btrfs: polish names of kmem caches

Usecase:

  watch 'grep btrfs < /proc/slabinfo'

easy to watch all caches in one go.

Signed-off-by: David Sterba <dsterba@suse.cz>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 9b21cf9..aae5562 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7155,31 +7155,31 @@
 
 int btrfs_init_cachep(void)
 {
-	btrfs_inode_cachep = kmem_cache_create("btrfs_inode_cache",
+	btrfs_inode_cachep = kmem_cache_create("btrfs_inode",
 			sizeof(struct btrfs_inode), 0,
 			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, init_once);
 	if (!btrfs_inode_cachep)
 		goto fail;
 
-	btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle_cache",
+	btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
 			sizeof(struct btrfs_trans_handle), 0,
 			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 	if (!btrfs_trans_handle_cachep)
 		goto fail;
 
-	btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction_cache",
+	btrfs_transaction_cachep = kmem_cache_create("btrfs_transaction",
 			sizeof(struct btrfs_transaction), 0,
 			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 	if (!btrfs_transaction_cachep)
 		goto fail;
 
-	btrfs_path_cachep = kmem_cache_create("btrfs_path_cache",
+	btrfs_path_cachep = kmem_cache_create("btrfs_path",
 			sizeof(struct btrfs_path), 0,
 			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 	if (!btrfs_path_cachep)
 		goto fail;
 
-	btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space_cache",
+	btrfs_free_space_cachep = kmem_cache_create("btrfs_free_space",
 			sizeof(struct btrfs_free_space), 0,
 			SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL);
 	if (!btrfs_free_space_cachep)