From: Li Zefan <lizf@cn.fujitsu.com>
Date: Fri, 2 Sep 2011 07:56:55 +0000 (+0800)
Subject: Btrfs: fix wrong max_to_defrag in btrfs_defrag_file()
X-Git-Tag: v2.6.39-400.9.0~845^2~51
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=75ecf653881b72b623a827022050b3f2d5b939a9;p=users%2Fjedix%2Flinux-maple.git

Btrfs: fix wrong max_to_defrag in btrfs_defrag_file()

It's off-by-one, and thus we may skip the last page while defragmenting.

An example case:

  # create /mnt/file with 2 4K file extents
  # btrfs fi defrag /mnt/file
  # sync
  # filefrag /mnt/file
  /mnt/file: 2 extents found

So it's not defragmented.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
(cherry picked from commit 5ca496604b5975d371bb669ee6c2394bcbea818f)
---

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 817487162f1b..066280b7fb58 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1061,7 +1061,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
 		i = range->start >> PAGE_CACHE_SHIFT;
 	}
 	if (!max_to_defrag)
-		max_to_defrag = last_index - 1;
+		max_to_defrag = last_index;
 
 	/*
 	 * make writeback starts from i, so the defrag range can be