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Commit db50b96c authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
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[PATCH] FUSE - readpages operation 



This patch adds readpages support to FUSE.

With the help of the readpages() operation multiple reads are bundled
together and sent as a single request to userspace.  This can improve
reading performace.

Signed-off-by: default avatarMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 06663267

fs/fuse/file.c

+67 −0
Original line number Diff line number Diff line
@@ -227,6 +227,72 @@ static int fuse_readpage(struct file *file, struct page *page) 
	return err;

}



static int fuse_send_readpages(struct fuse_req *req, struct file *file,

			       struct inode *inode)

{

	loff_t pos = (loff_t) req->pages[0]->index << PAGE_CACHE_SHIFT;

	size_t count = req->num_pages << PAGE_CACHE_SHIFT;

	unsigned i;

	req->out.page_zeroing = 1;

	fuse_send_read(req, file, inode, pos, count);

	for (i = 0; i < req->num_pages; i++) {

		struct page *page = req->pages[i];

		if (!req->out.h.error)

			SetPageUptodate(page);

		unlock_page(page);

	}

	return req->out.h.error;

}



struct fuse_readpages_data {

	struct fuse_req *req;

	struct file *file;

	struct inode *inode;

};



static int fuse_readpages_fill(void *_data, struct page *page)

{

	struct fuse_readpages_data *data = _data;

	struct fuse_req *req = data->req;

	struct inode *inode = data->inode;

	struct fuse_conn *fc = get_fuse_conn(inode);



	if (req->num_pages &&

	    (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) {

			unlock_page(page);

			return err;

		}

		fuse_reset_request(req);

	}

	req->pages[req->num_pages] = page;

	req->num_pages ++;

	return 0;

}



static int fuse_readpages(struct file *file, struct address_space *mapping,

			  struct list_head *pages, unsigned nr_pages)

{

	struct inode *inode = mapping->host;

	struct fuse_conn *fc = get_fuse_conn(inode);

	struct fuse_readpages_data data;

	int err;

	data.file = file;

	data.inode = inode;

	data.req = fuse_get_request_nonint(fc);

	if (!data.req)

		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);

	return err;

}



static ssize_t fuse_send_write(struct fuse_req *req, struct file *file,

			       struct inode *inode, loff_t pos, size_t count)

{
@@ -331,6 +397,7 @@ static struct address_space_operations fuse_file_aops = { 
	.readpage	= fuse_readpage,

	.prepare_write	= fuse_prepare_write,

	.commit_write	= fuse_commit_write,

	.readpages	= fuse_readpages,

	.set_page_dirty	= fuse_set_page_dirty,

};

fs/fuse/fuse_i.h

+3 −0
Original line number Diff line number Diff line
@@ -201,6 +201,9 @@ struct fuse_conn { 
	/** The fuse mount flags for this mount */

	unsigned flags;



	/** Maximum read size */

	unsigned max_read;



	/** Readers of the connection are waiting on this */

	wait_queue_head_t waitq;

fs/fuse/inode.c

+15 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ struct fuse_mount_data { 
	unsigned rootmode;

	unsigned user_id;

	unsigned flags;

	unsigned max_read;

};



static struct inode *fuse_alloc_inode(struct super_block *sb)
@@ -250,6 +251,7 @@ enum { 
	OPT_DEFAULT_PERMISSIONS,

	OPT_ALLOW_OTHER,

	OPT_KERNEL_CACHE,

	OPT_MAX_READ,

	OPT_ERR

};
@@ -260,6 +262,7 @@ static match_table_t tokens = { 
	{OPT_DEFAULT_PERMISSIONS,	"default_permissions"},

	{OPT_ALLOW_OTHER,		"allow_other"},

	{OPT_KERNEL_CACHE,		"kernel_cache"},

	{OPT_MAX_READ,			"max_read=%u"},

	{OPT_ERR,			NULL}

};
@@ -268,6 +271,7 @@ static int parse_fuse_opt(char *opt, struct fuse_mount_data *d) 
	char *p;

	memset(d, 0, sizeof(struct fuse_mount_data));

	d->fd = -1;

	d->max_read = ~0;



	while ((p = strsep(&opt, ",")) != NULL) {

		int token;
@@ -308,6 +312,12 @@ static int parse_fuse_opt(char *opt, struct fuse_mount_data *d) 
			d->flags |= FUSE_KERNEL_CACHE;

			break;



		case OPT_MAX_READ:

			if (match_int(&args[0], &value))

				return 0;

			d->max_read = value;

			break;



		default:

			return 0;

		}
@@ -329,6 +339,8 @@ static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt) 
		seq_puts(m, ",allow_other");

	if (fc->flags & FUSE_KERNEL_CACHE)

		seq_puts(m, ",kernel_cache");

	if (fc->max_read != ~0)

		seq_printf(m, ",max_read=%u", fc->max_read);

	return 0;

}
@@ -453,6 +465,9 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent) 


	fc->flags = d.flags;

	fc->user_id = d.user_id;

	fc->max_read = d.max_read;

	if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages)

		fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE;



	err = -ENOMEM;

	root = get_root_inode(sb, d.rootmode);