ceph: change dentry offset and position after splice_dentry

This fixes a bug, where we had the parent list have dentries with
offsets that are not monotonically increasing, which caused the ceph
dcache_readdir to skip entries.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 8774b28115970b538fa2af043eb7e2ac84aa2570..518beb628f0920afff3b063251ce26a12af46245 100644 (file)
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -816,6 +816,33 @@ out:
        return dn;
 }
 
+/*
+ * Set dentry's directory position based on the current dir's max, and
+ * order it in d_subdirs, so that dcache_readdir behaves.
+ */
+static void ceph_set_dentry_offset(struct dentry *dn)
+{
+       struct dentry *dir = dn->d_parent;
+       struct inode *inode = dn->d_parent->d_inode;
+       struct ceph_dentry_info *di;
+
+       BUG_ON(!inode);
+
+       di = ceph_dentry(dn);
+
+       spin_lock(&inode->i_lock);
+       di->offset = ceph_inode(inode)->i_max_offset++;
+       spin_unlock(&inode->i_lock);
+
+       spin_lock(&dcache_lock);
+       spin_lock(&dn->d_lock);
+       list_move_tail(&dir->d_subdirs, &dn->d_u.d_child);
+       dout("set_dentry_offset %p %lld (%p %p)\n", dn, di->offset,
+            dn->d_u.d_child.prev, dn->d_u.d_child.next);
+       spin_unlock(&dn->d_lock);
+       spin_unlock(&dcache_lock);
+}
+
 /*
  * Incorporate results into the local cache.  This is either just
  * one inode, or a directory, dentry, and possibly linked-to inode (e.g.,
@@ -987,6 +1014,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
                                goto done;
                        }
                        req->r_dentry = dn;  /* may have spliced */
+                       ceph_set_dentry_offset(dn);
                        igrab(in);
                } else if (ceph_ino(in) == vino.ino &&
                           ceph_snap(in) == vino.snap) {
@@ -1029,6 +1057,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
                        err = PTR_ERR(dn);
                        goto done;
                }
+               ceph_set_dentry_offset(dn);
                req->r_dentry = dn;  /* may have spliced */
                igrab(in);
                rinfo->head->is_dentry = 1;  /* fool notrace handlers */