Commit 6d7cd8c1 authored Nov 06, 2018 by Matthew Wilcox

dax: Remove optimisation from dax_lock_mapping_entry

Skipping some of the revalidation after we sleep can lead to returning
a mapping which has already been freed. Just drop this optimisation.

Reported-by: Dan Williams <dan.j.williams@intel.com>
Fixes: 9f32d221 ("dax: Convert dax_lock_mapping_entry to XArray")
Signed-off-by: Matthew Wilcox <willy@infradead.org>

parent 5404a7f1

fs/dax.c

+2 −5

Original line number	Diff line number	Diff line
		@@ -383,12 +383,9 @@ bool dax_lock_mapping_entry(struct page *page)
		entry = xas_load(&xas);
		if (dax_is_locked(entry)) {
		entry = get_unlocked_entry(&xas);
		/* Did the page move while we slept? */
		if (dax_to_pfn(entry) != page_to_pfn(page)) {
		xas_unlock_irq(&xas);
		continue;
		}
		}
		dax_lock_entry(&xas, entry);
		xas_unlock_irq(&xas);
		return true;

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