similar to: [PATCH libnbd] generator: Fix race condition when validating h->state.

On 6/4/19 6:23 AM, Richard W.M. Jones wrote: > The code for (eg) nbd_aio_pread starts by checking this outside > the lock: > > if (!(nbd_aio_is_ready (h) || nbd_aio_is_processing (h))) { > > However there can still be a race condition even though h->state is > atomic: > > Thread A Thread B > (in a call that holds h->lock)

This works. I'm in the middle of testing whether there is any noticable benefit. Rich.

I need to think about this patch series a bit more, but it does at least pass the tests. Rich.

Rich recently patched things to generate one man page per function rather than libnbd-api.3 (nice), but in doing so got stumped by a problem with a fresh git clone (automake fails for any 'include' directive that does not already exist). I've figured out how to hack around it, but the hack requires GNU make. We already use GNU make constructs elsewhere (such as $(wildcard)), but

On 6/5/19 6:15 AM, Richard W.M. Jones wrote: > For each nbd_(unlocked_)?aio_is_* function, split it into an internal > function that tests the state and a public visible API function. > > For calls within the library, use the internal function. > > This is simple refactoring. > > As a side effect this fixes a race condition identified by Eric Blake: > > Thread A

For each nbd_(unlocked_)?aio_is_* function, split it into an internal function that tests the state and a public visible API function. For calls within the library, use the internal function. This is simple refactoring. As a side effect this fixes a race condition identified by Eric Blake: Thread A Thread B (in a call that holds h->lock) (calling nbd_aio_pread)

v1 was here: https://www.redhat.com/archives/libguestfs/2019-June/thread.html#00055 v2 was here: https://www.redhat.com/archives/libguestfs/2019-June/thread.html#00067 v3: - Fix atomicly -> atomically in commit message. - Fix a comment. - Fix TOCTTOU: There is now an inline function generated called <name>_is_permitted_state, and this is called twice, first outside the

On 6/5/19 6:15 AM, Richard W.M. Jones wrote: > Split h->state into: > > - h->state = the state on entry to the locked region > > - h->next_state = the current state and what the "publicly visible" > state will become when we leave the locked region The rest of this thread discusses potential other names, such as h->public_state for the state visible

Split h->state into: - h->public_state = the state on entry to the locked region This is also the atomicly, publicly visible state. - h->state = the real current state of the handle When we leave the locked region we update h->public_state with h->state, so that from outside the lock the handle appears to move atomically from its previous state to the final state without

This is slightly redundant with just trying nbd_set_tls(nbd, 2) then checking for failure; however, this function does not set errors and looks more similar to nbd_supports_uri. --- This is borderline enough that I figured I'd post it to check if we want it. generator/generator | 45 ++++++++++++++++++++++++++++++++++++++------- interop/interop.c | 4 ++++ lib/handle.c | 12

Patch 1/6 was posted before and I didn't change it: https://www.redhat.com/archives/libguestfs/2019-May/thread.html#00134 That doesn't necessarily mean I shouldn't change it, I'm posting it again because the other patches depend on it. The main change in this series is we add three new API functions: nbd_aio_is_created - connection has just been created

These are some simplifications to the generator. They don't probably make much sense on their own, but they are preparatory to better handling of enums, and or'd lists of flags. Rich.

Place the tracing of return values after any generated 'out:' label, as it is important to see even the errors caused by calling a function in the wrong handle state. Fixes: 9df088bfa9 --- Multiple bugs found today, but only time to submit one patch so far. I found them all while trying to implement .list_exports in nbdkit. Bug 1: 'nbdinfo --list --json $uri' produces invalid

On 8/9/19 7:59 AM, Richard W.M. Jones wrote: > In libguestfs generator we have the concept of optargs which is > different from plain arguments. These are mapped to optional > arguments in languages that support them such as Python. > > This commit adds a new concept of optargs. At the moment it is simply > limited to handling the optional (in some bindings) flags parameter

For commands with long names and/or short descriptors, you can end up going over 72 characters in the first line of the man page (causing podwrapper to complain). Wrap these lines. --- generator/generator | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/generator/generator b/generator/generator index 7d3f656..ad1cb6b 100755 --- a/generator/generator +++ b/generator/generator

Patches 1-4 are basically uncontroversial, straightforward refactoring and IMHO we should just push them. Possibly 1-3 should be squashed together, but I posted them separately so they are easier to review. Patches 5 and 6 together implement OClosure. Patch 5 adds the feature and is simple to understand. Patch 6 changes the Closure completion callbacks into OClosure, but because it doesn't

This patch adds support for symbol versions. It is based on what libvirt does. The generated syms file looks like: LIBNBD_1.0 { global: nbd_...; nbd_...; local: *; }; In a future stable 1.2 release, new symbols would go into a new section which would look like this: LIBNBD_1.2 { global: nbd_new_symbol; nbd_another_new_symbol; local: *; } LIBNBD_1.0; In my testing the

Split h->state into: - h->public_state = the state on entry to the locked region This is also the atomically, publicly visible state. - h->state = the real current state of the handle When we leave the locked region we update h->public_state with h->state, so that from outside the lock the handle appears to move atomically from its previous state to the final state without

Redhat 6.2 kernel 2.2.14-12 Samba 3.0.6 compiled with ./configure --prefix=/usr/local/samba --localstatedir=/var/log/samba --with-lockdir=/var/lock/samba --with-privatedir=/etc/rc-abas.d --with-configdir=/etc/rc-abas.d --enable-debug I can list directories and write files on a samba share but cannot read files. This happens with Windows XP client or smbclient. After downgrading to 3.0.5 samba

Automake insists that any file present in a Makefile.am 'include' must be present, but it has no idea about the GNU make extension 'sinclude'. Use this to our advantage: as long as Makefile.inc has nothing other than variable modifications (done in the previous patch), and our rules properly generate it when needed (thanks to generator_built), then running 'make' will