On Wed, 2024-05-15 at 20:51 +0800, libaokun@xxxxxxxxxxxxxxx wrote: > From: Baokun Li <libaokun1@xxxxxxxxxx> > > Hi all! > > This is the second version of this patch series. Thank you, Jia Zhu and > Gao Xiang, for the feedback in the previous version. > > We've been testing ondemand mode for cachefiles since January, and we're > almost done. We hit a lot of issues during the testing period, and this > patch set fixes some of the issues related to reopen worker/send req/poll. > The patches have passed internal testing without regression. > > Patch 1-3: A read request waiting for reopen could be closed maliciously > before the reopen worker is executing or waiting to be scheduled. So > ondemand_object_worker() may be called after the info and object and even > the cache have been freed and trigger use-after-free. So use > cancel_work_sync() in cachefiles_ondemand_clean_object() to cancel the > reopen worker or wait for it to finish. Since it makes no sense to wait > for the daemon to complete the reopen request, to avoid this pointless > operation blocking cancel_work_sync(), Patch 1 avoids request generation > by the DROPPING state when the request has not been sent, and Patch 2 > flushes the requests of the current object before cancel_work_sync(). > > Patch 4: Cyclic allocation of msg_id to avoid msg_id reuse misleading > the daemon to cause hung. > > Patch 5: Hold xas_lock during polling to avoid dereferencing reqs causing > use-after-free. This issue was triggered frequently in our tests, and we > found that anolis 5.10 had fixed it, so to avoid failing the test, this > patch was pushed upstream as well. > > Comments and questions are, as always, welcome. > Please let me know what you think. > > Thanks, > Baokun > > Changes since v1: > * Collect RVB from Jia Zhu and Gao Xiang.(Thanks for your review!) > * Pathch 1,2：Add more commit messages. > * Pathch 3：Add Fixes tag as suggested by Jia Zhu. > * Pathch 4：No longer changing "do...while" to "retry" to focus changes > and optimise commit messages. > * Pathch 5: Drop the internal RVB tag. > > [V1]: https://lore.kernel.org/all/20240424033409.2735257-1-libaokun@xxxxxxxxxxxxxxx > > Baokun Li (3): > cachefiles: stop sending new request when dropping object > cachefiles: flush all requests for the object that is being dropped > cachefiles: cyclic allocation of msg_id to avoid reuse > > Hou Tao (1): > cachefiles: flush ondemand_object_worker during clean object > > Jingbo Xu (1): > cachefiles: add missing lock protection when polling > > fs/cachefiles/daemon.c | 4 ++-- > fs/cachefiles/internal.h | 3 +++ > fs/cachefiles/ondemand.c | 52 +++++++++++++++++++++++++++++++++++----- > 3 files changed, 51 insertions(+), 8 deletions(-) > The set itself looks fairly straightforward, but I don't know this code well enough to give it a proper review. Acked-by: Jeff Layton <jlayton@xxxxxxxxxx>
