From: David Sterba <dsterba@suse.cz>

Date: Wed, 23 Jul 2014 14:39:35 +0200

Subject: [PATCH] btrfs: wake up transaction thread from SYNC_FS ioctl

(cherry picked from commit 2fad4e83e12591eb3bd213875b9edc2d18e93383)

The transaction thread may want to do more work, namely it pokes the

cleaner ktread that will start processing uncleaned subvols.

This can be triggered by user via the 'btrfs fi sync' command, otherwise

there was a delay up to 30 seconds before the cleaner started to clean

old snapshots.

Signed-off-by: David Sterba <dsterba@suse.cz>

Signed-off-by: Chris Mason <clm@fb.com>

---

 fs/btrfs/ioctl.c | 6 ++++++

 1 file changed, 6 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c

index 8a8e29878c34..13d577b39bfa 100644

--- a/fs/btrfs/ioctl.c

+++ b/fs/btrfs/ioctl.c

@@ -5283,6 +5283,12 @@ long btrfs_ioctl(struct file *file, unsigned int

 		if (ret)

 			return ret;

 		ret = btrfs_sync_fs(file->f_dentry->d_sb, 1);

+		/*

+		 * The transaction thread may want to do more work,

+		 * namely it pokes the cleaner ktread that will start

+		 * processing uncleaned subvols.

+		 */

+		wake_up_process(root->fs_info->transaction_kthread);

 		return ret;

 	}

 	case BTRFS_IOC_START_SYNC:

-- 

1.9.3