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?
>
>
> -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
>>
>
