GNU bug report logs - #49298
[PATCH] df: do not print duplicated entires with NFS and bind mounts

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Package: coreutils;

Reported by: Kamil Dudka <kdudka <at> redhat.com>

Date: Wed, 30 Jun 2021 15:54:01 UTC

Severity: normal

Tags: patch

Done: Pádraig Brady <P <at> draigBrady.com>

Bug is archived. No further changes may be made.

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Pádraig Brady <P <at> draigBrady.com>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#49298: closed ([PATCH] df: do not print duplicated entires
 with NFS and bind mounts)
Date: Fri, 02 Jul 2021 15:08:02 +0000
[Message part 1 (text/plain, inline)]
Your message dated Fri, 2 Jul 2021 16:07:38 +0100
with message-id <bc9c9ef4-cb2b-0d39-da7a-e8a42c0a6e06 <at> draigBrady.com>
and subject line Re: bug#49298: [PATCH] df: do not print duplicated entires with NFS and bind mounts
has caused the debbugs.gnu.org bug report #49298,
regarding [PATCH] df: do not print duplicated entires with NFS and bind mounts
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


-- 
49298: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=49298
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems
[Message part 2 (message/rfc822, inline)]
From: Kamil Dudka <kdudka <at> redhat.com>
To: bug-coreutils <at> gnu.org
Subject: [PATCH] df: do not print duplicated entires with NFS and bind mounts
Date: Wed, 30 Jun 2021 17:53:22 +0200
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.
---
 src/df.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/df.c b/src/df.c
index aadc3483f22..16a7b5524df 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
@@ -681,7 +682,13 @@ 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
@@ -799,8 +806,12 @@ 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 *inserted = hash_insert (devlist_table, devlist);
+          if (inserted == NULL)
             xalloc_die ();
+          /* Remember the last devlist entry we have seen with this dev_num */
+          inserted->seen_last = devlist;
 
           me = me->me_next;
         }
-- 
2.31.1



[Message part 3 (message/rfc822, inline)]
From: Pádraig Brady <P <at> draigBrady.com>
To: Kamil Dudka <kdudka <at> redhat.com>, 49298-done <at> debbugs.gnu.org
Subject: Re: bug#49298: [PATCH] df: do not print duplicated entires with NFS
 and bind mounts
Date: Fri, 2 Jul 2021 16:07:38 +0100
On 30/06/2021 16:53, Kamil Dudka wrote:
> 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.


Indeed order is significant here as we can have multiple entries for the same dev nums.
The patch looks good and restores the ordering from before commit 1c17f61ef.
I'll will apply this.
Marking as done.

thanks!
Pádraig


This bug report was last modified 4 years ago.

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