320 lines
6.9 KiB
C
320 lines
6.9 KiB
C
/*
|
|
* Copyright (C) 2011 Novell Inc.
|
|
* Copyright (C) 2016 Red Hat, Inc.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 as published by
|
|
* the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/cred.h>
|
|
#include <linux/xattr.h>
|
|
#include "overlayfs.h"
|
|
#include "ovl_entry.h"
|
|
|
|
int ovl_want_write(struct dentry *dentry)
|
|
{
|
|
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
|
return mnt_want_write(ofs->upper_mnt);
|
|
}
|
|
|
|
void ovl_drop_write(struct dentry *dentry)
|
|
{
|
|
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
|
mnt_drop_write(ofs->upper_mnt);
|
|
}
|
|
|
|
struct dentry *ovl_workdir(struct dentry *dentry)
|
|
{
|
|
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
|
return ofs->workdir;
|
|
}
|
|
|
|
const struct cred *ovl_override_creds(struct super_block *sb)
|
|
{
|
|
struct ovl_fs *ofs = sb->s_fs_info;
|
|
|
|
return override_creds(ofs->creator_cred);
|
|
}
|
|
|
|
struct super_block *ovl_same_sb(struct super_block *sb)
|
|
{
|
|
struct ovl_fs *ofs = sb->s_fs_info;
|
|
|
|
return ofs->same_sb;
|
|
}
|
|
|
|
struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
|
|
{
|
|
size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
|
|
struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
|
|
|
|
if (oe)
|
|
oe->numlower = numlower;
|
|
|
|
return oe;
|
|
}
|
|
|
|
bool ovl_dentry_remote(struct dentry *dentry)
|
|
{
|
|
return dentry->d_flags &
|
|
(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
|
|
DCACHE_OP_REAL);
|
|
}
|
|
|
|
bool ovl_dentry_weird(struct dentry *dentry)
|
|
{
|
|
return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
|
|
DCACHE_MANAGE_TRANSIT |
|
|
DCACHE_OP_HASH |
|
|
DCACHE_OP_COMPARE);
|
|
}
|
|
|
|
enum ovl_path_type ovl_path_type(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
enum ovl_path_type type = 0;
|
|
|
|
if (oe->__upperdentry) {
|
|
type = __OVL_PATH_UPPER;
|
|
|
|
/*
|
|
* Non-dir dentry can hold lower dentry of its copy up origin.
|
|
*/
|
|
if (oe->numlower) {
|
|
type |= __OVL_PATH_ORIGIN;
|
|
if (d_is_dir(dentry))
|
|
type |= __OVL_PATH_MERGE;
|
|
}
|
|
} else {
|
|
if (oe->numlower > 1)
|
|
type |= __OVL_PATH_MERGE;
|
|
}
|
|
return type;
|
|
}
|
|
|
|
void ovl_path_upper(struct dentry *dentry, struct path *path)
|
|
{
|
|
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
path->mnt = ofs->upper_mnt;
|
|
path->dentry = ovl_upperdentry_dereference(oe);
|
|
}
|
|
|
|
void ovl_path_lower(struct dentry *dentry, struct path *path)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
*path = oe->numlower ? oe->lowerstack[0] : (struct path) { };
|
|
}
|
|
|
|
enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
|
|
{
|
|
enum ovl_path_type type = ovl_path_type(dentry);
|
|
|
|
if (!OVL_TYPE_UPPER(type))
|
|
ovl_path_lower(dentry, path);
|
|
else
|
|
ovl_path_upper(dentry, path);
|
|
|
|
return type;
|
|
}
|
|
|
|
struct dentry *ovl_dentry_upper(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
return ovl_upperdentry_dereference(oe);
|
|
}
|
|
|
|
static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
|
|
{
|
|
return oe->numlower ? oe->lowerstack[0].dentry : NULL;
|
|
}
|
|
|
|
struct dentry *ovl_dentry_lower(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
return __ovl_dentry_lower(oe);
|
|
}
|
|
|
|
struct dentry *ovl_dentry_real(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
struct dentry *realdentry;
|
|
|
|
realdentry = ovl_upperdentry_dereference(oe);
|
|
if (!realdentry)
|
|
realdentry = __ovl_dentry_lower(oe);
|
|
|
|
return realdentry;
|
|
}
|
|
|
|
struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
return oe->cache;
|
|
}
|
|
|
|
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
oe->cache = cache;
|
|
}
|
|
|
|
bool ovl_dentry_is_opaque(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
return oe->opaque;
|
|
}
|
|
|
|
bool ovl_dentry_is_whiteout(struct dentry *dentry)
|
|
{
|
|
return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
|
|
}
|
|
|
|
void ovl_dentry_set_opaque(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
oe->opaque = true;
|
|
}
|
|
|
|
bool ovl_redirect_dir(struct super_block *sb)
|
|
{
|
|
struct ovl_fs *ofs = sb->s_fs_info;
|
|
|
|
return ofs->config.redirect_dir && !ofs->noxattr;
|
|
}
|
|
|
|
const char *ovl_dentry_get_redirect(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
return oe->redirect;
|
|
}
|
|
|
|
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
kfree(oe->redirect);
|
|
oe->redirect = redirect;
|
|
}
|
|
|
|
void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
|
|
WARN_ON(oe->__upperdentry);
|
|
/*
|
|
* Make sure upperdentry is consistent before making it visible to
|
|
* ovl_upperdentry_dereference().
|
|
*/
|
|
smp_wmb();
|
|
oe->__upperdentry = upperdentry;
|
|
}
|
|
|
|
void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper)
|
|
{
|
|
WRITE_ONCE(inode->i_private, (unsigned long) realinode |
|
|
(is_upper ? OVL_ISUPPER_MASK : 0));
|
|
}
|
|
|
|
void ovl_inode_update(struct inode *inode, struct inode *upperinode)
|
|
{
|
|
WARN_ON(!upperinode);
|
|
WARN_ON(!inode_unhashed(inode));
|
|
WRITE_ONCE(inode->i_private,
|
|
(unsigned long) upperinode | OVL_ISUPPER_MASK);
|
|
if (!S_ISDIR(upperinode->i_mode))
|
|
__insert_inode_hash(inode, (unsigned long) upperinode);
|
|
}
|
|
|
|
void ovl_dentry_version_inc(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
WARN_ON(!inode_is_locked(dentry->d_inode));
|
|
oe->version++;
|
|
}
|
|
|
|
u64 ovl_dentry_version_get(struct dentry *dentry)
|
|
{
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
WARN_ON(!inode_is_locked(dentry->d_inode));
|
|
return oe->version;
|
|
}
|
|
|
|
bool ovl_is_whiteout(struct dentry *dentry)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
|
|
return inode && IS_WHITEOUT(inode);
|
|
}
|
|
|
|
struct file *ovl_path_open(struct path *path, int flags)
|
|
{
|
|
return dentry_open(path, flags | O_NOATIME, current_cred());
|
|
}
|
|
|
|
int ovl_copy_up_start(struct dentry *dentry)
|
|
{
|
|
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
int err;
|
|
|
|
spin_lock(&ofs->copyup_wq.lock);
|
|
err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);
|
|
if (!err) {
|
|
if (oe->__upperdentry)
|
|
err = 1; /* Already copied up */
|
|
else
|
|
oe->copying = true;
|
|
}
|
|
spin_unlock(&ofs->copyup_wq.lock);
|
|
|
|
return err;
|
|
}
|
|
|
|
void ovl_copy_up_end(struct dentry *dentry)
|
|
{
|
|
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
|
struct ovl_entry *oe = dentry->d_fsdata;
|
|
|
|
spin_lock(&ofs->copyup_wq.lock);
|
|
oe->copying = false;
|
|
wake_up_locked(&ofs->copyup_wq);
|
|
spin_unlock(&ofs->copyup_wq.lock);
|
|
}
|
|
|
|
int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
|
|
const char *name, const void *value, size_t size,
|
|
int xerr)
|
|
{
|
|
int err;
|
|
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
|
|
|
|
if (ofs->noxattr)
|
|
return xerr;
|
|
|
|
err = ovl_do_setxattr(upperdentry, name, value, size, 0);
|
|
|
|
if (err == -EOPNOTSUPP) {
|
|
pr_warn("overlayfs: cannot set %s xattr on upper\n", name);
|
|
ofs->noxattr = true;
|
|
return xerr;
|
|
}
|
|
|
|
return err;
|
|
}
|