From: Valerie Aurora <vaurora@xxxxxxxxxx>
union_add_dir() fills out the union stack for the topmost dentry with
the path of the directory in this layer of the union.
---
fs/union.c | 27 +++++++++++++++++++++++++++
fs/union.h | 2 ++
2 files changed, 29 insertions(+), 0 deletions(-)
diff --git a/fs/union.c b/fs/union.c
index 77d6a74..ee4613b 100644
--- a/fs/union.c
+++ b/fs/union.c
@@ -60,3 +60,30 @@ void d_free_unions(struct dentry *topmost)
kfree(topmost->d_union_stack);
topmost->d_union_stack = NULL;
}
+
+/**
+ * union_add_dir - Add another layer to a unioned directory
+ * @topmost: topmost directory
+ * @lower: directory in the current layer
+ * @layer: index of layer to add this at
+ *
+ * @layer counts starting at 0 for the dir below the topmost dir. Must take a
+ * reference to @lower (call path_get()) before calling this function.
+ */
+int union_add_dir(struct path *topmost, struct path *lower,
+ unsigned int layer)
+{
+ struct dentry *dentry = topmost->dentry;
+ struct path *path;
+
+ BUG_ON(layer >= dentry->d_sb->s_union_count);
+
+ if (!dentry->d_union_stack)
+ dentry->d_union_stack = union_alloc(topmost);
+ if (!dentry->d_union_stack)
+ return -ENOMEM;
+
+ path = union_find_dir(dentry, layer);
+ *path = *lower;
+ return 0;
+}
diff --git a/fs/union.h b/fs/union.h
index 5b79131..51a851b 100644
--- a/fs/union.h
+++ b/fs/union.h
@@ -52,6 +52,7 @@ struct union_stack {
#define IS_DIR_UNIONED(dentry) ((dentry)->d_union_stack)
extern void d_free_unions(struct dentry *);
+extern int union_add_dir(struct path *, struct path *, unsigned int);
static inline
struct path *union_find_dir(struct dentry *dentry, unsigned int layer)
@@ -65,6 +66,7 @@ struct path *union_find_dir(struct dentry *dentry, unsigned int layer)
#define IS_DIR_UNIONED(x) (0)
#define d_free_unions(x) do { } while (0)
+#define union_add_dir(x, y, z) ({ BUG(); (0); })
#define union_find_dir(x, y) ({ BUG(); (NULL); })
#endif /* CONFIG_UNION_MOUNT */
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
