On Sun, May 21, 2017 at 6:20 PM, Qu Wenruo <[email protected]> wrote:
>
>
> At 05/20/2017 04:39 PM, Sargun Dhillon wrote:
>>
>> This change follows the change to automatically remove qgroups
>> if the associated subvolume has also been removed. It changes
>> the default behaviour to automatically remove qgroups when
>> a subvolume is deleted, but this can be override with the
>> qgroup_keep mount flag.
>>
>> Signed-off-by: Sargun Dhillon <[email protected]>
>> ---
>> fs/btrfs/ctree.h | 1 +
>> fs/btrfs/ioctl.c | 14 ++++++++++++++
>> fs/btrfs/super.c | 16 +++++++++++++++-
>> 3 files changed, 30 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
>> index 643c70d..4d57eb6 100644
>> --- a/fs/btrfs/ctree.h
>> +++ b/fs/btrfs/ctree.h
>> @@ -1348,6 +1348,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct
>> btrfs_fs_info *info)
>> #define BTRFS_MOUNT_FRAGMENT_METADATA (1 << 25)
>> #define BTRFS_MOUNT_FREE_SPACE_TREE (1 << 26)
>> #define BTRFS_MOUNT_NOLOGREPLAY (1 << 27)
>> +#define BTRFS_MOUNT_QGROUP_KEEP (1 << 28)
>> #define BTRFS_DEFAULT_COMMIT_INTERVAL (30)
>> #define BTRFS_DEFAULT_MAX_INLINE (2048)
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index e176375..b10d7bb 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -2544,6 +2544,20 @@ static noinline int btrfs_ioctl_snap_destroy(struct
>> file *file,
>> }
>> }
>> + /*
>> + * Attempt to automatically remove the automatically attached
>> qgroup
>> + * setup in btrfs_qgroup_inherit. As a matter of convention, the
>> id
>> + * is the same as the subvolume id.
>> + *
>> + * This can fail non-fatally for level 0 qgroups, and potentially
>> + * leave the filesystem in an awkward, (but working) state.
>> + */
>> + if (!btrfs_test_opt(fs_info, QGROUP_KEEP)) {
>> + ret = btrfs_remove_qgroup(trans, fs_info,
>> + dest->root_key.objectid);
>> + if (ret && ret != -ENOENT)
>> + pr_info("Could not automatically delete qgroup:
>> %d\n", ret);
>> + }
>> out_end_trans:
>> trans->block_rsv = NULL;
>> trans->bytes_reserved = 0;
>> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
>> index 4f1cdd5..232e1b8 100644
>> --- a/fs/btrfs/super.c
>> +++ b/fs/btrfs/super.c
>> @@ -321,7 +321,7 @@ enum {
>> Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
>> Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
>> Opt_datasum, Opt_treelog, Opt_noinode_cache, Opt_usebackuproot,
>> - Opt_nologreplay, Opt_norecovery,
>> + Opt_nologreplay, Opt_norecovery, Opt_qgroup_keep,
>> Opt_qgroup_nokeep,
>
>
> I prefer to add new meanings for btrfs_ioctl_qgroup_create_args->create.
I have two issues with this:
1) Existing software, like Docker Daemon. There's no way I can tell
Docker daemon to use this new flag to create qgroups. Although, I
could modify it, it doesn't fit into the API very well.
2) How do I do this with qgroups that already exist, or qgroups that
are created on-demand by qgroup_inherit?
I think both of these would be fixed if we copied (a subset) of the
qgroup flags. If you look at my other patches, I think we want to
remove the ability to remove level-0 qgroups (which are inherited), so
we'd also want to add an ioctl to be able to modify (some of those)
flags. Do you think that adding inheritance, and a new ioctl is a
reasonable approach?
>
> It's a u64 value while we only checks if it's zero or not, to determine if
> it's creation or deletion.
>
> We could reuse it to extent the create/delete behavior, other than a new
> mount option, which is a global flag, just to alter qgroup behavior.
>
> Thanks,
> Qu
>
>
>> #ifdef CONFIG_BTRFS_DEBUG
>> Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,
>> #endif
>> @@ -381,6 +381,8 @@ static const match_table_t tokens = {
>> {Opt_rescan_uuid_tree, "rescan_uuid_tree"},
>> {Opt_fatal_errors, "fatal_errors=%s"},
>> {Opt_commit_interval, "commit=%d"},
>> + {Opt_qgroup_keep, "qgroup_keep"},
>> + {Opt_qgroup_nokeep, "qgroup_nokeep"},
>> #ifdef CONFIG_BTRFS_DEBUG
>> {Opt_fragment_data, "fragment=data"},
>> {Opt_fragment_metadata, "fragment=metadata"},
>> @@ -808,6 +810,14 @@ int btrfs_parse_options(struct btrfs_fs_info *info,
>> char *options,
>> info->commit_interval =
>> BTRFS_DEFAULT_COMMIT_INTERVAL;
>> }
>> break;
>> + case Opt_qgroup_keep:
>> + btrfs_set_and_info(info, QGROUP_KEEP,
>> + "do not automatically delete
>> qgroups");
>> + break;
>> + case Opt_qgroup_nokeep:
>> + btrfs_clear_and_info(info, QGROUP_KEEP,
>> + "automatically delete
>> qgroups");
>> + break;
>> #ifdef CONFIG_BTRFS_DEBUG
>> case Opt_fragment_all:
>> btrfs_info(info, "fragmenting all space");
>> @@ -1299,6 +1309,10 @@ static int btrfs_show_options(struct seq_file *seq,
>> struct dentry *dentry)
>> seq_puts(seq, ",fatal_errors=panic");
>> if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
>> seq_printf(seq, ",commit=%d", info->commit_interval);
>> + if (btrfs_test_opt(info, QGROUP_KEEP))
>> + seq_puts(seq, ",qgroup_keep");
>> + else
>> + seq_puts(seq, ",qgroup_nokeep");
>> #ifdef CONFIG_BTRFS_DEBUG
>> if (btrfs_test_opt(info, FRAGMENT_DATA))
>> seq_puts(seq, ",fragment=data");
>>
>
>
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