Commit f52afc93 authored Sep 27, 2018 by Jan Kara Committed by Dan Williams Sep 27, 2018

dax: Fix deadlock in dax_lock_mapping_entry()



When dax_lock_mapping_entry() has to sleep to obtain entry lock, it will
fail to unlock mapping->i_pages spinlock and thus immediately deadlock
against itself when retrying to grab the entry lock again. Fix the
problem by unlocking mapping->i_pages before retrying.

Fixes: c2a7d2a1 ("filesystem-dax: Introduce dax_lock_mapping_entry()")
Reported-by: Barret Rhoden <brho@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

parent 6bf4ca7f

fs/dax.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -447,6 +447,7 @@ bool dax_lock_mapping_entry(struct page *page)
		xa_unlock_irq(&mapping->i_pages);
		break;
		} else if (IS_ERR(entry)) {
		xa_unlock_irq(&mapping->i_pages);
		WARN_ON_ONCE(PTR_ERR(entry) != -EAGAIN);
		continue;
		}