ceph: fix error handling of start_read()

If start_page() fails to add a page to page cache or fails to send
OSD request. It should cal put_page() (instead of free_page()) for
relevant pages.

Besides, start_page() need to cancel fscache readpage if it fails
to send OSD request.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reported-by: Zhi Zhang <zhang.david2011@gmail.com>

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index d5b6f959a3c3a418aa2bbcbf67a9823b17bee73d..f410a0cb57e30d9ede1988aaedab87aa482d74db 100644 (file)
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -298,14 +298,6 @@ unlock:
        kfree(osd_data->pages);
 }
 
-static void ceph_unlock_page_vector(struct page **pages, int num_pages)
-{
-       int i;
-
-       for (i = 0; i < num_pages; i++)
-               unlock_page(pages[i]);
-}
-
 /*
  * start an async read(ahead) operation.  return nr_pages we submitted
  * a read for on success, or negative error code.
@@ -370,6 +362,10 @@ static int start_read(struct inode *inode, struct list_head *page_list, int max)
                        dout("start_read %p add_to_page_cache failed %p\n",
                             inode, page);
                        nr_pages = i;
+                       if (nr_pages > 0) {
+                               len = nr_pages << PAGE_SHIFT;
+                               break;
+                       }
                        goto out_pages;
                }
                pages[i] = page;
@@ -386,8 +382,11 @@ static int start_read(struct inode *inode, struct list_head *page_list, int max)
        return nr_pages;
 
 out_pages:
-       ceph_unlock_page_vector(pages, nr_pages);
-       ceph_release_page_vector(pages, nr_pages);
+       for (i = 0; i < nr_pages; ++i) {
+               ceph_fscache_readpage_cancel(inode, pages[i]);
+               unlock_page(pages[i]);
+       }
+       ceph_put_page_vector(pages, nr_pages, false);
 out:
        ceph_osdc_put_request(req);
        return ret;