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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: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Pavel Shilovsky 2019-01-15 15:52:29 -08:00 committed by Steve French
parent 34f4deb7c5
commit 3349c3a79f
4 changed files with 25 additions and 9 deletions
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3
fs/cifs/cifsproto.h
View File

@ -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);

6
fs/cifs/cifssmb.c
View File

@ -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);

7
fs/cifs/smb2pdu.c
View File

@ -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,

18
fs/cifs/transport.c
View File

@ -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);