From 8d5f321318c118139f164516f4119d9ec7f37af9 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Wed, 3 Jul 2024 14:22:12 -0700
Subject: [PATCH] xfs: refactor the allocation and freeing of incore inode fork
 btree roots

Refactor the code that allocates and freese the incore inode fork btree
roots.  This will help us disentangle some of the weird logic when we're
creating and tearing down inode-based btrees.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 libxfs/xfs_inode_fork.c | 57 ++++++++++++++++++++++++++++-------------
 libxfs/xfs_inode_fork.h |  3 +++
 2 files changed, 42 insertions(+), 18 deletions(-)

diff --git a/libxfs/xfs_inode_fork.c b/libxfs/xfs_inode_fork.c
index 89ae4e8af..519f29d77 100644
--- a/libxfs/xfs_inode_fork.c
+++ b/libxfs/xfs_inode_fork.c
@@ -209,9 +209,7 @@ xfs_iformat_btree(
 		return -EFSCORRUPTED;
 	}
 
-	ifp->if_broot_bytes = size;
-	ifp->if_broot = kmalloc(size,
-				GFP_KERNEL | __GFP_NOLOCKDEP | __GFP_NOFAIL);
+	xfs_iroot_alloc(ip, whichfork, size);
 	ASSERT(ifp->if_broot != NULL);
 	/*
 	 * Copy and convert from the on-disk structure
@@ -360,6 +358,33 @@ xfs_iformat_attr_fork(
 	return error;
 }
 
+/* Allocate a new incore ifork btree root. */
+void
+xfs_iroot_alloc(
+	struct xfs_inode	*ip,
+	int			whichfork,
+	size_t			bytes)
+{
+	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
+
+	ifp->if_broot = kmalloc(bytes,
+			GFP_KERNEL | __GFP_NOLOCKDEP | __GFP_NOFAIL);
+	ifp->if_broot_bytes = bytes;
+}
+
+/* Free all the memory and state associated with an incore ifork btree root. */
+void
+xfs_iroot_free(
+	struct xfs_inode	*ip,
+	int			whichfork)
+{
+	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
+
+	ifp->if_broot_bytes = 0;
+	kfree(ifp->if_broot);
+	ifp->if_broot = NULL;
+}
+
 /*
  * Reallocate the space for if_broot based on the number of records
  * being added or deleted as indicated in rec_diff.  Move the records
@@ -408,9 +433,7 @@ xfs_iroot_realloc(
 		 */
 		if (ifp->if_broot_bytes == 0) {
 			new_size = xfs_bmap_broot_space_calc(mp, rec_diff);
-			ifp->if_broot = kmalloc(new_size,
-						GFP_KERNEL | __GFP_NOFAIL);
-			ifp->if_broot_bytes = (int)new_size;
+			xfs_iroot_alloc(ip, whichfork, new_size);
 			return;
 		}
 
@@ -449,17 +472,16 @@ xfs_iroot_realloc(
 		new_size = xfs_bmap_broot_space_calc(mp, new_max);
 	else
 		new_size = 0;
-	if (new_size > 0) {
-		new_broot = kmalloc(new_size, GFP_KERNEL | __GFP_NOFAIL);
-		/*
-		 * First copy over the btree block header.
-		 */
-		memcpy(new_broot, ifp->if_broot,
-			xfs_bmbt_block_len(ip->i_mount));
-	} else {
-		new_broot = NULL;
+	if (new_size == 0) {
+		xfs_iroot_free(ip, whichfork);
+		return;
 	}
 
+	/* First copy over the btree block header. */
+	new_broot = kmalloc(new_size,
+			GFP_KERNEL | __GFP_NOLOCKDEP | __GFP_NOFAIL);
+	memcpy(new_broot, ifp->if_broot, xfs_bmbt_block_len(ip->i_mount));
+
 	/*
 	 * Only copy the records and pointers if there are any.
 	 */
@@ -483,9 +505,8 @@ xfs_iroot_realloc(
 	kfree(ifp->if_broot);
 	ifp->if_broot = new_broot;
 	ifp->if_broot_bytes = (int)new_size;
-	if (ifp->if_broot)
-		ASSERT(xfs_bmap_bmdr_space(ifp->if_broot) <=
-			xfs_inode_fork_size(ip, whichfork));
+	ASSERT(xfs_bmap_bmdr_space(ifp->if_broot) <=
+		xfs_inode_fork_size(ip, whichfork));
 	return;
 }
 
diff --git a/libxfs/xfs_inode_fork.h b/libxfs/xfs_inode_fork.h
index 2373d12fd..3f228a00b 100644
--- a/libxfs/xfs_inode_fork.h
+++ b/libxfs/xfs_inode_fork.h
@@ -170,6 +170,9 @@ void		xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *,
 void		xfs_idestroy_fork(struct xfs_ifork *ifp);
 void *		xfs_idata_realloc(struct xfs_inode *ip, int64_t byte_diff,
 				int whichfork);
+void		xfs_iroot_alloc(struct xfs_inode *ip, int whichfork,
+				size_t bytes);
+void		xfs_iroot_free(struct xfs_inode *ip, int whichfork);
 void		xfs_iroot_realloc(struct xfs_inode *, int, int);
 int		xfs_iread_extents(struct xfs_trans *, struct xfs_inode *, int);
 int		xfs_iextents_copy(struct xfs_inode *, struct xfs_bmbt_rec *,
-- 
2.50.1