Hi I am wondering why does do_resume need to call dm_suspend at all. Does anyone here remember why is this code path needed?
Mikulas On Wed, 17 Jul 2024, Khazhismel Kumykov wrote: > do_resume when loading a new map first calls dm_suspend, which could > silently fail. When we proceeded to dm_swap_table, we would bail out > with EINVAL. Instead, restore new_map and return ERESTARTSYS when > signaled. > > Signed-off-by: Khazhismel Kumykov <[email protected]> > --- > drivers/md/dm-ioctl.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) > > > RFC as I am rather unfamiliar with the locking semantics here - whether > we do need to re-grab hash_lock to write to an hc we previously grabbed, > and whether the device becoming unhashed while we're in this function is > really something that needs to be checked. However, this patch does fix > the issue we were seeing - we'd get EINVAL when thread in ioctl was > signaled. > > > diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c > index c2c07bfa6471..b81650c6d096 100644 > --- a/drivers/md/dm-ioctl.c > +++ b/drivers/md/dm-ioctl.c > @@ -1181,8 +1181,22 @@ static int do_resume(struct dm_ioctl *param) > suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; > if (param->flags & DM_NOFLUSH_FLAG) > suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG; > - if (!dm_suspended_md(md)) > - dm_suspend(md, suspend_flags); > + if (!dm_suspended_md(md)) { > + r = dm_suspend(md, suspend_flags); > + if (r == -EINTR) > + r = -ERESTARTSYS; > + if (r) { > + down_write(&_hash_lock); > + hc = dm_get_mdptr(md); > + if (!hc) > + r = -ENXIO; > + else > + hc->new_map = new_map; > + up_write(&_hash_lock); > + dm_put(md); > + return r; > + } > + } > > old_size = dm_get_size(md); > old_map = dm_swap_table(md, new_map); > -- > 2.45.2.993.g49e7a77208-goog >
