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From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
	Theodore Ts'o <tytso@mit.edu>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Chinner <david@fromorbit.com>, Jan Kara <jack@suse.com>,
	Jens Axboe <axboe@kernel.dk>,
	Matthew Wilcox <willy@linux.intel.com>,
	linux-block@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-nvdimm@lists.01.org, xfs@oss.sgi.com
Subject: [PATCH v4 3/5] ext4: Online defrag not supported with DAX
Date: Mon, 22 Feb 2016 11:59:20 -0700	[thread overview]
Message-ID: <1456167562-28576-4-git-send-email-ross.zwisler@linux.intel.com> (raw)
In-Reply-To: <1456167562-28576-1-git-send-email-ross.zwisler@linux.intel.com>

Online defrag operations for ext4 are hard coded to use the page cache.
See ext4_ioctl() -> ext4_move_extents() -> move_extent_per_page()

When combined with DAX I/O, which circumvents the page cache, this can
result in data corruption.  This was observed with xfstests ext4/307 and
ext4/308.

Fix this by only allowing online defrag for non-DAX files.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/ioctl.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index a99b010..eae5917 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -583,6 +583,11 @@ group_extend_out:
 				 "Online defrag not supported with bigalloc");
 			err = -EOPNOTSUPP;
 			goto mext_out;
+		} else if (IS_DAX(inode)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online defrag not supported with DAX");
+			err = -EOPNOTSUPP;
+			goto mext_out;
 		}
 
 		err = mnt_want_write_file(filp);
-- 
2.5.0

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WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
	"Theodore Ts'o" <tytso@mit.edu>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Chinner <david@fromorbit.com>, Jan Kara <jack@suse.com>,
	Jens Axboe <axboe@kernel.dk>,
	Matthew Wilcox <willy@linux.intel.com>,
	linux-block@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-nvdimm@ml01.01.org, xfs@oss.sgi.com
Subject: [PATCH v4 3/5] ext4: Online defrag not supported with DAX
Date: Mon, 22 Feb 2016 11:59:20 -0700	[thread overview]
Message-ID: <1456167562-28576-4-git-send-email-ross.zwisler@linux.intel.com> (raw)
In-Reply-To: <1456167562-28576-1-git-send-email-ross.zwisler@linux.intel.com>

Online defrag operations for ext4 are hard coded to use the page cache.
See ext4_ioctl() -> ext4_move_extents() -> move_extent_per_page()

When combined with DAX I/O, which circumvents the page cache, this can
result in data corruption.  This was observed with xfstests ext4/307 and
ext4/308.

Fix this by only allowing online defrag for non-DAX files.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/ioctl.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index a99b010..eae5917 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -583,6 +583,11 @@ group_extend_out:
 				 "Online defrag not supported with bigalloc");
 			err = -EOPNOTSUPP;
 			goto mext_out;
+		} else if (IS_DAX(inode)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online defrag not supported with DAX");
+			err = -EOPNOTSUPP;
+			goto mext_out;
 		}
 
 		err = mnt_want_write_file(filp);
-- 
2.5.0

WARNING: multiple messages have this Message-ID (diff)
From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>, Theodore Ts'o <tytso@mit.edu>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-nvdimm@lists.01.org, xfs@oss.sgi.com,
	linux-block@vger.kernel.org, linux-mm@kvack.org,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Jan Kara <jack@suse.com>,
	linux-fsdevel@vger.kernel.org,
	Matthew Wilcox <willy@linux.intel.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	linux-ext4@vger.kernel.org,
	Dan Williams <dan.j.williams@intel.com>
Subject: [PATCH v4 3/5] ext4: Online defrag not supported with DAX
Date: Mon, 22 Feb 2016 11:59:20 -0700	[thread overview]
Message-ID: <1456167562-28576-4-git-send-email-ross.zwisler@linux.intel.com> (raw)
In-Reply-To: <1456167562-28576-1-git-send-email-ross.zwisler@linux.intel.com>

Online defrag operations for ext4 are hard coded to use the page cache.
See ext4_ioctl() -> ext4_move_extents() -> move_extent_per_page()

When combined with DAX I/O, which circumvents the page cache, this can
result in data corruption.  This was observed with xfstests ext4/307 and
ext4/308.

Fix this by only allowing online defrag for non-DAX files.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/ioctl.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index a99b010..eae5917 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -583,6 +583,11 @@ group_extend_out:
 				 "Online defrag not supported with bigalloc");
 			err = -EOPNOTSUPP;
 			goto mext_out;
+		} else if (IS_DAX(inode)) {
+			ext4_msg(sb, KERN_ERR,
+				 "Online defrag not supported with DAX");
+			err = -EOPNOTSUPP;
+			goto mext_out;
 		}
 
 		err = mnt_want_write_file(filp);
-- 
2.5.0

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  parent reply	other threads:[~2016-02-22 18:59 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-22 18:59 [PATCH v4 0/5] DAX fixes, move flushing calls to FS Ross Zwisler
2016-02-22 18:59 ` Ross Zwisler
2016-02-22 18:59 ` Ross Zwisler
2016-02-22 18:59 ` [PATCH v4 1/5] block: disable block device DAX by default Ross Zwisler
2016-02-22 18:59   ` Ross Zwisler
2016-02-22 18:59   ` Ross Zwisler
2016-02-22 18:59 ` [PATCH v4 2/5] ext2, ext4: only set S_DAX for regular inodes Ross Zwisler
2016-02-22 18:59   ` Ross Zwisler
2016-02-22 18:59   ` Ross Zwisler
2016-02-22 18:59 ` Ross Zwisler [this message]
2016-02-22 18:59   ` [PATCH v4 3/5] ext4: Online defrag not supported with DAX Ross Zwisler
2016-02-22 18:59   ` Ross Zwisler
2016-02-22 18:59 ` [PATCH v4 4/5] dax: give DAX clearing code correct bdev Ross Zwisler
2016-02-22 18:59   ` Ross Zwisler
2016-02-22 18:59   ` Ross Zwisler
2016-02-22 18:59 ` [PATCH v4 5/5] dax: move writeback calls into the filesystems Ross Zwisler
2016-02-22 18:59   ` Ross Zwisler
2016-02-22 18:59   ` Ross Zwisler

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