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static int copy_fs(unsigned long clone_flags, struct task_struct *tsk){ struct fs_struct *fs = current->fs; if (clone_flags & CLONE_FS) {  /* tsk->fs is already what we want */  spin_lock(&fs->lock);  if (fs->in_exec) {   spin_unlock(&fs->lock);   return -EAGAIN;  }  fs->users++;  spin_unlock(&fs->lock);  return 0; } tsk->fs = copy_fs_struct(fs); if (!tsk->fs)  return -ENOMEM; return 0;}

struct fs_struct *copy_fs_struct(struct fs_struct *old){ struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL); /* We don't need to lock fs - think why ;-) */ if (fs) {  fs->users = 1;  fs->in_exec = 0;  spin_lock_init(&fs->lock);  seqcount_init(&fs->seq);  fs->umask = old->umask;   spin_lock(&old->lock);  fs->root = old->root;  path_get(&fs->root);  fs->pwd = old->pwd;  path_get(&fs->pwd);  spin_unlock(&old->lock); } return fs;}

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