Re: [PATCH v6 0/2] exfat: get file size from DataLength

[Namjae Jeon <linkinjeon@kernel.org>]

2023-12-05 19:16 GMT+09:00, Yuezhang.Mo@sony.com <Yuezhang.Mo@sony.com>:
> From the exFAT specification, the file size should get from 'DataLength'
> of Stream Extension Directory Entry, not 'ValidDataLength'.
>
> Without this patch set, 'DataLength' is always same with 'ValidDataLength'
> and get file size from 'ValidDataLength'. If the file is created by other
> exFAT implementation and 'DataLength' is different from 'ValidDataLength',
> this exFAT implementation will not be compatible.
Have you ever run xfstests against v6 version ?
The page allocation failure problem in my test happen below.
What is your test result?

[ 3029.994963] run fstests generic/476 at 2023-12-12 09:39:35
[12514.707396] perf: interrupt took too long (2501 > 2500), lowering
kernel.perf_event_max_sample_rate to 79750
[13670.913452] fsstress: page allocation failure: order:0,
mode:0x40808(GFP_NOWAIT|__GFP_COMP|__GFP_MOVABLE),
nodemask=(null),cpuset=/,mems_allowed=0
[13670.913470] CPU: 0 PID: 297913 Comm: fsstress Tainted: G
OE      6.7.0-rc4 #1
[13670.913474] Hardware name: Dell Inc. Precision Tower 3620/0MWYPT,
BIOS 2.13.1 06/14/2019
[13670.913476] Call Trace:
[13670.913482]  <TASK>
[13670.913486]  dump_stack_lvl+0x48/0x70
[13670.913492]  dump_stack+0x10/0x20
[13670.913495]  warn_alloc+0x138/0x1b0
[13670.913501]  __alloc_pages+0x116b/0x1200
[13670.913504]  ? blk_mq_sched_try_merge+0x1be/0x1d0
[13670.913511]  ? policy_nodemask+0x10f/0x150
[13670.913516]  alloc_pages_mpol+0x91/0x220
[13670.913518]  ? filemap_get_entry+0xf3/0x180
[13670.913523]  alloc_pages+0x5e/0xd0
[13670.913525]  folio_alloc+0x18/0x50
[13670.913527]  filemap_alloc_folio+0xf5/0x100
[13670.913530]  __filemap_get_folio+0x112/0x2f0
[13670.913534]  __getblk_slow+0xba/0x250
[13670.913539]  __breadahead+0x8f/0xc0
[13670.913544]  exfat_get_dentry+0x155/0x1d0 [exfat]
[13670.913553]  ? _raw_spin_lock_irqsave+0x28/0x60
[13670.913557]  exfat_find_dir_entry+0x17b/0x740 [exfat]
[13670.913566]  ? __exfat_resolve_path+0x102/0x160 [exfat]
[13670.913574]  exfat_find+0xdd/0x340 [exfat]
[13670.913580]  ? update_load_avg+0x82/0x7d0
[13670.913584]  ? update_cfs_group+0xab/0xc0
[13670.913586]  ? psi_group_change+0x237/0x4e0
[13670.913590]  ? _raw_spin_unlock+0x19/0x40
[13670.913593]  ? raw_spin_rq_unlock+0x10/0x40
[13670.913598]  ? debug_smp_processor_id+0x17/0x20
[13670.913600]  ? mod_objcg_state+0xd0/0x350
[13670.913604]  ? memcg_slab_post_alloc_hook+0x195/0x230
[13670.913609]  ? kmem_cache_alloc_lru+0x1ca/0x3e0
[13670.913611]  ? __d_alloc+0x2e/0x200
[13670.913616]  exfat_lookup+0x55/0x200 [exfat]
[13670.913622]  ? preempt_count_add+0x54/0xc0
[13670.913626]  ? d_alloc_parallel+0x318/0x470
[13670.913628]  ? generic_permission+0x38/0x220
[13670.913632]  path_openat+0x588/0x1150
[13670.913637]  do_filp_open+0xb2/0x160
[13670.913643]  ? _raw_spin_unlock+0x19/0x40
[13670.913645]  ? alloc_fd+0xa9/0x190
[13670.913649]  do_sys_openat2+0x9b/0xd0
[13670.913653]  __x64_sys_creat+0x4b/0x70
[13670.913656]  do_syscall_64+0x5c/0xe0
[13670.913659]  ? __fput+0x16c/0x2f0
[13670.913661]  ? kmem_cache_free+0x190/0x3a0
[13670.913663]  ? percpu_counter_add_batch+0x35/0xb0
[13670.913666]  ? debug_smp_processor_id+0x17/0x20
[13670.913668]  ? fpregs_assert_state_consistent+0x2a/0x50
[13670.913672]  ? exit_to_user_mode_prepare+0x49/0x1a0
[13670.913675]  ? syscall_exit_to_user_mode+0x34/0x50
[13670.913677]  ? do_syscall_64+0x6b/0xe0
[13670.913679]  ? do_syscall_64+0x6b/0xe0
[13670.913682]  ? __x64_sys_write+0x19/0x20
[13670.913684]  ? do_syscall_64+0x6b/0xe0
[13670.913686]  ? sysvec_apic_timer_interrupt+0x66/0xd0
[13670.913689]  entry_SYSCALL_64_after_hwframe+0x6e/0x76

>
> Changes for v6:
>   - Fix build warning of printk() on 32-bit system.
>   - Fix read/write judgment in exfat_direct_IO().
>   - Remove update ei->valid_size in exfat_file_zeroed_range().
>
> Changes for v5:
>   - do not call exfat_map_new_buffer() if iblock + max_blocks < valid_blks.
>   - Reorganized the logic of exfat_get_block(), both writing and reading
> use
>     block index judgment.
>   - Remove unnecessary code moves.
>   - Reduce sync in exfat_file_write_iter()
>
> Changes for v4:
>   - Rebase for linux-6.7-rc1
>   - Use block_write_begin() instead of cont_write_begin() in
> exfat_write_begin()
>   - In exfat_cont_expand(), use ei->i_size_ondisk instead of i_size_read()
> to
>     get the number of clusters of the file.
>
> Changes for v3:
>   - Rebase to linux-6.6
>   - Move update ->valid_size from exfat_file_write_iter() to
> exfat_write_end()
>   - Use block_write_begin() instead of exfat_write_begin() in
> exfat_file_zeroed_range()
>   - Remove exfat_expand_and_zero()
>
> Changes for v2:
>   - Fix race when checking i_size on direct i/o read
>
> Yuezhang Mo (2):
>   exfat: change to get file size from DataLength
>   exfat: do not zero the extended part
>
> Yuezhang Mo (2):
>   exfat: change to get file size from DataLength
>   exfat: do not zero the extended part
>
>  fs/exfat/exfat_fs.h |   2 +
>  fs/exfat/file.c     | 193 +++++++++++++++++++++++++++++++++++++++-----
>  fs/exfat/inode.c    | 136 +++++++++++++++++++++++++++----
>  fs/exfat/namei.c    |   6 ++
>  4 files changed, 299 insertions(+), 38 deletions(-)
>
> --
> 2.25.1
>