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 55fc29bed8dd ("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().
Unified · Split
| @@ -3044,6 +3044,8 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device · 3043 unmodified lines | |||
| 3044 | goto fail_alloc; | 3044 | goto fail_alloc; |
| 3045 | } | 3045 | } |
| 3046 | 3046 | ||
| 3047 | fs_info->csum_size = btrfs_super_csum_size(disk_super); | ||
| 3048 | |||
| 3047 | ret = btrfs_init_csum_hash(fs_info, csum_type); | 3049 | ret = btrfs_init_csum_hash(fs_info, csum_type); |
| 3048 | if (ret) { | 3050 | if (ret) { |
| 3049 | err = ret; | 3051 | err = ret; |
| @@ -3161,7 +3163,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device · 111 unmodified lines | |||
| 3161 | fs_info->nodesize = nodesize; | 3163 | fs_info->nodesize = nodesize; |
| 3162 | fs_info->sectorsize = sectorsize; | 3164 | fs_info->sectorsize = sectorsize; |
| 3163 | fs_info->sectorsize_bits = ilog2(sectorsize); | 3165 | fs_info->sectorsize_bits = ilog2(sectorsize); |
| 3164 | fs_info->csum_size = btrfs_super_csum_size(disk_super); | ||
| 3165 | fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size; | 3166 | fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size; |
| 3166 | fs_info->stripesize = stripesize; | 3167 | fs_info->stripesize = stripesize; |
| 3167 | 3168 | ||