ceph: directory operations
Directory operations, including lookup, are defined here. We take advantage of lookup intents when possible. For the most part, we just need to build the proper requests for the metadata server(s) and pass things off to the mds_client. The results of most operations are normally incorporated into the client's cache when the reply is parsed by ceph_fill_trace(). However, if the MDS replies without a trace (e.g., when retrying an update after an MDS failure recovery), some operation-specific cleanup may be needed. We can validate cached dentries in two ways. A per-dentry lease may be issued by the MDS, or a per-directory cap may be issued that acts as a lease on the entire directory. In the latter case, a 'gen' value is used to determine which dentries belong to the currently leased directory contents. We normally prepopulate the dcache and icache with readdir results. This makes subsequent lookups and getattrs avoid any server interaction. It also lets us satisfy readdir operation by peeking at the dcache IFF we hold the per-directory cap/lease, previously performed a readdir, and haven't dropped any of the resulting dentries. Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
parent
355da1eb7a
commit
2817b000b0