AOSP: e2fsdroid: Properly free the dedup block map.
When BaseFS specifies the same block for two files, it gets added to a
separate "dedup" bitmap, and removed from the free block bitmap. If the
new build does not use every block in this bitmap, there will be an
inconsistency: the block bitmap marks blocks as in-use when they are
actually free. Although this doesn't matter for AOSP's read-only file
systems, it does cause e2fsck to complain, which breaks the build.
Fix the inconsistency by properly freeing all unused blocks within the
dedup block set.
Bug: 139201772
Test: build AOSP using BaseFS
Change-Id: I6b6511eb713a56fec932f1d5668f1766d64d9479
From AOSP commit: 346bee6f8b97aefe7714688f738606c116099fbc
diff --git a/contrib/android/basefs_allocator.c b/contrib/android/basefs_allocator.c
index 658a751..325aed8 100644
--- a/contrib/android/basefs_allocator.c
+++ b/contrib/android/basefs_allocator.c
@@ -39,6 +39,28 @@
}
}
+/*
+ * Free any blocks in the bitmap that were reserved but never used. This is
+ * needed to free dedup_block_map and ensure the free block bitmap is
+ * internally consistent.
+ */
+static void fs_free_blocks_bitmap(ext2_filsys fs, ext2fs_block_bitmap bitmap)
+{
+ blk64_t block = 0;
+ blk64_t start = fs->super->s_first_data_block;
+ blk64_t end = ext2fs_blocks_count(fs->super) - 1;
+ errcode_t retval;
+
+ for (;;) {
+ retval = ext2fs_find_first_set_block_bitmap2(bitmap, start, end,
+ &block);
+ if (retval)
+ break;
+ ext2fs_unmark_block_bitmap2(fs->block_map, block);
+ start = block + 1;
+ }
+}
+
static void basefs_allocator_free(ext2_filsys fs,
struct base_fs_allocator *allocator)
{
@@ -53,6 +75,7 @@
}
ext2fs_hashmap_free(entries);
}
+ fs_free_blocks_bitmap(fs, allocator->dedup_block_map);
ext2fs_free_block_bitmap(allocator->exclusive_block_map);
ext2fs_free_block_bitmap(allocator->dedup_block_map);
free(allocator);
