Commit 90129625 authored by Al Viro's avatar Al Viro
Browse files

cgroup: start switching to fs_context 



Unfortunately, cgroup is tangled into kernfs infrastructure.
To avoid converting all kernfs-based filesystems at once,
we need to untangle the remount part of things, instead of
having it go through kernfs_sop_remount_fs().  Fortunately,
it's not hard to do.

This commit just gets cgroup/cgroup1 to use fs_context to
deliver options on mount and remount paths.  Parsing those
is going to be done in the next commits; for now we do
pretty much what legacy case does.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 935c6912

kernel/cgroup/cgroup-internal.h

+14 −0
Original line number Original line Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/workqueue.h>

#include <linux/workqueue.h>

#include <linux/list.h>

#include <linux/list.h>

#include <linux/refcount.h>

#include <linux/refcount.h>

#include <linux/fs_context.h>





#define TRACE_CGROUP_PATH_LEN 1024

#define TRACE_CGROUP_PATH_LEN 1024

extern spinlock_t trace_cgroup_path_lock;

extern spinlock_t trace_cgroup_path_lock;
@@ -36,6 +37,18 @@ extern void __init enable_debug_cgroup(void); 
		}							\

		}							\

	} while (0)

	} while (0)





/*

 * The cgroup filesystem superblock creation/mount context.

 */

struct cgroup_fs_context {

	char *data;

};



static inline struct cgroup_fs_context *cgroup_fc2context(struct fs_context *fc)

{

	return fc->fs_private;

}



/*

/*

 * A cgroup can be associated with multiple css_sets as different tasks may

 * A cgroup can be associated with multiple css_sets as different tasks may

 * belong to different cgroups on different hierarchies.  In the other

 * belong to different cgroups on different hierarchies.  In the other
@@ -255,5 +268,6 @@ void cgroup1_check_for_release(struct cgroup *cgrp); 
struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,

struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,

			     void *data, unsigned long magic,

			     void *data, unsigned long magic,

			     struct cgroup_namespace *ns);

			     struct cgroup_namespace *ns);

int cgroup1_reconfigure(struct fs_context *ctx);





#endif /* __CGROUP_INTERNAL_H */
 
#endif /* __CGROUP_INTERNAL_H */

kernel/cgroup/cgroup-v1.c

+5 −4
Original line number Original line Diff line number Diff line
@@ -1046,17 +1046,19 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) 
	return 0;

	return 0;

}

}





static int cgroup1_remount(struct kernfs_root *kf_root, int *flags, char *data)

int cgroup1_reconfigure(struct fs_context *fc)

{

{

	int ret = 0;

	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);

	struct kernfs_root *kf_root = kernfs_root_from_sb(fc->root->d_sb);

	struct cgroup_root *root = cgroup_root_from_kf(kf_root);

	struct cgroup_root *root = cgroup_root_from_kf(kf_root);

	int ret = 0;

	struct cgroup_sb_opts opts;

	struct cgroup_sb_opts opts;

	u16 added_mask, removed_mask;

	u16 added_mask, removed_mask;





	cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);

	cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);





	/* See what subsystems are wanted */

	/* See what subsystems are wanted */

	ret = parse_cgroupfs_options(data, &opts);

	ret = parse_cgroupfs_options(ctx->data, &opts);

	if (ret)

	if (ret)

		goto out_unlock;

		goto out_unlock;
@@ -1106,7 +1108,6 @@ static int cgroup1_remount(struct kernfs_root *kf_root, int *flags, char *data) 
struct kernfs_syscall_ops cgroup1_kf_syscall_ops = {

struct kernfs_syscall_ops cgroup1_kf_syscall_ops = {

	.rename			= cgroup1_rename,

	.rename			= cgroup1_rename,

	.show_options		= cgroup1_show_options,

	.show_options		= cgroup1_show_options,

	.remount_fs		= cgroup1_remount,

	.mkdir			= cgroup_mkdir,

	.mkdir			= cgroup_mkdir,

	.rmdir			= cgroup_rmdir,

	.rmdir			= cgroup_rmdir,

	.show_path		= cgroup_show_path,

	.show_path		= cgroup_show_path,

kernel/cgroup/cgroup.c

+97 −37
Original line number Original line Diff line number Diff line
@@ -1811,12 +1811,13 @@ static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root 
	return 0;

	return 0;

}

}





static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data)

static int cgroup_reconfigure(struct fs_context *fc)

{

{

	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);

	unsigned int root_flags;

	unsigned int root_flags;

	int ret;

	int ret;





	ret = parse_cgroup_root_flags(data, &root_flags);

	ret = parse_cgroup_root_flags(ctx->data, &root_flags);

	if (ret)

	if (ret)

		return ret;

		return ret;
@@ -2067,52 +2068,112 @@ struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags, 
	return dentry;

	return dentry;

}

}





static struct dentry *cgroup_mount(struct file_system_type *fs_type,

/*

			 int flags, const char *unused_dev_name,

 * Destroy a cgroup filesystem context.

			 void *data)

 */

static void cgroup_fs_context_free(struct fs_context *fc)

{

{

	struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;

	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);

	struct dentry *dentry;

	int ret;



	get_cgroup_ns(ns);





	/* Check if the caller has permission to mount. */

	kfree(ctx);

	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) {

		put_cgroup_ns(ns);

		return ERR_PTR(-EPERM);

}

}





	/*

static int cgroup_parse_monolithic(struct fs_context *fc, void *data)

	 * The first time anyone tries to mount a cgroup, enable the list

{

	 * linking each css_set to its tasks and fix up all existing tasks.

	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);

	 */

	if (!use_task_css_set_links)

		cgroup_enable_task_cg_lists();





	if (fs_type == &cgroup2_fs_type) {

	ctx->data = data;

	if (ctx->data)

		security_sb_eat_lsm_opts(ctx->data, &fc->security);

	return 0;

}



static int cgroup_get_tree(struct fs_context *fc)

{

	struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;

	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);

	unsigned int root_flags;

	unsigned int root_flags;

	struct dentry *root;

	int ret;





		ret = parse_cgroup_root_flags(data, &root_flags);

	/* Check if the caller has permission to mount. */

		if (ret) {

	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))

			put_cgroup_ns(ns);

		return -EPERM;

			return ERR_PTR(ret);



		}

	ret = parse_cgroup_root_flags(ctx->data, &root_flags);

	if (ret)

		return ret;





	cgrp_dfl_visible = true;

	cgrp_dfl_visible = true;

	cgroup_get_live(&cgrp_dfl_root.cgrp);

	cgroup_get_live(&cgrp_dfl_root.cgrp);





		dentry = cgroup_do_mount(&cgroup2_fs_type, flags, &cgrp_dfl_root,

	root = cgroup_do_mount(&cgroup2_fs_type, fc->sb_flags, &cgrp_dfl_root,

					 CGROUP2_SUPER_MAGIC, ns);

					 CGROUP2_SUPER_MAGIC, ns);

		if (!IS_ERR(dentry))

	if (IS_ERR(root))

		return PTR_ERR(root);



	apply_cgroup_root_flags(root_flags);

	apply_cgroup_root_flags(root_flags);

	} else {

	fc->root = root;

		dentry = cgroup1_mount(&cgroup_fs_type, flags, data,

	return 0;

}



static int cgroup1_get_tree(struct fs_context *fc)

{

	struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;

	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);

	struct dentry *root;



	/* Check if the caller has permission to mount. */

	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))

		return -EPERM;



	root = cgroup1_mount(&cgroup_fs_type, fc->sb_flags, ctx->data,

				       CGROUP_SUPER_MAGIC, ns);

				       CGROUP_SUPER_MAGIC, ns);

	if (IS_ERR(root))

		return PTR_ERR(root);



	fc->root = root;

	return 0;

}

}





	put_cgroup_ns(ns);

static const struct fs_context_operations cgroup_fs_context_ops = {

	return dentry;

	.free		= cgroup_fs_context_free,

	.parse_monolithic = cgroup_parse_monolithic,

	.get_tree	= cgroup_get_tree,

	.reconfigure	= cgroup_reconfigure,

};



static const struct fs_context_operations cgroup1_fs_context_ops = {

	.free		= cgroup_fs_context_free,

	.parse_monolithic = cgroup_parse_monolithic,

	.get_tree	= cgroup1_get_tree,

	.reconfigure	= cgroup1_reconfigure,

};



/*

 * Initialise the cgroup filesystem creation/reconfiguration context.

 */

static int cgroup_init_fs_context(struct fs_context *fc)

{

	struct cgroup_fs_context *ctx;



	ctx = kzalloc(sizeof(struct cgroup_fs_context), GFP_KERNEL);

	if (!ctx)

		return -ENOMEM;



	/*

	 * The first time anyone tries to mount a cgroup, enable the list

	 * linking each css_set to its tasks and fix up all existing tasks.

	 */

	if (!use_task_css_set_links)

		cgroup_enable_task_cg_lists();



	fc->fs_private = ctx;

	if (fc->fs_type == &cgroup2_fs_type)

		fc->ops = &cgroup_fs_context_ops;

	else

		fc->ops = &cgroup1_fs_context_ops;

	return 0;

}

}





static void cgroup_kill_sb(struct super_block *sb)

static void cgroup_kill_sb(struct super_block *sb)
@@ -2136,14 +2197,14 @@ static void cgroup_kill_sb(struct super_block *sb) 




struct file_system_type cgroup_fs_type = {

struct file_system_type cgroup_fs_type = {

	.name = "cgroup",

	.name = "cgroup",

	.mount = cgroup_mount,

	.init_fs_context = cgroup_init_fs_context,

	.kill_sb = cgroup_kill_sb,

	.kill_sb = cgroup_kill_sb,

	.fs_flags = FS_USERNS_MOUNT,

	.fs_flags = FS_USERNS_MOUNT,

};

};





static struct file_system_type cgroup2_fs_type = {

static struct file_system_type cgroup2_fs_type = {

	.name = "cgroup2",

	.name = "cgroup2",

	.mount = cgroup_mount,

	.init_fs_context = cgroup_init_fs_context,

	.kill_sb = cgroup_kill_sb,

	.kill_sb = cgroup_kill_sb,

	.fs_flags = FS_USERNS_MOUNT,

	.fs_flags = FS_USERNS_MOUNT,

};

};
@@ -5268,7 +5329,6 @@ int cgroup_rmdir(struct kernfs_node *kn) 




static struct kernfs_syscall_ops cgroup_kf_syscall_ops = {

static struct kernfs_syscall_ops cgroup_kf_syscall_ops = {

	.show_options		= cgroup_show_options,

	.show_options		= cgroup_show_options,

	.remount_fs		= cgroup_remount,

	.mkdir			= cgroup_mkdir,

	.mkdir			= cgroup_mkdir,

	.rmdir			= cgroup_rmdir,

	.rmdir			= cgroup_rmdir,

	.show_path		= cgroup_show_path,

	.show_path		= cgroup_show_path,

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