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/*
* XFS preallocation support module .
*
* Copyright ( c ) James Peach 2006
*
* This program is free software ; you can redistribute it and / or modify
* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation ; either version 3 of the License , or
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* ( at your option ) any later version .
*
* This program is distributed in the hope that it will be useful ,
* but WITHOUT ANY WARRANTY ; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE . See the
* GNU General Public License for more details .
*
* You should have received a copy of the GNU General Public License
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* along with this program ; if not , see < http : //www.gnu.org/licenses/>.
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*/
# include "includes.h"
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# include "system/filesys.h"
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# include "smbd/smbd.h"
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/* Extent preallocation module.
*
* The purpose of this module is to preallocate space on the filesystem when
* we have a good idea of how large files are supposed to be . This lets writes
* proceed without having to allocate new extents and results in better file
* layouts on disk .
*
* Currently only implemented for XFS . This module is based on an original idea
* and implementation by Sebastian Brings .
*
* Tunables .
*
* prealloc : < ext > Number of bytes to preallocate for a file with
* the matching extension .
* prealloc : debug Debug level at which to emit messages .
*
* Example .
*
* prealloc : mpeg = 500 M # Preallocate * . mpeg to 500 MiB .
*/
# ifdef HAVE_XFS_LIBXFS_H
# include <xfs/libxfs.h>
# define lock_type xfs_flock64_t
# else
# define lock_type struct flock64
# endif
# define MODULE "prealloc"
static int module_debug ;
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static int preallocate_space ( int fd , off_t size )
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{
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int err ;
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lock_type fl = { 0 } ;
if ( size < = 0 ) {
return 0 ;
}
fl . l_whence = SEEK_SET ;
fl . l_start = 0 ;
fl . l_len = size ;
/* IMPORTANT: We use RESVSP because we want the extents to be
* allocated , but we don ' t want the allocation to show up in
* st_size or persist after the close ( 2 ) .
*/
# if defined(XFS_IOC_RESVSP64)
/* On Linux this comes in via libxfs.h. */
err = xfsctl ( NULL , fd , XFS_IOC_RESVSP64 , & fl ) ;
# elif defined(F_RESVSP64)
/* On IRIX, this comes from fcntl.h. */
err = fcntl ( fd , F_RESVSP64 , & fl ) ;
# else
err = - 1 ;
errno = ENOSYS ;
# endif
if ( err ) {
DEBUG ( module_debug ,
( " %s: preallocate failed on fd=%d size=%lld: %s \n " ,
MODULE , fd , ( long long ) size , strerror ( errno ) ) ) ;
}
return err ;
}
static int prealloc_connect (
struct vfs_handle_struct * handle ,
const char * service ,
const char * user )
{
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int ret = SMB_VFS_NEXT_CONNECT ( handle , service , user ) ;
if ( ret < 0 ) {
return ret ;
}
module_debug = lp_parm_int ( SNUM ( handle - > conn ) ,
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MODULE , " debug " , 100 ) ;
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return 0 ;
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}
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static int prealloc_openat ( struct vfs_handle_struct * handle ,
const struct files_struct * dirfsp ,
const struct smb_filename * smb_fname ,
files_struct * fsp ,
int flags ,
mode_t mode )
{
int fd ;
off_t size = 0 ;
const char * dot ;
char fext [ 10 ] ;
if ( ! ( flags & ( O_CREAT | O_TRUNC ) ) ) {
/* Caller is not intending to rewrite the file. Let's not mess
* with the allocation in this case .
*/
goto normal_open ;
}
* fext = ' \0 ' ;
dot = strrchr ( smb_fname - > base_name , ' . ' ) ;
if ( dot & & * + + dot ) {
if ( strlen ( dot ) < sizeof ( fext ) ) {
strncpy ( fext , dot , sizeof ( fext ) ) ;
if ( ! strnorm ( fext , CASE_LOWER ) ) {
goto normal_open ;
}
}
}
if ( * fext = = ' \0 ' ) {
goto normal_open ;
}
/* Syntax for specifying preallocation size is:
* MODULE : < extension > = < size >
* where
* < extension > is the file extension in lower case
* < size > is a size like 10 , 10 K , 10 M
*/
size = conv_str_size ( lp_parm_const_string ( SNUM ( handle - > conn ) , MODULE ,
fext , NULL ) ) ;
if ( size < = 0 ) {
/* No need to preallocate this file. */
goto normal_open ;
}
fd = SMB_VFS_NEXT_OPENAT ( handle , dirfsp , smb_fname , fsp , flags , mode ) ;
if ( fd < 0 ) {
return fd ;
}
/* Prellocate only if the file is being created or replaced. Note that
* Samba won ' t ever pass down O_TRUNC , which is why we have to handle
* truncate calls specially .
*/
if ( ( flags & O_CREAT ) | | ( flags & O_TRUNC ) ) {
off_t * psize ;
psize = VFS_ADD_FSP_EXTENSION ( handle , fsp , off_t , NULL ) ;
if ( psize = = NULL | | * psize = = - 1 ) {
return fd ;
}
DEBUG ( module_debug ,
( " %s: preallocating %s (fd=%d) to %lld bytes \n " ,
MODULE , smb_fname_str_dbg ( smb_fname ) , fd ,
( long long ) size ) ) ;
* psize = size ;
if ( preallocate_space ( fd , * psize ) < 0 ) {
VFS_REMOVE_FSP_EXTENSION ( handle , fsp ) ;
}
}
return fd ;
normal_open :
/* We are not creating or replacing a file. Skip the
* preallocation .
*/
DEBUG ( module_debug , ( " %s: skipping preallocation for %s \n " ,
MODULE , smb_fname_str_dbg ( smb_fname ) ) ) ;
return SMB_VFS_NEXT_OPENAT ( handle , dirfsp , smb_fname , fsp , flags , mode ) ;
}
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static int prealloc_ftruncate ( vfs_handle_struct * handle ,
files_struct * fsp ,
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off_t offset )
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{
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off_t * psize ;
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int ret = SMB_VFS_NEXT_FTRUNCATE ( handle , fsp , offset ) ;
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/* Maintain the allocated space even in the face of truncates. */
if ( ( psize = VFS_FETCH_FSP_EXTENSION ( handle , fsp ) ) ) {
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preallocate_space ( fsp_get_io_fd ( fsp ) , * psize ) ;
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}
return ret ;
}
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static struct vfs_fn_pointers prealloc_fns = {
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. openat_fn = prealloc_openat ,
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. ftruncate_fn = prealloc_ftruncate ,
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. connect_fn = prealloc_connect ,
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} ;
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static_decl_vfs ;
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NTSTATUS vfs_prealloc_init ( TALLOC_CTX * ctx )
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{
return smb_register_vfs ( SMB_VFS_INTERFACE_VERSION ,
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MODULE , & prealloc_fns ) ;
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}