reisze2fs: sanity check free block group counts when calculating minimum size

[thirdparty/e2fsprogs.git] / resize / resize2fs.c

diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index 73174be0322db3df07abf31477a151b5b4acbe15..b9783e8ccd38be92a6f478d23f791b1bd038c391 100644 (file)
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c
@@ -3002,8 +3002,17 @@ blk64_t calculate_minimum_resize_size(ext2_filsys fs, int flags)
        /* calculate how many blocks are needed for data */
        data_needed = ext2fs_blocks_count(fs->super);
        for (grp = 0; grp < fs->group_desc_count; grp++) {
-               data_needed -= calc_group_overhead(fs, grp, old_desc_blocks);
-               data_needed -= ext2fs_bg_free_blocks_count(fs, grp);
+               __u32 n = ext2fs_bg_free_blocks_count(fs, grp);
+
+               if (n > EXT2_BLOCKS_PER_GROUP(fs->super))
+                       n = EXT2_BLOCKS_PER_GROUP(fs->super);
+               n += calc_group_overhead(fs, grp, old_desc_blocks);
+               if (data_needed < n) {
+                       if (flags & RESIZE_DEBUG_MIN_CALC)
+                               printf("file system appears inconsistent?!?\n");
+                       return ext2fs_blocks_count(fs->super);
+               }
+               data_needed -= n;
        }
 #ifdef RESIZE2FS_DEBUG
        if (flags & RESIZE_DEBUG_MIN_CALC)