ocfs2: invalidate dentry if its dentry_lock isn't initialized.

In commit a5a0a630922a2f6a774b6dac19f70cb5abd86bb0, when
ocfs2_attch_dentry_lock fails, we call an extra iput and reset
dentry->d_fsdata to NULL. This resolve a bug, but it isn't
completed and the dentry is still there. When we want to use
it again, ocfs2_dentry_revalidate doesn't catch it and return
true. That make future ocfs2_dentry_lock panic out.
One bug is http://oss.oracle.com/bugzilla/show_bug.cgi?id=1162.

The resolution is to add a check for dentry->d_fsdata in
revalidate process and return false if dentry->d_fsdata is NULL,
so that a new ocfs2_lookup will be called again.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

diff --git a/fs/ocfs2/dcache.c b/fs/ocfs2/dcache.c
index 2f28b7de2c8d2cae30d052e54fc12fa7e91c740f..b4957c7d9fe2262a203a3efb3573eda9ed3d2638 100644 (file)
--- a/fs/ocfs2/dcache.c
+++ b/fs/ocfs2/dcache.c
@@ -85,6 +85,17 @@ static int ocfs2_dentry_revalidate(struct dentry *dentry,
                goto bail;
        }
 
+       /*
+        * If the last lookup failed to create dentry lock, let us
+        * redo it.
+        */
+       if (!dentry->d_fsdata) {
+               mlog(0, "Inode %llu doesn't have dentry lock, "
+                    "returning false\n",
+                    (unsigned long long)OCFS2_I(inode)->ip_blkno);
+               goto bail;
+       }
+
        ret = 1;
 
 bail: