[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>

6 files changed, 33 insertions, 19 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index d6a031ed391b..86dc28c7aa5c 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -323,7 +323,8 @@ struct smb_version_operations {
         /* async read from the server */
         int (*async_readv)(struct cifs_readdata *);
         /* async write to the server */
-        int (*async_writev)(struct cifs_writedata *);
+        int (*async_writev)(struct cifs_writedata *,
+                            void (*release)(struct kref *));
         /* sync read from the server */
         int (*sync_read)(const unsigned int, struct cifsFileInfo *,
                          struct cifs_io_parms *, unsigned int *, char **,
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 79e6e9a93a8c..d00e09dfc452 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -488,7 +488,8 @@ void cifs_readdata_release(struct kref *refcount);
 int cifs_async_readv(struct cifs_readdata *rdata);
 int cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid);
 
-int cifs_async_writev(struct cifs_writedata *wdata);
+int cifs_async_writev(struct cifs_writedata *wdata,
+                      void (*release)(struct kref *kref));
 void cifs_writev_complete(struct work_struct *work);
 struct cifs_writedata *cifs_writedata_alloc(unsigned int nr_pages,
                                                 work_func_t complete);
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 0cd742ccb019..f3264bd7a83d 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1910,7 +1910,7 @@ cifs_writev_requeue(struct cifs_writedata *wdata)
 
         do {
                 server = tlink_tcon(wdata->cfile->tlink)->ses->server;
-                rc = server->ops->async_writev(wdata);
+                rc = server->ops->async_writev(wdata, cifs_writedata_release);
         } while (rc == -EAGAIN);
 
         for (i = 0; i < wdata->nr_pages; i++) {
@@ -2025,7 +2025,8 @@ cifs_writev_callback(struct mid_q_entry *mid)
 
 /* cifs_async_writev - send an async write, and set up mid to handle result */
 int
-cifs_async_writev(struct cifs_writedata *wdata)
+cifs_async_writev(struct cifs_writedata *wdata,
+                  void (*release)(struct kref *kref))
 {
         int rc = -EACCES;
         WRITE_REQ *smb = NULL;
@@ -2099,7 +2100,7 @@ cifs_async_writev(struct cifs_writedata *wdata)
         if (rc == 0)
                 cifs_stats_inc(&tcon->stats.cifs_stats.num_writes);
         else
-                kref_put(&wdata->refcount, cifs_writedata_release);
+                kref_put(&wdata->refcount, release);
 
 async_writev_out:
         cifs_small_buf_release(smb);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 853d6d1cc822..a301edbdad4a 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)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 2013234b73ad..a3f7a9c3cc69 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1890,7 +1890,8 @@ smb2_writev_callback(struct mid_q_entry *mid)
 
 /* smb2_async_writev - send an async write, and set up mid to handle result */
 int
-smb2_async_writev(struct cifs_writedata *wdata)
+smb2_async_writev(struct cifs_writedata *wdata,
+                  void (*release)(struct kref *kref))
 {
         int rc = -EACCES;
         struct smb2_write_req *req = NULL;
@@ -1938,7 +1939,7 @@ smb2_async_writev(struct cifs_writedata *wdata)
                                 smb2_writev_callback, wdata, 0);
 
         if (rc) {
-                kref_put(&wdata->refcount, cifs_writedata_release);
+                kref_put(&wdata->refcount, release);
                 cifs_stats_fail_inc(tcon, SMB2_WRITE_HE);
         }
 
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 93adc64666f3..0ce48db20a65 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -123,7 +123,8 @@ extern int SMB2_get_srv_num(const unsigned int xid, struct cifs_tcon *tcon,
 extern int smb2_async_readv(struct cifs_readdata *rdata);
 extern int SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
                      unsigned int *nbytes, char **buf, int *buf_type);
-extern int smb2_async_writev(struct cifs_writedata *wdata);
+extern int smb2_async_writev(struct cifs_writedata *wdata,
+                             void (*release)(struct kref *kref));
 extern int SMB2_write(const unsigned int xid, struct cifs_io_parms *io_parms,
                       unsigned int *nbytes, struct kvec *iov, int n_vec);
 extern int SMB2_echo(struct TCP_Server_Info *server);