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lvm2/liblvm/lvm.h
Dave Wysochanski a0b1b1872e Change default errno value to 0 (no error) and add prototypes in lvm.h
Since we are using errno values, we should use '0' as a default value
which indicates a non-error, rather than defining some made-up default
value that is not defined in errno.  If we need to deviate from errno
values, this will most likely indicate a flaw in our design.

Add prototypes for lvm_errno and lvm_errmsg inside lvm.h and provide
a basic description of their function.  This fixes a couple compile
warnings.


Author: Dave Wysochanski <dwysocha@redhat.com>
2009-07-16 03:07:45 +00:00

194 lines
5.3 KiB
C

/*
* Copyright (C) 2008,2009 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _LIB_LVM_H
#define _LIB_LVM_H
#include "lvm-version.h"
#include <stdint.h>
/* Internal object structures */
struct volume_group;
struct physical_volume;
struct logical_volume;
struct lv_segment;
struct pv_segment;
/* liblvm handles to objects pv, vg, lv, pvseg, lvseg */
typedef struct volume_group vg_t;
typedef struct physical_volume pv_t;
typedef struct logical_volume lv_t;
typedef struct pv_segment pvseg_t;
typedef struct lv_segment lvseg_t;
struct lvm; /* internal data */
/**
* The lvm handle.
*/
typedef struct lvm *lvm_t;
/**
* Create a LVM handle.
*
* Once all LVM operations have been completed, use lvm_destroy to release
* the handle and any associated resources.
*
* \param system_dir
* Set an alternative LVM system directory. Use NULL to use the
* default value. If the environment variable LVM_SYSTEM_DIR is set,
* it will override any LVM system directory setting.
* \return A valid LVM handle is returned or NULL if there has been a
* memory allocation problem. You have to check if an error occured
* with the lvm_error function.
*/
lvm_t lvm_create(const char *system_dir);
/**
* Destroy a LVM handle allocated with lvm_create.
*
* \param libh
* Handle obtained from lvm_create.
*/
void lvm_destroy(lvm_t libh);
/**
* Reload the original configuration from the system directory.
*
* \param libh
* Handle obtained from lvm_create.
*/
int lvm_reload_config(lvm_t libh);
/**
* Return stored error no describing last LVM API error.
*
* Users of liblvm should use lvm_errno to determine success or failure
* of the last call, unless the API indicates another method of determining
* success or failure.
*
* \param libh
* Handle obtained from lvm_create.
*
* \return An errno value describing the last LVM error.
*/
int lvm_errno(lvm_t libh);
/**
* Return stored error message describing last LVM error.
*
* \param libh
* Handle obtained from lvm_create.
*
* \return An error string describing the last LVM error.
*/
const char *lvm_errmsg(lvm_t libh);
/**
* Create a VG with default parameters.
*
* This API requires calling lvm_vg_write to commit the change to disk.
* Upon success, other APIs may be used to set non-default parameters.
* For example, to set a non-default extent size, use lvm_vg_set_extent_size.
* Next, to add physical storage devices to the volume group, use
* lvm_vg_extend for each device.
* Once all parameters are set appropriately and all devices are added to the
* VG, use lvm_vg_write to commit the new VG to disk, and lvm_vg_close to
* release the VG handle.
*
* \param libh
* Handle obtained from lvm_create.
*
* \return A VG handle with error code set appropriately.
* FIXME: Update error handling description after errno and logging patches
*/
vg_t *lvm_vg_create(lvm_t libh, const char *vg_name);
/**
* Extend a VG by adding a device.
*
* This API requires calling lvm_vg_write to commit the change to disk.
* After successfully adding a device, use lvm_vg_write to commit the new VG
* to disk. Upon failure, retry the operation or release the VG handle with
* lvm_vg_close.
*
* \param vg
* VG handle obtained from lvm_vg_create.
*
* \param device
* Name of device to add to VG.
*
* \return Status code of 1 (success) or 0 (failure).
*/
int lvm_vg_extend(vg_t *vg, const char *device);
/**
* Set the extent size of a VG.
*
* This API requires calling lvm_vg_write to commit the change to disk.
* After successfully setting a new extent size, use lvm_vg_write to commit
* the new VG to disk. Upon failure, retry the operation or release the VG
* handle with lvm_vg_close.
*
* \param vg
* VG handle obtained from lvm_vg_create.
*
* \param new_size
* New extent size to set (in sectors).
*
* \return Status code of 1 (success) or 0 (failure).
*/
int lvm_vg_set_extent_size(vg_t *vg, uint32_t new_size);
/**
* Write a VG to disk.
*
* This API commits the VG to disk.
* Upon failure, retry the operation and/or release the VG handle with
* lvm_vg_close.
*
* \param vg
* VG handle obtained from lvm_vg_create.
*
* \return Status code of 1 (success) or 0 (failure).
*/
int lvm_vg_write(vg_t *vg);
/**
* Remove a VG from the system.
*
* This API commits the change to disk and does not require calling
* lvm_vg_write.
*
* \param vg
* VG handle obtained from lvm_vg_create.
*
* \return Status code of 1 (success) or 0 (failure).
*/
int lvm_vg_remove(vg_t *vg);
/**
* Close a VG opened with lvm_vg_create
*
* This API releases a VG handle and any resources associated with the handle.
*
* \param vg
* VG handle obtained from lvm_vg_create.
*
* \return Status code of 1 (success) or 0 (failure).
*/
int lvm_vg_close(vg_t *vg);
#endif /* _LIB_LVM_H */