From 896f937f58f42284dbebcd0a7f5ddc87fd5517b7 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 29 Sep 2017 14:19:22 +0200
Subject: [PATCH 1/3] dissect: automatically mark partitions read-only that
 have a read-only file system

Specifically, squashfs and iso9660 are always read-only, hence make sure
we never even think about mounting them writable.
---
 src/basic/mount-util.c     | 13 +++++++++++++
 src/basic/mount-util.h     |  1 +
 src/shared/dissect-image.c |  3 +++
 3 files changed, 17 insertions(+)

diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
index cff44116c8..843d266a2f 100644
--- a/src/basic/mount-util.c
+++ b/src/basic/mount-util.c
@@ -578,6 +578,19 @@ bool fstype_is_api_vfs(const char *fstype) {
         return nulstr_contains(table, fstype);
 }
 
+bool fstype_is_ro(const char *fstype) {
+
+        /* All Linux file systems that are necessarily read-only */
+
+        static const char table[] =
+                "DM_verity_hash\0"
+                "iso9660\0"
+                "squashfs\0"
+                ;
+
+        return nulstr_contains(table, fstype);
+}
+
 int repeat_unmount(const char *path, int flags) {
         bool done = false;
 
diff --git a/src/basic/mount-util.h b/src/basic/mount-util.h
index 70af11c2ff..3ec0e7d1f8 100644
--- a/src/basic/mount-util.h
+++ b/src/basic/mount-util.h
@@ -45,6 +45,7 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, endmntent);
 
 bool fstype_is_network(const char *fstype);
 bool fstype_is_api_vfs(const char *fstype);
+bool fstype_is_ro(const char *fsype);
 
 union file_handle_union {
         struct file_handle handle;
diff --git a/src/shared/dissect-image.c b/src/shared/dissect-image.c
index f11b522558..b02b2897d3 100644
--- a/src/shared/dissect-image.c
+++ b/src/shared/dissect-image.c
@@ -591,6 +591,9 @@ int dissect_image(int fd, const void *root_hash, size_t root_hash_size, DissectI
 
                 if (streq_ptr(p->fstype, "crypto_LUKS"))
                         m->encrypted = true;
+
+                if (p->fstype && fstype_is_ro(p->fstype))
+                        p->rw = false;
         }
 
         *ret = m;

From 154d22695ad6f131f0e2f99b895b3b1038c10eea Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 29 Sep 2017 14:23:17 +0200
Subject: [PATCH 2/3] dissect: split list of discard-supporting fs out into
 mount-util.c

Let's manage the list of file systems that do a specific thing at one
place, following similar naming.

No functional changes.
---
 src/basic/mount-util.c     | 12 ++++++++++++
 src/basic/mount-util.h     |  1 +
 src/shared/dissect-image.c |  2 +-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
index 843d266a2f..9069280721 100644
--- a/src/basic/mount-util.c
+++ b/src/basic/mount-util.c
@@ -591,6 +591,18 @@ bool fstype_is_ro(const char *fstype) {
         return nulstr_contains(table, fstype);
 }
 
+bool fstype_can_discard(const char *fstype) {
+
+        static const char table[] =
+                "btrfs\0"
+                "ext4\0"
+                "vfat\0"
+                "xfs\0"
+                ;
+
+        return nulstr_contains(table, fstype);
+}
+
 int repeat_unmount(const char *path, int flags) {
         bool done = false;
 
diff --git a/src/basic/mount-util.h b/src/basic/mount-util.h
index 3ec0e7d1f8..1e066d8886 100644
--- a/src/basic/mount-util.h
+++ b/src/basic/mount-util.h
@@ -46,6 +46,7 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(FILE*, endmntent);
 bool fstype_is_network(const char *fstype);
 bool fstype_is_api_vfs(const char *fstype);
 bool fstype_is_ro(const char *fsype);
+bool fstype_can_discard(const char *fstype);
 
 union file_handle_union {
         struct file_handle handle;
diff --git a/src/shared/dissect-image.c b/src/shared/dissect-image.c
index b02b2897d3..243a46f2e3 100644
--- a/src/shared/dissect-image.c
+++ b/src/shared/dissect-image.c
@@ -684,7 +684,7 @@ static int mount_partition(
                 p = where;
 
         /* If requested, turn on discard support. */
-        if (STR_IN_SET(fstype, "btrfs", "ext4", "vfat", "xfs") &&
+        if (fstype_can_discard(fstype) &&
             ((flags & DISSECT_IMAGE_DISCARD) ||
              ((flags & DISSECT_IMAGE_DISCARD_ON_LOOP) && is_loop_device(m->node))))
                 options = "discard";

From 7941e2189bf0a2118d4ad1fcf5ff2da534c3b67d Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 29 Sep 2017 14:36:06 +0200
Subject: [PATCH 3/3] mount-util: add fusectl to list of API VFS

---
 src/basic/mount-util.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
index 9069280721..8c1d2bc9c9 100644
--- a/src/basic/mount-util.c
+++ b/src/basic/mount-util.c
@@ -564,6 +564,7 @@ bool fstype_is_api_vfs(const char *fstype) {
                 "devpts\0"
                 "devtmpfs\0"
                 "efivarfs\0"
+                "fusectl\0"
                 "hugetlbfs\0"
                 "mqueue\0"
                 "proc\0"