diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index b901eedf3bb81bf41a9b9f223c670f7e293e1ab2..95bfe89651add0e260964d756fb295f9a9872d04 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -543,6 +543,13 @@ 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_free_longest = max_t(xfs_extlen_t, nflen1, nflen2);
+
 	/*
 	 * Delete the entry from the by-size btree.
 	 */
@@ -2039,6 +2046,13 @@ xfs_free_ag_extent(
 	 * Now allocate and initialize a cursor for the by-size tree.
 	 */
 	cnt_cur = xfs_allocbt_init_cursor(mp, tp, agbp, agno, XFS_BTNUM_CNT);
+	/*
+	 * Record the potential maximum free length in advance.
+	 */
+	if (haveleft)
+		cnt_cur->bc_free_longest = ltlen;
+	if (haveright)
+		cnt_cur->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 613a1743fdd596b152579d9eaaadfe1e7791dcfe..8282a171131e811f71e872997ef2701e164b2545 100644
--- a/fs/xfs/libxfs/xfs_alloc_btree.c
+++ b/fs/xfs/libxfs/xfs_alloc_btree.c
@@ -141,13 +141,20 @@ xfs_allocbt_update_lastrec(
 			return;
 		ASSERT(ptr == numrecs + 1);
 
+		/*
+		 * 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 not
+		 * less than bc_free_longest will be inserted later.
+		 */
+		len = cpu_to_be32(cur->bc_free_longest);
 		if (numrecs) {
 			xfs_alloc_rec_t *rrp;
 
 			rrp = XFS_ALLOC_REC_ADDR(cur->bc_mp, block, numrecs);
-			len = rrp->ar_blockcount;
-		} else {
-			len = 0;
+			len = cpu_to_be32(max_t(xfs_extlen_t, cur->bc_free_longest,
+						be32_to_cpu(rrp->ar_blockcount)));
 		}
 
 		break;
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index d172046ae833fca8cb02c6163ff47d048e6c4eba..1d89b897c056d170d880ca551345ce9d5de0fac4 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -235,6 +235,7 @@ typedef struct xfs_btree_cur
 		struct xfs_btree_cur_ag	bc_ag;
 		struct xfs_btree_cur_ino bc_ino;
 	};
+	xfs_extlen_t	bc_free_longest;	/* the actual longest free extent */
 } xfs_btree_cur_t;
 
 /* cursor flags */