bwlp/qemu.git/nbd/trace-events, branch spice_video_codecs

nbd: trace long NBD operations

2022-06-29T07:57:02+00:00

At the moment there are 2 sources of lengthy operations if configured: * open connection, which could retry inside and * reconnect of already opened connection These operations could be quite lengthy and cumbersome to catch thus it would be quite natural to add trace points for them. This patch is based on the original downstream work made by Vladimir. Signed-off-by: Denis V. Lunev CC: Eric Blake CC: Vladimir Sementsov-Ogievskiy CC: Kevin Wolf CC: Hanna Reitz CC: Paolo Bonzini Reviewed-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Vladimir Sementsov-Ogievskiy

docs: fix references to docs/devel/tracing.rst

2021-06-02T04:51:09+00:00

Commit e50caf4a5c ("tracing: convert documentation to rST") converted docs/devel/tracing.txt to docs/devel/tracing.rst. We still have several references to the old file, so let's fix them with the following command: sed -i s/tracing.txt/tracing.rst/ $(git grep -l docs/devel/tracing.txt) Signed-off-by: Stefano Garzarella Reviewed-by: Philippe Mathieu-Daudé Message-Id: <20210517151702.109066-2-sgarzare@redhat.com> Signed-off-by: Thomas Huth

trace: Remove trailing newline in events

2019-09-18T09:19:47+00:00

While the tracing framework does not forbid trailing newline in events format string, using them lead to confuse output. It is the responsibility of the backend to properly end an event line. Some of our formats have trailing newlines, remove them. [Fixed typo in commit description reported by Eric Blake --Stefan] Reviewed-by: John Snow Reviewed-by: Kevin Wolf Signed-off-by: Philippe Mathieu-Daudé Message-id: 20190916095121.29506-2-philmd@redhat.com Message-Id: <20190916095121.29506-2-philmd@redhat.com> Signed-off-by: Stefan Hajnoczi

nbd: Tolerate more errors to structured reply request

2019-09-05T20:57:37+00:00

A server may have a reason to reject a request for structured replies, beyond just not recognizing them as a valid request; similarly, it may have a reason for rejecting a request for a meta context. It doesn't hurt us to continue talking to such a server; otherwise 'qemu-nbd --list' of such a server fails to display all available details about the export. Encountered when temporarily tweaking nbdkit to reply with NBD_REP_ERR_POLICY. Present since structured reply support was first added (commit d795299b reused starttls handling, but starttls is different in that we can't fall back to other behavior on any error). Note that for an unencrypted client trying to connect to a server that requires encryption, this defers the point of failure to when we finally execute a strict command (such as NBD_OPT_GO or NBD_OPT_LIST), now that the intermediate NBD_OPT_STRUCTURED_REPLY does not diagnose NBD_REP_ERR_TLS_REQD as fatal; but as the protocol eventually gets us to a command where we can't continue onwards, the changed error message doesn't cause any security concerns. Signed-off-by: Eric Blake Message-Id: <20190824172813.29720-3-eblake@redhat.com> Reviewed-by: Daniel P. Berrangé [eblake: fix iotest 233]

nbd/server: Trace client noncompliance on unaligned requests

2019-04-08T18:42:24+00:00

We've recently added traces for clients to flag server non-compliance; let's do the same for servers to flag client non-compliance. According to the spec, if the client requests NBD_INFO_BLOCK_SIZE, it is promising to send all requests aligned to those boundaries. Of course, if the client does not request NBD_INFO_BLOCK_SIZE, then it made no promises so we shouldn't flag anything; and because we are willing to handle clients that made no promises (the spec allows us to use NBD_REP_ERR_BLOCK_SIZE_REQD if we had been unwilling), we already have to handle unaligned requests (which the block layer already does on our behalf). So even though the spec allows us to return EINVAL for clients that promised to behave, it's easier to always answer unaligned requests. Still, flagging non-compliance can be useful in debugging a client that is trying to be maximally portable. Qemu as client used to have one spot where it sent non-compliant requests: if the server sends an unaligned reply to NBD_CMD_BLOCK_STATUS, and the client was iterating over the entire disk, the next request would start at that unaligned point; this was fixed in commit a39286dd when the client was taught to work around server non-compliance; but is equally fixed if the server is patched to not send unaligned replies in the first place (yes, qemu 4.0 as server still has few such bugs, although they will be patched in 4.1). Fortunately, I did not find any more spots where qemu as client was non-compliant. I was able to test the patch by using the following hack to convince qemu-io to run various unaligned commands, coupled with serving 512-byte alignment by intentionally omitting '-f raw' on the server while viewing server traces. | diff --git i/nbd/client.c w/nbd/client.c | index 427980bdd22..1858b2aac35 100644 | --- i/nbd/client.c | +++ w/nbd/client.c | @@ -449,6 +449,7 @@ static int nbd_opt_info_or_go(QIOChannel *ioc, uint32_t opt, | nbd_send_opt_abort(ioc); | return -1; | } | + info->min_block = 1;//hack | if (!is_power_of_2(info->min_block)) { | error_setg(errp, "server minimum block size %" PRIu32 | " is not a power of two", info->min_block); Signed-off-by: Eric Blake Message-Id: <20190403030526.12258-3-eblake@redhat.com> [eblake: address minor review nits] Reviewed-by: Vladimir Sementsov-Ogievskiy

trace-events: Delete unused trace points

2019-03-22T16:18:07+00:00

Tracked down with cleanup-trace-events.pl. Funnies requiring manual post-processing: * block.c and blockdev.c trace points are in block/trace-events. * hw/block/nvme.c uses the preprocessor to hide its trace point use from cleanup-trace-events.pl. * include/hw/xen/xen_common.h trace points are in hw/xen/trace-events. * net/colo-compare and net/filter-rewriter.c use pseudo trace points colo_compare_udp_miscompare and colo_filter_rewriter_debug to guard debug code. Signed-off-by: Markus Armbruster Message-id: 20190314180929.27722-5-armbru@redhat.com Message-Id: <20190314180929.27722-5-armbru@redhat.com> Signed-off-by: Stefan Hajnoczi

trace-events: Shorten file names in comments

2019-03-22T16:18:07+00:00

We spell out sub/dir/ in sub/dir/trace-events' comments pointing to source files. That's because when trace-events got split up, the comments were moved verbatim. Delete the sub/dir/ part from these comments. Gets rid of several misspellings. Signed-off-by: Markus Armbruster Reviewed-by: Philippe Mathieu-Daudé Message-id: 20190314180929.27722-3-armbru@redhat.com Message-Id: <20190314180929.27722-3-armbru@redhat.com> Signed-off-by: Stefan Hajnoczi

trace-events: Consistently point to docs/devel/tracing.txt

2019-03-22T16:17:37+00:00

Almost all trace-events point to docs/devel/tracing.txt in a comment right at the beginning. Touch up the ones that don't. [Updated with Markus' new commit description wording. --Stefan] Signed-off-by: Markus Armbruster Reviewed-by: Philippe Mathieu-Daudé Message-id: 20190314180929.27722-2-armbru@redhat.com Message-Id: <20190314180929.27722-2-armbru@redhat.com> Signed-off-by: Stefan Hajnoczi

nbd/client: Refactor nbd_opt_go() to support NBD_OPT_INFO

2019-01-21T21:49:52+00:00

Rename the function to nbd_opt_info_or_go() with an added parameter and slight changes to comments and trace messages, in order to reuse the function for NBD_OPT_INFO. Signed-off-by: Eric Blake Message-Id: <20190117193658.16413-17-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy

nbd/client: Split handshake into two functions

2019-01-21T21:49:52+00:00

An upcoming patch will add the ability for qemu-nbd to list the services provided by an NBD server. Share the common code of the TLS handshake by splitting the initial exchange into a separate function, leaving only the export handling in the original function. Functionally, there should be no change in behavior in this patch, although some of the code motion may be difficult to follow due to indentation changes (view with 'git diff -w' for a smaller changeset). I considered an enum for the return code coordinating state between the two functions, but in the end just settled with ample comments. Signed-off-by: Eric Blake Reviewed-by: Richard W.M. Jones Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <20190117193658.16413-15-eblake@redhat.com>