From 0f053de4bc3ca0cfd88a42d236881dfdddb10ee9 Mon Sep 17 00:00:00 2001
From: Kamil Dudka <kdudka@redhat.com>
Date: Wed, 30 Jun 2021 17:53:22 +0200
Subject: [PATCH] df: fix duplicated remote entries due to bind mounts

As originally reported in <https://bugzilla.redhat.com/1962515>,
df invoked without -a printed duplicated entries for NFS mounts
of bind mounts.  This is a regression from commit v8.25-54-g1c17f61ef99,
which introduced the use of a hash table.

The proposed patch makes sure that the devlist entry seen the last time
is used for comparison when eliminating duplicated mount entries.  This
way it worked before introducing the hash table.

Patch co-authored by Roberto Bergantinos.

* src/ls.c (struct devlist): Introduce the seen_last pointer.
(devlist_for_dev): Return the devlist entry seen the last time if found.
(filter_mount_list): Remember the devlist entry seen the last time for
each hashed item.
Fixes https://bugs.gnu.org/49298

Upstream-commit: d6125af095c9553f38cba0696f15158f5abe4ecc
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
 src/df.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/df.c b/src/df.c
index 7e01839..3e9247f 100644
--- a/src/df.c
+++ b/src/df.c
@@ -54,6 +54,7 @@ struct devlist
   dev_t dev_num;
   struct mount_entry *me;
   struct devlist *next;
+  struct devlist *seen_last; /* valid for hashed devlist entries only */
 };
 
 /* Filled with device numbers of examined file systems to avoid
@@ -689,7 +690,13 @@ devlist_for_dev (dev_t dev)
     return NULL;
   struct devlist dev_entry;
   dev_entry.dev_num = dev;
-  return hash_lookup (devlist_table, &dev_entry);
+
+  struct devlist *found = hash_lookup (devlist_table, &dev_entry);
+  if (found == NULL)
+    return NULL;
+
+  /* Return the last devlist entry we have seen with this dev_num */
+  return found->seen_last;
 }
 
 static void
@@ -807,8 +814,12 @@ filter_mount_list (bool devices_only)
           devlist->dev_num = buf.st_dev;
           devlist->next = device_list;
           device_list = devlist;
-          if (hash_insert (devlist_table, devlist) == NULL)
+
+          struct devlist *hash_entry = hash_insert (devlist_table, devlist);
+          if (hash_entry == NULL)
             xalloc_die ();
+          /* Ensure lookups use this latest devlist.  */
+          hash_entry->seen_last = devlist;
 
           me = me->me_next;
         }
-- 
2.31.1