fs_mgr: clean up dm ioctl flags

DM_READONLY_FLAG should only be used when loading tables, and
DM_STATUS_TABLE_FLAG should only be used when querying a table's status. This
patch cleans up how we set flags to reflect when the kernel actually cares
about them.

Bug: 78914864
Test: AVB device still boots

Change-Id: I809d8c2ef2105849ebdd095bbe7f08f15ae63465

fs_mgr/fs_mgr.cpp

@@ -1383,7 +1383,7 @@ bool fs_mgr_update_verity_state(fs_mgr_verity_state_callback callback) {
             mount_point = basename(fstab->recs[i].mount_point);
         }
 
-        fs_mgr_verity_ioctl_init(io, mount_point, 0);
+        fs_mgr_verity_ioctl_init(io, mount_point);
 
         const char* status;
         if (ioctl(fd, DM_TABLE_STATUS, io)) {

fs_mgr/fs_mgr_avb.cpp

@@ -303,13 +303,14 @@ static std::string construct_verity_table(const AvbHashtreeDescriptor& hashtree_
 
 static bool load_verity_table(struct dm_ioctl* io, const std::string& dm_device_name, int fd,
                               uint64_t image_size, const std::string& verity_table) {
-    fs_mgr_verity_ioctl_init(io, dm_device_name, DM_STATUS_TABLE_FLAG);
+    fs_mgr_verity_ioctl_init(io, dm_device_name);
 
     // The buffer consists of [dm_ioctl][dm_target_spec][verity_params].
     char* buffer = (char*)io;
 
     // Builds the dm_target_spec arguments.
     struct dm_target_spec* dm_target = (struct dm_target_spec*)&buffer[sizeof(struct dm_ioctl)];
+    io->flags = DM_READONLY_FLAG;
     io->target_count = 1;
     dm_target->status = 0;
     dm_target->sector_start = 0;

fs_mgr/fs_mgr_dm_ioctl.cpp

@@ -23,21 +23,20 @@
 #include "fs_mgr_priv.h"
 #include "fs_mgr_priv_dm_ioctl.h"
 
-void fs_mgr_verity_ioctl_init(struct dm_ioctl* io, const std::string& name, unsigned flags) {
+void fs_mgr_verity_ioctl_init(struct dm_ioctl* io, const std::string& name) {
     memset(io, 0, DM_BUF_SIZE);
     io->data_size = DM_BUF_SIZE;
     io->data_start = sizeof(struct dm_ioctl);
     io->version[0] = 4;
     io->version[1] = 0;
     io->version[2] = 0;
-    io->flags = flags | DM_READONLY_FLAG;
     if (!name.empty()) {
         strlcpy(io->name, name.c_str(), sizeof(io->name));
     }
 }
 
 bool fs_mgr_create_verity_device(struct dm_ioctl* io, const std::string& name, int fd) {
-    fs_mgr_verity_ioctl_init(io, name, 1);
+    fs_mgr_verity_ioctl_init(io, name);
     if (ioctl(fd, DM_DEV_CREATE, io)) {
         PERROR << "Error creating device mapping";
         return false;
@@ -46,7 +45,7 @@ bool fs_mgr_create_verity_device(struct dm_ioctl* io, const std::string& name, i
 }
 
 bool fs_mgr_destroy_verity_device(struct dm_ioctl* io, const std::string& name, int fd) {
-    fs_mgr_verity_ioctl_init(io, name, 0);
+    fs_mgr_verity_ioctl_init(io, name);
     if (ioctl(fd, DM_DEV_REMOVE, io)) {
         PERROR << "Error removing device mapping";
         return false;
@@ -58,7 +57,7 @@ bool fs_mgr_get_verity_device_name(struct dm_ioctl* io, const std::string& name,
                                    std::string* out_dev_name) {
     FS_MGR_CHECK(out_dev_name != nullptr);
 
-    fs_mgr_verity_ioctl_init(io, name, 0);
+    fs_mgr_verity_ioctl_init(io, name);
     if (ioctl(fd, DM_DEV_STATUS, io)) {
         PERROR << "Error fetching verity device number";
         return false;
@@ -71,7 +70,7 @@ bool fs_mgr_get_verity_device_name(struct dm_ioctl* io, const std::string& name,
 }
 
 bool fs_mgr_resume_verity_table(struct dm_ioctl* io, const std::string& name, int fd) {
-    fs_mgr_verity_ioctl_init(io, name, 0);
+    fs_mgr_verity_ioctl_init(io, name);
     if (ioctl(fd, DM_DEV_SUSPEND, io)) {
         PERROR << "Error activating verity device";
         return false;

fs_mgr/fs_mgr_priv_dm_ioctl.h

@@ -20,7 +20,7 @@
 #include <linux/dm-ioctl.h>
 #include <string>
 
-void fs_mgr_verity_ioctl_init(struct dm_ioctl* io, const std::string& name, unsigned flags);
+void fs_mgr_verity_ioctl_init(struct dm_ioctl* io, const std::string& name);
 
 bool fs_mgr_create_verity_device(struct dm_ioctl* io, const std::string& name, int fd);
 

fs_mgr/fs_mgr_verity.cpp

@@ -258,12 +258,13 @@ static int load_verity_table(struct dm_ioctl *io, const std::string &name,
     char *buffer = (char*) io;
     size_t bufsize;
 
-    fs_mgr_verity_ioctl_init(io, name, DM_STATUS_TABLE_FLAG);
+    fs_mgr_verity_ioctl_init(io, name);
 
     struct dm_target_spec *tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)];
 
     // set tgt arguments
     io->target_count = 1;
+    io->flags = DM_READONLY_FLAG;
     tgt->status = 0;
     tgt->sector_start = 0;
     tgt->length = device_size / 512;