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/*
* vmfs-tools - Tools to access VMFS filesystems
* Copyright (C) 2009 Christophe Fillot <cf@utc.fr>
* Copyright (C) 2009 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 metadata headers.
*/
#include <string.h>
#include <sys/stat.h>
#include "vmfs.h"
/* Read a metadata header */
int vmfs_metadata_hdr_read(vmfs_metadata_hdr_t *mdh,const u_char *buf)
{
mdh->magic = read_le32(buf,VMFS_MDH_OFS_MAGIC);
mdh->pos = read_le64(buf,VMFS_MDH_OFS_POS);
mdh->hb_pos = read_le64(buf,VMFS_MDH_OFS_HB_POS);
mdh->hb_seq = read_le64(buf,VMFS_MDH_OFS_HB_SEQ);
mdh->obj_seq = read_le64(buf,VMFS_MDH_OFS_OBJ_SEQ);
mdh->hb_lock = read_le32(buf,VMFS_MDH_OFS_HB_LOCK);
mdh->mtime = read_le64(buf,VMFS_MDH_OFS_MTIME);
read_uuid(buf,VMFS_MDH_OFS_HB_UUID,&mdh->hb_uuid);
return(0);
}
/* Write a metadata header */
int vmfs_metadata_hdr_write(const vmfs_metadata_hdr_t *mdh,u_char *buf)
{
memset(buf,0,VMFS_METADATA_HDR_SIZE);
write_le32(buf,VMFS_MDH_OFS_MAGIC,mdh->magic);
write_le64(buf,VMFS_MDH_OFS_POS,mdh->pos);
write_le64(buf,VMFS_MDH_OFS_HB_POS,mdh->hb_pos);
write_le64(buf,VMFS_MDH_OFS_HB_SEQ,mdh->hb_seq);
write_le64(buf,VMFS_MDH_OFS_OBJ_SEQ,mdh->obj_seq);
write_le32(buf,VMFS_MDH_OFS_HB_LOCK,mdh->hb_lock);
write_le64(buf,VMFS_MDH_OFS_MTIME,mdh->mtime);
write_uuid(buf,VMFS_MDH_OFS_HB_UUID,&mdh->hb_uuid);
return(0);
}
/* Lock and read metadata at specified position */
int vmfs_metadata_lock(vmfs_fs_t *fs,off_t pos,u_char *buf,size_t buf_len,
vmfs_metadata_hdr_t *mdh)
{
/* Acquire heartbeat */
if (vmfs_heartbeat_acquire(fs) == -1)
return(-1);
/* Reserve volume */
if (vmfs_device_reserve(fs->dev,pos) == -1) {
fprintf(stderr,"VMFS: unable to reserve volume.\n");
goto err_reserve;
}
/* Read the complete metadata for the caller */
if (vmfs_device_read(fs->dev,pos,buf,buf_len) != buf_len) {
fprintf(stderr,"VMFS: unable to read metadata.\n");
goto err_io;
}
vmfs_metadata_hdr_read(mdh,buf);
if (mdh->hb_lock != 0)
goto err_io;
/* Update metadata information */
mdh->obj_seq++;
mdh->hb_lock = 1;
mdh->hb_pos = fs->hb.pos;
mdh->hb_seq = fs->hb_seq;
uuid_copy(mdh->hb_uuid,fs->hb.uuid);
vmfs_metadata_hdr_write(mdh,buf);
/* Rewrite the metadata header only */
if (vmfs_device_write(fs->dev,pos,buf,VMFS_METADATA_HDR_SIZE)
!= VMFS_METADATA_HDR_SIZE)
{
fprintf(stderr,"VMFS: unable to write metadata header.\n");
goto err_io;
}
vmfs_device_release(fs->dev,pos);
return(0);
err_io:
vmfs_device_release(fs->dev,pos);
err_reserve:
vmfs_heartbeat_release(fs);
return(-1);
}
/* Unlock metadata */
int vmfs_metadata_unlock(vmfs_fs_t *fs,vmfs_metadata_hdr_t *mdh)
{
DECL_ALIGNED_BUFFER(buf,VMFS_METADATA_HDR_SIZE);
mdh->hb_lock = 0;
uuid_clear(mdh->hb_uuid);
vmfs_metadata_hdr_write(mdh,buf);
/* Rewrite the metadata header only */
if (vmfs_device_write(fs->dev,mdh->pos,buf,buf_len) != buf_len)
{
fprintf(stderr,"VMFS: unable to write metadata header.\n");
return(-1);
}
return(vmfs_heartbeat_release(fs));
}
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