linux-kernel - [PATCH v3 4/6] fat: fallback to buffered write in case of fallocated region on direct IO

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>] [day] [month] [year] [list]

Message-Id: <1387953097-2794-1-git-send-email-linkinjeon@gmail.com>
Date:	Wed, 25 Dec 2013 15:31:37 +0900
From:	Namjae Jeon <linkinjeon@...il.com>
To:	hirofumi@...l.parknet.co.jp, akpm@...ux-foundation.org
Cc:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Namjae Jeon <linkinjeon@...il.com>,
	Namjae Jeon <namjae.jeon@...sung.com>,
	Amit Sahrawat <a.sahrawat@...sung.com>
Subject: [PATCH v3 4/6] fat: fallback to buffered write in case of fallocated region on direct IO

From: Namjae Jeon <namjae.jeon@...sung.com>

For normal cases of direct IO write, trying to seek to location greater
than file size, makes it fall back to buffered write to fill that region.
Similarly, in case for write in Fallocated region, make it fall
to buffered write.

Signed-off-by: Namjae Jeon <namjae.jeon@...sung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@...sung.com>
---
 fs/fat/inode.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 8415807..3636617 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -229,6 +229,13 @@ static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
 		loff_t size = offset + iov_length(iov, nr_segs);
 		if (MSDOS_I(inode)->mmu_private < size)
 			return 0;
+
+		/*
+		 * In case of writing in fallocated region, return 0 and
+		 * fallback to buffered write.
+		 */
+		if (MSDOS_I(inode)->i_disksize > MSDOS_I(inode)->mmu_private)
+			return 0;
 	}
 
 	/*
-- 
1.7.9.5

--
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/