qemu-e2k/nbd
Eric Blake ebd57062a1 nbd: Simplify meta-context parsing
We had a premature optimization of trying to read as little from the
wire as possible while handling NBD_OPT_SET_META_CONTEXT in phases.
But in reality, we HAVE to read the entire string from the client
before we can get to the next command, and it is easier to just read
it all at once than it is to read it in pieces.  And once we do that,
several functions end up no longer performing I/O, so they can drop
length and errp parameters, and just return a bool instead of
modifying through a pointer.

Our iotests still pass; I also checked that libnbd's testsuite (which
covers more corner cases of odd meta context requests) still passes.
There are cases where the sequence of trace messages produced differs
(for example, when no bitmap is exported, a query for "qemu:" now
produces two trace lines instead of one), but trace points are for
debug and have no effect on what the client sees.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200930121105.667049-4-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[eblake: enhance commit message]
Signed-off-by: Eric Blake <eblake@redhat.com>
2020-10-09 15:05:08 -05:00
..
client.c nbd: Use ERRP_GUARD() 2020-07-10 15:18:09 +02:00
common.c nbd: Prepare for NBD_CMD_FLAG_FAST_ZERO 2019-09-05 16:03:13 -05:00
meson.build meson: convert block 2020-08-21 06:30:18 -04:00
nbd-internal.h Include qemu/main-loop.h less 2019-08-16 13:31:52 +02:00
server.c nbd: Simplify meta-context parsing 2020-10-09 15:05:08 -05:00
trace-events trace: Remove trailing newline in events 2019-09-18 10:19:47 +01:00
trace.h trace: switch position of headers to what Meson requires 2020-08-21 06:18:24 -04:00