udf: Protect default inode credentials by rwlock

Superblock carries credentials (uid, gid, etc.) which are used as default
values in __udf_read_inode() when media does not provide these. These
credentials can change during remount so we protect them by a rwlock so that
each inode gets a consistent set of credentials.

Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 9f38a6ca4fd5..4858c191242b 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -129,6 +129,8 @@ struct udf_sb_info {
         uid_t                   s_uid;
         mode_t                  s_fmode;
         mode_t                  s_dmode;
+        /* Lock protecting consistency of above permission settings */
+        rwlock_t                s_cred_lock;
 
         /* Root Info */
         struct timespec         s_record_time;