_operations {
 	/* verify the message */
 	int (*check_message)(char *, unsigned int, struct TCP_Server_Info *);
 	bool (*is_oplock_break)(char *, struct TCP_Server_Info *);
-	int (*handle_cancelled_mid)(char *, struct TCP_Server_Info *);
+	int (*handle_cancelled_mid)(struct mid_q_entry *, struct TCP_Server_Info *);
 	void (*downgrade_oplock)(struct TCP_Server_Info *server,
 				 struct cifsInodeInfo *cinode, __u32 oplock,
 				 unsigned int epoch, bool *purge_cache);
@@ -1708,9 +1708,10 @@ static inline bool is_retryable_error(int error)
 #define   CIFS_ECHO_OP            0x080  /* echo request */
 #define   CIFS_OBREAK_OP          0x0100 /* oplock break request */
 #define   CIFS_NEG_OP             0x0200 /* negotiate request */
+#define   CIFS_CP_CREATE_CLOSE_OP 0x0400 /* compound create+close request */
 /* Lower bitmask values are reserved by others below. */
 #define   CIFS_SESS_OP            0x2000 /* session setup request */
-#define   CIFS_OP_MASK     0x2380    /* mask request type */
+#define   CIFS_OP_MASK            0x2780 /* mask request type */
 
 #define   CIFS_HAS_CREDITS        0x0400 /* already has credits */
 #define   CIFS_TRANSFORM_REQ      0x0800 /* transform request before sending */

fs/cifs/smb2inode.c

@@ -358,6 +358,7 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 	if (cfile)
 		goto after_close;
 	/* Close */
+	flags |= CIFS_CP_CREATE_CLOSE_OP;
 	rqst[num_rqst].rq_iov = &vars->close_iov[0];
 	rqst[num_rqst].rq_nvec = 1;
 	rc = SMB2_close_init(tcon, server,

fs/cifs/smb2misc.c

@@ -844,14 +844,14 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid,
 }
 
 int
-smb2_handle_cancelled_mid(char *buffer, struct TCP_Server_Info *server)
+smb2_handle_cancelled_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 {
-	struct smb2_sync_hdr *sync_hdr = (struct smb2_sync_hdr *)buffer;
-	struct smb2_create_rsp *rsp = (struct smb2_create_rsp *)buffer;
+	struct smb2_sync_hdr *sync_hdr = mid->resp_buf;
+	struct smb2_create_rsp *rsp = mid->resp_buf;
 	struct cifs_tcon *tcon;
 	int rc;
 
-	if (sync_hdr->Command != SMB2_CREATE ||
+	if ((mid->optype & CIFS_CP_CREATE_CLOSE_OP) || sync_hdr->Command != SMB2_CREATE ||
 	    sync_hdr->Status != STATUS_SUCCESS)
 		return 0;
 

fs/cifs/smb2ops.c

@@ -1195,7 +1195,7 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	__le16 *utf16_path = NULL;
 	int ea_name_len = strlen(ea_name);
-	int flags = 0;
+	int flags = CIFS_CP_CREATE_CLOSE_OP;
 	int len;
 	struct smb_rqst rqst[3];
 	int resp_buftype[3];
@@ -1573,7 +1573,7 @@ smb2_ioctl_query_info(const unsigned int xid,
 	struct smb_query_info qi;
 	struct smb_query_info __user *pqi;
 	int rc = 0;
-	int flags = 0;
+	int flags = CIFS_CP_CREATE_CLOSE_OP;
 	struct smb2_query_info_rsp *qi_rsp = NULL;
 	struct smb2_ioctl_rsp *io_rsp = NULL;
 	void *buffer = NULL;
@@ -2577,7 +2577,7 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 {
 	struct cifs_ses *ses = tcon->ses;
 	struct TCP_Server_Info *server = cifs_pick_channel(ses);
-	int flags = 0;
+	int flags = CIFS_CP_CREATE_CLOSE_OP;
 	struct smb_rqst rqst[3];
 	int resp_buftype[3];
 	struct kvec rsp_iov[3];
@@ -2975,7 +2975,7 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	unsigned int sub_offset;
 	unsigned int print_len;
 	unsigned int print_offset;
-	int flags = 0;
+	int flags = CIFS_CP_CREATE_CLOSE_OP;
 	struct smb_rqst rqst[3];
 	int resp_buftype[3];
 	struct kvec rsp_iov[3];
@@ -3157,7 +3157,7 @@ smb2_query_reparse_tag(const unsigned int xid, struct cifs_tcon *tcon,
 	struct cifs_open_parms oparms;
 	struct cifs_fid fid;
 	struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);
-	int flags = 0;
+	int flags = CIFS_CP_CREATE_CLOSE_OP;
 	struct smb_rqst rqst[3];
 	int resp_buftype[3];
 	struct kvec rsp_iov[3];

fs/cifs/smb2proto.h

@@ -246,8 +246,7 @@ extern int SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
 extern int smb2_handle_cancelled_close(struct cifs_tcon *tcon,
 				       __u64 persistent_fid,
 				       __u64 volatile_fid);
-extern int smb2_handle_cancelled_mid(char *buffer,
-					struct TCP_Server_Info *server);
+extern int smb2_handle_cancelled_mid(struct mid_q_entry *mid, struct TCP_Server_Info *server);
 void smb2_cancelled_close_fid(struct work_struct *work);
 extern int SMB2_QFS_info(const unsigned int xid, struct cifs_tcon *tcon,
 			 u64 persistent_file_id, u64 volatile_file_id,

fs/cifs/transport.c

@@ -101,7 +101,7 @@ static void _cifs_mid_q_entry_release(struct kref *refcount)
 	if (midEntry->resp_buf && (midEntry->mid_flags & MID_WAIT_CANCELLED) &&
 	    midEntry->mid_state == MID_RESPONSE_RECEIVED &&
 	    server->ops->handle_cancelled_mid)
-		server->ops->handle_cancelled_mid(midEntry->resp_buf, server);
+		server->ops->handle_cancelled_mid(midEntry, server);
 
 	midEntry->mid_state = MID_FREE;
 	atomic_dec(&midCount);