ceph: trim deleted inode

The MDS uses caps message to notify clients about deleted inode.
when receiving a such message, invalidate any alias of the inode.
This makes the kernel release the inode ASAP.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Reviewed-by: Sage Weil <sage@inktank.com>

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 25442b4..430121a 100644 (file)
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2334,6 +2334,38 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
 }
 
 /*
+ * Invalidate unlinked inode's aliases, so we can drop the inode ASAP.
+ */
+static void invalidate_aliases(struct inode *inode)
+{
+       struct dentry *dn, *prev = NULL;
+
+       dout("invalidate_aliases inode %p\n", inode);
+       d_prune_aliases(inode);
+       /*
+        * For non-directory inode, d_find_alias() only returns
+        * connected dentry. After calling d_delete(), the dentry
+        * become disconnected.
+        *
+        * For directory inode, d_find_alias() only can return
+        * disconnected dentry. But directory inode should have
+        * one alias at most.
+        */
+       while ((dn = d_find_alias(inode))) {
+               if (dn == prev) {
+                       dput(dn);
+                       break;
+               }
+               d_delete(dn);
+               if (prev)
+                       dput(prev);
+               prev = dn;
+       }
+       if (prev)
+               dput(prev);
+}
+
+/*
  * Handle a cap GRANT message from the MDS.  (Note that a GRANT may
  * actually be a revocation if it specifies a smaller cap set.)
  *
@@ -2363,6 +2395,7 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
        int writeback = 0;
        int revoked_rdcache = 0;
        int queue_invalidate = 0;
+       int deleted_inode = 0;
 
        dout("handle_cap_grant inode %p cap %p mds%d seq %d %s\n",
             inode, cap, mds, seq, ceph_cap_string(newcaps));
@@ -2407,8 +2440,12 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
                     from_kgid(&init_user_ns, inode->i_gid));
        }
 
-       if ((issued & CEPH_CAP_LINK_EXCL) == 0)
+       if ((issued & CEPH_CAP_LINK_EXCL) == 0) {
                set_nlink(inode, le32_to_cpu(grant->nlink));
+               if (inode->i_nlink == 0 &&
+                   (newcaps & (CEPH_CAP_LINK_SHARED | CEPH_CAP_LINK_EXCL)))
+                       deleted_inode = 1;
+       }
 
        if ((issued & CEPH_CAP_XATTR_EXCL) == 0 && grant->xattr_len) {
                int len = le32_to_cpu(grant->xattr_len);
@@ -2517,6 +2554,8 @@ static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
                ceph_queue_writeback(inode);
        if (queue_invalidate)
                ceph_queue_invalidate(inode);
+       if (deleted_inode)
+               invalidate_aliases(inode);
        if (wake)
                wake_up_all(&ci->i_cap_wq);