-----Oorspronkelijk bericht----- Van: Ruud Commandeur Verzonden: vrijdag 17 januari 2014 16:50 Aan: 'Detlev Zundel' CC: U-Boot list Onderwerp: RE: [U-Boot] Fat write problem
-----Oorspronkelijk bericht----- Van: Detlev Zundel [mailto:dzu@denx.de] Verzonden: vrijdag 17 januari 2014 15:59 Aan: Ruud Commandeur CC: U-Boot list Onderwerp: Re: [U-Boot] Fat write problem
Hi Ruud,
This week I decided to do some further research and testing
regarding
this problem. With the image I had from the previous time, I could immediately reproduce it and by adding more and more debug prints, I tried to find the
cause. Sofar,
I have not succeeded in this yet.
However: later on I started testing with a freshly
formatted drive (32
MB FAT partition) and kept repeating the fatwrite command:
fatwrite mmc 0:1 42000000 test-x 200
where x runs from 1, 2,3 and further. And this way I could
reproduce it
quite easily. Writing always fails for the 32nd file. This is with the partition formatted with a 512 byte sector size and a cluster size of 4. If the cluster size is
1 (formatted
by Windows), it already fails at the 8th file.
If I create a subdirectory (from Linux) with already 24
files in it, I
can still write 29 files and it fails at number 30. Also, if earlier files were
deleted from the
root-directory, they still count in the total number of files here.
If I take out the card where u-boot fails to write new
files, I can
still add new files from my PC with Linux or Windows.
I tested with both long and short filenames (same result), VFAT is enabled.
I hope this gives you all some more information about this
problem and
perhaps it is even a known problem (limited number of files in the root
directory?). I know
it is voor FAT16, but that was 512 entries if I am correct.
Thanks for the extensive research into this problem. For people to help, I think the barrier of reproducing the problem is "somewhat high", so it occurred to me if you can help setup a very
easy test for
people to work on. Would you be able to generate a small image that one can dd to a mmc card and then immediately provoke the error? If you don't have any hosting space, as a last resort I'd be fine
for you to
put it on our wiki [1].
Hi Detlev,
Thanks for your response. Finally I get some ;-)
I can look for creating some image, but I don't think it is that hard to reproduce (now I think to know what causes it). Either use 32 times the fatwrite command (using the cmd history and increment the x-nr each time) or just copy up to 31 files to the root of the FAT partition by using the host machine and place the SD-card back on the targe device running u-boot.
Hope this makes it easy enough, otherwise I will be glad to hear from you.
N.B. All this was with a FAT16 partition. If I use FAT32, I have no such problem! At least not for 45 files up till now...
Regards,
Ruud
Hi Detlev (and others),
Just to be absolutely sure, I did a new attempt.
Created 32 MB FAT16 (type 06) partition with fdisk on my SD-Card (1st parttion). Formatted as FAT16, 4 sectors per cluster:
"sudo mkfs.vfat -v -n IPCAN -F 16 -s 4 /dev/sdf1"
Created 30 files on this mounted partition:
"for i in {1..30}; do touch /media/IPCAN/test-$i; done"
Plugged the SD-card into my EVK running u-boot and started fatwrite testing:
fatwrite mmc 0:1 42000000 test-31 writing test-31 0 bytes written CLB IP-CAN U-Boot > fatwrite mmc 0:1 42000000 test-32 writing test-32 MMC: block number 0x1002006 exceeds max(0x746000) error: overflow occurs error: overflow occurs ... ...
And the error is there and will remain there for any further attempts. So it doesn't matter how and where the files were created, and what size the files are, adding files >= 32 jut fails for FAT16.
Note that also "test-16" is missing when doing a "fatls mmc 0:1". The file can be read though when doing a fatload for this file. This is probably some other problem, but could be related.
For now, I will continue using FAT32. If any problems would arise there I will post them.
Regards,
Ruud
Cheers Detlev
[1] http://www.denx.de/wiki/view/U-Boot/TooBigPatches
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