dm ioctl: forbid messages to devices being deleted

Once we begin deleting a device, prevent any further messages being sent
to targets of its table (to avoid races).

Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index bf3d19a0fb78..d06dd39856f3 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1303,6 +1303,11 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
         if (!table)
                 goto out_argv;
 
+        if (dm_deleting_md(md)) {
+                r = -ENXIO;
+                goto out_table;
+        }
+
         ti = dm_table_find_target(table, tmsg->sector);
         if (!dm_target_is_valid(ti)) {
                 DMWARN("Target message sector outside device.");
@@ -1314,6 +1319,7 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
                 r = -EINVAL;
         }
 
+ out_table:
         dm_table_put(table);
  out_argv:
         kfree(argv);