xfs: perag initialization should only touch m_ag_max_usable for AG 0

We call __xfs_ag_resv_init to make a per-AG reservation for each AG.
This makes the reservation per-AG, not per-filesystem.  Therefore, it
is incorrect to adjust m_ag_max_usable for each AG.  Adjust it only
when we're reserving AG 0's blocks so that we only do it once per fs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
This commit is contained in:
Darrick J. Wong 2017-09-18 09:42:09 -07:00
parent ee70daaba8
commit 9789dd9e1d

View file

@ -156,7 +156,8 @@ __xfs_ag_resv_free(
trace_xfs_ag_resv_free(pag, type, 0);
resv = xfs_perag_resv(pag, type);
pag->pag_mount->m_ag_max_usable += resv->ar_asked;
if (pag->pag_agno == 0)
pag->pag_mount->m_ag_max_usable += resv->ar_asked;
/*
* AGFL blocks are always considered "free", so whatever
* was reserved at mount time must be given back at umount.
@ -216,7 +217,14 @@ __xfs_ag_resv_init(
return error;
}
mp->m_ag_max_usable -= ask;
/*
* Reduce the maximum per-AG allocation length by however much we're
* trying to reserve for an AG. Since this is a filesystem-wide
* counter, we only make the adjustment for AG 0. This assumes that
* there aren't any AGs hungrier for per-AG reservation than AG 0.
*/
if (pag->pag_agno == 0)
mp->m_ag_max_usable -= ask;
resv = xfs_perag_resv(pag, type);
resv->ar_asked = ask;