xfs: perag initialization should only touch m_ag_max_usable for AG 0 (9789dd9e) · Commits · 戴 / test

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>

fs/xfs/libxfs/xfs_ag_resv.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -156,6 +156,7 @@ __xfs_ag_resv_free(
		trace_xfs_ag_resv_free(pag, type, 0);

		resv = xfs_perag_resv(pag, type);
		if (pag->pag_agno == 0)
		pag->pag_mount->m_ag_max_usable += resv->ar_asked;
		/*
		* AGFL blocks are always considered "free", so whatever
		@@ -216,6 +217,13 @@ __xfs_ag_resv_init(
		return error;
		}

		/*
		* 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);

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