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Btrfs: Add readpages support 

Signed-off-by: Chris Mason <chris.mason@oracle.com>
wifi-calibration
Chris Mason 2007-11-08 10:59:22 -05:00
parent 856bf3e592
commit 3ab2fb5a8c
3 changed files with 78 additions and 8 deletions
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70
fs/btrfs/extent_map.c
View File

@ -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;
@ -1631,10 +1634,12 @@ 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,
end_bio_extent_readpage);
sector, iosize, page_offset,
bdev, bio, nr,
end_bio_extent_readpage);
}
if (ret)
SetPageError(page);
@ -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

4
fs/btrfs/extent_map.h
View File

@ -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);

12
fs/btrfs/inode.c
View File

@ -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,