releases/3.8.4/block-use-i_size_write-in-bd_set_size.patch

   1 From d646a02a9d44d1421f273ae3923d97b47b918176 Mon Sep 17 00:00:00 2001
   2 From: Guo Chao <yan@linux.vnet.ibm.com>
   3 Date: Thu, 21 Feb 2013 15:16:42 -0800
   4 Subject: block: use i_size_write() in bd_set_size()
   5
   6 From: Guo Chao <yan@linux.vnet.ibm.com>
   7
   8 commit d646a02a9d44d1421f273ae3923d97b47b918176 upstream.
   9
  10 blkdev_ioctl(GETBLKSIZE) uses i_size_read() to read size of block device.
  11 If we update block size directly, reader may see intermediate result in
  12 some machines and configurations.  Use i_size_write() instead.
  13
  14 Signed-off-by: Guo Chao <yan@linux.vnet.ibm.com>
  15 Cc: Alexander Viro <viro@zeniv.linux.org.uk>
  16 Cc: Guo Chao <yan@linux.vnet.ibm.com>
  17 Cc: M. Hindess <hindessm@uk.ibm.com>
  18 Cc: Nikanth Karthikesan <knikanth@suse.de>
  19 Cc: Jens Axboe <axboe@kernel.dk>
  20 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  21 Signed-off-by: Jens Axboe <axboe@kernel.dk>
  22 Acked-by: Jeff Mahoney <jeffm@suse.com>
  23 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  24
  25 ---
  26  fs/block_dev.c |    4 +++-
  27  1 file changed, 3 insertions(+), 1 deletion(-)
  28
  29 --- a/fs/block_dev.c
  30 +++ b/fs/block_dev.c
  31 @@ -1033,7 +1033,9 @@ void bd_set_size(struct block_device *bd
  32  {
  33         unsigned bsize = bdev_logical_block_size(bdev);
  34
  35 -       bdev->bd_inode->i_size = size;
  36 +       mutex_lock(&bdev->bd_inode->i_mutex);
  37 +       i_size_write(bdev->bd_inode, size);
  38 +       mutex_unlock(&bdev->bd_inode->i_mutex);
  39         while (bsize < PAGE_CACHE_SIZE) {
  40                 if (size & bsize)
  41                         break;