xfs: give xfs_extfree_intent its own perag reference

Give the xfs_extfree_intent an passive reference to the perag structure
data.  This reference will be used to enable scrub intent draining
functionality in subsequent patches.  The space being freed must already
be allocated, so we need to able to run even if the AG is being offlined
or shrunk.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

1 files changed, 38 insertions, 20 deletions

diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index c1aae07467c9..38b66fcfddc8 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -350,10 +350,7 @@ xfs_trans_free_extent(
 	struct xfs_owner_info		oinfo = { };
 	struct xfs_mount		*mp = tp->t_mountp;
 	struct xfs_extent		*extp;
-	struct xfs_perag		*pag;
 	uint				next_extent;
-	xfs_agnumber_t			agno = XFS_FSB_TO_AGNO(mp,
-							xefi->xefi_startblock);
 	xfs_agblock_t			agbno = XFS_FSB_TO_AGBNO(mp,
 							xefi->xefi_startblock);
 	int				error;
@@ -364,14 +361,12 @@ xfs_trans_free_extent(
 	if (xefi->xefi_flags & XFS_EFI_BMBT_BLOCK)
 		oinfo.oi_flags |= XFS_OWNER_INFO_BMBT_BLOCK;
 
-	trace_xfs_bmap_free_deferred(tp->t_mountp, agno, 0, agbno,
-			xefi->xefi_blockcount);
+	trace_xfs_bmap_free_deferred(tp->t_mountp, xefi->xefi_pag->pag_agno, 0,
+			agbno, xefi->xefi_blockcount);
 
-	pag = xfs_perag_get(mp, agno);
-	error = __xfs_free_extent(tp, pag, agbno, xefi->xefi_blockcount,
-			&oinfo, XFS_AG_RESV_NONE,
+	error = __xfs_free_extent(tp, xefi->xefi_pag, agbno,
+			xefi->xefi_blockcount, &oinfo, XFS_AG_RESV_NONE,
 			xefi->xefi_flags & XFS_EFI_SKIP_DISCARD);
-	xfs_perag_put(pag);
 
 	/*
 	 * Mark the transaction dirty, even on error. This ensures the
@@ -400,14 +395,13 @@ xfs_extent_free_diff_items(
 	const struct list_head		*a,
 	const struct list_head		*b)
 {
-	struct xfs_mount		*mp = priv;
 	struct xfs_extent_free_item	*ra;
 	struct xfs_extent_free_item	*rb;
 
 	ra = container_of(a, struct xfs_extent_free_item, xefi_list);
 	rb = container_of(b, struct xfs_extent_free_item, xefi_list);
-	return  XFS_FSB_TO_AGNO(mp, ra->xefi_startblock) -
-		XFS_FSB_TO_AGNO(mp, rb->xefi_startblock);
+
+	return ra->xefi_pag->pag_agno - rb->xefi_pag->pag_agno;
 }
 
 /* Log a free extent to the intent item. */
@@ -466,6 +460,26 @@ xfs_extent_free_create_done(
 	return &xfs_trans_get_efd(tp, EFI_ITEM(intent), count)->efd_item;
 }
 
+/* Take a passive ref to the AG containing the space we're freeing. */
+void
+xfs_extent_free_get_group(
+	struct xfs_mount		*mp,
+	struct xfs_extent_free_item	*xefi)
+{
+	xfs_agnumber_t			agno;
+
+	agno = XFS_FSB_TO_AGNO(mp, xefi->xefi_startblock);
+	xefi->xefi_pag = xfs_perag_get(mp, agno);
+}
+
+/* Release a passive AG ref after some freeing work. */
+static inline void
+xfs_extent_free_put_group(
+	struct xfs_extent_free_item	*xefi)
+{
+	xfs_perag_put(xefi->xefi_pag);
+}
+
 /* Process a free extent. */
 STATIC int
 xfs_extent_free_finish_item(
@@ -480,6 +494,8 @@ xfs_extent_free_finish_item(
 	xefi = container_of(item, struct xfs_extent_free_item, xefi_list);
 
 	error = xfs_trans_free_extent(tp, EFD_ITEM(done), xefi);
+
+	xfs_extent_free_put_group(xefi);
 	kmem_cache_free(xfs_extfree_item_cache, xefi);
 	return error;
 }
@@ -500,6 +516,8 @@ xfs_extent_free_cancel_item(
 	struct xfs_extent_free_item	*xefi;
 
 	xefi = container_of(item, struct xfs_extent_free_item, xefi_list);
+
+	xfs_extent_free_put_group(xefi);
 	kmem_cache_free(xfs_extfree_item_cache, xefi);
 }
 
@@ -530,24 +548,21 @@ xfs_agfl_free_finish_item(
 	struct xfs_extent		*extp;
 	struct xfs_buf			*agbp;
 	int				error;
-	xfs_agnumber_t			agno;
 	xfs_agblock_t			agbno;
 	uint				next_extent;
-	struct xfs_perag		*pag;
 
 	xefi = container_of(item, struct xfs_extent_free_item, xefi_list);
 	ASSERT(xefi->xefi_blockcount == 1);
-	agno = XFS_FSB_TO_AGNO(mp, xefi->xefi_startblock);
 	agbno = XFS_FSB_TO_AGBNO(mp, xefi->xefi_startblock);
 	oinfo.oi_owner = xefi->xefi_owner;
 
-	trace_xfs_agfl_free_deferred(mp, agno, 0, agbno, xefi->xefi_blockcount);
+	trace_xfs_agfl_free_deferred(mp, xefi->xefi_pag->pag_agno, 0, agbno,
+			xefi->xefi_blockcount);
 
-	pag = xfs_perag_get(mp, agno);
-	error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
+	error = xfs_alloc_read_agf(xefi->xefi_pag, tp, 0, &agbp);
 	if (!error)
-		error = xfs_free_agfl_block(tp, agno, agbno, agbp, &oinfo);
-	xfs_perag_put(pag);
+		error = xfs_free_agfl_block(tp, xefi->xefi_pag->pag_agno,
+				agbno, agbp, &oinfo);
 
 	/*
 	 * Mark the transaction dirty, even on error. This ensures the
@@ -566,6 +581,7 @@ xfs_agfl_free_finish_item(
 	extp->ext_len = xefi->xefi_blockcount;
 	efdp->efd_next_extent++;
 
+	xfs_extent_free_put_group(xefi);
 	kmem_cache_free(xfs_extfree_item_cache, xefi);
 	return error;
 }
@@ -636,7 +652,9 @@ xfs_efi_item_recover(
 		fake.xefi_startblock = extp->ext_start;
 		fake.xefi_blockcount = extp->ext_len;
 
+		xfs_extent_free_get_group(mp, &fake);
 		error = xfs_trans_free_extent(tp, efdp, &fake);
+		xfs_extent_free_put_group(&fake);
 		if (error == -EFSCORRUPTED)
 			XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp,
 					extp, sizeof(*extp));