linux-ext4 - [PATCH 1/2] ext4: check if device support discard in FITRIM ioctl

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-next>] [day] [month] [year] [list]

Message-Id: <1297789585-5986-1-git-send-email-lczerner@redhat.com>
Date:	Tue, 15 Feb 2011 18:06:24 +0100
From:	Lukas Czerner <lczerner@...hat.com>
To:	linux-ext4@...r.kernel.org
Cc:	tytso@....edu, lczerner@...hat.com
Subject: [PATCH 1/2] ext4: check if device support discard in FITRIM ioctl

Right now we, are relying on the fact that when we attempt to actually do
the discard, blkdev_issue_discar() returns -EOPNOTSUPP and the user is
informed that the device does not support discard.

However, in the case where the we do not hit any suitable free extent to
trim in FITRIM code, it will finish without any error. This is very
confusing, because it seems that FITRIM was successful even though the
device does not actually supports discard.

Solution: Check for the discard support before attempt to search for
free extents.

Signed-off-by: Lukas Czerner <lczerner@...hat.com>
---
 fs/ext4/ioctl.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index eb3bc2f..25ba7c7 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -334,12 +334,16 @@ mext_out:
 	case FITRIM:
 	{
 		struct super_block *sb = inode->i_sb;
+		struct request_queue *q = bdev_get_queue(sb->s_bdev);
 		struct fstrim_range range;
 		int ret = 0;

 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;

+		if (!blk_queue_discard(q))
+			return -EOPNOTSUPP;
+
 		if (copy_from_user(&range, (struct fstrim_range *)arg,
 		    sizeof(range)))
 			return -EFAULT;
-- 
1.7.4

--
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