diff options
| author | Sage Weil <sage@newdream.net> | 2010-11-04 11:05:05 -0700 |
|---|---|---|
| committer | Sage Weil <sage@newdream.net> | 2010-11-08 07:29:05 -0800 |
| commit | cd045cb42a266882ac24bc21a3a8d03683c72954 (patch) | |
| tree | 2938560e8362804e829cc9feb23ef746d354140b | |
| parent | feb4cc9bb433bf1491ac5ffbba133f3258dacf06 (diff) | |
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>
| -rw-r--r-- | fs/ceph/caps.c | 4 | ||||
| -rw-r--r-- | fs/ceph/inode.c | 16 | ||||
| -rw-r--r-- | fs/ceph/super.h | 4 |
3 files changed, 10 insertions, 14 deletions
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 04b207b0c84..60d27bc9eb8 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); 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); diff --git a/fs/ceph/super.h b/fs/ceph/super.h index 1886294e12f..7f01728a465 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 */ |