A storage might sent an R2T response for a WRITE command while
we still sending out the WRITE command PDU. This is especially
the case when the command PDU carries immediata data.
Without this patch the R2T response will get lost as
the cmdpdu for the R2T cannot be found in iscsi_process_pdu()
leading to a deadlock.
Signed-off-by: Peter Lieven <pl@kamp.de>
This patch fixes a deadlock case where all available
cmdsns have been used for command PDUs which need
additional Data-OUT PDUs to succeed (e.g. a write16
which is larger than first_burst_len).
In this case the target will never increase the maxcmdsn
leading to a deadlock in iscsi_write_to_socket().
If we receive the R2T for such a write request we will
queue the Data-OUT PDUs but at the end of queue. As
a result they will never be sent as the outqueue is already
stuck.
We fix this by sorting the outqueue by ascending itt.
Signed-off-by: Peter Lieven <pl@kamp.de>
This finally makes T1040 trigger the cmdsn overflow deadlock.
Its a bad idea to mangle on negotiated parameters as this leads
to protocol errors.
We also need to avoid overlapping writes as this leads also
to protocol errors.
Additionally we test with and with (if available) immediate data.
Signed-off-by: Peter Lieven <pl@kamp.de>
RFC3720 says that cmdsn comparison must be done using
serial32 arithmetic. This will definetly avoid a deadlock
if cmdsn wraps from 2^32-1 to 0.
Signed-off-by: Peter Lieven <pl@kamp.de>
Change iscsi_scsi_command_async() to write data-out using iovectors
attached to the scsi task structure instead of copying the data into
the buffer holding the header.
Still allow passing the data via an argument to the funtcion so that the
ABI does not change but then just conver the data to an iovector.
Update the write_to_socket functions to know about the iovectors and write them
as part of the pdu.
Convert write10_task to use iovectors.
This will allow 'zero-copy' writes through libiscsi.
However, as 'zero-copy writes does mean that we do more send() calls into
the kernel this may degrade performance for very small i/o.
A scsi write will not take at least 2 send() calls.
One send call for the iscsi header structure and a second send call for the
payload data.
This will be more expensive than the old memcpy() of payload data plus one send() call since the send() will be a lot more expensive than memcpy() of a small amount of data.
If a process opens more than once connection the interfaces are assigned
round-robin from the available ones. However, different processes will
uses a random interface of as starting point. This patch will also
make the redirect case handled correctly.
This patch adds a wrapper around all memory allocations and frees.
The idea is to get warned immediately if the application leaks memory.
Additionally the wrapper functions make it easy to add different
memory allocators or memory pools in the future.
Quoth gcc-4.6.3:
libtool: compile: gcc -DHAVE_CONFIG_H -I. -I. -I./include "-D_U_=__attribute__((unused))" -Wall -W -Wshadow -Wstrict-prototypes -Wpointer-arith -Wcast-align -Wwrite-strings -g -O2 -MT lib/socket.lo -MD -MP -MF lib/.deps/socket.Tpo -c lib/socket.c -fPIC -DPIC -o lib/.libs/socket.o
lib/socket.c:445:1: warning: 'inline' is not at beginning of declaration [-Wold-style-declaration]
Fix this and make it a static function.
Also remove trailing whitespace from this file while at it.
Signed-off-by: Arne Redlich <arne.redlich@googlemail.com>
Send a large number of DATA-OUT PDUs that do not have a matching SCSI-COMMAND
PDU and verify that the target responds correctly. Either by terminating the
session or by just ignoring the data.
Verify also that the target is not "surprised" and crashes.
Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
qemu-kvm/qemu-img starts in+out polls from the socket before the connection is
established. This leads to a hang if the connection cant be established
(i.e. the target is down when qemu-kvm is started).
before:
LIBISCSI_DEBUG=2 qemu-img convert -f iscsi -O raw iscsi://127.0.0.1/iqn.2004-04.com.qnap:ts-809u:iscsi.lieven20.c53dac/0 /dev/null
libiscsi: connecting to portal 127.0.0.1 [iqn.2004-04.com.qnap:ts-809u:iscsi.lieven20.c53dac]
libiscsi: read from socket failed, errno:111 [iqn.2004-04.com.qnap:ts-809u:iscsi.lieven20.c53dac]
libiscsi: connection to 127.0.0.1 established [iqn.2004-04.com.qnap:ts-809u:iscsi.lieven20.c53dac]
->success!!
after:
LIBISCSI_DEBUG=1 qemu-img convert -f iscsi -O raw iscsi://127.0.0.1/iqn.2004-04.com.qnap:ts-809u:iscsi.lieven20.c53dac/0 /dev/null
libiscsi: iscsi_service: socket error Connection refused(111) while connecting. [iqn.2004-04.com.qnap:ts-809u:iscsi.lieven20.c53dac]
libiscsi: Failed to connect to iSCSI socket. iscsi_service: socket error Connection refused(111) while connecting. [iqn.2004-04.com.qnap:ts-809u:iscsi.lieven20.c53dac]
qemu-img: iSCSI: Failed to connect to LUN : Failed to connect to iSCSI socket. iscsi_service: socket error Connection refused(111) while connecting.
qemu-img: Could not open 'iscsi://127.0.0.1/iqn.2004-04.com.qnap:ts-809u:iscsi.lieven20.c53dac/0': Invalid argument
qemu-img: Could not open 'iscsi://127.0.0.1/iqn.2004-04.com.qnap:ts-809u:iscsi.lieven20.c53dac/0'
This patch adds support for setting TCP_SYNCNT to overwrite
the system default values. This allows indirect support
for a configurable connect timeout.
Linux uses a exponential backoff for SYN retries starting
with 1 second.
This means for a value n for TCP_SYNCNT, the connect will
effectively timeout after 2^(n+1)-1 seconds.
This patch adds 3 functions to set the 3 keepalive values TCP_KEEPIDLE, TCP_KEEPCNT
and TCP_KEEPINTVL. The values have to be set after iscsi context creation and are
then configured on the socket on each new connection.
For TCP_USER_TIMEOUT to work it seems to be necessary that SO_KEEPALIVE is
enabled. RFC5482 section 4.2 also says that the TCP_USER_TIMEOUT has to be
less than the keepalive timeout. This means less than 30000 ms in the
current libiscsi default settings for TCP keepalives.
This patch adds a user configurable option to set the TCP_USER_TIMEOUT
socket option. With this timeout set a broken TCP session is shutdown
after a given timeout even there are unacked packets. SO_KEEPALIVE
seems not to work in this case.
Set only the (socket) options which are defined on a given platform.
The function becomes a no-op if no option is known at complie time.
Remove autoconf test for HAVE_TCP_KEEPALIVE too.
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
no data to read from the socket and there is no error.
For this case, if FIONREAD tells us that there are 0 bytes to read, check if
there is a socket error and return ok/error based on that.
Some eventsystems may cause this to burn some cpu if the socket is ok
but there are no bytes available to read by invoking POLLIN over and over, but it is better than failing the application.
