fs: add i_blocksize()

commit 93407472a21b82f39c955ea7787e5bc7da100642 upstream.

Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs
branch.

This patch also fixes multiple checkpatch warnings: WARNING: Prefer
'unsigned int' to bare use of 'unsigned'

Thanks to Andrew Morton for suggesting more appropriate function instead
of macro.

[geliangtang@gmail.com: truncate: use i_blocksize()]
  Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com
Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 000c234..0db6f83 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -808,7 +808,7 @@ static int ocfs2_write_zero_page(struct inode *inode, u64 abs_from,
 	/* We know that zero_from is block aligned */
 	for (block_start = zero_from; block_start < zero_to;
 	     block_start = block_end) {
-		block_end = block_start + (1 << inode->i_blkbits);
+		block_end = block_start + i_blocksize(inode);
 
 		/*
 		 * block_start is block-aligned.  Bump it by one to force