xfs: decouple xfs_trans_alloc_empty from xfs_trans_alloc

[ Upstream commit 83a80e9 ]

xfs_trans_alloc_empty only shares the very basic transaction structure
allocation and initialization with xfs_trans_alloc.

Split out a new __xfs_trans_alloc helper for that and otherwise decouple
xfs_trans_alloc_empty from xfs_trans_alloc.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Stable-dep-of: d284551 ("xfs: fully decouple XFS_IBULK* flags from XFS_IWALK* flags")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Christoph Hellwig

fs/xfs/xfs_trans.c

@@ -241,6 +241,28 @@ xfs_trans_reserve(
 	return error;
 }
 
+static struct xfs_trans *
+__xfs_trans_alloc(
+	struct xfs_mount	*mp,
+	uint			flags)
+{
+	struct xfs_trans	*tp;
+
+	ASSERT(!(flags & XFS_TRANS_RES_FDBLKS) || xfs_has_lazysbcount(mp));
+
+	tp = kmem_cache_zalloc(xfs_trans_cache, GFP_KERNEL | __GFP_NOFAIL);
+	if (!(flags & XFS_TRANS_NO_WRITECOUNT))
+		sb_start_intwrite(mp->m_super);
+	xfs_trans_set_context(tp);
+	tp->t_flags = flags;
+	tp->t_mountp = mp;
+	INIT_LIST_HEAD(&tp->t_items);
+	INIT_LIST_HEAD(&tp->t_busy);
+	INIT_LIST_HEAD(&tp->t_dfops);
+	tp->t_highest_agno = NULLAGNUMBER;
+	return tp;
+}
+
 int
 xfs_trans_alloc(
 	struct xfs_mount	*mp,
@@ -254,33 +276,16 @@ xfs_trans_alloc(
 	bool			want_retry = true;
 	int			error;
 
+	ASSERT(resp->tr_logres > 0);
+
 	/*
 	 * Allocate the handle before we do our freeze accounting and setting up
 	 * GFP_NOFS allocation context so that we avoid lockdep false positives
 	 * by doing GFP_KERNEL allocations inside sb_start_intwrite().
 	 */
 retry:
-	tp = kmem_cache_zalloc(xfs_trans_cache, GFP_KERNEL | __GFP_NOFAIL);
-	if (!(flags & XFS_TRANS_NO_WRITECOUNT))
-		sb_start_intwrite(mp->m_super);
-	xfs_trans_set_context(tp);
-
-	/*
-	 * Zero-reservation ("empty") transactions can't modify anything, so
-	 * they're allowed to run while we're frozen.
-	 */
-	WARN_ON(resp->tr_logres > 0 &&
-		mp->m_super->s_writers.frozen == SB_FREEZE_COMPLETE);
-	ASSERT(!(flags & XFS_TRANS_RES_FDBLKS) ||
-	       xfs_has_lazysbcount(mp));
-
-	tp->t_flags = flags;
-	tp->t_mountp = mp;
-	INIT_LIST_HEAD(&tp->t_items);
-	INIT_LIST_HEAD(&tp->t_busy);
-	INIT_LIST_HEAD(&tp->t_dfops);
-	tp->t_highest_agno = NULLAGNUMBER;
-
+	WARN_ON(mp->m_super->s_writers.frozen == SB_FREEZE_COMPLETE);
+	tp = __xfs_trans_alloc(mp, flags);
 	error = xfs_trans_reserve(tp, resp, blocks, rtextents);
 	if (error == -ENOSPC && want_retry) {
 		xfs_trans_cancel(tp);
@@ -329,9 +334,8 @@ xfs_trans_alloc_empty(
 	struct xfs_mount		*mp,
 	struct xfs_trans		**tpp)
 {
-	struct xfs_trans_res		resv = {0};
-
-	return xfs_trans_alloc(mp, &resv, 0, 0, XFS_TRANS_NO_WRITECOUNT, tpp);
+	*tpp = __xfs_trans_alloc(mp, XFS_TRANS_NO_WRITECOUNT);
+	return 0;
 }
 
 /*