Re: dead or dying SDXC card fsck's OK but mount hangs indefinitely

On Sat, Mar 31, 2018 at 03:50:03PM -0600, Chris Murphy wrote:

This is perhaps a novelty problem report. And it's also a throw away
card data wise, and is a $12 Samsung EVO+ SDXC card used in an Intel
NUC.

It contains FAT, ext4, and Btrfs file systems. They can all be fsck'd,
but none can be mounted. Even if it use blockdev --setro on the entire
mmc device and then mount -o ro it still fails. Kinda weird huh?

[69107.488123] mmc0: Card stuck in programming state! mmcblk0 card_busy_detect
[69107.539128] mmc0: Tuning timeout, falling back to fixed sampling clock

The corrupt 10 was fixed with a scrub months ago, and I never reset
the counter so that's not a current corruption. The most recent scrub
was maybe a week ago. And even offline scrub works. So literally every
single block related to this Btrfs file system is readable, and yet
it's not mountable? Very weird.

Basically the card is in some sort of state that the kernel code is
not going to ever second guess. So there's no further error or reset
attempt.

As the SD card is tiny compared to any hard disks (be they spinning or
solid), I'd dd it as an image as the first step.

This in general is a wise step for any kind of recovery, but in your case
it's especially easy.  It also lets you separate hardware issues from
filesystem corruption.


Meow!
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