* 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/module.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>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/pagevec.h>
+#include <linux/cleancache.h>
/*
* I/O completion handler for multipage BIOs.
* 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;
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);
-
- if (!uptodate){
- SetPageError(page);
- if (page->mapping)
- set_bit(AS_EIO, &page->mapping->flags);
+ if (bio_data_dir(bio) == READ) {
+ if (uptodate) {
+ SetPageUptodate(page);
+ } else {
+ ClearPageUptodate(page);
+ SetPageError(page);
+ }
+ unlock_page(page);
+ } else { /* bio_data_dir(bio) == WRITE */
+ if (!uptodate) {
+ SetPageError(page);
+ if (page->mapping)
+ set_bit(AS_EIO, &page->mapping->flags);
+ }
+ end_page_writeback(page);
}
- 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;
}
first_hole = page_block;
page_block++;
block_in_file++;
- clear_buffer_mapped(map_bh);
continue;
}
}
if (first_hole != blocks_per_page) {
- zero_user_page(page, first_hole << blkbits,
- PAGE_CACHE_SIZE - (first_hole << blkbits),
- KM_USER0);
+ zero_user_segment(page, first_hole << blkbits, PAGE_CACHE_SIZE);
if (first_hole == 0) {
SetPageUptodate(page);
unlock_page(page);
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?
*/
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];
}
/**
- * mpage_readpages - populate an address space with some pages, and
- * start reads against them.
- *
+ * mpage_readpages - populate an address space with some pages & start reads against them
* @mapping: the address_space
* @pages: The address of a list_head which contains the target pages. These
* pages have their ->index populated and are otherwise uninitialised.
- *
* The page at @pages->prev has the lowest file offset, and reads should be
* issued in @pages->prev to @pages->next order.
- *
* @nr_pages: The number of pages at *@pages
* @get_block: The filesystem's block mapper function.
*
* So an mpage read of the first 16 blocks of an ext2 file will cause I/O to be
* submitted in the following order:
* 12 0 1 2 3 4 5 6 7 8 9 10 11 13 14 15 16
+ *
* because the indirect block has to be read to get the mappings of blocks
* 13,14,15,16. Obviously, this impacts performance.
*
struct bio *bio = NULL;
unsigned page_idx;
sector_t last_block_in_bio = 0;
- struct pagevec lru_pvec;
struct buffer_head map_bh;
unsigned long first_logical_block = 0;
+ struct blk_plug plug;
- clear_buffer_mapped(&map_bh);
- pagevec_init(&lru_pvec, 0);
+ blk_start_plug(&plug);
+
+ 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);
prefetchw(&page->flags);
list_del(&page->lru);
- if (!add_to_page_cache(page, mapping,
+ if (!add_to_page_cache_lru(page, mapping,
page->index, GFP_KERNEL)) {
bio = do_mpage_readpage(bio, page,
nr_pages - page_idx,
&last_block_in_bio, &map_bh,
&first_logical_block,
get_block);
- if (!pagevec_add(&lru_pvec, page))
- __pagevec_lru_add(&lru_pvec);
- } else {
- page_cache_release(page);
}
+ page_cache_release(page);
}
- pagevec_lru_add(&lru_pvec);
BUG_ON(!list_empty(pages));
if (bio)
mpage_bio_submit(READ, bio);
+ blk_finish_plug(&plug);
return 0;
}
EXPORT_SYMBOL(mpage_readpages);
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)
* 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;
};
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;
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
if (page->index > end_index || !offset)
goto confused;
- zero_user_page(page, offset, PAGE_CACHE_SIZE - offset,
- KM_USER0);
+ zero_user_segment(page, offset, PAGE_CACHE_SIZE);
}
/*
}
/**
- * mpage_writepages - walk the list of dirty pages of the given
- * address space and writepage() all of them.
- *
+ * mpage_writepages - walk the list of dirty pages of the given address space & writepage() all of them
* @mapping: address space structure to write
* @wbc: subtract the number of written pages from *@wbc->nr_to_write
* @get_block: the filesystem's block mapper function.
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 {
if (mpd.bio)
mpage_bio_submit(WRITE, mpd.bio);
}
+ blk_finish_plug(&plug);
return ret;
}
EXPORT_SYMBOL(mpage_writepages);