fs: Convert block_read_full_page() to block_read_full_folio()

This function is NOT converted to handle large folios, so include
an assert that the filesystem isn't passing one in.  Otherwise, use
the folio functions instead of the page functions, where they exist.
Convert all filesystems which use block_read_full_page().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

1 files changed, 28 insertions, 25 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 225d03cd622d..ec0c52c8848e 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -314,7 +314,7 @@ static void decrypt_bh(struct work_struct *work)
 }
 
 /*
- * I/O completion handler for block_read_full_page() - pages
+ * I/O completion handler for block_read_full_folio() - pages
  * which come unlocked at the end of I/O.
  */
 static void end_buffer_async_read_io(struct buffer_head *bh, int uptodate)
@@ -1060,8 +1060,8 @@ __getblk_slow(struct block_device *bdev, sector_t block,
  * Also.  When blockdev buffers are explicitly read with bread(), they
  * individually become uptodate.  But their backing page remains not
  * uptodate - even if all of its buffers are uptodate.  A subsequent
- * block_read_full_page() against that page will discover all the uptodate
- * buffers, will set the page uptodate and will perform no I/O.
+ * block_read_full_folio() against that folio will discover all the uptodate
+ * buffers, will set the folio uptodate and will perform no I/O.
  */
 
 /**
@@ -2088,7 +2088,7 @@ static int __block_commit_write(struct inode *inode, struct page *page,
 
 	/*
 	 * If this is a partial write which happened to make all buffers
-	 * uptodate then we can optimize away a bogus readpage() for
+	 * uptodate then we can optimize away a bogus read_folio() for
 	 * the next read(). Here we 'discover' whether the page went
 	 * uptodate as a result of this (potentially partial) write.
 	 */
@@ -2137,12 +2137,12 @@ int block_write_end(struct file *file, struct address_space *mapping,
 
 	if (unlikely(copied < len)) {
 		/*
-		 * The buffers that were written will now be uptodate, so we
-		 * don't have to worry about a readpage reading them and
-		 * overwriting a partial write. However if we have encountered
-		 * a short write and only partially written into a buffer, it
-		 * will not be marked uptodate, so a readpage might come in and
-		 * destroy our partial write.
+		 * The buffers that were written will now be uptodate, so
+		 * we don't have to worry about a read_folio reading them
+		 * and overwriting a partial write. However if we have
+		 * encountered a short write and only partially written
+		 * into a buffer, it will not be marked uptodate, so a
+		 * read_folio might come in and destroy our partial write.
 		 *
 		 * Do the simplest thing, and just treat any short write to a
 		 * non uptodate page as a zero-length write, and force the
@@ -2245,26 +2245,28 @@ bool block_is_partially_uptodate(struct folio *folio, size_t from, size_t count)
 EXPORT_SYMBOL(block_is_partially_uptodate);
 
 /*
- * Generic "read page" function for block devices that have the normal
+ * Generic "read_folio" function for block devices that have the normal
  * get_block functionality. This is most of the block device filesystems.
- * Reads the page asynchronously --- the unlock_buffer() and
+ * Reads the folio asynchronously --- the unlock_buffer() and
  * set/clear_buffer_uptodate() functions propagate buffer state into the
- * page struct once IO has completed.
+ * folio once IO has completed.
  */
-int block_read_full_page(struct page *page, get_block_t *get_block)
+int block_read_full_folio(struct folio *folio, get_block_t *get_block)
 {
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio->mapping->host;
 	sector_t iblock, lblock;
 	struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
 	unsigned int blocksize, bbits;
 	int nr, i;
 	int fully_mapped = 1;
 
-	head = create_page_buffers(page, inode, 0);
+	VM_BUG_ON_FOLIO(folio_test_large(folio), folio);
+
+	head = create_page_buffers(&folio->page, inode, 0);
 	blocksize = head->b_size;
 	bbits = block_size_bits(blocksize);
 
-	iblock = (sector_t)page->index << (PAGE_SHIFT - bbits);
+	iblock = (sector_t)folio->index << (PAGE_SHIFT - bbits);
 	lblock = (i_size_read(inode)+blocksize-1) >> bbits;
 	bh = head;
 	nr = 0;
@@ -2282,10 +2284,11 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
 				WARN_ON(bh->b_size != blocksize);
 				err = get_block(inode, iblock, bh, 0);
 				if (err)
-					SetPageError(page);
+					folio_set_error(folio);
 			}
 			if (!buffer_mapped(bh)) {
-				zero_user(page, i * blocksize, blocksize);
+				folio_zero_range(folio, i * blocksize,
+						blocksize);
 				if (!err)
 					set_buffer_uptodate(bh);
 				continue;
@@ -2301,16 +2304,16 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
 	} while (i++, iblock++, (bh = bh->b_this_page) != head);
 
 	if (fully_mapped)
-		SetPageMappedToDisk(page);
+		folio_set_mappedtodisk(folio);
 
 	if (!nr) {
 		/*
-		 * All buffers are uptodate - we can set the page uptodate
+		 * All buffers are uptodate - we can set the folio uptodate
 		 * as well. But not if get_block() returned an error.
 		 */
-		if (!PageError(page))
-			SetPageUptodate(page);
-		unlock_page(page);
+		if (!folio_test_error(folio))
+			folio_mark_uptodate(folio);
+		folio_unlock(folio);
 		return 0;
 	}
 
@@ -2335,7 +2338,7 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
 	}
 	return 0;
 }
-EXPORT_SYMBOL(block_read_full_page);
+EXPORT_SYMBOL(block_read_full_folio);
 
 /* utility function for filesystems that need to do work on expanding
  * truncates.  Uses filesystem pagecache writes to allow the filesystem to