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Commit 5657e8fa authored Jun 22, 2009 by Mikulas Patocka Committed by Alasdair G Kergon Jun 22, 2009

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>

parent 8cbeb67a

drivers/md/dm-exception-store.h

+1 −1

Original line number	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)
		{
		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,

drivers/md/dm-log.c

+1 −1

Original line number	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,
		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);

drivers/md/dm-table.c

+2 −1

Original line number	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,
		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;