From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AA1543F660B for ; Wed, 8 Jul 2026 21:36:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783546572; cv=none; b=Y/Mu/GiqQgtJJZpQZQoMsY/TWDBmHyrQT70SmvK+OPs7SLvnHgI24XzJVcKqSHdvt+rzTAeme95QP5IUtQ6QV92pl+wdqysmdnrsiv3/IC+p5casHQkIA7dB+QiB24F31vXKO/2at2LHmKQoloiRp7RoHysd9HEyHLZ8Mq9Jj80= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783546572; c=relaxed/simple; bh=QS+IUibvFypmp6z30K+ypyfMnYBK+q0hsLN/1IRqrck=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=T+2QEpGlxWSMZj+Jsqbh7UsImLIYP+uSOs/2AH9sfJqPUyddWDerwhrgwu38TBQL+99oGMpZ7lnk9zn5lX16YYXRz203UyAEqenCNej2wcnB2yfywaUrX2OVi/AaZUN5b8GWZcH6ELnNIElCk44tQs8Cuxbr8dGgCNAB33y8oCA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CogA/i6Q; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CogA/i6Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EA431F000E9; Wed, 8 Jul 2026 21:36:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783546571; bh=QwSZtvo5U3/02/7GPdS94ANhEIkqFoBWzThwqIP3Ca0=; h=From:To:Cc:Subject:Date; b=CogA/i6QXAROt44fuX/qOsk/GYkLgfuCSg+uq+zzzug4bhcK77MMvQ8DJPngrkS6G 9mo8UNp74R4b8Djdm81td5h+sEk3P/wHnIwi57bQFfL1QLWebs9UdNntKHTYg6OZKn cQwhino5eRYYMB9UUYXQY728BLjjUK793m3z4ODeZy8vvQD6jNVFTmUm/APdgofgai 5eMkLmjEKk28vAL278PlkWdHdCESMZPi9vKqc7cHoE3he6KIzaqkllPfwOC2cJ1Scl ZkKbmqfJo4zRrvm1Kqjg0UkaQaw6VMwm4iQxKPnaEXXuUu5HCt0qvmtzYV+ezjVMrK eWuYGKlVzF+BA== From: Mike Snitzer To: Trond Myklebust , Anna Schumaker Cc: linux-nfs@vger.kernel.org Subject: [PATCH] NFS/localio: fix nfs_local_dio_misaligned tracepoint Date: Wed, 8 Jul 2026 17:36:10 -0400 Message-ID: <20260708213610.19001-1-snitzer@kernel.org> X-Mailer: git-send-email 2.44.0 Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Mike Snitzer --- fs/nfs/localio.c | 2 +- fs/nfs/nfstrace.h | 5 ++++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c index f42b6112a613..63c38dea50cc 100644 --- a/fs/nfs/localio.c +++ b/fs/nfs/localio.c @@ -446,7 +446,7 @@ nfs_local_iters_setup_dio(struct nfs_local_kiocb *iocb, int rw, if (unlikely(!iocb->iter_is_dio_aligned[n_iters])) { trace_nfs_local_dio_misaligned(iocb->hdr->inode, - local_dio->start_len, local_dio->middle_len, local_dio); + local_dio->middle_offset, local_dio->middle_len, local_dio); return 0; /* no DIO-aligned IO possible */ } iocb->end_iter_index = n_iters; diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h index c70debb88aa1..2e1932962a81 100644 --- a/fs/nfs/nfstrace.h +++ b/fs/nfs/nfstrace.h @@ -1772,7 +1772,10 @@ DECLARE_EVENT_CLASS(nfs_local_dio_class, __entry->count = count; __entry->mem_align = local_dio->mem_align; __entry->offset_align = local_dio->offset_align; - __entry->start = offset; + if (local_dio->start_len) + __entry->start = local_dio->middle_offset - local_dio->start_len; + else + __entry->start = 0; __entry->start_len = local_dio->start_len; __entry->middle = local_dio->middle_offset; __entry->middle_len = local_dio->middle_len; -- 2.43.0