fs: Remove unmap_underlying_metadata

Nobody is using this function anymore. Remove it.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

fs/buffer.c

@@ -1605,38 +1605,6 @@ void create_empty_buffers(struct page *page,
 }
 EXPORT_SYMBOL(create_empty_buffers);
 
-/*
- * We are taking a block for data and we don't want any output from any
- * buffer-cache aliases starting from return from that function and
- * until the moment when something will explicitly mark the buffer
- * dirty (hopefully that will not happen until we will free that block ;-)
- * We don't even need to mark it not-uptodate - nobody can expect
- * anything from a newly allocated buffer anyway. We used to used
- * unmap_buffer() for such invalidation, but that was wrong. We definitely
- * don't want to mark the alias unmapped, for example - it would confuse
- * anyone who might pick it with bread() afterwards...
- *
- * Also..  Note that bforget() doesn't lock the buffer.  So there can
- * be writeout I/O going on against recently-freed buffers.  We don't
- * wait on that I/O in bforget() - it's more efficient to wait on the I/O
- * only if we really need to.  That happens here.
- */
-void unmap_underlying_metadata(struct block_device *bdev, sector_t block)
-{
-	struct buffer_head *old_bh;
-
-	might_sleep();
-
-	old_bh = __find_get_block_slow(bdev, block);
-	if (old_bh) {
-		clear_buffer_dirty(old_bh);
-		wait_on_buffer(old_bh);
-		clear_buffer_req(old_bh);
-		__brelse(old_bh);
-	}
-}
-EXPORT_SYMBOL(unmap_underlying_metadata);
-
 /**
  * clean_bdev_aliases: clean a range of buffers in block device
  * @bdev: Block device to clean buffers in

include/linux/buffer_head.h

@@ -168,7 +168,6 @@ int inode_has_buffers(struct inode *);
 void invalidate_inode_buffers(struct inode *);
 int remove_inode_buffers(struct inode *inode);
 int sync_mapping_buffers(struct address_space *mapping);
-void unmap_underlying_metadata(struct block_device *bdev, sector_t block);
 void clean_bdev_aliases(struct block_device *bdev, sector_t block,
 			sector_t len);
 static inline void clean_bdev_bh_alias(struct buffer_head *bh)