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Commit 91b467e0 authored by David Howells's avatar David Howells
Browse files

afs: Make afs_readpages() fetch data in bulk



Make afs_readpages() use afs_vnode_fetch_data()'s new ability to take a
list of pages and do a bulk fetch.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 196ee9cd
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+129 −2
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/gfp.h>
#include <linux/task_io_accounting_ops.h>
#include "internal.h"

static int afs_readpage(struct file *file, struct page *page);
@@ -261,6 +262,129 @@ static int afs_readpage(struct file *file, struct page *page)
	return ret;
}

/*
 * Make pages available as they're filled.
 */
static void afs_readpages_page_done(struct afs_call *call, struct afs_read *req)
{
	struct afs_vnode *vnode = call->reply;
	struct page *page = req->pages[req->index];

	req->pages[req->index] = NULL;
	SetPageUptodate(page);

	/* send the page to the cache */
#ifdef CONFIG_AFS_FSCACHE
	if (PageFsCache(page) &&
	    fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
		fscache_uncache_page(vnode->cache, page);
		BUG_ON(PageFsCache(page));
	}
#endif
	unlock_page(page);
	put_page(page);
}

/*
 * Read a contiguous set of pages.
 */
static int afs_readpages_one(struct file *file, struct address_space *mapping,
			     struct list_head *pages)
{
	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
	struct afs_read *req;
	struct list_head *p;
	struct page *first, *page;
	struct key *key = file->private_data;
	pgoff_t index;
	int ret, n, i;

	/* Count the number of contiguous pages at the front of the list.  Note
	 * that the list goes prev-wards rather than next-wards.
	 */
	first = list_entry(pages->prev, struct page, lru);
	index = first->index + 1;
	n = 1;
	for (p = first->lru.prev; p != pages; p = p->prev) {
		page = list_entry(p, struct page, lru);
		if (page->index != index)
			break;
		index++;
		n++;
	}

	req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *) * n,
		      GFP_NOFS);
	if (!req)
		return -ENOMEM;

	atomic_set(&req->usage, 1);
	req->page_done = afs_readpages_page_done;
	req->pos = first->index;
	req->pos <<= PAGE_SHIFT;

	/* Transfer the pages to the request.  We add them in until one fails
	 * to add to the LRU and then we stop (as that'll make a hole in the
	 * contiguous run.
	 *
	 * Note that it's possible for the file size to change whilst we're
	 * doing this, but we rely on the server returning less than we asked
	 * for if the file shrank.  We also rely on this to deal with a partial
	 * page at the end of the file.
	 */
	do {
		page = list_entry(pages->prev, struct page, lru);
		list_del(&page->lru);
		index = page->index;
		if (add_to_page_cache_lru(page, mapping, index,
					  readahead_gfp_mask(mapping))) {
#ifdef CONFIG_AFS_FSCACHE
			fscache_uncache_page(vnode->cache, page);
#endif
			put_page(page);
			break;
		}

		req->pages[req->nr_pages++] = page;
		req->len += PAGE_SIZE;
	} while (req->nr_pages < n);

	if (req->nr_pages == 0) {
		kfree(req);
		return 0;
	}

	ret = afs_vnode_fetch_data(vnode, key, req);
	if (ret < 0)
		goto error;

	task_io_account_read(PAGE_SIZE * req->nr_pages);
	afs_put_read(req);
	return 0;

error:
	if (ret == -ENOENT) {
		_debug("got NOENT from server"
		       " - marking file deleted and stale");
		set_bit(AFS_VNODE_DELETED, &vnode->flags);
		ret = -ESTALE;
	}

	for (i = 0; i < req->nr_pages; i++) {
		page = req->pages[i];
		if (page) {
#ifdef CONFIG_AFS_FSCACHE
			fscache_uncache_page(vnode->cache, page);
#endif
			SetPageError(page);
			unlock_page(page);
		}
	}

	afs_put_read(req);
	return ret;
}

/*
 * read a set of pages
 */
@@ -314,8 +438,11 @@ static int afs_readpages(struct file *file, struct address_space *mapping,
		return ret;
	}

	/* load the missing pages from the network */
	ret = read_cache_pages(mapping, pages, afs_page_filler, key);
	while (!list_empty(pages)) {
		ret = afs_readpages_one(file, mapping, pages);
		if (ret < 0)
			break;
	}

	_leave(" = %d [netting]", ret);
	return ret;
+1 −0
Original line number Diff line number Diff line
@@ -106,6 +106,7 @@ struct afs_volume *afs_volume_lookup(struct afs_mount_params *params)
	volume->cell		= params->cell;
	volume->vid		= vlocation->vldb.vid[params->type];

	volume->bdi.ra_pages	= VM_MAX_READAHEAD*1024/PAGE_SIZE; 
	ret = bdi_setup_and_register(&volume->bdi, "afs");
	if (ret)
		goto error_bdi;