69 lines
2.5 KiB
Diff
69 lines
2.5 KiB
Diff
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From 81baeb2a67d8245ac5b61299e54dd65defd4ac72 Mon Sep 17 00:00:00 2001
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From: Qu Wenruo <wqu@suse.com>
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Date: Tue, 10 Sep 2024 15:21:04 +0930
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Subject: btrfs: qgroup: set a more sane default value for subtree drop
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threshold
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Since commit 011b46c30476 ("btrfs: skip subtree scan if it's too high to
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avoid low stall in btrfs_commit_transaction()"), btrfs qgroup can
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automatically skip large subtree scan at the cost of marking qgroup
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inconsistent.
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It's designed to address the final performance problem of snapshot drop
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with qgroup enabled, but to be safe the default value is
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BTRFS_MAX_LEVEL, requiring a user space daemon to set a different value
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to make it work.
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I'd say it's not a good idea to rely on user space tool to set this
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default value, especially when some operations (snapshot dropping) can
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be triggered immediately after mount, leaving a very small window to
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that that sysfs interface.
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So instead of disabling this new feature by default, enable it with a
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low threshold (3), so that large subvolume tree drop at mount time won't
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cause huge qgroup workload.
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CC: stable@vger.kernel.org # 6.1
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Signed-off-by: Qu Wenruo <wqu@suse.com>
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Reviewed-by: David Sterba <dsterba@suse.com>
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Signed-off-by: David Sterba <dsterba@suse.com>
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---
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fs/btrfs/disk-io.c | 2 +-
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fs/btrfs/qgroup.c | 2 +-
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fs/btrfs/qgroup.h | 2 ++
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3 files changed, 4 insertions(+), 2 deletions(-)
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--- a/fs/btrfs/disk-io.c
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+++ b/fs/btrfs/disk-io.c
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@@ -1960,7 +1960,7 @@ static void btrfs_init_qgroup(struct btr
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fs_info->qgroup_seq = 1;
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fs_info->qgroup_ulist = NULL;
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fs_info->qgroup_rescan_running = false;
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- fs_info->qgroup_drop_subtree_thres = BTRFS_MAX_LEVEL;
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+ fs_info->qgroup_drop_subtree_thres = BTRFS_QGROUP_DROP_SUBTREE_THRES_DEFAULT;
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mutex_init(&fs_info->qgroup_rescan_lock);
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}
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--- a/fs/btrfs/qgroup.c
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+++ b/fs/btrfs/qgroup.c
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@@ -1407,7 +1407,7 @@ int btrfs_quota_disable(struct btrfs_fs_
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fs_info->quota_root = NULL;
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fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
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fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE;
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- fs_info->qgroup_drop_subtree_thres = BTRFS_MAX_LEVEL;
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+ fs_info->qgroup_drop_subtree_thres = BTRFS_QGROUP_DROP_SUBTREE_THRES_DEFAULT;
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spin_unlock(&fs_info->qgroup_lock);
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btrfs_free_qgroup_config(fs_info);
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--- a/fs/btrfs/qgroup.h
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+++ b/fs/btrfs/qgroup.h
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@@ -121,6 +121,8 @@ struct btrfs_inode;
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#define BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN (1ULL << 63)
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#define BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING (1ULL << 62)
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+#define BTRFS_QGROUP_DROP_SUBTREE_THRES_DEFAULT (3)
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+
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/*
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* Record a dirty extent, and info qgroup to update quota on it
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*/
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