wok annotate linux/stuff/linux-subroot.u @ rev 15844

dosfstools, flac: update WGET_URL
author Pascal Bellard <pascal.bellard@slitaz.org>
date Mon Jan 27 11:21:33 2014 +0000 (2014-01-27)
parents 8580e54b5284
children db5b03f42dd9
rev   line source
pascal@14760 1 Allow to boot on any directories in a filesystem. You will be able to :
pascal@14760 2 - have several distributions in one partition
pascal@14760 3 - use efficently the disk space between several distributions
pascal@14760 4 - deduplicate files across several distributions
pascal@15844 5 - create pseudo snapshots using "cp -al" outside /
pascal@14760 6 - test new configurations
pascal@14760 7 ...
pascal@14761 8 The bad news : you can't remount /
pascal@14761 9
pascal@15671 10 --- linux-3.2.53/Documentation/kernel-parameters.txt
pascal@15671 11 +++ linux-3.2.53/Documentation/kernel-parameters.txt
pascal@15671 12 @@ -2324,8 +2324,9 @@
pascal@14759 13
pascal@14759 14 ro [KNL] Mount root device read-only on boot
pascal@14759 15
pascal@14759 16 - root= [KNL] Root filesystem
pascal@14759 17 + root= [KNL] Root filesystem and root directory
pascal@14759 18 See name_to_dev_t comment in init/do_mounts.c.
pascal@14759 19 + Format: <root_filesystem>[:root_directory]
pascal@14759 20
pascal@14759 21 rootdelay= [KNL] Delay (in seconds) to pause before attempting to
pascal@14759 22 mount the root filesystem
pascal@14759 23 --- linux-3.2.40/init/do_mounts.c
pascal@14759 24 +++ linux-3.2.40/init/do_mounts.c
pascal@14759 25 @@ -28,6 +28,7 @@
pascal@14759 26 int root_mountflags = MS_RDONLY | MS_SILENT;
pascal@14759 27 static char * __initdata root_device_name;
pascal@14759 28 static char __initdata saved_root_name[64];
pascal@14759 29 +static char __initdata saved_root_directory[256];
pascal@14759 30 static int root_wait;
pascal@14759 31
pascal@14759 32 dev_t ROOT_DEV;
pascal@14759 33 @@ -255,7 +256,20 @@
pascal@14759 34
pascal@14759 35 static int __init root_dev_setup(char *line)
pascal@14759 36 {
pascal@14759 37 + char *s;
pascal@14759 38 +
pascal@14759 39 + strcpy(saved_root_directory, ".");
pascal@14759 40 strlcpy(saved_root_name, line, sizeof(saved_root_name));
pascal@14759 41 + s = strchr(saved_root_name, ':');
pascal@14759 42 + if (s) {
pascal@14759 43 + *s = '\0';
pascal@14759 44 + s = strchr(line, ':');
pascal@14759 45 + for (s++; *s == '/'; s++);
pascal@14759 46 + if (*s) {
pascal@14759 47 + strlcpy(saved_root_directory, s,
pascal@14759 48 + sizeof(saved_root_directory));
pascal@14759 49 + }
pascal@14759 50 + }
pascal@14759 51 return 1;
pascal@14759 52 }
pascal@14759 53
pascal@14759 54 @@ -554,5 +568,5 @@
pascal@14759 55 out:
pascal@14759 56 devtmpfs_mount("dev");
pascal@14759 57 sys_mount(".", "/", NULL, MS_MOVE, NULL);
pascal@14759 58 - sys_chroot((const char __user __force *)".");
pascal@14759 59 + sys_chroot((const char __user __force *)saved_root_directory);
pascal@14759 60 }