Commit cbcc8326 authored Sep 02, 2011 by Li Zefan Committed by David Sterba Oct 20, 2011

Btrfs: fix defragmentation regression



There's an off-by-one bug:

  # create a file with lots of 4K file extents
  # btrfs fi defrag /mnt/file
  # sync
  # filefrag -v /mnt/file
  Filesystem type is: 9123683e
  File size of /mnt/file is 1228800 (300 blocks, blocksize 4096)
   ext logical physical expected length flags
     0       0     3372              64
     1      64     3136     3435      1
     2      65     3436     3136     64
     3     129     3201     3499      1
     4     130     3500     3201     64
     5     194     3266     3563      1
     6     195     3564     3266     64
     7     259     3331     3627      1
     8     260     3628     3331     40 eof

After this patch:

  ...
  # filefrag -v /mnt/file
  Filesystem type is: 9123683e
  File size of /mnt/file is 1228800 (300 blocks, blocksize 4096)
   ext logical physical expected length flags
     0       0     3372             300 eof
  /mnt/file: 1 extent found

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

parent 60ccf82f

fs/btrfs/ioctl.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -1087,7 +1087,6 @@ int btrfs_defrag_file(struct inode inode, struct file file,

		defrag_count += ret;
		balance_dirty_pages_ratelimited_nr(inode->i_mapping, ret);
		i += ret;

		if (newer_than) {
		if (newer_off == (u64)-1)
		@@ -1107,6 +1106,9 @@ int btrfs_defrag_file(struct inode inode, struct file file,
		break;
		}
		} else {
		if (ret > 0)
		i += ret;
		else
		i++;
		}
		}

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