From: Muchun Song <songmuchun@xxxxxxxxxxxxx> Subject: fs: introduce alloc_inode_sb() to allocate filesystems specific inode The allocated inode cache is supposed to be added to its memcg list_lru which should be allocated as well in advance. That can be done by kmem_cache_alloc_lru() which allocates object and list_lru. The file systems is main user of it. So introduce alloc_inode_sb() to allocate file system specific inodes and set up the inode reclaim context properly. The file system is supposed to use alloc_inode_sb() to allocate inodes. In the later patches, we will convert all users to the new API. Link: https://lkml.kernel.org/r/20220228122126.37293-4-songmuchun@xxxxxxxxxxxxx Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> Reviewed-by: Roman Gushchin <roman.gushchin@xxxxxxxxx> Cc: Alex Shi <alexs@xxxxxxxxxx> Cc: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx> Cc: Chao Yu <chao@xxxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Fam Zheng <fam.zheng@xxxxxxxxxxxxx> Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Kari Argillander <kari.argillander@xxxxxxxxx> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Theodore Ts'o <tytso@xxxxxxx> Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Wei Yang <richard.weiyang@xxxxxxxxx> Cc: Xiongchun Duan <duanxiongchun@xxxxxxxxxxxxx> Cc: Yang Shi <shy828301@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/filesystems/porting.rst | 6 ++++++ fs/inode.c | 2 +- include/linux/fs.h | 11 +++++++++++ 3 files changed, 18 insertions(+), 1 deletion(-) --- a/Documentation/filesystems/porting.rst~fs-introduce-alloc_inode_sb-to-allocate-filesystems-specific-inode +++ a/Documentation/filesystems/porting.rst @@ -45,6 +45,12 @@ typically between calling iget_locked() At some point that will become mandatory. +**mandatory** + +The foo_inode_info should always be allocated through alloc_inode_sb() rather +than kmem_cache_alloc() or kmalloc() related to set up the inode reclaim context +correctly. + --- **mandatory** --- a/fs/inode.c~fs-introduce-alloc_inode_sb-to-allocate-filesystems-specific-inode +++ a/fs/inode.c @@ -259,7 +259,7 @@ static struct inode *alloc_inode(struct if (ops->alloc_inode) inode = ops->alloc_inode(sb); else - inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL); + inode = alloc_inode_sb(sb, inode_cachep, GFP_KERNEL); if (!inode) return NULL; --- a/include/linux/fs.h~fs-introduce-alloc_inode_sb-to-allocate-filesystems-specific-inode +++ a/include/linux/fs.h @@ -42,6 +42,7 @@ #include <linux/mount.h> #include <linux/cred.h> #include <linux/mnt_idmapping.h> +#include <linux/slab.h> #include <asm/byteorder.h> #include <uapi/linux/fs.h> @@ -3114,6 +3115,16 @@ extern void free_inode_nonrcu(struct ino extern int should_remove_suid(struct dentry *); extern int file_remove_privs(struct file *); +/* + * This must be used for allocating filesystems specific inodes to set + * up the inode reclaim context correctly. + */ +static inline void * +alloc_inode_sb(struct super_block *sb, struct kmem_cache *cache, gfp_t gfp) +{ + return kmem_cache_alloc_lru(cache, &sb->s_inode_lru, gfp); +} + extern void __insert_inode_hash(struct inode *, unsigned long hashval); static inline void insert_inode_hash(struct inode *inode) { _
