static int ovl_copy_up_last(struct dentry *dentry, struct iattr *attr,
bool no_data)
{
int err;
struct dentry *parent;
struct kstat stat;
struct path lowerpath;
parent = dget_parent(dentry);
err = ovl_copy_up(parent);
if (err)
goto out_dput_parent;
ovl_path_lower(dentry, &lowerpath);
err = vfs_getattr(&lowerpath, &stat);
if (err)
goto out_dput_parent;
if (no_data)
stat.size = 0;
err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat, attr);
out_dput_parent:
dput(parent);
return err;
}
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;
}
enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
{
enum ovl_path_type type = ovl_path_type(dentry);
if (type == OVL_PATH_LOWER)
ovl_path_lower(dentry, path);
else
ovl_path_upper(dentry, path);
return type;
}
static int ovl_copy_up_truncate(struct dentry *dentry)
{
int err;
struct dentry *parent;
struct kstat stat;
struct path lowerpath;
parent = dget_parent(dentry);
err = ovl_copy_up(parent);
if (err)
goto out_dput_parent;
ovl_path_lower(dentry, &lowerpath);
err = vfs_getattr(&lowerpath, &stat);
if (err)
goto out_dput_parent;
stat.size = 0;
err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat);
out_dput_parent:
dput(parent);
return err;
}
int ovl_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int flags)
{
struct dentry *dentry = path->dentry;
enum ovl_path_type type;
struct path realpath;
const struct cred *old_cred;
bool is_dir = S_ISDIR(dentry->d_inode->i_mode);
int err;
type = ovl_path_real(dentry, &realpath);
old_cred = ovl_override_creds(dentry->d_sb);
err = vfs_getattr(&realpath, stat, request_mask, flags);
if (err)
goto out;
/*
* When all layers are on the same fs, all real inode number are
* unique, so we use the overlay st_dev, which is friendly to du -x.
*
* We also use st_ino of the copy up origin, if we know it.
* This guaranties constant st_dev/st_ino across copy up.
*
* If filesystem supports NFS export ops, this also guaranties
* persistent st_ino across mount cycle.
*/
if (ovl_same_sb(dentry->d_sb)) {
if (OVL_TYPE_ORIGIN(type)) {
struct kstat lowerstat;
u32 lowermask = STATX_INO | (!is_dir ? STATX_NLINK : 0);
ovl_path_lower(dentry, &realpath);
err = vfs_getattr(&realpath, &lowerstat,
lowermask, flags);
if (err)
goto out;
WARN_ON_ONCE(stat->dev != lowerstat.dev);
/*
* Lower hardlinks may be broken on copy up to different
* upper files, so we cannot use the lower origin st_ino
* for those different files, even for the same fs case.
* With inodes index enabled, it is safe to use st_ino
* of an indexed hardlinked origin. The index validates
* that the upper hardlink is not broken.
*/
if (is_dir || lowerstat.nlink == 1 ||
ovl_test_flag(OVL_INDEX, d_inode(dentry)))
stat->ino = lowerstat.ino;
}
stat->dev = dentry->d_sb->s_dev;
} else if (is_dir) {
/*
* If not all layers are on the same fs the pair {real st_ino;
* overlay st_dev} is not unique, so use the non persistent
* overlay st_ino.
*
* Always use the overlay st_dev for directories, so 'find
* -xdev' will scan the entire overlay mount and won't cross the
* overlay mount boundaries.
*/
stat->dev = dentry->d_sb->s_dev;
stat->ino = dentry->d_inode->i_ino;
}
/*
* It's probably not worth it to count subdirs to get the
* correct link count. nlink=1 seems to pacify 'find' and
* other utilities.
*/
if (is_dir && OVL_TYPE_MERGE(type))
stat->nlink = 1;
/*
* Return the overlay inode nlinks for indexed upper inodes.
* Overlay inode nlink counts the union of the upper hardlinks
* and non-covered lower hardlinks. It does not include the upper
* index hardlink.
*/
if (!is_dir && ovl_test_flag(OVL_INDEX, d_inode(dentry)))
stat->nlink = dentry->d_inode->i_nlink;
out:
revert_creds(old_cred);
return err;
}
