diff options
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 56a2c74c9a3f..58f3927fd7cc 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -142,6 +142,9 @@ struct mapped_device { */ struct dm_table *map; + struct list_head table_devices; + struct mutex table_devices_lock; + unsigned long flags; struct request_queue *queue; @@ -212,6 +215,12 @@ struct dm_md_mempools { struct bio_set *bs; }; +struct table_device { + struct list_head list; + atomic_t count; + struct dm_dev dm_dev; +}; + #define RESERVED_BIO_BASED_IOS 16 #define RESERVED_REQUEST_BASED_IOS 256 #define RESERVED_MAX_IOS 1024 @@ -670,6 +679,120 @@ static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU) } /* + * Open a table device so we can use it as a map destination. + */ +static int open_table_device(struct table_device *td, dev_t dev, + struct mapped_device *md) +{ + static char *_claim_ptr = "I belong to device-mapper"; + struct block_device *bdev; + + int r; + + BUG_ON(td->dm_dev.bdev); + + bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _claim_ptr); + if (IS_ERR(bdev)) + return PTR_ERR(bdev); + + r = bd_link_disk_holder(bdev, dm_disk(md)); + if (r) { + blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL); + return r; + } + + td->dm_dev.bdev = bdev; + return 0; +} + +/* + * Close a table device that we've been using. + */ +static void close_table_device(struct table_device *td, struct mapped_device *md) +{ + if (!td->dm_dev.bdev) + return; + + bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md)); + blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL); + td->dm_dev.bdev = NULL; +} + +static struct table_device *find_table_device(struct list_head *l, dev_t dev, + fmode_t mode) { + struct table_device *td; + + list_for_each_entry(td, l, list) + if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode) + return td; + + return NULL; +} + +int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode, + struct dm_dev **result) { + int r; + struct table_device *td; + + mutex_lock(&md->table_devices_lock); + td = find_table_device(&md->table_devices, dev, mode); + if (!td) { + td = kmalloc(sizeof(*td), GFP_KERNEL); + if (!td) { + mutex_unlock(&md->table_devices_lock); + return -ENOMEM; + } + + td->dm_dev.mode = mode; + td->dm_dev.bdev = NULL; + + if ((r = open_table_device(td, dev, md))) { + mutex_unlock(&md->table_devices_lock); + kfree(td); + return r; + } + + format_dev_t(td->dm_dev.name, dev); + + atomic_set(&td->count, 0); + list_add(&td->list, &md->table_devices); + } + atomic_inc(&td->count); + mutex_unlock(&md->table_devices_lock); + + *result = &td->dm_dev; + return 0; +} +EXPORT_SYMBOL_GPL(dm_get_table_device); + +void dm_put_table_device(struct mapped_device *md, struct dm_dev *d) +{ + struct table_device *td = container_of(d, struct table_device, dm_dev); + + mutex_lock(&md->table_devices_lock); + if (atomic_dec_and_test(&td->count)) { + close_table_device(td, md); + list_del(&td->list); + kfree(td); + } + mutex_unlock(&md->table_devices_lock); +} +EXPORT_SYMBOL(dm_put_table_device); + +static void free_table_devices(struct list_head *devices) +{ + struct list_head *tmp, *next; + + list_for_each_safe(tmp, next, devices) { + struct table_device *td = list_entry(tmp, struct table_device, list); + + DMWARN("dm_destroy: %s still exists with %d references", + td->dm_dev.name, atomic_read(&td->count)); + kfree(td); + } +} + +/* * Get the geometry associated with a dm device */ int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo) @@ -1944,12 +2067,14 @@ static struct mapped_device *alloc_dev(int minor) md->type = DM_TYPE_NONE; mutex_init(&md->suspend_lock); mutex_init(&md->type_lock); + mutex_init(&md->table_devices_lock); spin_lock_init(&md->deferred_lock); atomic_set(&md->holders, 1); atomic_set(&md->open_count, 0); atomic_set(&md->event_nr, 0); atomic_set(&md->uevent_seq, 0); INIT_LIST_HEAD(&md->uevent_list); + INIT_LIST_HEAD(&md->table_devices); spin_lock_init(&md->uevent_lock); md->queue = blk_alloc_queue(GFP_KERNEL); @@ -2035,6 +2160,7 @@ static void free_dev(struct mapped_device *md) blk_integrity_unregister(md->disk); del_gendisk(md->disk); cleanup_srcu_struct(&md->io_barrier); + free_table_devices(&md->table_devices); free_minor(minor); spin_lock(&_minor_lock); |