linux-kernel - [PATCH 4.9 198/206] xfs: dont cap maximum dedupe request length

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Message-Id: <20170110131512.157491051@linuxfoundation.org>
Date:   Tue, 10 Jan 2017 14:38:01 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        Dave Chinner <dchinner@...hat.com>,
        Dave Chinner <david@...morbit.com>,
        Christoph Hellwig <hch@....de>
Subject: [PATCH 4.9 198/206] xfs: dont cap maximum dedupe request length

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------


From: "Darrick J. Wong" <darrick.wong@...cle.com>

commit 1bb33a98702d8360947f18a44349df75ba555d5d upstream.

After various discussions on linux-fsdevel, it has been decided that it
is not necessary to cap the length of a dedupe request, and that
correctly-written userspace client programs will be able to absorb the
change.  Therefore, remove the length clamping behavior.

Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
Reviewed-by: Dave Chinner <dchinner@...hat.com>
Signed-off-by: Dave Chinner <david@...morbit.com>
Cc: Christoph Hellwig <hch@....de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/xfs/xfs_file.c |    9 ---------
 1 file changed, 9 deletions(-)

--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -939,7 +939,6 @@ xfs_file_clone_range(
 				     len, false);
 }
 
-#define XFS_MAX_DEDUPE_LEN	(16 * 1024 * 1024)
 STATIC ssize_t
 xfs_file_dedupe_range(
 	struct file	*src_file,
@@ -950,14 +949,6 @@ xfs_file_dedupe_range(
 {
 	int		error;
 
-	/*
-	 * Limit the total length we will dedupe for each operation.
-	 * This is intended to bound the total time spent in this
-	 * ioctl to something sane.
-	 */
-	if (len > XFS_MAX_DEDUPE_LEN)
-		len = XFS_MAX_DEDUPE_LEN;
-
 	error = xfs_reflink_remap_range(src_file, loff, dst_file, dst_loff,
 				     len, true);
 	if (error)