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/*
* vmfs-tools - Tools to access VMFS filesystems
* Copyright (C) 2009 Christophe Fillot <cf@utc.fr>
* Copyright (C) 2009,2011 Mike Hommey <mh@glandium.org>
*
* 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
* the Free Software Foundation, either version 2 of the License, or
* (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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* VMFS LVM layer
*/
#include <stdlib.h>
#include "vmfs.h"
/*
* Until we uncover the details of the segment descriptors format,
* it is useless to try to do something more efficient.
*/
static vmfs_volume_t *vmfs_lvm_get_extent_from_offset(const vmfs_lvm_t *lvm,
off_t pos)
{
int extent;
off_t segment = pos / VMFS_LVM_SEGMENT_SIZE;
for (extent = 0; extent < lvm->loaded_extents; extent++) {
if ((segment >= lvm->extents[extent]->vol_info.first_segment) &&
(segment <= lvm->extents[extent]->vol_info.last_segment))
return(lvm->extents[extent]);
}
return(NULL);
}
/* Get extent size */
static inline uint64_t vmfs_lvm_extent_size(const vmfs_volume_t *extent)
{
return((uint64_t)extent->vol_info.num_segments * VMFS_LVM_SEGMENT_SIZE);
}
typedef ssize_t (*vmfs_vol_io_func)(const vmfs_device_t *,off_t,u_char *,size_t);
/* Read a raw block of data on logical volume */
static inline ssize_t vmfs_lvm_io(const vmfs_lvm_t *lvm,off_t pos,u_char *buf,
size_t len,vmfs_vol_io_func func)
{
vmfs_volume_t *extent = vmfs_lvm_get_extent_from_offset(lvm,pos);
if (!extent)
return(-1);
pos -= (uint64_t)extent->vol_info.first_segment * VMFS_LVM_SEGMENT_SIZE;
if ((pos + len) > vmfs_lvm_extent_size(extent)) {
/* TODO: Handle this case */
fprintf(stderr,"VMFS: i/o spanned over several extents is unsupported\n");
return(-1);
}
return(func(&extent->dev,pos,buf,len));
}
/* Read a raw block of data on logical volume */
static ssize_t vmfs_lvm_read(const vmfs_device_t *dev,off_t pos,
u_char *buf,size_t len)
{
vmfs_lvm_t *lvm = (vmfs_lvm_t *)dev;
return(vmfs_lvm_io(lvm,pos,buf,len,vmfs_device_read));
}
/* Write a raw block of data on logical volume */
static ssize_t vmfs_lvm_write(const vmfs_device_t *dev,off_t pos,
const u_char *buf,size_t len)
{
vmfs_lvm_t *lvm = (vmfs_lvm_t *)dev;
return(vmfs_lvm_io(lvm,pos,(u_char *)buf,len,(vmfs_vol_io_func)vmfs_device_write));
}
/* Reserve the underlying volume given a LVM position */
static int vmfs_lvm_reserve(const vmfs_device_t *dev,off_t pos)
{
vmfs_lvm_t *lvm = (vmfs_lvm_t *)dev;
vmfs_volume_t *extent = vmfs_lvm_get_extent_from_offset(lvm,pos);
if (!extent)
return(-1);
return(vmfs_device_reserve(&extent->dev, 0));
}
/* Release the underlying volume given a LVM position */
static int vmfs_lvm_release(const vmfs_device_t *dev,off_t pos)
{
vmfs_lvm_t *lvm = (vmfs_lvm_t *)dev;
vmfs_volume_t *extent = vmfs_lvm_get_extent_from_offset(lvm,pos);
if (!extent)
return(-1);
return(vmfs_device_release(&extent->dev, 0));
}
/* Create a volume structure */
vmfs_lvm_t *vmfs_lvm_create(vmfs_flags_t flags)
{
vmfs_lvm_t *lvm;
if (!(lvm = calloc(1,sizeof(*lvm))))
return NULL;
lvm->flags = flags;
if (flags.read_write)
fprintf(stderr, "VMFS: R/W support is experimental. Use at your own risk\n");
return lvm;
}
/* Add an extent to the LVM */
int vmfs_lvm_add_extent(vmfs_lvm_t *lvm, vmfs_volume_t *vol)
{
uint32_t i;
if (!vol)
return(-1);
if (lvm->loaded_extents == 0) {
uuid_copy(lvm->lvm_info.uuid, vol->vol_info.lvm_uuid);
lvm->lvm_info.size = vol->vol_info.lvm_size;
lvm->lvm_info.blocks = vol->vol_info.blocks;
lvm->lvm_info.num_extents = vol->vol_info.num_extents;
} else if (uuid_compare(lvm->lvm_info.uuid, vol->vol_info.lvm_uuid)) {
fprintf(stderr, "VMFS: The %s file/device is not part of the LVM\n", vol->device);
return(-1);
} else if ((lvm->lvm_info.size != vol->vol_info.lvm_size) ||
(lvm->lvm_info.blocks != vol->vol_info.blocks) ||
(lvm->lvm_info.num_extents != vol->vol_info.num_extents)) {
fprintf(stderr, "VMFS: LVM information mismatch for the %s"
" file/device\n", vol->device);
return(-1);
}
for (i = 0;
(i < lvm->loaded_extents) &&
(vol->vol_info.first_segment > lvm->extents[i]->vol_info.first_segment);
i++);
if (lvm->loaded_extents)
memmove(&lvm->extents[i + 1], &lvm->extents[i],
(lvm->loaded_extents - i) * sizeof(vmfs_volume_t *));
lvm->extents[i] = vol;
lvm->loaded_extents++;
return(0);
}
/* Close an LVM */
static void vmfs_lvm_close(vmfs_device_t *dev)
{
vmfs_lvm_t *lvm = (vmfs_lvm_t *)dev;
if (!lvm)
return;
while(lvm->loaded_extents--)
vmfs_device_close(&lvm->extents[lvm->loaded_extents]->dev);
free(lvm);
}
/* Open an LVM */
int vmfs_lvm_open(vmfs_lvm_t *lvm)
{
if (!lvm->flags.allow_missing_extents &&
(lvm->loaded_extents != lvm->lvm_info.num_extents))
{
fprintf(stderr, "VMFS: Missing extents\n");
return(-1);
}
lvm->dev.read = vmfs_lvm_read;
if (lvm->flags.read_write)
lvm->dev.write = vmfs_lvm_write;
lvm->dev.reserve = vmfs_lvm_reserve;
lvm->dev.release = vmfs_lvm_release;
lvm->dev.close = vmfs_lvm_close;
lvm->dev.uuid = &lvm->lvm_info.uuid;
return(0);
}
/* Returns whether a given device is a vmfs_lvm */
bool vmfs_device_is_lvm(vmfs_device_t *dev)
{
return (dev->read == vmfs_lvm_read);
}
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