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
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 1c61580..72880b7 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -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 \
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 3326750..35bda49 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1322,11 +1322,7 @@
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);
}
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index 848b381..59ee1b0 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -364,11 +364,7 @@
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);
}
diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index 01590f3e..dccbfb0 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -1,756 +1,45 @@
/*
- * 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 */
+#define DM_MSG_PREFIX "snapshot exception stores"
-/*-----------------------------------------------------------------
- * 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 dm_exception_store_init(void)
{
int r;
- chunk_t chunk;
- chunk = area_location(ps, ps->current_area);
+ r = dm_transient_snapshot_init();
+ if (r) {
+ DMERR("Unable to register transient exception store type.");
+ goto transient_fail;
+ }
- r = chunk_io(ps, chunk, rw, 0);
- 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 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);
+persistent_fail:
+ dm_persistent_snapshot_exit();
+transient_fail:
return r;
}
-static int write_header(struct pstore *ps)
+void dm_exception_store_exit(void)
{
- 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);
-}
-
-/*
- * 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 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;
- }
-
- 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;
- }
-
- 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;
-
- e->new_chunk = ps->next_free;
-
- /*
- * Move onto the next free pending, making sure to take
- * into account the location of the metadata chunks.
- */
- stride = (ps->exceptions_per_area + 1);
- next_free = ++ps->next_free;
- if (sector_div(next_free, stride) == 1)
- ps->next_free++;
-
- atomic_inc(&ps->pending_count);
- return 0;
-}
-
-static void persistent_commit(struct exception_store *store,
- struct dm_snap_exception *e,
- void (*callback) (void *, int success),
- void *callback_context)
-{
- unsigned int i;
- struct pstore *ps = get_info(store);
- struct disk_exception de;
- struct commit_callback *cb;
-
- de.old_chunk = e->old_chunk;
- de.new_chunk = e->new_chunk;
- write_exception(ps, ps->current_committed++, &de);
-
- /*
- * Add the callback to the back of the array. This code
- * is the only place where the callback array is
- * manipulated, and we know that it will never be called
- * multiple times concurrently.
- */
- cb = ps->callbacks + ps->callback_count++;
- cb->callback = callback;
- cb->context = callback_context;
-
- /*
- * If there are exceptions in flight and we have not yet
- * filled this metadata area there's nothing more to do.
- */
- if (!atomic_dec_and_test(&ps->pending_count) &&
- (ps->current_committed != ps->exceptions_per_area))
- return;
-
- /*
- * If we completely filled the current area, then wipe the next one.
- */
- if ((ps->current_committed == ps->exceptions_per_area) &&
- zero_disk_area(ps, ps->current_area + 1))
- ps->valid = 0;
-
- /*
- * Commit exceptions to disk.
- */
- if (ps->valid && area_io(ps, WRITE))
- ps->valid = 0;
-
- /*
- * Advance to the next area if this one is full.
- */
- if (ps->current_committed == ps->exceptions_per_area) {
- ps->current_committed = 0;
- ps->current_area++;
- zero_memory_area(ps);
- }
-
- for (i = 0; i < ps->callback_count; i++) {
- cb = ps->callbacks + i;
- cb->callback(cb->context, ps->valid);
- }
-
- ps->callback_count = 0;
-}
-
-static void persistent_drop(struct exception_store *store)
-{
- struct pstore *ps = get_info(store);
-
- ps->valid = 0;
- if (write_header(ps))
- DMWARN("write header failed");
-}
-
-int dm_create_persistent(struct exception_store *store)
-{
- struct pstore *ps;
-
- /* allocate the pstore */
- ps = kmalloc(sizeof(*ps), GFP_KERNEL);
- if (!ps)
- return -ENOMEM;
-
- ps->snap = store->snap;
- ps->valid = 1;
- ps->version = SNAPSHOT_DISK_VERSION;
- ps->area = NULL;
- ps->next_free = 2; /* skipping the header and first area */
- ps->current_committed = 0;
-
- ps->callback_count = 0;
- atomic_set(&ps->pending_count, 0);
- ps->callbacks = NULL;
-
- ps->metadata_wq = create_singlethread_workqueue("ksnaphd");
- if (!ps->metadata_wq) {
- kfree(ps);
- DMERR("couldn't start header metadata update thread");
- return -ENOMEM;
- }
-
- store->destroy = persistent_destroy;
- store->read_metadata = persistent_read_metadata;
- store->prepare_exception = persistent_prepare;
- store->commit_exception = persistent_commit;
- store->drop_snapshot = persistent_drop;
- store->fraction_full = persistent_fraction_full;
- store->context = ps;
-
- return 0;
-}
-
-/*-----------------------------------------------------------------
- * Implementation of the store for non-persistent snapshots.
- *---------------------------------------------------------------*/
-struct transient_c {
- sector_t next_free;
-};
-
-static void transient_destroy(struct exception_store *store)
-{
- kfree(store->context);
-}
-
-static int transient_read_metadata(struct exception_store *store)
-{
- return 0;
-}
-
-static int transient_prepare(struct exception_store *store,
- struct dm_snap_exception *e)
-{
- struct transient_c *tc = (struct transient_c *) store->context;
- sector_t size = get_dev_size(store->snap->cow->bdev);
-
- if (size < (tc->next_free + store->snap->chunk_size))
- return -1;
-
- e->new_chunk = sector_to_chunk(store->snap, tc->next_free);
- tc->next_free += store->snap->chunk_size;
-
- return 0;
-}
-
-static void transient_commit(struct exception_store *store,
- struct dm_snap_exception *e,
- void (*callback) (void *, int success),
- void *callback_context)
-{
- /* Just succeed */
- callback(callback_context, 1);
-}
-
-static void transient_fraction_full(struct exception_store *store,
- sector_t *numerator, sector_t *denominator)
-{
- *numerator = ((struct transient_c *) store->context)->next_free;
- *denominator = get_dev_size(store->snap->cow->bdev);
-}
-
-int dm_create_transient(struct exception_store *store)
-{
- struct transient_c *tc;
-
- store->destroy = transient_destroy;
- store->read_metadata = transient_read_metadata;
- store->prepare_exception = transient_prepare;
- store->commit_exception = transient_commit;
- store->drop_snapshot = NULL;
- store->fraction_full = transient_fraction_full;
-
- tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
- if (!tc)
- return -ENOMEM;
-
- tc->next_free = 0;
- store->context = tc;
-
- return 0;
+ dm_persistent_snapshot_exit();
+ dm_transient_snapshot_exit();
}
diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h
new file mode 100644
index 0000000..bb9f33d
--- /dev/null
+++ b/drivers/md/dm-exception-store.h
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
+ * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
+ *
+ * Device-mapper snapshot exception store.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef _LINUX_DM_EXCEPTION_STORE
+#define _LINUX_DM_EXCEPTION_STORE
+
+#include <linux/blkdev.h>
+#include <linux/device-mapper.h>
+
+/*
+ * The snapshot code deals with largish chunks of the disk at a
+ * time. Typically 32k - 512k.
+ */
+typedef sector_t chunk_t;
+
+/*
+ * An exception is used where an old chunk of data has been
+ * replaced by a new one.
+ * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
+ * of chunks that follow contiguously. Remaining bits hold the number of the
+ * chunk within the device.
+ */
+struct dm_snap_exception {
+ struct list_head hash_list;
+
+ chunk_t old_chunk;
+ chunk_t new_chunk;
+};
+
+/*
+ * Abstraction to handle the meta/layout of exception stores (the
+ * COW device).
+ */
+struct dm_exception_store {
+ /*
+ * Destroys this object when you've finished with it.
+ */
+ void (*destroy) (struct dm_exception_store *store);
+
+ /*
+ * The target shouldn't read the COW device until this is
+ * called. As exceptions are read from the COW, they are
+ * reported back via the callback.
+ */
+ int (*read_metadata) (struct dm_exception_store *store,
+ int (*callback)(void *callback_context,
+ chunk_t old, chunk_t new),
+ void *callback_context);
+
+ /*
+ * Find somewhere to store the next exception.
+ */
+ int (*prepare_exception) (struct dm_exception_store *store,
+ struct dm_snap_exception *e);
+
+ /*
+ * Update the metadata with this exception.
+ */
+ void (*commit_exception) (struct dm_exception_store *store,
+ struct dm_snap_exception *e,
+ void (*callback) (void *, int success),
+ void *callback_context);
+
+ /*
+ * The snapshot is invalid, note this in the metadata.
+ */
+ void (*drop_snapshot) (struct dm_exception_store *store);
+
+ int (*status) (struct dm_exception_store *store, status_type_t status,
+ char *result, unsigned int maxlen);
+
+ /*
+ * Return how full the snapshot is.
+ */
+ void (*fraction_full) (struct dm_exception_store *store,
+ sector_t *numerator,
+ sector_t *denominator);
+
+ struct dm_snapshot *snap;
+ void *context;
+};
+
+/*
+ * Funtions to manipulate consecutive chunks
+ */
+# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64)
+# define DM_CHUNK_CONSECUTIVE_BITS 8
+# define DM_CHUNK_NUMBER_BITS 56
+
+static inline chunk_t dm_chunk_number(chunk_t chunk)
+{
+ return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
+}
+
+static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
+{
+ return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
+{
+ e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
+
+ BUG_ON(!dm_consecutive_chunk_count(e));
+}
+
+# else
+# define DM_CHUNK_CONSECUTIVE_BITS 0
+
+static inline chunk_t dm_chunk_number(chunk_t chunk)
+{
+ return chunk;
+}
+
+static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
+{
+ return 0;
+}
+
+static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
+{
+}
+
+# endif
+
+int dm_exception_store_init(void);
+void dm_exception_store_exit(void);
+
+/*
+ * Two exception store implementations.
+ */
+int dm_persistent_snapshot_init(void);
+void dm_persistent_snapshot_exit(void);
+
+int dm_transient_snapshot_init(void);
+void dm_transient_snapshot_exit(void);
+
+int dm_create_persistent(struct dm_exception_store *store);
+
+int dm_create_transient(struct dm_exception_store *store);
+
+#endif /* _LINUX_DM_EXCEPTION_STORE */
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 777c948..54d0588 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -233,7 +233,7 @@
}
if (hc->new_map)
- dm_table_put(hc->new_map);
+ dm_table_destroy(hc->new_map);
dm_put(hc->md);
free_cell(hc);
}
@@ -827,8 +827,8 @@
r = dm_swap_table(md, new_map);
if (r) {
+ dm_table_destroy(new_map);
dm_put(md);
- dm_table_put(new_map);
return r;
}
@@ -836,8 +836,6 @@
set_disk_ro(dm_disk(md), 0);
else
set_disk_ro(dm_disk(md), 1);
-
- dm_table_put(new_map);
}
if (dm_suspended(md))
@@ -1080,7 +1078,7 @@
}
if (hc->new_map)
- dm_table_put(hc->new_map);
+ dm_table_destroy(hc->new_map);
hc->new_map = t;
up_write(&_hash_lock);
@@ -1109,7 +1107,7 @@
}
if (hc->new_map) {
- dm_table_put(hc->new_map);
+ dm_table_destroy(hc->new_map);
hc->new_map = NULL;
}
@@ -1550,8 +1548,10 @@
goto out;
}
- strcpy(name, hc->name);
- strcpy(uuid, hc->uuid ? : "");
+ if (name)
+ strcpy(name, hc->name);
+ if (uuid)
+ strcpy(uuid, hc->uuid ? : "");
out:
up_read(&_hash_lock);
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 44042be..bfa107f 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -142,6 +142,7 @@
.status = linear_status,
.ioctl = linear_ioctl,
.merge = linear_merge,
+ .features = DM_TARGET_SUPPORTS_BARRIERS,
};
int __init dm_linear_init(void)
@@ -156,8 +157,5 @@
void dm_linear_exit(void)
{
- int r = dm_unregister_target(&linear_target);
-
- if (r < 0)
- DMERR("unregister failed %d", r);
+ dm_unregister_target(&linear_target);
}
diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index a8c0fc7..737961f 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -326,8 +326,6 @@
static int rw_header(struct log_c *lc, int rw)
{
lc->io_req.bi_rw = rw;
- lc->io_req.mem.ptr.vma = lc->disk_header;
- lc->io_req.notify.fn = NULL;
return dm_io(&lc->io_req, 1, &lc->header_location, NULL);
}
@@ -362,10 +360,15 @@
return 0;
}
-static inline int write_header(struct log_c *log)
+static int _check_region_size(struct dm_target *ti, uint32_t region_size)
{
- header_to_disk(&log->header, log->disk_header);
- return rw_header(log, WRITE);
+ if (region_size < 2 || region_size > ti->len)
+ return 0;
+
+ if (!is_power_of_2(region_size))
+ return 0;
+
+ return 1;
}
/*----------------------------------------------------------------
@@ -403,8 +406,9 @@
}
}
- if (sscanf(argv[0], "%u", ®ion_size) != 1) {
- DMWARN("invalid region size string");
+ if (sscanf(argv[0], "%u", ®ion_size) != 1 ||
+ !_check_region_size(ti, region_size)) {
+ DMWARN("invalid region size %s", argv[0]);
return -EINVAL;
}
@@ -453,8 +457,18 @@
*/
buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) +
bitset_size, ti->limits.hardsect_size);
+
+ if (buf_size > dev->bdev->bd_inode->i_size) {
+ DMWARN("log device %s too small: need %llu bytes",
+ dev->name, (unsigned long long)buf_size);
+ kfree(lc);
+ return -EINVAL;
+ }
+
lc->header_location.count = buf_size >> SECTOR_SHIFT;
+
lc->io_req.mem.type = DM_IO_VMA;
+ lc->io_req.notify.fn = NULL;
lc->io_req.client = dm_io_client_create(dm_div_up(buf_size,
PAGE_SIZE));
if (IS_ERR(lc->io_req.client)) {
@@ -467,10 +481,12 @@
lc->disk_header = vmalloc(buf_size);
if (!lc->disk_header) {
DMWARN("couldn't allocate disk log buffer");
+ dm_io_client_destroy(lc->io_req.client);
kfree(lc);
return -ENOMEM;
}
+ lc->io_req.mem.ptr.vma = lc->disk_header;
lc->clean_bits = (void *)lc->disk_header +
(LOG_OFFSET << SECTOR_SHIFT);
}
@@ -482,6 +498,8 @@
DMWARN("couldn't allocate sync bitset");
if (!dev)
vfree(lc->clean_bits);
+ else
+ dm_io_client_destroy(lc->io_req.client);
vfree(lc->disk_header);
kfree(lc);
return -ENOMEM;
@@ -495,6 +513,8 @@
vfree(lc->sync_bits);
if (!dev)
vfree(lc->clean_bits);
+ else
+ dm_io_client_destroy(lc->io_req.client);
vfree(lc->disk_header);
kfree(lc);
return -ENOMEM;
@@ -631,8 +651,10 @@
/* set the correct number of regions in the header */
lc->header.nr_regions = lc->region_count;
+ header_to_disk(&lc->header, lc->disk_header);
+
/* write the new header */
- r = write_header(lc);
+ r = rw_header(lc, WRITE);
if (r) {
DMWARN("%s: Failed to write header on dirty region log device",
lc->log_dev->name);
@@ -682,7 +704,7 @@
if (!lc->touched)
return 0;
- r = write_header(lc);
+ r = rw_header(lc, WRITE);
if (r)
fail_log_device(lc);
else
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 3d7f492..095f77b 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -889,7 +889,7 @@
dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti,
pgpath->path.dev->name, m->nr_valid_paths);
- queue_work(kmultipathd, &m->trigger_event);
+ schedule_work(&m->trigger_event);
queue_work(kmultipathd, &pgpath->deactivate_path);
out:
@@ -932,7 +932,7 @@
dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti,
pgpath->path.dev->name, m->nr_valid_paths);
- queue_work(kmultipathd, &m->trigger_event);
+ schedule_work(&m->trigger_event);
out:
spin_unlock_irqrestore(&m->lock, flags);
@@ -976,7 +976,7 @@
spin_unlock_irqrestore(&m->lock, flags);
- queue_work(kmultipathd, &m->trigger_event);
+ schedule_work(&m->trigger_event);
}
/*
@@ -1006,7 +1006,7 @@
}
spin_unlock_irqrestore(&m->lock, flags);
- queue_work(kmultipathd, &m->trigger_event);
+ schedule_work(&m->trigger_event);
return 0;
}
@@ -1495,14 +1495,10 @@
static void __exit dm_multipath_exit(void)
{
- int r;
-
destroy_workqueue(kmpath_handlerd);
destroy_workqueue(kmultipathd);
- r = dm_unregister_target(&multipath_target);
- if (r < 0)
- DMERR("target unregister failed %d", r);
+ dm_unregister_target(&multipath_target);
kmem_cache_destroy(_mpio_cache);
}
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index ec43f9f..4d6bc10 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -197,9 +197,6 @@
struct mirror_set *ms = m->ms;
struct mirror *new;
- if (!errors_handled(ms))
- return;
-
/*
* error_count is used for nothing more than a
* simple way to tell if a device has encountered
@@ -210,6 +207,9 @@
if (test_and_set_bit(error_type, &m->error_type))
return;
+ if (!errors_handled(ms))
+ return;
+
if (m != get_default_mirror(ms))
goto out;
@@ -808,12 +808,6 @@
kfree(ms);
}
-static inline int _check_region_size(struct dm_target *ti, uint32_t size)
-{
- return !(size % (PAGE_SIZE >> 9) || !is_power_of_2(size) ||
- size > ti->len);
-}
-
static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
unsigned int mirror, char **argv)
{
@@ -872,12 +866,6 @@
return NULL;
}
- if (!_check_region_size(ti, dl->type->get_region_size(dl))) {
- ti->error = "Invalid region size";
- dm_dirty_log_destroy(dl);
- return NULL;
- }
-
return dl;
}
@@ -1300,11 +1288,7 @@
static void __exit dm_mirror_exit(void)
{
- int r;
-
- r = dm_unregister_target(&mirror_target);
- if (r < 0)
- DMERR("unregister failed %d", r);
+ dm_unregister_target(&mirror_target);
}
/* Module hooks */
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
new file mode 100644
index 0000000..936b34e
--- /dev/null
+++ b/drivers/md/dm-snap-persistent.c
@@ -0,0 +1,704 @@
+/*
+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
+ * Copyright (C) 2006-2008 Red Hat GmbH
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-exception-store.h"
+#include "dm-snap.h"
+
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/dm-io.h>
+
+#define DM_MSG_PREFIX "persistent snapshot"
+#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);
+}
+
+/*
+ * 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 (*callback)(void *callback_context,
+ chunk_t old, chunk_t new),
+ void *callback_context,
+ int *full)
+{
+ 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 = callback(callback_context, de.old_chunk, de.new_chunk);
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+static int read_exceptions(struct pstore *ps,
+ int (*callback)(void *callback_context, chunk_t old,
+ chunk_t new),
+ void *callback_context)
+{
+ 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, callback, callback_context, &full);
+ if (r)
+ return r;
+ }
+
+ ps->current_area--;
+
+ return 0;
+}
+
+static struct pstore *get_info(struct dm_exception_store *store)
+{
+ return (struct pstore *) store->context;
+}
+
+static void persistent_fraction_full(struct dm_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 dm_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 dm_exception_store *store,
+ int (*callback)(void *callback_context,
+ chunk_t old, chunk_t new),
+ void *callback_context)
+{
+ 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, callback, callback_context);
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+static int persistent_prepare_exception(struct dm_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;
+
+ e->new_chunk = ps->next_free;
+
+ /*
+ * Move onto the next free pending, making sure to take
+ * into account the location of the metadata chunks.
+ */
+ stride = (ps->exceptions_per_area + 1);
+ next_free = ++ps->next_free;
+ if (sector_div(next_free, stride) == 1)
+ ps->next_free++;
+
+ atomic_inc(&ps->pending_count);
+ return 0;
+}
+
+static void persistent_commit_exception(struct dm_exception_store *store,
+ struct dm_snap_exception *e,
+ void (*callback) (void *, int success),
+ void *callback_context)
+{
+ unsigned int i;
+ struct pstore *ps = get_info(store);
+ struct disk_exception de;
+ struct commit_callback *cb;
+
+ de.old_chunk = e->old_chunk;
+ de.new_chunk = e->new_chunk;
+ write_exception(ps, ps->current_committed++, &de);
+
+ /*
+ * Add the callback to the back of the array. This code
+ * is the only place where the callback array is
+ * manipulated, and we know that it will never be called
+ * multiple times concurrently.
+ */
+ cb = ps->callbacks + ps->callback_count++;
+ cb->callback = callback;
+ cb->context = callback_context;
+
+ /*
+ * If there are exceptions in flight and we have not yet
+ * filled this metadata area there's nothing more to do.
+ */
+ if (!atomic_dec_and_test(&ps->pending_count) &&
+ (ps->current_committed != ps->exceptions_per_area))
+ return;
+
+ /*
+ * If we completely filled the current area, then wipe the next one.
+ */
+ if ((ps->current_committed == ps->exceptions_per_area) &&
+ zero_disk_area(ps, ps->current_area + 1))
+ ps->valid = 0;
+
+ /*
+ * Commit exceptions to disk.
+ */
+ if (ps->valid && area_io(ps, WRITE))
+ ps->valid = 0;
+
+ /*
+ * Advance to the next area if this one is full.
+ */
+ if (ps->current_committed == ps->exceptions_per_area) {
+ ps->current_committed = 0;
+ ps->current_area++;
+ zero_memory_area(ps);
+ }
+
+ for (i = 0; i < ps->callback_count; i++) {
+ cb = ps->callbacks + i;
+ cb->callback(cb->context, ps->valid);
+ }
+
+ ps->callback_count = 0;
+}
+
+static void persistent_drop_snapshot(struct dm_exception_store *store)
+{
+ struct pstore *ps = get_info(store);
+
+ ps->valid = 0;
+ if (write_header(ps))
+ DMWARN("write header failed");
+}
+
+int dm_create_persistent(struct dm_exception_store *store)
+{
+ struct pstore *ps;
+
+ /* allocate the pstore */
+ ps = kmalloc(sizeof(*ps), GFP_KERNEL);
+ if (!ps)
+ return -ENOMEM;
+
+ ps->snap = store->snap;
+ ps->valid = 1;
+ ps->version = SNAPSHOT_DISK_VERSION;
+ ps->area = NULL;
+ ps->next_free = 2; /* skipping the header and first area */
+ ps->current_committed = 0;
+
+ ps->callback_count = 0;
+ atomic_set(&ps->pending_count, 0);
+ ps->callbacks = NULL;
+
+ ps->metadata_wq = create_singlethread_workqueue("ksnaphd");
+ if (!ps->metadata_wq) {
+ kfree(ps);
+ DMERR("couldn't start header metadata update thread");
+ return -ENOMEM;
+ }
+
+ store->destroy = persistent_destroy;
+ store->read_metadata = persistent_read_metadata;
+ store->prepare_exception = persistent_prepare_exception;
+ store->commit_exception = persistent_commit_exception;
+ store->drop_snapshot = persistent_drop_snapshot;
+ store->fraction_full = persistent_fraction_full;
+ store->context = ps;
+
+ return 0;
+}
+
+int dm_persistent_snapshot_init(void)
+{
+ return 0;
+}
+
+void dm_persistent_snapshot_exit(void)
+{
+}
diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c
new file mode 100644
index 0000000..7f6e2e6
--- /dev/null
+++ b/drivers/md/dm-snap-transient.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
+ * Copyright (C) 2006-2008 Red Hat GmbH
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-exception-store.h"
+#include "dm-snap.h"
+
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/dm-io.h>
+
+#define DM_MSG_PREFIX "transient snapshot"
+
+/*-----------------------------------------------------------------
+ * Implementation of the store for non-persistent snapshots.
+ *---------------------------------------------------------------*/
+struct transient_c {
+ sector_t next_free;
+};
+
+static void transient_destroy(struct dm_exception_store *store)
+{
+ kfree(store->context);
+}
+
+static int transient_read_metadata(struct dm_exception_store *store,
+ int (*callback)(void *callback_context,
+ chunk_t old, chunk_t new),
+ void *callback_context)
+{
+ return 0;
+}
+
+static int transient_prepare_exception(struct dm_exception_store *store,
+ struct dm_snap_exception *e)
+{
+ struct transient_c *tc = (struct transient_c *) store->context;
+ sector_t size = get_dev_size(store->snap->cow->bdev);
+
+ if (size < (tc->next_free + store->snap->chunk_size))
+ return -1;
+
+ e->new_chunk = sector_to_chunk(store->snap, tc->next_free);
+ tc->next_free += store->snap->chunk_size;
+
+ return 0;
+}
+
+static void transient_commit_exception(struct dm_exception_store *store,
+ struct dm_snap_exception *e,
+ void (*callback) (void *, int success),
+ void *callback_context)
+{
+ /* Just succeed */
+ callback(callback_context, 1);
+}
+
+static void transient_fraction_full(struct dm_exception_store *store,
+ sector_t *numerator, sector_t *denominator)
+{
+ *numerator = ((struct transient_c *) store->context)->next_free;
+ *denominator = get_dev_size(store->snap->cow->bdev);
+}
+
+int dm_create_transient(struct dm_exception_store *store)
+{
+ struct transient_c *tc;
+
+ store->destroy = transient_destroy;
+ store->read_metadata = transient_read_metadata;
+ store->prepare_exception = transient_prepare_exception;
+ store->commit_exception = transient_commit_exception;
+ store->drop_snapshot = NULL;
+ store->fraction_full = transient_fraction_full;
+
+ tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
+ if (!tc)
+ return -ENOMEM;
+
+ tc->next_free = 0;
+ store->context = tc;
+
+ return 0;
+}
+
+int dm_transient_snapshot_init(void)
+{
+ return 0;
+}
+
+void dm_transient_snapshot_exit(void)
+{
+}
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 6c96db2..65ff82f 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -9,6 +9,7 @@
#include <linux/blkdev.h>
#include <linux/ctype.h>
#include <linux/device-mapper.h>
+#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kdev_t.h>
@@ -20,6 +21,7 @@
#include <linux/log2.h>
#include <linux/dm-kcopyd.h>
+#include "dm-exception-store.h"
#include "dm-snap.h"
#include "dm-bio-list.h"
@@ -428,8 +430,13 @@
list_add(&new_e->hash_list, e ? &e->hash_list : l);
}
-int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new)
+/*
+ * Callback used by the exception stores to load exceptions when
+ * initialising.
+ */
+static int dm_add_exception(void *context, chunk_t old, chunk_t new)
{
+ struct dm_snapshot *s = context;
struct dm_snap_exception *e;
e = alloc_exception();
@@ -658,7 +665,7 @@
spin_lock_init(&s->tracked_chunk_lock);
/* Metadata must only be loaded into one table at once */
- r = s->store.read_metadata(&s->store);
+ r = s->store.read_metadata(&s->store, dm_add_exception, (void *)s);
if (r < 0) {
ti->error = "Failed to read snapshot metadata";
goto bad_load_and_register;
@@ -735,7 +742,7 @@
unregister_snapshot(s);
while (atomic_read(&s->pending_exceptions_count))
- yield();
+ msleep(1);
/*
* Ensure instructions in mempool_destroy aren't reordered
* before atomic_read.
@@ -888,10 +895,10 @@
/*
* Check for conflicting reads. This is extremely improbable,
- * so yield() is sufficient and there is no need for a wait queue.
+ * so msleep(1) is sufficient and there is no need for a wait queue.
*/
while (__chunk_is_tracked(s, pe->e.old_chunk))
- yield();
+ msleep(1);
/*
* Add a proper exception, and remove the
@@ -1404,6 +1411,12 @@
{
int r;
+ r = dm_exception_store_init();
+ if (r) {
+ DMERR("Failed to initialize exception stores");
+ return r;
+ }
+
r = dm_register_target(&snapshot_target);
if (r) {
DMERR("snapshot target register failed %d", r);
@@ -1452,39 +1465,34 @@
return 0;
- bad_pending_pool:
+bad_pending_pool:
kmem_cache_destroy(tracked_chunk_cache);
- bad5:
+bad5:
kmem_cache_destroy(pending_cache);
- bad4:
+bad4:
kmem_cache_destroy(exception_cache);
- bad3:
+bad3:
exit_origin_hash();
- bad2:
+bad2:
dm_unregister_target(&origin_target);
- bad1:
+bad1:
dm_unregister_target(&snapshot_target);
return r;
}
static void __exit dm_snapshot_exit(void)
{
- int r;
-
destroy_workqueue(ksnapd);
- r = dm_unregister_target(&snapshot_target);
- if (r)
- DMERR("snapshot unregister failed %d", r);
-
- r = dm_unregister_target(&origin_target);
- if (r)
- DMERR("origin unregister failed %d", r);
+ dm_unregister_target(&snapshot_target);
+ dm_unregister_target(&origin_target);
exit_origin_hash();
kmem_cache_destroy(pending_cache);
kmem_cache_destroy(exception_cache);
kmem_cache_destroy(tracked_chunk_cache);
+
+ dm_exception_store_exit();
}
/* Module hooks */
diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h
index 99c0106..d9e62b4 100644
--- a/drivers/md/dm-snap.h
+++ b/drivers/md/dm-snap.h
@@ -1,6 +1,4 @@
/*
- * dm-snapshot.c
- *
* Copyright (C) 2001-2002 Sistina Software (UK) Limited.
*
* This file is released under the GPL.
@@ -10,6 +8,7 @@
#define DM_SNAPSHOT_H
#include <linux/device-mapper.h>
+#include "dm-exception-store.h"
#include "dm-bio-list.h"
#include <linux/blkdev.h>
#include <linux/workqueue.h>
@@ -20,116 +19,6 @@
struct list_head *table;
};
-/*
- * The snapshot code deals with largish chunks of the disk at a
- * time. Typically 32k - 512k.
- */
-typedef sector_t chunk_t;
-
-/*
- * An exception is used where an old chunk of data has been
- * replaced by a new one.
- * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
- * of chunks that follow contiguously. Remaining bits hold the number of the
- * chunk within the device.
- */
-struct dm_snap_exception {
- struct list_head hash_list;
-
- chunk_t old_chunk;
- chunk_t new_chunk;
-};
-
-/*
- * Funtions to manipulate consecutive chunks
- */
-# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64)
-# define DM_CHUNK_CONSECUTIVE_BITS 8
-# define DM_CHUNK_NUMBER_BITS 56
-
-static inline chunk_t dm_chunk_number(chunk_t chunk)
-{
- return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
-}
-
-static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
-{
- return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
-}
-
-static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
-{
- e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
-
- BUG_ON(!dm_consecutive_chunk_count(e));
-}
-
-# else
-# define DM_CHUNK_CONSECUTIVE_BITS 0
-
-static inline chunk_t dm_chunk_number(chunk_t chunk)
-{
- return chunk;
-}
-
-static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e)
-{
- return 0;
-}
-
-static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e)
-{
-}
-
-# endif
-
-/*
- * Abstraction to handle the meta/layout of exception stores (the
- * COW device).
- */
-struct exception_store {
-
- /*
- * Destroys this object when you've finished with it.
- */
- void (*destroy) (struct exception_store *store);
-
- /*
- * The target shouldn't read the COW device until this is
- * called.
- */
- int (*read_metadata) (struct exception_store *store);
-
- /*
- * Find somewhere to store the next exception.
- */
- int (*prepare_exception) (struct exception_store *store,
- struct dm_snap_exception *e);
-
- /*
- * Update the metadata with this exception.
- */
- void (*commit_exception) (struct exception_store *store,
- struct dm_snap_exception *e,
- void (*callback) (void *, int success),
- void *callback_context);
-
- /*
- * The snapshot is invalid, note this in the metadata.
- */
- void (*drop_snapshot) (struct exception_store *store);
-
- /*
- * Return how full the snapshot is.
- */
- void (*fraction_full) (struct exception_store *store,
- sector_t *numerator,
- sector_t *denominator);
-
- struct dm_snapshot *snap;
- void *context;
-};
-
#define DM_TRACKED_CHUNK_HASH_SIZE 16
#define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \
(DM_TRACKED_CHUNK_HASH_SIZE - 1))
@@ -172,7 +61,7 @@
spinlock_t pe_lock;
/* The on disk metadata handler */
- struct exception_store store;
+ struct dm_exception_store store;
struct dm_kcopyd_client *kcopyd_client;
@@ -187,20 +76,6 @@
};
/*
- * Used by the exception stores to load exceptions hen
- * initialising.
- */
-int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new);
-
-/*
- * Constructor and destructor for the default persistent
- * store.
- */
-int dm_create_persistent(struct exception_store *store);
-
-int dm_create_transient(struct exception_store *store);
-
-/*
* Return the number of sectors in the device.
*/
static inline sector_t get_dev_size(struct block_device *bdev)
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index 9e4ef88..41569bc 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -337,9 +337,7 @@
void dm_stripe_exit(void)
{
- if (dm_unregister_target(&stripe_target))
- DMWARN("target unregistration failed");
-
+ dm_unregister_target(&stripe_target);
destroy_workqueue(kstriped);
return;
diff --git a/drivers/md/dm-sysfs.c b/drivers/md/dm-sysfs.c
new file mode 100644
index 0000000..a2a45e6
--- /dev/null
+++ b/drivers/md/dm-sysfs.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/sysfs.h>
+#include <linux/dm-ioctl.h>
+#include "dm.h"
+
+struct dm_sysfs_attr {
+ struct attribute attr;
+ ssize_t (*show)(struct mapped_device *, char *);
+ ssize_t (*store)(struct mapped_device *, char *);
+};
+
+#define DM_ATTR_RO(_name) \
+struct dm_sysfs_attr dm_attr_##_name = \
+ __ATTR(_name, S_IRUGO, dm_attr_##_name##_show, NULL)
+
+static ssize_t dm_attr_show(struct kobject *kobj, struct attribute *attr,
+ char *page)
+{
+ struct dm_sysfs_attr *dm_attr;
+ struct mapped_device *md;
+ ssize_t ret;
+
+ dm_attr = container_of(attr, struct dm_sysfs_attr, attr);
+ if (!dm_attr->show)
+ return -EIO;
+
+ md = dm_get_from_kobject(kobj);
+ if (!md)
+ return -EINVAL;
+
+ ret = dm_attr->show(md, page);
+ dm_put(md);
+
+ return ret;
+}
+
+static ssize_t dm_attr_name_show(struct mapped_device *md, char *buf)
+{
+ if (dm_copy_name_and_uuid(md, buf, NULL))
+ return -EIO;
+
+ strcat(buf, "\n");
+ return strlen(buf);
+}
+
+static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf)
+{
+ if (dm_copy_name_and_uuid(md, NULL, buf))
+ return -EIO;
+
+ strcat(buf, "\n");
+ return strlen(buf);
+}
+
+static DM_ATTR_RO(name);
+static DM_ATTR_RO(uuid);
+
+static struct attribute *dm_attrs[] = {
+ &dm_attr_name.attr,
+ &dm_attr_uuid.attr,
+ NULL,
+};
+
+static struct sysfs_ops dm_sysfs_ops = {
+ .show = dm_attr_show,
+};
+
+/*
+ * dm kobject is embedded in mapped_device structure
+ * no need to define release function here
+ */
+static struct kobj_type dm_ktype = {
+ .sysfs_ops = &dm_sysfs_ops,
+ .default_attrs = dm_attrs,
+};
+
+/*
+ * Initialize kobj
+ * because nobody using md yet, no need to call explicit dm_get/put
+ */
+int dm_sysfs_init(struct mapped_device *md)
+{
+ return kobject_init_and_add(dm_kobject(md), &dm_ktype,
+ &disk_to_dev(dm_disk(md))->kobj,
+ "%s", "dm");
+}
+
+/*
+ * Remove kobj, called after all references removed
+ */
+void dm_sysfs_exit(struct mapped_device *md)
+{
+ kobject_put(dm_kobject(md));
+}
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 04e5fd7..2fd66c3 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1,6 +1,6 @@
/*
* Copyright (C) 2001 Sistina Software (UK) Limited.
- * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
@@ -15,6 +15,7 @@
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
+#include <linux/delay.h>
#include <asm/atomic.h>
#define DM_MSG_PREFIX "table"
@@ -24,6 +25,19 @@
#define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
#define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
+/*
+ * The table has always exactly one reference from either mapped_device->map
+ * or hash_cell->new_map. This reference is not counted in table->holders.
+ * A pair of dm_create_table/dm_destroy_table functions is used for table
+ * creation/destruction.
+ *
+ * Temporary references from the other code increase table->holders. A pair
+ * of dm_table_get/dm_table_put functions is used to manipulate it.
+ *
+ * When the table is about to be destroyed, we wait for table->holders to
+ * drop to zero.
+ */
+
struct dm_table {
struct mapped_device *md;
atomic_t holders;
@@ -38,6 +52,8 @@
sector_t *highs;
struct dm_target *targets;
+ unsigned barriers_supported:1;
+
/*
* Indicates the rw permissions for the new logical
* device. This should be a combination of FMODE_READ
@@ -226,7 +242,8 @@
return -ENOMEM;
INIT_LIST_HEAD(&t->devices);
- atomic_set(&t->holders, 1);
+ atomic_set(&t->holders, 0);
+ t->barriers_supported = 1;
if (!num_targets)
num_targets = KEYS_PER_NODE;
@@ -256,10 +273,14 @@
}
}
-static void table_destroy(struct dm_table *t)
+void dm_table_destroy(struct dm_table *t)
{
unsigned int i;
+ while (atomic_read(&t->holders))
+ msleep(1);
+ smp_mb();
+
/* free the indexes (see dm_table_complete) */
if (t->depth >= 2)
vfree(t->index[t->depth - 2]);
@@ -297,8 +318,8 @@
if (!t)
return;
- if (atomic_dec_and_test(&t->holders))
- table_destroy(t);
+ smp_mb__before_atomic_dec();
+ atomic_dec(&t->holders);
}
/*
@@ -728,6 +749,10 @@
/* FIXME: the plan is to combine high here and then have
* the merge fn apply the target level restrictions. */
combine_restrictions_low(&t->limits, &tgt->limits);
+
+ if (!(tgt->type->features & DM_TARGET_SUPPORTS_BARRIERS))
+ t->barriers_supported = 0;
+
return 0;
bad:
@@ -772,6 +797,12 @@
check_for_valid_limits(&t->limits);
+ /*
+ * We only support barriers if there is exactly one underlying device.
+ */
+ if (!list_is_singular(&t->devices))
+ t->barriers_supported = 0;
+
/* how many indexes will the btree have ? */
leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
@@ -986,6 +1017,12 @@
return t->md;
}
+int dm_table_barrier_ok(struct dm_table *t)
+{
+ return t->barriers_supported;
+}
+EXPORT_SYMBOL(dm_table_barrier_ok);
+
EXPORT_SYMBOL(dm_vcalloc);
EXPORT_SYMBOL(dm_get_device);
EXPORT_SYMBOL(dm_put_device);
diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c
index 835cf95..7decf10 100644
--- a/drivers/md/dm-target.c
+++ b/drivers/md/dm-target.c
@@ -130,26 +130,26 @@
return rv;
}
-int dm_unregister_target(struct target_type *t)
+void dm_unregister_target(struct target_type *t)
{
struct tt_internal *ti;
down_write(&_lock);
if (!(ti = __find_target_type(t->name))) {
- up_write(&_lock);
- return -EINVAL;
+ DMCRIT("Unregistering unrecognised target: %s", t->name);
+ BUG();
}
if (ti->use) {
- up_write(&_lock);
- return -ETXTBSY;
+ DMCRIT("Attempt to unregister target still in use: %s",
+ t->name);
+ BUG();
}
list_del(&ti->list);
kfree(ti);
up_write(&_lock);
- return 0;
}
/*
@@ -187,8 +187,7 @@
void dm_target_exit(void)
{
- if (dm_unregister_target(&error_target))
- DMWARN("error target unregistration failed");
+ dm_unregister_target(&error_target);
}
EXPORT_SYMBOL(dm_register_target);
diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c
index cdbf126..bbc9703 100644
--- a/drivers/md/dm-zero.c
+++ b/drivers/md/dm-zero.c
@@ -69,10 +69,7 @@
static void __exit dm_zero_exit(void)
{
- int r = dm_unregister_target(&zero_target);
-
- if (r < 0)
- DMERR("unregister failed %d", r);
+ dm_unregister_target(&zero_target);
}
module_init(dm_zero_init)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 421c9f0..51ba1db 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1,6 +1,6 @@
/*
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
- * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
@@ -32,6 +32,7 @@
static DEFINE_SPINLOCK(_minor_lock);
/*
+ * For bio-based dm.
* One of these is allocated per bio.
*/
struct dm_io {
@@ -43,6 +44,7 @@
};
/*
+ * For bio-based dm.
* One of these is allocated per target within a bio. Hopefully
* this will be simplified out one day.
*/
@@ -54,6 +56,27 @@
DEFINE_TRACE(block_bio_complete);
+/*
+ * For request-based dm.
+ * One of these is allocated per request.
+ */
+struct dm_rq_target_io {
+ struct mapped_device *md;
+ struct dm_target *ti;
+ struct request *orig, clone;
+ int error;
+ union map_info info;
+};
+
+/*
+ * For request-based dm.
+ * One of these is allocated per bio.
+ */
+struct dm_rq_clone_bio_info {
+ struct bio *orig;
+ struct request *rq;
+};
+
union map_info *dm_get_mapinfo(struct bio *bio)
{
if (bio && bio->bi_private)
@@ -144,11 +167,16 @@
/* forced geometry settings */
struct hd_geometry geometry;
+
+ /* sysfs handle */
+ struct kobject kobj;
};
#define MIN_IOS 256
static struct kmem_cache *_io_cache;
static struct kmem_cache *_tio_cache;
+static struct kmem_cache *_rq_tio_cache;
+static struct kmem_cache *_rq_bio_info_cache;
static int __init local_init(void)
{
@@ -164,9 +192,17 @@
if (!_tio_cache)
goto out_free_io_cache;
+ _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
+ if (!_rq_tio_cache)
+ goto out_free_tio_cache;
+
+ _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
+ if (!_rq_bio_info_cache)
+ goto out_free_rq_tio_cache;
+
r = dm_uevent_init();
if (r)
- goto out_free_tio_cache;
+ goto out_free_rq_bio_info_cache;
_major = major;
r = register_blkdev(_major, _name);
@@ -180,6 +216,10 @@
out_uevent_exit:
dm_uevent_exit();
+out_free_rq_bio_info_cache:
+ kmem_cache_destroy(_rq_bio_info_cache);
+out_free_rq_tio_cache:
+ kmem_cache_destroy(_rq_tio_cache);
out_free_tio_cache:
kmem_cache_destroy(_tio_cache);
out_free_io_cache:
@@ -190,6 +230,8 @@
static void local_exit(void)
{
+ kmem_cache_destroy(_rq_bio_info_cache);
+ kmem_cache_destroy(_rq_tio_cache);
kmem_cache_destroy(_tio_cache);
kmem_cache_destroy(_io_cache);
unregister_blkdev(_major, _name);
@@ -796,7 +838,11 @@
ci.map = dm_get_table(md);
if (unlikely(!ci.map))
return -EIO;
-
+ if (unlikely(bio_barrier(bio) && !dm_table_barrier_ok(ci.map))) {
+ dm_table_put(ci.map);
+ bio_endio(bio, -EOPNOTSUPP);
+ return 0;
+ }
ci.md = md;
ci.bio = bio;
ci.io = alloc_io(md);
@@ -880,15 +926,6 @@
struct mapped_device *md = q->queuedata;
int cpu;
- /*
- * There is no use in forwarding any barrier request since we can't
- * guarantee it is (or can be) handled by the targets correctly.
- */
- if (unlikely(bio_barrier(bio))) {
- bio_endio(bio, -EOPNOTSUPP);
- return 0;
- }
-
down_read(&md->io_lock);
cpu = part_stat_lock();
@@ -943,8 +980,6 @@
struct mapped_device *md = congested_data;
struct dm_table *map;
- atomic_inc(&md->pending);
-
if (!test_bit(DMF_BLOCK_IO, &md->flags)) {
map = dm_get_table(md);
if (map) {
@@ -953,10 +988,6 @@
}
}
- if (!atomic_dec_return(&md->pending))
- /* nudge anyone waiting on suspend queue */
- wake_up(&md->wait);
-
return r;
}
@@ -1216,10 +1247,12 @@
if (md->suspended_bdev)
__set_size(md, size);
- if (size == 0)
- return 0;
- dm_table_get(t);
+ if (!size) {
+ dm_table_destroy(t);
+ return 0;
+ }
+
dm_table_event_callback(t, event_callback, md);
write_lock(&md->map_lock);
@@ -1241,7 +1274,7 @@
write_lock(&md->map_lock);
md->map = NULL;
write_unlock(&md->map_lock);
- dm_table_put(map);
+ dm_table_destroy(map);
}
/*
@@ -1255,6 +1288,8 @@
if (!md)
return -ENXIO;
+ dm_sysfs_init(md);
+
*result = md;
return 0;
}
@@ -1330,8 +1365,9 @@
dm_table_presuspend_targets(map);
dm_table_postsuspend_targets(map);
}
- __unbind(md);
+ dm_sysfs_exit(md);
dm_table_put(map);
+ __unbind(md);
free_dev(md);
}
}
@@ -1669,6 +1705,27 @@
return md->disk;
}
+struct kobject *dm_kobject(struct mapped_device *md)
+{
+ return &md->kobj;
+}
+
+/*
+ * struct mapped_device should not be exported outside of dm.c
+ * so use this check to verify that kobj is part of md structure
+ */
+struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
+{
+ struct mapped_device *md;
+
+ md = container_of(kobj, struct mapped_device, kobj);
+ if (&md->kobj != kobj)
+ return NULL;
+
+ dm_get(md);
+ return md;
+}
+
int dm_suspended(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED, &md->flags);
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 0ade60c..20194e0 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -36,6 +36,7 @@
/*-----------------------------------------------------------------
* Internal table functions.
*---------------------------------------------------------------*/
+void dm_table_destroy(struct dm_table *t);
void dm_table_event_callback(struct dm_table *t,
void (*fn)(void *), void *context);
struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index);
@@ -51,6 +52,7 @@
* To check the return value from dm_table_find_target().
*/
#define dm_target_is_valid(t) ((t)->table)
+int dm_table_barrier_ok(struct dm_table *t);
/*-----------------------------------------------------------------
* A registry of target types.
@@ -72,6 +74,14 @@
void dm_interface_exit(void);
/*
+ * sysfs interface
+ */
+int dm_sysfs_init(struct mapped_device *md);
+void dm_sysfs_exit(struct mapped_device *md);
+struct kobject *dm_kobject(struct mapped_device *md);
+struct mapped_device *dm_get_from_kobject(struct kobject *kobj);
+
+/*
* Targets for linear and striped mappings
*/
int dm_linear_init(void);
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index c17fd33..8209e08 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -45,6 +45,8 @@
*/
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
union map_info *map_context);
+typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
+ union map_info *map_context);
/*
* Returns:
@@ -57,6 +59,9 @@
typedef int (*dm_endio_fn) (struct dm_target *ti,
struct bio *bio, int error,
union map_info *map_context);
+typedef int (*dm_request_endio_fn) (struct dm_target *ti,
+ struct request *clone, int error,
+ union map_info *map_context);
typedef void (*dm_flush_fn) (struct dm_target *ti);
typedef void (*dm_presuspend_fn) (struct dm_target *ti);
@@ -75,6 +80,13 @@
typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
struct bio_vec *biovec, int max_size);
+/*
+ * Returns:
+ * 0: The target can handle the next I/O immediately.
+ * 1: The target can't handle the next I/O immediately.
+ */
+typedef int (*dm_busy_fn) (struct dm_target *ti);
+
void dm_error(const char *message);
/*
@@ -100,14 +112,23 @@
/*
* Information about a target type
*/
+
+/*
+ * Target features
+ */
+#define DM_TARGET_SUPPORTS_BARRIERS 0x00000001
+
struct target_type {
+ uint64_t features;
const char *name;
struct module *module;
unsigned version[3];
dm_ctr_fn ctr;
dm_dtr_fn dtr;
dm_map_fn map;
+ dm_map_request_fn map_rq;
dm_endio_fn end_io;
+ dm_request_endio_fn rq_end_io;
dm_flush_fn flush;
dm_presuspend_fn presuspend;
dm_postsuspend_fn postsuspend;
@@ -117,6 +138,7 @@
dm_message_fn message;
dm_ioctl_fn ioctl;
dm_merge_fn merge;
+ dm_busy_fn busy;
};
struct io_restrictions {
@@ -157,8 +179,7 @@
};
int dm_register_target(struct target_type *t);
-int dm_unregister_target(struct target_type *t);
-
+void dm_unregister_target(struct target_type *t);
/*-----------------------------------------------------------------
* Functions for creating and manipulating mapped devices.
@@ -276,6 +297,9 @@
*---------------------------------------------------------------*/
#define DM_NAME "device-mapper"
+#define DMCRIT(f, arg...) \
+ printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
+
#define DMERR(f, arg...) \
printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
#define DMERR_LIMIT(f, arg...) \
