Am 19.01.2024 um 17:29 hat Ari Sundholm geschrieben: > During the review of a fix for a concurrency issue in blklogwrites, > it was found that the driver needs an additional fix when enabling > multiqueue, which is a new feature introduced in QEMU 9.0, as the > driver state may be read and written by multiple threads at the same > time, which was not the case when the driver was originally written. > > Fix the multi-threaded scenario by introducing a mutex to protect the > mutable fields in the driver state, and always having the mutex locked > by the current thread when accessing them. Also use the mutex and a > CoQueue to ensure that the super block is not being written to by > multiple threads concurrently and updates are properly serialized. > > Additionally, add the const qualifier to a few BDRVBlkLogWritesState > pointer targets in contexts where the driver state is not written to. > > Signed-off-by: Ari Sundholm <a...@tuxera.com> > > v1->v2: Ensure that the super block is not written to concurrently. > v2->v3: Use a CoQueue instead of a condition variable, as the latter > does not make the currently executing coroutine yield on entering a > wait. > --- > block/blklogwrites.c | 85 +++++++++++++++++++++++++++++++++++++++----- > 1 file changed, 77 insertions(+), 8 deletions(-)
For your next series, please put the changelog between versions below the "---" marker so that git am doesn't consider it part of the commit message. Thanks, applied to the block branch. Kevin
