[LU-10769] osd-zfs deadlock on osd_object::oo_guard

Duplicate — Mon, 9 Apr 2018 23:36:44 +0000

Consider the following scenarios:

1) The Thread1 calls osd_attr_set() to set flags on the object. The osd_attr_set() will call the osd_xattr_get() with holding the read mode semaphore on the object::oo_guard.

2) The Thread2 calls osd_declare_destroy() to destroy the object, it will down_write() on the object::oo_gurad, but be blocked by the Thread1's granted read mode semaphore.

3) The osd_xattr_get() triggered by the osd_xattr_set() will also down_read() on the object::oo_guard. But it will be blocked by the Thread2's pending down_write() request.

Then the Thread1 and the Thread2 deadlock.

Whamcloud Community JIRA

[LU-10769] osd-zfs deadlock on osd_object::oo_guard