From 621e155a3591962420eacdd39f6f0aa29ceb221e Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:49:27 +1100 Subject: fs: change d_compare for rcu-walk Change d_compare so it may be called from lock-free RCU lookups. This does put significant restrictions on what may be done from the callback, however there don't seem to have been any problems with in-tree fses. If some strange use case pops up that _really_ cannot cope with the rcu-walk rules, we can just add new rcu-unaware callbacks, which would cause name lookup to drop out of rcu-walk mode. For in-tree filesystems, this is just a mechanical change. Signed-off-by: Nick Piggin --- Documentation/filesystems/porting | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'Documentation/filesystems/porting') diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 9e71c9ad3108..d44511e20828 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -326,3 +326,10 @@ to it. unreferenced dentries, and is now only called when the dentry refcount goes to 0. Even on 0 refcount transition, it must be able to tolerate being called 0, 1, or more times (eg. constant, idempotent). + +--- +[mandatory] + + .d_compare() calling convention and locking rules are significantly +changed. Read updated documentation in Documentation/filesystems/vfs.txt (and +look at examples of other filesystems) for guidance. -- cgit v1.2.3-59-g8ed1b