similar to: [nbdkit PATCH] noextents: Document use case with tmpfs

Being able to programmatically force nbdkit to be less parallel can be useful during testing. I was less sure about patch 3, but if you like it, I'm inclined to instead squash it into patch 1. This patch is written to apply after my NBD_CMD_CACHE work (since I touched the nocache filter); but can be rearranged if we think this series should go in first while that one undergoes any adjustments

Since v1: - rework .can_cache to be tri-state, with default of no advertisement (ripple effect through other patches) - add a lot more patches in order to round out filter support And in the meantime, Rich pushed NBD_CMD_CACHE support into libnbd, so in theory we now have a way to test cache commands through the entire stack. Eric Blake (24): server: Internal hooks for implementing

When we added support for .extents, we had nbdkit unconditionally support structured replies if the client requests them, and the plugin's .can_extents has no impact on what the server advertises. However, while the plugin API doesn't care whether the client requested SR, there are still integration situations where not advertising SR can be useful (such as comparison on what a client does

When we added support for .extents, we had nbdkit unconditionally support structured replies if the client requests them, and the plugin's .can_extents has no impact on what the server advertises. However, while the plugin API doesn't care whether the client requested SR, there is still a case to be made for allowing a filter to prevent SR, at least for testing purposese (such as

As I've spent really too long today investigating this, I want to document this in a public email, even though there's nothing really that interesting here. One thing you find from search for VDD 6.7 / VixDiskLib_QueryAllocatedBlocks issues with Google is that we must be one of the very few users out there. And the other thing is that it's quite broken. All testing was done using

Similar to the existing fua, nozero and noextents filters, add a filter to make it easy to override the basic caching functionality, in part to facilitate timing tests of whether a plugin's cache implementation is worthwhile. A worthwhile test to add to the testsuite would connect the log filter both before and after the nocache filter, to prove how caching requests are altered. However,

The NBD protocol is adding an extension to let servers advertise initialization state to the client: whether the image contains holes, and whether it is known to read as all zeroes. Most filters just pass through the plugin's result (as it is only checked once when first connecting), but we can do useful things in log (mention the setting), extentlist (answer based on the extents we are

On Fri, Apr 12, 2019 at 03:52:58PM +0200, Martin Kletzander wrote: > On Thu, Apr 11, 2019 at 06:55:55PM +0100, Richard W.M. Jones wrote: > >This seems to be a bug in VDDK, possibly connected with the fact that > >we fork after initializing VDDK but before doing the > >VixDiskLib_ConnectEx. I suspect it's something to do with the PID > >changing. > > >

We documented our intent of only allowing a filter to run with the same version of nbdkit it was compiled against, but up to now, were not actually enforcing that - we had only been insisting on the looser notion of a matching ._api_version, which doesn't help when we've forgotten to bump that macro when making incompatible API/ABI changes (see commit 6934d4c1). However, we can't use

The retry filter defaults to 5 retries, but when run with verbose details produces some confusing output: $ rm -f /tmp/inject; (sleep 5s; touch /tmp/inject)& ./nbdkit -f -v -U - \ null 1G --filter=retry --filter=noextents --filter=error error-rate=100% \ error-file=/tmp/inject --filter=delay rdelay=1 \ --run 'qemu-img convert $nbd out.img' ... nbdkit: null[1]: debug: noextents:

On 4/1/20 5:12 AM, Richard W.M. Jones wrote: > On Tue, Mar 31, 2020 at 04:00:22PM -0500, Eric Blake wrote: >> The retry filter defaults to 5 retries, but when run with verbose >> details produces some confusing output: >> >> $ rm -f /tmp/inject; (sleep 5s; touch /tmp/inject)& ./nbdkit -f -v -U - \ >> null 1G --filter=retry --filter=noextents --filter=error

On Mon, Apr 15, 2019 at 04:30:47PM +0200, Martin Kletzander wrote: > On Fri, Apr 12, 2019 at 04:30:02PM +0100, Richard W.M. Jones wrote: > > +-- nbdkit monitoring process > > | > > +-- first child = nbdkit > > | > > +-- second child = ‘--run’ command > > > >so when the second child exits, the monitoring process (which is doing > >nothing

I will be following up to this email with four separate threads each addressed to the appropriate single list, with proposed changes to: - the NBD protocol - qemu: both server and client - libnbd: client - nbdkit: server The feature in question adds a new optional NBD_INFO_ packet to the NBD_OPT_GO portion of handshake, adding up to 16 bits of information that the server can advertise to the

This is a cover letter to a series of patches being proposed in tandem to four different projects: - nbd: Document a new NBD_CMD_FLAG_FAST_ZERO command flag - qemu: Implement the flag for both clients and server - libnbd: Implement the flag for clients - nbdkit: Implement the flag for servers, including the nbd passthrough client If you want to test the patches together, I've pushed a

No need for filters to specify their model in two different ways; the callback alone is sufficient. Since all filters are in-tree, we can deal with the API/ABI change made here. Signed-off-by: Eric Blake <eblake@redhat.com> --- docs/nbdkit-filter.pod | 48 +++++++++++++++------------------ include/nbdkit-filter.h | 6 ++--- filters/cow/cow.c | 2 --

I still need to add testsuite coverage. Perhaps it might be easier if I create a new '--filter=log logfile=foo' filter that produces a log of which commands a client sent, then compare the log using a known client that uses write_zeroes (qemu-io works well) both with and without --filter=nozero to prove that the change in advertisement changes the commands sent over the wire (that would

It may be useful to test whether the client's use of NBD_CMD_FLAG_NO_HOLE makes a difference; do this by adding a mode to --filter=nozero to force a non-trimming zero write. Signed-off-by: Eric Blake <eblake@redhat.com> --- filters/nozero/nbdkit-nozero-filter.pod | 19 +++++++---- filters/nozero/nozero.c | 45 ++++++++++++++++++++----- tests/test-nozero.sh

This creates libnbdkit.so as discussed in the following thread: https://www.redhat.com/archives/libguestfs/2020-March/thread.html#00203 test-delay-shutdown.sh fails for unclear reasons. This series starts by reverting "tests: Don't strand hung nbdkit processes" which is because several other tests fail randomly unless I revert this patch. I didn't investigate this yet so it

Remove the need to use file= (and in future other) parameters for many plugins. eg. Using the file plugin becomes: nbdkit file disk.img Rich.

v1 was here: https://www.redhat.com/archives/libguestfs/2018-September/msg00024.html v2: - As discussed in the patch review, tighten up the characters permitted in keys. - Update documentation to note that relative paths can be made safe by prefixing with ./ and absolute paths do not need any extra steps. - I pushed patch 1/6 from the v1 series since it was just a trivial