[PATCH V3] resize2fs: clear uninit BG if allocating from new group

[Eric Sandeen <sandeen@redhat.com>]

If resize2fs_get_alloc_block() allocates from a BLOCK_UNINIT
group, nothing clears the UNINIT flag, so it is skipped when we
go to write out modified bitmaps.  This leads to post-resize2fs
e2fsck errors; used blocks in UNINIT groups, not marked in the
block bitmap.  This was seen on r_ext4_small_bg.

This patch uses clear_block_uninit() to clear the flag,
and my problem goes away.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

V2: don't cut and paste, sorry! 
V3: ext2fs_* namespace for the exported function, thanks Darrick

Thanks,
-Eric

diff --git a/lib/ext2fs/alloc.c b/lib/ext2fs/alloc.c
index 86e7f99..ce59e85 100644
--- a/lib/ext2fs/alloc.c
+++ b/lib/ext2fs/alloc.c
@@ -39,7 +39,7 @@
 /*
  * Clear the uninit block bitmap flag if necessary
  */
-static void clear_block_uninit(ext2_filsys fs, dgrp_t group)
+void ext2fs_clear_block_uninit(ext2_filsys fs, dgrp_t group)
 {
 	if (!ext2fs_has_group_desc_csum(fs) ||
 	    !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
@@ -183,7 +183,7 @@ allocated:
 	if (retval)
 		return retval;
 
-	clear_block_uninit(fs, ext2fs_group_of_blk2(fs, b));
+	ext2fs_clear_block_uninit(fs, ext2fs_group_of_blk2(fs, b));
 	*ret = b;
 	return 0;
 }
@@ -455,7 +455,7 @@ errcode_t ext2fs_new_range(ext2_filsys fs, int flags, blk64_t goal,
 allocated:
 			for (b = start; b < end;
 			     b += fs->super->s_blocks_per_group)
-				clear_block_uninit(fs,
+				ext2fs_clear_block_uninit(fs,
 						ext2fs_group_of_blk2(fs, b));
 			return 0;
 		}
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 86d860f..d5e9684 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -647,6 +647,7 @@ static inline int ext2fs_needs_large_file_feature(unsigned long long file_size)
 }
 
 /* alloc.c */
+extern void ext2fs_clear_block_uninit(ext2_filsys fs, dgrp_t group);
 extern errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir, int mode,
 				  ext2fs_inode_bitmap map, ext2_ino_t *ret);
 extern errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index 07c6a0c..42435b2 100644
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c
@@ -1620,6 +1620,7 @@ static errcode_t resize2fs_get_alloc_block(ext2_filsys fs,
 {
 	ext2_resize_t rfs = (ext2_resize_t) fs->priv_data;
 	blk64_t blk;
+	int group;
 
 	blk = get_new_block(rfs);
 	if (!blk)
@@ -1632,6 +1633,12 @@ static errcode_t resize2fs_get_alloc_block(ext2_filsys fs,
 
 	ext2fs_mark_block_bitmap2(rfs->old_fs->block_map, blk);
 	ext2fs_mark_block_bitmap2(rfs->new_fs->block_map, blk);
+
+	group = ext2fs_group_of_blk2(rfs->old_fs, blk);
+	ext2fs_clear_block_uninit(rfs->old_fs, group);
+	group = ext2fs_group_of_blk2(rfs->new_fs, blk);
+	ext2fs_clear_block_uninit(rfs->new_fs, group);
+
 	*ret = (blk64_t) blk;
 	return 0;
 }