From cd045cb42a266882ac24bc21a3a8d03683c72954 Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Thu, 4 Nov 2010 11:05:05 -0700 Subject: ceph: fix rdcache_gen usage and invalidate We used to use rdcache_gen to indicate whether we "might" have cached pages. Now we just look at the mapping to determine that. However, some old behavior remains from that transition. First, rdcache_gen == 0 no longer means we have no pages. That can happen at any time (presumably when we carry FILE_CACHE). We should not reset it to zero, and we should not check that it is zero. That means that the only purpose for rdcache_revoking is to resolve races between new issues of FILE_CACHE and an async invalidate. If they are equal, we should invalidate. On success, we decrement rdcache_revoking, so that it is no longer equal to rdcache_gen. Similarly, if we success in doing a sync invalidate, set revoking = gen - 1. (This is a small optimization to avoid doing unnecessary invalidate work and does not affect correctness.) Signed-off-by: Sage Weil --- fs/ceph/caps.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/ceph/caps.c') diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 04b207b0c842..60d27bc9eb83 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -1430,8 +1430,8 @@ static int try_nonblocking_invalidate(struct inode *inode) invalidating_gen == ci->i_rdcache_gen) { /* success. */ dout("try_nonblocking_invalidate %p success\n", inode); - ci->i_rdcache_gen = 0; - ci->i_rdcache_revoking = 0; + /* save any racing async invalidate some trouble */ + ci->i_rdcache_revoking = ci->i_rdcache_gen - 1; return 0; } dout("try_nonblocking_invalidate %p failed\n", inode); -- cgit v1.2.3