linux-kernel - [PATCH 03/14] fuse: Prepare to handle short reads

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20121116170548.3196.50962.stgit@maximpc.sw.ru>
Date:	Fri, 16 Nov 2012 21:06:55 +0400
From:	Maxim Patlasov <mpatlasov@...allels.com>
To:	miklos@...redi.hu
Cc:	dev@...allels.com, fuse-devel@...ts.sourceforge.net,
	linux-kernel@...r.kernel.org, jbottomley@...allels.com,
	viro@...iv.linux.org.uk, linux-fsdevel@...r.kernel.org,
	xemul@...nvz.org
Subject: [PATCH 03/14] fuse: Prepare to handle short reads

A helper which gets called when read reports less bytes than was requested.
See patch #6 (trust kernel i_size only) for details.

Signed-off-by: Maxim Patlasov <MPatlasov@...allels.com>
Signed-off-by: Pavel Emelyanov <xemul@...nvz.org>
---
 fs/fuse/file.c |   21 +++++++++++++--------
 1 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index cd41b56..51804cf 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -538,6 +538,15 @@ 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 inode *inode = page->mapping->host;
@@ -573,18 +582,18 @@ static int fuse_readpage(struct file *file, struct page *page)
 	req->pages[0] = page;
 	num_read = fuse_send_read(req, file, 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_attr(inode); /* atime changed */
  out:
 	unlock_page(page);
@@ -607,13 +616,9 @@ 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_attr(inode); /* atime changed */
 	}
 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/