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Make / in btrfs refer to real root, not the default volume.

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Modify mkrelpath to work even if device is mounted with subvolid option.
This commit is contained in:
Vladimir Serbinenko 2013-10-28 01:37:19 +01:00
parent 11d81fc6d1
commit 82591fa6e7
6 changed files with 311 additions and 123 deletions
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194
grub-core/osdep/linux/getroot.c
View file

@ -49,15 +49,18 @@
#include <sys/wait.h>
#include <btrfs/ioctl.h>
#include <linux/types.h>
#include <linux/major.h>
#include <linux/raid/md_p.h>
#include <linux/raid/md_u.h>
#include <grub/i18n.h>
#include <grub/emu/exec.h>
#include <grub/btrfs.h>
#define LVM_DEV_MAPPER_STRING "/dev/mapper/"
#if 0
/* Defines taken from btrfs/ioctl.h. */
struct btrfs_ioctl_dev_info_args
@ -82,7 +85,7 @@ struct btrfs_ioctl_fs_info_args
struct btrfs_ioctl_dev_info_args)
#define BTRFS_IOC_FS_INFO _IOR(0x94, 31, \
struct btrfs_ioctl_fs_info_args)
#endif
static int
grub_util_is_imsm (const char *os_dev);
@ -224,6 +227,117 @@ grub_find_root_devices_from_btrfs (const char *dir)
return ret;
}
static char *
get_btrfs_fs_prefix (const char *mount_path)
{
struct btrfs_ioctl_ino_lookup_args args;
struct stat st;
int fd;
grub_uint64_t tree_id, inode_id;
char *ret = NULL;
fd = open (mount_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)
return NULL;
tree_id = args.treeid;
if (fstat (fd, &st) < 0)
return NULL;
inode_id = st.st_ino;
while (tree_id != GRUB_BTRFS_ROOT_VOL_OBJECTID
|| inode_id != GRUB_BTRFS_TREE_ROOT_OBJECTID)
{
grub_uint64_t *nid;
const char *name;
size_t namelen;
struct btrfs_ioctl_search_args sargs;
char *old;
memset (&sargs, 0, sizeof(sargs));
if (inode_id == GRUB_BTRFS_TREE_ROOT_OBJECTID)
{
struct grub_btrfs_root_backref *br;
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)
return NULL;
if (sargs.key.nr_items == 0)
return NULL;
nid = (grub_uint64_t *) (sargs.buf + 16);
tree_id = *nid;
br = (struct grub_btrfs_root_backref *) (sargs.buf + 32);
inode_id = br->inode_id;
name = br->name;
namelen = br->n;
}
else
{
struct grub_btrfs_inode_ref *ir;
sargs.key.tree_id = tree_id;
sargs.key.min_objectid = inode_id;
sargs.key.max_objectid = inode_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_INODE_REF;
sargs.key.max_type = GRUB_BTRFS_ITEM_TYPE_INODE_REF;
if (ioctl (fd, BTRFS_IOC_TREE_SEARCH, &sargs) < 0)
return NULL;
if (sargs.key.nr_items == 0)
return NULL;
nid = (grub_uint64_t *) (sargs.buf + 16);
inode_id = *nid;
ir = (struct grub_btrfs_inode_ref *) (sargs.buf + 32);
name = ir->name;
namelen = ir->n;
}
old = ret;
ret = xmalloc (namelen + (old ? strlen (old) : 0) + 2);
ret[0] = '/';
memcpy (ret + 1, name, namelen);
if (old)
{
strcpy (ret + 1 + namelen, old);
free (old);
}
else
ret[1+namelen] = '\0';
}
if (!ret)
return xstrdup ("/");
return ret;
}
char **
grub_find_root_devices_from_mountinfo (const char *dir, char **relroot)
{
@ -332,6 +446,7 @@ grub_find_root_devices_from_mountinfo (const char *dir, char **relroot)
for (i = entry_len - 1; i >= 0; i--)
{
char **ret = NULL;
char *fs_prefix = NULL;
if (!*entries[i].device)
continue;
@ -348,45 +463,52 @@ grub_find_root_devices_from_mountinfo (const char *dir, char **relroot)
if (relroot)
{
if (!slash)
*relroot = xasprintf ("/@%s", entries[i].enc_root);
fs_prefix = xasprintf ("/@%s", entries[i].enc_root);
else if (strchr (slash + 1, '@'))
*relroot = xasprintf ("/%s%s", slash + 1, entries[i].enc_root);
fs_prefix = xasprintf ("/%s%s", slash + 1, entries[i].enc_root);
else
*relroot = xasprintf ("/%s@%s", slash + 1, entries[i].enc_root);
fs_prefix = xasprintf ("/%s@%s", slash + 1,
entries[i].enc_root);
}
}
else if (grub_strcmp (entries[i].fstype, "btrfs") == 0)
{
ret = grub_find_root_devices_from_btrfs (dir);
if (relroot)
{
char *ptr;
*relroot = xmalloc (strlen (entries[i].enc_root) +
2 + strlen (dir));
ptr = grub_stpcpy (*relroot, entries[i].enc_root);
if (strlen (dir) > strlen (entries[i].enc_path))
{
while (ptr > *relroot && *(ptr - 1) == '/')
ptr--;
if (dir[strlen (entries[i].enc_path)] != '/')
*ptr++ = '/';
ptr = grub_stpcpy (ptr, dir + strlen (entries[i].enc_path));
}
*ptr = 0;
}
fs_prefix = get_btrfs_fs_prefix (entries[i].enc_path);
}
if (!ret)
{
ret = xmalloc (2 * sizeof (ret[0]));
ret[0] = strdup (entries[i].device);
ret[1] = 0;
if (relroot)
*relroot = strdup (entries[i].enc_root);
}
free (buf);
free (entries);
fclose (fp);
return ret;
if (!fs_prefix)
fs_prefix = entries[i].enc_root;
if (relroot)
{
char *ptr;
grub_size_t enc_root_len = strlen (fs_prefix);
grub_size_t enc_path_len = strlen (entries[i].enc_path);
grub_size_t dir_strlen = strlen (dir);
*relroot = xmalloc (enc_root_len +
2 + dir_strlen);
ptr = grub_stpcpy (*relroot, fs_prefix);
if (dir_strlen > enc_path_len)
{
while (ptr > *relroot && *(ptr - 1) == '/')
ptr--;
if (dir[enc_path_len] != '/')
*ptr++ = '/';
ptr = grub_stpcpy (ptr, dir + enc_path_len);
}
*ptr = 0;
}
if (fs_prefix != entries[i].enc_root)
free (fs_prefix);
free (buf);
free (entries);
fclose (fp);
return ret;
}
free (buf);
@ -913,3 +1035,23 @@ grub_util_get_grub_dev_os (const char *os_dev)
return grub_dev;
}
char *
grub_make_system_path_relative_to_its_root_os (const char *path)
{
char *bind = NULL;
grub_size_t len;
grub_free (grub_find_root_devices_from_mountinfo (path, &bind));
if (bind && bind[0])
{
len = strlen (bind);
while (len > 0 && bind[len - 1] == '/')
{
bind[len - 1] = '\0';
len--;
}
return bind;
}
grub_free (bind);
return NULL;
}