[CIFS] clean up page array when uncached write send fails

In the event that a send fails in an uncached write, or we end up
needing to reissue it (-EAGAIN case), we'll kfree the wdata but
the pages currently leak.

Fix this by adding a new kref release routine for uncached writedata
that releases the pages, and have the uncached codepaths use that.

[original patch by Jeff modified to fix minor formatting problems]

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 20 insertions, 11 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 853d6d1..a301edb 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2043,7 +2043,8 @@ retry:
 			}
 			wdata->pid = wdata->cfile->pid;
 			server = tlink_tcon(wdata->cfile->tlink)->ses->server;
-			rc = server->ops->async_writev(wdata);
+			rc = server->ops->async_writev(wdata,
+							cifs_writedata_release);
 		} while (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN);
 
 		for (i = 0; i < nr_pages; ++i)
@@ -2331,9 +2332,20 @@ size_t get_numpages(const size_t wsize, const size_t len, size_t *cur_len)
 }
 
 static void
-cifs_uncached_writev_complete(struct work_struct *work)
+cifs_uncached_writedata_release(struct kref *refcount)
 {
 	int i;
+	struct cifs_writedata *wdata = container_of(refcount,
+					struct cifs_writedata, refcount);
+
+	for (i = 0; i < wdata->nr_pages; i++)
+		put_page(wdata->pages[i]);
+	cifs_writedata_release(refcount);
+}
+
+static void
+cifs_uncached_writev_complete(struct work_struct *work)
+{
 	struct cifs_writedata *wdata = container_of(work,
 					struct cifs_writedata, work);
 	struct inode *inode = wdata->cfile->dentry->d_inode;
@@ -2347,12 +2359,7 @@ cifs_uncached_writev_complete(struct work_struct *work)
 
 	complete(&wdata->done);
 
-	if (wdata->result != -EAGAIN) {
-		for (i = 0; i < wdata->nr_pages; i++)
-			put_page(wdata->pages[i]);
-	}
-
-	kref_put(&wdata->refcount, cifs_writedata_release);
+	kref_put(&wdata->refcount, cifs_uncached_writedata_release);
 }
 
 /* attempt to send write to server, retry on any -EAGAIN errors */
@@ -2370,7 +2377,8 @@ cifs_uncached_retry_writev(struct cifs_writedata *wdata)
 			if (rc != 0)
 				continue;
 		}
-		rc = server->ops->async_writev(wdata);
+		rc = server->ops->async_writev(wdata,
+					       cifs_uncached_writedata_release);
 	} while (rc == -EAGAIN);
 
 	return rc;
@@ -2454,7 +2462,8 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
 		wdata->tailsz = cur_len - ((nr_pages - 1) * PAGE_SIZE);
 		rc = cifs_uncached_retry_writev(wdata);
 		if (rc) {
-			kref_put(&wdata->refcount, cifs_writedata_release);
+			kref_put(&wdata->refcount,
+				 cifs_uncached_writedata_release);
 			break;
 		}
 
@@ -2496,7 +2505,7 @@ restart_loop:
 			}
 		}
 		list_del_init(&wdata->list);
-		kref_put(&wdata->refcount, cifs_writedata_release);
+		kref_put(&wdata->refcount, cifs_uncached_writedata_release);
 	}
 
 	if (total_written > 0)