Btrfs: drop remaining LINUX_KERNEL_VERSION checks and compat code

Signed-off-by: NChris Mason <chris.mason@oracle.com>

fs/btrfs/compat.h

@@ -4,29 +4,4 @@
 #define btrfs_drop_nlink(inode) drop_nlink(inode)
 #define btrfs_inc_nlink(inode)	inc_nlink(inode)
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 27)
-static inline struct dentry *d_obtain_alias(struct inode *inode)
-{
-	struct dentry *d;
-
-	if (!inode)
-		return NULL;
-	if (IS_ERR(inode))
-		return ERR_CAST(inode);
-
-	d = d_alloc_anon(inode);
-	if (!d)
-		iput(inode);
-	return d;
-}
-#endif
-
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 28)
-# define  __pagevec_lru_add_file __pagevec_lru_add
-# define open_bdev_exclusive open_bdev_excl
-# define close_bdev_exclusive(bdev, mode) close_bdev_excl(bdev)
-typedef unsigned __bitwise__ fmode_t;
-#endif
-
-
 #endif /* _COMPAT_H_ */

fs/btrfs/extent-tree.c

@@ -869,11 +869,7 @@ static noinline int remove_extent_backref(struct btrfs_trans_handle *trans,
 static void btrfs_issue_discard(struct block_device *bdev,
 				u64 start, u64 len)
 {
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
 	blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL);
-#else
-	blkdev_issue_discard(bdev, start >> 9, len >> 9);
-#endif
 }
 #endif