linux-ext4 - [PATCH] ext4: Don't allow nonextenst mount option for large file system.

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: <1214844775-14881-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
Date:	Mon, 30 Jun 2008 22:22:55 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	cmm@...ibm.com, tytso@....edu, sandeen@...hat.com
Cc:	linux-ext4@...r.kernel.org,
	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Subject: [PATCH] ext4: Don't allow nonextenst mount option for large file system.

The block mapped inode format can address only blocks within
2**32. So with file system larger than 2**32 don't allow
noextents mount option.  There are multiple issues that need
to addressed in the long run.

a) When e2fsprogs support resizing an already existing  ext3
file system to greater than 2**32 we need to add support to block
allocator to handle growing already existing block  mapped inode
so that blocks allocated for them fall within 2**32

b) When we do that we should enable mounting  larger file system
with -o noextents mount option.

Till them we fail mount of large file systems with -o noextents.


Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
---
 fs/ext4/super.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4e104dd..2bf9cdd 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1004,6 +1004,7 @@ static int parse_options (char *options, struct super_block *sb,
 	int qtype, qfmt;
 	char *qname;
 #endif
+	ext4_fsblk_t last_block;
 
 	if (!options)
 		return 1;
@@ -1326,6 +1327,20 @@ static int parse_options (char *options, struct super_block *sb,
 			set_opt (sbi->s_mount_opt, EXTENTS);
 			break;
 		case Opt_noextents:
+			/*
+			 * When e2fsprogs support resizing an already existing
+			 * ext3 file system to greater than 2**32 we need to
+			 * add support to block allocator to handle growing
+			 * already existing block  mapped inode so that blocks
+			 * allocated for them fall within 2**32
+			 */
+			last_block = ext4_blocks_count(sbi->s_es) - 1;
+			if (last_block  > 0xffffffffULL) {
+				printk(KERN_ERR "EXT4-fs: Filesystem too "
+						"large to mount with "
+						"-o noextents options\n");
+				return 0;
+			}
 			clear_opt (sbi->s_mount_opt, EXTENTS);
 			break;
 		case Opt_i_version:
-- 
1.5.6.1.102.g8e69d.dirty

--
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