fs/mpage.c: factor page_endio() out of mpage_end_io()

page_endio() takes care of updating all the appropriate page flags once
I/O has finished to a page.  Switch to using mapping_set_error() instead
of setting AS_EIO directly; this will handle thin-provisioned devices
correctly.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dheeraj Reddy <dheeraj.reddy@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 28 insertions, 17 deletions

diff --git a/fs/mpage.c b/fs/mpage.c
index 4cc9c5d079f7..10da0da73017 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -48,23 +48,7 @@ static void mpage_end_io(struct bio *bio, int err)
 
         bio_for_each_segment_all(bv, bio, i) {
                 struct page *page = bv->bv_page;
-
-                if (bio_data_dir(bio) == READ) {
-                        if (!err) {
-                                SetPageUptodate(page);
-                        } else {
-                                ClearPageUptodate(page);
-                                SetPageError(page);
-                        }
-                        unlock_page(page);
-                } else { /* bio_data_dir(bio) == WRITE */
-                        if (err) {
-                                SetPageError(page);
-                                if (page->mapping)
-                                        set_bit(AS_EIO, &page->mapping->flags);
-                        }
-                        end_page_writeback(page);
-                }
+                page_endio(page, bio_data_dir(bio), err);
         }
 
         bio_put(bio);
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 45598f1e9aa3..718214c5584e 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -425,6 +425,8 @@ static inline void wait_on_page_writeback(struct page *page)
 extern void end_page_writeback(struct page *page);
 void wait_for_stable_page(struct page *page);
 
+void page_endio(struct page *page, int rw, int err);
+
 /*
  * Add an arbitrary waiter to a page's wait queue
  */
diff --git a/mm/filemap.c b/mm/filemap.c
index 021056c324e6..47d235b357a7 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -764,6 +764,31 @@ void end_page_writeback(struct page *page)
 }
 EXPORT_SYMBOL(end_page_writeback);
 
+/*
+ * After completing I/O on a page, call this routine to update the page
+ * flags appropriately
+ */
+void page_endio(struct page *page, int rw, int err)
+{
+        if (rw == READ) {
+                if (!err) {
+                        SetPageUptodate(page);
+                } else {
+                        ClearPageUptodate(page);
+                        SetPageError(page);
+                }
+                unlock_page(page);
+        } else { /* rw == WRITE */
+                if (err) {
+                        SetPageError(page);
+                        if (page->mapping)
+                                mapping_set_error(page->mapping, err);
+                }
+                end_page_writeback(page);
+        }
+}
+EXPORT_SYMBOL_GPL(page_endio);
+
 /**
  * __lock_page - get a lock on the page, assuming we need to sleep to get it
  * @page: the page to lock