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authorMiklos Szeredi <mszeredi@suse.cz>2014-12-13 02:59:43 +0300
committerMiklos Szeredi <mszeredi@suse.cz>2014-12-13 02:59:43 +0300
commit5ef88da56a77bfb3b9631f5e5775f3bff86b6219 (patch)
treed09b7c8612f7652576ae3b75b80f7aaec303143e /fs/overlayfs
parentdd662667e6d3e55b42798a6e6e7f37dddc639460 (diff)
downloadlinux-5ef88da56a77bfb3b9631f5e5775f3bff86b6219.tar.xz
ovl: helper to iterate layers
Add helper to iterate through all the layers, starting from the upper layer (if exists) and continuing down through the lower layers. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/overlayfs.h1
-rw-r--r--fs/overlayfs/super.c21
2 files changed, 22 insertions, 0 deletions
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index d39eaa8f5e47..d176b679f526 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -135,6 +135,7 @@ void ovl_dentry_version_inc(struct dentry *dentry);
void ovl_path_upper(struct dentry *dentry, struct path *path);
void ovl_path_lower(struct dentry *dentry, struct path *path);
enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
+int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
struct dentry *ovl_dentry_upper(struct dentry *dentry);
struct dentry *ovl_dentry_lower(struct dentry *dentry);
struct dentry *ovl_dentry_real(struct dentry *dentry);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 460d866b97a2..07e4c576e93e 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -305,6 +305,27 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir,
return dentry;
}
+/*
+ * Returns next layer in stack starting from top.
+ * Returns -1 if this is the last layer.
+ */
+int ovl_path_next(int idx, struct dentry *dentry, struct path *path)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ BUG_ON(idx < 0);
+ if (idx == 0) {
+ ovl_path_upper(dentry, path);
+ if (path->dentry)
+ return oe->numlower ? 1 : -1;
+ idx++;
+ }
+ BUG_ON(idx > oe->numlower);
+ *path = oe->lowerstack[idx - 1];
+
+ return (idx < oe->numlower) ? idx + 1 : -1;
+}
+
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{