ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
{
ssize_t res;
int off;
res = vfs_listxattr(ovl_dentry_real(dentry), list, size);
if (res <= 0 || size == 0)
return res;
if (ovl_path_type(dentry->d_parent) != OVL_PATH_MERGE)
return res;
/* filter out private xattrs */
for (off = 0; off < res;) {
char *s = list + off;
size_t slen = strlen(s) + 1;
BUG_ON(off + slen > res);
if (ovl_is_private_xattr(s)) {
res -= slen;
memmove(s, s + slen, res - off);
} else {
off += slen;
}
}
return res;
}
static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd)
{
void *ret;
struct dentry *realdentry;
struct inode *realinode;
realdentry = ovl_dentry_real(dentry);
realinode = realdentry->d_inode;
if (WARN_ON(!realinode->i_op->follow_link))
return ERR_PTR(-EPERM);
ret = realinode->i_op->follow_link(realdentry, nd);
if (IS_ERR(ret))
return ret;
if (realinode->i_op->put_link) {
struct ovl_link_data *data;
data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL);
if (!data) {
realinode->i_op->put_link(realdentry, nd, ret);
return ERR_PTR(-ENOMEM);
}
data->realdentry = realdentry;
data->cookie = ret;
return data;
} else {
return NULL;
}
}
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
{
struct dentry *realdentry = ovl_dentry_real(dentry);
ssize_t res;
size_t len;
char *s;
const struct cred *old_cred;
old_cred = ovl_override_creds(dentry->d_sb);
res = vfs_listxattr(realdentry, list, size);
revert_creds(old_cred);
if (res <= 0 || size == 0)
return res;
/* filter out private xattrs */
for (s = list, len = res; len;) {
size_t slen = strnlen(s, len) + 1;
/* underlying fs providing us with an broken xattr list? */
if (WARN_ON(slen > len))
return -EIO;
len -= slen;
if (!ovl_can_list(s)) {
res -= slen;
memmove(s, s + slen, len);
} else {
s += slen;
}
}
return res;
}
static const char *ovl_follow_link(struct dentry *dentry, void **cookie)
{
struct dentry *realdentry;
struct inode *realinode;
struct ovl_link_data *data = NULL;
const char *ret;
realdentry = ovl_dentry_real(dentry);
realinode = realdentry->d_inode;
if (WARN_ON(!realinode->i_op->follow_link))
return ERR_PTR(-EPERM);
if (realinode->i_op->put_link) {
data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL);
if (!data)
return ERR_PTR(-ENOMEM);
data->realdentry = realdentry;
}
ret = realinode->i_op->follow_link(realdentry, cookie);
if (IS_ERR_OR_NULL(ret)) {
kfree(data);
return ret;
}
if (data)
data->cookie = *cookie;
*cookie = data;
return ret;
}
ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
void *value, size_t size)
{
if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
ovl_is_private_xattr(name))
return -ENODATA;
return vfs_getxattr(ovl_dentry_real(dentry), name, value, size);
}
int ovl_setattr(struct dentry *dentry, struct iattr *attr)
{
int err;
struct dentry *upperdentry;
/*
* Check for permissions before trying to copy-up. This is redundant
* since it will be rechecked later by ->setattr() on upper dentry. But
* without this, copy-up can be triggered by just about anybody.
*
* We don't initialize inode->size, which just means that
* inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not
* check for a swapfile (which this won't be anyway).
*/
err = inode_change_ok(dentry->d_inode, attr);
if (err)
return err;
err = ovl_want_write(dentry);
if (err)
goto out;
if (attr->ia_valid & ATTR_SIZE) {
struct inode *realinode = d_inode(ovl_dentry_real(dentry));
err = -ETXTBSY;
if (atomic_read(&realinode->i_writecount) < 0)
goto out_drop_write;
}
err = ovl_copy_up(dentry);
if (!err) {
struct inode *winode = NULL;
upperdentry = ovl_dentry_upper(dentry);
if (attr->ia_valid & ATTR_SIZE) {
winode = d_inode(upperdentry);
err = get_write_access(winode);
if (err)
goto out_drop_write;
}
inode_lock(upperdentry->d_inode);
err = notify_change(upperdentry, attr, NULL);
if (!err)
ovl_copyattr(upperdentry->d_inode, dentry->d_inode);
inode_unlock(upperdentry->d_inode);
if (winode)
put_write_access(winode);
}
out_drop_write:
ovl_drop_write(dentry);
out:
return err;
}
ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
const char *name, void *value, size_t size)
{
struct dentry *realdentry = ovl_dentry_real(dentry);
if (ovl_is_private_xattr(name))
return -ENODATA;
return vfs_getxattr(realdentry, name, value, size);
}
int ovl_xattr_get(struct dentry *dentry, const char *name,
void *value, size_t size)
{
struct dentry *realdentry = ovl_dentry_real(dentry);
ssize_t res;
const struct cred *old_cred;
old_cred = ovl_override_creds(dentry->d_sb);
res = vfs_getxattr(realdentry, name, value, size);
revert_creds(old_cred);
return res;
}
static const char *ovl_get_link(struct dentry *dentry,
struct inode *inode,
struct delayed_call *done)
{
const struct cred *old_cred;
const char *p;
if (!dentry)
return ERR_PTR(-ECHILD);
old_cred = ovl_override_creds(dentry->d_sb);
p = vfs_get_link(ovl_dentry_real(dentry), done);
revert_creds(old_cred);
return p;
}
static const char *ovl_get_link(struct dentry *dentry,
struct inode *inode,
struct delayed_call *done)
{
struct dentry *realdentry;
struct inode *realinode;
if (!dentry)
return ERR_PTR(-ECHILD);
realdentry = ovl_dentry_real(dentry);
realinode = realdentry->d_inode;
if (WARN_ON(!realinode->i_op->get_link))
return ERR_PTR(-EPERM);
return realinode->i_op->get_link(realdentry, realinode, done);
}