ocfs2: use i_size_read() to access i_size

Though ocfs2 uses inode->i_mutex to protect i_size, there are both
i_size_read/write() and direct accesses.  Clean up all direct access to
eliminate confusion.

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index 2487116..4bf2b76 100644
--- a/fs/ocfs2/extent_map.c
+++ b/fs/ocfs2/extent_map.c
@@ -852,20 +852,20 @@
 
 	down_read(&OCFS2_I(inode)->ip_alloc_sem);
 
-	if (*offset >= inode->i_size) {
+	if (*offset >= i_size_read(inode)) {
 		ret = -ENXIO;
 		goto out_unlock;
 	}
 
 	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 		if (whence == SEEK_HOLE)
-			*offset = inode->i_size;
+			*offset = i_size_read(inode);
 		goto out_unlock;
 	}
 
 	clen = 0;
 	cpos = *offset >> cs_bits;
-	cend = ocfs2_clusters_for_bytes(inode->i_sb, inode->i_size);
+	cend = ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
 
 	while (cpos < cend && !is_last) {
 		ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
@@ -904,8 +904,8 @@
 		extlen = clen;
 		extlen <<=  cs_bits;
 
-		if ((extoff + extlen) > inode->i_size)
-			extlen = inode->i_size - extoff;
+		if ((extoff + extlen) > i_size_read(inode))
+			extlen = i_size_read(inode) - extoff;
 		extoff += extlen;
 		if (extoff > *offset)
 			*offset = extoff;