[PATCH 10/13] erofs-utils: lib: add erofs_rebuild_dump_tree() helper

[Jingbo Xu <jefflexu@linux.alibaba.com>]

Enhance tarerofs_dump_tree() so that it could optionally skip whiteout
files when it's supposed to output image in merged view.  Rename it to
erofs_rebuild_dump_tree().

Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
---
 include/erofs/inode.h    |  2 +-
 include/erofs/internal.h |  2 ++
 lib/inode.c              | 23 ++++++++++++++++++++---
 lib/tar.c                |  2 --
 mkfs/main.c              |  2 +-
 5 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/include/erofs/inode.h b/include/erofs/inode.h
index 1c602a8..f273e9e 100644
--- a/include/erofs/inode.h
+++ b/include/erofs/inode.h
@@ -32,7 +32,7 @@ unsigned int erofs_iput(struct erofs_inode *inode);
 erofs_nid_t erofs_lookupnid(struct erofs_inode *inode);
 struct erofs_dentry *erofs_d_alloc(struct erofs_inode *parent,
 				   const char *name);
-int tarerofs_dump_tree(struct erofs_inode *dir);
+int erofs_rebuild_dump_tree(struct erofs_inode *dir, bool merged_view);
 int erofs_init_empty_dir(struct erofs_inode *dir);
 struct erofs_inode *erofs_new_inode(void);
 struct erofs_inode *erofs_mkfs_build_tree_from_path(const char *path);
diff --git a/include/erofs/internal.h b/include/erofs/internal.h
index 3631cc1..179ecb3 100644
--- a/include/erofs/internal.h
+++ b/include/erofs/internal.h
@@ -416,6 +416,8 @@ static inline u32 erofs_crc32c(u32 crc, const u8 *in, size_t len)
 	return crc;
 }
 
+#define EROFS_WHITEOUT_DEV	0
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/inode.c b/lib/inode.c
index b967aab..7f59a58 100644
--- a/lib/inode.c
+++ b/lib/inode.c
@@ -1323,9 +1323,14 @@ struct erofs_inode *erofs_mkfs_build_special_from_fd(int fd, const char *name)
 	return inode;
 }
 
-int tarerofs_dump_tree(struct erofs_inode *dir)
+static bool erofs_inode_is_whiteout(struct erofs_inode *inode)
 {
-	struct erofs_dentry *d;
+	return S_ISCHR(inode->i_mode) && inode->u.i_rdev == EROFS_WHITEOUT_DEV;
+}
+
+int erofs_rebuild_dump_tree(struct erofs_inode *dir, bool merged_view)
+{
+	struct erofs_dentry *d, *n;
 	unsigned int nr_subdirs;
 	int ret;
 
@@ -1368,6 +1373,18 @@ int tarerofs_dump_tree(struct erofs_inode *dir)
 		return 0;
 	}
 
+	if (merged_view) {
+		list_for_each_entry_safe(d, n, &dir->i_subdirs, d_child) {
+			if (erofs_inode_is_whiteout(d->inode)) {
+				erofs_dbg("skip whiteout %s", d->inode->i_srcpath);
+				erofs_d_invalidate(d);
+				list_del(&d->d_child);
+				free(d);
+				continue;
+			}
+		}
+	}
+
 	nr_subdirs = 0;
 	list_for_each_entry(d, &dir->i_subdirs, d_child)
 		++nr_subdirs;
@@ -1391,7 +1408,7 @@ int tarerofs_dump_tree(struct erofs_inode *dir)
 			continue;
 
 		inode = erofs_igrab(d->inode);
-		ret = tarerofs_dump_tree(inode);
+		ret = erofs_rebuild_dump_tree(inode, merged_view);
 		dir->i_nlink += (erofs_mode_to_ftype(inode->i_mode) == EROFS_FT_DIR);
 		erofs_iput(inode);
 		if (ret)
diff --git a/lib/tar.c b/lib/tar.c
index d7a58d2..3205f06 100644
--- a/lib/tar.c
+++ b/lib/tar.c
@@ -19,8 +19,6 @@
 #include "erofs/xattr.h"
 #include "erofs/blobchunk.h"
 
-#define EROFS_WHITEOUT_DEV	0
-
 static char erofs_libbuf[16384];
 
 struct tar_header {
diff --git a/mkfs/main.c b/mkfs/main.c
index c03a7a8..269ccf4 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -946,7 +946,7 @@ int main(int argc, char **argv)
 		if (err < 0)
 			goto exit;
 
-		err = tarerofs_dump_tree(root_inode);
+		err = erofs_rebuild_dump_tree(root_inode, false);
 		if (err < 0)
 			goto exit;
 	}
-- 
2.19.1.6.gb485710b