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Commit 3ab2fb5a authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Add readpages support 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 856bf3e5

fs/btrfs/extent_map.c

+63 −7
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/swap.h>

#include <linux/version.h>

#include <linux/writeback.h>

#include <linux/pagevec.h>

#include "extent_map.h"



/* temporary define until extent_map moves out of btrfs */
@@ -1503,7 +1504,7 @@ static int submit_extent_page(int rw, struct extent_map_tree *tree, 
			      size_t size, unsigned long offset,

			      struct block_device *bdev,

			      struct bio **bio_ret,

			      int max_pages,

			      unsigned long max_pages,

			      bio_end_io_t end_io_func)

{

	int ret = 0;
@@ -1520,7 +1521,7 @@ static int submit_extent_page(int rw, struct extent_map_tree *tree, 
			return 0;

		}

	}

	nr = min(max_pages, bio_get_nr_vecs(bdev));

	nr = min_t(int, max_pages, bio_get_nr_vecs(bdev));

	bio = extent_bio_alloc(bdev, sector, nr, GFP_NOFS | __GFP_HIGH);

	if (!bio) {

		printk("failed to allocate bio nr %d\n", nr);
@@ -1552,8 +1553,10 @@ void set_page_extent_mapped(struct page *page) 
 * into the tree that are removed when the IO is done (by the end_io

 * handlers)

 */

int extent_read_full_page(struct extent_map_tree *tree, struct page *page,

			  get_extent_t *get_extent)

static int __extent_read_full_page(struct extent_map_tree *tree,

				   struct page *page,

				   get_extent_t *get_extent,

				   struct bio **bio)

{

	struct inode *inode = page->mapping->host;

	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
@@ -1631,9 +1634,11 @@ int extent_read_full_page(struct extent_map_tree *tree, struct page *page, 
							  cur + iosize - 1);

		}

		if (!ret) {

			unsigned long nr = (last_byte >> PAGE_CACHE_SHIFT) + 1;

			nr -= page->index;

			ret = submit_extent_page(READ, tree, page,

					 sector, iosize, page_offset,

						 bdev, NULL, 1,

					 bdev, bio, nr,

					 end_bio_extent_readpage);

		}

		if (ret)
@@ -1649,6 +1654,18 @@ int extent_read_full_page(struct extent_map_tree *tree, struct page *page, 
	}

	return 0;

}



int extent_read_full_page(struct extent_map_tree *tree, struct page *page,

			    get_extent_t *get_extent)

{

	struct bio *bio = NULL;

	int ret;



	ret = __extent_read_full_page(tree, page, get_extent, &bio);

	if (bio)

		submit_one_bio(READ, bio);

	return ret;

}

EXPORT_SYMBOL(extent_read_full_page);



/*
@@ -1836,6 +1853,45 @@ int extent_writepages(struct extent_map_tree *tree, 
}

EXPORT_SYMBOL(extent_writepages);



int extent_readpages(struct extent_map_tree *tree,

		     struct address_space *mapping,

		     struct list_head *pages, unsigned nr_pages,

		     get_extent_t get_extent)

{

	struct bio *bio = NULL;

	unsigned page_idx;

	struct pagevec pvec;



	pagevec_init(&pvec, 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);

		/*

		 * what we want to do here is call add_to_page_cache_lru,

		 * but that isn't exported, so we reproduce it here

		 */

		if (!add_to_page_cache(page, mapping,

					page->index, GFP_KERNEL)) {



			/* open coding of lru_cache_add, also not exported */

			page_cache_get(page);

			if (!pagevec_add(&pvec, page))

				__pagevec_lru_add(&pvec);

			__extent_read_full_page(tree, page, get_extent, &bio);

		}

		page_cache_release(page);

	}

	if (pagevec_count(&pvec))

		__pagevec_lru_add(&pvec);

	BUG_ON(!list_empty(pages));

	if (bio)

		submit_one_bio(READ, bio);

	return 0;

}

EXPORT_SYMBOL(extent_readpages);



/*

 * basic invalidatepage code, this waits on any locked or writeback

 * ranges corresponding to the page, and then deletes any extent state

fs/btrfs/extent_map.h

+4 −0
Original line number Diff line number Diff line
@@ -140,6 +140,10 @@ int extent_writepages(struct extent_map_tree *tree, 
		      struct address_space *mapping,

		      get_extent_t *get_extent,

		      struct writeback_control *wbc);

int extent_readpages(struct extent_map_tree *tree,

		     struct address_space *mapping,

		     struct list_head *pages, unsigned nr_pages,

		     get_extent_t get_extent);

int extent_prepare_write(struct extent_map_tree *tree,

			 struct inode *inode, struct page *page,

			 unsigned from, unsigned to, get_extent_t *get_extent);

fs/btrfs/inode.c

+11 −1
Original line number Diff line number Diff line
@@ -1748,7 +1748,6 @@ static int btrfs_writepage(struct page *page, struct writeback_control *wbc) 
	return extent_write_full_page(tree, page, btrfs_get_extent, wbc);

}





static int btrfs_writepages(struct address_space *mapping,

			    struct writeback_control *wbc)

{
@@ -1757,6 +1756,16 @@ static int btrfs_writepages(struct address_space *mapping, 
	return extent_writepages(tree, mapping, btrfs_get_extent, wbc);

}



static int

btrfs_readpages(struct file *file, struct address_space *mapping,

		struct list_head *pages, unsigned nr_pages)

{

	struct extent_map_tree *tree;

	tree = &BTRFS_I(mapping->host)->extent_tree;

	return extent_readpages(tree, mapping, pages, nr_pages,

				btrfs_get_extent);

}



static int btrfs_releasepage(struct page *page, gfp_t unused_gfp_flags)

{

	struct extent_map_tree *tree;
@@ -2537,6 +2546,7 @@ static struct address_space_operations btrfs_aops = { 
	.readpage	= btrfs_readpage,

	.writepage	= btrfs_writepage,

	.writepages	= btrfs_writepages,

	.readpages	= btrfs_readpages,

	.sync_page	= block_sync_page,

	.prepare_write	= btrfs_prepare_write,

	.commit_write	= btrfs_commit_write,