static struct dentry *ovl_clear_empty(struct dentry *dentry, struct list_head *list) { struct dentry *workdir = ovl_workdir(dentry); struct inode *wdir = workdir->d_inode; struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); struct inode *udir = upperdir->d_inode; struct path upperpath; struct dentry *upper; struct dentry *opaquedir; struct kstat stat; int err; if (WARN_ON(!workdir)) return ERR_PTR(-EROFS); err = ovl_lock_rename_workdir(workdir, upperdir); if (err) goto out; ovl_path_upper(dentry, &upperpath); err = vfs_getattr(&upperpath, &stat, STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); if (err) goto out_unlock; err = -ESTALE; if (!S_ISDIR(stat.mode)) goto out_unlock; upper = upperpath.dentry; if (upper->d_parent->d_inode != udir) goto out_unlock; opaquedir = ovl_create_temp(workdir, OVL_CATTR(stat.mode)); err = PTR_ERR(opaquedir); if (IS_ERR(opaquedir)) goto out_unlock; err = ovl_copy_xattr(upper, opaquedir); if (err) goto out_cleanup; err = ovl_set_opaque(dentry, opaquedir); if (err) goto out_cleanup; inode_lock(opaquedir->d_inode); err = ovl_set_attr(opaquedir, &stat); inode_unlock(opaquedir->d_inode); if (err) goto out_cleanup; err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); if (err) goto out_cleanup; ovl_cleanup_whiteouts(upper, list); ovl_cleanup(wdir, upper); unlock_rename(workdir, upperdir); /* dentry's upper doesn't match now, get rid of it */ d_drop(dentry); return opaquedir; out_cleanup: ovl_cleanup(wdir, opaquedir); dput(opaquedir); out_unlock: unlock_rename(workdir, upperdir); out: return ERR_PTR(err); }
static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, const char *name, bool persist) { struct inode *dir = ofs->workbasedir->d_inode; struct vfsmount *mnt = ofs->upper_mnt; struct dentry *work; int err; bool retried = false; bool locked = false; inode_lock_nested(dir, I_MUTEX_PARENT); locked = true; retry: work = lookup_one_len(name, ofs->workbasedir, strlen(name)); if (!IS_ERR(work)) { struct iattr attr = { .ia_valid = ATTR_MODE, .ia_mode = S_IFDIR | 0, }; if (work->d_inode) { err = -EEXIST; if (retried) goto out_dput; if (persist) goto out_unlock; retried = true; ovl_workdir_cleanup(dir, mnt, work, 0); dput(work); goto retry; } work = ovl_create_real(dir, work, OVL_CATTR(attr.ia_mode)); err = PTR_ERR(work); if (IS_ERR(work)) goto out_err; /* * Try to remove POSIX ACL xattrs from workdir. We are good if: * * a) success (there was a POSIX ACL xattr and was removed) * b) -ENODATA (there was no POSIX ACL xattr) * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) * * There are various other error values that could effectively * mean that the xattr doesn't exist (e.g. -ERANGE is returned * if the xattr name is too long), but the set of filesystems * allowed as upper are limited to "normal" ones, where checking * for the above two errors is sufficient. */ err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT); if (err && err != -ENODATA && err != -EOPNOTSUPP) goto out_dput; err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS); if (err && err != -ENODATA && err != -EOPNOTSUPP) goto out_dput; /* Clear any inherited mode bits */ inode_lock(work->d_inode); err = notify_change(work, &attr, NULL); inode_unlock(work->d_inode); if (err) goto out_dput; } else { err = PTR_ERR(work); goto out_err; } out_unlock: if (locked) inode_unlock(dir); return work; out_dput: dput(work); out_err: pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n", ofs->config.workdir, name, -err); work = NULL; goto out_unlock; }