diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 6e448f50cef45cd9b9e4ea75f280c76b41a27e89..4dd3238161cf3fa2af89efda39247267c9bea581 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -586,6 +586,13 @@ xfs_alloc_fixup_trees(
 		nfbno2 = rbno + rlen;
 		nflen2 = (fbno + flen) - nfbno2;
 	}
+
+	/*
+	 * Record the potential maximum free length in advance.
+	 */
+	if (nfbno1 != NULLAGBLOCK || nfbno2 != NULLAGBLOCK)
+		cnt_cur->bc_ag.bc_free_longest = XFS_EXTLEN_MAX(nflen1, nflen2);
+
 	/*
 	 * Delete the entry from the by-size btree.
 	 */
@@ -2019,6 +2026,13 @@ xfs_free_ag_extent(
 	 * Now allocate and initialize a cursor for the by-size tree.
 	 */
 	cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, pag, XFS_BTNUM_CNT);
+	/*
+	 * Record the potential maximum free length in advance.
+	 */
+	if (haveleft)
+		cnt_cur->bc_ag.bc_free_longest = ltlen;
+	if (haveright)
+		cnt_cur->bc_ag.bc_free_longest = gtlen;
 	/*
 	 * Have both left and right contiguous neighbors.
 	 * Merge all three into a single free block.
diff --git a/fs/xfs/libxfs/xfs_alloc_btree.c b/fs/xfs/libxfs/xfs_alloc_btree.c
index c65228efed4aeca98b645aefa01dd70892601168..d2c7a217a74b15a41ca2f8ebd4746563280c7304 100644
--- a/fs/xfs/libxfs/xfs_alloc_btree.c
+++ b/fs/xfs/libxfs/xfs_alloc_btree.c
@@ -146,7 +146,14 @@ xfs_allocbt_update_lastrec(
 			rrp = XFS_ALLOC_REC_ADDR(cur->bc_mp, block, numrecs);
 			len = rrp->ar_blockcount;
 		} else {
-			len = 0;
+			/*
+			 * Update in advance to prevent file creation failure
+			 * for concurrent processes even though there is no
+			 * numrec currently.
+			 * And there's no need to worry as the value that no
+			 * less than bc_free_longest will be inserted later.
+			 */
+			len = cpu_to_be32(cur->bc_ag.bc_free_longest);
 		}
 
 		break;
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index 4d68a58be160cf86452d4fbb21eaf1b2de8fe6a3..bf63bbcd49143619b83efbaefd02bbf534906bb0 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -218,6 +218,7 @@ union xfs_btree_irec {
 /* Per-AG btree information. */
 struct xfs_btree_cur_ag {
 	struct xfs_perag		*pag;
+	xfs_extlen_t			bc_free_longest; /* the potential longest free extent */
 	union {
 		struct xfs_buf		*agbp;
 		struct xbtree_afakeroot	*afake;	/* for staging cursor */