| Message ID | 1425025468-29749-3-git-send-email-quwenruo@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On 02/27/2015 03:24 AM, Qu Wenruo wrote: > Btrfs will create qgroup on subvolume creation if quota is enabled, but > qgroup uses the high bits(currently 16 bits) as level, to build the > inheritance. > > However it is fully possible a subvolume can be created with a > subvolumeid larger than 1 << BTRFS_QGROUP_LEVEL_SHIFT, so it will be > considered as level 1 and can't be assigned to other qgroup in level 1. > > This patch will prevent such things so qgroup inheritance will not be > screwed up. > The downside is very clear, btrfs subvolume number limit will decrease > from (u64 max - 256(fisrt free objectid) - 256(last free objectid)) to > (u48 max -256(first free objectid)). > But we still have near u48(that's 15 digits in dec), so that should not > be a huge problem. > > Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index cbaf1a4..fb4b52b 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -4200,7 +4200,8 @@ int btree_readahead_hook(struct btrfs_root *root, struct extent_buffer *eb, static inline int is_fstree(u64 rootid) { if (rootid == BTRFS_FS_TREE_OBJECTID || - (s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID) + ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID && + !btrfs_qgroup_level(rootid))) return 1; return 0; } diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index d49fe8a..f93ca4b 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -456,6 +456,13 @@ static noinline int create_subvol(struct inode *dir, if (ret) return ret; + /* + * Don't create subvolume whose level is not zero. Or qgroup will be + * screwed up since it assume subvolme qgroup's level to be 0. + */ + if (btrfs_qgroup_level(objectid)) + return -ENOSPC; + btrfs_init_block_rsv(&block_rsv, BTRFS_BLOCK_RSV_TEMP); /* * The same as the snapshot creation, please see the comment
Btrfs will create qgroup on subvolume creation if quota is enabled, but qgroup uses the high bits(currently 16 bits) as level, to build the inheritance. However it is fully possible a subvolume can be created with a subvolumeid larger than 1 << BTRFS_QGROUP_LEVEL_SHIFT, so it will be considered as level 1 and can't be assigned to other qgroup in level 1. This patch will prevent such things so qgroup inheritance will not be screwed up. The downside is very clear, btrfs subvolume number limit will decrease from (u64 max - 256(fisrt free objectid) - 256(last free objectid)) to (u48 max -256(first free objectid)). But we still have near u48(that's 15 digits in dec), so that should not be a huge problem. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> --- fs/btrfs/ctree.h | 3 ++- fs/btrfs/ioctl.c | 7 +++++++ 2 files changed, 9 insertions(+), 1 deletion(-)