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Message-ID: <148372254415.8578.7711330270476665864.stgit@warthog.procyon.org.uk>
Date: Fri, 06 Jan 2017 17:09:04 +0000
From: David Howells <dhowells@...hat.com>
To: netdev@...r.kernel.org
Cc: dhowells@...hat.com, linux-afs@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: [PATCH net-next 2/2] 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: David Howells <dhowells@...hat.com>
---
fs/afs/file.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
fs/afs/volume.c | 1
2 files changed, 130 insertions(+), 2 deletions(-)
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 6c262ceef32d..82897a78abc7 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -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);
@@ -262,6 +263,129 @@ static int afs_readpage(struct file *file, struct page *page)
}
/*
+ * 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
*/
static int afs_readpages(struct file *file, struct address_space *mapping,
@@ -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;
diff --git a/fs/afs/volume.c b/fs/afs/volume.c
index d142a2449e65..546f9d01710b 100644
--- a/fs/afs/volume.c
+++ b/fs/afs/volume.c
@@ -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;
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