linux-ext4 - Re: ext4: failed to convert unwritten extents (6.12.31 regression)

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Message-ID:
 <BN9PR18MB4219710FC26F8A610F53AF569812A@BN9PR18MB4219.namprd18.prod.outlook.com>
Date: Mon, 22 Sep 2025 14:00:20 +0000
From: Andrea Biardi <Andrea.Biardi@...visolutions.com>
To: Theodore Ts'o <tytso@....edu>
CC: linux-ext4 <linux-ext4@...r.kernel.org>
Subject: Re: ext4: failed to convert unwritten extents (6.12.31 regression)

On 22-Sep-2025,  "Theodore Ts'o" <tytso@....edu> wrote:

> > [  174.903010] I/O error, dev vda, sector 167922 op 0x1:(WRITE) flags 0x0 phys_seg 2 prio class 0
> > [  174.903023] I/O error, dev vda, sector 167938 op 0x1:(WRITE) flags 0x4000 phys_seg 254 prio class 0
> > [  174.903027] I/O error, dev vda, sector 169970 op 0x1:(WRITE) flags 0x0 phys_seg 2 prio class 0
> > [  174.903031] EXT4-fs warning (device vda1): ext4_end_bio:353: I/O error 10 writing to inode 16 starting block 84985)
>
> The failure is coming from the block device, which in your case, is
> the virtio device.  The only causes for this are:
> 1)  An underlying hardware failure
> 2)  A bug in the block virtio device
> 3)  A bug in the VMM (I assume qemu in your case).

Thank you for the quick response!

You do have a point there, the first reported problem is effectively a write failure on vda.
I tried with virtio-scsi, and can't reproduce the bug. I will try with a newer version of qemu first, and then look into virtio-blk.

Cheers,
Andrea.