Commit 5657e8fa authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Alasdair G Kergon
Browse files

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: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 8cbeb67a

drivers/md/dm-exception-store.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -156,7 +156,7 @@ static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e) 
 */

 */

static inline sector_t get_dev_size(struct block_device *bdev)

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,

static inline chunk_t sector_to_chunk(struct dm_exception_store *store,

drivers/md/dm-log.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -416,7 +416,7 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti, 
				       bitset_size,

				       bitset_size,

				       ti->limits.logical_block_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",

			DMWARN("log device %s too small: need %llu bytes",

				dev->name, (unsigned long long)buf_size);

				dev->name, (unsigned long long)buf_size);

			kfree(lc);

			kfree(lc);

drivers/md/dm-table.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -388,7 +388,8 @@ static void close_dev(struct dm_dev_internal *d, struct mapped_device *md) 
static int check_device_area(struct dm_dev_internal *dd, sector_t start,

static int check_device_area(struct dm_dev_internal *dd, sector_t start,

			     sector_t len)

			     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)

	if (!dev_size)

		return 1;

		return 1;

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