Re: [PATCH v4] ntfs: serialize attribute-list replacement with lookups

[Hyunchul Lee]

2026년 7월 5일 (일) 오전 12:40, Cen Zhang <zzzccc427@xxxxxxxxx>님이 작성:
>
> Hi, Hyunchul
>
> Hyunchul Lee <hyc.lee@xxxxxxxxx> 于2026年7月3日周五 09:41写道：
> >
> > Hi Cen,
> >
> > While running generic/013 from xfstests, I observed the following hung
> > task warning:
> >
> > [  492.533956] INFO: task fsstress:934 blocked for more than 122 seconds.
> > [  492.534445]       Tainted: G           O        7.1.0-g81fe702ff176 #2
> > [  492.534870] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
> > disables this message.
> > [  492.535914] INFO: task fsstress:934 <reader> blocked on an
> > rw-semaphore likely owned by task fsstress:934 <writer>
> > [  492.536788] INFO: lockdep is turned off.
> >
> > # ps -eo pid,comm,stat | grep " D"
> >     460 kworker/u16:4+f D
> >     934 fsstress        D+
> >
> > # cat /proc/934/stack
> > [<0>] ntfs_attr_list_lock+0x2a/0x60 [ntfs]
> > [<0>] ntfs_attr_get_search_ctx+0x97/0x100 [ntfs]
> > [<0>] ntfs_resident_attr_resize+0x64/0x610 [ntfs]
> > [<0>] ntfs_ir_truncate+0x82/0x120 [ntfs]
> > [<0>] ntfs_ie_add+0x35/0x200 [ntfs]
> > [<0>] ntfs_index_add_filename+0xca/0x120 [ntfs]
> > [<0>] __ntfs_create+0xa9a/0xd80 [ntfs]
> > [<0>] ntfs_create+0xbd/0x170 [ntfs]
> > [<0>] path_openat+0x1014/0x1400
> > [<0>] do_file_open+0xdf/0x1a0
> > [<0>] do_sys_openat2+0x7b/0xe0
> > [<0>] __x64_sys_creat+0x45/0x70
> > [<0>] do_syscall_64+0x101/0x6a0
> > [<0>] entry_SYSCALL_64_after_hwframe+0x77/0x7f
> >
> > # cat /proc/460/stack
> > [<0>] __ntfs_write_inode+0x7b/0x6b0 [ntfs]
> > [<0>] __writeback_single_inode+0x3f1/0x580
> > [<0>] writeback_sb_inodes+0x25b/0x8c0
> > [<0>] __writeback_inodes_wb+0x47/0xf0
> > [<0>] wb_writeback+0x216/0x440
> > [<0>] wb_workfn+0x3e6/0x510
> > [<0>] process_one_work+0x200/0x5e0
> > [<0>] worker_thread+0x1a0/0x370
> > [<0>] kthread+0xef/0x120
> > [<0>] ret_from_fork+0x270/0x330
> > [<0>] ret_from_fork_asm+0x1a/0x30
>
> Thanks for the review and test.
>
> I tried to solve this crash, then kept refining the locking after testing
> it with xfstests.  During that process I ran into more and more issues,
> which forced me to keep changing and expanding the patch.  As a result,
> the current patch has become quite large and complex, although I have not
> found new issues with the current version under xfstests.
>
> However, this version was also prepared with LLM assistance, and although
> I reviewed and tested the result, I am not fully confident that this is
> already the best or complete solution.  I am therefore sending it as an RFC
> first.  I would appreciate your review on whether this direction and lock
> ordering look reasonable, or whether you would prefer a smaller/different
> approach.  It would also be great if you could help solve this together;
> I may have made it more complicated than it needed to be.

Could you summarize what issues were found and how they were resolved?

There are so many changes in the v5 patch, it is difficult to understand the
overall picture.

>
> Best Regards,
> Cen Zhang



-- 
Thanks,
Hyunchul