After commit a11a2bf4, "SUNRPC: Optimise away unnecessary data moves
in xdr_align_pages", Thu Aug 2 13:21:43 2012, READs larger than a
few hundred bytes via NFS/RDMA no longer work. This commit exposed
a long-standing bug in rpcrdma_inline_fixup().
I reproduce this with an rsize=4096 mount using the cthon04 basic
tests. Test 5 fails with an EIO error.
For my reproducer, kernel log shows:
NFS: server cheating in read reply: count 4096 > recvd 0
rpcrdma_inline_fixup() is zeroing the xdr_stream::page_len field,
and xdr_align_pages() is now returning that value to the READ XDR
decoder function.
That field is set up by xdr_inline_pages() by the READ XDR encoder
function. As far as I can tell, it is supposed to be left alone
after that, as it describes the dimensions of the reply xdr_stream,
not the contents of that stream.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=68391
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
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