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 for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20140501231400.31890.27469.stgit@birch.djwong.org>
Date:	Thu, 01 May 2014 16:14:00 -0700
From:	"Darrick J. Wong" <darrick.wong@...cle.com>
To:	tytso@....edu, darrick.wong@...cle.com
Cc:	linux-ext4@...r.kernel.org
Subject: [PATCH 15/37] mke2fs: set block_validity as a default mount option

The block_validity mount option spot-checks block allocations against
a bitmap of known group metadata blocks.  This helps us to prevent
self-inflicted catastrophic failures such as trying to "share"
critical metadata (think bitmaps) with file data, which usually
results in filesystem destruction.

In order to test the overhead of the mount option, I re-used the speed
tests in the metadata checksum testing script.  In short, the program
creates what looks like 15 copies of a kernel source tree, except that
it uses fallocate to strip out the overhead of writing the file data
so that we can focus on metadata overhead.  On a 64G RAM disk, the
overhead was generally about 0.9% and at most 1.6%.  On a 160G USB
disk, the overhead was about 0.8% and peaked at 1.2%.

When I changed the test to write out files instead of merely
fallocating space, the overhead was negligible.

Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
---
 misc/mke2fs.conf.in |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


diff --git a/misc/mke2fs.conf.in b/misc/mke2fs.conf.in
index 4c5dba7..de0250d 100644
--- a/misc/mke2fs.conf.in
+++ b/misc/mke2fs.conf.in
@@ -1,6 +1,6 @@
 [defaults]
 	base_features = sparse_super,filetype,resize_inode,dir_index,ext_attr
-	default_mntopts = acl,user_xattr
+	default_mntopts = acl,user_xattr,block_validity
 	enable_periodic_fsck = 0
 	blocksize = 4096
 	inode_size = 256

--
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

Powered by blists - more mailing lists