resize2fs: during shrink, don't free in-use bg data clusters

When freeing a block group descriptor block, be careful not to free
metadata clusters belonging to other groups!

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index 27f508e..caff422 100644 (file)
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c
@@ -281,40 +281,61 @@ static void fix_uninit_block_bitmaps(ext2_filsys fs)
  * release them in the new filesystem data structure, and mark them as
  * reserved so the old inode table blocks don't get overwritten.
  */
-static void free_gdp_blocks(ext2_filsys fs,
-                           ext2fs_block_bitmap reserve_blocks,
-                           ext2_filsys old_fs,
-                           dgrp_t group)
+static errcode_t free_gdp_blocks(ext2_filsys fs,
+                                ext2fs_block_bitmap reserve_blocks,
+                                ext2_filsys old_fs,
+                                dgrp_t group)
 {
        blk64_t blk;
        int     j;
+       dgrp_t  i;
+       ext2fs_block_bitmap bg_map = NULL;
+       errcode_t retval = 0;
+       dgrp_t count = old_fs->group_desc_count - fs->group_desc_count;
+
+       /* If bigalloc, don't free metadata living in the same cluster */
+       if (EXT2FS_CLUSTER_RATIO(fs) > 1) {
+               retval = ext2fs_allocate_block_bitmap(fs, "bgdata", &bg_map);
+               if (retval)
+                       goto out;
 
-       blk = ext2fs_block_bitmap_loc(old_fs, group);
-       if (blk &&
-           (blk < ext2fs_blocks_count(fs->super))) {
-               ext2fs_block_alloc_stats2(fs, blk, -1);
-               ext2fs_mark_block_bitmap2(reserve_blocks, blk);
+               retval = mark_table_blocks(fs, bg_map);
+               if (retval)
+                       goto out;
        }
 
-       blk = ext2fs_inode_bitmap_loc(old_fs, group);
-       if (blk &&
-           (blk < ext2fs_blocks_count(fs->super))) {
-               ext2fs_block_alloc_stats2(fs, blk, -1);
-               ext2fs_mark_block_bitmap2(reserve_blocks, blk);
-       }
+       for (i = group; i < group + count; i++) {
+               blk = ext2fs_block_bitmap_loc(old_fs, i);
+               if (blk &&
+                   (blk < ext2fs_blocks_count(fs->super)) &&
+                   !(bg_map && ext2fs_test_block_bitmap2(bg_map, blk))) {
+                       ext2fs_block_alloc_stats2(fs, blk, -1);
+                       ext2fs_mark_block_bitmap2(reserve_blocks, blk);
+               }
 
-       blk = ext2fs_inode_table_loc(old_fs, group);
-       if (blk == 0 ||
-           (blk >= ext2fs_blocks_count(fs->super)))
-               return;
+               blk = ext2fs_inode_bitmap_loc(old_fs, i);
+               if (blk &&
+                   (blk < ext2fs_blocks_count(fs->super)) &&
+                   !(bg_map && ext2fs_test_block_bitmap2(bg_map, blk))) {
+                       ext2fs_block_alloc_stats2(fs, blk, -1);
+                       ext2fs_mark_block_bitmap2(reserve_blocks, blk);
+               }
 
-       for (j = 0;
-            j < fs->inode_blocks_per_group; j++, blk++) {
-               if (blk >= ext2fs_blocks_count(fs->super))
-                       break;
-               ext2fs_block_alloc_stats2(fs, blk, -1);
-               ext2fs_mark_block_bitmap2(reserve_blocks, blk);
+               blk = ext2fs_inode_table_loc(old_fs, i);
+               for (j = 0;
+                    j < fs->inode_blocks_per_group; j++, blk++) {
+                       if (blk >= ext2fs_blocks_count(fs->super) ||
+                           (bg_map && ext2fs_test_block_bitmap2(bg_map, blk)))
+                               continue;
+                       ext2fs_block_alloc_stats2(fs, blk, -1);
+                       ext2fs_mark_block_bitmap2(reserve_blocks, blk);
+               }
        }
+
+out:
+       if (bg_map)
+               ext2fs_free_block_bitmap(bg_map);
+       return retval;
 }
 
 /*
@@ -505,10 +526,8 @@ retry:
                 * Check the block groups that we are chopping off
                 * and free any blocks associated with their metadata
                 */
-               for (i = fs->group_desc_count;
-                    i < old_fs->group_desc_count; i++)
-                       free_gdp_blocks(fs, reserve_blocks, old_fs, i);
-               retval = 0;
+               retval = free_gdp_blocks(fs, reserve_blocks, old_fs,
+                                        fs->group_desc_count);
                goto errout;
        }