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: c2a7d2a115525d3501d38e23d24875a79a07e15e
Reported-by: Barret Rhoden <brho@xxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/dax.c | 1 +
1 file changed, 1 insertion(+)
Dan, can you please get this merged? Otherwise dax_lock_mapping_entry()
deadlocks as soon as there's any contention.
diff --git a/fs/dax.c b/fs/dax.c
index b68ce484e1be..4becbf168b7f 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -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;
}
--
2.16.4
