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-rw-r--r--fs/dax.c63
1 files changed, 63 insertions, 0 deletions
diff --git a/fs/dax.c b/fs/dax.c
index b646a46e4d12..a77394fe586e 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -298,6 +298,63 @@ static void put_unlocked_mapping_entry(struct address_space *mapping,
dax_wake_mapping_entry_waiter(mapping, index, entry, false);
}
+static unsigned long dax_entry_size(void *entry)
+{
+ if (dax_is_zero_entry(entry))
+ return 0;
+ else if (dax_is_empty_entry(entry))
+ return 0;
+ else if (dax_is_pmd_entry(entry))
+ return PMD_SIZE;
+ else
+ return PAGE_SIZE;
+}
+
+static unsigned long dax_radix_end_pfn(void *entry)
+{
+ return dax_radix_pfn(entry) + dax_entry_size(entry) / PAGE_SIZE;
+}
+
+/*
+ * Iterate through all mapped pfns represented by an entry, i.e. skip
+ * 'empty' and 'zero' entries.
+ */
+#define for_each_mapped_pfn(entry, pfn) \
+ for (pfn = dax_radix_pfn(entry); \
+ pfn < dax_radix_end_pfn(entry); pfn++)
+
+static void dax_associate_entry(void *entry, struct address_space *mapping)
+{
+ unsigned long pfn;
+
+ if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
+ return;
+
+ for_each_mapped_pfn(entry, pfn) {
+ struct page *page = pfn_to_page(pfn);
+
+ WARN_ON_ONCE(page->mapping);
+ page->mapping = mapping;
+ }
+}
+
+static void dax_disassociate_entry(void *entry, struct address_space *mapping,
+ bool trunc)
+{
+ unsigned long pfn;
+
+ if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
+ return;
+
+ for_each_mapped_pfn(entry, pfn) {
+ struct page *page = pfn_to_page(pfn);
+
+ WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
+ WARN_ON_ONCE(page->mapping && page->mapping != mapping);
+ page->mapping = NULL;
+ }
+}
+
/*
* Find radix tree entry at given index. If it points to an exceptional entry,
* return it with the radix tree entry locked. If the radix tree doesn't
@@ -404,6 +461,7 @@ restart:
}
if (pmd_downgrade) {
+ dax_disassociate_entry(entry, mapping, false);
radix_tree_delete(&mapping->page_tree, index);
mapping->nrexceptional--;
dax_wake_mapping_entry_waiter(mapping, index, entry,
@@ -453,6 +511,7 @@ static int __dax_invalidate_mapping_entry(struct address_space *mapping,
(radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) ||
radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)))
goto out;
+ dax_disassociate_entry(entry, mapping, trunc);
radix_tree_delete(page_tree, index);
mapping->nrexceptional--;
ret = 1;
@@ -547,6 +606,10 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
spin_lock_irq(&mapping->tree_lock);
new_entry = dax_radix_locked_entry(pfn, flags);
+ if (dax_entry_size(entry) != dax_entry_size(new_entry)) {
+ dax_disassociate_entry(entry, mapping, false);
+ dax_associate_entry(new_entry, mapping);
+ }
if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
/*