[PATCH] ocfs2: comment missing-cluster-lock warning

["J. Bruce Fields" <bfields@fieldses.org>]

From: "J. Bruce Fields" <bfields@redhat.com>

Add some explanation of the DCACHE_DISCONNECTED use here.  And hide away
the boring warning code in a helper function.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/ocfs2/dcache.c |   40 +++++++++++++++++++++++++---------------
 1 file changed, 25 insertions(+), 15 deletions(-)

By the way, something like this might save me a little time next time I
run across this and forget this conversation.  But, no big deal if you
think it's overkill.  Untested except by a make fs/ocfs2/dcache.o.

diff --git a/fs/ocfs2/dcache.c b/fs/ocfs2/dcache.c
index 8db4b58..27677ab 100644
--- a/fs/ocfs2/dcache.c
+++ b/fs/ocfs2/dcache.c
@@ -446,26 +446,36 @@ void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
 		ocfs2_drop_dentry_lock(osb, dl);
 }
 
+static void ocfs2_warn_if_missing_lock(struct dentry *dentry, struct inode *inode)
+{
+	unsigned long long ino = 0ULL;
+
+	/* It's OK not to have the dentry lock on an unhashed dentry: */
+	if (d_unhashed(dentry))
+		return;
+	/*
+	 * It's also fine if we're disconnected.  (Note: a dentry may be
+	 * marked DCACHE_DISCONNECTED for a brief time after it's been
+	 * fully connected, so we may fail to warn in some cases we
+	 * should.  We prefer that to warning when we shouldn't.)
+	 */
+	if (dentry->d_flags & DCACHE_DISCONNECTED)
+		return;
+
+	if (inode)
+		ino = (unsigned long long)OCFS2_I(inode)->ip_blkno;
+	mlog(ML_ERROR, "Dentry is missing cluster lock. "
+	     "inode: %llu, d_flags: 0x%x, d_name: %.*s\n",
+	     ino, dentry->d_flags, dentry->d_name.len,
+	     dentry->d_name.name);
+}
+
 static void ocfs2_dentry_iput(struct dentry *dentry, struct inode *inode)
 {
 	struct ocfs2_dentry_lock *dl = dentry->d_fsdata;
 
 	if (!dl) {
-		/*
-		 * No dentry lock is ok if we're disconnected or
-		 * unhashed.
-		 */
-		if (!(dentry->d_flags & DCACHE_DISCONNECTED) &&
-		    !d_unhashed(dentry)) {
-			unsigned long long ino = 0ULL;
-			if (inode)
-				ino = (unsigned long long)OCFS2_I(inode)->ip_blkno;
-			mlog(ML_ERROR, "Dentry is missing cluster lock. "
-			     "inode: %llu, d_flags: 0x%x, d_name: %.*s\n",
-			     ino, dentry->d_flags, dentry->d_name.len,
-			     dentry->d_name.name);
-		}
-
+		ocfs2_warn_if_missing_lock(dentry, inode);
 		goto out;
 	}
 
-- 
1.7.9.5