splice: handle try_to_release_page() failure

splice currently assumes that try_to_release_page() always suceeds,
but it can return failure. If it does, we cannot steal the page.

Acked-by: Mingming Cao <cmm@us.ibm.com
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/splice.c b/fs/splice.c
index a048ad2130c3..aa5f6f60b305 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -58,8 +58,8 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
                  */
                 wait_on_page_writeback(page);
 
-                if (PagePrivate(page))
-                        try_to_release_page(page, GFP_KERNEL);
+                if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL))
+                        goto out_unlock;
 
                 /*
                  * If we succeeded in removing the mapping, set LRU flag
@@ -75,6 +75,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
          * Raced with truncate or failed to remove page from current
          * address space, unlock and return failure.
          */
+out_unlock:
         unlock_page(page);
         return 1;
 }