open failed: EBUSY (Device or resource busy)

Question

I have a strange error in my App.

In my app it is possible to download a zipFile, read the content as what it is and also delete it. Its doesn't matter what exactly it is.

Problem: Only on the Motorola Xoom (version 4.0.4) I can download the file, unzip it, I can read the data and I can delete everything. But if I try to Download the file again and while it unzip the file and copy the files to SD-Card it crashes with the error EBUSY (Device or resource busy).

1. Why is it working only the first time?
2. What means that error?
3. Why i get this error only on the Xoom?

I can't find any solution for that. On all other devices it works fine, no errors or problems.

LogCat:

07-18 12:27:46.774: E/PrepareMagTask(10057): IOException
07-18 12:27:46.774: E/PrepareMagTask(10057): java.io.FileNotFoundException: /mnt/sdcard/Android/data/com.xxxxxx.android/files/content/23760/emag.db: open failed: EBUSY (Device or resource busy)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at libcore.io.IoBridge.open(IoBridge.java:406)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at java.io.FileOutputStream.<init>(FileOutputStream.java:88)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at java.io.FileOutputStream.<init>(FileOutputStream.java:73)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at com.xxxxx.android.util.io.ZipHelper.uncompressEntry(ZipHelper.java:35)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at com.xxxxx.android.task.PrepareMagTask.doInBackground(PrepareMagTask.java:271)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at com.xxxxx.android.task.PrepareMagTask.doInBackground(PrepareMagTask.java:1)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at android.os.AsyncTask$2.call(AsyncTask.java:264)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at java.lang.Thread.run(Thread.java:856)
07-18 12:27:46.774: E/PrepareMagTask(10057): Caused by: libcore.io.ErrnoException: open failed: EBUSY (Device or resource busy)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at libcore.io.Posix.open(Native Method)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
07-18 12:27:46.774: E/PrepareMagTask(10057):    at libcore.io.IoBridge.open(IoBridge.java:390)
07-18 12:27:46.774: E/PrepareMagTask(10057):    ... 11 more

It crashes at line 35 in my ZipHelper class:

FileHelper.copy(zipFile.getInputStream(entry), new FileOutputStream(outputFile), modify);

getInputStream(entry) ... and I really dont know why?

Is there a method to wait for the device or recourse, when it is busy? This is happened every time I try to unzip the file, the app tries it 5 time (Downloading -> Unzip) and it crashes every time.

EDIT: We found out, its not only the Xoom. We also have the error with the Asus Transformer with the version 4.0.4

Answer 1

I have a big Answer!! The Problem comes from the Android System or/and the FAT32 system. I can not explain how the system gets the error, it has something to do with deleting files and the FAT32 System.

But the solution is really easy: Before you delete a Directory or File: rename it!

Code to rename:

final File to = new File(file.getAbsolutePath() + System.currentTimeMillis());
file.renameTo(to);
to.delete();

That's it, if you rename the folder or file before you delete it, there is no chance for the system to try to open an existing file again or an open file which you want to save again (or something like this).

Answer 2

This issue may be cause by

• two or more process reference the same file

• file was deleted,but the reference not be killed

However,deleted it,only one reference was killed,or one or more process reference this file also

you can step by step:

before you delete the file you should

• adb shell lsof | grep "com.xxxxxx.android"

The file you have been opened,and which process reference the file which you opened. also,this command ,show us the process id

than,

• adb shell ls -al /proc/%d/fd

Surprise waiting for you, O(∩_∩)O

good luck!