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author | Sage Weil <sage@newdream.net> | 2010-11-04 11:05:05 -0700 |
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committer | Sage Weil <sage@newdream.net> | 2010-11-08 07:29:05 -0800 |
commit | cd045cb42a266882ac24bc21a3a8d03683c72954 (patch) | |
tree | 2938560e8362804e829cc9feb23ef746d354140b /fs/ceph/inode.c | |
parent | feb4cc9bb433bf1491ac5ffbba133f3258dacf06 (diff) | |
download | linux-3.10-cd045cb42a266882ac24bc21a3a8d03683c72954.tar.gz linux-3.10-cd045cb42a266882ac24bc21a3a8d03683c72954.tar.bz2 linux-3.10-cd045cb42a266882ac24bc21a3a8d03683c72954.zip |
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/inode.c')
-rw-r--r-- | fs/ceph/inode.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index 0a49ffde5bc..5a9f907b805 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -1394,11 +1394,8 @@ static void ceph_invalidate_work(struct work_struct *work) spin_lock(&inode->i_lock); dout("invalidate_pages %p gen %d revoking %d\n", inode, ci->i_rdcache_gen, ci->i_rdcache_revoking); - if (ci->i_rdcache_gen == 0 || - ci->i_rdcache_revoking != ci->i_rdcache_gen) { - BUG_ON(ci->i_rdcache_revoking > ci->i_rdcache_gen); + if (ci->i_rdcache_revoking != ci->i_rdcache_gen) { /* nevermind! */ - ci->i_rdcache_revoking = 0; spin_unlock(&inode->i_lock); goto out; } @@ -1408,15 +1405,16 @@ static void ceph_invalidate_work(struct work_struct *work) ceph_invalidate_nondirty_pages(inode->i_mapping); spin_lock(&inode->i_lock); - if (orig_gen == ci->i_rdcache_gen) { + if (orig_gen == ci->i_rdcache_gen && + orig_gen == ci->i_rdcache_revoking) { dout("invalidate_pages %p gen %d successful\n", inode, ci->i_rdcache_gen); - ci->i_rdcache_gen = 0; - ci->i_rdcache_revoking = 0; + ci->i_rdcache_revoking--; check = 1; } else { - dout("invalidate_pages %p gen %d raced, gen now %d\n", - inode, orig_gen, ci->i_rdcache_gen); + dout("invalidate_pages %p gen %d raced, now %d revoking %d\n", + inode, orig_gen, ci->i_rdcache_gen, + ci->i_rdcache_revoking); } spin_unlock(&inode->i_lock); |