Re: [PATCH 5/6] misc: add module reloading helpers

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, Oct 26, 2017 at 02:43:13PM +0800, Eryu Guan wrote:
> On Wed, Oct 25, 2017 at 10:52:04PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Add some helper functions to require that we can reload a given module,
> > and add a helper to actually do that.  Refactor the existing users to
> > use the generics.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  common/btrfs    |   12 ------------
> >  common/rc       |   15 +++++++++++++++
> >  tests/btrfs/124 |    9 +++------
> >  tests/btrfs/125 |    9 +++------
> >  4 files changed, 21 insertions(+), 24 deletions(-)
> > 
> > 
> > diff --git a/common/btrfs b/common/btrfs
> > index fd762ef..c09206c 100644
> > --- a/common/btrfs
> > +++ b/common/btrfs
> > @@ -349,18 +349,6 @@ _btrfs_qgroup_units()
> >  	$BTRFS_UTIL_PROG qgroup show --help 2>&1 | grep -q -- --raw && echo "--raw"
> >  }
> >  
> > -_require_btrfs_loadable()
> > -{
> > -	modprobe -r btrfs || _notrun "btrfs unloadable"
> > -	modprobe btrfs || _notrun "Can't load btrfs"
> > -}
> > -
> > -_reload_btrfs_ko()
> > -{
> > -	modprobe -r btrfs || _fail "btrfs unload failed"
> > -	modprobe btrfs || _fail "btrfs load failed"
> > -}
> > -
> >  _btrfs_compression_algos()
> >  {
> >  	echo zlib
> > diff --git a/common/rc b/common/rc
> > index 83aaced..5375f7b 100644
> > --- a/common/rc
> > +++ b/common/rc
> > @@ -3580,6 +3580,21 @@ _require_scratch_feature()
> >  	esac
> >  }
> >  
> > +# Check that we have a module that can be loaded.
> > +_require_loadable_module()
> > +{
> > +	module="$1"
> > +	modinfo "$module" > /dev/null 2>&1 || _notrun "${module}: must be a module."
> 
> I think we should try to unload the given module too to see if we really
> could unload it, otherwise a later _reload_module() still fails if
> rootfs is mounted as $module type, even if we already umounted TEST_DEV
> and SCRATCH_DEV.

Yeah, ok.  While I'm at it I'll drag all the module helpers out into a
separate file too.

--D

> > +}
> > +
> > +# Reload a particular module.
> > +_reload_module()
> > +{
> > +	module="$1"
> > +
> > +	modprobe -r "${module}" || _fail "${module} unload failed"
> > +	modprobe "${module}" || _fail "${module} load failed"
> > +}
> >  
> >  init_rc
> >  
> > diff --git a/tests/btrfs/124 b/tests/btrfs/124
> > index 7206094..1b6cb24 100755
> > --- a/tests/btrfs/124
> > +++ b/tests/btrfs/124
> > @@ -64,10 +64,7 @@ rm -f $seqres.full
> >  _supported_fs btrfs
> >  _supported_os Linux
> >  _require_scratch_dev_pool 2
> > -
> > -# the mounted test dir prevent btrfs unload, we need to unmount
> > -_test_unmount
> > -_require_btrfs_loadable
> > +_require_loadable_module "btrfs"
> 
> Then keep the above comments and _test_unmount?
> 
> Thanks,
> Eryu
> 
> >  
> >  _scratch_dev_pool_get 2
> >  
> > @@ -102,7 +99,7 @@ echo "clean btrfs ko" >> $seqres.full
> >  _scratch_unmount
> >  
> >  # un-scan the btrfs devices
> > -_reload_btrfs_ko
> > +_reload_module "btrfs"
> >  
> >  echo >> $seqres.full
> >  echo "-----Write degraded mount fill upto $max_fs_sz bytes-----" >> $seqres.full
> > @@ -141,7 +138,7 @@ echo
> >  echo "Mount degraded with the other dev"
> >  _scratch_unmount
> >  # un-scan the btrfs devices
> > -_reload_btrfs_ko
> > +_reload_module "btrfs"
> >  _mount -o degraded $dev2 $SCRATCH_MNT >>$seqres.full 2>&1
> >  _run_btrfs_util_prog filesystem show
> >  checkpoint3=`md5sum $SCRATCH_MNT/tf2`
> > diff --git a/tests/btrfs/125 b/tests/btrfs/125
> > index 91aa8d8..dbb226c 100755
> > --- a/tests/btrfs/125
> > +++ b/tests/btrfs/125
> > @@ -63,10 +63,7 @@ rm -f $seqres.full
> >  _supported_fs btrfs
> >  _supported_os Linux
> >  _require_scratch_dev_pool 3
> > -
> > -# we need btrfs to unload, need test dir unmounted
> > -_test_unmount
> > -_require_btrfs_loadable
> > +_require_loadable_module "btrfs"
> >  
> >  _scratch_dev_pool_get 3
> >  
> > @@ -118,7 +115,7 @@ echo "unmount" >> $seqres.full
> >  _scratch_unmount
> >  echo "clean btrfs ko" >> $seqres.full
> >  # un-scan the btrfs devices
> > -_reload_btrfs_ko
> > +_reload_module "btrfs"
> >  _mount -o degraded,device=$dev2 $dev1 $SCRATCH_MNT >>$seqres.full 2>&1
> >  dd if=/dev/zero of="$SCRATCH_MNT"/tf2 bs=$bs count=$count \
> >  					>>$seqres.full 2>&1
> > @@ -154,7 +151,7 @@ echo "Mount degraded but with other dev"
> >  
> >  _scratch_unmount
> >  # un-scan the btrfs devices
> > -_reload_btrfs_ko
> > +_reload_module "btrfs"
> >  
> >  _mount -o degraded,device=${dev2} $dev3 $SCRATCH_MNT >>$seqres.full 2>&1
> >  
> > 
> --
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