GIT: unionfs2-2.6.27.y: Post-copyup helper functions

[Erez Zadok]

commit 4304cbc51af99cd192a6323bd8b08d97cd51e90b
Author: Erez Zadok <ezk at bigvaio.(none)>
Date:   Fri May 18 01:31:14 2007 -0400

    Post-copyup helper functions
    
    Two functions which are very useful to execute common actions needed after a
    copy-up had taken place.

diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
index bed2419..2cf1878 100644
--- a/fs/unionfs/copyup.c
+++ b/fs/unionfs/copyup.c
@@ -798,3 +798,51 @@ out:
 	kfree(path);
 	return hidden_dentry;
 }
+
+/* set lower mnt of dentry+parents to the first parent node that has an mnt */
+void unionfs_inherit_mnt(struct dentry *dentry)
+{
+	struct dentry *parent, *hasone;
+	int bindex = dbstart(dentry);
+
+	if (unionfs_lower_mnt_idx(dentry, bindex))
+		return;
+	hasone = dentry->d_parent;
+	/* this loop should stop at root dentry */
+	while (!unionfs_lower_mnt_idx(hasone, bindex)) {
+		hasone = hasone->d_parent;
+	}
+	parent = dentry;
+	while (!unionfs_lower_mnt_idx(parent, bindex)) {
+		unionfs_set_lower_mnt_idx(parent, bindex,
+					  unionfs_mntget(hasone, bindex));
+		parent = parent->d_parent;
+	}
+}
+
+/*
+ * Regular files should have only one lower object(s).  On copyup, we may
+ * have leftover objects from previous branches.  So purge all such extra
+ * objects and keep only the most recent, leftmost, copied-up one.
+ */
+void unionfs_purge_extras(struct dentry *dentry)
+{
+	int bindex;
+
+	BUG_ON(S_ISDIR(dentry->d_inode->i_mode));
+	for (bindex=dbstart(dentry)+1; bindex<=dbend(dentry); bindex++) {
+		if (unionfs_lower_mnt_idx(dentry, bindex)) {
+			unionfs_mntput(dentry, bindex);
+			unionfs_set_lower_mnt_idx(dentry, bindex, NULL);
+		}
+		if (unionfs_lower_dentry_idx(dentry, bindex)) {
+			dput(unionfs_lower_dentry_idx(dentry, bindex));
+			unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
+			iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
+			unionfs_set_lower_inode_idx(dentry->d_inode, bindex, NULL);
+		}
+	}
+	bindex = dbstart(dentry);
+	set_dbend(dentry, bindex);
+	ibend(dentry->d_inode) = ibstart(dentry->d_inode) = bindex;
+}
diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
index f645d53..7a4f627 100644
--- a/fs/unionfs/union.h
+++ b/fs/unionfs/union.h
@@ -268,6 +268,9 @@ extern int copyup_named_file(struct inode *dir, struct file *file,
 extern int copyup_dentry(struct inode *dir, struct dentry *dentry, int bstart,
 			 int new_bindex, struct file **copyup_file,
 			 loff_t len);
+/* helper functions for post-copyup cleanup */
+extern void unionfs_inherit_mnt(struct dentry *dentry);
+extern void unionfs_purge_extras(struct dentry *dentry);
 
 extern int remove_whiteouts(struct dentry *dentry,
 			    struct dentry *hidden_dentry, int bindex);