On Mon, Feb 10 2025, Bernd Schubert wrote: > On 2/10/25 11:48, Luis Henriques wrote: >> [re-sending -- for some reason I did a simple 'reply', not a 'reply-all'.] >> >> On Mon, Feb 10 2025, Bernd Schubert wrote: >> >>> On 2/10/25 10:48, Luis Henriques wrote: >>>> Currently userspace is able to notify the kernel to invalidate the cache for >>>> an inode. This means that, if all the inodes in a filesystem need to be >>>> invalidated, then userspace needs to iterate through all of them and do this >>>> kernel notification separately. >>>> >>>> This patch adds a new option that allows userspace to invalidate all the >>>> inodes with a single notification operation. In addition to invalidate all >>>> the inodes, it also shrinks the sb dcache. >>>> >>>> Signed-off-by: Luis Henriques <luis@xxxxxxxxxx> >>>> --- >>>> Hi! >>>> >>>> As suggested by Bernd, this patch v2 simply adds an helper function that >>>> will make it easier to replace most of it's code by a call to function >>>> super_iter_inodes() when Dave Chinner's patch[1] eventually gets merged. >>>> >>>> [1] https://lore.kernel.org/r/20241002014017.3801899-3-david@xxxxxxxxxxxxx >>>> >>>> fs/fuse/inode.c | 59 +++++++++++++++++++++++++++++++++++++++ >>>> include/uapi/linux/fuse.h | 3 ++ >>>> 2 files changed, 62 insertions(+) >>>> >>>> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c >>>> index e9db2cb8c150..be51b53006d8 100644 >>>> --- a/fs/fuse/inode.c >>>> +++ b/fs/fuse/inode.c >>>> @@ -547,6 +547,62 @@ struct inode *fuse_ilookup(struct fuse_conn *fc, u64 nodeid, >>>> return NULL; >>>> } >>>> >>>> +static void inval_single_inode(struct inode *inode, struct fuse_conn *fc) >>>> +{ >>>> + struct fuse_inode *fi; >>>> + >>>> + fi = get_fuse_inode(inode); >>>> + spin_lock(&fi->lock); >>>> + fi->attr_version = atomic64_inc_return(&fc->attr_version); >>>> + spin_unlock(&fi->lock); >>>> + fuse_invalidate_attr(inode); >>>> + forget_all_cached_acls(inode); >>> >>> >>> Thank you, much easier to read. >>> >>> Could fuse_reverse_inval_inode() call into this? >> >> Yep, it could indeed. I'll do that in the next iteration, thanks! >> >>> What are the semantics >>> for invalidate_inode_pages2_range() in this case? Totally invalidate? >>> No page cache invalidation at all as right now? If so, why? >> >> So, if I change fuse_reverse_inval_inode() to use this help, it will still >> need to keep the call to invalidate_inode_pages2_range(). But in the new >> function fuse_reverse_inval_all(), I'm not doing it explicitly. Instead, >> that function calls into shrink_dcache_sb(). I *think* that by doing so >> the invalidation will eventually happen. Or am I wrong assuming that? > > I think it will drop it, if the dentry cache is the last user/reference > of the inode. My issue is that it changes semantics a bit - without > FUSE_INVAL_ALL_INODES the page cache is invalidated based on the given > offset. Obviously we cannot give the offset for all inodes, but we > at least document the different semantics in a comment above > FUSE_INVAL_ALL_INODES? Sorry, should have asked earlier for it, just > busy with multiple things in parallel... Yep, that makes sense. In fact, my initial approach was to add a completely different API with a FUSE_NOTIFY_INVAL_INODE_ALL operation. But then I realized that I could simply hijack FUSE_NOTIFY_INVAL_INODE. This would make things a lot easier, specially in the userspace side -- libfuse could even be used without *any* change at all. (Obviously, I expect to send a PR with the new flag and some documentation once this patch is acceptable.) Anyway, I'll also add some comments to this patch. Thanks for your feedback, Bernd. Cheers, -- Luís
