File grub2-btrfs-04-subvol-mount.patch of Package trustedgrub2
Index: trustedgrub2-2.02~beta2/grub-core/fs/btrfs.c
===================================================================
--- trustedgrub2-2.02~beta2.orig/grub-core/fs/btrfs.c
+++ trustedgrub2-2.02~beta2/grub-core/fs/btrfs.c
@@ -32,6 +32,7 @@
#include <grub/command.h>
#include <grub/env.h>
#include <grub/extcmd.h>
+#include <grub/list.h>
GRUB_MOD_LICENSE ("GPLv3+");
@@ -245,6 +246,12 @@ static grub_err_t
grub_btrfs_read_logical (struct grub_btrfs_data *data,
grub_disk_addr_t addr, void *buf, grub_size_t size,
int recursion_depth);
+static grub_err_t
+get_root (struct grub_btrfs_data *data, struct grub_btrfs_key *key,
+ grub_uint64_t *tree, grub_uint8_t *type);
+
+grub_uint64_t
+find_mtab_subvol_tree (const char *path, char **path_in_subvol);
static grub_err_t
read_sblock (grub_disk_t disk, struct grub_btrfs_superblock *sb)
@@ -887,9 +894,26 @@ lookup_root_by_name(struct grub_btrfs_da
grub_err_t err;
grub_uint64_t tree = 0;
grub_uint8_t type;
+ grub_uint64_t saved_tree;
struct grub_btrfs_key key;
+ if (path[0] == '\0')
+ {
+ data->fs_tree = 0;
+ return GRUB_ERR_NONE;
+ }
+
+ err = get_root (data, &key, &tree, &type);
+ if (err)
+ return err;
+
+ saved_tree = data->fs_tree;
+ data->fs_tree = tree;
+
err = find_path (data, path, &key, &tree, &type);
+
+ data->fs_tree = saved_tree;
+
if (err)
return grub_error(GRUB_ERR_FILE_NOT_FOUND, "couldn't locate %s\n", path);
@@ -1758,11 +1782,20 @@ grub_btrfs_dir (grub_device_t device, co
int r = 0;
grub_uint64_t tree;
grub_uint8_t type;
+ char *new_path = NULL;
if (!data)
return grub_errno;
- err = find_path (data, path, &key_in, &tree, &type);
+ tree = find_mtab_subvol_tree (path, &new_path);
+
+ if (tree)
+ data->fs_tree = tree;
+
+ err = find_path (data, new_path ? new_path : path, &key_in, &tree, &type);
+ if (new_path)
+ grub_free (new_path);
+
if (err)
{
grub_btrfs_unmount (data);
@@ -1864,11 +1897,21 @@ grub_btrfs_open (struct grub_file *file,
struct grub_btrfs_inode inode;
grub_uint8_t type;
struct grub_btrfs_key key_in;
+ grub_uint64_t tree;
+ char *new_path = NULL;
if (!data)
return grub_errno;
- err = find_path (data, name, &key_in, &data->tree, &type);
+ tree = find_mtab_subvol_tree (name, &new_path);
+
+ if (tree)
+ data->fs_tree = tree;
+
+ err = find_path (data, new_path ? new_path : name, &key_in, &data->tree, &type);
+ if (new_path)
+ grub_free (new_path);
+
if (err)
{
grub_btrfs_unmount (data);
@@ -2039,6 +2082,150 @@ grub_cmd_btrfs_info (grub_command_t cmd
return 0;
}
+struct grub_btrfs_mtab
+{
+ struct grub_btrfs_mtab *next;
+ struct grub_btrfs_mtab **prev;
+ char *path;
+ char *subvol;
+ grub_uint64_t tree;
+};
+
+typedef struct grub_btrfs_mtab* grub_btrfs_mtab_t;
+
+static struct grub_btrfs_mtab *btrfs_mtab;
+
+#define FOR_GRUB_MTAB(var) FOR_LIST_ELEMENTS (var, btrfs_mtab)
+#define FOR_GRUB_MTAB_SAFE(var, next) FOR_LIST_ELEMENTS_SAFE((var), (next), btrfs_mtab)
+
+static void
+add_mountpoint (const char *path, const char *subvol, grub_uint64_t tree)
+{
+ grub_btrfs_mtab_t m = grub_malloc (sizeof (*m));
+
+ m->path = grub_strdup (path);
+ m->subvol = grub_strdup (subvol);
+ m->tree = tree;
+ grub_list_push (GRUB_AS_LIST_P (&btrfs_mtab), GRUB_AS_LIST (m));
+}
+
+static grub_err_t
+grub_cmd_btrfs_mount_subvol (grub_command_t cmd __attribute__ ((unused)), int argc,
+ char **argv)
+{
+ char *devname, *dirname, *subvol;
+ struct grub_btrfs_key key_in;
+ grub_uint8_t type;
+ grub_uint64_t tree;
+ grub_uint64_t saved_tree;
+ grub_err_t err;
+ struct grub_btrfs_data *data = NULL;
+ grub_device_t dev = NULL;
+
+ if (argc < 3)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, "required <dev> <dir> and <subvol>");
+
+ devname = grub_file_get_device_name(argv[0]);
+ dev = grub_device_open (devname);
+ grub_free (devname);
+
+ if (!dev)
+ {
+ err = grub_errno;
+ goto err_out;
+ }
+
+ dirname = argv[1];
+ subvol = argv[2];
+
+ data = grub_btrfs_mount (dev);
+ if (!data)
+ {
+ err = grub_errno;
+ goto err_out;
+ }
+
+ err = find_path (data, dirname, &key_in, &tree, &type);
+ if (err)
+ goto err_out;
+
+ if (type != GRUB_BTRFS_DIR_ITEM_TYPE_DIRECTORY)
+ {
+ err = grub_error (GRUB_ERR_BAD_FILE_TYPE, N_("not a directory"));
+ goto err_out;
+ }
+
+ err = get_root (data, &key_in, &tree, &type);
+
+ if (err)
+ goto err_out;
+
+ saved_tree = data->fs_tree;
+ data->fs_tree = tree;
+ err = find_path (data, subvol, &key_in, &tree, &type);
+ data->fs_tree = saved_tree;
+
+ if (err)
+ goto err_out;
+
+ if (key_in.object_id != grub_cpu_to_le64_compile_time (GRUB_BTRFS_OBJECT_ID_CHUNK) || tree == 0)
+ {
+ err = grub_error (GRUB_ERR_BAD_FILE_TYPE, "%s: not a subvolume\n", subvol);
+ goto err_out;
+ }
+
+ grub_btrfs_unmount (data);
+ grub_device_close (dev);
+ add_mountpoint (dirname, subvol, tree);
+
+ return GRUB_ERR_NONE;
+
+err_out:
+
+ if (data)
+ grub_btrfs_unmount (data);
+
+ if (dev)
+ grub_device_close (dev);
+
+ return err;
+}
+
+grub_uint64_t
+find_mtab_subvol_tree (const char *path, char **path_in_subvol)
+{
+ grub_btrfs_mtab_t m, cm;
+ grub_uint64_t tree;
+
+ if (!path || !path_in_subvol)
+ return 0;
+
+ *path_in_subvol = NULL;
+ tree = 0;
+ cm = NULL;
+
+ FOR_GRUB_MTAB (m)
+ {
+ if (grub_strncmp (path, m->path, grub_strlen (m->path)) == 0)
+ {
+ if (!cm)
+ cm = m;
+ else
+ if (grub_strcmp (m->path, cm->path) > 0)
+ cm = m;
+ }
+ }
+
+ if (cm)
+ {
+ const char *s = path + grub_strlen (cm->path);
+ *path_in_subvol = (s[0] == '\0') ? grub_strdup ("/") : grub_strdup (s);
+ tree = cm->tree;
+ }
+
+ return tree;
+}
+
static grub_err_t
get_fs_root(struct grub_btrfs_data *data, grub_uint64_t tree,
grub_uint64_t objectid, grub_uint64_t offset,
@@ -2245,6 +2432,7 @@ static struct grub_fs grub_btrfs_fs = {
};
static grub_command_t cmd_info;
+static grub_command_t cmd_mount_subvol;
static grub_extcmd_t cmd_list_subvols;
static char *
@@ -2308,6 +2496,9 @@ GRUB_MOD_INIT (btrfs)
cmd_info = grub_register_command("btrfs-info", grub_cmd_btrfs_info,
"DEVICE",
"Print BtrFS info about DEVICE.");
+ cmd_mount_subvol = grub_register_command("btrfs-mount-subvol", grub_cmd_btrfs_mount_subvol,
+ "DEVICE DIRECTORY SUBVOL",
+ "Set btrfs DEVICE the DIRECTORY a mountpoint of SUBVOL.");
cmd_list_subvols = grub_register_extcmd("btrfs-list-subvols",
grub_cmd_btrfs_list_subvols, 0,
"[-p|-n] [-o var] DEVICE",
