[RFC 2/8] overlayfs: Switch to generic xattr handlers

[Andreas Gruenbacher <agruenba@redhat.com>]

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/overlayfs/dir.c       |  6 +++---
 fs/overlayfs/inode.c     | 52 ++++++++++++++++++++++++++++++++++++++----------
 fs/overlayfs/overlayfs.h |  6 +-----
 fs/overlayfs/super.c     |  1 +
 4 files changed, 46 insertions(+), 19 deletions(-)

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index b3fc0a3..16ba0f8 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -967,8 +967,8 @@ const struct inode_operations ovl_dir_inode_operations = {
 	.mknod		= ovl_mknod,
 	.permission	= ovl_permission,
 	.getattr	= ovl_dir_getattr,
-	.setxattr	= ovl_setxattr,
-	.getxattr	= ovl_getxattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= ovl_listxattr,
-	.removexattr	= ovl_removexattr,
+	.removexattr	= generic_removexattr,
 };
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index c7b31a0..d08c926 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -210,8 +210,8 @@ static bool ovl_is_private_xattr(const char *name)
 	return strncmp(name, OVL_XATTR_PRE_NAME, OVL_XATTR_PRE_LEN) == 0;
 }
 
-int ovl_setxattr(struct dentry *dentry, const char *name,
-		 const void *value, size_t size, int flags)
+static int ovl_setxattr(struct dentry *dentry, const char *name,
+			const void *value, size_t size, int flags)
 {
 	int err;
 	struct dentry *upperdentry;
@@ -246,8 +246,8 @@ static bool ovl_need_xattr_filter(struct dentry *dentry,
 		return false;
 }
 
-ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
-		     const char *name, void *value, size_t size)
+static ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
+			    const char *name, void *value, size_t size)
 {
 	struct path realpath;
 	enum ovl_path_type type = ovl_path_real(dentry, &realpath);
@@ -290,7 +290,7 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
 	return res;
 }
 
-int ovl_removexattr(struct dentry *dentry, const char *name)
+static int ovl_removexattr(struct dentry *dentry, const char *name)
 {
 	int err;
 	struct path realpath;
@@ -374,10 +374,10 @@ static const struct inode_operations ovl_file_inode_operations = {
 	.setattr	= ovl_setattr,
 	.permission	= ovl_permission,
 	.getattr	= ovl_getattr,
-	.setxattr	= ovl_setxattr,
-	.getxattr	= ovl_getxattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= ovl_listxattr,
-	.removexattr	= ovl_removexattr,
+	.removexattr	= generic_removexattr,
 };
 
 static const struct inode_operations ovl_symlink_inode_operations = {
@@ -385,10 +385,10 @@ static const struct inode_operations ovl_symlink_inode_operations = {
 	.get_link	= ovl_get_link,
 	.readlink	= ovl_readlink,
 	.getattr	= ovl_getattr,
-	.setxattr	= ovl_setxattr,
-	.getxattr	= ovl_getxattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= ovl_listxattr,
-	.removexattr	= ovl_removexattr,
+	.removexattr	= generic_removexattr,
 };
 
 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
@@ -433,3 +433,33 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
 
 	return inode;
 }
+
+static int ovl_xattr_get(const struct xattr_handler *handler,
+			 struct dentry *dentry, struct inode *inode,
+			 const char *name, void *buffer, size_t size)
+{
+	return ovl_getxattr(dentry, inode, name, buffer, size);
+}
+
+static int ovl_xattr_set(const struct xattr_handler *handler,
+                             struct dentry *dentry, const char *name,
+                             const void *value, size_t size, int flags)
+{
+	if (value)
+		return ovl_setxattr(dentry, name, value, size, flags);
+	else {
+		BUG_ON(flags != XATTR_REPLACE);
+		return ovl_removexattr(dentry, name);
+	}
+}
+
+const struct xattr_handler ovl_xattr_handler = {
+	.prefix = "",  /* match anything */
+	.get = ovl_xattr_get,
+	.set = ovl_xattr_set,
+};
+
+const struct xattr_handler *ovl_xattr_handlers[] = {
+	&ovl_xattr_handler,
+	NULL
+};
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 99ec4b0..b7528e5 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -171,12 +171,7 @@ int ovl_check_d_type_supported(struct path *realpath);
 /* inode.c */
 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
 int ovl_permission(struct inode *inode, int mask);
-int ovl_setxattr(struct dentry *dentry, const char *name,
-		 const void *value, size_t size, int flags);
-ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
-		     const char *name, void *value, size_t size);
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
-int ovl_removexattr(struct dentry *dentry, const char *name);
 struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags);
 
 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
@@ -186,6 +181,7 @@ static inline void ovl_copyattr(struct inode *from, struct inode *to)
 	to->i_uid = from->i_uid;
 	to->i_gid = from->i_gid;
 }
+extern const struct xattr_handler *ovl_xattr_handlers[];
 
 /* dir.c */
 extern const struct inode_operations ovl_dir_inode_operations;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 14cab38..46073fc 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1106,6 +1106,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 
 	sb->s_magic = OVERLAYFS_SUPER_MAGIC;
 	sb->s_op = &ovl_super_operations;
+	sb->s_xattr = ovl_xattr_handlers;
 	sb->s_root = root_dentry;
 	sb->s_fs_info = ufs;
 
-- 
2.5.5