From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id B094B7F50 for ; Sun, 15 Nov 2015 07:08:24 -0600 (CST) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay2.corp.sgi.com (Postfix) with ESMTP id 9F309304032 for ; Sun, 15 Nov 2015 05:08:21 -0800 (PST) Received: from mail-wm0-f53.google.com (mail-wm0-f53.google.com [74.125.82.53]) by cuda.sgi.com with ESMTP id ylMFD4LQE8sLohFD (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO) for ; Sun, 15 Nov 2015 05:08:15 -0800 (PST) Received: by wmww144 with SMTP id w144so85885721wmw.0 for ; Sun, 15 Nov 2015 05:08:15 -0800 (PST) From: Avi Kivity Subject: AIO read returns negative number for bytes read Message-ID: <564883BD.8070607@scylladb.com> Date: Sun, 15 Nov 2015 15:08:13 +0200 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="------------000802080702020200030301" List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com, linux-aio@kvack.org This is a multi-part message in MIME format. --------------000802080702020200030301 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Due to a bug in my program, I initiated a read beyond eof. Specifically, the file size is 13002 bytes and the read offset is 13312 (0x3400). I would expect such a read to return 0 bytes read, but io_getevents returns -310, which is suspiciously equal to (13002 - 13312). I attach a reproducer. 4.2.5-201.fc22.x86_64 Are my expectations incorrect, or is this a bug in aio or xfs? --------------000802080702020200030301 Content-Type: text/plain; charset=UTF-8; name="aio_read_fails.c" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="aio_read_fails.c" I2RlZmluZSBfR05VX1NPVVJDRQoKI2luY2x1ZGUgPGxpYmFpby5oPgojaW5jbHVkZSA8YXNz ZXJ0Lmg+CiNpbmNsdWRlIDxzdGRsaWIuaD4KI2luY2x1ZGUgPHN5cy90eXBlcy5oPgojaW5j bHVkZSA8dW5pc3RkLmg+CiNpbmNsdWRlIDxzdGRpby5oPgojaW5jbHVkZSA8c3lzL3N0YXQu aD4KI2luY2x1ZGUgPGZjbnRsLmg+CgppbnQgbWFpbihpbnQgYWMsIGNoYXIqKiBhdikgewog IGludCBmZDsKICBjaGFyKiBidWY7CiAgaW9fY29udGV4dF90IGlvYyA9IE5VTEw7CiAgaW50 IHI7CiAgc3RydWN0IGlvY2IgaW9jYjsKICBzdHJ1Y3QgaW9jYiAqaW9jYnBbMV07CiAgc3Ry dWN0IGlvX2V2ZW50IGlvZXY7CgogIGJ1ZiA9IGFsaWduZWRfYWxsb2MoNDA5NiwgNDA5Nio0 KTsKICBhc3NlcnQoYnVmKTsKICByID0gaW9fc2V0dXAoMSwgJmlvYyk7CiAgYXNzZXJ0KHIg PT0gMCk7CiAgZmQgPSBvcGVuKCJ0bXAudG1wIiwgT19SRFdSIHwgT19DUkVBVCB8IE9fRElS RUNULCAwNjAwKTsKICBhc3NlcnQoZmQgPj0gMCk7CiAgaW9fcHJlcF9wd3JpdGUoJmlvY2Is IGZkLCBidWYsIDQwOTYqNCwgMCk7CiAgaW9jYnBbMF0gPSAmaW9jYjsKICByID0gaW9fc3Vi bWl0KGlvYywgMSwgaW9jYnApOwogIGFzc2VydChyID09IDEpOwogIHIgPSBpb19nZXRldmVu dHMoaW9jLCAxLCAxLCAmaW9ldiwgTlVMTCk7CiAgYXNzZXJ0KHIgPT0gMSk7CiAgYXNzZXJ0 KGlvZXYucmVzID09IDQqNDA5Nik7CiAgZnRydW5jYXRlKGZkLCAxMzAwMik7CiAgaW9fcHJl cF9wcmVhZCgmaW9jYiwgZmQsIGJ1ZiwgODE5MiwgMTMzMTIpOwogIHIgPSBpb19zdWJtaXQo aW9jLCAxLCBpb2NicCk7CiAgYXNzZXJ0KHIgPT0gMSk7CiAgciA9IGlvX2dldGV2ZW50cyhp b2MsIDEsIDEsICZpb2V2LCBOVUxMKTsKICBhc3NlcnQociA9PSAxKTsKICBwcmludGYoInJl YWQgcmVzdWx0OiAlZFxuIiwgKGludClpb2V2LnJlcyk7CiAgcmV0dXJuIDA7Cn0K --------------000802080702020200030301 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs --------------000802080702020200030301--