From 3ab4ef3ca9bf77b7dbb924fa75dcc9f7c6c3ea59 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Mon, 22 Mar 2021 14:58:05 +0100
Subject: [PATCH] findmnt: add --shadowed

Signed-off-by: Karel Zak <kzak@redhat.com>
---
 misc-utils/findmnt.8 |  3 +++
 misc-utils/findmnt.c | 16 +++++++++++++++-
 misc-utils/findmnt.h | 13 +++++++------
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/misc-utils/findmnt.8 b/misc-utils/findmnt.8
index c93c01c20..658dda9eb 100644
--- a/misc-utils/findmnt.8
+++ b/misc-utils/findmnt.8
@@ -193,6 +193,9 @@ available for umount and remount actions
 .B \-\-pseudo
 Print only pseudo filesystems.
 .TP
+.B \-\-shadowed
+Print only filesystems over-mounted by another filesystem.
+.TP
 .BR \-R , " \-\-submounts"
 Print recursively all submounts for the selected filesystems.  The restrictions
 defined by options \fB\-t\fP, \fB\-O\fP, \fB\-S\fP, \fB\-T\fP and
diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c
index 774c059de..a1c692535 100644
--- a/misc-utils/findmnt.c
+++ b/misc-utils/findmnt.c
@@ -970,6 +970,14 @@ static int match_func(struct libmnt_fs *fs,
 	if ((flags & FL_PSEUDO) && !mnt_fs_is_pseudofs(fs))
 	    return rc;
 
+	if ((flags & FL_SHADOWED)) {
+		struct libmnt_table *tb = NULL;
+
+		mnt_fs_get_table(fs, &tb);
+		if (tb && mnt_table_over_fs(tb, fs, NULL) != 0)
+			return rc;
+	}
+
 	return !rc;
 }
 
@@ -1254,6 +1262,7 @@ static void __attribute__((__noreturn__)) usage(void)
 	fputs(_("     --output-all       output all available columns\n"), out);
 	fputs(_(" -P, --pairs            use key=\"value\" output format\n"), out);
 	fputs(_("     --pseudo           print only pseudo-filesystems\n"), out);
+	fputs(_("     --shadowed         print only filesystems over-mounted by another filesystem\n"), out);
 	fputs(_(" -R, --submounts        print all submounts for the matching filesystems\n"), out);
 	fputs(_(" -r, --raw              use raw output format\n"), out);
 	fputs(_("     --real             print only real filesystems\n"), out);
@@ -1304,7 +1313,8 @@ int main(int argc, char *argv[])
 		FINDMNT_OPT_OUTPUT_ALL,
 		FINDMNT_OPT_PSEUDO,
 		FINDMNT_OPT_REAL,
-		FINDMNT_OPT_VFS_ALL
+		FINDMNT_OPT_VFS_ALL,
+		FINDMNT_OPT_SHADOWED
 	};
 
 	static const struct option longopts[] = {
@@ -1349,6 +1359,7 @@ int main(int argc, char *argv[])
 		{ "real",	    no_argument,       NULL, FINDMNT_OPT_REAL	 },
 		{ "pseudo",	    no_argument,       NULL, FINDMNT_OPT_PSEUDO	 },
 		{ "vfs-all",	    no_argument,       NULL, FINDMNT_OPT_VFS_ALL },
+		{ "shadowed",       no_argument,       NULL, FINDMNT_OPT_SHADOWED },
 		{ NULL, 0, NULL, 0 }
 	};
 
@@ -1526,6 +1537,9 @@ int main(int argc, char *argv[])
 		case FINDMNT_OPT_VFS_ALL:
 			flags |= FL_VFS_ALL;
 			break;
+		case FINDMNT_OPT_SHADOWED:
+			flags |= FL_SHADOWED;
+			break;
 
 		case 'h':
 			usage();
diff --git a/misc-utils/findmnt.h b/misc-utils/findmnt.h
index 92d1119ae..ed7dea05a 100644
--- a/misc-utils/findmnt.h
+++ b/misc-utils/findmnt.h
@@ -21,14 +21,15 @@ enum {
 	FL_PSEUDO	= (1 << 17),
 	FL_REAL		= (1 << 18),
 	FL_VFS_ALL	= (1 << 19),
+	FL_SHADOWED	= (1 << 20),
 
 	/* basic table settings */
-	FL_ASCII	= (1 << 20),
-	FL_RAW		= (1 << 21),
-	FL_NOHEADINGS	= (1 << 22),
-	FL_EXPORT	= (1 << 23),
-	FL_TREE		= (1 << 24),
-	FL_JSON		= (1 << 25),
+	FL_ASCII	= (1 << 21),
+	FL_RAW		= (1 << 22),
+	FL_NOHEADINGS	= (1 << 23),
+	FL_EXPORT	= (1 << 24),
+	FL_TREE		= (1 << 25),
+	FL_JSON		= (1 << 26),
 };
 
 extern struct libmnt_cache *cache;