24.03.2020 20:59, Goffredo Baroncelli пишет: > On 3/24/20 5:55 AM, Anand Jain wrote: >> On 3/21/20 1:56 AM, Goffredo Baroncelli wrote: >>> Hi all, > [..] >>> Looking at the code it seems to me that the logic is the following >>> (from btrfs_reduce_alloc_profile()) >>> >>> if (allowed & BTRFS_BLOCK_GROUP_RAID6) >>> allowed = BTRFS_BLOCK_GROUP_RAID6; >>> else if (allowed & BTRFS_BLOCK_GROUP_RAID5) >>> allowed = BTRFS_BLOCK_GROUP_RAID5; >>> else if (allowed & BTRFS_BLOCK_GROUP_RAID10) >>> allowed = BTRFS_BLOCK_GROUP_RAID10; >>> else if (allowed & BTRFS_BLOCK_GROUP_RAID1) >>> allowed = BTRFS_BLOCK_GROUP_RAID1; >>> else if (allowed & BTRFS_BLOCK_GROUP_RAID0) >>> allowed = BTRFS_BLOCK_GROUP_RAID0; >>> >>> flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK; >>> >>> So in the case above the profile will be RAID6. And in the general if >>> a RAID6 chunk is a filesystem, it wins ! >> >> That's arbitrary and doesn't make sense to me, IMO mkfs should save >> default profile in the super-block (which can be changed using ioctl) >> and kernel can create chunks based on the default profile. > > I'm working on this idea (storing the target profile in super-block). What about per-subvolume profile? This comes up every now and then, like https://lore.kernel.org/linux-btrfs/cd82d247-5c95-18cd-a290-a911ff69613c@xxxxxxxxxxxxxx/ May be it could be subvolume property? > Of > course this increase the consistency, but > doesn't prevent the possibility that a mixed profiles filesystem could > happen. And in this case is the user that > has to solve the issue. > > Zygo, suggested also to add a mixed profile warning to btrfs (prog). And > I agree with him. I think that we can use > the space info ioctl (which doesn't require root privileges). > > BR > G.Baroncelli > >> This >> approach also fixes chunk size inconsistency between progs and kernel >> as reported/fixed here >> https://patchwork.kernel.org/patch/11431405/ >> >> Thanks, Anand >> >>> But I am not sure.. Moreover I expected to see also reference to DUP >>> and/or RAID1C[34] ... >>> >>> Does someone have any suggestion ? >>> >>> BR >>> G.Baroncelli >>> >> > >
