Commit 238c6d54 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
  dm snapshot: extend exception store functions
  dm snapshot: split out exception store implementations
  dm snapshot: rename struct exception_store
  dm snapshot: separate out exception store interface
  dm mpath: move trigger_event to system workqueue
  dm: add name and uuid to sysfs
  dm table: rework reference counting
  dm: support barriers on simple devices
  dm request: extend target interface
  dm request: add caches
  dm ioctl: allow dm_copy_name_and_uuid to return only one field
  dm log: ensure log bitmap fits on log device
  dm log: move region_size validation
  dm log: avoid reinitialising io_req on every operation
  dm: consolidate target deregistration error handling
  dm raid1: fix error count
  dm log: fix dm_io_client leak on error paths
  dm snapshot: change yield to msleep
  dm table: drop reference at unbind
parents 8e128ce3 a159c1ac
......@@ -3,9 +3,10 @@
#
dm-mod-objs := dm.o dm-table.o dm-target.o dm-linear.o dm-stripe.o \
dm-ioctl.o dm-io.o dm-kcopyd.o
dm-ioctl.o dm-io.o dm-kcopyd.o dm-sysfs.o
dm-multipath-objs := dm-path-selector.o dm-mpath.o
dm-snapshot-objs := dm-snap.o dm-exception-store.o
dm-snapshot-objs := dm-snap.o dm-exception-store.o dm-snap-transient.o \
dm-snap-persistent.o
dm-mirror-objs := dm-raid1.o
md-mod-objs := md.o bitmap.o
raid456-objs := raid5.o raid6algos.o raid6recov.o raid6tables.o \
......
......@@ -1322,11 +1322,7 @@ static int __init dm_crypt_init(void)
static void __exit dm_crypt_exit(void)
{
int r = dm_unregister_target(&crypt_target);
if (r < 0)
DMERR("unregister failed %d", r);
dm_unregister_target(&crypt_target);
kmem_cache_destroy(_crypt_io_pool);
}
......
......@@ -364,11 +364,7 @@ static int __init dm_delay_init(void)
static void __exit dm_delay_exit(void)
{
int r = dm_unregister_target(&delay_target);
if (r < 0)
DMERR("unregister failed %d", r);
dm_unregister_target(&delay_target);
kmem_cache_destroy(delayed_cache);
destroy_workqueue(kdelayd_wq);
}
......
/*
* dm-exception-store.c
*
* Copyright (C) 2001-2002 Sistina Software (UK) Limited.
* Copyright (C) 2006 Red Hat GmbH
* Copyright (C) 2006-2008 Red Hat GmbH
*
* This file is released under the GPL.
*/
#include "dm-snap.h"
#include "dm-exception-store.h"
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/dm-io.h>
#include <linux/dm-kcopyd.h>
#define DM_MSG_PREFIX "snapshots"
#define DM_CHUNK_SIZE_DEFAULT_SECTORS 32 /* 16KB */
/*-----------------------------------------------------------------
* Persistent snapshots, by persistent we mean that the snapshot
* will survive a reboot.
*---------------------------------------------------------------*/
/*
* We need to store a record of which parts of the origin have
* been copied to the snapshot device. The snapshot code
* requires that we copy exception chunks to chunk aligned areas
* of the COW store. It makes sense therefore, to store the
* metadata in chunk size blocks.
*
* There is no backward or forward compatibility implemented,
* snapshots with different disk versions than the kernel will
* not be usable. It is expected that "lvcreate" will blank out
* the start of a fresh COW device before calling the snapshot
* constructor.
*
* The first chunk of the COW device just contains the header.
* After this there is a chunk filled with exception metadata,
* followed by as many exception chunks as can fit in the
* metadata areas.
*
* All on disk structures are in little-endian format. The end
* of the exceptions info is indicated by an exception with a
* new_chunk of 0, which is invalid since it would point to the
* header chunk.
*/
/*
* Magic for persistent snapshots: "SnAp" - Feeble isn't it.
*/
#define SNAP_MAGIC 0x70416e53
/*
* The on-disk version of the metadata.
*/
#define SNAPSHOT_DISK_VERSION 1
struct disk_header {
uint32_t magic;
/*
* Is this snapshot valid. There is no way of recovering
* an invalid snapshot.
*/
uint32_t valid;
/*
* Simple, incrementing version. no backward
* compatibility.
*/
uint32_t version;
/* In sectors */
uint32_t chunk_size;
};
struct disk_exception {
uint64_t old_chunk;
uint64_t new_chunk;
};
struct commit_callback {
void (*callback)(void *, int success);
void *context;
};
/*
* The top level structure for a persistent exception store.
*/
struct pstore {
struct dm_snapshot *snap; /* up pointer to my snapshot */
int version;
int valid;
uint32_t exceptions_per_area;
/*
* Now that we have an asynchronous kcopyd there is no
* need for large chunk sizes, so it wont hurt to have a
* whole chunks worth of metadata in memory at once.
*/
void *area;
/*
* An area of zeros used to clear the next area.
*/
void *zero_area;
/*
* Used to keep track of which metadata area the data in
* 'chunk' refers to.
*/
chunk_t current_area;
/*
* The next free chunk for an exception.
*/
chunk_t next_free;
/*
* The index of next free exception in the current
* metadata area.
*/
uint32_t current_committed;
atomic_t pending_count;
uint32_t callback_count;
struct commit_callback *callbacks;
struct dm_io_client *io_client;
struct workqueue_struct *metadata_wq;
};
static unsigned sectors_to_pages(unsigned sectors)
{
return DIV_ROUND_UP(sectors, PAGE_SIZE >> 9);
}
static int alloc_area(struct pstore *ps)
{
int r = -ENOMEM;
size_t len;
len = ps->snap->chunk_size << SECTOR_SHIFT;
/*
* Allocate the chunk_size block of memory that will hold
* a single metadata area.
*/
ps->area = vmalloc(len);
if (!ps->area)
return r;
ps->zero_area = vmalloc(len);
if (!ps->zero_area) {
vfree(ps->area);
return r;
}
memset(ps->zero_area, 0, len);
return 0;
}
static void free_area(struct pstore *ps)
{
vfree(ps->area);
ps->area = NULL;
vfree(ps->zero_area);
ps->zero_area = NULL;
}
struct mdata_req {
struct dm_io_region *where;
struct dm_io_request *io_req;
struct work_struct work;
int result;
};
static void do_metadata(struct work_struct *work)
{
struct mdata_req *req = container_of(work, struct mdata_req, work);
req->result = dm_io(req->io_req, 1, req->where, NULL);
}
/*
* Read or write a chunk aligned and sized block of data from a device.
*/
static int chunk_io(struct pstore *ps, chunk_t chunk, int rw, int metadata)
{
struct dm_io_region where = {
.bdev = ps->snap->cow->bdev,
.sector = ps->snap->chunk_size * chunk,
.count = ps->snap->chunk_size,
};
struct dm_io_request io_req = {
.bi_rw = rw,
.mem.type = DM_IO_VMA,
.mem.ptr.vma = ps->area,
.client = ps->io_client,
.notify.fn = NULL,
};
struct mdata_req req;
if (!metadata)
return dm_io(&io_req, 1, &where, NULL);
req.where = &where;
req.io_req = &io_req;
/*
* Issue the synchronous I/O from a different thread
* to avoid generic_make_request recursion.
*/
INIT_WORK(&req.work, do_metadata);
queue_work(ps->metadata_wq, &req.work);
flush_workqueue(ps->metadata_wq);
return req.result;
}
/*
* Convert a metadata area index to a chunk index.
*/
static chunk_t area_location(struct pstore *ps, chunk_t area)
{
return 1 + ((ps->exceptions_per_area + 1) * area);
}
/*
* Read or write a metadata area. Remembering to skip the first
* chunk which holds the header.
*/
static int area_io(struct pstore *ps, int rw)
{
int r;
chunk_t chunk;
chunk = area_location(ps, ps->current_area);
r = chunk_io(ps, chunk, rw, 0);
if (r)
return r;
return 0;
}
static void zero_memory_area(struct pstore *ps)
{
memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
}
static int zero_disk_area(struct pstore *ps, chunk_t area)
{
struct dm_io_region where = {
.bdev = ps->snap->cow->bdev,
.sector = ps->snap->chunk_size * area_location(ps, area),
.count = ps->snap->chunk_size,
};
struct dm_io_request io_req = {
.bi_rw = WRITE,
.mem.type = DM_IO_VMA,
.mem.ptr.vma = ps->zero_area,
.client = ps->io_client,
.notify.fn = NULL,
};
return dm_io(&io_req, 1, &where, NULL);
}
static int read_header(struct pstore *ps, int *new_snapshot)
{
int r;
struct disk_header *dh;
chunk_t chunk_size;
int chunk_size_supplied = 1;
/*
* Use default chunk size (or hardsect_size, if larger) if none supplied
*/
if (!ps->snap->chunk_size) {
ps->snap->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS,
bdev_hardsect_size(ps->snap->cow->bdev) >> 9);
ps->snap->chunk_mask = ps->snap->chunk_size - 1;
ps->snap->chunk_shift = ffs(ps->snap->chunk_size) - 1;
chunk_size_supplied = 0;
}
ps->io_client = dm_io_client_create(sectors_to_pages(ps->snap->
chunk_size));
if (IS_ERR(ps->io_client))
return PTR_ERR(ps->io_client);
r = alloc_area(ps);
if (r)
return r;
r = chunk_io(ps, 0, READ, 1);
if (r)
goto bad;
dh = (struct disk_header *) ps->area;
if (le32_to_cpu(dh->magic) == 0) {
*new_snapshot = 1;
return 0;
}
if (le32_to_cpu(dh->magic) != SNAP_MAGIC) {
DMWARN("Invalid or corrupt snapshot");
r = -ENXIO;
goto bad;
}
*new_snapshot = 0;
ps->valid = le32_to_cpu(dh->valid);
ps->version = le32_to_cpu(dh->version);
chunk_size = le32_to_cpu(dh->chunk_size);
if (!chunk_size_supplied || ps->snap->chunk_size == chunk_size)
return 0;
DMWARN("chunk size %llu in device metadata overrides "
"table chunk size of %llu.",
(unsigned long long)chunk_size,
(unsigned long long)ps->snap->chunk_size);
/* We had a bogus chunk_size. Fix stuff up. */
free_area(ps);
ps->snap->chunk_size = chunk_size;
ps->snap->chunk_mask = chunk_size - 1;
ps->snap->chunk_shift = ffs(chunk_size) - 1;
r = dm_io_client_resize(sectors_to_pages(ps->snap->chunk_size),
ps->io_client);
if (r)
return r;
r = alloc_area(ps);
return r;
bad:
free_area(ps);
return r;
}
static int write_header(struct pstore *ps)
{
struct disk_header *dh;
memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
dh = (struct disk_header *) ps->area;
dh->magic = cpu_to_le32(SNAP_MAGIC);
dh->valid = cpu_to_le32(ps->valid);
dh->version = cpu_to_le32(ps->version);
dh->chunk_size = cpu_to_le32(ps->snap->chunk_size);
return chunk_io(ps, 0, WRITE, 1);
}
/*
* Access functions for the disk exceptions, these do the endian conversions.
*/
static struct disk_exception *get_exception(struct pstore *ps, uint32_t index)
{
BUG_ON(index >= ps->exceptions_per_area);
return ((struct disk_exception *) ps->area) + index;
}
static void read_exception(struct pstore *ps,
uint32_t index, struct disk_exception *result)
{
struct disk_exception *e = get_exception(ps, index);
/* copy it */
result->old_chunk = le64_to_cpu(e->old_chunk);
result->new_chunk = le64_to_cpu(e->new_chunk);
}
static void write_exception(struct pstore *ps,
uint32_t index, struct disk_exception *de)
{
struct disk_exception *e = get_exception(ps, index);
/* copy it */
e->old_chunk = cpu_to_le64(de->old_chunk);
e->new_chunk = cpu_to_le64(de->new_chunk);
}
#define DM_MSG_PREFIX "snapshot exception stores"
/*
* Registers the exceptions that are present in the current area.
* 'full' is filled in to indicate if the area has been
* filled.
*/
static int insert_exceptions(struct pstore *ps, int *full)
int dm_exception_store_init(void)
{
int r;
unsigned int i;
struct disk_exception de;
/* presume the area is full */
*full = 1;
for (i = 0; i < ps->exceptions_per_area; i++) {
read_exception(ps, i, &de);
/*
* If the new_chunk is pointing at the start of
* the COW device, where the first metadata area
* is we know that we've hit the end of the
* exceptions. Therefore the area is not full.
*/
if (de.new_chunk == 0LL) {
ps->current_committed = i;
*full = 0;
break;
}
/*
* Keep track of the start of the free chunks.
*/
if (ps->next_free <= de.new_chunk)
ps->next_free = de.new_chunk + 1;
/*
* Otherwise we add the exception to the snapshot.
*/
r = dm_add_exception(ps->snap, de.old_chunk, de.new_chunk);
if (r)
return r;
}
return 0;
}
static int read_exceptions(struct pstore *ps)
{
int r, full = 1;
/*
* Keeping reading chunks and inserting exceptions until
* we find a partially full area.
*/
for (ps->current_area = 0; full; ps->current_area++) {
r = area_io(ps, READ);
if (r)
return r;
r = insert_exceptions(ps, &full);
if (r)
return r;
r = dm_transient_snapshot_init();
if (r) {
DMERR("Unable to register transient exception store type.");
goto transient_fail;
}
ps->current_area--;
return 0;
}
static struct pstore *get_info(struct exception_store *store)
{
return (struct pstore *) store->context;
}
static void persistent_fraction_full(struct exception_store *store,
sector_t *numerator, sector_t *denominator)
{
*numerator = get_info(store)->next_free * store->snap->chunk_size;
*denominator = get_dev_size(store->snap->cow->bdev);
}
static void persistent_destroy(struct exception_store *store)
{
struct pstore *ps = get_info(store);
destroy_workqueue(ps->metadata_wq);
dm_io_client_destroy(ps->io_client);
vfree(ps->callbacks);
free_area(ps);
kfree(ps);
}
static int persistent_read_metadata(struct exception_store *store)
{
int r, uninitialized_var(new_snapshot);
struct pstore *ps = get_info(store);
/*
* Read the snapshot header.
*/
r = read_header(ps, &new_snapshot);
if (r)
return r;
/*
* Now we know correct chunk_size, complete the initialisation.
*/
ps->exceptions_per_area = (ps->snap->chunk_size << SECTOR_SHIFT) /
sizeof(struct disk_exception);
ps->callbacks = dm_vcalloc(ps->exceptions_per_area,
sizeof(*ps->callbacks));
if (!ps->callbacks)
return -ENOMEM;
/*
* Do we need to setup a new snapshot ?
*/
if (new_snapshot) {
r = write_header(ps);
if (r) {
DMWARN("write_header failed");
return r;
}
ps->current_area = 0;
zero_memory_area(ps);
r = zero_disk_area(ps, 0);
if (r) {
DMWARN("zero_disk_area(0) failed");
return r;
}
} else {
/*
* Sanity checks.
*/
if (ps->version != SNAPSHOT_DISK_VERSION) {
DMWARN("unable to handle snapshot disk version %d",
ps->version);
return -EINVAL;
}
/*
* Metadata are valid, but snapshot is invalidated
*/
if (!ps->valid)
return 1;
/*
* Read the metadata.
*/
r = read_exceptions(ps);
if (r)
return r;
r = dm_persistent_snapshot_init();
if (r) {
DMERR("Unable to register persistent exception store type");
goto persistent_fail;
}
return 0;
}
static int persistent_prepare(struct exception_store *store,
struct dm_snap_exception *e)
{
struct pstore *ps = get_info(store);
uint32_t stride;
chunk_t next_free;
sector_t size = get_dev_size(store->snap->cow->bdev);
/* Is there enough room ? */
if (size < ((ps->next_free + 1) * store->snap->chunk_size))
return -ENOSPC;