On 2020/11/30 21:13, Anand Jain wrote:
> On 28/11/20 2:44 am, David Sterba wrote:
>> On Wed, Nov 18, 2020 at 07:29:20PM +0800, Anand Jain wrote:
>>> On 10/11/20 7:26 pm, Naohiro Aota wrote:
>>>> This commit introduces the function btrfs_check_zoned_mode() to check if
>>>> ZONED flag is enabled on the file system and if the file system consists of
>>>> zoned devices with equal zone size.
>>>>
>>>> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx>
>>>> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
>>>> Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
>>>> Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
>>>> ---
>>>> fs/btrfs/ctree.h | 11 ++++++
>>>> fs/btrfs/dev-replace.c | 7 ++++
>>>> fs/btrfs/disk-io.c | 11 ++++++
>>>> fs/btrfs/super.c | 1 +
>>>> fs/btrfs/volumes.c | 5 +++
>>>> fs/btrfs/zoned.c | 81 ++++++++++++++++++++++++++++++++++++++++++
>>>> fs/btrfs/zoned.h | 26 ++++++++++++++
>>>> 7 files changed, 142 insertions(+)
>>>>
>>>> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
>>>> index aac3d6f4e35b..453f41ca024e 100644
>>>> --- a/fs/btrfs/ctree.h
>>>> +++ b/fs/btrfs/ctree.h
>>>> @@ -948,6 +948,12 @@ struct btrfs_fs_info {
>>>> /* Type of exclusive operation running */
>>>> unsigned long exclusive_operation;
>>>>
>>>> + /* Zone size when in ZONED mode */
>>>> + union {
>>>> + u64 zone_size;
>>>> + u64 zoned;
>>>> + };
>>>> +
>>>> #ifdef CONFIG_BTRFS_FS_REF_VERIFY
>>>> spinlock_t ref_verify_lock;
>>>> struct rb_root block_tree;
>>>> @@ -3595,4 +3601,9 @@ static inline int btrfs_is_testing(struct btrfs_fs_info *fs_info)
>>>> }
>>>> #endif
>>>>
>>>> +static inline bool btrfs_is_zoned(struct btrfs_fs_info *fs_info)
>>>> +{
>>>> + return fs_info->zoned != 0;
>>>> +}
>>>> +
>>>> #endif
>>>> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
>>>> index 6f6d77224c2b..db87f1aa604b 100644
>>>> --- a/fs/btrfs/dev-replace.c
>>>> +++ b/fs/btrfs/dev-replace.c
>>>> @@ -238,6 +238,13 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
>>>> return PTR_ERR(bdev);
>>>> }
>>>>
>>>> + if (!btrfs_check_device_zone_type(fs_info, bdev)) {
>>>> + btrfs_err(fs_info,
>>>> + "dev-replace: zoned type of target device mismatch with filesystem");
>>>> + ret = -EINVAL;
>>>> + goto error;
>>>> + }
>>>> +
>>>> sync_blockdev(bdev);
>>>>
>>>> list_for_each_entry(device, &fs_info->fs_devices->devices, dev_list) {
>>>
>>> I am not sure if it is done in some other patch. But we still have to
>>> check for
>>>
>>> (model == BLK_ZONED_HA && incompat_zoned))
>>
>> Do you really mean BLK_ZONED_HA, ie. host-aware (HA)?
>> btrfs_check_device_zone_type checks for _HM.
>
>
> Still confusing to me. The below function, which is part of this
> patch, says we don't support BLK_ZONED_HM. So does it mean we
> allow BLK_ZONED_HA only?
>
> +static inline bool btrfs_check_device_zone_type(struct btrfs_fs_info
> *fs_info,
> + struct block_device *bdev)
> +{
> + u64 zone_size;
> +
> + if (btrfs_is_zoned(fs_info)) {
> + zone_size = (u64)bdev_zone_sectors(bdev) << SECTOR_SHIFT;
> + /* Do not allow non-zoned device */
This comment does not make sense. It should be:
/* Only allow zoned devices with the same zone size */
> + return bdev_is_zoned(bdev) && fs_info->zone_size == zone_size;
> + }
> +
> + /* Do not allow Host Manged zoned device */
> + return bdev_zoned_model(bdev) != BLK_ZONED_HM;
The comment is also wrong. It should read:
/* Allow only host managed zoned devices */
This is because we decided to treat host aware devices in the same way as
regular block devices, since HA drives are backward compatible with regular
block devices.
> +}
>
>
> Also, if there is a new type of zoned device in the future, the older
> kernel should be able to reject the newer zone device types.
>
> And, if possible could you rename above function to
> btrfs_zone_type_is_valid(). Or better.
>
>
>>> right? What if in a non-zoned FS, a zoned device is added through the
>>> replace. No?
>>
>> The types of devices cannot mix, yeah. So I'd like to know the answer as
>> well.
>
>
>>>> --- a/fs/btrfs/volumes.c
>>>> +++ b/fs/btrfs/volumes.c
>>>> @@ -2518,6 +2518,11 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path
>>>> if (IS_ERR(bdev))
>>>> return PTR_ERR(bdev);
>>>>
>>>> + if (!btrfs_check_device_zone_type(fs_info, bdev)) {
>>>> + ret = -EINVAL;
>>>> + goto error;
>>>> + }
>>>> +
>>>> if (fs_devices->seeding) {
>>>> seeding_dev = 1;
>>>> down_write(&sb->s_umount);
>>>
>>> Same here too. It can also happen that a zone device is added to a non
>>> zoned fs.
>
>
> Thanks.
>
--
Damien Le Moal
Western Digital Research
