projects/linux·commit 79c63eeb

Merge tag 'dm-3.7-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm

79c63eeb · Linus Torvalds <[email protected]> · 2012-10-13 10:57:57 +09:00

Pull device-mapper changes from Alasdair G Kergon:
 "Remove the power-of-2 block size constraint on discards in dm thin
  provisioning and factor the bio_prison code out into a separate module
  (for sharing with the forthcoming cache target).

  Use struct bio's front_pad to eliminate the use of one separate
  mempool by bio-based devices.

  A few other tiny clean-ups."

* tag 'dm-3.7-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
  dm: store dm_target_io in bio front_pad
  dm thin: move bio_prison code to separate module
  dm thin: prepare to separate bio_prison code
  dm thin: support discard with non power of two block size
  dm persistent data: convert to use le32_add_cpu
  dm: use ACCESS_ONCE for sysfs values
  dm bufio: use list_move
  dm mpath: fix check for null mpio in end_io fn
Commit
79c63eeb805d086f52e5efda9c8d321beeed0b2b
Parents
6a5a3d6a · dba14160

Merge commit. Changes below are compared with the first parent: 6a5a3d6a.

Changes

10 files changed · +636 −511

FileStatusAddDelContent
drivers/md/Kconfigmodified+8−0View file
drivers/md/Makefilemodified+1−0View file
drivers/md/dm-bio-prison.cadded+415−0View file
drivers/md/dm-bio-prison.hadded+72−0View file
drivers/md/dm-bufio.cmodified+4−9View file
drivers/md/dm-mpath.cmodified+2−1View file
drivers/md/dm-thin.cmodified+82−439View file
drivers/md/dm-verity.cmodified+1−1View file
drivers/md/dm.cmodified+49−59View file
drivers/md/persistent-data/dm-space-map-common.cmodified+2−2View file

Only the first 600 diff lines are shown. Download the complete patch.

drivers/md/Kconfig

View file
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index d949b78..91a02ee 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -216,6 +216,13 @@ config DM_BUFIO
as a cache, holding recently-read blocks in memory and performing
delayed writes.
+config DM_BIO_PRISON
+ tristate
+ depends on BLK_DEV_DM && EXPERIMENTAL
+ ---help---
+ Some bio locking schemes used by other device-mapper targets
+ including thin provisioning.
+
source "drivers/md/persistent-data/Kconfig"
config DM_CRYPT
@@ -247,6 +254,7 @@ config DM_THIN_PROVISIONING
tristate "Thin provisioning target (EXPERIMENTAL)"
depends on BLK_DEV_DM && EXPERIMENTAL
select DM_PERSISTENT_DATA
+ select DM_BIO_PRISON
---help---
Provides thin provisioning and snapshots that share a data store.

drivers/md/Makefile

View file
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index 8b2e0df..94dce8b 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_MD_FAULTY) += faulty.o
obj-$(CONFIG_BLK_DEV_MD) += md-mod.o
obj-$(CONFIG_BLK_DEV_DM) += dm-mod.o
obj-$(CONFIG_DM_BUFIO) += dm-bufio.o
+obj-$(CONFIG_DM_BIO_PRISON) += dm-bio-prison.o
obj-$(CONFIG_DM_CRYPT) += dm-crypt.o
obj-$(CONFIG_DM_DELAY) += dm-delay.o
obj-$(CONFIG_DM_FLAKEY) += dm-flakey.o

drivers/md/dm-bio-prison.c

View file
diff --git a/drivers/md/dm-bio-prison.c b/drivers/md/dm-bio-prison.c
new file mode 100644
index 0000000..e4e8415
--- /dev/null
+++ b/drivers/md/dm-bio-prison.c
@@ -0,0 +1,415 @@
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+#include "dm-bio-prison.h"
+
+#include <linux/spinlock.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+/*----------------------------------------------------------------*/
+
+struct dm_bio_prison_cell {
+ struct hlist_node list;
+ struct dm_bio_prison *prison;
+ struct dm_cell_key key;
+ struct bio *holder;
+ struct bio_list bios;
+};
+
+struct dm_bio_prison {
+ spinlock_t lock;
+ mempool_t *cell_pool;
+
+ unsigned nr_buckets;
+ unsigned hash_mask;
+ struct hlist_head *cells;
+};
+
+/*----------------------------------------------------------------*/
+
+static uint32_t calc_nr_buckets(unsigned nr_cells)
+{
+ uint32_t n = 128;
+
+ nr_cells /= 4;
+ nr_cells = min(nr_cells, 8192u);
+
+ while (n < nr_cells)
+ n <<= 1;
+
+ return n;
+}
+
+static struct kmem_cache *_cell_cache;
+
+/*
+ * @nr_cells should be the number of cells you want in use _concurrently_.
+ * Don't confuse it with the number of distinct keys.
+ */
+struct dm_bio_prison *dm_bio_prison_create(unsigned nr_cells)
+{
+ unsigned i;
+ uint32_t nr_buckets = calc_nr_buckets(nr_cells);
+ size_t len = sizeof(struct dm_bio_prison) +
+ (sizeof(struct hlist_head) * nr_buckets);
+ struct dm_bio_prison *prison = kmalloc(len, GFP_KERNEL);
+
+ if (!prison)
+ return NULL;
+
+ spin_lock_init(&prison->lock);
+ prison->cell_pool = mempool_create_slab_pool(nr_cells, _cell_cache);
+ if (!prison->cell_pool) {
+ kfree(prison);
+ return NULL;
+ }
+
+ prison->nr_buckets = nr_buckets;
+ prison->hash_mask = nr_buckets - 1;
+ prison->cells = (struct hlist_head *) (prison + 1);
+ for (i = 0; i < nr_buckets; i++)
+ INIT_HLIST_HEAD(prison->cells + i);
+
+ return prison;
+}
+EXPORT_SYMBOL_GPL(dm_bio_prison_create);
+
+void dm_bio_prison_destroy(struct dm_bio_prison *prison)
+{
+ mempool_destroy(prison->cell_pool);
+ kfree(prison);
+}
+EXPORT_SYMBOL_GPL(dm_bio_prison_destroy);
+
+static uint32_t hash_key(struct dm_bio_prison *prison, struct dm_cell_key *key)
+{
+ const unsigned long BIG_PRIME = 4294967291UL;
+ uint64_t hash = key->block * BIG_PRIME;
+
+ return (uint32_t) (hash & prison->hash_mask);
+}
+
+static int keys_equal(struct dm_cell_key *lhs, struct dm_cell_key *rhs)
+{
+ return (lhs->virtual == rhs->virtual) &&
+ (lhs->dev == rhs->dev) &&
+ (lhs->block == rhs->block);
+}
+
+static struct dm_bio_prison_cell *__search_bucket(struct hlist_head *bucket,
+ struct dm_cell_key *key)
+{
+ struct dm_bio_prison_cell *cell;
+ struct hlist_node *tmp;
+
+ hlist_for_each_entry(cell, tmp, bucket, list)
+ if (keys_equal(&cell->key, key))
+ return cell;
+
+ return NULL;
+}
+
+/*
+ * This may block if a new cell needs allocating. You must ensure that
+ * cells will be unlocked even if the calling thread is blocked.
+ *
+ * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
+ */
+int dm_bio_detain(struct dm_bio_prison *prison, struct dm_cell_key *key,
+ struct bio *inmate, struct dm_bio_prison_cell **ref)
+{
+ int r = 1;
+ unsigned long flags;
+ uint32_t hash = hash_key(prison, key);
+ struct dm_bio_prison_cell *cell, *cell2;
+
+ BUG_ON(hash > prison->nr_buckets);
+
+ spin_lock_irqsave(&prison->lock, flags);
+
+ cell = __search_bucket(prison->cells + hash, key);
+ if (cell) {
+ bio_list_add(&cell->bios, inmate);
+ goto out;
+ }
+
+ /*
+ * Allocate a new cell
+ */
+ spin_unlock_irqrestore(&prison->lock, flags);
+ cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO);
+ spin_lock_irqsave(&prison->lock, flags);
+
+ /*
+ * We've been unlocked, so we have to double check that
+ * nobody else has inserted this cell in the meantime.
+ */
+ cell = __search_bucket(prison->cells + hash, key);
+ if (cell) {
+ mempool_free(cell2, prison->cell_pool);
+ bio_list_add(&cell->bios, inmate);
+ goto out;
+ }
+
+ /*
+ * Use new cell.
+ */
+ cell = cell2;
+
+ cell->prison = prison;
+ memcpy(&cell->key, key, sizeof(cell->key));
+ cell->holder = inmate;
+ bio_list_init(&cell->bios);
+ hlist_add_head(&cell->list, prison->cells + hash);
+
+ r = 0;
+
+out:
+ spin_unlock_irqrestore(&prison->lock, flags);
+
+ *ref = cell;
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_bio_detain);
+
+/*
+ * @inmates must have been initialised prior to this call
+ */
+static void __cell_release(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
+{
+ struct dm_bio_prison *prison = cell->prison;
+
+ hlist_del(&cell->list);
+
+ if (inmates) {
+ bio_list_add(inmates, cell->holder);
+ bio_list_merge(inmates, &cell->bios);
+ }
+
+ mempool_free(cell, prison->cell_pool);
+}
+
+void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios)
+{
+ unsigned long flags;
+ struct dm_bio_prison *prison = cell->prison;
+
+ spin_lock_irqsave(&prison->lock, flags);
+ __cell_release(cell, bios);
+ spin_unlock_irqrestore(&prison->lock, flags);
+}
+EXPORT_SYMBOL_GPL(dm_cell_release);
+
+/*
+ * There are a couple of places where we put a bio into a cell briefly
+ * before taking it out again. In these situations we know that no other
+ * bio may be in the cell. This function releases the cell, and also does
+ * a sanity check.
+ */
+static void __cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
+{
+ BUG_ON(cell->holder != bio);
+ BUG_ON(!bio_list_empty(&cell->bios));
+
+ __cell_release(cell, NULL);
+}
+
+void dm_cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
+{
+ unsigned long flags;
+ struct dm_bio_prison *prison = cell->prison;
+
+ spin_lock_irqsave(&prison->lock, flags);
+ __cell_release_singleton(cell, bio);
+ spin_unlock_irqrestore(&prison->lock, flags);
+}
+EXPORT_SYMBOL_GPL(dm_cell_release_singleton);
+
+/*
+ * Sometimes we don't want the holder, just the additional bios.
+ */
+static void __cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
+{
+ struct dm_bio_prison *prison = cell->prison;
+
+ hlist_del(&cell->list);
+ bio_list_merge(inmates, &cell->bios);
+
+ mempool_free(cell, prison->cell_pool);
+}
+
+void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
+{
+ unsigned long flags;
+ struct dm_bio_prison *prison = cell->prison;
+
+ spin_lock_irqsave(&prison->lock, flags);
+ __cell_release_no_holder(cell, inmates);
+ spin_unlock_irqrestore(&prison->lock, flags);
+}
+EXPORT_SYMBOL_GPL(dm_cell_release_no_holder);
+
+void dm_cell_error(struct dm_bio_prison_cell *cell)
+{
+ struct dm_bio_prison *prison = cell->prison;
+ struct bio_list bios;
+ struct bio *bio;
+ unsigned long flags;
+
+ bio_list_init(&bios);
+
+ spin_lock_irqsave(&prison->lock, flags);
+ __cell_release(cell, &bios);
+ spin_unlock_irqrestore(&prison->lock, flags);
+
+ while ((bio = bio_list_pop(&bios)))
+ bio_io_error(bio);
+}
+EXPORT_SYMBOL_GPL(dm_cell_error);
+
+/*----------------------------------------------------------------*/
+
+#define DEFERRED_SET_SIZE 64
+
+struct dm_deferred_entry {
+ struct dm_deferred_set *ds;
+ unsigned count;
+ struct list_head work_items;
+};
+
+struct dm_deferred_set {
+ spinlock_t lock;
+ unsigned current_entry;
+ unsigned sweeper;
+ struct dm_deferred_entry entries[DEFERRED_SET_SIZE];
+};
+
+struct dm_deferred_set *dm_deferred_set_create(void)
+{
+ int i;
+ struct dm_deferred_set *ds;
+
+ ds = kmalloc(sizeof(*ds), GFP_KERNEL);
+ if (!ds)
+ return NULL;
+
+ spin_lock_init(&ds->lock);
+ ds->current_entry = 0;
+ ds->sweeper = 0;
+ for (i = 0; i < DEFERRED_SET_SIZE; i++) {
+ ds->entries[i].ds = ds;
+ ds->entries[i].count = 0;
+ INIT_LIST_HEAD(&ds->entries[i].work_items);
+ }
+
+ return ds;
+}
+EXPORT_SYMBOL_GPL(dm_deferred_set_create);
+
+void dm_deferred_set_destroy(struct dm_deferred_set *ds)
+{
+ kfree(ds);
+}
+EXPORT_SYMBOL_GPL(dm_deferred_set_destroy);
+
+struct dm_deferred_entry *dm_deferred_entry_inc(struct dm_deferred_set *ds)
+{
+ unsigned long flags;
+ struct dm_deferred_entry *entry;
+
+ spin_lock_irqsave(&ds->lock, flags);
+ entry = ds->entries + ds->current_entry;
+ entry->count++;
+ spin_unlock_irqrestore(&ds->lock, flags);
+
+ return entry;
+}
+EXPORT_SYMBOL_GPL(dm_deferred_entry_inc);
+
+static unsigned ds_next(unsigned index)
+{
+ return (index + 1) % DEFERRED_SET_SIZE;
+}
+
+static void __sweep(struct dm_deferred_set *ds, struct list_head *head)
+{
+ while ((ds->sweeper != ds->current_entry) &&
+ !ds->entries[ds->sweeper].count) {
+ list_splice_init(&ds->entries[ds->sweeper].work_items, head);
+ ds->sweeper = ds_next(ds->sweeper);
+ }
+
+ if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count)
+ list_splice_init(&ds->entries[ds->sweeper].work_items, head);
+}
+
+void dm_deferred_entry_dec(struct dm_deferred_entry *entry, struct list_head *head)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&entry->ds->lock, flags);
+ BUG_ON(!entry->count);
+ --entry->count;
+ __sweep(entry->ds, head);
+ spin_unlock_irqrestore(&entry->ds->lock, flags);
+}
+EXPORT_SYMBOL_GPL(dm_deferred_entry_dec);
+
+/*
+ * Returns 1 if deferred or 0 if no pending items to delay job.
+ */
+int dm_deferred_set_add_work(struct dm_deferred_set *ds, struct list_head *work)
+{
+ int r = 1;
+ unsigned long flags;
+ unsigned next_entry;
+
+ spin_lock_irqsave(&ds->lock, flags);
+ if ((ds->sweeper == ds->current_entry) &&
+ !ds->entries[ds->current_entry].count)
+ r = 0;
+ else {
+ list_add(work, &ds->entries[ds->current_entry].work_items);
+ next_entry = ds_next(ds->current_entry);
+ if (!ds->entries[next_entry].count)
+ ds->current_entry = next_entry;
+ }
+ spin_unlock_irqrestore(&ds->lock, flags);
+
+ return r;
+}
+EXPORT_SYMBOL_GPL(dm_deferred_set_add_work);
+
+/*----------------------------------------------------------------*/
+
+static int __init dm_bio_prison_init(void)
+{
+ _cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0);
+ if (!_cell_cache)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void __exit dm_bio_prison_exit(void)
+{
+ kmem_cache_destroy(_cell_cache);
+ _cell_cache = NULL;
+}
+
+/*
+ * module hooks
+ */
+module_init(dm_bio_prison_init);
+module_exit(dm_bio_prison_exit);
+
+MODULE_DESCRIPTION(DM_NAME " bio prison");
+MODULE_AUTHOR("Joe Thornber <[email protected]>");
+MODULE_LICENSE("GPL");

drivers/md/dm-bio-prison.h

View file
diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h
new file mode 100644
index 0000000..4e0ac37
--- /dev/null
+++ b/drivers/md/dm-bio-prison.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2011-2012 Red Hat, Inc.
+ *
+ * This file is released under the GPL.
+ */
+
+#ifndef DM_BIO_PRISON_H
+#define DM_BIO_PRISON_H
+
+#include "persistent-data/dm-block-manager.h" /* FIXME: for dm_block_t */
+#include "dm-thin-metadata.h" /* FIXME: for dm_thin_id */
+
+#include <linux/list.h>
+#include <linux/bio.h>
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Sometimes we can't deal with a bio straight away. We put them in prison
+ * where they can't cause any mischief. Bios are put in a cell identified
+ * by a key, multiple bios can be in the same cell. When the cell is
+ * subsequently unlocked the bios become available.
+ */
+struct dm_bio_prison;
+struct dm_bio_prison_cell;
+
+/* FIXME: this needs to be more abstract */
+struct dm_cell_key {
+ int virtual;
+ dm_thin_id dev;
+ dm_block_t block;
+};
+
+struct dm_bio_prison *dm_bio_prison_create(unsigned nr_cells);
+void dm_bio_prison_destroy(struct dm_bio_prison *prison);
+
+/*
+ * This may block if a new cell needs allocating. You must ensure that
+ * cells will be unlocked even if the calling thread is blocked.
+ *
+ * Returns 1 if the cell was already held, 0 if @inmate is the new holder.
+ */
+int dm_bio_detain(struct dm_bio_prison *prison, struct dm_cell_key *key,
+ struct bio *inmate, struct dm_bio_prison_cell **ref);
+
+void dm_cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios);
+void dm_cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio); // FIXME: bio arg not needed
+void dm_cell_release_no_holder(struct dm_bio_prison_cell *cell, struct bio_list *inmates);
+void dm_cell_error(struct dm_bio_prison_cell *cell);
+
+/*----------------------------------------------------------------*/
+
+/*
+ * We use the deferred set to keep track of pending reads to shared blocks.
+ * We do this to ensure the new mapping caused by a write isn't performed
+ * until these prior reads have completed. Otherwise the insertion of the
+ * new mapping could free the old block that the read bios are mapped to.
+ */
+
+struct dm_deferred_set;
+struct dm_deferred_entry;
+
+struct dm_deferred_set *dm_deferred_set_create(void);
+void dm_deferred_set_destroy(struct dm_deferred_set *ds);
+
+struct dm_deferred_entry *dm_deferred_entry_inc(struct dm_deferred_set *ds);
+void dm_deferred_entry_dec(struct dm_deferred_entry *entry, struct list_head *head);
+int dm_deferred_set_add_work(struct dm_deferred_set *ds, struct list_head *work);
+
+/*----------------------------------------------------------------*/
+
+#endif

drivers/md/dm-bufio.c

View file
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index cc06a1e..651ca79 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -280,9 +280,7 @@ static void __cache_size_refresh(void)
BUG_ON(!mutex_is_locked(&dm_bufio_clients_lock));
BUG_ON(dm_bufio_client_count < 0);
- dm_bufio_cache_size_latch = dm_bufio_cache_size;
-
- barrier();
+ dm_bufio_cache_size_latch = ACCESS_ONCE(dm_bufio_cache_size);
/*
* Use default if set to 0 and report the actual cache size used.
@@ -441,8 +439,7 @@ static void __relink_lru(struct dm_buffer *b, int dirty)
c->n_buffers[b->list_mode]--;
c->n_buffers[dirty]++;
b->list_mode = dirty;
- list_del(&b->lru_list);
- list_add(&b->lru_list, &c->lru[dirty]);
+ list_move(&b->lru_list, &c->lru[dirty]);
}
/*----------------------------------------------------------------
@@ -813,7 +810,7 @@ static void __get_memory_limit(struct dm_bufio_client *c,
{
unsigned long buffers;
- if (dm_bufio_cache_size != dm_bufio_cache_size_latch) {
+ if (ACCESS_ONCE(dm_bufio_cache_size) != dm_bufio_cache_size_latch) {
mutex_lock(&dm_bufio_clients_lock);
__cache_size_refresh();
mutex_unlock(&dm_bufio_clients_lock);
@@ -1591,11 +1588,9 @@ EXPORT_SYMBOL_GPL(dm_bufio_client_destroy);
static void cleanup_old_buffers(void)
{
- unsigned long max_age = dm_bufio_max_age;
+ unsigned long max_age = ACCESS_ONCE(dm_bufio_max_age);
struct dm_bufio_client *c;
- barrier();
-
if (max_age > ULONG_MAX / HZ)
max_age = ULONG_MAX / HZ;

drivers/md/dm-mpath.c

View file
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index d778563..573bd04 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1309,13 +1309,14 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
{
struct multipath *m = ti->private;
struct dm_mpath_io *mpio = map_context->ptr;
- struct pgpath *pgpath = mpio->pgpath;
+ struct pgpath *pgpath;
struct path_selector *ps;
int r;
BUG_ON(!mpio);
r = do_end_io(m, clone, error, mpio);

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drivers/md/dm-thin.c

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drivers/md/dm-verity.c

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drivers/md/dm.c

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drivers/md/persistent-data/dm-space-map-common.c

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