[PATCH] fuse: use asynchronous READ requests for readpages

This patch changes fuse_readpages() to send READ requests asynchronously. This makes it possible for userspace filesystems to utilize the kernel readahead logic instead of having to implement their own (resulting in double caching). Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] fuse: use asynchronous READ requests for readpages
This patch changes fuse_readpages() to send READ requests asynchronously. This makes it possible for userspace filesystems to utilize the kernel readahead logic instead of having to implement their own (resulting in double caching). Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Miklos Szeredi · Linus Torvalds
1 parent 361b1eb55e
Showing 1 changed file with 27 additions and 17 deletions Side-by-side Diff
fs/fuse/file.c
@@ -265,7 +265,7 @@
 	req->file = file;
 	req->in.numargs = 1;
 	req->in.args[0].size = sizeof(struct fuse_read_in);
-	req->in.args[0].value = &inarg;
+	req->in.args[0].value = inarg;
 	req->out.argpages = 1;
 	req->out.argvar = 1;
 	req->out.numargs = 1;
  
  
  
  
@@ -311,23 +311,35 @@
 	return err;
 }
  
-static int fuse_send_readpages(struct fuse_req *req, struct file *file,
-			       struct inode *inode)
+static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
 {
-	loff_t pos = page_offset(req->pages[0]);
-	size_t count = req->num_pages << PAGE_CACHE_SHIFT;
-	unsigned i;
-	req->out.page_zeroing = 1;
-	fuse_send_read(req, file, inode, pos, count);
+	int i;
+
+	fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */
+
 	for (i = 0; i < req->num_pages; i++) {
 		struct page *page = req->pages[i];
 		if (!req->out.h.error)
 			SetPageUptodate(page);
+		else
+			SetPageError(page);
 		unlock_page(page);
 	}
-	return req->out.h.error;
+	fuse_put_request(fc, req);
 }
  
+static void fuse_send_readpages(struct fuse_req *req, struct file *file,
+				struct inode *inode)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	loff_t pos = page_offset(req->pages[0]);
+	size_t count = req->num_pages << PAGE_CACHE_SHIFT;
+	req->out.page_zeroing = 1;
+	req->end = fuse_readpages_end;
+	fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
+	request_send_background(fc, req);
+}
+
 struct fuse_readpages_data {
 	struct fuse_req *req;
 	struct file *file;
  
  
@@ -345,12 +357,12 @@
 	    (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
 	     (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
 	     req->pages[req->num_pages - 1]->index + 1 != page->index)) {
-		int err = fuse_send_readpages(req, data->file, inode);
-		if (err) {
+		fuse_send_readpages(req, data->file, inode);
+		data->req = req = fuse_get_request(fc);
+		if (!req) {
 			unlock_page(page);
-			return err;
+			return -EINTR;
 		}
-		fuse_reset_request(req);
 	}
 	req->pages[req->num_pages] = page;
 	req->num_pages ++;
@@ -375,10 +387,8 @@
 		return -EINTR;
  
 	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
-	if (!err && data.req->num_pages)
-		err = fuse_send_readpages(data.req, file, inode);
-	fuse_put_request(fc, data.req);
-	fuse_invalidate_attr(inode); /* atime changed */
+	if (!err)
+		fuse_send_readpages(data.req, file, inode);
 	return err;
 }
...	...	@@ -265,7 +265,7 @@
265	265	req->file = file;
266	266	req->in.numargs = 1;
267	267	req->in.args[0].size = sizeof(struct fuse_read_in);
268		- req->in.args[0].value = &inarg;
	268	+ req->in.args[0].value = inarg;
269	269	req->out.argpages = 1;
270	270	req->out.argvar = 1;
271	271	req->out.numargs = 1;
272	272
273	273
274	274
275	275
...	...	@@ -311,23 +311,35 @@
311	311	return err;
312	312	}
313	313
314		-static int fuse_send_readpages(struct fuse_req req, struct file file,
315		- struct inode *inode)
	314	+static void fuse_readpages_end(struct fuse_conn fc, struct fuse_req req)
316	315	{
317		- loff_t pos = page_offset(req->pages[0]);
318		- size_t count = req->num_pages << PAGE_CACHE_SHIFT;
319		- unsigned i;
320		- req->out.page_zeroing = 1;
321		- fuse_send_read(req, file, inode, pos, count);
	316	+ int i;
	317	+
	318	+ fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */
	319	+
322	320	for (i = 0; i < req->num_pages; i++) {
323	321	struct page *page = req->pages[i];
324	322	if (!req->out.h.error)
325	323	SetPageUptodate(page);
	324	+ else
	325	+ SetPageError(page);
326	326	unlock_page(page);
327	327	}
328		- return req->out.h.error;
	328	+ fuse_put_request(fc, req);
329	329	}
330	330
	331	+static void fuse_send_readpages(struct fuse_req req, struct file file,
	332	+ struct inode *inode)
	333	+{
	334	+ struct fuse_conn *fc = get_fuse_conn(inode);
	335	+ loff_t pos = page_offset(req->pages[0]);
	336	+ size_t count = req->num_pages << PAGE_CACHE_SHIFT;
	337	+ req->out.page_zeroing = 1;
	338	+ req->end = fuse_readpages_end;
	339	+ fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
	340	+ request_send_background(fc, req);
	341	+}
	342	+
331	343	struct fuse_readpages_data {
332	344	struct fuse_req *req;
333	345	struct file *file;
334	346
335	347
...	...	@@ -345,12 +357,12 @@
345	357	(req->num_pages == FUSE_MAX_PAGES_PER_REQ \|\|
346	358	(req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read \|\|
347	359	req->pages[req->num_pages - 1]->index + 1 != page->index)) {
348		- int err = fuse_send_readpages(req, data->file, inode);
349		- if (err) {
	360	+ fuse_send_readpages(req, data->file, inode);
	361	+ data->req = req = fuse_get_request(fc);
	362	+ if (!req) {
350	363	unlock_page(page);
351		- return err;
	364	+ return -EINTR;
352	365	}
353		- fuse_reset_request(req);
354	366	}
355	367	req->pages[req->num_pages] = page;
356	368	req->num_pages ++;
...	...	@@ -375,10 +387,8 @@
375	387	return -EINTR;
376	388
377	389	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
378		- if (!err && data.req->num_pages)
379		- err = fuse_send_readpages(data.req, file, inode);
380		- fuse_put_request(fc, data.req);
381		- fuse_invalidate_attr(inode); /* atime changed */
	390	+ if (!err)
	391	+ fuse_send_readpages(data.req, file, inode);
382	392	return err;
383	393	}
384	394