Fixed race condition

Author: tinchoz49

index.js

@@ -152,7 +152,7 @@ WriteRequest.prototype.onwrite = function (err, e) {
   }
 
   if (!err) {
-    this.file.updateSize(e.currentTarget.length)
+    this.file.updateSize(e.currentTarget.length, this.truncating)
   }
 
   if (this.truncating) {
@@ -166,7 +166,6 @@ WriteRequest.prototype.onwrite = function (err, e) {
 
 WriteRequest.prototype.truncate = function () {
   this.truncating = true
-  this.file.truncate()
   this.writer.truncate(this.req.offset)
 }
 
@@ -249,7 +248,10 @@ ReadRequest.prototype.onread = function (err, buf) {
   const req = this.req
 
   if (err && this.retry) {
-    this.retry = false
+    if (err.code !== 0) {
+      this.retry = false
+    }
+
     if (this.lock(this)) {
       this.file.clearFile()
       this.run(req)
@@ -286,41 +288,35 @@ class EntryFile {
     this._lock = mutexify()
     this._file = null
     this._size = 0
-    this._truncated = false
   }
 
   get size () {
     return this._size
   }
 
-  updateSize (size) {
-    if (!this._truncated) {
+  updateSize (size, truncating) {
+    if (truncating || size > this._size) {
       this._size = size
     }
 
     this.clearFile()
   }
 
-  truncate () {
-    this._truncated = true
-  }
-
   clearFile () {
     this._file = null
   }
 
   get (cb) {
-    if (this._file && !this._truncated) {
+    if (this._file) {
       return cb(null, this._file)
     }
 
     this._lock(release => {
-      if (this._file && !this._truncated) {
+      if (this._file) {
         return release(cb, null, this._file)
       }
 
       this._entry.file(file => {
-        this._truncated = false
         this._file = file
         this._size = file.size
         release(cb, null, file)
@@ -329,10 +325,6 @@ class EntryFile {
   }
 
   getWritableFile (cb) {
-    if (!this._truncated) {
-      return cb(null, this)
-    }
-
-    this.get(cb)
+    return cb(null, this)
   }
 }

test.js

@@ -1,3 +1,4 @@
+const { promisify } = require('util')
 const test = require('tape')
 const randomAccessTest = require('random-access-test')
 const racf = require('./')
@@ -14,20 +15,8 @@ test('write/read concurrent requests', async t => {
   const st = storage('random')
 
   const rand = (min, max) => Math.floor(Math.random() * max) + min
-
-  const read = (...args) => new Promise((resolve, reject) => {
-    st.read(...args, (err) => {
-      if (err) return reject(err)
-      resolve()
-    })
-  })
-
-  const write = (...args) => new Promise((resolve, reject) => {
-    st.write(...args, (err) => {
-      if (err) return reject(err)
-      resolve()
-    })
-  })
+  const read = promisify(st.read.bind(st))
+  const write = promisify(st.write.bind(st))
 
   try {
     await new Promise(resolve => st.open(() => resolve()))
@@ -55,3 +44,24 @@ test('write/read concurrent requests', async t => {
     t.end(err)
   }
 })
+
+test('write concurrent requests over the same offset different size', async t => {
+  const st = storage('random')
+
+  const write = promisify(st.write.bind(st))
+
+  try {
+    await new Promise(resolve => st.open(() => resolve()))
+
+    await Promise.all([
+      write(0, Buffer.alloc(10)),
+      write(0, Buffer.alloc(1)),
+      write(0, Buffer.alloc(5))
+    ])
+
+    t.pass('should write multiple requests over the same offset different size')
+    t.end()
+  } catch (err) {
+    t.end(err)
+  }
+})