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Commit 71d883c3 authored by Al Viro's avatar Al Viro
Browse files

cgroup_do_mount(): massage calling conventions 



pass it fs_context instead of fs_type/flags/root triple, have
it return int instead of dentry and make it deal with setting
fc->root.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent cf6299b1

kernel/cgroup/cgroup-internal.h

+1 −2
Original line number Diff line number Diff line
@@ -212,8 +212,7 @@ void cgroup_free_root(struct cgroup_root *root); 
void init_cgroup_root(struct cgroup_fs_context *ctx);

int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);

int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);

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

			       struct cgroup_root *root, unsigned long magic,

int cgroup_do_mount(struct fs_context *fc, unsigned long magic,

			       struct cgroup_namespace *ns);



int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);

kernel/cgroup/cgroup-v1.c

+5 −12
Original line number Diff line number Diff line
@@ -1141,7 +1141,6 @@ int cgroup1_get_tree(struct fs_context *fc) 
	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);

	struct cgroup_root *root;

	struct cgroup_subsys *ss;

	struct dentry *dentry;

	int i, ret;



	/* Check if the caller has permission to mount. */
@@ -1253,21 +1252,15 @@ int cgroup1_get_tree(struct fs_context *fc) 
	if (ret)

		return ret;



	dentry = cgroup_do_mount(&cgroup_fs_type, fc->sb_flags, root,

				 CGROUP_SUPER_MAGIC, ns);

	if (IS_ERR(dentry))

		return PTR_ERR(dentry);



	if (percpu_ref_is_dying(&root->cgrp.self.refcnt)) {

		struct super_block *sb = dentry->d_sb;

		dput(dentry);

	ret = cgroup_do_mount(fc, CGROUP_SUPER_MAGIC, ns);

	if (!ret && percpu_ref_is_dying(&root->cgrp.self.refcnt)) {

		struct super_block *sb = fc->root->d_sb;

		dput(fc->root);

		deactivate_locked_super(sb);

		msleep(10);

		return restart_syscall();

	}



	fc->root = dentry;

	return 0;

	return ret;

}



static int __init cgroup1_wq_init(void)

kernel/cgroup/cgroup.c

+23 −22
Original line number Diff line number Diff line
@@ -2036,43 +2036,48 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) 
	return ret;

}



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

			       struct cgroup_root *root, unsigned long magic,

int cgroup_do_mount(struct fs_context *fc, unsigned long magic,

		    struct cgroup_namespace *ns)

{

	struct dentry *dentry;

	struct cgroup_fs_context *ctx = cgroup_fc2context(fc);

	bool new_sb = false;

	int ret = 0;



	dentry = kernfs_mount(fs_type, flags, root->kf_root, magic, &new_sb);

	fc->root = kernfs_mount(fc->fs_type, fc->sb_flags, ctx->root->kf_root,

				magic, &new_sb);

	if (IS_ERR(fc->root))

		ret = PTR_ERR(fc->root);



	/*

	 * In non-init cgroup namespace, instead of root cgroup's dentry,

	 * we return the dentry corresponding to the cgroupns->root_cgrp.

	 */

	if (!IS_ERR(dentry) && ns != &init_cgroup_ns) {

	if (!ret && ns != &init_cgroup_ns) {

		struct dentry *nsdentry;

		struct super_block *sb = dentry->d_sb;

		struct super_block *sb = fc->root->d_sb;

		struct cgroup *cgrp;



		mutex_lock(&cgroup_mutex);

		spin_lock_irq(&css_set_lock);



		cgrp = cset_cgroup_from_root(ns->root_cset, root);

		cgrp = cset_cgroup_from_root(ns->root_cset, ctx->root);



		spin_unlock_irq(&css_set_lock);

		mutex_unlock(&cgroup_mutex);



		nsdentry = kernfs_node_dentry(cgrp->kn, sb);

		dput(dentry);

		if (IS_ERR(nsdentry))

		dput(fc->root);

		fc->root = nsdentry;

		if (IS_ERR(nsdentry)) {

			ret = PTR_ERR(nsdentry);

			deactivate_locked_super(sb);

		dentry = nsdentry;

		}

	}



	if (!new_sb)

		cgroup_put(&root->cgrp);

		cgroup_put(&ctx->root->cgrp);



	return dentry;

	return ret;

}



/*
@@ -2091,7 +2096,7 @@ 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);

	struct dentry *root;

	int ret;



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

	if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
@@ -2101,14 +2106,10 @@ static int cgroup_get_tree(struct fs_context *fc) 
	cgroup_get_live(&cgrp_dfl_root.cgrp);

	ctx->root = &cgrp_dfl_root;



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

					 CGROUP2_SUPER_MAGIC, ns);

	if (IS_ERR(root))

		return PTR_ERR(root);



	ret = cgroup_do_mount(fc, CGROUP2_SUPER_MAGIC, ns);

	if (!ret)

		apply_cgroup_root_flags(ctx->flags);

	fc->root = root;

	return 0;

	return ret;

}



static const struct fs_context_operations cgroup_fs_context_ops = {