Messages in this thread | | | From | Chao Yu <> | Subject | RE: [PATCH 8/8] f2fs: fix to avoid deadlock between checkpoint and writepages | Date | Wed, 16 Dec 2015 10:34:22 +0800 |
| |
Hi Jaegeuk,
> -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk@kernel.org] > Sent: Wednesday, December 16, 2015 6:01 AM > To: Chao Yu > Cc: linux-f2fs-devel@lists.sourceforge.net; linux-kernel@vger.kernel.org > Subject: Re: [PATCH 8/8] f2fs: fix to avoid deadlock between checkpoint and writepages > > Hi Chao, > > On Tue, Dec 15, 2015 at 01:36:08PM +0800, Chao Yu wrote: > > This patch fixes to move f2fs_balance_fs out of sbi->writepages' > > coverage to avoid potential ABBA deadlock which was found by lockdep: > > > > Possible unsafe locking scenario: > > > > CPU0 CPU1 > > ---- ---- > > lock(&sbi->writepages); > > lock(&sbi->cp_mutex); > > lock(&sbi->writepages); > > lock(&sbi->cp_mutex); > > > > *** DEADLOCK *** > > I expect it will be fine if syncing is done by f2fs_balance_fs_bg().
Yes, I will drop this patch.
Thanks,
> > Thanks, > > > > > stack of CPU0: > > [<ffffffff810b8dd1>] __lock_acquire+0x1321/0x1770 > > [<ffffffff810b92d7>] lock_acquire+0xb7/0x130 > > [<ffffffff817ad082>] mutex_lock_nested+0x52/0x380 > > [<ffffffffa07b767b>] f2fs_balance_fs+0x8b/0xa0 [f2fs] > > [<ffffffffa07afb5b>] f2fs_write_data_page+0x33b/0x460 [f2fs] > > [<ffffffffa07ab79a>] __f2fs_writepage+0x1a/0x50 [f2fs] > > [<ffffffffa07ac693>] T.1541+0x293/0x560 [f2fs] > > [<ffffffffa07aca8c>] f2fs_write_data_pages+0x12c/0x230 [f2fs] > > [<ffffffff8118adb3>] do_writepages+0x23/0x40 > > [<ffffffff8117c545>] __filemap_fdatawrite_range+0xb5/0xf0 > > [<ffffffff8117c623>] filemap_write_and_wait_range+0xa3/0xd0 > > [<ffffffffa079cc20>] f2fs_symlink+0x180/0x300 [f2fs] > > [<ffffffff81208187>] vfs_symlink+0xb7/0xe0 > > [<ffffffff8120acc5>] SyS_symlinkat+0xc5/0x100 > > [<ffffffff81205ad6>] SyS_symlink+0x16/0x20 > > [<ffffffff817b15d7>] entry_SYSCALL_64_fastpath+0x12/0x6f > > > > stack of CPU1 > > [<ffffffff810b92d7>] lock_acquire+0xb7/0x130 > > [<ffffffff817ad082>] mutex_lock_nested+0x52/0x380 > > [<ffffffffa07aca7e>] f2fs_write_data_pages+0x11e/0x230 [f2fs] > > [<ffffffff8118adb3>] do_writepages+0x23/0x40 > > [<ffffffff8117c545>] __filemap_fdatawrite_range+0xb5/0xf0 > > [<ffffffff8117c9ef>] filemap_fdatawrite+0x1f/0x30 > > [<ffffffffa07a728d>] sync_dirty_inodes+0x4d/0xd0 [f2fs] > > [<ffffffffa07a7381>] block_operations+0x71/0x160 [f2fs] > > [<ffffffffa07a85f8>] write_checkpoint+0xe8/0xbb0 [f2fs] > > [<ffffffffa07a043f>] f2fs_sync_fs+0x8f/0xf0 [f2fs] > > [<ffffffffa07b63af>] f2fs_balance_fs_bg+0x6f/0xd0 [f2fs] > > [<ffffffffa07b1c97>] f2fs_write_node_pages+0x57/0x150 [f2fs] > > [<ffffffff8118adb3>] do_writepages+0x23/0x40 > > [<ffffffff8122c9ed>] __writeback_single_inode+0x6d/0x3d0 > > [<ffffffff8122ec87>] writeback_sb_inodes+0x2c7/0x520 > > [<ffffffff8122f193>] wb_writeback+0x133/0x330 > > [<ffffffff8122f478>] wb_do_writeback+0xe8/0x270 > > [<ffffffff8122f680>] wb_workfn+0x80/0x1f0 > > [<ffffffff81081a1c>] process_one_work+0x20c/0x5c0 > > [<ffffffff81083c62>] worker_thread+0x132/0x5f0 > > [<ffffffff8108918e>] kthread+0xde/0x100 > > [<ffffffff817b193f>] ret_from_fork+0x3f/0x70 > > > > Signed-off-by: Chao Yu <chao2.yu@samsung.com> > > --- > > fs/f2fs/data.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > > index 2e97057..985671d 100644 > > --- a/fs/f2fs/data.c > > +++ b/fs/f2fs/data.c > > @@ -506,7 +506,6 @@ static void __allocate_data_blocks(struct inode *inode, loff_t offset, > > u64 end_offset; > > > > while (len) { > > - f2fs_balance_fs(sbi); > > f2fs_lock_op(sbi); > > > > /* When reading holes, we need its node page */ > > @@ -1186,7 +1185,7 @@ out: > > if (err) > > ClearPageUptodate(page); > > unlock_page(page); > > - if (need_balance_fs) > > + if (need_balance_fs && !test_opt(sbi, DATA_FLUSH)) > > f2fs_balance_fs(sbi); > > if (wbc->for_reclaim) { > > f2fs_submit_merged_bio(sbi, DATA, WRITE); > > @@ -1617,6 +1616,8 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, > > trace_f2fs_direct_IO_enter(inode, offset, count, rw); > > > > if (rw == WRITE) { > > + f2fs_balance_fs(sbi); > > + > > if (serialized) > > mutex_lock(&sbi->writepages); > > __allocate_data_blocks(inode, offset, count); > > -- > > 2.6.3 > >
| |