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magnusja
UsbFile#delete corrupts FAT16 files
Problem
After deleting a file, the other files get corrupted in certain cases. It looks similar to the issue https://github.com/magnusja/libaums/issues/144. I will attach memory images of the USB memory before and after deleting a file. (before_deleting_1st_file.img and after_deleting_1st_file.img. For attachment, each file was split by 10MB and zipped.)
I am using a USB memory that is under development by our company. Filesystem : FAT16 Memory capacity : 128 MB Sector size (BPB_BytsPerSec) : 4096 Bytes Number of sectors per cluster (BPB_SecPerClus) : 1
I am using libaums:0.7.4 and java-fs:0.1.4 in AndroidStudio. < build.gradle >
implementation 'com.github.mjdev:libaums:0.7.4'
implementation 'me.jahnen:java-fs:0.1.4'
I tried the latest code in the master branch of Nuix/Jnode-fs (commit : 72d3e97) and the problem reproduced yet.
Expected behavior
After deleting a file, the remaining files are not corrupted and can be read correctly.
Actual behavior
There are 8 files in the USB memory. When I delete any one of the 1st to 6th files, the 7th and 8th files get corrupted (FAT entries are set to 0). I will attach the difference between the FAT area before and after the deletion. (diff_before_and_after_deletion)
Stacktrace of Excpetion
When I try to read a corrupted file, I get the following exception:
IOException
free entry in chain at: 257
org.jnode.fs.jfat.FatChain$ChainIteratåor in next at line 717
org.jnode.fs.jfat.FatChain in read at liåne 362
org.jnode.fs.jfat.FatFile in read at line 92
com.github.magnusja.libaums.javafs.wrapper.fs.UsbFileWrapper in read at line 169
com.github.mjdev.libaums.fs.UsbFileInputStream in read at line 79
kotlin.io.ByteStreamsKt in copyTo at line 110
kotlin.io.ByteStreamsKt in copyTo$default at line 103
Code where problem occurs
I suspect that this can be solved by adding the following code in ByteBlockDevice#write: before arraycopy on line 97 of ByteBlockDevice.kt.
targetBlockDevice.read(devOffset, buffer)
buffer.flip()
or
targetBlockDevice.read(devOffset, buffer)
buffer.clear()
diff_before_and_after_deletion before_deleting_1st_file.img.aa.zip before_deleting_1st_file.img.ab.zip before_deleting_1st_file.img.ac.zip before_deleting_1st_file.img.ad.zip before_deleting_1st_file.img.ae.zip before_deleting_1st_file.img.af.zip before_deleting_1st_file.img.ag.zip before_deleting_1st_file.img.ah.zip before_deleting_1st_file.img.ai.zip before_deleting_1st_file.img.aj.zip before_deleting_1st_file.img.aj.zip before_deleting_1st_file.img.al.zip before_deleting_1st_file.img.am.zip after_deleting_1st_file.img.aa.zip after_deleting_1st_file.img.ab.zip after_deleting_1st_file.img.ac.zip after_deleting_1st_file.img.ad.zip after_deleting_1st_file.img.ae.zip after_deleting_1st_file.img.af.zip after_deleting_1st_file.img.ag.zip after_deleting_1st_file.img.ah.zip after_deleting_1st_file.img.ai.zip after_deleting_1st_file.img.aj.zip after_deleting_1st_file.img.ak.zip after_deleting_1st_file.img.al.zip after_deleting_1st_file.img.am.zip
Dear Mr. Magnus @magnusja Please let us know if you have any other information you need. It would be greatly appreciated if you could update libaums in the mavenCentral repository.
