diff options
| -rw-r--r-- | drivers/md/dm.c | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 6e65d85d082..a5cc4c8462f 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -63,6 +63,7 @@ union map_info *dm_get_mapinfo(struct bio *bio) #define DMF_BLOCK_IO 0 #define DMF_SUSPENDED 1 #define DMF_FROZEN 2 +#define DMF_FREEING 3 struct mapped_device { struct rw_semaphore io_lock; @@ -221,9 +222,23 @@ static int dm_blk_open(struct inode *inode, struct file *file) { struct mapped_device *md; + spin_lock(&_minor_lock); + md = inode->i_bdev->bd_disk->private_data; + if (!md) + goto out; + + if (test_bit(DMF_FREEING, &md->flags)) { + md = NULL; + goto out; + } + dm_get(md); - return 0; + +out: + spin_unlock(&_minor_lock); + + return md ? 0 : -ENXIO; } static int dm_blk_close(struct inode *inode, struct file *file) @@ -919,6 +934,11 @@ static void free_dev(struct mapped_device *md) mempool_destroy(md->io_pool); del_gendisk(md->disk); free_minor(minor); + + spin_lock(&_minor_lock); + md->disk->private_data = NULL; + spin_unlock(&_minor_lock); + put_disk(md->disk); blk_cleanup_queue(md->queue); kfree(md); @@ -1023,9 +1043,14 @@ static struct mapped_device *dm_find_md(dev_t dev) spin_lock(&_minor_lock); md = idr_find(&_minor_idr, minor); - if (md && (md == MINOR_ALLOCED || (dm_disk(md)->first_minor != minor))) + if (md && (md == MINOR_ALLOCED || + (dm_disk(md)->first_minor != minor) || + test_bit(DMF_FREEING, &md->flags))) { md = NULL; + goto out; + } +out: spin_unlock(&_minor_lock); return md; @@ -1060,9 +1085,12 @@ void dm_put(struct mapped_device *md) { struct dm_table *map; + BUG_ON(test_bit(DMF_FREEING, &md->flags)); + if (atomic_dec_and_lock(&md->holders, &_minor_lock)) { map = dm_get_table(md); idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor); + set_bit(DMF_FREEING, &md->flags); spin_unlock(&_minor_lock); if (!dm_suspended(md)) { dm_table_presuspend_targets(map); |