From patchwork Wed Feb 26 09:57:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ritesh Harjani X-Patchwork-Id: 1244871 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48SB7F2J7cz9sRJ for ; Wed, 26 Feb 2020 20:57:45 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727938AbgBZJ5o (ORCPT ); Wed, 26 Feb 2020 04:57:44 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:12774 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727909AbgBZJ5o (ORCPT ); Wed, 26 Feb 2020 04:57:44 -0500 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 01Q9p8Fd106434 for ; Wed, 26 Feb 2020 04:57:43 -0500 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ydcnt8ant-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 26 Feb 2020 04:57:42 -0500 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 26 Feb 2020 09:57:36 -0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 01Q9vZ7133030178 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Feb 2020 09:57:35 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6E81642047; Wed, 26 Feb 2020 09:57:35 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 41B304203F; Wed, 26 Feb 2020 09:57:33 +0000 (GMT) Received: from localhost.localdomain.com (unknown [9.199.47.18]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 26 Feb 2020 09:57:33 +0000 (GMT) From: Ritesh Harjani To: jack@suse.cz, tytso@mit.edu, linux-ext4@vger.kernel.org Cc: adilger.kernel@dilger.ca, linux-fsdevel@vger.kernel.org, darrick.wong@oracle.com, hch@infradead.org, cmaiolino@redhat.com, Ritesh Harjani Subject: [PATCHv3 6/6] Documentation: Correct the description of FIEMAP_EXTENT_LAST Date: Wed, 26 Feb 2020 15:27:08 +0530 X-Mailer: git-send-email 2.21.0 In-Reply-To: References: MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 20022609-0016-0000-0000-000002EA626D X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20022609-0017-0000-0000-0000334D9138 Message-Id: <279638c6939b1f6ef3ab32912cb51da1a967cf8e.1582702694.git.riteshh@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.572 definitions=2020-02-26_02:2020-02-25,2020-02-26 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 adultscore=0 lowpriorityscore=0 impostorscore=0 clxscore=1015 malwarescore=0 spamscore=0 suspectscore=0 mlxscore=0 bulkscore=0 phishscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002260074 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Currently FIEMAP_EXTENT_LAST is not working consistently across different filesystem's fiemap implementations and thus this feature may be broken. So fix the documentation about this flag to meet the right expectations. Signed-off-by: Ritesh Harjani --- Documentation/filesystems/fiemap.txt | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/Documentation/filesystems/fiemap.txt b/Documentation/filesystems/fiemap.txt index f6d9c99103a4..7c5d22511df7 100644 --- a/Documentation/filesystems/fiemap.txt +++ b/Documentation/filesystems/fiemap.txt @@ -71,8 +71,7 @@ allocated is less than would be required to map the requested range, the maximum number of extents that can be mapped in the fm_extent[] array will be returned and fm_mapped_extents will be equal to fm_extent_count. In that case, the last extent in the array will not -complete the requested range and will not have the FIEMAP_EXTENT_LAST -flag set (see the next section on extent flags). +complete the requested range. Each extent is described by a single fiemap_extent structure as returned in fm_extents. @@ -96,7 +95,7 @@ block size of the file system. With the exception of extents flagged as FIEMAP_EXTENT_MERGED, adjacent extents will not be merged. The fe_flags field contains flags which describe the extent returned. -A special flag, FIEMAP_EXTENT_LAST is always set on the last extent in +A special flag, FIEMAP_EXTENT_LAST *may be* set on the last extent in the file so that the process making fiemap calls can determine when no more extents are available, without having to call the ioctl again. @@ -115,8 +114,9 @@ data. Note that the opposite is not true - it would be valid for FIEMAP_EXTENT_NOT_ALIGNED to appear alone. * FIEMAP_EXTENT_LAST -This is the last extent in the file. A mapping attempt past this -extent will return nothing. +This is generally the last extent in the file. A mapping attempt past this +extent may return nothing. But the user must still confirm by trying to map +past this extent, since different filesystems implement this differently. * FIEMAP_EXTENT_UNKNOWN The location of this extent is currently unknown. This may indicate