From 6c373810f5b1d32824371e9dff6ee5a006388f98 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Thu, 20 Feb 2014 16:59:11 +0100
Subject: [PATCH] libmount: FS id and parent ID could be zero
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It seems that linux 3.14 is able to produce things like:

  19 0 8:3 / / rw,relatime - ext4 /dev/sda3 rw,data=ordered
     ^

Reported-by: Mantas Mikulėnas <grawity@gmail.com>
Signed-off-by: Karel Zak <kzak@redhat.com>
---
 libmount/src/tab.c   | 12 ++++--------
 misc-utils/findmnt.c |  5 +++--
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/libmount/src/tab.c b/libmount/src/tab.c
index 4c2f8a4..332312b 100644
--- a/libmount/src/tab.c
+++ b/libmount/src/tab.c
@@ -505,7 +505,7 @@ int mnt_table_get_root_fs(struct libmnt_table *tb, struct libmnt_fs **root)
 	assert(tb);
 	assert(root);
 
-	if (!tb || !root)
+	if (!tb || !root || !is_mountinfo(tb))
 		return -EINVAL;
 
 	DBG(TAB, mnt_debug_h(tb, "lookup root fs"));
@@ -515,8 +515,6 @@ int mnt_table_get_root_fs(struct libmnt_table *tb, struct libmnt_fs **root)
 	mnt_reset_iter(&itr, MNT_ITER_FORWARD);
 	while(mnt_table_next_fs(tb, &itr, &fs) == 0) {
 		int id = mnt_fs_get_parent_id(fs);
-		if (!id)
-			break;		/* @tab is not a mountinfo file? */
 
 		if (!*root || id < root_id) {
 			*root = fs;
@@ -524,7 +522,7 @@ int mnt_table_get_root_fs(struct libmnt_table *tb, struct libmnt_fs **root)
 		}
 	}
 
-	return root_id ? 0 : -EINVAL;
+	return *root ? 0 : -EINVAL;
 }
 
 /**
@@ -545,15 +543,13 @@ int mnt_table_next_child_fs(struct libmnt_table *tb, struct libmnt_iter *itr,
 	struct libmnt_fs *fs;
 	int parent_id, lastchld_id = 0, chld_id = 0;
 
-	if (!tb || !itr || !parent)
+	if (!tb || !itr || !parent || !is_mountinfo(tb))
 		return -EINVAL;
 
 	DBG(TAB, mnt_debug_h(tb, "lookup next child of '%s'",
 				mnt_fs_get_target(parent)));
 
 	parent_id = mnt_fs_get_id(parent);
-	if (!parent_id)
-		return -EINVAL;
 
 	/* get ID of the previously returned child */
 	if (itr->head && itr->p != itr->head) {
@@ -584,7 +580,7 @@ int mnt_table_next_child_fs(struct libmnt_table *tb, struct libmnt_iter *itr,
 		}
 	}
 
-	if (!chld_id)
+	if (!*chld)
 		return 1;	/* end of iterator */
 
 	/* set the iterator to the @chld for the next call */
diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c
index fb21174..988cd73 100644
--- a/misc-utils/findmnt.c
+++ b/misc-utils/findmnt.c
@@ -822,8 +822,9 @@ static int tab_is_tree(struct libmnt_table *tb)
 	if (!itr)
 		return 0;
 
-	if (mnt_table_next_fs(tb, itr, &fs) == 0)
-		rc = mnt_fs_get_id(fs) > 0 && mnt_fs_get_parent_id(fs) > 0;
+	rc = (mnt_table_next_fs(tb, itr, &fs) == 0 &&
+	      mnt_fs_is_kernel(fs) &&
+	      mnt_fs_get_root(fs));
 
 	mnt_free_iter(itr);
 	return rc;
-- 
1.9.1

