btrfs: initialize fs_info::csum_size earlier in open_ctree

User reported that btrfs-progs misc-tests/028-superblock-recover fails: [TEST/misc] 028-superblock-recover unexpected success: mounted fs with corrupted superblock test failed for case 028-superblock-recover The test case expects that a broken image with bad superblock will be rejected to be mounted. However, the test image just passed csum check of superblock and was successfully mounted. Commit 55fc29b ("btrfs: use cached value of fs_info::csum_size everywhere") replaces all calls to btrfs_super_csum_size by fs_info::csum_size. The calls include the place where fs_info->csum_size is not initialized. So btrfs_check_super_csum() passes because memcmp() with len 0 always returns 0. Fix it by caching csum size in btrfs_fs_info::csum_size once we know the csum type in superblock is valid in open_ctree(). Link: kdave/btrfs-progs#250 Fixes: 55fc29b ("btrfs: use cached value of fs_info::csum_size everywhere") Signed-off-by: Su Yue <l@damenly.su> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
joeyli · Feb 12, 2021 · 83c68bb · 83c68bb
1 parent 9ad6d91
commit 83c68bb
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
@@ -3044,6 +3044,8 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 		goto fail_alloc;
 	}
 
+	fs_info->csum_size = btrfs_super_csum_size(disk_super);
+
 	ret = btrfs_init_csum_hash(fs_info, csum_type);
 	if (ret) {
 		err = ret;
@@ -3161,7 +3163,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	fs_info->nodesize = nodesize;
 	fs_info->sectorsize = sectorsize;
 	fs_info->sectorsize_bits = ilog2(sectorsize);
-	fs_info->csum_size = btrfs_super_csum_size(disk_super);
 	fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size;
 	fs_info->stripesize = stripesize;