1 files changed, 76 insertions, 73 deletions

diff --git a/fs/mpage.c b/fs/mpage.c
index 235e4d3873a..5f9ed622274 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -6,16 +6,17 @@
  * Contains functions related to preparing and submitting BIOs which contain
  * multiple pagecache pages.
  *
- * 15May2002	akpm@zip.com.au
+ * 15May2002	Andrew Morton
  *		Initial version
  * 27Jun2002	axboe@suse.de
  *		use bio_add_page() to build bio's just the right size
  */
 
 #include <linux/kernel.h>
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/mm.h>
 #include <linux/kdev_t.h>
+#include <linux/gfp.h>
 #include <linux/bio.h>
 #include <linux/fs.h>
 #include <linux/buffer_head.h>
@@ -26,6 +27,7 @@
 #include <linux/writeback.h>
 #include <linux/backing-dev.h>
 #include <linux/pagevec.h>
+#include <linux/cleancache.h>
 
 /*
  * I/O completion handler for multipage BIOs.
@@ -39,54 +41,22 @@
  * status of that page is hard.  See end_buffer_async_read() for the details.
  * There is no point in duplicating all that complexity.
  */
-static void mpage_end_io_read(struct bio *bio, int err)
+static void mpage_end_io(struct bio *bio, int err)
 {
-	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
-	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
+	struct bio_vec *bv;
+	int i;
 
-	do {
-		struct page *page = bvec->bv_page;
-
-		if (--bvec >= bio->bi_io_vec)
-			prefetchw(&bvec->bv_page->flags);
-
-		if (uptodate) {
-			SetPageUptodate(page);
-		} else {
-			ClearPageUptodate(page);
-			SetPageError(page);
-		}
-		unlock_page(page);
-	} while (bvec >= bio->bi_io_vec);
-	bio_put(bio);
-}
-
-static void mpage_end_io_write(struct bio *bio, int err)
-{
-	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
-	struct bio_vec *bvec = bio->bi_io_vec + bio->bi_vcnt - 1;
-
-	do {
-		struct page *page = bvec->bv_page;
-
-		if (--bvec >= bio->bi_io_vec)
-			prefetchw(&bvec->bv_page->flags);
+	bio_for_each_segment_all(bv, bio, i) {
+		struct page *page = bv->bv_page;
+		page_endio(page, bio_data_dir(bio), err);
+	}
 
-		if (!uptodate){
-			SetPageError(page);
-			if (page->mapping)
-				set_bit(AS_EIO, &page->mapping->flags);
-		}
-		end_page_writeback(page);
-	} while (bvec >= bio->bi_io_vec);
 	bio_put(bio);
 }
 
 static struct bio *mpage_bio_submit(int rw, struct bio *bio)
 {
-	bio->bi_end_io = mpage_end_io_read;
-	if (rw == WRITE)
-		bio->bi_end_io = mpage_end_io_write;
+	bio->bi_end_io = mpage_end_io;
 	submit_bio(rw, bio);
 	return NULL;
 }
@@ -107,7 +77,7 @@ mpage_alloc(struct block_device *bdev,
 
 	if (bio) {
 		bio->bi_bdev = bdev;
-		bio->bi_sector = first_sector;
+		bio->bi_iter.bi_sector = first_sector;
 	}
 	return bio;
 }
@@ -240,7 +210,6 @@ do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
 				first_hole = page_block;
 			page_block++;
 			block_in_file++;
-			clear_buffer_mapped(map_bh);
 			continue;
 		}
 
@@ -286,6 +255,12 @@ do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
 		SetPageMappedToDisk(page);
 	}
 
+	if (fully_mapped && blocks_per_page == 1 && !PageUptodate(page) &&
+	    cleancache_get_page(page) == 0) {
+		SetPageUptodate(page);
+		goto confused;
+	}
+
 	/*
 	 * This page will go to BIO.  Do we need to send this BIO off first?
 	 */
@@ -294,6 +269,11 @@ do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
 
 alloc_new:
 	if (bio == NULL) {
+		if (first_hole == blocks_per_page) {
+			if (!bdev_read_page(bdev, blocks[0] << (blkbits - 9),
+								page))
+				goto out;
+		}
 		bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
 			  	min_t(int, nr_pages, bio_get_nr_vecs(bdev)),
 				GFP_KERNEL);
@@ -307,7 +287,10 @@ alloc_new:
 		goto alloc_new;
 	}
 
-	if (buffer_boundary(map_bh) || (first_hole != blocks_per_page))
+	relative_block = block_in_file - *first_logical_block;
+	nblocks = map_bh->b_size >> blkbits;
+	if ((buffer_boundary(map_bh) && relative_block == nblocks) ||
+	    (first_hole != blocks_per_page))
 		bio = mpage_bio_submit(READ, bio);
 	else
 		*last_block_in_bio = blocks[blocks_per_page - 1];
@@ -377,7 +360,8 @@ mpage_readpages(struct address_space *mapping, struct list_head *pages,
 	struct buffer_head map_bh;
 	unsigned long first_logical_block = 0;
 
-	clear_buffer_mapped(&map_bh);
+	map_bh.b_state = 0;
+	map_bh.b_size = 0;
 	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 		struct page *page = list_entry(pages->prev, struct page, lru);
 
@@ -410,7 +394,8 @@ int mpage_readpage(struct page *page, get_block_t get_block)
 	struct buffer_head map_bh;
 	unsigned long first_logical_block = 0;
 
-	clear_buffer_mapped(&map_bh);
+	map_bh.b_state = 0;
+	map_bh.b_size = 0;
 	bio = do_mpage_readpage(bio, page, 1, &last_block_in_bio,
 			&map_bh, &first_logical_block, get_block);
 	if (bio)
@@ -435,6 +420,7 @@ EXPORT_SYMBOL(mpage_readpage);
  * written, so it can intelligently allocate a suitably-sized BIO.  For now,
  * just allocate full-size (16-page) BIOs.
  */
+
 struct mpage_data {
 	struct bio *bio;
 	sector_t last_block_in_bio;
@@ -442,8 +428,37 @@ struct mpage_data {
 	unsigned use_writepage;
 };
 
+/*
+ * We have our BIO, so we can now mark the buffers clean.  Make
+ * sure to only clean buffers which we know we'll be writing.
+ */
+static void clean_buffers(struct page *page, unsigned first_unmapped)
+{
+	unsigned buffer_counter = 0;
+	struct buffer_head *bh, *head;
+	if (!page_has_buffers(page))
+		return;
+	head = page_buffers(page);
+	bh = head;
+
+	do {
+		if (buffer_counter++ == first_unmapped)
+			break;
+		clear_buffer_dirty(bh);
+		bh = bh->b_this_page;
+	} while (bh != head);
+
+	/*
+	 * we cannot drop the bh if the page is not uptodate or a concurrent
+	 * readpage would fail to serialize with the bh and it would read from
+	 * disk before we reach the platter.
+	 */
+	if (buffer_heads_over_limit && PageUptodate(page))
+		try_to_free_buffers(page);
+}
+
 static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
-			     void *data)
+		      void *data)
 {
 	struct mpage_data *mpd = data;
 	struct bio *bio = mpd->bio;
@@ -556,7 +571,7 @@ page_is_mapped:
 	if (page->index >= end_index) {
 		/*
 		 * The page straddles i_size.  It must be zeroed out on each
-		 * and every writepage invokation because it may be mmapped.
+		 * and every writepage invocation because it may be mmapped.
 		 * "A file is mapped in multiples of the page size.  For a file
 		 * that is not a multiple of the page size, the remaining memory
 		 * is zeroed when mapped, and writes to that region are not
@@ -577,6 +592,13 @@ page_is_mapped:
 
 alloc_new:
 	if (bio == NULL) {
+		if (first_unmapped == blocks_per_page) {
+			if (!bdev_write_page(bdev, blocks[0] << (blkbits - 9),
+								page, wbc)) {
+				clean_buffers(page, first_unmapped);
+				goto out;
+			}
+		}
 		bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
 				bio_get_nr_vecs(bdev), GFP_NOFS|__GFP_HIGH);
 		if (bio == NULL)
@@ -594,30 +616,7 @@ alloc_new:
 		goto alloc_new;
 	}
 
-	/*
-	 * OK, we have our BIO, so we can now mark the buffers clean.  Make
-	 * sure to only clean buffers which we know we'll be writing.
-	 */
-	if (page_has_buffers(page)) {
-		struct buffer_head *head = page_buffers(page);
-		struct buffer_head *bh = head;
-		unsigned buffer_counter = 0;
-
-		do {
-			if (buffer_counter++ == first_unmapped)
-				break;
-			clear_buffer_dirty(bh);
-			bh = bh->b_this_page;
-		} while (bh != head);
-
-		/*
-		 * we cannot drop the bh if the page is not uptodate
-		 * or a concurrent readpage would fail to serialize with the bh
-		 * and it would read from disk before we reach the platter.
-		 */
-		if (buffer_heads_over_limit && PageUptodate(page))
-			try_to_free_buffers(page);
-	}
+	clean_buffers(page, first_unmapped);
 
 	BUG_ON(PageWriteback(page));
 	set_page_writeback(page);
@@ -675,8 +674,11 @@ int
 mpage_writepages(struct address_space *mapping,
 		struct writeback_control *wbc, get_block_t get_block)
 {
+	struct blk_plug plug;
 	int ret;
 
+	blk_start_plug(&plug);
+
 	if (!get_block)
 		ret = generic_writepages(mapping, wbc);
 	else {
@@ -691,6 +693,7 @@ mpage_writepages(struct address_space *mapping,
 		if (mpd.bio)
 			mpage_bio_submit(WRITE, mpd.bio);
 	}
+	blk_finish_plug(&plug);
 	return ret;
 }
 EXPORT_SYMBOL(mpage_writepages);