On 03/22, Light Hsieh (謝明燈) wrote: > I don't see my added log in sb_free_unlock() which will invoke > percpu_up_write to release the write semaphore.
May I ask more details whether thaw_super() was called or not? > > > ________________________________ > 寄件者: Jaegeuk Kim <jaeg...@kernel.org> > 寄件日期: 2024年3月22日 上午 08:29 > 收件者: Hillf Danton <hdan...@sina.com> > 副本: linux-ker...@vger.kernel.org <linux-ker...@vger.kernel.org>; Light Hsieh > (謝明燈) <light.hs...@mediatek.com>; linux-f2fs-devel@lists.sourceforge.net > <linux-f2fs-devel@lists.sourceforge.net> > 主旨: Re: [PATCH] f2fs: avoid the deadlock case when stopping discard thread > > > External email : Please do not click links or open attachments until you have > verified the sender or the content. > > On 03/22, Hillf Danton wrote: > > On Tue, 19 Mar 2024 17:14:42 -0700 Jaegeuk Kim <jaeg...@kernel.org> > > > f2fs_ioc_shutdown(F2FS_GOING_DOWN_NOSYNC) issue_discard_thread > > > - mnt_want_write_file() > > > - sb_start_write(SB_FREEZE_WRITE) > > __sb_start_write() > > percpu_down_read() > > > - > > > sb_start_intwrite(SB_FREEZE_FS); > > __sb_start_write() > > percpu_down_read() > > > > Given lock acquirers for read on both sides, wtf deadlock are you fixing? > > Damn. I couldn't think _write uses _read sem. > > > > > > - f2fs_stop_checkpoint(sbi, false, : waiting > > > STOP_CP_REASON_SHUTDOWN); > > > - f2fs_stop_discard_thread(sbi); > > > - kthread_stop() > > > : waiting > > > > > > - mnt_drop_write_file(filp); > > > > More important, feel free to add in spin. > > I posted this patch before Light reported. > > And, in the report, I didn't get this: > > f2fs_ioc_shutdown() --> freeze_bdev() --> freeze_super() --> > sb_wait_write(sb, SB_FREEZE_FS) --> ... ->percpu_down_write(). > > because f2fs_ioc_shutdown() calls f2fs_stop_discard_thread() after thaw_bdev() > like this order. > > -> freeze_bdev() > -> thaw_bdev() > -> f2fs_stop_discard_thread() > > Am I missing something? > > > > > Reported-by: "Light Hsieh (謝明燈)" <light.hs...@mediatek.com> > _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
