From: NeilBrown <neilb@suse.de>
Date: Sun, 20 Mar 2011 21:22:34 +0000 (+1100)
Subject: Mount: need to return the superblock with s_umount held.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=63fb64bfee93155611b130a042498b51e9838c47;p=LaFS.git

Mount: need to return the superblock with s_umount held.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/super.c b/super.c
index 591f2c2..dcc9f38 100644
--- a/super.c
+++ b/super.c
@@ -1077,6 +1077,7 @@ lafs_get_subset(struct file_system_type *fs_type,
 	    LAFSI(ino)->type != TypeDir)
 		goto out;
 	fs = fs_from_sb(sb);
+	down_write(&sb->s_umount);
 	mutex_lock(&ino->i_mutex);
 	err = 0;
 	if (LAFSI(ino)->type == TypeDir) {
@@ -1147,12 +1148,14 @@ lafs_get_subset(struct file_system_type *fs_type,
 	if (IS_ERR(root))
 		err = PTR_ERR(root);
 	else {
-		mnt->mnt_sb = fs->prime_sb;
+		mnt->mnt_sb = root->d_sb;
 		atomic_inc(&mnt->mnt_sb->s_active);
 		mnt->mnt_root = root;
 	}
 out_unlock:
 	mutex_unlock(&ino->i_mutex);
+	if (err)
+		up_write(&ino->i_sb->s_umount);
 out:
 	path_put(&nd.path);
 out_noput: