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Commit 3349c3a7 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Check for reconnects before sending async requests 



The reconnect might have happended after we obtained credits
and before we acquired srv_mutex. Check for that under the mutex
and retry an async operation if the reconnect is detected.

Signed-off-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 34f4deb7

fs/cifs/cifsproto.h

+2 −1
Original line number Diff line number Diff line
@@ -93,7 +93,8 @@ extern int cifs_discard_remaining_data(struct TCP_Server_Info *server); 
extern int cifs_call_async(struct TCP_Server_Info *server,

			struct smb_rqst *rqst,

			mid_receive_t *receive, mid_callback_t *callback,

			mid_handle_t *handle, void *cbdata, const int flags);

			mid_handle_t *handle, void *cbdata, const int flags,

			const struct cifs_credits *exist_credits);

extern int cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,

			  struct smb_rqst *rqst, int *resp_buf_type,

			  const int flags, struct kvec *resp_iov);

fs/cifs/cifssmb.c

+3 −3
Original line number Diff line number Diff line
@@ -860,7 +860,7 @@ CIFSSMBEcho(struct TCP_Server_Info *server) 
	iov[1].iov_base = (char *)smb + 4;



	rc = cifs_call_async(server, &rqst, NULL, cifs_echo_callback, NULL,

			     server, CIFS_ASYNC_OP | CIFS_ECHO_OP);

			     server, CIFS_ASYNC_OP | CIFS_ECHO_OP, NULL);

	if (rc)

		cifs_dbg(FYI, "Echo request failed: %d\n", rc);
@@ -1812,7 +1812,7 @@ cifs_async_readv(struct cifs_readdata *rdata) 


	kref_get(&rdata->refcount);

	rc = cifs_call_async(tcon->ses->server, &rqst, cifs_readv_receive,

			     cifs_readv_callback, NULL, rdata, 0);

			     cifs_readv_callback, NULL, rdata, 0, NULL);



	if (rc == 0)

		cifs_stats_inc(&tcon->stats.cifs_stats.num_reads);
@@ -2352,7 +2352,7 @@ cifs_async_writev(struct cifs_writedata *wdata, 


	kref_get(&wdata->refcount);

	rc = cifs_call_async(tcon->ses->server, &rqst, NULL,

				cifs_writev_callback, NULL, wdata, 0);

			     cifs_writev_callback, NULL, wdata, 0, NULL);



	if (rc == 0)

		cifs_stats_inc(&tcon->stats.cifs_stats.num_writes);

fs/cifs/smb2pdu.c

+4 −3
Original line number Diff line number Diff line
@@ -3034,7 +3034,7 @@ SMB2_echo(struct TCP_Server_Info *server) 
	iov[0].iov_base = (char *)req;



	rc = cifs_call_async(server, &rqst, NULL, smb2_echo_callback, NULL,

			     server, CIFS_ECHO_OP);

			     server, CIFS_ECHO_OP, NULL);

	if (rc)

		cifs_dbg(FYI, "Echo request failed: %d\n", rc);
@@ -3343,7 +3343,8 @@ smb2_async_readv(struct cifs_readdata *rdata) 
	kref_get(&rdata->refcount);

	rc = cifs_call_async(io_parms.tcon->ses->server, &rqst,

			     cifs_readv_receive, smb2_readv_callback,

			     smb3_handle_read_data, rdata, flags);

			     smb3_handle_read_data, rdata, flags,

			     &rdata->credits);

	if (rc) {

		kref_put(&rdata->refcount, cifs_readdata_release);

		cifs_stats_fail_inc(io_parms.tcon, SMB2_READ_HE);
@@ -3645,7 +3646,7 @@ smb2_async_writev(struct cifs_writedata *wdata, 


	kref_get(&wdata->refcount);

	rc = cifs_call_async(server, &rqst, NULL, smb2_writev_callback, NULL,

			     wdata, flags);

			     wdata, flags, &wdata->credits);



	if (rc) {

		trace_smb3_write_err(0 /* no xid */, req->PersistentFileId,

fs/cifs/transport.c

+16 −2
Original line number Diff line number Diff line
@@ -607,7 +607,8 @@ cifs_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst) 
int

cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,

		mid_receive_t *receive, mid_callback_t *callback,

		mid_handle_t *handle, void *cbdata, const int flags)

		mid_handle_t *handle, void *cbdata, const int flags,

		const struct cifs_credits *exist_credits)

{

	int rc, timeout, optype;

	struct mid_q_entry *mid;
@@ -623,9 +624,22 @@ cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst, 
			return rc;

		credits.value = 1;

		credits.instance = instance;

	}

	} else

		instance = exist_credits->instance;



	mutex_lock(&server->srv_mutex);



	/*

	 * We can't use credits obtained from the previous session to send this

	 * request. Check if there were reconnects after we obtained credits and

	 * return -EAGAIN in such cases to let callers handle it.

	 */

	if (instance != server->reconnect_instance) {

		mutex_unlock(&server->srv_mutex);

		add_credits_and_wake_if(server, &credits, optype);

		return -EAGAIN;

	}



	mid = server->ops->setup_async_request(server, rqst);

	if (IS_ERR(mid)) {

		mutex_unlock(&server->srv_mutex);