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: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Huang Xiaojia <huangxiaojia2@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 35f966cb4ece34bd452b72b829744ec0cb54c166..3c4a0577bc714d29fa0e44f2787d77dc89cc16fa 100644 (file)
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -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;

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index e44dde57ab652bb02447f1e79490a630a36b900f..ac03fd3c330c66678f334b2fe669b38ba1cc4078 100644 (file)
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -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;

diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index 1e829ed7b0ef56ffe57d099dfa3a18f674f46f55..4776a70f01ae85eebb058aefcc42c7e29d0f4096 100644 (file)
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -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;