1 #include <linux/export.h>
2 #include <linux/sched.h>
4 #include <linux/path.h>
5 #include <linux/slab.h>
6 #include <linux/fs_struct.h>
10 * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
13 void set_fs_root(struct fs_struct *fs, const struct path *path)
19 write_seqcount_begin(&fs->seq);
22 write_seqcount_end(&fs->seq);
23 spin_unlock(&fs->lock);
29 * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
32 void set_fs_pwd(struct fs_struct *fs, const struct path *path)
38 write_seqcount_begin(&fs->seq);
41 write_seqcount_end(&fs->seq);
42 spin_unlock(&fs->lock);
47 EXPORT_SYMBOL(set_fs_pwd);
49 static inline int replace_path(struct path *p, const struct path *old, const struct path *new)
51 if (likely(p->dentry != old->dentry || p->mnt != old->mnt))
57 void chroot_fs_refs(const struct path *old_root, const struct path *new_root)
59 struct task_struct *g, *p;
63 read_lock(&tasklist_lock);
64 do_each_thread(g, p) {
70 write_seqcount_begin(&fs->seq);
71 hits += replace_path(&fs->root, old_root, new_root);
72 hits += replace_path(&fs->pwd, old_root, new_root);
73 write_seqcount_end(&fs->seq);
78 spin_unlock(&fs->lock);
81 } while_each_thread(g, p);
82 read_unlock(&tasklist_lock);
87 void free_fs_struct(struct fs_struct *fs)
91 kmem_cache_free(fs_cachep, fs);
93 EXPORT_SYMBOL(free_fs_struct);
95 void exit_fs(struct task_struct *tsk)
97 struct fs_struct *fs = tsk->fs;
102 spin_lock(&fs->lock);
105 spin_unlock(&fs->lock);
112 struct fs_struct *copy_fs_struct(struct fs_struct *old)
114 struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
115 /* We don't need to lock fs - think why ;-) */
119 spin_lock_init(&fs->lock);
120 seqcount_init(&fs->seq);
121 fs->umask = old->umask;
123 spin_lock(&old->lock);
124 fs->root = old->root;
128 spin_unlock(&old->lock);
132 EXPORT_SYMBOL_GPL(copy_fs_struct);
134 int unshare_fs_struct(void)
136 struct fs_struct *fs = current->fs;
137 struct fs_struct *new_fs = copy_fs_struct(fs);
144 spin_lock(&fs->lock);
146 current->fs = new_fs;
147 spin_unlock(&fs->lock);
148 task_unlock(current);
155 EXPORT_SYMBOL_GPL(unshare_fs_struct);
157 int current_umask(void)
159 return current->fs->umask;
161 EXPORT_SYMBOL(current_umask);
163 /* to be mentioned only in INIT_TASK */
164 struct fs_struct init_fs = {
166 .lock = __SPIN_LOCK_UNLOCKED(init_fs.lock),
167 .seq = SEQCNT_ZERO(init_fs.seq),