1 files changed, 21 insertions, 4 deletions

diff --git a/fs/xfs/xfs_sb.c b/fs/xfs/xfs_sb.c
index c3453b11f563..7703fa6770ff 100644
--- a/fs/xfs/xfs_sb.c
+++ b/fs/xfs/xfs_sb.c
@@ -483,10 +483,16 @@ xfs_sb_quota_to_disk(
         }
 
         /*
-         * GQUOTINO and PQUOTINO cannot be used together in versions
-         * of superblock that do not have pquotino. from->sb_flags
-         * tells us which quota is active and should be copied to
-         * disk.
+         * GQUOTINO and PQUOTINO cannot be used together in versions of
+         * superblock that do not have pquotino. from->sb_flags tells us which
+         * quota is active and should be copied to disk. If neither are active,
+         * make sure we write NULLFSINO to the sb_gquotino field as a quota
+         * inode value of "0" is invalid when the XFS_SB_VERSION_QUOTA feature
+         * bit is set.
+         *
+         * Note that we don't need to handle the sb_uquotino or sb_pquotino here
+         * as they do not require any translation. Hence the main sb field loop
+         * will write them appropriately from the in-core superblock.
          */
         if ((*fields & XFS_SB_GQUOTINO) &&
                                 (from->sb_qflags & XFS_GQUOTA_ACCT))
@@ -494,6 +500,17 @@ xfs_sb_quota_to_disk(
         else if ((*fields & XFS_SB_PQUOTINO) &&
                                 (from->sb_qflags & XFS_PQUOTA_ACCT))
                 to->sb_gquotino = cpu_to_be64(from->sb_pquotino);
+        else {
+                /*
+                 * We can't rely on just the fields being logged to tell us
+                 * that it is safe to write NULLFSINO - we should only do that
+                 * if quotas are not actually enabled. Hence only write
+                 * NULLFSINO if both in-core quota inodes are NULL.
+                 */
+                if (from->sb_gquotino == NULLFSINO &&
+                    from->sb_pquotino == NULLFSINO)
+                        to->sb_gquotino = cpu_to_be64(NULLFSINO);
+        }
 
         *fields &= ~(XFS_SB_PQUOTINO | XFS_SB_GQUOTINO);
 }