Hi! Is it technically possible to wait for a snapshot completely purged from disk? I imagine an option like "--wait" for btrfs delete subvolume.
This would fit some purposes I'm planning to implement: * In a backup scenario have a subprocess which deletes snapshots one by one, starting with the oldest. If free space raises above a certain threshold, pause the subprocess. If number of kept snapshots falls below a certain threshold, exit the subprocess. When the backup job finished, it joins the subprocess to wait for a pending subvolume deletion if any, then syncs the filesystem and waits some grace time for uncommitted writes, then shuts the system down or hibernates it. * Wait for pending background subvolume deletion before putting the system to sleep. * Get better control of cron jobs working with subvolumes so jobs either do not overlap or do not put too much parallel work on the file system. Scrubbing does allow that. Why don't snapshots do? At least I found no options for it. Background information: If btrfs is shut down improperly, already deleted subvolume entries may reappear in their directories. The deletion is not gracefully resumed. Since deletion of subvolumes/snapshots can take hours, this is a problem for systems that are not guaranteed to be up all the time or suffer from disconnected power, especially if multiple snapshots are being deleted at once. With an option to wait, a script managing snapshot deletion could more gracefully resume its job. -- Replies to list only preferred. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
