Re: [PATCH] use proper mnt_want_write calls for handle ioctls

Christoph Hellwig
2008-09-29T07:41:06Z

ping^2?

On Fri, Sep 12, 2008 at 10:44:31AM +0200, Christoph Hellwig wrote:
> ping? Without this patch the CVS tree won't properly work with
> read-only bind mounts.
>
> On Thu, Aug 14, 2008 at 10:39:52PM +0200, Christoph Hellwig wrote:
> > Since 2.6.26 all writes to filesystems need to be enclosed by a
> > mnt_want_write / mnt_drop_write pair instead of checking for IS_RDONLY.
> >
> > XFs was updated for this in mainline but the changes to xfs_ioctl.c
> > were never megred back into the CVS tree.
> >
> > The original commit introducing this was:
> >
> > commit 42a74f206b914db13ee1f5ae932dcd91a77c8579
> > Author: Dave Hansen <haveblue@us.ibm.com>
> > Date: Fri Feb 15 14:37:46 2008 -0800
> >
> > [PATCH] r/o bind mounts: elevate write count for ioctls()
> >
> > Index: linux-2.6-xfs/fs/xfs/linux-2.6/xfs_ioctl.c
> > ===================================================================
> > --- linux-2.6-xfs.orig/fs/xfs/linux-2.6/xfs_ioctl.c 2008-08-14 14:54:53.000000000 -0300
> > +++ linux-2.6-xfs/fs/xfs/linux-2.6/xfs_ioctl.c 2008-08-14 15:15:49.000000000 -0300
> > @@ -543,8 +543,6 @@ xfs_attrmulti_attr_set(
> > char *kbuf;
> > int error = EFAULT;
> >
> > - if (IS_RDONLY(inode))
> > - return -EROFS;
> > if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
> > return EPERM;
> > if (len > XATTR_SIZE_MAX)
> > @@ -570,8 +568,6 @@ xfs_attrmulti_attr_remove(
> > char *name,
> > __uint32_t flags)
> > {
> > - if (IS_RDONLY(inode))
> > - return -EROFS;
> > if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
> > return EPERM;
> > return xfs_attr_remove(XFS_I(inode), name, flags);
> > @@ -581,6 +577,7 @@ STATIC int
> > xfs_attrmulti_by_handle(
> > xfs_mount_t *mp,
> > void __user *arg,
> > + struct file *parfilp,
> > struct inode *parinode)
> > {
> > int error;
> > @@ -634,13 +631,21 @@ xfs_attrmulti_by_handle(
> > &ops[i].am_length, ops[i].am_flags);
> > break;
> > case ATTR_OP_SET:
> > + ops[i].am_error = mnt_want_write(parfilp->f_path.mnt);
> > + if (ops[i].am_error)
> > + break;
> > ops[i].am_error = xfs_attrmulti_attr_set(inode,
> > attr_name, ops[i].am_attrvalue,
> > ops[i].am_length, ops[i].am_flags);
> > + mnt_drop_write(parfilp->f_path.mnt);
> > break;
> > case ATTR_OP_REMOVE:
> > + ops[i].am_error = mnt_want_write(parfilp->f_path.mnt);
> > + if (ops[i].am_error)
> > + break;
> > ops[i].am_error = xfs_attrmulti_attr_remove(inode,
> > attr_name, ops[i].am_flags);
> > + mnt_drop_write(parfilp->f_path.mnt);
> > break;
> > default:
> > ops[i].am_error = EINVAL;
> > @@ -1431,7 +1436,7 @@ xfs_ioctl(
> > return xfs_attrlist_by_handle(mp, arg, inode);
> >
> > case XFS_IOC_ATTRMULTI_BY_HANDLE:
> > - return xfs_attrmulti_by_handle(mp, arg, inode);
> > + return xfs_attrmulti_by_handle(mp, arg, filp, inode);
> >
> > case XFS_IOC_SWAPEXT: {
> > error = xfs_swapext((struct xfs_swapext __user *)arg);
> ---end quoted text---