block: read i_size with i_size_read()

Convert direct reads of an inode's i_size to using i_size_read().

i_size_{read,write} use a seqcount to protect reads from accessing
incomple writes.  Concurrent i_size_write()s require mutual exclussion
to protect the seqcount that is used by i_size_{read,write}.  But
i_size_read() callers do not need to use additional locking.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: NeilBrown <neilb@suse.de>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/block/ioctl.c b/block/ioctl.c
index d724ceb1d465..38aa194f63ec 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -125,7 +125,7 @@ static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
         start >>= 9;
         len >>= 9;
 
-        if (start + len > (bdev->bd_inode->i_size >> 9))
+        if (start + len > (i_size_read(bdev->bd_inode) >> 9))
                 return -EINVAL;
         if (secure)
                 flags |= BLKDEV_DISCARD_SECURE;
@@ -307,12 +307,12 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
                 ret = blkdev_reread_part(bdev);
                 break;
         case BLKGETSIZE:
-                size = bdev->bd_inode->i_size;
+                size = i_size_read(bdev->bd_inode);
                 if ((size >> 9) > ~0UL)
                         return -EFBIG;
                 return put_ulong(arg, size >> 9);
         case BLKGETSIZE64:
-                return put_u64(arg, bdev->bd_inode->i_size);
+                return put_u64(arg, i_size_read(bdev->bd_inode));
         case BLKTRACESTART:
         case BLKTRACESTOP:
         case BLKTRACESETUP: