btrfs: explictly delete unused block groups in close_ctree and ro-remount (e44163e1) · Commits · 戴 / test

The cleaner thread may already be sleeping by the time we enter close_ctree. If that's the case, we'll skip removing any unused block groups queued for removal, even during a normal umount. They'll be cleaned up automatically at next mount, but users expect a umount to be a clean synchronization point, especially when used on thin-provisioned storage with -odiscard. We also explicitly remove unused block groups in the ro-remount path for the same reason. Signed-off-by:

Jeff Mahoney <jeffm@suse.com> Reviewed-by:

Filipe Manana <fdmanana@suse.com> Tested-by:

Filipe Manana <fdmanana@suse.com> Signed-off-by:

Chris Mason <clm@fb.com>

fs/btrfs/disk-io.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -3767,6 +3767,15 @@ void close_ctree(struct btrfs_root *root)
		cancel_work_sync(&fs_info->async_reclaim_work);

		if (!(fs_info->sb->s_flags & MS_RDONLY)) {
		/*
		* If the cleaner thread is stopped and there are
		* block groups queued for removal, the deletion will be
		* skipped when we quit the cleaner thread.
		*/
		mutex_lock(&root->fs_info->cleaner_mutex);
		btrfs_delete_unused_bgs(root->fs_info);
		mutex_unlock(&root->fs_info->cleaner_mutex);

		ret = btrfs_commit_super(root);
		if (ret)
		btrfs_err(fs_info, "commit super ret %d", ret);

fs/btrfs/super.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -1650,6 +1650,17 @@ static int btrfs_remount(struct super_block sb, int flags, char *data)

		sb->s_flags \|= MS_RDONLY;

		/*
		* Setting MS_RDONLY will put the cleaner thread to
		* sleep at the next loop if it's already active.
		* If it's already asleep, we'll leave unused block
		* groups on disk until we're mounted read-write again
		* unless we clean them up here.
		*/
		mutex_lock(&root->fs_info->cleaner_mutex);
		btrfs_delete_unused_bgs(fs_info);
		mutex_unlock(&root->fs_info->cleaner_mutex);

		btrfs_dev_replace_suspend_for_unmount(fs_info);
		btrfs_scrub_cancel(fs_info);
		btrfs_pause_balance(fs_info);

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