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/*-
* Copyright (c) 2014-2016 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
#if defined(__linux__)
#include <linux/falloc.h>
#include <sys/syscall.h>
#endif
/*
* __posix_std_fallocate --
* Linux fallocate call.
*/
static int
__posix_std_fallocate(
WT_FILE_HANDLE *file_handle, WT_SESSION *wt_session, wt_off_t offset)
{
#if defined(HAVE_FALLOCATE)
WT_DECL_RET;
WT_FILE_HANDLE_POSIX *pfh;
WT_UNUSED(wt_session);
pfh = (WT_FILE_HANDLE_POSIX *)file_handle;
WT_SYSCALL_RETRY(fallocate(pfh->fd, 0, (wt_off_t)0, offset), ret);
return (ret);
#else
WT_UNUSED(file_handle);
WT_UNUSED(wt_session);
WT_UNUSED(offset);
return (ENOTSUP);
#endif
}
/*
* __posix_sys_fallocate --
* Linux fallocate call (system call version).
*/
static int
__posix_sys_fallocate(
WT_FILE_HANDLE *file_handle, WT_SESSION *wt_session, wt_off_t offset)
{
#if defined(__linux__) && defined(SYS_fallocate)
WT_DECL_RET;
WT_FILE_HANDLE_POSIX *pfh;
WT_UNUSED(wt_session);
pfh = (WT_FILE_HANDLE_POSIX *)file_handle;
/*
* Try the system call for fallocate even if the C library wrapper was
* not found. The system call actually exists in the kernel for some
* Linux versions (RHEL 5.5), but not in the version of the C library.
* This allows it to work everywhere the kernel supports it.
*/
WT_SYSCALL_RETRY(
syscall(SYS_fallocate, pfh->fd, 0, (wt_off_t)0, offset), ret);
return (ret);
#else
WT_UNUSED(file_handle);
WT_UNUSED(wt_session);
WT_UNUSED(offset);
return (ENOTSUP);
#endif
}
/*
* __posix_posix_fallocate --
* POSIX fallocate call.
*/
static int
__posix_posix_fallocate(
WT_FILE_HANDLE *file_handle, WT_SESSION *wt_session, wt_off_t offset)
{
#if defined(HAVE_POSIX_FALLOCATE)
WT_DECL_RET;
WT_FILE_HANDLE_POSIX *pfh;
WT_UNUSED(wt_session);
pfh = (WT_FILE_HANDLE_POSIX *)file_handle;
WT_SYSCALL_RETRY(posix_fallocate(pfh->fd, (wt_off_t)0, offset), ret);
return (ret);
#else
WT_UNUSED(file_handle);
WT_UNUSED(wt_session);
WT_UNUSED(offset);
return (ENOTSUP);
#endif
}
/*
* __wt_posix_file_extend --
* Extend the file.
*/
int
__wt_posix_file_extend(
WT_FILE_HANDLE *file_handle, WT_SESSION *wt_session, wt_off_t offset)
{
/*
* The first file extension call: figure out what this system has.
*
* This function is configured as a locking call, so we know we're
* single-threaded through here. Set the nolock function first, then
* publish the NULL replacement to ensure the handle functions are
* always correct.
*
* We've seen Linux systems where posix_fallocate has corrupted existing
* file data (even though that is explicitly disallowed by POSIX).
* FreeBSD and Solaris support posix_fallocate, and so far we've seen
* no problems leaving it unlocked. Check for fallocate (and the system
* call version of fallocate) first to avoid locking on Linux if at all
* possible.
*/
if (__posix_std_fallocate(file_handle, wt_session, offset) == 0) {
file_handle->fh_extend_nolock = __posix_std_fallocate;
WT_PUBLISH(file_handle->fh_extend, NULL);
return (0);
}
if (__posix_sys_fallocate(file_handle, wt_session, offset) == 0) {
file_handle->fh_extend_nolock = __posix_sys_fallocate;
WT_PUBLISH(file_handle->fh_extend, NULL);
return (0);
}
if (__posix_posix_fallocate(file_handle, wt_session, offset) == 0) {
#if defined(__linux__)
file_handle->fh_extend = __posix_posix_fallocate;
WT_WRITE_BARRIER();
#else
file_handle->fh_extend_nolock = __posix_posix_fallocate;
WT_PUBLISH(file_handle->fh_extend, NULL);
#endif
return (0);
}
/*
* Use the POSIX ftruncate call if there's nothing else, it can extend
* files. Note ftruncate requires locking.
*/
if (file_handle->fh_truncate != NULL &&
file_handle->fh_truncate(file_handle, wt_session, offset) == 0) {
file_handle->fh_extend = file_handle->fh_truncate;
WT_WRITE_BARRIER();
return (0);
}
file_handle->fh_extend = NULL;
WT_WRITE_BARRIER();
return (ENOTSUP);
}
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