Merge tag 'upstream-4.7-rc5' of git://git.infradead.org/linux-ubifs

Pull UBI/UBIFS fixes from Richard Weinberger:
 "This contains fixes for two critical bugs in UBI and UBIFS:

   - fix the possibility of losing data upon a power cut when UBI tries
     to recover from a write error

   - fix page migration on UBIFS.  It turned out that the default page
     migration function is not suitable for UBIFS"

* tag 'upstream-4.7-rc5' of git://git.infradead.org/linux-ubifs:
  UBIFS: Implement ->migratepage()
  mm: Export migrate_page_move_mapping and migrate_page_copy
  ubi: Make recover_peb power cut aware
  gpio: make library immune to error pointers
  gpio: make sure gpiod_to_irq() returns negative on NULL desc
  gpio: 104-idi-48: Fix missing spin_lock_init for ack_lock

1 files changed, 24 insertions, 0 deletions

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 0831697..7bbf420 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -52,6 +52,7 @@
 #include "ubifs.h"
 #include <linux/mount.h>
 #include <linux/slab.h>
+#include <linux/migrate.h>
 
 static int read_block(struct inode *inode, void *addr, unsigned int block,
 		      struct ubifs_data_node *dn)
@@ -1452,6 +1453,26 @@ static int ubifs_set_page_dirty(struct page *page)
 	return ret;
 }
 
+#ifdef CONFIG_MIGRATION
+static int ubifs_migrate_page(struct address_space *mapping,
+		struct page *newpage, struct page *page, enum migrate_mode mode)
+{
+	int rc;
+
+	rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0);
+	if (rc != MIGRATEPAGE_SUCCESS)
+		return rc;
+
+	if (PagePrivate(page)) {
+		ClearPagePrivate(page);
+		SetPagePrivate(newpage);
+	}
+
+	migrate_page_copy(newpage, page);
+	return MIGRATEPAGE_SUCCESS;
+}
+#endif
+
 static int ubifs_releasepage(struct page *page, gfp_t unused_gfp_flags)
 {
 	/*
@@ -1591,6 +1612,9 @@ const struct address_space_operations ubifs_file_address_operations = {
 	.write_end      = ubifs_write_end,
 	.invalidatepage = ubifs_invalidatepage,
 	.set_page_dirty = ubifs_set_page_dirty,
+#ifdef CONFIG_MIGRATION
+	.migratepage	= ubifs_migrate_page,
+#endif
 	.releasepage    = ubifs_releasepage,
 };