AcoSail/kernel_optimize_test
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dm: use i_size_read

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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>
This commit is contained in:
Mikulas Patocka 2009-06-22 10:12:14 +01:00 committed by Alasdair G Kergon
parent 8cbeb67ad5
commit 5657e8fa45
3 changed files with 4 additions and 3 deletions
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2
drivers/md/dm-exception-store.h
View File

@ -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,

2
drivers/md/dm-log.c
View File

@ -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);

3
drivers/md/dm-table.c
View File

@ -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;