Commit f52afc93 authored by Jan Kara's avatar Jan Kara Committed by Dan Williams

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: default avatarBarret Rhoden <brho@google.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 6bf4ca7f
...@@ -447,6 +447,7 @@ bool dax_lock_mapping_entry(struct page *page) ...@@ -447,6 +447,7 @@ bool dax_lock_mapping_entry(struct page *page)
xa_unlock_irq(&mapping->i_pages); xa_unlock_irq(&mapping->i_pages);
break; break;
} else if (IS_ERR(entry)) { } else if (IS_ERR(entry)) {
xa_unlock_irq(&mapping->i_pages);
WARN_ON_ONCE(PTR_ERR(entry) != -EAGAIN); WARN_ON_ONCE(PTR_ERR(entry) != -EAGAIN);
continue; continue;
} }
......
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