fs: Add helper to clean bdev aliases under a bh and use it

Add a helper function that clears buffer heads from a block device
aliasing passed bh. Use this helper function from filesystems instead of
the original unmap_underlying_metadata() to save some boiler plate code
and also have a better name for the functionalily since it is not
unmapping anything for a *long* time.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

fs/buffer.c

@@ -1821,8 +1821,7 @@ int __block_write_full_page(struct inode *inode, struct page *page,
 			if (buffer_new(bh)) {
 				/* blockdev mappings never come here */
 				clear_buffer_new(bh);
-				unmap_underlying_metadata(bh->b_bdev,
+				clean_bdev_bh_alias(bh);
-							bh->b_blocknr);
 			}
 		}
 		bh = bh->b_this_page;
@@ -2068,8 +2067,7 @@ int __block_write_begin_int(struct page *page, loff_t pos, unsigned len,
 			}
 
 			if (buffer_new(bh)) {
-				unmap_underlying_metadata(bh->b_bdev,
+				clean_bdev_bh_alias(bh);
-							bh->b_blocknr);
 				if (PageUptodate(page)) {
 					clear_buffer_new(bh);
 					set_buffer_uptodate(bh);
@@ -2709,7 +2707,7 @@ int nobh_write_begin(struct address_space *mapping,
 		if (!buffer_mapped(bh))
 			is_mapped_to_disk = 0;
 		if (buffer_new(bh))
-			unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+			clean_bdev_bh_alias(bh);
 		if (PageUptodate(page)) {
 			set_buffer_uptodate(bh);
 			continue;

fs/ext4/inode.c

@@ -1123,8 +1123,7 @@ static int ext4_block_write_begin(struct page *page, loff_t pos, unsigned len,
 			if (err)
 				break;
 			if (buffer_new(bh)) {
-				unmap_underlying_metadata(bh->b_bdev,
+				clean_bdev_bh_alias(bh);
-							  bh->b_blocknr);
 				if (PageUptodate(page)) {
 					clear_buffer_new(bh);
 					set_buffer_uptodate(bh);

fs/ext4/page-io.c

@@ -457,7 +457,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
 		}
 		if (buffer_new(bh)) {
 			clear_buffer_new(bh);
-			unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+			clean_bdev_bh_alias(bh);
 		}
 		set_buffer_async_write(bh);
 		nr_to_submit++;

fs/mpage.c

@@ -555,8 +555,7 @@ static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
 		if (mpd->get_block(inode, block_in_file, &map_bh, 1))
 			goto confused;
 		if (buffer_new(&map_bh))
-			unmap_underlying_metadata(map_bh.b_bdev,
+			clean_bdev_bh_alias(&map_bh);
-						map_bh.b_blocknr);
 		if (buffer_boundary(&map_bh)) {
 			boundary_block = map_bh.b_blocknr;
 			boundary_bdev = map_bh.b_bdev;

fs/ntfs/aops.c

@@ -765,7 +765,7 @@ static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
 			}
 			// TODO: Instantiate the hole.
 			// clear_buffer_new(bh);
-			// unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+			// clean_bdev_bh_alias(bh);
 			ntfs_error(vol->sb, "Writing into sparse regions is "
 					"not supported yet. Sorry.");
 			err = -EOPNOTSUPP;

fs/ntfs/file.c

@@ -740,8 +740,7 @@ static int ntfs_prepare_pages_for_non_resident_write(struct page **pages,
 					set_buffer_uptodate(bh);
 				if (unlikely(was_hole)) {
 					/* We allocated the buffer. */
-					unmap_underlying_metadata(bh->b_bdev,
+					clean_bdev_bh_alias(bh);
-							bh->b_blocknr);
 					if (bh_end <= pos || bh_pos >= end)
 						mark_buffer_dirty(bh);
 					else
@@ -784,7 +783,7 @@ static int ntfs_prepare_pages_for_non_resident_write(struct page **pages,
 				continue;
 			}
 			/* We allocated the buffer. */
-			unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+			clean_bdev_bh_alias(bh);
 			/*
 			 * If the buffer is fully outside the write, zero it,
 			 * set it uptodate, and mark it dirty so it gets

fs/ocfs2/aops.c

@@ -630,7 +630,7 @@ int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
 
 		if (!buffer_mapped(bh)) {
 			map_bh(bh, inode->i_sb, *p_blkno);
-			unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+			clean_bdev_bh_alias(bh);
 		}
 
 		if (PageUptodate(page)) {

fs/ufs/balloc.c

@@ -307,8 +307,7 @@ static void ufs_change_blocknr(struct inode *inode, sector_t beg,
 			     (unsigned long long)(pos + newb), pos);
 
 			bh->b_blocknr = newb + pos;
-			unmap_underlying_metadata(bh->b_bdev,
+			clean_bdev_bh_alias(bh);
-						  bh->b_blocknr);
 			mark_buffer_dirty(bh);
 			++j;
 			bh = bh->b_this_page;

fs/ufs/inode.c

@@ -1070,8 +1070,7 @@ static int ufs_alloc_lastblock(struct inode *inode, loff_t size)
 
        if (buffer_new(bh)) {
 	       clear_buffer_new(bh);
-	       unmap_underlying_metadata(bh->b_bdev,
+	       clean_bdev_bh_alias(bh);
-					 bh->b_blocknr);
 	       /*
 		* we do not zeroize fragment, because of
 		* if it maped to hole, it already contains zeroes

include/linux/buffer_head.h

@@ -171,6 +171,10 @@ 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)
+{
+	clean_bdev_aliases(bh->b_bdev, bh->b_blocknr, 1);
+}
 
 void mark_buffer_async_write(struct buffer_head *bh);
 void __wait_on_buffer(struct buffer_head *);