linux-kernel - [PATCH 23/24] GFS2: Fix locking issue mounting gfs2meta fs

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]

Message-Id: <1244622665-7470-24-git-send-email-swhiteho@redhat.com>
Date:	Wed, 10 Jun 2009 09:31:04 +0100
From:	Steven Whitehouse <swhiteho@...hat.com>
To:	linux-kernel@...r.kernel.org, cluster-devel@...hat.com
Cc:	Steven Whitehouse <swhiteho@...hat.com>,
	Christoph Hellwig <hch@...radead.org>
Subject: [PATCH 23/24] GFS2: Fix locking issue mounting gfs2meta fs

This patch uses sget() to get a reference to the
existing gfs2 sb when mouting the gfs2meta filesystem
(in fact thats just another mount of the gfs2
filesystem with a different root and this interface
is for backward compatibility).

Signed-off-by: Steven Whitehouse <swhiteho@...hat.com>
Reported-by: Benjamin Marzinski <bmarzins@...hat.com>
Tested-by: Benjamin Marzinski <bmarzins@...hat.com>
Cc: Christoph Hellwig <hch@...radead.org>

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 2cd1164..9da161c 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1273,9 +1273,20 @@ static int gfs2_get_sb(struct file_system_type *fs_type, int flags,
 	return get_sb_bdev(fs_type, flags, dev_name, data, fill_super, mnt);
 }
 
+static int test_meta_super(struct super_block *s, void *ptr)
+{
+	struct block_device *bdev = ptr;
+	return (bdev == s->s_bdev);
+}
+
+static int set_meta_super(struct super_block *s, void *ptr)
+{
+	return -EINVAL;
+}
+
 static struct super_block *get_gfs2_sb(const char *dev_name)
 {
-	struct super_block *sb;
+	struct super_block *s;
 	struct path path;
 	int error;
 
@@ -1283,30 +1294,27 @@ static struct super_block *get_gfs2_sb(const char *dev_name)
 	if (error) {
 		printk(KERN_WARNING "GFS2: path_lookup on %s returned error %d\n",
 		       dev_name, error);
-		return NULL;
+		return ERR_PTR(-ENOENT);
 	}
-	sb = path.dentry->d_inode->i_sb;
-	if (sb && (sb->s_type == &gfs2_fs_type))
-		atomic_inc(&sb->s_active);
-	else
-		sb = NULL;
+	s = sget(&gfs2_fs_type, test_meta_super, set_meta_super,
+		 path.dentry->d_inode->i_sb->s_bdev);
 	path_put(&path);
-	return sb;
+	return s;
 }
 
 static int gfs2_get_sb_meta(struct file_system_type *fs_type, int flags,
 			    const char *dev_name, void *data, struct vfsmount *mnt)
 {
-	struct super_block *sb = NULL;
+	struct super_block *s;
 	struct gfs2_sbd *sdp;
 
-	sb = get_gfs2_sb(dev_name);
-	if (!sb) {
+	s = get_gfs2_sb(dev_name);
+	if (IS_ERR(s)) {
 		printk(KERN_WARNING "GFS2: gfs2 mount does not exist\n");
-		return -ENOENT;
+		return PTR_ERR(s);
 	}
-	sdp = sb->s_fs_info;
-	mnt->mnt_sb = sb;
+	sdp = s->s_fs_info;
+	mnt->mnt_sb = s;
 	mnt->mnt_root = dget(sdp->sd_master_dir);
 	return 0;
 }
-- 
1.6.0.6

--
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/