At 05/23/2017 01:31 AM, Sargun Dhillon wrote:
On Sun, May 21, 2017 at 7:03 PM, Qu Wenruo <[email protected]> wrote:
At 05/22/2017 09:58 AM, Sargun Dhillon wrote:
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.
So, just to bring this full circle before I do a v2, we want to make
it so on creation time, or after creation time you can make a qgroup
autoremove. And we want this to be a flag that gets inherited if
SUBVOL_QGROUP_INHERIT is set?
Errr, another line I forgot to remove.
As long as you're going to introduce new API, there is no need to modify
old structure.
So my idea is:
1) Introduce new API
2) Add btrfs_info/btrfs_debug for old API
And make it default to disallow creating level 0 qgroups, and auto
remove level 0 qgroups when creating new subvolume.
3) That's all
Thanks,
Qu
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?
Sorry, I didn't see later patches.
Yes, new API is a better method to solve this problem.
But with new APIs, the need of new mount option is even less.
Outputting a warning message in dmesg is good enough to info user to use new
API.
Thanks,
Qu
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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