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>

3 files changed, 7 insertions, 7 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index f0834e2f5727..17fcb83670c0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1351,7 +1351,7 @@ static void handle_bad_sector(struct bio *bio)
                         bdevname(bio->bi_bdev, b),
                         bio->bi_rw,
                         (unsigned long long)bio->bi_sector + bio_sectors(bio),
-                        (long long)(bio->bi_bdev->bd_inode->i_size >> 9));
+                        (long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9));
 
         set_bit(BIO_EOF, &bio->bi_flags);
 }
@@ -1404,7 +1404,7 @@ static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
                 return 0;
 
         /* Test device or partition size, when known. */
-        maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
+        maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;
         if (maxsector) {
                 sector_t sector = bio->bi_sector;
 
diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
index 119f07b74dc0..58c6ee5b010c 100644
--- a/block/compat_ioctl.c
+++ b/block/compat_ioctl.c
@@ -744,13 +744,13 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
                 return 0;
         case BLKGETSIZE:
-                size = bdev->bd_inode->i_size;
+                size = i_size_read(bdev->bd_inode);
                 if ((size >> 9) > ~0UL)
                         return -EFBIG;
                 return compat_put_ulong(arg, size >> 9);
 
         case BLKGETSIZE64_32:
-                return compat_put_u64(arg, bdev->bd_inode->i_size);
+                return compat_put_u64(arg, i_size_read(bdev->bd_inode));
 
         case BLKTRACESETUP32:
         case BLKTRACESTART: /* compatible */
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: