X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fcgroup.c;h=f221446aa02da4d60b32bbc7a8a53354e155c11d;hb=11a7d0e3140d2f3e8052a856e8582ce9b021972c;hp=35eebd5510c2165c6f8daa2cef1fecab9187d6d0;hpb=2077776641b6ffb0049f13018d2e162340ec51c7;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 35eebd5..f221446 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -116,7 +116,6 @@ static int root_count; * be called. */ static int need_forkexit_callback __read_mostly; -static int need_mm_owner_callback __read_mostly; /* convenient tests for these bits */ inline int cgroup_is_removed(const struct cgroup *cgrp) @@ -571,9 +570,8 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb) if (inode) { inode->i_mode = mode; - inode->i_uid = current->fsuid; - inode->i_gid = current->fsgid; - inode->i_blocks = 0; + inode->i_uid = current_fsuid(); + inode->i_gid = current_fsgid(); inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_mapping->backing_dev_info = &cgroup_backing_dev_info; } @@ -702,7 +700,7 @@ static int rebind_subsystems(struct cgroupfs_root *root, * any child cgroups exist. This is theoretically supportable * but involves complex error handling, so it's being left until * later */ - if (!list_empty(&cgrp->children)) + if (root->number_of_cgroups > 1) return -EBUSY; /* Process each subsystem */ @@ -1024,7 +1022,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type, if (ret == -EBUSY) { mutex_unlock(&cgroup_mutex); mutex_unlock(&inode->i_mutex); - goto drop_new_super; + goto free_cg_links; } /* EBUSY should be the only error here */ @@ -1073,10 +1071,11 @@ static int cgroup_get_sb(struct file_system_type *fs_type, return simple_set_mnt(mnt, sb); + free_cg_links: + free_cg_links(&tmp_cg_links); drop_new_super: up_write(&sb->s_umount); deactivate_super(sb); - free_cg_links(&tmp_cg_links); return ret; } @@ -1279,6 +1278,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) static int attach_task_by_pid(struct cgroup *cgrp, u64 pid) { struct task_struct *tsk; + const struct cred *cred = current_cred(), *tcred; int ret; if (pid) { @@ -1288,14 +1288,16 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64 pid) rcu_read_unlock(); return -ESRCH; } - get_task_struct(tsk); - rcu_read_unlock(); - if ((current->euid) && (current->euid != tsk->uid) - && (current->euid != tsk->suid)) { - put_task_struct(tsk); + tcred = __task_cred(tsk); + if (cred->euid && + cred->euid != tcred->uid && + cred->euid != tcred->suid) { + rcu_read_unlock(); return -EACCES; } + get_task_struct(tsk); + rcu_read_unlock(); } else { tsk = current; get_task_struct(tsk); @@ -2039,10 +2041,13 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) struct cgroup *cgrp; struct cgroup_iter it; struct task_struct *tsk; + /* - * Validate dentry by checking the superblock operations + * Validate dentry by checking the superblock operations, + * and make sure it's a directory. */ - if (dentry->d_sb->s_op != &cgroup_ops) + if (dentry->d_sb->s_op != &cgroup_ops || + !S_ISDIR(dentry->d_inode->i_mode)) goto err; ret = 0; @@ -2472,10 +2477,7 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) mutex_unlock(&cgroup_mutex); return -EBUSY; } - - parent = cgrp->parent; - root = cgrp->root; - sb = root->sb; + mutex_unlock(&cgroup_mutex); /* * Call pre_destroy handlers of subsys. Notify subsystems @@ -2483,7 +2485,14 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) */ cgroup_call_pre_destroy(cgrp); - if (cgroup_has_css_refs(cgrp)) { + mutex_lock(&cgroup_mutex); + parent = cgrp->parent; + root = cgrp->root; + sb = root->sb; + + if (atomic_read(&cgrp->count) + || !list_empty(&cgrp->children) + || cgroup_has_css_refs(cgrp)) { mutex_unlock(&cgroup_mutex); return -EBUSY; } @@ -2497,7 +2506,6 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) list_del(&cgrp->sibling); spin_lock(&cgrp->dentry->d_lock); d = dget(cgrp->dentry); - cgrp->dentry = NULL; spin_unlock(&d->d_lock); cgroup_d_remove_dir(d); @@ -2530,7 +2538,6 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) init_css_set.subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id]; need_forkexit_callback |= ss->fork || ss->exit; - need_mm_owner_callback |= !!ss->mm_owner_changed; /* At system boot, before all subsystems have been * registered, no tasks have been forked, so we don't @@ -2780,37 +2787,6 @@ void cgroup_fork_callbacks(struct task_struct *child) } } -#ifdef CONFIG_MM_OWNER -/** - * cgroup_mm_owner_callbacks - run callbacks when the mm->owner changes - * @p: the new owner - * - * Called on every change to mm->owner. mm_init_owner() does not - * invoke this routine, since it assigns the mm->owner the first time - * and does not change it. - * - * The callbacks are invoked with mmap_sem held in read mode. - */ -void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new) -{ - struct cgroup *oldcgrp, *newcgrp = NULL; - - if (need_mm_owner_callback) { - int i; - for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { - struct cgroup_subsys *ss = subsys[i]; - oldcgrp = task_cgroup(old, ss->subsys_id); - if (new) - newcgrp = task_cgroup(new, ss->subsys_id); - if (oldcgrp == newcgrp) - continue; - if (ss->mm_owner_changed) - ss->mm_owner_changed(ss, oldcgrp, newcgrp, new); - } - } -} -#endif /* CONFIG_MM_OWNER */ - /** * cgroup_post_fork - called on a new task after adding it to the task list * @child: the task in question @@ -2928,9 +2904,6 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys, again: root = subsys->root; if (root == &rootnode) { - printk(KERN_INFO - "Not cloning cgroup for unused subsystem %s\n", - subsys->name); mutex_unlock(&cgroup_mutex); return 0; } @@ -2938,7 +2911,11 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys, parent = task_cgroup(tsk, subsys->subsys_id); /* Pin the hierarchy */ - atomic_inc(&parent->root->sb->s_active); + if (!atomic_inc_not_zero(&parent->root->sb->s_active)) { + /* We race with the final deactivate_super() */ + mutex_unlock(&cgroup_mutex); + return 0; + } /* Keep the cgroup alive */ get_css_set(cg);