There is a deadlock between sb_internal lock (sb_start_intwrite()) and dquot related lock. It's because we call f2fs_truncate(), which eventually calls dquot_initialize(), while holding sb_internal lock. So, I called dquot_initialize() in advance to make the 2nd calling of it in f2fs_truncate() ineffective. This is similar with the thing in f2fs_evict_inode() in inode.c
Thanks, On Thu, Oct 21, 2021 at 5:11 AM Chao Yu <[email protected]> wrote: > > On 2021/10/15 3:05, Daeho Jeong wrote: > > From: Daeho Jeong <[email protected]> > > > > We detected the below circular locking dependency between sb_internal > > and fs_reclaim. So, removed it by calling dquot_initialize() before > > sb_start_intwrite(). > > > > ====================================================== > > WARNING: possible circular locking dependency detected > > ------------------------------------------------------ > > kswapd0/133 is trying to acquire lock: > > ffffff80d5fb9680 (sb_internal#2){.+.+}-{0:0}, at: evict+0xd4/0x2f8 > > > > but task is already holding lock: > > ffffffda597c93a8 (fs_reclaim){+.+.}-{0:0}, at: > > __fs_reclaim_acquire+0x4/0x50 > > > > which lock already depends on the new lock. > > ... > > other info that might help us debug this: > > > > Chain exists of: > > > > sb_internal#2 --> &s->s_dquot.dqio_sem --> fs_reclaim > > > > Possible unsafe locking scenario: > > > > CPU0 CPU1 > > ---- ---- > > lock(fs_reclaim); > > lock(&s->s_dquot.dqio_sem); > > lock(fs_reclaim); > > lock(sb_internal#2); > > Sorry, I still didn't get the root cause of this deadlock issue, could > you please explain more about this? > > And why calling dquot_initialize() in drop_inode() could break the > circular locking dependency? > > Thanks, > > > > > Signed-off-by: Daeho Jeong <[email protected]> > > --- > > fs/f2fs/super.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > > index 86eeb019cc52..a133932333c5 100644 > > --- a/fs/f2fs/super.c > > +++ b/fs/f2fs/super.c > > @@ -1370,6 +1370,8 @@ static int f2fs_drop_inode(struct inode *inode) > > /* should remain fi->extent_tree for writepage */ > > f2fs_destroy_extent_node(inode); > > > > + dquot_initialize(inode); > > + > > sb_start_intwrite(inode->i_sb); > > f2fs_i_size_write(inode, 0); > > > > _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
