Bug#920886: btrfs-progs: btrfs send failed to determine mount point for snapshots stored in /

[Chris Lawrence]

Package: btrfs-progs
Followup-For: Bug #920886

Here's a properly formatted patch that fixes the bug; it appears to
work on my system at least.

-- System Information:
Debian Release: buster/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing'), (102, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.20.2 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), 
LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages btrfs-progs depends on:
ii  libblkid1  2.33.1-0.1
ii  libc6      2.28-5
ii  liblzo2-2  2.10-0.1
ii  libuuid1   2.33.1-0.1
ii  libzstd1   1.3.8+dfsg-3
ii  zlib1g     1:1.2.11.dfsg-1

btrfs-progs recommends no packages.

Versions of packages btrfs-progs suggests:
ii  duperemove  0.11.1-3

-- no debconf information

--- a/utils.c
+++ b/utils.c
@@ -2079,7 +2079,7 @@ int find_mount_root(const char *path, ch
        while ((ent = getmntent(mnttab))) {
                len = strlen(ent->mnt_dir);
                if (strncmp(ent->mnt_dir, path, len) == 0 &&
-                   (path[len] == '/' || path[len] == '\0')) {
+                   (len == 1 || path[len] == '/' || path[len] == '\0')) {
                        /* match found and use the latest match */
                        if (longest_matchlen <= len) {
                                free(longest_match);