[LTP] [PATCH] fanotify10: Calling drop_cache twice to ensure the inode is evicted

[Petr Vorel]

Hi all,

> On Tue 03-09-24 16:08:07, Petr Vorel wrote:
> > Hi all,

> > > In this test case, some scenarios are designed to verify whether the
> > > FANOTIFY_EVICTABLE flag takes effect: by verifying that information cannot
> > > be obtained from the corresponding inode after drop_cache, as this flag
> > > does not ping the inode.

> > > However, drop_cache is only performed once here, which may result in the
> > > inode not being released in NUMA scenarios. Suppose the inode is located
> > > on NUMA0 and the dentry is located on NUMA1; the first drop_cache can only
> > > ensure that the inode is added to the LRU list, but does not guarantee that
> > > evict() can been called because dispose_list does not yet include this
> > > inode when traversing NUMA0, which causes the testcase execution fail.

> > I wonder if there can be some detection that inode is evicted.
> > Or, can it happen that even 2x drop is not enough?

> > > For the single-file scenario in this testcase, executing drop_cache twice
> > > is necessary to ensure the inode is evicted, thus allowing the testcase to
> > > pass.

> > Acked-by: Petr Vorel <pvorel@suse.cz>

> > @Amir, Jan, could you please have a look?

> Yeah, as Amir wrote, I've ended up doing similar thing for fanotify23 so:

My bad memory (8ccf5b45cc), thanks for reminder and your review.
I checked only these two fanotify tests are dropping caches.

Merged.

Kind regards,
Petr