Commit d646a02a9d44d1421f273ae3923d97b47b918176 upstream.
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.
Signed-off-by: Guo Chao <yan@xxxxxxxxxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Guo Chao <yan@xxxxxxxxxxxxxxxxxx>
Cc: M. Hindess <hindessm@xxxxxxxxxx>
Cc: Nikanth Karthikesan <knikanth@xxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 3.0 3.2 3.4 3.8
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Acked-by: Jeff Mahoney <jeffm@xxxxxxxx>
---
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;
--
Jeff Mahoney
SUSE Labs
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