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, 10 insertions, 10 deletions

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;