Union mounts want to guarantee that the read-only layer is read-only - and stays read-only. Use the new superblock read-only user count. XXX - Put common code in loopback and regular mounts in a function Signed-off-by: Valerie Aurora <vaurora@xxxxxxxxxx> --- fs/namespace.c | 13 +++++++++++++ 1 files changed, 13 insertions(+), 0 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 0280e5b..505974a 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1111,6 +1111,11 @@ static int do_umount(struct vfsmount *mnt, int flags) spin_unlock(&vfsmount_lock); if (retval) security_sb_umount_busy(mnt); + /* If this was a union mount, we are no longer a read-only + * user on the underlying mount */ + if (mnt->mnt_flags & MNT_UNION) + mnt->mnt_parent->mnt_sb->s_readonly_users--; + up_write(&namespace_sem); release_mounts(&umount_list); return retval; @@ -1511,6 +1516,10 @@ static int do_loopback(struct path *path, char *old_name, int recurse, release_mounts(&umount_list); } + /* If this is a union mount, add ourselves to the readonly users */ + if (mnt_flags & MNT_UNION) + mnt->mnt_parent->mnt_sb->s_readonly_users++; + out: up_write(&namespace_sem); path_put(&old_path); @@ -1730,6 +1739,10 @@ int do_add_mount(struct vfsmount *newmnt, struct path *path, if ((err = graft_tree(newmnt, path))) goto unlock; + /* If this is a union mount, add ourselves to the readonly users */ + if (mnt_flags & MNT_UNION) + newmnt->mnt_parent->mnt_sb->s_readonly_users++; + if (fslist) /* add to the specified expiration list */ list_add_tail(&newmnt->mnt_expire, fslist); -- 1.6.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
