Re: NFS/localio: fix nfs_local_dio_misaligned tracepoint

[Mike Snitzer <snitzer@kernel.org>]

On Tue, Jul 21, 2026 at 09:56:33AM -0400, Anna Schumaker wrote:
> Hi Mike,
> 
> On Wed, Jul 8, 2026, at 5:36 PM, Mike Snitzer wrote:
> > The intended focus of nfs_local_iters_setup_dio()'s call to
> > trace_nfs_local_dio_misaligned() is on the middle segment being
> > misaligned, yet the @offset passed in was local_dio->start_len.
> > It would appear this was a cut-n-paste bug from the preceding
> > nfs_local_iter_setup() call that passes local_dio->start_len.
> >
> > Fix this by passing the @offset as local_dio->middle_offset and
> > calculate the start segment's offset rather than assume.
> >
> > Example traces, before this fix:
> >
> >    python3-32744   [006] .l... 132946.352360:
> >    nfs_local_dio_write: fileid=00:33:1286 fhandle=0xf1f7c10b
> >    offset=1048759 count=1048576 mem_align=4 offset_align=512
> >    start=1048759+329 middle=1049088+1048064 end=2097152+183
> >
> >    python3-32744   [006] .l... 132946.352360:
> >    nfs_local_dio_misaligned: fileid=00:33:1286 fhandle=0xf1f7c10b
> >    offset=329 count=1048064 mem_align=4 offset_align=512
> >    start=329+329 middle=1049088+1048064 end=2097152+183
> >
> > After this fix:
> >
> >    python3-32744   [006] .l... 132946.352360:
> >    nfs_local_dio_write: fileid=00:33:1286 fhandle=0xf1f7c10b
> >    offset=1048759 count=1048576 mem_align=4 offset_align=512
> >    start=1048759+329 middle=1049088+1048064 end=2097152+183
> >
> >    python3-32744   [006] .l... 132946.352360:
> >    nfs_local_dio_misaligned: fileid=00:33:1286 fhandle=0xf1f7c10b
> >    offset=1049088 count=1048064 mem_align=4 offset_align=512
> >    start=1048759+329 middle=1049088+1048064 end=2097152+183
> >
> > Cc: stable@vger.kernel.org
> 
> Do you have a fixes tag for this commit?
>
> Thanks,
> Anna

Sorry, I somehow missed this until now.  Looks to be:

Fixes: 6a218b9c3183e ("nfs/localio: do not issue misaligned DIO out-of-order")