xfs: create simplified inode walk function

Create a new iterator function to simplify walking inodes in an XFS
filesystem.  This new iterator will replace the existing open-coded
walking that goes on in various places.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>

fs/xfs/Makefile

@@ -81,6 +81,7 @@ xfs-y				+= xfs_aops.o \
 				   xfs_iops.o \
 				   xfs_inode.o \
 				   xfs_itable.o \
+				   xfs_iwalk.o \
 				   xfs_message.o \
 				   xfs_mount.o \
 				   xfs_mru_cache.o \

fs/xfs/libxfs/xfs_ialloc_btree.c

@@ -562,6 +562,36 @@ xfs_inobt_max_size(
 					XFS_INODES_PER_CHUNK);
 }
 
+/* Read AGI and create inobt cursor. */
+int
+xfs_inobt_cur(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	xfs_agnumber_t		agno,
+	xfs_btnum_t		which,
+	struct xfs_btree_cur	**curpp,
+	struct xfs_buf		**agi_bpp)
+{
+	struct xfs_btree_cur	*cur;
+	int			error;
+
+	ASSERT(*agi_bpp == NULL);
+	ASSERT(*curpp == NULL);
+
+	error = xfs_ialloc_read_agi(mp, tp, agno, agi_bpp);
+	if (error)
+		return error;
+
+	cur = xfs_inobt_init_cursor(mp, tp, *agi_bpp, agno, which);
+	if (!cur) {
+		xfs_trans_brelse(tp, *agi_bpp);
+		*agi_bpp = NULL;
+		return -ENOMEM;
+	}
+	*curpp = cur;
+	return 0;
+}
+
 static int
 xfs_inobt_count_blocks(
 	struct xfs_mount	*mp,
@@ -570,15 +600,14 @@ xfs_inobt_count_blocks(
 	xfs_btnum_t		btnum,
 	xfs_extlen_t		*tree_blocks)
 {
-	struct xfs_buf		*agbp;
-	struct xfs_btree_cur	*cur;
+	struct xfs_buf		*agbp = NULL;
+	struct xfs_btree_cur	*cur = NULL;
 	int			error;
 
-	error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
+	error = xfs_inobt_cur(mp, tp, agno, btnum, &cur, &agbp);
 	if (error)
 		return error;
 
-	cur = xfs_inobt_init_cursor(mp, tp, agbp, agno, btnum);
 	error = xfs_btree_count_blocks(cur, tree_blocks);
 	xfs_btree_del_cursor(cur, error);
 	xfs_trans_brelse(tp, agbp);

fs/xfs/libxfs/xfs_ialloc_btree.h

@@ -64,5 +64,8 @@ int xfs_finobt_calc_reserves(struct xfs_mount *mp, struct xfs_trans *tp,
 		xfs_agnumber_t agno, xfs_extlen_t *ask, xfs_extlen_t *used);
 extern xfs_extlen_t xfs_iallocbt_calc_size(struct xfs_mount *mp,
 		unsigned long long len);
+int xfs_inobt_cur(struct xfs_mount *mp, struct xfs_trans *tp,
+		xfs_agnumber_t agno, xfs_btnum_t btnum,
+		struct xfs_btree_cur **curpp, struct xfs_buf **agi_bpp);
 
 #endif	/* __XFS_IALLOC_BTREE_H__ */

fs/xfs/xfs_itable.c

@@ -18,6 +18,7 @@
 #include "xfs_error.h"
 #include "xfs_icache.h"
 #include "xfs_health.h"
+#include "xfs_iwalk.h"
 
 /*
  * Return stat information for one inode.
@@ -160,7 +161,7 @@ xfs_bulkstat_one(
  * Loop over all clusters in a chunk for a given incore inode allocation btree
  * record.  Do a readahead if there are any allocated inodes in that cluster.
  */
-STATIC void
+void
 xfs_bulkstat_ichunk_ra(
 	struct xfs_mount		*mp,
 	xfs_agnumber_t			agno,
@@ -194,7 +195,7 @@ xfs_bulkstat_ichunk_ra(
  * are some left allocated, update the data for the pointed-to record as well as
  * return the count of grabbed inodes.
  */
-STATIC int
+int
 xfs_bulkstat_grab_ichunk(
 	struct xfs_btree_cur		*cur,	/* btree cursor */
 	xfs_agino_t			agino,	/* starting inode of chunk */

fs/xfs/xfs_itable.h

@@ -84,4 +84,12 @@ xfs_inumbers(
 	void			__user *buffer, /* buffer with inode info */
 	inumbers_fmt_pf		formatter);
 
+/* Temporarily needed while we refactor functions. */
+struct xfs_btree_cur;
+struct xfs_inobt_rec_incore;
+void xfs_bulkstat_ichunk_ra(struct xfs_mount *mp, xfs_agnumber_t agno,
+		struct xfs_inobt_rec_incore *irec);
+int xfs_bulkstat_grab_ichunk(struct xfs_btree_cur *cur, xfs_agino_t agino,
+		int *icount, struct xfs_inobt_rec_incore *irec);
+
 #endif	/* __XFS_ITABLE_H__ */

fs/xfs/xfs_iwalk.h

+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#ifndef __XFS_IWALK_H__
+#define __XFS_IWALK_H__
+
+/* Walk all inodes in the filesystem starting from @startino. */
+typedef int (*xfs_iwalk_fn)(struct xfs_mount *mp, struct xfs_trans *tp,
+			    xfs_ino_t ino, void *data);
+/* Return values for xfs_iwalk_fn. */
+#define XFS_IWALK_CONTINUE	(XFS_ITER_CONTINUE)
+#define XFS_IWALK_ABORT		(XFS_ITER_ABORT)
+
+int xfs_iwalk(struct xfs_mount *mp, struct xfs_trans *tp, xfs_ino_t startino,
+		xfs_iwalk_fn iwalk_fn, unsigned int inode_records, void *data);
+
+#endif /* __XFS_IWALK_H__ */

fs/xfs/xfs_trace.h

@@ -3517,6 +3517,46 @@ DEFINE_EVENT(xfs_inode_corrupt_class, name,	\
 DEFINE_INODE_CORRUPT_EVENT(xfs_inode_mark_sick);
 DEFINE_INODE_CORRUPT_EVENT(xfs_inode_mark_healthy);
 
+TRACE_EVENT(xfs_iwalk_ag,
+	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno,
+		 xfs_agino_t startino),
+	TP_ARGS(mp, agno, startino),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_agnumber_t, agno)
+		__field(xfs_agino_t, startino)
+	),
+	TP_fast_assign(
+		__entry->dev = mp->m_super->s_dev;
+		__entry->agno = agno;
+		__entry->startino = startino;
+	),
+	TP_printk("dev %d:%d agno %d startino %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->agno,
+		  __entry->startino)
+)
+
+TRACE_EVENT(xfs_iwalk_ag_rec,
+	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno,
+		 struct xfs_inobt_rec_incore *irec),
+	TP_ARGS(mp, agno, irec),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_agnumber_t, agno)
+		__field(xfs_agino_t, startino)
+		__field(uint64_t, freemask)
+	),
+	TP_fast_assign(
+		__entry->dev = mp->m_super->s_dev;
+		__entry->agno = agno;
+		__entry->startino = irec->ir_startino;
+		__entry->freemask = irec->ir_free;
+	),
+	TP_printk("dev %d:%d agno %d startino %u freemask 0x%llx",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->agno,
+		  __entry->startino, __entry->freemask)
+)
+
 #endif /* _TRACE_XFS_H */
 
 #undef TRACE_INCLUDE_PATH