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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2014 Red Hat
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifdef __linux__
#include <linux/falloc.h>
#endif
#include "FS.h"
#include "acconfig.h"
#ifdef HAVE_LIBXFS
#include "XFS.h"
#endif
#if defined(__APPLE__) || defined(__FreeBSD__)
#include <sys/mount.h>
#else
#include <sys/vfs.h>
#endif
#include "include/compat.h"
// ---------------
FS *FS::create(uint64_t f_type)
{
switch (f_type) {
#ifdef HAVE_LIBXFS
case XFS_SUPER_MAGIC:
return new XFS;
#endif
default:
return new FS;
}
}
FS *FS::create_by_fd(int fd)
{
struct statfs st;
::fstatfs(fd, &st);
return create(st.f_type);
}
// ---------------
int FS::set_alloc_hint(int fd, uint64_t hint)
{
return 0; // no-op
}
#ifdef HAVE_NAME_TO_HANDLE_AT
int FS::get_handle(int fd, std::string *h)
{
char buf[sizeof(struct file_handle) + MAX_HANDLE_SZ];
struct file_handle *fh = (struct file_handle *)buf;
int mount_id;
fh->handle_bytes = MAX_HANDLE_SZ;
int r = name_to_handle_at(fd, "", fh, &mount_id, AT_EMPTY_PATH);
if (r < 0) {
return -errno;
}
*h = std::string(buf, fh->handle_bytes + sizeof(struct file_handle));
return 0;
}
int FS::open_handle(int mount_fd, const std::string& h, int flags)
{
if (h.length() < sizeof(struct file_handle)) {
return -EINVAL;
}
struct file_handle *fh = (struct file_handle *)h.data();
if (fh->handle_bytes > h.length()) {
return -ERANGE;
}
int fd = open_by_handle_at(mount_fd, fh, flags);
if (fd < 0)
return -errno;
return fd;
}
#else // HAVE_NAME_TO_HANDLE_AT
int FS::get_handle(int fd, std::string *h)
{
return -EOPNOTSUPP;
}
int FS::open_handle(int mount_fd, const std::string& h, int flags)
{
return -EOPNOTSUPP;
}
#endif // HAVE_NAME_TO_HANDLE_AT
int FS::copy_file_range(int to_fd, uint64_t to_offset,
int from_fd,
uint64_t from_offset, uint64_t from_len)
{
ceph_abort_msg("write me");
}
int FS::zero(int fd, uint64_t offset, uint64_t length)
{
int r;
/*
From the fallocate(2) man page:
Specifying the FALLOC_FL_PUNCH_HOLE flag (available since Linux 2.6.38)
in mode deallocates space (i.e., creates a hole) in the byte range
starting at offset and continuing for len bytes. Within the specified
range, partial filesystem blocks are zeroed, and whole filesystem
blocks are removed from the file. After a successful call, subsequent
reads from this range will return zeroes.
The FALLOC_FL_PUNCH_HOLE flag must be ORed with FALLOC_FL_KEEP_SIZE in
mode; in other words, even when punching off the end of the file, the
file size (as reported by stat(2)) does not change.
Not all filesystems support FALLOC_FL_PUNCH_HOLE; if a filesystem
doesn't support the operation, an error is returned. The operation is
supported on at least the following filesystems:
* XFS (since Linux 2.6.38)
* ext4 (since Linux 3.0)
* Btrfs (since Linux 3.7)
* tmpfs (since Linux 3.5)
So: we only do this is PUNCH_HOLE *and* KEEP_SIZE are defined.
*/
#if !defined(__APPLE__) && !defined(__FreeBSD__)
# ifdef CEPH_HAVE_FALLOCATE
# ifdef FALLOC_FL_KEEP_SIZE
// first try fallocate
r = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, offset, length);
if (r < 0) {
r = -errno;
}
if (r != -EOPNOTSUPP) {
goto out; // a real error
}
// if that failed (-EOPNOTSUPP), fall back to writing zeros.
# endif
# endif
#endif
{
// fall back to writing zeros
ceph::bufferlist bl;
bl.append_zero(length);
r = ::lseek64(fd, offset, SEEK_SET);
if (r < 0) {
r = -errno;
goto out;
}
r = bl.write_fd(fd);
}
out:
return r;
}
// ---------------
|
