fs: add generic xattr_acl handlers

With the ->set_acl inode operation we can implement the Posix ACL
xattr handlers in generic code instead of duplicating them all
over the tree.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 30524de49a6bc47c7c47e6f1f58ccddb1432d6b9..e699b076cdd8a51974777c3ae3548f2c6e3ce1df 100644 (file)
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -17,6 +17,7 @@
 #include <linux/sched.h>
 #include <linux/posix_acl.h>
 #include <linux/posix_acl_xattr.h>
+#include <linux/xattr.h>
 #include <linux/export.h>
 #include <linux/user_namespace.h>
 
@@ -611,3 +612,104 @@ posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
        return real_size;
 }
 EXPORT_SYMBOL (posix_acl_to_xattr);
+
+static int
+posix_acl_xattr_get(struct dentry *dentry, const char *name,
+               void *value, size_t size, int type)
+{
+       struct posix_acl *acl;
+       int error;
+
+       if (!IS_POSIXACL(dentry->d_inode))
+               return -EOPNOTSUPP;
+       if (S_ISLNK(dentry->d_inode->i_mode))
+               return -EOPNOTSUPP;
+
+       acl = get_acl(dentry->d_inode, type);
+       if (IS_ERR(acl))
+               return PTR_ERR(acl);
+       if (acl == NULL)
+               return -ENODATA;
+
+       error = posix_acl_to_xattr(&init_user_ns, acl, value, size);
+       posix_acl_release(acl);
+
+       return error;
+}
+
+static int
+posix_acl_xattr_set(struct dentry *dentry, const char *name,
+               const void *value, size_t size, int flags, int type)
+{
+       struct inode *inode = dentry->d_inode;
+       struct posix_acl *acl = NULL;
+       int ret;
+
+       if (!IS_POSIXACL(inode))
+               return -EOPNOTSUPP;
+       if (!inode->i_op->set_acl)
+               return -EOPNOTSUPP;
+
+       if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
+               return value ? -EACCES : 0;
+       if (!inode_owner_or_capable(inode))
+               return -EPERM;
+
+       if (value) {
+               acl = posix_acl_from_xattr(&init_user_ns, value, size);
+               if (IS_ERR(acl))
+                       return PTR_ERR(acl);
+
+               if (acl) {
+                       ret = posix_acl_valid(acl);
+                       if (ret)
+                               goto out;
+               }
+       }
+
+       ret = inode->i_op->set_acl(inode, acl, type);
+out:
+       posix_acl_release(acl);
+       return ret;
+}
+
+static size_t
+posix_acl_xattr_list(struct dentry *dentry, char *list, size_t list_size,
+               const char *name, size_t name_len, int type)
+{
+       const char *xname;
+       size_t size;
+
+       if (!IS_POSIXACL(dentry->d_inode))
+               return -EOPNOTSUPP;
+       if (S_ISLNK(dentry->d_inode->i_mode))
+               return -EOPNOTSUPP;
+
+       if (type == ACL_TYPE_ACCESS)
+               xname = POSIX_ACL_XATTR_ACCESS;
+       else
+               xname = POSIX_ACL_XATTR_DEFAULT;
+
+       size = strlen(xname) + 1;
+       if (list && size <= list_size)
+               memcpy(list, xname, size);
+       return size;
+}
+
+const struct xattr_handler posix_acl_access_xattr_handler = {
+       .prefix = POSIX_ACL_XATTR_ACCESS,
+       .flags = ACL_TYPE_ACCESS,
+       .list = posix_acl_xattr_list,
+       .get = posix_acl_xattr_get,
+       .set = posix_acl_xattr_set,
+};
+EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler);
+
+const struct xattr_handler posix_acl_default_xattr_handler = {
+       .prefix = POSIX_ACL_XATTR_DEFAULT,
+       .flags = ACL_TYPE_DEFAULT,
+       .list = posix_acl_xattr_list,
+       .get = posix_acl_xattr_get,
+       .set = posix_acl_xattr_set,
+};
+EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler);

diff --git a/include/linux/posix_acl_xattr.h b/include/linux/posix_acl_xattr.h
index ad93ad0f1db0b0afe072d587a6fd1507f2e35d84..6f14ee2958220b03afcb8c41a8fc2cdcad9ea940 100644 (file)
--- a/include/linux/posix_acl_xattr.h
+++ b/include/linux/posix_acl_xattr.h
@@ -69,4 +69,7 @@ struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns,
 int posix_acl_to_xattr(struct user_namespace *user_ns,
                       const struct posix_acl *acl, void *buffer, size_t size);
 
+extern const struct xattr_handler posix_acl_access_xattr_handler;
+extern const struct xattr_handler posix_acl_default_xattr_handler;
+
 #endif /* _POSIX_ACL_XATTR_H */