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From: Dmitry Monakhov <dmonakhov@openvz.org>
To: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
	Dmitry Monakhov <dmonakhov@openvz.org>
Subject: [PATCH 00/16] fs: fixup racy check file->f_flags for xxx_write_iter
Date: Sat,  4 Apr 2015 23:13:09 +0400	[thread overview]
Message-ID: <1428174805-853-1-git-send-email-dmonakhov@openvz.org> (raw)

There are many places inside vfs/fs where code flow depends on file->f_flags,
but this check is racy because one can change it via fcntl(,F_SETFL,)
For example O_DIRECT usually flag checked twice:
  xxx_file_write_iter -> check O_DIRECT, and perform some optimizations
    ->__generic_file_write_iter -> check O_DIRECT,
which may break things: for example http://www.spinics.net/lists/linux-ext4/msg45683.html
For that reason some filesystems simply do not use __generic_file_write_iter()
wihch result in code duplication. Right way to fix this is to save volatile flags
inside kiocb->ki_flags similar to ->ki_pos
Other private discussion: message-id:20141218105101.GD13705@quack.suse.cz

TOC:
##First two patches introduce helpers and update generic code
kiocb_flags-v1/0001-fs-save-file-f_flags-to-kiocb-ki_flags.patch
kiocb_flags-v1/0002-vfs-check-kiocb-ki_flags-instead-filp-fl_flags.patch
## Switch filesystems to kiocb->ki_flags
kiocb_flags-v1/0003-ext4-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0004-9p-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0005-btrfs-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0006-ceph-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0007-cifs-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0008-gfs2-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0009-nfs-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0010-ntfs-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0011-ocfs2-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0012-udf-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0013-xfs-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0014-fuse-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
## Fix pipe and splice issues caused by race with fcntl(,F_SETFL,)
kiocb_flags-v1/0015-pipe-use-is_xxx_kiocb-instead-of-filp-fl_flags.patch
kiocb_flags-v1/0016-splice-fix-race-beween-splice_write-vs-fcntl-F_SETFL.patch

Patch set survived basic run of xfstests

             reply	other threads:[~2015-04-04 19:13 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-04 19:13 Dmitry Monakhov [this message]
2015-04-04 19:13 ` [PATCH 01/16] fs: save file->f_flags to kiocb->ki_flags Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 02/16] vfs: check kiocb->ki_flags instead filp->fl_flags Dmitry Monakhov
2015-04-04 21:36   ` Al Viro
2015-04-05 11:03     ` Dmitry Monakhov
2015-04-05 18:11       ` Al Viro
2015-04-05 21:54         ` Al Viro
2015-04-04 19:13 ` [PATCH 03/16] ext4: use is_xxx_kiocb instead of filp->fl_flags Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 04/16] 9p: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 05/16] btrfs: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 06/16] ceph: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 07/16] cifs: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 08/16] gfs2: " Dmitry Monakhov
2015-04-04 19:13   ` [Cluster-devel] " Dmitry Monakhov
2015-04-07 13:11   ` Steven Whitehouse
2015-04-07 13:11     ` Steven Whitehouse
2015-04-04 19:13 ` [PATCH 09/16] nfs: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 10/16] ntfs: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 11/16] ocfs2: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 12/16] udf: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 13/16] xfs: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 14/16] fuse: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 15/16] pipe: " Dmitry Monakhov
2015-04-04 19:13 ` [PATCH 16/16] splice: fix race beween splice_write vs fcntl(,F_SETFL,) Dmitry Monakhov

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