diff options
| author |   Pavel Shilovsky <pshilov@microsoft.com> | 2019-01-15 16:07:52 -0800 |
|---|---|---|
| committer |   Steve French <stfrench@microsoft.com> | 2019-03-05 18:10:01 -0600 |
| commit | 97ea499883cc0566b1fafdc12ca49d0926aab332 (patch) | |
| tree | 14c725575336fb73934c03d96743c4f13924d79b /fs/cifs/transport.c | |
| parent | CIFS: Check for reconnects before sending async requests (diff) | |
| download | linux-dev-97ea499883cc0566b1fafdc12ca49d0926aab332.tar.xz linux-dev-97ea499883cc0566b1fafdc12ca49d0926aab332.zip | |
CIFS: Check for reconnects before sending compound requests
The reconnect might have happended after we obtained credits
and before we acquired srv_mutex. Check for that under the mutex
and retry a sync operation if the reconnect is detected.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs/transport.c')
| -rw-r--r-- | fs/cifs/transport.c | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index 5a3e499caec8..2045f886546c 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -843,6 +843,7 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, { .value = 0, .instance = 0 } }; unsigned int instance; + unsigned int first_instance = 0; char *buf; timeout = flags & CIFS_TIMEOUT_MASK; @@ -870,6 +871,25 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, for (i = 0; i < num_rqst; i++) { rc = wait_for_free_request(ses->server, timeout, optype, &instance); + + if (rc == 0) { + credits[i].value = 1; + credits[i].instance = instance; + /* + * All parts of the compound chain must get credits from + * the same session, otherwise we may end up using more + * credits than the server granted. If there were + * reconnects in between, return -EAGAIN and let callers + * handle it. + */ + if (i == 0) + first_instance = instance; + else if (first_instance != instance) { + i++; + rc = -EAGAIN; + } + } + if (rc) { /* * We haven't sent an SMB packet to the server yet but @@ -884,8 +904,6 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, add_credits(ses->server, &credits[j], optype); return rc; } - credits[i].value = 1; - credits[i].instance = instance; } /* @@ -896,6 +914,22 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, mutex_lock(&ses->server->srv_mutex); + /* + * All the parts of the compound chain belong obtained credits from the + * same session (see the appropriate checks above). In the same time + * there might be reconnects after those checks but before we acquired + * the srv_mutex. We can not 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 (first_instance != ses->server->reconnect_instance) { + mutex_unlock(&ses->server->srv_mutex); + for (j = 0; j < num_rqst; j++) + add_credits(ses->server, &credits[j], optype); + return -EAGAIN; + } + for (i = 0; i < num_rqst; i++) { midQ[i] = ses->server->ops->setup_request(ses, &rqst[i]); if (IS_ERR(midQ[i])) { |