dm resume: don't return EINVAL when signalled

If the dm_resume method is called on a device that is not suspended, the
method will suspend the device briefly, before resuming it (so that the
table will be swapped).

However, there was a bug that the return value of dm_suspended_md was not
checked. dm_suspended_md may return an error when it is interrupted by a
signal. In this case, do_resume would call dm_swap_table, which would
return -EINVAL.

This commit fixes the logic, so that error returned by dm_suspend is
checked and the resume operation is undone.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index c2c07bfa647199139f78522c5c87da3e170e6cee..f299ff393a6a2ceda77bcc566f4d121123d9508c 100644 (file)
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1181,8 +1181,26 @@ static int do_resume(struct dm_ioctl *param)
                        suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
                if (param->flags & DM_NOFLUSH_FLAG)
                        suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
-               if (!dm_suspended_md(md))
-                       dm_suspend(md, suspend_flags);
+               if (!dm_suspended_md(md)) {
+                       r = dm_suspend(md, suspend_flags);
+                       if (r) {
+                               down_write(&_hash_lock);
+                               hc = dm_get_mdptr(md);
+                               if (hc && !hc->new_map) {
+                                       hc->new_map = new_map;
+                                       new_map = NULL;
+                               } else {
+                                       r = -ENXIO;
+                               }
+                               up_write(&_hash_lock);
+                               if (new_map) {
+                                       dm_sync_table(md);
+                                       dm_table_destroy(new_map);
+                               }
+                               dm_put(md);
+                               return r;
+                       }
+               }
 
                old_size = dm_get_size(md);
                old_map = dm_swap_table(md, new_map);