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Commit a92adc82 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Miklos Szeredi
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fuse: Prepare to handle short reads 



A helper which gets called when read reports less bytes than was requested.
See patch "trust kernel i_size only" for details.

Signed-off-by: default avatarMaxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent 650b22b9

fs/fuse/file.c

+13 −8
Original line number Diff line number Diff line
@@ -671,6 +671,15 @@ static void fuse_read_update_size(struct inode *inode, loff_t size, 
	spin_unlock(&fc->lock);

}



static void fuse_short_read(struct fuse_req *req, struct inode *inode,

			    u64 attr_ver)

{

	size_t num_read = req->out.args[0].size;



	loff_t pos = page_offset(req->pages[0]) + num_read;

	fuse_read_update_size(inode, pos, attr_ver);

}



static int fuse_readpage(struct file *file, struct page *page)

{

	struct fuse_io_priv io = { .async = 0, .file = file };
@@ -708,18 +717,18 @@ static int fuse_readpage(struct file *file, struct page *page) 
	req->page_descs[0].length = count;

	num_read = fuse_send_read(req, &io, pos, count, NULL);

	err = req->out.h.error;

	fuse_put_request(fc, req);



	if (!err) {

		/*

		 * Short read means EOF.  If file size is larger, truncate it

		 */

		if (num_read < count)

			fuse_read_update_size(inode, pos + num_read, attr_ver);

			fuse_short_read(req, inode, attr_ver);



		SetPageUptodate(page);

	}



	fuse_put_request(fc, req);

	fuse_invalidate_atime(inode);

 out:

	unlock_page(page);
@@ -742,13 +751,9 @@ static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req) 
		/*

		 * Short read means EOF. If file size is larger, truncate it

		 */

		if (!req->out.h.error && num_read < count) {

			loff_t pos;

		if (!req->out.h.error && num_read < count)

			fuse_short_read(req, inode, req->misc.read.attr_ver);



			pos = page_offset(req->pages[0]) + num_read;

			fuse_read_update_size(inode, pos,

					      req->misc.read.attr_ver);

		}

		fuse_invalidate_atime(inode);

	}