NTFS: - In fs/ntfs/compress.c, use i_size_read() at the start and then use the

cached value everywhere.  Cache the initialized_size in the same way
	and protect the critical region where the two sizes are read using the
	new size_lock of the ntfs inode.
      - Add the new size_lock to the ntfs_inode structure (fs/ntfs/inode.h)
	and initialize it (fs/ntfs/inode.c).

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

fs/ntfs/inode.c

@@ -376,6 +376,7 @@ static void ntfs_destroy_extent_inode(ntfs_inode *ni)
 void __ntfs_init_inode(struct super_block *sb, ntfs_inode *ni)
 {
 	ntfs_debug("Entering.");
+	rwlock_init(&ni->size_lock);
 	ni->initialized_size = ni->allocated_size = 0;
 	ni->seq_no = 0;
 	atomic_set(&ni->count, 1);