ext4: add debugging trigger for ext4_error()

Make it easy to test whether or not the error handling subsystem in
ext4 is working correctly.  This allows us to simulate an ext4_error()
by echoing a string to /sys/fs/ext4/<dev>/trigger_fs_error.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: ksumrall@google.com

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 511011a1e85d..decc15d1b4b6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1197,6 +1197,7 @@ struct ext4_sb_info {
         struct proc_dir_entry *s_proc;
         struct kobject s_kobj;
         struct completion s_kobj_unregister;
+        struct super_block *s_sb;
 
         /* Journaling */
         struct journal_s *s_journal;