[PATCH] splice: fix unlocking of page on error ->prepare_write()

Looking at generic_file_buffered_write(), we need to unlock_page() if
prepare write fails and it isn't due to racing with truncate().

Also trim the size if ->prepare_write() fails, if we have to.

Signed-off-by: Jens Axboe <axboe@suse.de>

1 files changed, 16 insertions, 3 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 7fb04970c72d..27f5e3738a7b 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -647,11 +647,24 @@ find_page:
         }
 
         ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
-        if (ret == AOP_TRUNCATED_PAGE) {
+        if (unlikely(ret)) {
+                loff_t isize = i_size_read(mapping->host);
+
+                if (ret != AOP_TRUNCATED_PAGE)
+                        unlock_page(page);
                 page_cache_release(page);
-                goto find_page;
-        } else if (ret)
+                if (ret == AOP_TRUNCATED_PAGE)
+                        goto find_page;
+
+                /*
+                 * prepare_write() may have instantiated a few blocks
+                 * outside i_size.  Trim these off again.
+                 */
+                if (sd->pos + this_len > isize)
+                        vmtruncate(mapping->host, isize);
+
                 goto out;
+        }
 
         if (buf->page != page) {
                 /*