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>

5 files changed, 18 insertions, 18 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:
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 9bdcf4393c0a..2637f499f77f 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1874,7 +1874,7 @@ static inline sector_t drbd_md_last_sector(struct drbd_backing_dev *bdev)
 static inline sector_t drbd_get_capacity(struct block_device *bdev)
 {
         /* return bdev ? get_capacity(bdev->bd_disk) : 0; */
-        return bdev ? bdev->bd_inode->i_size >> 9 : 0;
+        return bdev ? i_size_read(bdev->bd_inode) >> 9 : 0;
 }
 
 /**
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4e957f3140a8..324a3663fcda 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -706,7 +706,7 @@ static struct mdk_personality *find_pers(int level, char *clevel)
 /* return the offset of the super block in 512byte sectors */
 static inline sector_t calc_dev_sboffset(struct block_device *bdev)
 {
-        sector_t num_sectors = bdev->bd_inode->i_size / 512;
+        sector_t num_sectors = i_size_read(bdev->bd_inode) / 512;
         return MD_NEW_SIZE_SECTORS(num_sectors);
 }
 
@@ -1386,7 +1386,7 @@ static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
          */
         switch(minor_version) {
         case 0:
-                sb_start = rdev->bdev->bd_inode->i_size >> 9;
+                sb_start = i_size_read(rdev->bdev->bd_inode) >> 9;
                 sb_start -= 8*2;
                 sb_start &= ~(sector_t)(4*2-1);
                 break;
@@ -1472,7 +1472,7 @@ static int super_1_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version)
                         ret = 0;
         }
         if (minor_version)
-                rdev->sectors = (rdev->bdev->bd_inode->i_size >> 9) -
+                rdev->sectors = (i_size_read(rdev->bdev->bd_inode) >> 9) -
                         le64_to_cpu(sb->data_offset);
         else
                 rdev->sectors = rdev->sb_start;
@@ -1680,7 +1680,7 @@ super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
                 return 0; /* component must fit device */
         if (rdev->sb_start < rdev->data_offset) {
                 /* minor versions 1 and 2; superblock before data */
-                max_sectors = rdev->bdev->bd_inode->i_size >> 9;
+                max_sectors = i_size_read(rdev->bdev->bd_inode) >> 9;
                 max_sectors -= rdev->data_offset;
                 if (!num_sectors || num_sectors > max_sectors)
                         num_sectors = max_sectors;
@@ -1690,7 +1690,7 @@ super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
         } else {
                 /* minor version 0; superblock after data */
                 sector_t sb_start;
-                sb_start = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
+                sb_start = (i_size_read(rdev->bdev->bd_inode) >> 9) - 8*2;
                 sb_start &= ~(sector_t)(4*2 - 1);
                 max_sectors = rdev->sectors + sb_start - rdev->sb_start;
                 if (!num_sectors || num_sectors > max_sectors)
@@ -2584,7 +2584,7 @@ rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                         if (!sectors)
                                 return -EBUSY;
                 } else if (!sectors)
-                        sectors = (rdev->bdev->bd_inode->i_size >> 9) -
+                        sectors = (i_size_read(rdev->bdev->bd_inode) >> 9) -
                                 rdev->data_offset;
         }
         if (sectors < my_mddev->dev_sectors)
@@ -2797,7 +2797,7 @@ static mdk_rdev_t *md_import_device(dev_t newdev, int super_format, int super_mi
 
         kobject_init(&rdev->kobj, &rdev_ktype);
 
-        size = rdev->bdev->bd_inode->i_size >> BLOCK_SIZE_BITS;
+        size = i_size_read(rdev->bdev->bd_inode) >> BLOCK_SIZE_BITS;
         if (!size) {
                 printk(KERN_WARNING 
                         "md: %s has zero or unknown size, marking faulty!\n",
@@ -5235,8 +5235,8 @@ static int add_new_disk(mddev_t * mddev, mdu_disk_info_t *info)
 
                 if (!mddev->persistent) {
                         printk(KERN_INFO "md: nonpersistent superblock ...\n");
-                        rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
-                } else 
+                        rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
+                } else
                         rdev->sb_start = calc_dev_sboffset(rdev->bdev);
                 rdev->sectors = rdev->sb_start;
 
@@ -5306,7 +5306,7 @@ static int hot_add_disk(mddev_t * mddev, dev_t dev)
         if (mddev->persistent)
                 rdev->sb_start = calc_dev_sboffset(rdev->bdev);
         else
-                rdev->sb_start = rdev->bdev->bd_inode->i_size / 512;
+                rdev->sb_start = i_size_read(rdev->bdev->bd_inode) / 512;
 
         rdev->sectors = rdev->sb_start;