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,
diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index 6fa8ccf..6352a9a 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -416,7 +416,7 @@
bitset_size,
ti->limits.logical_block_size);
- if (buf_size > dev->bdev->bd_inode->i_size) {
+ if (buf_size > i_size_read(dev->bdev->bd_inode)) {
DMWARN("log device %s too small: need %llu bytes",
dev->name, (unsigned long long)buf_size);
kfree(lc);
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index e9a73bb..0e2210c 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -388,7 +388,8 @@
static int check_device_area(struct dm_dev_internal *dd, sector_t start,
sector_t len)
{
- sector_t dev_size = dd->dm_dev.bdev->bd_inode->i_size >> SECTOR_SHIFT;
+ sector_t dev_size = i_size_read(dd->dm_dev.bdev->bd_inode) >>
+ SECTOR_SHIFT;
if (!dev_size)
return 1;