From 2dbf34e50562d08d5da4d3f373f3bc0b2fd46728 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 26 Jul 2014 00:45:28 -0400 Subject: [PATCH] libext2fs: fix rb_resize_bmap to handle the padding bits The bits between end and real_end are set as a safety measure for the kernel when it uses the bit scan instructions. We need to take this into account when shrinking or growing the block allocation bitmap, before we can safely use rbtree bitmaps in resize2fs. Signed-off-by: Theodore Ts'o --- lib/ext2fs/blkmap64_rb.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/lib/ext2fs/blkmap64_rb.c b/lib/ext2fs/blkmap64_rb.c index a1dde6d..fdbd330 100644 --- a/lib/ext2fs/blkmap64_rb.c +++ b/lib/ext2fs/blkmap64_rb.c @@ -299,21 +299,19 @@ static errcode_t rb_resize_bmap(ext2fs_generic_bitmap bmap, { struct ext2fs_rb_private *bp; - if (new_real_end >= bmap->real_end) { - bmap->end = new_end; - bmap->real_end = new_real_end; - return 0; - } - bp = (struct ext2fs_rb_private *) bmap->private; bp->rcursor = NULL; bp->wcursor = NULL; - /* truncate tree to new_real_end size */ - rb_truncate(new_real_end, &bp->root); + rb_truncate(((new_end < bmap->end) ? new_end : bmap->end) - bmap->start, + &bp->root); bmap->end = new_end; bmap->real_end = new_real_end; + + if (bmap->end < bmap->real_end) + rb_insert_extent(bmap->end + 1 - bmap->start, + bmap->real_end - bmap->end, bp); return 0; } -- 1.8.3.1