From 257f871993474e2bde6c497b54022c362cf398e1 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Wed, 4 Nov 2015 10:59:52 -0800 Subject: ovl: move super block magic number to magic.h The overlayfs file system is not recognized by programs like tail because the magic number is not in standard header location. Move it so that the value will propagate on for the GNU library and utilities. Needs to go in the fstatfs manual page as well. Signed-off-by: Stephen Hemminger Signed-off-by: Miklos Szeredi --- include/uapi/linux/magic.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi/linux/magic.h') diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index 7b1425a6b370..eec438952aa7 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -31,6 +31,7 @@ #define PSTOREFS_MAGIC 0x6165676C #define EFIVARFS_MAGIC 0xde5e81e4 #define HOSTFS_SUPER_MAGIC 0x00c0ffee +#define OVERLAYFS_SUPER_MAGIC 0x794c7630 #define MINIX_SUPER_MAGIC 0x137F /* minix v1 fs, 14 char names */ #define MINIX_SUPER_MAGIC2 0x138F /* minix v1 fs, 30 char names */ -- cgit v1.2.3 From 67e9c74b8a873408c27ac9a8e4c1d1c8d72c93ff Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 16 Nov 2015 11:13:34 -0500 Subject: cgroup: replace __DEVEL__sane_behavior with cgroup2 fs type With major controllers - cpu, memory and io - shaping up for the unified hierarchy, cgroup2 is about ready to be, gradually, released into the wild. Replace __DEVEL__sane_behavior flag which was used to select the unified hierarchy with a separate filesystem type "cgroup2" so that unified hierarchy can be mounted as follows. mount -t cgroup2 none $MOUNT_POINT The cgroup2 fs has its own magic number - 0x63677270 ("cgrp"). v2: Assign a different magic number to cgroup2 fs. Signed-off-by: Tejun Heo Acked-by: Li Zefan Cc: Johannes Weiner --- Documentation/cgroups/unified-hierarchy.txt | 6 ++-- include/linux/cgroup-defs.h | 1 - include/uapi/linux/magic.h | 1 + kernel/cgroup.c | 47 ++++++++++++++--------------- 4 files changed, 26 insertions(+), 29 deletions(-) (limited to 'include/uapi/linux/magic.h') diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt index 781b1d475bcf..c1f0e8780960 100644 --- a/Documentation/cgroups/unified-hierarchy.txt +++ b/Documentation/cgroups/unified-hierarchy.txt @@ -94,11 +94,9 @@ the process. 2-1. Mounting -Currently, unified hierarchy can be mounted with the following mount -command. Note that this is still under development and scheduled to -change soon. +Unified hierarchy can be mounted with the following mount command. - mount -t cgroup -o __DEVEL__sane_behavior cgroup $MOUNT_POINT + mount -t cgroup2 none $MOUNT_POINT All controllers which support the unified hierarchy and are not bound to other hierarchies are automatically bound to unified hierarchy and diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 869fd4a3d28e..80e2ae655208 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -66,7 +66,6 @@ enum { /* cgroup_root->flags */ enum { - CGRP_ROOT_SANE_BEHAVIOR = (1 << 0), /* __DEVEL__sane_behavior specified */ CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ }; diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index accb036bbc9c..b283d56c1db9 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -54,6 +54,7 @@ #define SMB_SUPER_MAGIC 0x517B #define CGROUP_SUPER_MAGIC 0x27e0eb +#define CGROUP2_SUPER_MAGIC 0x63677270 #define STACK_END_MAGIC 0x57AC6E9D diff --git a/kernel/cgroup.c b/kernel/cgroup.c index b316debadeb3..af0886262f58 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -211,6 +211,7 @@ static unsigned long have_free_callback __read_mostly; /* Ditto for the can_fork callback. */ static unsigned long have_canfork_callback __read_mostly; +static struct file_system_type cgroup2_fs_type; static struct cftype cgroup_dfl_base_files[]; static struct cftype cgroup_legacy_base_files[]; @@ -1641,10 +1642,6 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) all_ss = true; continue; } - if (!strcmp(token, "__DEVEL__sane_behavior")) { - opts->flags |= CGRP_ROOT_SANE_BEHAVIOR; - continue; - } if (!strcmp(token, "noprefix")) { opts->flags |= CGRP_ROOT_NOPREFIX; continue; @@ -1711,15 +1708,6 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) return -ENOENT; } - if (opts->flags & CGRP_ROOT_SANE_BEHAVIOR) { - pr_warn("sane_behavior: this is still under development and its behaviors will change, proceed at your own risk\n"); - if (nr_opts != 1) { - pr_err("sane_behavior: no other mount options allowed\n"); - return -EINVAL; - } - return 0; - } - /* * If the 'all' option was specified select all the subsystems, * otherwise if 'none', 'name=' and a subsystem name options were @@ -1998,6 +1986,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, int flags, const char *unused_dev_name, void *data) { + bool is_v2 = fs_type == &cgroup2_fs_type; struct super_block *pinned_sb = NULL; struct cgroup_subsys *ss; struct cgroup_root *root; @@ -2014,6 +2003,17 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, if (!use_task_css_set_links) cgroup_enable_task_cg_lists(); + if (is_v2) { + if (data) { + pr_err("cgroup2: unknown option \"%s\"\n", (char *)data); + return ERR_PTR(-EINVAL); + } + cgrp_dfl_root_visible = true; + root = &cgrp_dfl_root; + cgroup_get(&root->cgrp); + goto out_mount; + } + mutex_lock(&cgroup_mutex); /* First find the desired set of subsystems */ @@ -2021,15 +2021,6 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, if (ret) goto out_unlock; - /* look for a matching existing root */ - if (opts.flags & CGRP_ROOT_SANE_BEHAVIOR) { - cgrp_dfl_root_visible = true; - root = &cgrp_dfl_root; - cgroup_get(&root->cgrp); - ret = 0; - goto out_unlock; - } - /* * Destruction of cgroup root is asynchronous, so subsystems may * still be dying after the previous unmount. Let's drain the @@ -2140,9 +2131,10 @@ out_free: if (ret) return ERR_PTR(ret); - +out_mount: dentry = kernfs_mount(fs_type, flags, root->kf_root, - CGROUP_SUPER_MAGIC, &new_sb); + is_v2 ? CGROUP2_SUPER_MAGIC : CGROUP_SUPER_MAGIC, + &new_sb); if (IS_ERR(dentry) || !new_sb) cgroup_put(&root->cgrp); @@ -2185,6 +2177,12 @@ static struct file_system_type cgroup_fs_type = { .kill_sb = cgroup_kill_sb, }; +static struct file_system_type cgroup2_fs_type = { + .name = "cgroup2", + .mount = cgroup_mount, + .kill_sb = cgroup_kill_sb, +}; + /** * task_cgroup_path - cgroup path of a task in the first cgroup hierarchy * @task: target task @@ -5315,6 +5313,7 @@ int __init cgroup_init(void) WARN_ON(sysfs_create_mount_point(fs_kobj, "cgroup")); WARN_ON(register_filesystem(&cgroup_fs_type)); + WARN_ON(register_filesystem(&cgroup2_fs_type)); WARN_ON(!proc_create("cgroups", 0, NULL, &proc_cgroupstats_operations)); return 0; -- cgit v1.2.3