[PATCH 1/7] block: use i_size_write() in bd_set_size()

[Guo Chao <yan@linux.vnet.ibm.com>]

blkdev_ioctl(GETBLKSIZE) uses i_size_read() to read size
of block device. If we update block size directly, reader
may see intermediate result in some machines and configurations.
Use i_size_write() instead.

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Guo Chao <yan@linux.vnet.ibm.com>
---
 fs/block_dev.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 172f849..82b7c9a 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1032,7 +1032,9 @@ void bd_set_size(struct block_device *bdev, loff_t size)
 {
 	unsigned bsize = bdev_logical_block_size(bdev);
 
-	bdev->bd_inode->i_size = size;
+	mutex_lock(&bdev->bd_inode->i_mutex);
+	i_size_write(bdev->bd_inode, size);
+	mutex_unlock(&bdev->bd_inode->i_mutex);
 	while (bsize < PAGE_CACHE_SIZE) {
 		if (size & bsize)
 			break;
-- 
1.7.9.5