LU-4863 lloop: avoid panic during blockdev_info

Change the LL_IOC_LLOOP_INFO ioctl in the lustre lloop
device driver to return an error instead of causing
panics with LASSERT().

Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: Ib50afa94960dee6fb580038d6e96ea648252d9ea
Reviewed-on: http://review.whamcloud.com/9888
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>

diff --git a/lustre/llite/lloop.c b/lustre/llite/lloop.c
index cef0de6..90bf646 100644 (file)
--- a/lustre/llite/lloop.c
+++ b/lustre/llite/lloop.c
@@ -645,7 +645,10 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
         case LL_IOC_LLOOP_INFO: {
                 struct lu_fid fid;
 
         case LL_IOC_LLOOP_INFO: {
                 struct lu_fid fid;
 

-                LASSERT(lo->lo_backing_file != NULL);
+               if (lo->lo_backing_file == NULL) {
+                       err = -ENOENT;
+                       break;
+               }

                 if (inode == NULL)
                         inode = lo->lo_backing_file->f_dentry->d_inode;
                 if (lo->lo_state == LLOOP_BOUND)
                 if (inode == NULL)
                         inode = lo->lo_backing_file->f_dentry->d_inode;
                 if (lo->lo_state == LLOOP_BOUND)