[PATCH 02/14] xfs: refactor the allocation and freeing of incore inode fork btree roots

["Darrick J. Wong" <djwong@xxxxxxxxxx>]

From: Darrick J. Wong <djwong@xxxxxxxxxx>

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@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_inode_fork.c |   53 ++++++++++++++++++++++++++++------------
 fs/xfs/libxfs/xfs_inode_fork.h |    3 ++
 2 files changed, 40 insertions(+), 16 deletions(-)


diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index 9d53df7ce49d..0f220f100069 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -207,8 +207,7 @@ xfs_iformat_btree(
 		return -EFSCORRUPTED;
 	}
 
-	ifp->if_broot_bytes = size;
-	ifp->if_broot = kmem_alloc(size, KM_NOFS);
+	xfs_iroot_alloc(ip, whichfork, size);
 	ASSERT(ifp->if_broot != NULL);
 	/*
 	 * Copy and convert from the on-disk structure
@@ -344,6 +343,32 @@ 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 = kmem_alloc(bytes, KM_NOFS);
+	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;
+	kmem_free(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
@@ -392,8 +417,7 @@ xfs_iroot_realloc(
 		 */
 		if (ifp->if_broot_bytes == 0) {
 			new_size = xfs_bmap_broot_space_calc(mp, rec_diff);
-			ifp->if_broot = kmem_alloc(new_size, KM_NOFS);
-			ifp->if_broot_bytes = (int)new_size;
+			xfs_iroot_alloc(ip, whichfork, new_size);
 			return;
 		}
 
@@ -432,17 +456,15 @@ xfs_iroot_realloc(
 		new_size = xfs_bmap_broot_space_calc(mp, new_max);
 	else
 		new_size = 0;
-	if (new_size > 0) {
-		new_broot = kmem_alloc(new_size, KM_NOFS);
-		/*
-		 * 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 = kmem_alloc(new_size, KM_NOFS);
+	memcpy(new_broot, ifp->if_broot, xfs_bmbt_block_len(ip->i_mount));
+
 	/*
 	 * Only copy the records and pointers if there are any.
 	 */
@@ -466,9 +488,8 @@ xfs_iroot_realloc(
 	kmem_free(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/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index c201d8ad5957..f4379e2df616 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -171,6 +171,9 @@ 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 *,