Re: [Qemu-devel] [PATCH for-2.12] block: handle invalid lseek returns gracefully

[Eric Blake <eblake@redhat.com>]

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On 04/02/2018 11:37 PM, Jeff Cody wrote:
> In commit 223a23c198787328ae75bc65d84edf5fde33c0b6, we implemented a
> workaround in the gluster driver to handle invalid values returned for
> SEEK_DATA or SEEK_HOLE.
> 
> In some instances, these same invalid values can be seen in the posix
> file handler as well - for example, it has been reported on FUSE gluster
> mounts.

Yuck - that should be reported to the FUSE and gluster folks, as it does
not scale to have everyone else work around their bug.  But in the
meantime, working around it here is acceptable.

> 
> Calling assert() for these invalid values is overly harsh; we can safely
> return -EIO and allow this case to be treated as a "learned nothing"
> case (e.g., D4 / H4, as commented in the code).
> 
> This patch does the same thing that 223a23c198787 did for gluster.c,
> except in file-posix.c
> 
> Signed-off-by: Jeff Cody <jcody@redhat.com>
> ---
>  block/file-posix.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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