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authorSage Weil <sage@newdream.net>2010-11-04 11:05:05 -0700
committerSage Weil <sage@newdream.net>2010-11-08 07:29:05 -0800
commitcd045cb42a266882ac24bc21a3a8d03683c72954 (patch)
tree2938560e8362804e829cc9feb23ef746d354140b /fs/ceph/super.h
parentfeb4cc9bb433bf1491ac5ffbba133f3258dacf06 (diff)
downloadlinux-cd045cb42a266882ac24bc21a3a8d03683c72954.tar.bz2
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 <sage@newdream.net>
Diffstat (limited to 'fs/ceph/super.h')
-rw-r--r--fs/ceph/super.h4
1 files changed, 1 insertions, 3 deletions
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 1886294e12f7..7f01728a4657 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -293,9 +293,7 @@ struct ceph_inode_info {
int i_rd_ref, i_rdcache_ref, i_wr_ref;
int i_wrbuffer_ref, i_wrbuffer_ref_head;
u32 i_shared_gen; /* increment each time we get FILE_SHARED */
- u32 i_rdcache_gen; /* we increment this each time we get
- FILE_CACHE. If it's non-zero, we
- _may_ have cached pages. */
+ u32 i_rdcache_gen; /* incremented each time we get FILE_CACHE. */
u32 i_rdcache_revoking; /* RDCACHE gen to async invalidate, if any */
struct list_head i_unsafe_writes; /* uncommitted sync writes */