Commit 9860f434 authored by Ryusuke Konishi's avatar Ryusuke Konishi Committed by Andrew Morton
Browse files

nilfs2: eliminate the shared counter and spinlock for i_generation 

Use get_random_u32() as the source for inode->i_generation for new inodes,
and eliminate the original source, the shared counter ns_next_generation
along with its exclusive access spinlock ns_next_gen_lock.

Link: https://lkml.kernel.org/r/20240826174116.5008-5-konishi.ryusuke@gmail.com


Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Huang Xiaojia <huangxiaojia2@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent d7cee0b3

fs/nilfs2/inode.c

+2 −4
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <linux/writeback.h>

#include <linux/uio.h>

#include <linux/fiemap.h>

#include <linux/random.h>

#include "nilfs.h"

#include "btnode.h"

#include "segment.h"
@@ -320,7 +321,6 @@ static int nilfs_insert_inode_locked(struct inode *inode, 
struct inode *nilfs_new_inode(struct inode *dir, umode_t mode)

{

	struct super_block *sb = dir->i_sb;

	struct the_nilfs *nilfs = sb->s_fs_info;

	struct inode *inode;

	struct nilfs_inode_info *ii;

	struct nilfs_root *root;
@@ -381,9 +381,7 @@ struct inode *nilfs_new_inode(struct inode *dir, umode_t mode) 
	/* ii->i_dir_acl = 0; */

	ii->i_dir_start_lookup = 0;

	nilfs_set_inode_flags(inode);

	spin_lock(&nilfs->ns_next_gen_lock);

	inode->i_generation = nilfs->ns_next_generation++;

	spin_unlock(&nilfs->ns_next_gen_lock);

	inode->i_generation = get_random_u32();

	if (nilfs_insert_inode_locked(inode, root, ino) < 0) {

		err = -EIO;

		goto failed_after_creation;

fs/nilfs2/the_nilfs.c

+0 −5
Original line number Diff line number Diff line
@@ -12,7 +12,6 @@ 
#include <linux/slab.h>

#include <linux/blkdev.h>

#include <linux/backing-dev.h>

#include <linux/random.h>

#include <linux/log2.h>

#include <linux/crc32.h>

#include "nilfs.h"
@@ -69,7 +68,6 @@ struct the_nilfs *alloc_nilfs(struct super_block *sb) 
	INIT_LIST_HEAD(&nilfs->ns_dirty_files);

	INIT_LIST_HEAD(&nilfs->ns_gc_inodes);

	spin_lock_init(&nilfs->ns_inode_lock);

	spin_lock_init(&nilfs->ns_next_gen_lock);

	spin_lock_init(&nilfs->ns_last_segment_lock);

	nilfs->ns_cptree = RB_ROOT;

	spin_lock_init(&nilfs->ns_cptree_lock);
@@ -754,9 +752,6 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb) 
	nilfs->ns_blocksize_bits = sb->s_blocksize_bits;

	nilfs->ns_blocksize = blocksize;



	get_random_bytes(&nilfs->ns_next_generation,

			 sizeof(nilfs->ns_next_generation));



	err = nilfs_store_disk_layout(nilfs, sbp);

	if (err)

		goto failed_sbh;

fs/nilfs2/the_nilfs.h

+0 −6
Original line number Diff line number Diff line
@@ -71,8 +71,6 @@ enum { 
 * @ns_dirty_files: list of dirty files

 * @ns_inode_lock: lock protecting @ns_dirty_files

 * @ns_gc_inodes: dummy inodes to keep live blocks

 * @ns_next_generation: next generation number for inodes

 * @ns_next_gen_lock: lock protecting @ns_next_generation

 * @ns_mount_opt: mount options

 * @ns_resuid: uid for reserved blocks

 * @ns_resgid: gid for reserved blocks
@@ -161,10 +159,6 @@ struct the_nilfs { 
	/* GC inode list */

	struct list_head	ns_gc_inodes;



	/* Inode allocator */

	u32			ns_next_generation;

	spinlock_t		ns_next_gen_lock;



	/* Mount options */

	unsigned long		ns_mount_opt;