On 02/23/2017 08:00 PM, Frank Filz wrote: >> I have a first pass that works and passes pynfs! It isn't quite correct in > that a >> rename into a directory or a create doesn't invalidate the dirent cache > and >> thus a readdir might not show the new file. >> >> Unlink and rename out of a directory need not invalidate and should work >> properly. >> >> Also left to do is memory management to constrain the total number of >> dirents. >> >> The inode cache LRU reclaims the least recently used entry, however that >> would cause problems for dirents since to reclaim one, we must hold the >> content lock on the containing directory, but we also hold the content > lock on >> the directory that needs another dirent. If the two directories happen to > be >> involved in a rename from one directory to another, the order could be >> reversed and create a deadlock. >> >> Another option is to have the LRU thread dispose of dirents from the least >> recently used directories the same way it disposes of open global file >> descriptors. That combined with logic that switched to uncached mode if we >> couldn't get a free dirent would allow a reasonable mechanism. >> >> Anyway, I encourage folks who are interested to take a look at the WIP > code >> and play with it. > > And now directory invalidation is enabled for create, link, and rename. > > I think this is pretty close to complete. > > Please have at it, we will torture it at Connectathon next week. > > If we can gain a reasonable confidence, we can merge it this week, though > that doesn't give people much time to review... > > It can be disabled by setting Dir_Chunk to 0 in the CacheInode config block. > > Still to be decided is how to interact with disabling dirent cache. > Currently, with chunking enabled, we will never skip caching. Also, do we > want to keep the legacy dirent cache? > > One proposal is to dump the legacy cache, and if Dir_Chunk is 0 then don't > cache.
I don't think we should ultimately keep both cache types. For now, while we're testing, it's fine, but I think we should remove the old cache once we have confidence in the chunked cache. Daniel ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Nfs-ganesha-devel mailing list Nfs-ganesha-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs-ganesha-devel
