On Sun, Jun 12, 2016 at 05:34:32PM -0700, Marc Eshel wrote:
> We are seeing a data corruption when putting very high load on the NFS V3
> client reading multi gigabyte files in parallel. The check-sum on the
> files is showing the corruption, and looking at the data we see data that
> in one block that belongs in another block but it is not the full block.
> The test is done on multiple set of hardware using different type of
> server including kNFS and Ganesha servers with EXT3 or GPFS file system.
> The only common part in all test are NFSv3 client on REHL7.0, 7.1, 7.2.
>
> The question is there anything up stream that might fix data corruption by
> the NFSv3 client, oo do we know if this problem might have been reported
> by other users.
>
> The only fix that I see that might be related is attached, can this
> explain a data corruption?
It should be pretty easy to check whether there've been any READ/WRITE
errors, and rule this out if not.
Is the data being read completely static? (So you can rule out e.g.
some subtle violation of close-to-open.)
Sorry, no special knowledge here.
--b.
>
> Thanks, Marc.
>
>
> Author: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> Date: Mon Aug 17 12:57:07 2015 -0500
>
> NFS: nfs_set_pgio_error sometimes misses errors
>
> We should ensure that we always set the pgio_header's error field
> if a READ or WRITE RPC call returns an error. The current code depends
> on 'hdr->good_bytes' always being initialised to a large value, which
> is not always done correctly by callers.
> When this happens, applications may end up missing important errors.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>
> diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
> index 4984bbe..7c5718b 100644
> --- a/fs/nfs/pagelist.c
> +++ b/fs/nfs/pagelist.c
> @@ -77,8 +77,8 @@ EXPORT_SYMBOL_GPL(nfs_pgheader_init);
> void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t
> pos)
> {
> spin_lock(&hdr->lock);
> - if (pos < hdr->io_start + hdr->good_bytes) {
> - set_bit(NFS_IOHDR_ERROR, &hdr->flags);
> + if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags)
> + || pos < hdr->io_start + hdr->good_bytes) {
> clear_bit(NFS_IOHDR_EOF, &hdr->flags);
> hdr->good_bytes = pos - hdr->io_start;
>
> \
>
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