[PATCH v6 1/2] erofs-utils: lib: introduce erofs_xattr_prefix_index()

[Hongzhen Luo]

Prepare for the feature of exporting extended attributes for
`fsck.erofs`, which requires obtaining the index based on the
name of the extended attribute.

Signed-off-by: Hongzhen Luo <hongzhen at linux.alibaba.com>
---
 include/erofs/xattr.h | 2 ++
 lib/xattr.c           | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/include/erofs/xattr.h b/include/erofs/xattr.h
index 7643611..7848fe7 100644
--- a/include/erofs/xattr.h
+++ b/include/erofs/xattr.h
@@ -61,6 +61,8 @@ void erofs_clear_opaque_xattr(struct erofs_inode *inode);
 int erofs_set_origin_xattr(struct erofs_inode *inode);
 int erofs_read_xattrs_from_disk(struct erofs_inode *inode);
 
+int erofs_xattr_prefix_index(const char *key);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/xattr.c b/lib/xattr.c
index 9f31f2d..1fed7c0 100644
--- a/lib/xattr.c
+++ b/lib/xattr.c
@@ -1681,3 +1681,10 @@ out:
 		erofs_xattr_prefixes_cleanup(sbi);
 	return ret;
 }
+
+int erofs_xattr_prefix_index(const char *key)
+{
+	unsigned int index, len;
+
+	return match_prefix(key, &index, &len) ? index : -EINVAL;
+}
-- 
2.43.5