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lvm2/tools/vgextend.c
David Teigland 1e2420bca8 commands: new method for defining commands
. Define a prototype for every lvm command.
. Match every user command with one definition.
. Generate help text and man pages from them.

The new file command-lines.in defines a prototype for every
unique lvm command.  A unique lvm command is a unique
combination of: command name + required option args +
required positional args.  Each of these prototypes also
includes the optional option args and optional positional
args that the command will accept, a description, and a
unique string ID for the definition.  Any valid command
will match one of the prototypes.

Here's an example of the lvresize command definitions from
command-lines.in, there are three unique lvresize commands:

lvresize --size SizeMB LV
OO: --alloc Alloc, --autobackup Bool, --force,
--nofsck, --nosync, --noudevsync, --reportformat String, --resizefs,
--stripes Number, --stripesize SizeKB, --poolmetadatasize SizeMB
OP: PV ...
ID: lvresize_by_size
DESC: Resize an LV by a specified size.

lvresize LV PV ...
OO: --alloc Alloc, --autobackup Bool, --force,
--nofsck, --nosync, --noudevsync,
--reportformat String, --resizefs, --stripes Number, --stripesize SizeKB
ID: lvresize_by_pv
DESC: Resize an LV by specified PV extents.
FLAGS: SECONDARY_SYNTAX

lvresize --poolmetadatasize SizeMB LV_thinpool
OO: --alloc Alloc, --autobackup Bool, --force,
--nofsck, --nosync, --noudevsync,
--reportformat String, --stripes Number, --stripesize SizeKB
OP: PV ...
ID: lvresize_pool_metadata_by_size
DESC: Resize a pool metadata SubLV by a specified size.

The three commands have separate definitions because they have
different required parameters.  Required parameters are specified
on the first line of the definition.  Optional options are
listed after OO, and optional positional args are listed after OP.

This data is used to generate corresponding command definition
structures for lvm in command-lines.h.  usage/help output is also
auto generated, so it is always in sync with the definitions.

Every user-entered command is compared against the set of
command structures, and matched with one.  An error is
reported if an entered command does not have the required
parameters for any definition.  The closest match is printed
as a suggestion, and running lvresize --help will display
the usage for each possible lvresize command.

The prototype syntax used for help/man output includes
required --option and positional args on the first line,
and optional --option and positional args enclosed in [ ]
on subsequent lines.

  command_name <required_opt_args> <required_pos_args>
          [ <optional_opt_args> ]
          [ <optional_pos_args> ]

Command definitions that are not to be advertised/suggested
have the flag SECONDARY_SYNTAX.  These commands will not be
printed in the normal help output.

Man page prototypes are also generated from the same original
command definitions, and are always in sync with the code
and help text.

Very early in command execution, a matching command definition
is found.  lvm then knows the operation being done, and that
the provided args conform to the definition.  This will allow
lots of ad hoc checking/validation to be removed throughout
the code.

Each command definition can also be routed to a specific
function to implement it.  The function is associated with
an enum value for the command definition (generated from
the ID string.)  These per-command-definition implementation
functions have not yet been created, so all commands
currently fall back to the existing per-command-name
implementation functions.

Using per-command-definition functions will allow lots of
code to be removed which tries to figure out what the
command is meant to do.  This is currently based on ad hoc
and complicated option analysis.  When using the new
functions, what the command is doing is already known
from the associated command definition.
2017-02-13 08:20:10 -06:00

204 lines
5.3 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2009 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "tools.h"
struct vgextend_params {
struct pvcreate_params pp;
};
static int _restore_pv(struct volume_group *vg, const char *pv_name)
{
struct pv_list *pvl = NULL;
pvl = find_pv_in_vg(vg, pv_name);
if (!pvl) {
log_warn("WARNING: PV %s not found in VG %s", pv_name, vg->name);
return 0;
}
if (!(pvl->pv->status & MISSING_PV)) {
log_warn("WARNING: PV %s was not missing in VG %s", pv_name, vg->name);
return 0;
}
if (!pvl->pv->dev) {
log_warn("WARNING: The PV %s is still missing.", pv_name);
return 0;
}
pvl->pv->status &= ~MISSING_PV;
return 1;
}
static int _vgextend_restoremissing(struct cmd_context *cmd __attribute__((unused)),
const char *vg_name, struct volume_group *vg,
struct processing_handle *handle)
{
struct vgextend_params *vp = (struct vgextend_params *) handle->custom_handle;
struct pvcreate_params *pp = &vp->pp;
int fixed = 0;
unsigned i;
if (!archive(vg))
return_0;
for (i = 0; i < pp->pv_count; i++)
if (_restore_pv(vg, pp->pv_names[i]))
fixed++;
if (!fixed) {
log_error("No PV has been restored.");
return ECMD_FAILED;
}
if (!vg_write(vg) || !vg_commit(vg))
return_ECMD_FAILED;
backup(vg);
log_print_unless_silent("Volume group \"%s\" successfully extended", vg_name);
return ECMD_PROCESSED;
}
static int _vgextend_single(struct cmd_context *cmd, const char *vg_name,
struct volume_group *vg, struct processing_handle *handle)
{
struct vgextend_params *vp = (struct vgextend_params *) handle->custom_handle;
struct pvcreate_params *pp = &vp->pp;
uint32_t mda_copies;
uint32_t mda_used;
int ret = ECMD_FAILED;
if (arg_is_set(cmd, metadataignore_ARG) &&
(pp->force == PROMPT) && !pp->yes &&
(vg_mda_copies(vg) != VGMETADATACOPIES_UNMANAGED) &&
(yes_no_prompt("Override preferred number of copies of VG %s metadata? [y/n]: ", vg_name) == 'n')) {
log_error("Volume group %s not changed", vg_name);
return ECMD_FAILED;
}
if (!archive(vg))
return_ECMD_FAILED;
if (!vg_extend_each_pv(vg, pp))
goto_out;
if (arg_is_set(cmd, metadataignore_ARG)) {
mda_copies = vg_mda_copies(vg);
mda_used = vg_mda_used_count(vg);
if ((mda_copies != VGMETADATACOPIES_UNMANAGED) &&
(mda_copies != mda_used)) {
log_warn("WARNING: Changing preferred number of copies of VG %s metadata from %"PRIu32" to %"PRIu32,
vg_name, mda_copies, mda_used);
vg_set_mda_copies(vg, mda_used);
}
}
log_verbose("Volume group \"%s\" will be extended by %d new physical volumes", vg_name, pp->pv_count);
if (!vg_write(vg) || !vg_commit(vg))
goto_out;
backup(vg);
log_print_unless_silent("Volume group \"%s\" successfully extended", vg_name);
ret = ECMD_PROCESSED;
out:
return ret;
}
int vgextend(struct cmd_context *cmd, int argc, char **argv)
{
struct processing_handle *handle;
struct vgextend_params vp;
struct pvcreate_params *pp = &vp.pp;
unsigned restoremissing = arg_is_set(cmd, restoremissing_ARG);
const char *vg_name;
int ret;
if (!argc) {
log_error("Please enter volume group name and "
"physical volume(s)");
return EINVALID_CMD_LINE;
}
vg_name = skip_dev_dir(cmd, argv[0], NULL);
argc--;
argv++;
pvcreate_params_set_defaults(pp);
if (!pvcreate_params_from_args(cmd, pp))
return EINVALID_CMD_LINE;
pp->pv_count = argc;
pp->pv_names = argv;
/* Don't create a new PV on top of an existing PV like pvcreate does. */
pp->preserve_existing = 1;
/* pvcreate within vgextend cannot be forced. */
pp->force = 0;
/*
* Needed to change the set of orphan PVs.
* (disable afterward to prevent process_each_pv from doing
* a shared global lock since it's already acquired it ex.)
*/
if (!lockd_gl(cmd, "ex", 0))
return_ECMD_FAILED;
cmd->lockd_gl_disable = 1;
if (!(handle = init_processing_handle(cmd, NULL))) {
log_error("Failed to initialize processing handle.");
return ECMD_FAILED;
}
if (!restoremissing) {
if (!pvcreate_each_device(cmd, handle, pp)) {
destroy_processing_handle(cmd, handle);
return_ECMD_FAILED;
}
}
/*
* pvcreate_each_device returns with the VG_ORPHANS write lock held,
* which was used to do pvcreate. Now to create the VG using those
* PVs, the VG lock will be taken (with the orphan lock already held.)
*/
/*
* It is always ok to add new PVs to a VG - even if there are
* missing PVs. No LVs are affected by this operation, but
* repair processes - particularly for RAID segtypes - can
* be facilitated.
*/
cmd->handles_missing_pvs = 1;
handle->custom_handle = &vp;
ret = process_each_vg(cmd, 0, NULL, vg_name, NULL,
READ_FOR_UPDATE, 0, handle,
restoremissing ? &_vgextend_restoremissing : &_vgextend_single);
destroy_processing_handle(cmd, handle);
if (!restoremissing)
unlock_vg(cmd, NULL, VG_ORPHANS);
return ret;
}