kclient: drop any unwanted caps when unlinking a file

Since we can't reopen an unlinked file, there's no reason to hold on to
them.  And the MDS will often want to lock to update max_size, which could
mean spurious revocations.  At the very least, make sure we drop the LINK
caps.

Do the same for the rename target, if it exists.

diff --git a/src/kernel/dir.c b/src/kernel/dir.c
index 6c76aa39b5fe421e3937e64070655bfa00495d3d..2710ee0371cccbbbdb681d2dff9870b91e83488e 100644 (file)
--- a/src/kernel/dir.c
+++ b/src/kernel/dir.c
@@ -562,6 +562,23 @@ static int ceph_link(struct dentry *old_dentry, struct inode *dir,
        return err;
 }
 
+/*
+ * For a soon-to-be unlinked file, drop the AUTH_RDCACHE caps.  If it
+ * looks like the link count will hit 0, drop any other caps (other
+ * than PIN) we don't specifically want (due to the file still being
+ * open).
+ */
+static void drop_caps_for_unlink(struct inode *inode)
+{
+       int drop = CEPH_CAP_LINK_RDCACHE | CEPH_CAP_LINK_EXCL;
+
+       spin_lock(&inode->i_lock);
+       if (inode->i_nlink == 1) 
+               drop |= ~(__ceph_caps_wanted(ceph_inode(inode)) | CEPH_CAP_PIN);
+       spin_unlock(&inode->i_lock);
+       ceph_release_caps(inode, drop);
+}
+
 /*
  * rmdir and unlink are differ only by the metadata op code
  */
@@ -598,7 +615,7 @@ static int ceph_unlink(struct inode *dir, struct dentry *dentry)
        if (!ceph_caps_issued_mask(ceph_inode(dir), CEPH_CAP_FILE_EXCL))
                ceph_release_caps(dir, CEPH_CAP_FILE_RDCACHE);
        ceph_mdsc_lease_release(mdsc, dir, dentry, CEPH_LOCK_DN);
-       ceph_release_caps(inode, CEPH_CAP_LINK_RDCACHE);
+       drop_caps_for_unlink(inode);
        err = ceph_mdsc_do_request(mdsc, dir, req);
        if (!err && !req->r_reply_info.head->is_dentry)
                d_delete(dentry);
@@ -635,6 +652,8 @@ static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
        if (!ceph_caps_issued_mask(ceph_inode(new_dir), CEPH_CAP_FILE_EXCL))
                ceph_release_caps(new_dir, CEPH_CAP_FILE_RDCACHE);
        ceph_mdsc_lease_release(mdsc, new_dir, new_dentry, CEPH_LOCK_DN);
+       if (new_dentry->d_inode)
+               drop_caps_for_unlink(new_dentry->d_inode);
        err = ceph_mdsc_do_request(mdsc, old_dir, req);
        if (!err && !req->r_reply_info.head->is_dentry) {
                /*