diff --git a/kernel/fs.c b/kernel/fs.c
index 454d52b..da9bcca 100644
--- a/kernel/fs.c
+++ b/kernel/fs.c
@@ -495,8 +495,10 @@ writei(struct inode *ip, int user_src, uint64 src, uint off, uint n)
   for(tot=0; tot<n; tot+=m, off+=m, src+=m){
     bp = bread(ip->dev, bmap(ip, off/BSIZE));
     m = min(n - tot, BSIZE - off%BSIZE);
-    if(either_copyin(bp->data + (off % BSIZE), user_src, src, m) == -1)
+    if(either_copyin(bp->data + (off % BSIZE), user_src, src, m) == -1) {
+      brelse(bp);
       break;
+    }
     log_write(bp);
     brelse(bp);
   }