From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Michael Chang Date: Tue, 9 Jul 2019 13:56:16 +0200 Subject: [PATCH] grub2-btrfs-06-subvol-mount --- grub-core/fs/btrfs.c | 195 +++++++++++++++++++++++++++++++++++++++- grub-core/osdep/linux/getroot.c | 148 +++++++++++++++++++++++++++++- util/grub-install.c | 49 ++++++++++ include/grub/emu/getroot.h | 5 ++ 4 files changed, 392 insertions(+), 5 deletions(-) diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c index 113c1f746c9..d323746ecfa 100644 --- a/grub-core/fs/btrfs.c +++ b/grub-core/fs/btrfs.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include #include @@ -266,6 +267,12 @@ 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) @@ -1223,9 +1230,26 @@ lookup_root_by_name(struct grub_btrfs_data *data, const char *path) 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); @@ -2199,11 +2223,20 @@ grub_btrfs_dir (grub_device_t device, const char *path, 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); @@ -2305,11 +2338,21 @@ grub_btrfs_open (struct grub_file *file, const char *name) 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); @@ -2480,6 +2523,150 @@ grub_cmd_btrfs_info (grub_command_t cmd __attribute__ ((unused)), int argc, 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 and "); + + 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, @@ -2686,6 +2873,7 @@ 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 * @@ -2749,6 +2937,9 @@ 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", diff --git a/grub-core/osdep/linux/getroot.c b/grub-core/osdep/linux/getroot.c index caf9b1ccd3f..28790307e00 100644 --- a/grub-core/osdep/linux/getroot.c +++ b/grub-core/osdep/linux/getroot.c @@ -107,6 +107,14 @@ struct btrfs_ioctl_search_key grub_uint32_t unused[9]; }; +struct btrfs_ioctl_search_header { + grub_uint64_t transid; + grub_uint64_t objectid; + grub_uint64_t offset; + grub_uint32_t type; + grub_uint32_t len; +}; + struct btrfs_ioctl_search_args { struct btrfs_ioctl_search_key key; grub_uint64_t buf[(4096 - sizeof(struct btrfs_ioctl_search_key)) @@ -378,6 +386,109 @@ get_btrfs_fs_prefix (const char *mount_path) int use_relative_path_on_btrfs = 0; +static char * +get_btrfs_subvol (const char *path) +{ + struct btrfs_ioctl_ino_lookup_args args; + grub_uint64_t tree_id; + int fd = -1; + char *ret = NULL; + + fd = open (path, O_RDONLY); + + if (fd < 0) + return NULL; + + memset (&args, 0, sizeof(args)); + args.objectid = GRUB_BTRFS_TREE_ROOT_OBJECTID; + + if (ioctl (fd, BTRFS_IOC_INO_LOOKUP, &args) < 0) + goto error; + + tree_id = args.treeid; + + while (tree_id != GRUB_BTRFS_ROOT_VOL_OBJECTID) + { + struct btrfs_ioctl_search_args sargs; + struct grub_btrfs_root_backref *br; + struct btrfs_ioctl_search_header *search_header; + char *old; + grub_uint16_t len; + grub_uint64_t inode_id; + + memset (&sargs, 0, sizeof(sargs)); + + sargs.key.tree_id = 1; + sargs.key.min_objectid = tree_id; + sargs.key.max_objectid = tree_id; + + sargs.key.min_offset = 0; + sargs.key.max_offset = ~0ULL; + sargs.key.min_transid = 0; + sargs.key.max_transid = ~0ULL; + sargs.key.min_type = GRUB_BTRFS_ITEM_TYPE_ROOT_BACKREF; + sargs.key.max_type = GRUB_BTRFS_ITEM_TYPE_ROOT_BACKREF; + + sargs.key.nr_items = 1; + + if (ioctl (fd, BTRFS_IOC_TREE_SEARCH, &sargs) < 0) + goto error; + + if (sargs.key.nr_items == 0) + goto error; + + search_header = (struct btrfs_ioctl_search_header *)sargs.buf; + br = (struct grub_btrfs_root_backref *) (search_header + 1); + + len = grub_le_to_cpu16 (br->n); + inode_id = grub_le_to_cpu64 (br->inode_id); + tree_id = search_header->offset; + + old = ret; + ret = malloc (len + 1); + memcpy (ret, br->name, len); + ret[len] = '\0'; + + if (inode_id != GRUB_BTRFS_TREE_ROOT_OBJECTID) + { + char *s; + + memset(&args, 0, sizeof(args)); + args.treeid = search_header->offset; + args.objectid = inode_id; + + if (ioctl (fd, BTRFS_IOC_INO_LOOKUP, &args) < 0) + goto error; + + s = xasprintf ("%s%s", args.name, ret); + free (ret); + ret = s; + } + + if (old) + { + char *s = xasprintf ("%s/%s", ret, old); + free (ret); + free (old); + ret = s; + } + } + + close (fd); + return ret; + +error: + + if (fd >= 0) + close (fd); + if (ret) + free (ret); + + return NULL; +} + +void (*grub_find_root_btrfs_mount_path_hook)(const char *mount_path); + char ** grub_find_root_devices_from_mountinfo (const char *dir, char **relroot) { @@ -519,12 +630,15 @@ again: else if (grub_strcmp (entries[i].fstype, "btrfs") == 0) { ret = grub_find_root_devices_from_btrfs (dir); - fs_prefix = get_btrfs_fs_prefix (entries[i].enc_path); if (use_relative_path_on_btrfs) { - if (fs_prefix) - free (fs_prefix); fs_prefix = xstrdup ("/"); + if (grub_find_root_btrfs_mount_path_hook) + grub_find_root_btrfs_mount_path_hook (entries[i].enc_path); + } + else + { + fs_prefix = get_btrfs_fs_prefix (entries[i].enc_path); } } else if (!retry && grub_strcmp (entries[i].fstype, "autofs") == 0) @@ -1150,6 +1264,34 @@ grub_util_get_grub_dev_os (const char *os_dev) return grub_dev; } + +char * +grub_util_get_btrfs_subvol (const char *path, char **mount_path) +{ + char *mp = NULL; + + if (mount_path) + *mount_path = NULL; + + auto void + mount_path_hook (const char *m) + { + mp = strdup (m); + } + + grub_find_root_btrfs_mount_path_hook = mount_path_hook; + grub_free (grub_find_root_devices_from_mountinfo (path, NULL)); + grub_find_root_btrfs_mount_path_hook = NULL; + + if (!mp) + return NULL; + + if (mount_path) + *mount_path = mp; + + return get_btrfs_subvol (mp); +} + char * grub_make_system_path_relative_to_its_root_os (const char *path) { diff --git a/util/grub-install.c b/util/grub-install.c index 0f66f36d23a..84ed6e88ecb 100644 --- a/util/grub-install.c +++ b/util/grub-install.c @@ -1569,6 +1569,55 @@ main (int argc, char *argv[]) prefix_drive = xasprintf ("(%s)", grub_drives[0]); } +#ifdef __linux__ + + if (config.is_suse_btrfs_snapshot_enabled + && grub_strncmp(grub_fs->name, "btrfs", sizeof ("btrfs") - 1) == 0) + { + char *subvol = NULL; + char *mount_path = NULL; + char **rootdir_devices = NULL; + char *rootdir_path = grub_util_path_concat (2, "/", rootdir); + + if (grub_util_is_directory (rootdir_path)) + rootdir_devices = grub_guess_root_devices (rootdir_path); + + free (rootdir_path); + + if (rootdir_devices && rootdir_devices[0]) + if (grub_strcmp (rootdir_devices[0], grub_devices[0]) == 0) + subvol = grub_util_get_btrfs_subvol (platdir, &mount_path); + + if (subvol && mount_path) + { + char *def_subvol; + + def_subvol = grub_util_get_btrfs_subvol ("/", NULL); + + if (def_subvol) + { + if (!load_cfg_f) + load_cfg_f = grub_util_fopen (load_cfg, "wb"); + have_load_cfg = 1; + + if (grub_strcmp (subvol, def_subvol) != 0) + fprintf (load_cfg_f, "btrfs-mount-subvol ($root) %s %s\n", mount_path, subvol); + free (def_subvol); + } + } + + for (curdev = rootdir_devices; *curdev; curdev++) + free (*curdev); + if (rootdir_devices) + free (rootdir_devices); + if (subvol) + free (subvol); + if (mount_path) + free (mount_path); + } + +#endif + char mkimage_target[200]; const char *core_name = NULL; diff --git a/include/grub/emu/getroot.h b/include/grub/emu/getroot.h index 73fa2d34abb..9c642ae3fe3 100644 --- a/include/grub/emu/getroot.h +++ b/include/grub/emu/getroot.h @@ -53,6 +53,11 @@ char ** grub_find_root_devices_from_mountinfo (const char *dir, char **relroot); #endif +#ifdef __linux__ +char * +grub_util_get_btrfs_subvol (const char *path, char **mount_path); +#endif + /* Devmapper functions provided by getroot_devmapper.c. */ void grub_util_pull_devmapper (const char *os_dev);