xfs: merge the perag freeing helpers

There is no good reason to have two different routines for freeing perag
structures for the unmount and error cases.  Add two arguments to specify
the range of AGs to free to xfs_free_perag, and use that to replace
xfs_free_unused_perag_range.

The addition RCU grace period for the error case is harmless, and the
extra check for the AG to actually exist is not required now that the
callers pass the exact known allocated range.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

Author: Christoph Hellwig

fs/xfs/libxfs/xfs_ag.c

@@ -185,17 +185,20 @@ xfs_initialize_perag_data(
 }
 
 /*
- * Free up the per-ag resources associated with the mount structure.
+ * Free up the per-ag resources  within the specified AG range.
  */
 void
-xfs_free_perag(
-	struct xfs_mount	*mp)
+xfs_free_perag_range(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		first_agno,
+	xfs_agnumber_t		end_agno)
+
 {
-	struct xfs_perag	*pag;
 	xfs_agnumber_t		agno;
 
-	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
-		pag = xa_erase(&mp->m_perags, agno);
+	for (agno = first_agno; agno < end_agno; agno++) {
+		struct xfs_perag	*pag = xa_erase(&mp->m_perags, agno);
+
 		ASSERT(pag);
 		XFS_IS_CORRUPT(pag->pag_mount, atomic_read(&pag->pag_ref) != 0);
 		xfs_defer_drain_free(&pag->pag_intents_drain);
@@ -270,29 +273,6 @@ xfs_agino_range(
 	return __xfs_agino_range(mp, xfs_ag_block_count(mp, agno), first, last);
 }
 
-/*
- * Free perag within the specified AG range, it is only used to free unused
- * perags under the error handling path.
- */
-void
-xfs_free_unused_perag_range(
-	struct xfs_mount	*mp,
-	xfs_agnumber_t		agstart,
-	xfs_agnumber_t		agend)
-{
-	struct xfs_perag	*pag;
-	xfs_agnumber_t		index;
-
-	for (index = agstart; index < agend; index++) {
-		pag = xa_erase(&mp->m_perags, index);
-		if (!pag)
-			break;
-		xfs_buf_cache_destroy(&pag->pag_bcache);
-		xfs_defer_drain_free(&pag->pag_intents_drain);
-		kfree(pag);
-	}
-}
-
 int
 xfs_initialize_perag(
 	struct xfs_mount	*mp,
@@ -366,7 +346,7 @@ xfs_initialize_perag(
 out_free_pag:
 	kfree(pag);
 out_unwind_new_pags:
-	xfs_free_unused_perag_range(mp, old_agcount, index);
+	xfs_free_perag_range(mp, old_agcount, index);
 	return error;
 }
 

fs/xfs/libxfs/xfs_ag.h

@@ -144,13 +144,12 @@ __XFS_AG_OPSTATE(prefers_metadata, PREFERS_METADATA)
 __XFS_AG_OPSTATE(allows_inodes, ALLOWS_INODES)
 __XFS_AG_OPSTATE(agfl_needs_reset, AGFL_NEEDS_RESET)
 
-void xfs_free_unused_perag_range(struct xfs_mount *mp, xfs_agnumber_t agstart,
-			xfs_agnumber_t agend);
 int xfs_initialize_perag(struct xfs_mount *mp, xfs_agnumber_t old_agcount,
 		xfs_agnumber_t agcount, xfs_rfsblock_t dcount,
 		xfs_agnumber_t *maxagi);
+void xfs_free_perag_range(struct xfs_mount *mp, xfs_agnumber_t first_agno,
+		xfs_agnumber_t end_agno);
 int xfs_initialize_perag_data(struct xfs_mount *mp, xfs_agnumber_t agno);
-void xfs_free_perag(struct xfs_mount *mp);
 
 /* Passive AG references */
 struct xfs_perag *xfs_perag_get(struct xfs_mount *mp, xfs_agnumber_t agno);

fs/xfs/xfs_fsops.c

@@ -229,7 +229,7 @@ xfs_growfs_data_private(
 	xfs_trans_cancel(tp);
 out_free_unused_perag:
 	if (nagcount > oagcount)
-		xfs_free_unused_perag_range(mp, oagcount, nagcount);
+		xfs_free_perag_range(mp, oagcount, nagcount);
 	return error;
 }
 

fs/xfs/xfs_mount.c

@@ -1048,7 +1048,7 @@ xfs_mountfs(
 		xfs_buftarg_drain(mp->m_logdev_targp);
 	xfs_buftarg_drain(mp->m_ddev_targp);
  out_free_perag:
-	xfs_free_perag(mp);
+	xfs_free_perag_range(mp, 0, mp->m_sb.sb_agcount);
  out_free_dir:
 	xfs_da_unmount(mp);
  out_remove_uuid:
@@ -1129,8 +1129,7 @@ xfs_unmountfs(
 	xfs_errortag_clearall(mp);
 #endif
 	shrinker_free(mp->m_inodegc_shrinker);
-	xfs_free_perag(mp);
-
+	xfs_free_perag_range(mp, 0, mp->m_sb.sb_agcount);
 	xfs_errortag_del(mp);
 	xfs_error_sysfs_del(mp);
 	xchk_stats_unregister(mp->m_scrub_stats);