nilfs2: simplify life cycle management of nilfs object
This stops pre-allocating nilfs object in nilfs_get_sb routine, and
stops managing its life cycle by reference counting.
nilfs_find_or_create_nilfs() function, nilfs->ns_mount_mutex,
nilfs_objects list, and the reference counter will be removed through
the simplification.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 960c287..6eeb4f0 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -35,9 +35,6 @@
#include "segbuf.h"
-static LIST_HEAD(nilfs_objects);
-static DEFINE_SPINLOCK(nilfs_lock);
-
static int nilfs_valid_sb(struct nilfs_super_block *sbp);
void nilfs_set_last_segment(struct the_nilfs *nilfs,
@@ -61,16 +58,13 @@
}
/**
- * alloc_nilfs - allocate the_nilfs structure
+ * alloc_nilfs - allocate a nilfs object
* @bdev: block device to which the_nilfs is related
*
- * alloc_nilfs() allocates memory for the_nilfs and
- * initializes its reference count and locks.
- *
* Return Value: On success, pointer to the_nilfs is returned.
* On error, NULL is returned.
*/
-static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
+struct the_nilfs *alloc_nilfs(struct block_device *bdev)
{
struct the_nilfs *nilfs;
@@ -79,12 +73,9 @@
return NULL;
nilfs->ns_bdev = bdev;
- atomic_set(&nilfs->ns_count, 1);
atomic_set(&nilfs->ns_ndirtyblks, 0);
init_rwsem(&nilfs->ns_sem);
- mutex_init(&nilfs->ns_mount_mutex);
init_rwsem(&nilfs->ns_writer_sem);
- INIT_LIST_HEAD(&nilfs->ns_list);
INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
spin_lock_init(&nilfs->ns_last_segment_lock);
nilfs->ns_cptree = RB_ROOT;
@@ -95,67 +86,11 @@
}
/**
- * find_or_create_nilfs - find or create nilfs object
- * @bdev: block device to which the_nilfs is related
- *
- * find_nilfs() looks up an existent nilfs object created on the
- * device and gets the reference count of the object. If no nilfs object
- * is found on the device, a new nilfs object is allocated.
- *
- * Return Value: On success, pointer to the nilfs object is returned.
- * On error, NULL is returned.
+ * destroy_nilfs - destroy nilfs object
+ * @nilfs: nilfs object to be released
*/
-struct the_nilfs *find_or_create_nilfs(struct block_device *bdev)
+void destroy_nilfs(struct the_nilfs *nilfs)
{
- struct the_nilfs *nilfs, *new = NULL;
-
- retry:
- spin_lock(&nilfs_lock);
- list_for_each_entry(nilfs, &nilfs_objects, ns_list) {
- if (nilfs->ns_bdev == bdev) {
- get_nilfs(nilfs);
- spin_unlock(&nilfs_lock);
- if (new)
- put_nilfs(new);
- return nilfs; /* existing object */
- }
- }
- if (new) {
- list_add_tail(&new->ns_list, &nilfs_objects);
- spin_unlock(&nilfs_lock);
- return new; /* new object */
- }
- spin_unlock(&nilfs_lock);
-
- new = alloc_nilfs(bdev);
- if (new)
- goto retry;
- return NULL; /* insufficient memory */
-}
-
-/**
- * put_nilfs - release a reference to the_nilfs
- * @nilfs: the_nilfs structure to be released
- *
- * put_nilfs() decrements a reference counter of the_nilfs.
- * If the reference count reaches zero, the_nilfs is freed.
- */
-void put_nilfs(struct the_nilfs *nilfs)
-{
- spin_lock(&nilfs_lock);
- if (!atomic_dec_and_test(&nilfs->ns_count)) {
- spin_unlock(&nilfs_lock);
- return;
- }
- list_del_init(&nilfs->ns_list);
- spin_unlock(&nilfs_lock);
-
- /*
- * Increment of ns_count never occurs below because the caller
- * of get_nilfs() holds at least one reference to the_nilfs.
- * Thus its exclusion control is not required here.
- */
-
might_sleep();
if (nilfs_loaded(nilfs)) {
nilfs_mdt_destroy(nilfs->ns_sufile);