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![Alasdair G Kergon](/assets/img/avatar_default.png)
If you misuse the device-mapper interface (or there's a bug in your userspace tools) it's possible to end up with 'unlinked' mapped devices that cannot be removed until you reboot (along with uninterruptible processes). This patch prevents you from removing a device that is still open. It introduces dm_lock_for_deletion() which is called when a device is about to be removed to ensure that nothing has it open and nothing further can open it. It uses a private open_count for this which also lets us remove one of the problematic bdget_disk() calls elsewhere. Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
326 lines
10 KiB
C
326 lines
10 KiB
C
/*
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* Copyright (C) 2001 - 2003 Sistina Software (UK) Limited.
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* Copyright (C) 2004 - 2005 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the LGPL.
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*/
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#ifndef _LINUX_DM_IOCTL_V4_H
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#define _LINUX_DM_IOCTL_V4_H
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#include <linux/types.h>
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#define DM_DIR "mapper" /* Slashes not supported */
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#define DM_MAX_TYPE_NAME 16
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#define DM_NAME_LEN 128
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#define DM_UUID_LEN 129
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/*
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* A traditional ioctl interface for the device mapper.
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*
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* Each device can have two tables associated with it, an
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* 'active' table which is the one currently used by io passing
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* through the device, and an 'inactive' one which is a table
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* that is being prepared as a replacement for the 'active' one.
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*
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* DM_VERSION:
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* Just get the version information for the ioctl interface.
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*
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* DM_REMOVE_ALL:
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* Remove all dm devices, destroy all tables. Only really used
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* for debug.
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*
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* DM_LIST_DEVICES:
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* Get a list of all the dm device names.
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*
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* DM_DEV_CREATE:
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* Create a new device, neither the 'active' or 'inactive' table
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* slots will be filled. The device will be in suspended state
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* after creation, however any io to the device will get errored
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* since it will be out-of-bounds.
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*
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* DM_DEV_REMOVE:
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* Remove a device, destroy any tables.
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*
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* DM_DEV_RENAME:
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* Rename a device.
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*
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* DM_SUSPEND:
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* This performs both suspend and resume, depending which flag is
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* passed in.
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* Suspend: This command will not return until all pending io to
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* the device has completed. Further io will be deferred until
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* the device is resumed.
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* Resume: It is no longer an error to issue this command on an
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* unsuspended device. If a table is present in the 'inactive'
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* slot, it will be moved to the active slot, then the old table
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* from the active slot will be _destroyed_. Finally the device
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* is resumed.
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*
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* DM_DEV_STATUS:
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* Retrieves the status for the table in the 'active' slot.
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*
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* DM_DEV_WAIT:
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* Wait for a significant event to occur to the device. This
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* could either be caused by an event triggered by one of the
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* targets of the table in the 'active' slot, or a table change.
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*
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* DM_TABLE_LOAD:
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* Load a table into the 'inactive' slot for the device. The
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* device does _not_ need to be suspended prior to this command.
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*
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* DM_TABLE_CLEAR:
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* Destroy any table in the 'inactive' slot (ie. abort).
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*
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* DM_TABLE_DEPS:
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* Return a set of device dependencies for the 'active' table.
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*
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* DM_TABLE_STATUS:
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* Return the targets status for the 'active' table.
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*
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* DM_TARGET_MSG:
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* Pass a message string to the target at a specific offset of a device.
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*
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* DM_DEV_SET_GEOMETRY:
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* Set the geometry of a device by passing in a string in this format:
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*
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* "cylinders heads sectors_per_track start_sector"
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*
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* Beware that CHS geometry is nearly obsolete and only provided
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* for compatibility with dm devices that can be booted by a PC
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* BIOS. See struct hd_geometry for range limits. Also note that
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* the geometry is erased if the device size changes.
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*/
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/*
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* All ioctl arguments consist of a single chunk of memory, with
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* this structure at the start. If a uuid is specified any
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* lookup (eg. for a DM_INFO) will be done on that, *not* the
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* name.
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*/
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struct dm_ioctl {
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/*
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* The version number is made up of three parts:
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* major - no backward or forward compatibility,
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* minor - only backwards compatible,
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* patch - both backwards and forwards compatible.
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*
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* All clients of the ioctl interface should fill in the
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* version number of the interface that they were
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* compiled with.
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*
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* All recognised ioctl commands (ie. those that don't
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* return -ENOTTY) fill out this field, even if the
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* command failed.
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*/
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uint32_t version[3]; /* in/out */
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uint32_t data_size; /* total size of data passed in
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* including this struct */
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uint32_t data_start; /* offset to start of data
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* relative to start of this struct */
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uint32_t target_count; /* in/out */
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int32_t open_count; /* out */
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uint32_t flags; /* in/out */
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uint32_t event_nr; /* in/out */
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uint32_t padding;
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uint64_t dev; /* in/out */
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char name[DM_NAME_LEN]; /* device name */
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char uuid[DM_UUID_LEN]; /* unique identifier for
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* the block device */
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};
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/*
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* Used to specify tables. These structures appear after the
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* dm_ioctl.
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*/
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struct dm_target_spec {
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uint64_t sector_start;
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uint64_t length;
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int32_t status; /* used when reading from kernel only */
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/*
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* Location of the next dm_target_spec.
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* - When specifying targets on a DM_TABLE_LOAD command, this value is
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* the number of bytes from the start of the "current" dm_target_spec
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* to the start of the "next" dm_target_spec.
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* - When retrieving targets on a DM_TABLE_STATUS command, this value
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* is the number of bytes from the start of the first dm_target_spec
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* (that follows the dm_ioctl struct) to the start of the "next"
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* dm_target_spec.
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*/
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uint32_t next;
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char target_type[DM_MAX_TYPE_NAME];
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/*
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* Parameter string starts immediately after this object.
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* Be careful to add padding after string to ensure correct
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* alignment of subsequent dm_target_spec.
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*/
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};
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/*
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* Used to retrieve the target dependencies.
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*/
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struct dm_target_deps {
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uint32_t count; /* Array size */
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uint32_t padding; /* unused */
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uint64_t dev[0]; /* out */
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};
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/*
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* Used to get a list of all dm devices.
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*/
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struct dm_name_list {
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uint64_t dev;
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uint32_t next; /* offset to the next record from
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the _start_ of this */
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char name[0];
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};
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/*
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* Used to retrieve the target versions
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*/
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struct dm_target_versions {
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uint32_t next;
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uint32_t version[3];
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char name[0];
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};
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/*
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* Used to pass message to a target
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*/
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struct dm_target_msg {
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uint64_t sector; /* Device sector */
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char message[0];
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};
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/*
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* If you change this make sure you make the corresponding change
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* to dm-ioctl.c:lookup_ioctl()
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*/
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enum {
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/* Top level cmds */
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DM_VERSION_CMD = 0,
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DM_REMOVE_ALL_CMD,
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DM_LIST_DEVICES_CMD,
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/* device level cmds */
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DM_DEV_CREATE_CMD,
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DM_DEV_REMOVE_CMD,
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DM_DEV_RENAME_CMD,
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DM_DEV_SUSPEND_CMD,
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DM_DEV_STATUS_CMD,
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DM_DEV_WAIT_CMD,
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/* Table level cmds */
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DM_TABLE_LOAD_CMD,
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DM_TABLE_CLEAR_CMD,
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DM_TABLE_DEPS_CMD,
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DM_TABLE_STATUS_CMD,
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/* Added later */
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DM_LIST_VERSIONS_CMD,
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DM_TARGET_MSG_CMD,
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DM_DEV_SET_GEOMETRY_CMD
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};
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/*
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* The dm_ioctl struct passed into the ioctl is just the header
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* on a larger chunk of memory. On x86-64 and other
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* architectures the dm-ioctl struct will be padded to an 8 byte
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* boundary so the size will be different, which would change the
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* ioctl code - yes I really messed up. This hack forces these
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* architectures to have the correct ioctl code.
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*/
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#ifdef CONFIG_COMPAT
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typedef char ioctl_struct[308];
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#define DM_VERSION_32 _IOWR(DM_IOCTL, DM_VERSION_CMD, ioctl_struct)
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#define DM_REMOVE_ALL_32 _IOWR(DM_IOCTL, DM_REMOVE_ALL_CMD, ioctl_struct)
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#define DM_LIST_DEVICES_32 _IOWR(DM_IOCTL, DM_LIST_DEVICES_CMD, ioctl_struct)
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#define DM_DEV_CREATE_32 _IOWR(DM_IOCTL, DM_DEV_CREATE_CMD, ioctl_struct)
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#define DM_DEV_REMOVE_32 _IOWR(DM_IOCTL, DM_DEV_REMOVE_CMD, ioctl_struct)
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#define DM_DEV_RENAME_32 _IOWR(DM_IOCTL, DM_DEV_RENAME_CMD, ioctl_struct)
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#define DM_DEV_SUSPEND_32 _IOWR(DM_IOCTL, DM_DEV_SUSPEND_CMD, ioctl_struct)
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#define DM_DEV_STATUS_32 _IOWR(DM_IOCTL, DM_DEV_STATUS_CMD, ioctl_struct)
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#define DM_DEV_WAIT_32 _IOWR(DM_IOCTL, DM_DEV_WAIT_CMD, ioctl_struct)
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#define DM_TABLE_LOAD_32 _IOWR(DM_IOCTL, DM_TABLE_LOAD_CMD, ioctl_struct)
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#define DM_TABLE_CLEAR_32 _IOWR(DM_IOCTL, DM_TABLE_CLEAR_CMD, ioctl_struct)
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#define DM_TABLE_DEPS_32 _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, ioctl_struct)
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#define DM_TABLE_STATUS_32 _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, ioctl_struct)
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#define DM_LIST_VERSIONS_32 _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, ioctl_struct)
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#define DM_TARGET_MSG_32 _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, ioctl_struct)
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#define DM_DEV_SET_GEOMETRY_32 _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, ioctl_struct)
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#endif
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#define DM_IOCTL 0xfd
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#define DM_VERSION _IOWR(DM_IOCTL, DM_VERSION_CMD, struct dm_ioctl)
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#define DM_REMOVE_ALL _IOWR(DM_IOCTL, DM_REMOVE_ALL_CMD, struct dm_ioctl)
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#define DM_LIST_DEVICES _IOWR(DM_IOCTL, DM_LIST_DEVICES_CMD, struct dm_ioctl)
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#define DM_DEV_CREATE _IOWR(DM_IOCTL, DM_DEV_CREATE_CMD, struct dm_ioctl)
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#define DM_DEV_REMOVE _IOWR(DM_IOCTL, DM_DEV_REMOVE_CMD, struct dm_ioctl)
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#define DM_DEV_RENAME _IOWR(DM_IOCTL, DM_DEV_RENAME_CMD, struct dm_ioctl)
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#define DM_DEV_SUSPEND _IOWR(DM_IOCTL, DM_DEV_SUSPEND_CMD, struct dm_ioctl)
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#define DM_DEV_STATUS _IOWR(DM_IOCTL, DM_DEV_STATUS_CMD, struct dm_ioctl)
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#define DM_DEV_WAIT _IOWR(DM_IOCTL, DM_DEV_WAIT_CMD, struct dm_ioctl)
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#define DM_TABLE_LOAD _IOWR(DM_IOCTL, DM_TABLE_LOAD_CMD, struct dm_ioctl)
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#define DM_TABLE_CLEAR _IOWR(DM_IOCTL, DM_TABLE_CLEAR_CMD, struct dm_ioctl)
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#define DM_TABLE_DEPS _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, struct dm_ioctl)
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#define DM_TABLE_STATUS _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, struct dm_ioctl)
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#define DM_LIST_VERSIONS _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, struct dm_ioctl)
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#define DM_TARGET_MSG _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, struct dm_ioctl)
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#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
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#define DM_VERSION_MAJOR 4
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#define DM_VERSION_MINOR 7
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#define DM_VERSION_PATCHLEVEL 0
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#define DM_VERSION_EXTRA "-ioctl (2006-06-24)"
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/* Status bits */
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#define DM_READONLY_FLAG (1 << 0) /* In/Out */
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#define DM_SUSPEND_FLAG (1 << 1) /* In/Out */
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#define DM_PERSISTENT_DEV_FLAG (1 << 3) /* In */
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/*
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* Flag passed into ioctl STATUS command to get table information
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* rather than current status.
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*/
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#define DM_STATUS_TABLE_FLAG (1 << 4) /* In */
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/*
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* Flags that indicate whether a table is present in either of
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* the two table slots that a device has.
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*/
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#define DM_ACTIVE_PRESENT_FLAG (1 << 5) /* Out */
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#define DM_INACTIVE_PRESENT_FLAG (1 << 6) /* Out */
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/*
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* Indicates that the buffer passed in wasn't big enough for the
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* results.
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*/
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#define DM_BUFFER_FULL_FLAG (1 << 8) /* Out */
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/*
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* This flag is now ignored.
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*/
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#define DM_SKIP_BDGET_FLAG (1 << 9) /* In */
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/*
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* Set this to avoid attempting to freeze any filesystem when suspending.
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*/
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#define DM_SKIP_LOCKFS_FLAG (1 << 10) /* In */
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#endif /* _LINUX_DM_IOCTL_H */
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