On Fri, Oct 25, 2019 at 09:35:17AM -0700, Darrick J. Wong wrote:
> On Fri, Oct 25, 2019 at 10:22:27AM -0400, Brian Foster wrote:
> > On Wed, Oct 09, 2019 at 09:49:59AM -0700, Darrick J. Wong wrote:
> > > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > >
> > > Create a new xrep_newbt structure to encapsulate a fake root for
> > > creating a staged btree cursor as well as to track all the blocks that
> > > we need to reserve in order to build that btree.
> > >
> > > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > > ---
> > > fs/xfs/scrub/repair.c | 260 +++++++++++++++++++++++++++++++++++++++++++++++++
> > > fs/xfs/scrub/repair.h | 61 +++++++++++
> > > fs/xfs/scrub/trace.h | 58 +++++++++++
> > > 3 files changed, 379 insertions(+)
> > >
> > >
> > > diff --git a/fs/xfs/scrub/repair.c b/fs/xfs/scrub/repair.c
> > > index 588bc054db5c..beebd484c5f3 100644
> > > --- a/fs/xfs/scrub/repair.c
> > > +++ b/fs/xfs/scrub/repair.c
> > > @@ -359,6 +359,266 @@ xrep_init_btblock(
> > > return 0;
> > > }
> > >
> > ...
> > > +/* Initialize accounting resources for staging a new inode fork btree. */
> > > +void
> > > +xrep_newbt_init_inode(
> > > + struct xrep_newbt *xnr,
> > > + struct xfs_scrub *sc,
> > > + int whichfork,
> > > + const struct xfs_owner_info *oinfo)
> > > +{
> > > + memset(xnr, 0, sizeof(struct xrep_newbt));
> > > + xnr->sc = sc;
> > > + xnr->oinfo = *oinfo; /* structure copy */
> > > + xnr->alloc_hint = XFS_INO_TO_FSB(sc->mp, sc->ip->i_ino);
> > > + xnr->resv = XFS_AG_RESV_NONE;
> > > + xnr->ifake.if_fork = kmem_zone_zalloc(xfs_ifork_zone, 0);
> > > + xnr->ifake.if_fork_size = XFS_IFORK_SIZE(sc->ip, whichfork);
> > > + INIT_LIST_HEAD(&xnr->reservations);
> >
> > Looks like this could reuse the above function for everything outside of
> > the fake root bits.
>
> Ok.
>
> > > +}
> > > +
> > > +/*
> > > + * Initialize accounting resources for staging a new btree. Callers are
> > > + * expected to add their own reservations (and clean them up) manually.
> > > + */
> > > +void
> > > +xrep_newbt_init_bare(
> > > + struct xrep_newbt *xnr,
> > > + struct xfs_scrub *sc)
> > > +{
> > > + xrep_newbt_init_ag(xnr, sc, &XFS_RMAP_OINFO_ANY_OWNER, NULLFSBLOCK,
> > > + XFS_AG_RESV_NONE);
> > > +}
> > > +
> > > +/* Add a space reservation manually. */
> > > +int
> > > +xrep_newbt_add_reservation(
> > > + struct xrep_newbt *xnr,
> > > + xfs_fsblock_t fsbno,
> > > + xfs_extlen_t len)
> > > +{
> >
> > FWIW the "reservation" terminology sounds a bit funny to me. Perhaps
> > it's just because I've had log reservation on my mind :P, but something
> > that "reserves blocks" as opposed to "adds reservation" might be a bit
> > more clear from a naming perspective.
>
> xrep_newbt_reserve_space() ?
>
> I feel that's a little awkward since it's not actually reserving
> anything; all it's doing is some accounting work for some space that the
> caller already allocated. But it's probably no worse than the current
> name. :)
>
Maybe _add_blocks() and _alloc_blocks() for these two and something like
_[get|use]_block() in the later helper that populates the btree..? That
seems more descriptive to me than "reservation" and "space," but that's
just my .02.
Brian
> > > + struct xrep_newbt_resv *resv;
> > > +
> > > + resv = kmem_alloc(sizeof(struct xrep_newbt_resv), KM_MAYFAIL);
> > > + if (!resv)
> > > + return -ENOMEM;
> > > +
> > > + INIT_LIST_HEAD(&resv->list);
> > > + resv->fsbno = fsbno;
> > > + resv->len = len;
> > > + resv->used = 0;
> >
> > Is ->used purely a count or does it also serve as a pointer to the next
> > "unused" block?
>
> It's a counter, as documented in the struct declaration.
>
> > > + list_add_tail(&resv->list, &xnr->reservations);
> > > + return 0;
> > > +}
> > > +
> > > +/* Reserve disk space for our new btree. */
> > > +int
> > > +xrep_newbt_reserve_space(
> > > + struct xrep_newbt *xnr,
> > > + uint64_t nr_blocks)
> > > +{
> > > + struct xfs_scrub *sc = xnr->sc;
> > > + xfs_alloctype_t type;
> > > + xfs_fsblock_t alloc_hint = xnr->alloc_hint;
> > > + int error = 0;
> > > +
> > > + type = sc->ip ? XFS_ALLOCTYPE_START_BNO : XFS_ALLOCTYPE_NEAR_BNO;
> > > +
> >
> > So I take it this distinguishes between reconstruction of a bmapbt
> > where we can allocate across AGs vs an AG tree..? If so, a one liner
> > comment wouldn't hurt here.
>
> Ok.
>
> > > + while (nr_blocks > 0 && !error) {
> > > + struct xfs_alloc_arg args = {
> > > + .tp = sc->tp,
> > > + .mp = sc->mp,
> > > + .type = type,
> > > + .fsbno = alloc_hint,
> > > + .oinfo = xnr->oinfo,
> > > + .minlen = 1,
> > > + .maxlen = nr_blocks,
> > > + .prod = nr_blocks,
> >
> > Why .prod? Is this relevant if .mod isn't set?
>
> Not sure why that's even in there. :/
>
> > > + .resv = xnr->resv,
> > > + };
> > > +
> > > + error = xfs_alloc_vextent(&args);
> > > + if (error)
> > > + return error;
> > > + if (args.fsbno == NULLFSBLOCK)
> > > + return -ENOSPC;
> > > +
> > > + trace_xrep_newbt_reserve_space(sc->mp,
> > > + XFS_FSB_TO_AGNO(sc->mp, args.fsbno),
> > > + XFS_FSB_TO_AGBNO(sc->mp, args.fsbno),
> > > + args.len, xnr->oinfo.oi_owner);
> > > +
> > > + error = xrep_newbt_add_reservation(xnr, args.fsbno, args.len);
> > > + if (error)
> > > + break;
> > > +
> > > + nr_blocks -= args.len;
> > > + alloc_hint = args.fsbno + args.len - 1;
> > > +
> > > + if (sc->ip)
> > > + error = xfs_trans_roll_inode(&sc->tp, sc->ip);
> > > + else
> > > + error = xrep_roll_ag_trans(sc);
> > > + }
> > > +
> > > + return error;
> > > +}
> > > +
> > > +/* Free all the accounting info and disk space we reserved for a new btree. */
> > > +void
> > > +xrep_newbt_destroy(
> > > + struct xrep_newbt *xnr,
> > > + int error)
> > > +{
> > > + struct xfs_scrub *sc = xnr->sc;
> > > + struct xrep_newbt_resv *resv, *n;
> > > +
> > > + if (error)
> > > + goto junkit;
> > > +
> > > + list_for_each_entry_safe(resv, n, &xnr->reservations, list) {
> > > + /* Free every block we didn't use. */
> > > + resv->fsbno += resv->used;
> > > + resv->len -= resv->used;
> > > + resv->used = 0;
> >
> > That answers my count/pointer question. :)
>
> > > +
> > > + if (resv->len > 0) {
> > > + trace_xrep_newbt_unreserve_space(sc->mp,
> > > + XFS_FSB_TO_AGNO(sc->mp, resv->fsbno),
> > > + XFS_FSB_TO_AGBNO(sc->mp, resv->fsbno),
> > > + resv->len, xnr->oinfo.oi_owner);
> > > +
> > > + __xfs_bmap_add_free(sc->tp, resv->fsbno, resv->len,
> > > + &xnr->oinfo, true);
> > > + }
> > > +
> > > + list_del(&resv->list);
> > > + kmem_free(resv);
> > > + }
> > > +
> > > +junkit:
> > > + list_for_each_entry_safe(resv, n, &xnr->reservations, list) {
> > > + list_del(&resv->list);
> > > + kmem_free(resv);
> > > + }
> >
> > Seems like this could be folded into the above loop by just checking
> > error and skipping the free logic appropriately.
> >
> > > +
> > > + if (sc->ip) {
> > > + kmem_zone_free(xfs_ifork_zone, xnr->ifake.if_fork);
> > > + xnr->ifake.if_fork = NULL;
> > > + }
> > > +}
> > > +
> > > +/* Feed one of the reserved btree blocks to the bulk loader. */
> > > +int
> > > +xrep_newbt_alloc_block(
> > > + struct xfs_btree_cur *cur,
> > > + struct xrep_newbt *xnr,
> > > + union xfs_btree_ptr *ptr)
> > > +{
> > > + struct xrep_newbt_resv *resv;
> > > + xfs_fsblock_t fsb;
> > > +
> > > + /*
> > > + * If last_resv doesn't have a block for us, move forward until we find
> > > + * one that does (or run out of reservations).
> > > + */
> > > + if (xnr->last_resv == NULL) {
> > > + list_for_each_entry(resv, &xnr->reservations, list) {
> > > + if (resv->used < resv->len) {
> > > + xnr->last_resv = resv;
> > > + break;
> > > + }
> > > + }
> >
> > Not a big deal right now, but it might be worth eventually considering
> > something more efficient. For example, perhaps we could rotate depleted
> > entries to the end of the list and if we rotate and find nothing in the
> > next entry at the head, we know we've run out of space.
>
> Hm, yeah, this part would be much simpler if all we had to do was latch
> on to the head element and rotate them to the tail when we're done.
>
> >
> > > + if (xnr->last_resv == NULL)
> > > + return -ENOSPC;
> > > + } else if (xnr->last_resv->used == xnr->last_resv->len) {
> > > + if (xnr->last_resv->list.next == &xnr->reservations)
> > > + return -ENOSPC;
> > > + xnr->last_resv = list_entry(xnr->last_resv->list.next,
> > > + struct xrep_newbt_resv, list);
> > > + }
> > > +
> > > + /* Nab the block. */
> > > + fsb = xnr->last_resv->fsbno + xnr->last_resv->used;
> > > + xnr->last_resv->used++;
> > > +
> > > + trace_xrep_newbt_alloc_block(cur->bc_mp,
> > > + XFS_FSB_TO_AGNO(cur->bc_mp, fsb),
> > > + XFS_FSB_TO_AGBNO(cur->bc_mp, fsb),
> > > + xnr->oinfo.oi_owner);
> > > +
> > > + if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
> > > + ptr->l = cpu_to_be64(fsb);
> > > + else
> > > + ptr->s = cpu_to_be32(XFS_FSB_TO_AGBNO(cur->bc_mp, fsb));
> > > + return 0;
> > > +}
> > > +
> > ...
> > > diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
> > > index 479cfe38065e..ab6c1199ecc0 100644
> > > --- a/fs/xfs/scrub/repair.h
> > > +++ b/fs/xfs/scrub/repair.h
> > ...
> > > @@ -59,6 +63,63 @@ int xrep_agf(struct xfs_scrub *sc);
> > > int xrep_agfl(struct xfs_scrub *sc);
> > > int xrep_agi(struct xfs_scrub *sc);
> > >
> > ...
> > > +
> > > +#define for_each_xrep_newbt_reservation(xnr, resv, n) \
> > > + list_for_each_entry_safe((resv), (n), &(xnr)->reservations, list)
> >
> > This is unused (and seems unnecessary for a simple list).
>
> It's used by the free space rebuilder in the next patch; I suppose I
> could move it down. That said, I've been trying to keep the common code
> out of that particular patch so that the repair patches can be merged in
> any order.
>
> > ...
> > > diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
> > > index 3362bae28b46..deb177abf652 100644
> > > --- a/fs/xfs/scrub/trace.h
> > > +++ b/fs/xfs/scrub/trace.h
> > > @@ -904,6 +904,64 @@ TRACE_EVENT(xrep_ialloc_insert,
> > > __entry->freemask)
> > > )
> > >
> > ...
> > > +#define DEFINE_NEWBT_EXTENT_EVENT(name) \
> > > +DEFINE_EVENT(xrep_newbt_extent_class, name, \
> > > + TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, \
> > > + xfs_agblock_t agbno, xfs_extlen_t len, \
> > > + int64_t owner), \
> > > + TP_ARGS(mp, agno, agbno, len, owner))
> > > +DEFINE_NEWBT_EXTENT_EVENT(xrep_newbt_reserve_space);
> > > +DEFINE_NEWBT_EXTENT_EVENT(xrep_newbt_unreserve_space);
> > > +
> > > +TRACE_EVENT(xrep_newbt_alloc_block,
> > > + TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno,
> > > + xfs_agblock_t agbno, int64_t owner),
> >
> > This could be folded into the above class if we just passed 1 for the
> > length, eh?
>
> Er, yes. Fixed.
>
> --D
>
> > Brian
> >
> > > + TP_ARGS(mp, agno, agbno, owner),
> > > + TP_STRUCT__entry(
> > > + __field(dev_t, dev)
> > > + __field(xfs_agnumber_t, agno)
> > > + __field(xfs_agblock_t, agbno)
> > > + __field(int64_t, owner)
> > > + ),
> > > + TP_fast_assign(
> > > + __entry->dev = mp->m_super->s_dev;
> > > + __entry->agno = agno;
> > > + __entry->agbno = agbno;
> > > + __entry->owner = owner;
> > > + ),
> > > + TP_printk("dev %d:%d agno %u agbno %u owner %lld",
> > > + MAJOR(__entry->dev), MINOR(__entry->dev),
> > > + __entry->agno,
> > > + __entry->agbno,
> > > + __entry->owner)
> > > +);
> > > +
> > > #endif /* IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR) */
> > >
> > > #endif /* _TRACE_XFS_SCRUB_TRACE_H */
> > >
> >
