After i/o: Remounting /dev/mmcblk0p1 causes hang.

[Eun]

By unmounting and remounting /dev/mmcblk0p1 my sdcard hangs. The wifi is active but no network connection can be established.

To get this issue do the following:

1. connect with telnet
2. write a file to the sdcard (take a photo with your camara or copy a file to it)
3. umount /mnt/sd
4. mount -t vfat --shortname=winnt /dev/mmcblk0p1 /mnt/sd The card hangs.

After a while the sdcard responses, and the mount command responses with mount: mounting /dev/mmcblk0p1 on /mnt/sd failed: Invalid argument

The syslog:[ 368.720000] FAT sec 7f8 sz 3c04 #2 rtdir 8000 csz 10 [ 454.870000] [ 454.870000] sw:0,m1:20170807: 3003000:0:0:0, 524, back2m1SDCardRead failed! (r s 1 2000,7:0,11c26603:101010) [ 506.180000] sw:0,m1:20170807: 3003000:0:0:0, 524, back2m1 [ 557.460000] sw:0,m1:20170807: 3003000:0:0:0, 524, back2m1 [ 608.750000] sw:0,m1:20170807: 3003000:0:0:0, 524, back2m1

I dono whether this is a problem of the card it self or the firmware.

I have the Transcend 16GB model.

[hillct]

I have the same model card and have been unable to reproduce this issue. I would certainly try reformatting the SD partition though the error is likely lower level than that. I'm guessing this is equally unhelpful but KeyAaic seems to recommend including the -w arg to force read/write when mounting the SD partition though of course read/write should be the default anyhow. Still it may be worth a shot since it's not entirely clear which argument is being considered inalid, so try

mount -w -t vfat --shortname=winnt /dev/mmcblk0p1 /mnt/sd

Also, since the SD partition is being mounted by two hosts (the device hosting the SD card slot, and the embedded linux system) it becomes important to sync often to assure FS integrity though I haven't seen sync errors cause a mount failure exhibiting the errors you've posted.