Rob Norris 670147be53 zvol: ensure device minors are properly cleaned up ... Currently, if a minor is in use when we try to remove it, we'll skip it and never come back to it again. Since the zvol state is hung off the minor in the kernel, this can get us into weird situations if something tries to use it after the removal fails. It's even worse at pool export, as there's now a vestigial zvol state with no pool under it. It's weirder again if the pool is subsequently reimported, as the zvol code (reasonably) assumes the zvol state has been properly setup, when it's actually left over from the previous import of the pool. This commit attempts to tackle that by setting a flag on the zvol if its minor can't be removed, and then checking that flag when a request is made and rejecting it, thus stopping new work coming in. The flag also causes a condvar to be signaled when the last client finishes. For the case where a single minor is being removed (eg changing volmode), it will wait for this signal before proceeding. Meanwhile, when removing all minors, a background task is created for each minor that couldn't be removed on the spot, and those tasks then wake and clean up. Since any new tasks are queued on to the pool's spa_zvol_taskq, spa_export_common() will continue to wait at export until all minors are removed. Reviewed-by: Tony Hutter <hutter2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Sponsored-by: Klara, Inc. Sponsored-by: Wasabi Technology, Inc. Signed-off-by: Rob Norris <rob.norris@klarasystems.com> Closes #14872 Closes #16364		2024-08-06 12:08:14 -07:00
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freebsd	zvol: ensure device minors are properly cleaned up	2024-08-06 12:08:14 -07:00
linux	zvol: ensure device minors are properly cleaned up	2024-08-06 12:08:14 -07:00