[PATCH 5/7] xfs: add support for inode btree staging cursors

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

Add support for btree staging cursors for the inode btrees.  This
is needed both for online repair and also to convert xfs_repair to use
btree bulk loading.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_ialloc_btree.c |   80 +++++++++++++++++++++++++++++++++-----
 fs/xfs/libxfs/xfs_ialloc_btree.h |    6 +++
 2 files changed, 75 insertions(+), 11 deletions(-)


diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
index e0e8570af023..d7cf74a68578 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.c
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
@@ -400,32 +400,27 @@ static const struct xfs_btree_ops xfs_finobt_ops = {
 };
 
 /*
- * Allocate a new inode btree cursor.
+ * Initialize a new inode btree cursor.
  */
-struct xfs_btree_cur *				/* new inode btree cursor */
-xfs_inobt_init_cursor(
+static struct xfs_btree_cur *
+xfs_inobt_init_common(
 	struct xfs_mount	*mp,		/* file system mount point */
 	struct xfs_trans	*tp,		/* transaction pointer */
-	struct xfs_buf		*agbp,		/* buffer for agi structure */
 	xfs_agnumber_t		agno,		/* allocation group number */
 	xfs_btnum_t		btnum)		/* ialloc or free ino btree */
 {
-	struct xfs_agi		*agi = agbp->b_addr;
 	struct xfs_btree_cur	*cur;
 
 	cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
-
 	cur->bc_tp = tp;
 	cur->bc_mp = mp;
 	cur->bc_btnum = btnum;
 	if (btnum == XFS_BTNUM_INO) {
-		cur->bc_nlevels = be32_to_cpu(agi->agi_level);
-		cur->bc_ops = &xfs_inobt_ops;
 		cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_ibt_2);
+		cur->bc_ops = &xfs_inobt_ops;
 	} else {
-		cur->bc_nlevels = be32_to_cpu(agi->agi_free_level);
-		cur->bc_ops = &xfs_finobt_ops;
 		cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_fibt_2);
+		cur->bc_ops = &xfs_finobt_ops;
 	}
 
 	cur->bc_blocklog = mp->m_sb.sb_blocklog;
@@ -433,12 +428,75 @@ xfs_inobt_init_cursor(
 	if (xfs_sb_version_hascrc(&mp->m_sb))
 		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
 
-	cur->bc_ag.agbp = agbp;
 	cur->bc_ag.agno = agno;
+	return cur;
+}
 
+/* Create an inode btree cursor. */
+struct xfs_btree_cur *
+xfs_inobt_init_cursor(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	struct xfs_buf		*agbp,
+	xfs_agnumber_t		agno,
+	xfs_btnum_t		btnum)
+{
+	struct xfs_btree_cur	*cur;
+	struct xfs_agi		*agi = agbp->b_addr;
+
+	cur = xfs_inobt_init_common(mp, tp, agno, btnum);
+	if (btnum == XFS_BTNUM_INO)
+		cur->bc_nlevels = be32_to_cpu(agi->agi_level);
+	else
+		cur->bc_nlevels = be32_to_cpu(agi->agi_free_level);
+	cur->bc_ag.agbp = agbp;
 	return cur;
 }
 
+/* Create an inode btree cursor with a fake root for staging. */
+struct xfs_btree_cur *
+xfs_inobt_stage_cursor(
+	struct xfs_mount	*mp,
+	struct xbtree_afakeroot	*afake,
+	xfs_agnumber_t		agno,
+	xfs_btnum_t		btnum)
+{
+	struct xfs_btree_cur	*cur;
+
+	cur = xfs_inobt_init_common(mp, NULL, agno, btnum);
+	xfs_btree_stage_afakeroot(cur, afake, NULL);
+	return cur;
+}
+
+/*
+ * Install a new inobt btree root.  Caller is responsible for invalidating
+ * and freeing the old btree blocks.
+ */
+void
+xfs_inobt_commit_staged_btree(
+	struct xfs_btree_cur	*cur,
+	struct xfs_trans	*tp,
+	struct xfs_buf		*agbp)
+{
+	struct xfs_agi		*agi = agbp->b_addr;
+	struct xbtree_afakeroot	*afake = cur->bc_ag.afake;
+
+	ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
+
+	if (cur->bc_btnum == XFS_BTNUM_INO) {
+		agi->agi_root = cpu_to_be32(afake->af_root);
+		agi->agi_level = cpu_to_be32(afake->af_levels);
+		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_ROOT | XFS_AGI_LEVEL);
+		xfs_btree_commit_afakeroot(cur, tp, agbp, &xfs_inobt_ops);
+	} else {
+		agi->agi_free_root = cpu_to_be32(afake->af_root);
+		agi->agi_free_level = cpu_to_be32(afake->af_levels);
+		xfs_ialloc_log_agi(tp, agbp, XFS_AGI_FREE_ROOT |
+					     XFS_AGI_FREE_LEVEL);
+		xfs_btree_commit_afakeroot(cur, tp, agbp, &xfs_finobt_ops);
+	}
+}
+
 /*
  * Calculate number of records in an inobt btree block.
  */
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.h b/fs/xfs/libxfs/xfs_ialloc_btree.h
index 951305ecaae1..35bbd978c272 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.h
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.h
@@ -48,6 +48,9 @@ struct xfs_mount;
 extern struct xfs_btree_cur *xfs_inobt_init_cursor(struct xfs_mount *,
 		struct xfs_trans *, struct xfs_buf *, xfs_agnumber_t,
 		xfs_btnum_t);
+struct xfs_btree_cur *xfs_inobt_stage_cursor(struct xfs_mount *mp,
+		struct xbtree_afakeroot *afake, xfs_agnumber_t agno,
+		xfs_btnum_t btnum);
 extern int xfs_inobt_maxrecs(struct xfs_mount *, int, int);
 
 /* ir_holemask to inode allocation bitmap conversion */
@@ -68,4 +71,7 @@ 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);
 
+void xfs_inobt_commit_staged_btree(struct xfs_btree_cur *cur,
+		struct xfs_trans *tp, struct xfs_buf *agbp);
+
 #endif	/* __XFS_IALLOC_BTREE_H__ */