From 6a3bbccab6f8262912bdc2cf5bff77553c547e30 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
Date: Thu, 25 Nov 2010 15:48:27 +0100
Subject: [PATCH] Use /proc/mounts for mountpoint scanning

This is back-port of relevant part of upstream commit
d271d0a329a5b3e99f4ad209b5270a8648739ff0.

Series of switching quota on/off by mount(8) command (-o remount,noquota
-o remount,usrquota,grpquota) damages /etc/mtab content
(usrquota,grpquota,noquota,usrquota,grpquota) and that makes quota to
believe the mount point has quota off.

See <https://bugzilla.redhat.com/show_bug.cgi?id=623656> for more details.
---
 configure.in |    7 +++++++
 quotasys.c   |   23 +++++++++++++----------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/configure.in b/configure.in
index c119c6c..58c1c62 100644
--- a/configure.in
+++ b/configure.in
@@ -205,6 +205,10 @@ AC_ARG_ENABLE(rootsbin,
 	[  --enable-rootsbin=[yes/no]      Use /sbin for some important binaries regardless $prefix [default=no].],
 	,
 	enable_rootsbin="no")
+AC_ARG_ENABLE(proc-mounts,
+	[  --enable-proc-mounts=[path]   Use alternate file instead of /etc/mtab [default=/proc/mounts].],
+	,
+	enable_proc_mounts="/proc/mounts")
 
 if test "$enable_altformat" = "yes" ; then
 	CFLAGS="-DALT_FORMAT $CFLAGS"
@@ -233,6 +237,9 @@ if test "$enable_nls" = "yes" ; then
 	CFLAGS="-D__GETTEXT__ $CFLAGS"
 	INSTMO="inst_mo"
 fi
+if test -n "$enable_proc_mounts" ; then
+	CFLAGS="-DALT_MTAB=\\\"$enable_proc_mounts\\\" $CFLAGS"
+fi
 if test "$enable_rootsbin" = "yes" ; then
 	ROOTSBIN="/sbin"
 else
diff --git a/quotasys.c b/quotasys.c
index 86802c3..dbe9d1c 100644
--- a/quotasys.c
+++ b/quotasys.c
@@ -913,17 +913,20 @@ static int cache_mnt_table(int flags)
 	int autofsdircnt = 0;
 	char autofsdir[AUTOFS_DIR_MAX][PATH_MAX];
 
-	if (!(mntf = setmntent(_PATH_MOUNTED, "r"))) {
-		if (errno != ENOENT) {
-			errstr(_("Cannot open %s: %s\n"), _PATH_MOUNTED, strerror(errno));
-			return -1;
-		}
-		else	/* Fallback on fstab when mtab not available */
-			if (!(mntf = setmntent(_PATH_MNTTAB, "r"))) {
-				errstr(_("Cannot open %s: %s\n"), _PATH_MNTTAB, strerror(errno));
-				return -1;
-			}
+#ifdef ALT_MTAB
+	mntf = setmntent(ALT_MTAB, "r");
+	if (mntf)
+		goto alloc;
+#endif
+	mntf = setmntent(_PATH_MOUNTED, "r");
+	if (mntf)
+		goto alloc;
+	/* Fallback to fstab when mtab not available */
+	if (!(mntf = setmntent(_PATH_MNTTAB, "r"))) {
+		errstr(_("Cannot open any file with mount points.\n"));
+		return -1;
 	}
+alloc:
 	mnt_entries = smalloc(sizeof(struct mount_entry) * ALLOC_ENTRIES_NUM);
 	mnt_entries_cnt = 0;
 	allocated += ALLOC_ENTRIES_NUM;
-- 
1.7.3.2