On Fri, Jan 24, 2020 at 01:00:54PM +1100, Dave Chinner wrote:
> On Wed, Jan 22, 2020 at 11:42:54PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> >
> > Refactor xfs_read_agf and xfs_alloc_read_agf to return EAGAIN if the
> > caller passed TRYLOCK and we weren't able to get the lock; and change
> > the callers to recognize this.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > ---
> > fs/xfs/libxfs/xfs_alloc.c | 34 +++++++++++++++-------------------
> > fs/xfs/libxfs/xfs_bmap.c | 11 ++++++-----
> > fs/xfs/xfs_filestream.c | 11 ++++++-----
> > 3 files changed, 27 insertions(+), 29 deletions(-)
> .....
> > @@ -2992,10 +2987,11 @@ xfs_alloc_read_agf(
> > error = xfs_read_agf(mp, tp, agno,
> > (flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
> > bpp);
> > - if (error)
> > + if (error) {
> > + /* We don't support trylock when freeing. */
> > + ASSERT(error != -EAGAIN || !(flags & XFS_ALLOC_FLAG_FREEING));
> > return error;
>
> Shouldn't we check this with asserts before we call xfs_read_agf()?
> i.e.
>
> /* We don't support trylock when freeing. */
> ASSERT((flags & (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)) !=
> (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK));
> ....
Yeah.
> > - if (!*bpp)
> > - return 0;
> > + }
> > ASSERT(!(*bpp)->b_error);
> >
> > agf = XFS_BUF_TO_AGF(*bpp);
> > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> > index cfcef076c72f..9a6d7a84689a 100644
> > --- a/fs/xfs/libxfs/xfs_bmap.c
> > +++ b/fs/xfs/libxfs/xfs_bmap.c
> > @@ -3311,11 +3311,12 @@ xfs_bmap_longest_free_extent(
> > pag = xfs_perag_get(mp, ag);
> > if (!pag->pagf_init) {
> > error = xfs_alloc_pagf_init(mp, tp, ag, XFS_ALLOC_FLAG_TRYLOCK);
> > - if (error)
> > - goto out;
> > -
> > - if (!pag->pagf_init) {
> > - *notinit = 1;
> > + if (error) {
> > + /* Couldn't lock the AGF, so skip this AG. */
> > + if (error == -EAGAIN) {
> > + *notinit = 1;
> > + error = 0;
> > + }
> > goto out;
> > }
> > }
> > diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
> > index 5f12b5d8527a..3ccdab463359 100644
> > --- a/fs/xfs/xfs_filestream.c
> > +++ b/fs/xfs/xfs_filestream.c
> > @@ -159,16 +159,17 @@ xfs_filestream_pick_ag(
> >
> > if (!pag->pagf_init) {
> > err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
> > - if (err && !trylock) {
> > + if (err == -EAGAIN) {
> > + /* Couldn't lock the AGF, skip this AG. */
> > + xfs_perag_put(pag);
> > + continue;
> > + }
> > + if (err) {
> > xfs_perag_put(pag);
> > return err;
> > }
>
> Might neater to do:
>
> if (!pag->pagf_init) {
> err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
> if (err) {
> xfs_perag_put(pag);
> if (err != -EAGAIN)
> return err;
> /* Couldn't lock the AGF, skip this AG. */
> continue;
> }
> }
>
> Otherwise it all looks ok.
Cool. Will fix.
--D
>
> -Dave
> --
> Dave Chinner
> david@xxxxxxxxxxxxx
