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authorBoris Burkov <boris@bur.io>2023-03-28 13:55:25 -0700
committerDavid Sterba <dsterba@suse.com>2023-10-12 16:44:11 +0200
commit5343cd9364ea26c9f4f78896a87ed1b5b5e652d9 (patch)
tree9a4f7d24df5ca55a292be21e234a1da22d0af2ec /fs/btrfs/ioctl.c
parentcecbb533b5fcec4ff77e786b7f94457f6cacd9e7 (diff)
btrfs: qgroup: simple quota auto hierarchy for nested subvolumes
Consider the following sequence: - enable quotas - create subvol S id 256 at dir outer/ - create a qgroup 1/100 - add 0/256 (S's auto qgroup) to 1/100 - create subvol T id 257 at dir outer/inner/ With full qgroups, there is no relationship between 0/257 and either of 0/256 or 1/100. There is an inherit feature that the creator of inner/ can use to specify it ought to be in 1/100. Simple quotas are targeted at container isolation, where such automatic inheritance for not necessarily trusted/controlled nested subvol creation would be quite helpful. Therefore, add a new default behavior for simple quotas: when you create a nested subvol, automatically inherit as parents any parents of the qgroup of the subvol the new inode is going in. In our example, 257/0 would also be under 1/100, allowing easy control of a total quota over an arbitrary hierarchy of subvolumes. I think this _might_ be a generally useful behavior, so it could be interesting to put it behind a new inheritance flag that simple quotas always use while traditional quotas let the user specify, but this is a minimally intrusive change to start. Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/ioctl.c')
-rw-r--r--fs/btrfs/ioctl.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 58189d99a22c..6603b6fff93f 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -652,7 +652,7 @@ static noinline int create_subvol(struct mnt_idmap *idmap,
/* Tree log can't currently deal with an inode which is a new root. */
btrfs_set_log_full_commit(trans);
- ret = btrfs_qgroup_inherit(trans, 0, objectid, inherit);
+ ret = btrfs_qgroup_inherit(trans, 0, objectid, root->root_key.objectid, inherit);
if (ret)
goto out;