dm: use i_size_read
Use i_size_read() instead of reading i_size.
If someone changes the size of the device simultaneously, i_size_read
is guaranteed to return a valid value (either the old one or the new one).
i_size can return some intermediate invalid value (on 32-bit computers
with 64-bit i_size, the reads to both halves of i_size can be interleaved
with updates to i_size, resulting in garbage being returned).
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
index c92701d..2442c8c 100644
--- a/drivers/md/dm-exception-store.h
+++ b/drivers/md/dm-exception-store.h
@@ -156,7 +156,7 @@
*/
static inline sector_t get_dev_size(struct block_device *bdev)
{
- return bdev->bd_inode->i_size >> SECTOR_SHIFT;
+ return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
}
static inline chunk_t sector_to_chunk(struct dm_exception_store *store,