linux-ext4 - [PATCH 1/6] fs: add hole punching to fallocate

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]

Date:	Wed, 17 Nov 2010 20:46:15 -0500
From:	Josef Bacik <josef@...hat.com>
To:	david@...morbit.com, linux-kernel@...r.kernel.org,
	linux-btrfs@...r.kernel.org, linux-ext4@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, xfs@....sgi.com, cmm@...ibm.com,
	cluster-devel@...hat.com, joel.becker@...cle.com, jack@...e.cz
Subject: [PATCH 1/6] fs: add hole punching to fallocate

Hole punching has already been implemented by XFS and OCFS2, and has the
potential to be implemented on both BTRFS and EXT4 so we need a generic way to
get to this feature.  The simplest way in my mind is to add FALLOC_FL_PUNCH_HOLE
to fallocate() since it already looks like the normal fallocate() operation.
I've tested this patch with XFS and BTRFS to make sure XFS did what it's
supposed to do and that BTRFS failed like it was supposed to.  Thank you,

Signed-off-by: Josef Bacik <josef@...hat.com>
---
 fs/open.c              |    7 ++++++-
 include/linux/falloc.h |    1 +
 2 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/fs/open.c b/fs/open.c
index 4197b9e..5b6ef7e 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -223,7 +223,12 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 		return -EINVAL;
 
 	/* Return error if mode is not supported */
-	if (mode && !(mode & FALLOC_FL_KEEP_SIZE))
+	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+		return -EOPNOTSUPP;
+
+	/* Punch hole must have keep size set */
+	if ((mode & FALLOC_FL_PUNCH_HOLE) &&
+	    !(mode & FALLOC_FL_KEEP_SIZE))
 		return -EOPNOTSUPP;
 
 	if (!(file->f_mode & FMODE_WRITE))
diff --git a/include/linux/falloc.h b/include/linux/falloc.h
index 3c15510..73e0b62 100644
--- a/include/linux/falloc.h
+++ b/include/linux/falloc.h
@@ -2,6 +2,7 @@
 #define _FALLOC_H_
 
 #define FALLOC_FL_KEEP_SIZE	0x01 /* default is extend size */
+#define FALLOC_FL_PUNCH_HOLE	0x02 /* de-allocates range */
 
 #ifdef __KERNEL__
 
-- 
1.6.6.1

--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html