ovl: factor out ovl_free_entry() and ovl_stack_*() helpers

In preparation for moving lowerstack into ovl_inode.

Note that in ovl_lookup() the temp stack dentry refs are now cloned
into the final ovl_lowerstack instead of being transferred, so cleanup
always needs to call ovl_stack_free(stack).

Reviewed-by: Alexander Larsson <alexl@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index a146c7ab8d8e..4ff58f92100d 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -83,6 +83,34 @@ bool ovl_verify_lower(struct super_block *sb)
 	return ofs->config.nfs_export && ofs->config.index;
 }
 
+struct ovl_path *ovl_stack_alloc(unsigned int n)
+{
+	return kcalloc(n, sizeof(struct ovl_path), GFP_KERNEL);
+}
+
+void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n)
+{
+	unsigned int i;
+
+	memcpy(dst, src, sizeof(struct ovl_path) * n);
+	for (i = 0; i < n; i++)
+		dget(src[i].dentry);
+}
+
+void ovl_stack_put(struct ovl_path *stack, unsigned int n)
+{
+	unsigned int i;
+
+	for (i = 0; stack && i < n; i++)
+		dput(stack[i].dentry);
+}
+
+void ovl_stack_free(struct ovl_path *stack, unsigned int n)
+{
+	ovl_stack_put(stack, n);
+	kfree(stack);
+}
+
 struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
 {
 	size_t size = offsetof(struct ovl_entry, __lowerstack[numlower]);
@@ -94,6 +122,12 @@ struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
 	return oe;
 }
 
+void ovl_free_entry(struct ovl_entry *oe)
+{
+	ovl_stack_put(ovl_lowerstack(oe), ovl_numlower(oe));
+	kfree(oe);
+}
+
 #define OVL_D_REVALIDATE (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE)
 
 bool ovl_dentry_remote(struct dentry *dentry)