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Re: [Qemu-block] [PATCH 0/2] Fix werror=enospc for qcow2 on iscsi
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-block] [PATCH 0/2] Fix werror=enospc for qcow2 on iscsi |
Date: |
Thu, 22 Oct 2015 10:45:06 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 22/10/2015 10:17, Fam Zheng wrote:
> When qcow2 is created on iscsi target with a virtual size greater than
> physical
> capacity of the LUN, over time it's possible that guest fills too much data
> and
> at that point, new clusters in qcow2 will be allocated beyond the end of disk.
>
> werror=enospc is useful for that purpose to allocate more data for the guest,
> except in this case, unlike a host file system, iscsi returns -EIO instead of
> -ENOSPC, which makes it hard to detect and report proper error.
>
> Fix this by improving iscsi error handling code to return meaningful error
> codes (-ERANGE here), then further translate it to -ENOSPC in qcow2.
FWIW, Linux uses ENOSPC if it detects out of range LBAs:
if (iocb->ki_pos >= size)
return -ENOSPC;
so I think it's okay to convert LBA_OUT_OF_RANGE to ENOSPC directly and
avoid patch 2.
Paolo
[Qemu-block] [PATCH 2/2] qcow2: Translate -ERANGE to -ENOSPC, Fam Zheng, 2015/10/22
Re: [Qemu-block] [PATCH 0/2] Fix werror=enospc for qcow2 on iscsi, Peter Lieven, 2015/10/22
Re: [Qemu-block] [PATCH 0/2] Fix werror=enospc for qcow2 on iscsi,
Paolo Bonzini <=