On Mon, Apr 28, 2025 at 11:51:24AM +0000, Hans Holmberg wrote:
> On 28/04/2025 11:52, Carlos Maiolino wrote:
> > On Fri, Apr 25, 2025 at 08:52:53AM +0000, Hans Holmberg wrote:
> >> Allow read-only mounts on rtdevs and logdevs that are marked as
> >> read-only and make sure those mounts can't be remounted read-write.
> >>
> >> Signed-off-by: Hans Holmberg <hans.holmberg@xxxxxxx>
> >> ---
> >>
> >> I will post a couple of xfstests to add coverage for these cases.
> >>
> >> fs/xfs/xfs_super.c | 24 +++++++++++++++++++++---
> >> 1 file changed, 21 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> >> index b2dd0c0bf509..d7ac1654bc80 100644
> >> --- a/fs/xfs/xfs_super.c
> >> +++ b/fs/xfs/xfs_super.c
> >> @@ -380,10 +380,14 @@ xfs_blkdev_get(
> >> struct file **bdev_filep)
> >> {
> >> int error = 0;
> >> + blk_mode_t mode;
> >>
> >> - *bdev_filep = bdev_file_open_by_path(name,
> >> - BLK_OPEN_READ | BLK_OPEN_WRITE | BLK_OPEN_RESTRICT_WRITES,
> >> - mp->m_super, &fs_holder_ops);
> >> + mode = BLK_OPEN_READ | BLK_OPEN_RESTRICT_WRITES;
> >
> > Does BLK_OPEN_RESTRICT_WRITES makes sense without BLK_OPEN_WRITE?
> > Perhaps this should be OR'ed together with OPEN_WRITE below?
>
> BLK_OPEN_RESTRICT_WRITES disallows other writers to mounted devs, and I
> presume we want this for read-only mounts as well?
Thanks, it wasn't really clear to me what the purpose of RESTRICT_WRITES was,
thanks for the clarification, this looks good to me:
Reviewed-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
>
> >
> >
> > -Carlos
> >
> >> + if (!xfs_is_readonly(mp))
> >> + mode |= BLK_OPEN_WRITE;
> >
> >> +
> >> + *bdev_filep = bdev_file_open_by_path(name, mode,
> >> + mp->m_super, &fs_holder_ops);
> >> if (IS_ERR(*bdev_filep)) {
> >> error = PTR_ERR(*bdev_filep);
> >> *bdev_filep = NULL;
> >> @@ -1969,6 +1973,20 @@ xfs_remount_rw(
> >> struct xfs_sb *sbp = &mp->m_sb;
> >> int error;
> >>
> >> + if (mp->m_logdev_targp && mp->m_logdev_targp != mp->m_ddev_targp &&
> >> + bdev_read_only(mp->m_logdev_targp->bt_bdev)) {
> >> + xfs_warn(mp,
> >> + "ro->rw transition prohibited by read-only logdev");
> >> + return -EACCES;
> >> + }
> >> +
> >> + if (mp->m_rtdev_targp &&
> >> + bdev_read_only(mp->m_rtdev_targp->bt_bdev)) {
> >> + xfs_warn(mp,
> >> + "ro->rw transition prohibited by read-only rtdev");
> >> + return -EACCES;
> >> + }
> >> +
> >> if (xfs_has_norecovery(mp)) {
> >> xfs_warn(mp,
> >> "ro->rw transition prohibited on norecovery mount");
> >> --
> >> 2.34.1
> >>
> >
>
