From: Mikulas Patocka 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 Signed-off-by: Alasdair G Kergon --- drivers/md/dm-exception-store.h | 2 +- drivers/md/dm-exception-store.h | 2 +- drivers/md/dm-log.c | 2 +- drivers/md/dm-table.c | 3 ++- 3 files changed, 4 insertions(+), 3 deletions(-) Index: linux-2.6.30/drivers/md/dm-exception-store.h =================================================================== --- linux-2.6.30.orig/drivers/md/dm-exception-store.h +++ linux-2.6.30/drivers/md/dm-exception-store.h @@ -156,7 +156,7 @@ static inline void dm_consecutive_chunk_ */ 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, Index: linux-2.6.30/drivers/md/dm-log.c =================================================================== --- linux-2.6.30.orig/drivers/md/dm-log.c +++ linux-2.6.30/drivers/md/dm-log.c @@ -416,7 +416,7 @@ static int create_log_context(struct dm_ 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); Index: linux-2.6.30/drivers/md/dm-table.c =================================================================== --- linux-2.6.30.orig/drivers/md/dm-table.c +++ linux-2.6.30/drivers/md/dm-table.c @@ -388,7 +388,8 @@ static void close_dev(struct dm_dev_inte 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;