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-rw-r--r--fs/dax.c71
-rw-r--r--include/linux/dax.h3
-rw-r--r--mm/truncate.c75
3 files changed, 125 insertions, 24 deletions
diff --git a/fs/dax.c b/fs/dax.c
index a8732fb..bcfedd1 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -451,16 +451,37 @@ void dax_wake_mapping_entry_waiter(struct address_space *mapping,
__wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key);
}
+static int __dax_invalidate_mapping_entry(struct address_space *mapping,
+ pgoff_t index, bool trunc)
+{
+ int ret = 0;
+ void *entry;
+ struct radix_tree_root *page_tree = &mapping->page_tree;
+
+ spin_lock_irq(&mapping->tree_lock);
+ entry = get_unlocked_mapping_entry(mapping, index, NULL);
+ if (!entry || !radix_tree_exceptional_entry(entry))
+ goto out;
+ if (!trunc &&
+ (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) ||
+ radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)))
+ goto out;
+ radix_tree_delete(page_tree, index);
+ mapping->nrexceptional--;
+ ret = 1;
+out:
+ put_unlocked_mapping_entry(mapping, index, entry);
+ spin_unlock_irq(&mapping->tree_lock);
+ return ret;
+}
/*
* Delete exceptional DAX entry at @index from @mapping. Wait for radix tree
* entry to get unlocked before deleting it.
*/
int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
{
- void *entry;
+ int ret = __dax_invalidate_mapping_entry(mapping, index, true);
- spin_lock_irq(&mapping->tree_lock);
- entry = get_unlocked_mapping_entry(mapping, index, NULL);
/*
* This gets called from truncate / punch_hole path. As such, the caller
* must hold locks protecting against concurrent modifications of the
@@ -468,16 +489,46 @@ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
* caller has seen exceptional entry for this index, we better find it
* at that index as well...
*/
- if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry))) {
- spin_unlock_irq(&mapping->tree_lock);
- return 0;
- }
- radix_tree_delete(&mapping->page_tree, index);
+ WARN_ON_ONCE(!ret);
+ return ret;
+}
+
+/*
+ * Invalidate exceptional DAX entry if easily possible. This handles DAX
+ * entries for invalidate_inode_pages() so we evict the entry only if we can
+ * do so without blocking.
+ */
+int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index)
+{
+ int ret = 0;
+ void *entry, **slot;
+ struct radix_tree_root *page_tree = &mapping->page_tree;
+
+ spin_lock_irq(&mapping->tree_lock);
+ entry = __radix_tree_lookup(page_tree, index, NULL, &slot);
+ if (!entry || !radix_tree_exceptional_entry(entry) ||
+ slot_locked(mapping, slot))
+ goto out;
+ if (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) ||
+ radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))
+ goto out;
+ radix_tree_delete(page_tree, index);
mapping->nrexceptional--;
+ ret = 1;
+out:
spin_unlock_irq(&mapping->tree_lock);
- dax_wake_mapping_entry_waiter(mapping, index, entry, true);
+ if (ret)
+ dax_wake_mapping_entry_waiter(mapping, index, entry, true);
+ return ret;
+}
- return 1;
+/*
+ * Invalidate exceptional DAX entry if it is clean.
+ */
+int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
+ pgoff_t index)
+{
+ return __dax_invalidate_mapping_entry(mapping, index, false);
}
/*
diff --git a/include/linux/dax.h b/include/linux/dax.h
index f97bcfe..24ad711 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -41,6 +41,9 @@ ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
struct iomap_ops *ops);
int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
+int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index);
+int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
+ pgoff_t index);
void dax_wake_mapping_entry_waiter(struct address_space *mapping,
pgoff_t index, void *entry, bool wake_all);
diff --git a/mm/truncate.c b/mm/truncate.c
index fd97f1d..dd7b24e 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -24,20 +24,12 @@
#include <linux/rmap.h>
#include "internal.h"
-static void clear_exceptional_entry(struct address_space *mapping,
- pgoff_t index, void *entry)
+static void clear_shadow_entry(struct address_space *mapping, pgoff_t index,
+ void *entry)
{
struct radix_tree_node *node;
void **slot;
- /* Handled by shmem itself */
- if (shmem_mapping(mapping))
- return;
-
- if (dax_mapping(mapping)) {
- dax_delete_mapping_entry(mapping, index);
- return;
- }
spin_lock_irq(&mapping->tree_lock);
/*
* Regular page slots are stabilized by the page lock even
@@ -55,6 +47,56 @@ unlock:
spin_unlock_irq(&mapping->tree_lock);
}
+/*
+ * Unconditionally remove exceptional entry. Usually called from truncate path.
+ */
+static void truncate_exceptional_entry(struct address_space *mapping,
+ pgoff_t index, void *entry)
+{
+ /* Handled by shmem itself */
+ if (shmem_mapping(mapping))
+ return;
+
+ if (dax_mapping(mapping)) {
+ dax_delete_mapping_entry(mapping, index);
+ return;
+ }
+ clear_shadow_entry(mapping, index, entry);
+}
+
+/*
+ * Invalidate exceptional entry if easily possible. This handles exceptional
+ * entries for invalidate_inode_pages() so for DAX it evicts only unlocked and
+ * clean entries.
+ */
+static int invalidate_exceptional_entry(struct address_space *mapping,
+ pgoff_t index, void *entry)
+{
+ /* Handled by shmem itself */
+ if (shmem_mapping(mapping))
+ return 1;
+ if (dax_mapping(mapping))
+ return dax_invalidate_mapping_entry(mapping, index);
+ clear_shadow_entry(mapping, index, entry);
+ return 1;
+}
+
+/*
+ * Invalidate exceptional entry if clean. This handles exceptional entries for
+ * invalidate_inode_pages2() so for DAX it evicts only clean entries.
+ */
+static int invalidate_exceptional_entry2(struct address_space *mapping,
+ pgoff_t index, void *entry)
+{
+ /* Handled by shmem itself */
+ if (shmem_mapping(mapping))
+ return 1;
+ if (dax_mapping(mapping))
+ return dax_invalidate_mapping_entry_sync(mapping, index);
+ clear_shadow_entry(mapping, index, entry);
+ return 1;
+}
+
/**
* do_invalidatepage - invalidate part or all of a page
* @page: the page which is affected
@@ -262,7 +304,8 @@ void truncate_inode_pages_range(struct address_space *mapping,
break;
if (radix_tree_exceptional_entry(page)) {
- clear_exceptional_entry(mapping, index, page);
+ truncate_exceptional_entry(mapping, index,
+ page);
continue;
}
@@ -351,7 +394,8 @@ void truncate_inode_pages_range(struct address_space *mapping,
}
if (radix_tree_exceptional_entry(page)) {
- clear_exceptional_entry(mapping, index, page);
+ truncate_exceptional_entry(mapping, index,
+ page);
continue;
}
@@ -470,7 +514,8 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
break;
if (radix_tree_exceptional_entry(page)) {
- clear_exceptional_entry(mapping, index, page);
+ invalidate_exceptional_entry(mapping, index,
+ page);
continue;
}
@@ -592,7 +637,9 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
break;
if (radix_tree_exceptional_entry(page)) {
- clear_exceptional_entry(mapping, index, page);
+ if (!invalidate_exceptional_entry2(mapping,
+ index, page))
+ ret = -EBUSY;
continue;
}
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