On Mon, Nov 08, 2021 at 04:05:26AM +0000, Matthew Wilcox (Oracle) wrote:
> Instead of setting a bit in the fs_flags to set a bit in the
> address_space, set the bit in the address_space directly.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Makes sense,
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> fs/inode.c | 2 --
> include/linux/fs.h | 1 -
> include/linux/pagemap.h | 16 ++++++++++++++++
> mm/shmem.c | 3 ++-
> 4 files changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 9abc88d7959c..d6386b6d5a6e 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -180,8 +180,6 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
> mapping->a_ops = &empty_aops;
> mapping->host = inode;
> mapping->flags = 0;
> - if (sb->s_type->fs_flags & FS_THP_SUPPORT)
> - __set_bit(AS_THP_SUPPORT, &mapping->flags);
> mapping->wb_err = 0;
> atomic_set(&mapping->i_mmap_writable, 0);
> #ifdef CONFIG_READ_ONLY_THP_FOR_FS
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 4137a9bfae7a..3c2fcabf9d12 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2518,7 +2518,6 @@ struct file_system_type {
> #define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */
> #define FS_DISALLOW_NOTIFY_PERM 16 /* Disable fanotify permission events */
> #define FS_ALLOW_IDMAP 32 /* FS has been updated to handle vfs idmappings. */
> -#define FS_THP_SUPPORT 8192 /* Remove once all fs converted */
> #define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */
> int (*init_fs_context)(struct fs_context *);
> const struct fs_parameter_spec *parameters;
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index db2c3e3eb1cf..471f0c422831 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -126,6 +126,22 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
> m->gfp_mask = mask;
> }
>
> +/**
> + * mapping_set_large_folios() - Indicate the file supports multi-page folios.
> + * @mapping: The file.
> + *
> + * The filesystem should call this function in its inode constructor to
> + * indicate that the VFS can use multi-page folios to cache the contents
> + * of the file.
> + *
> + * Context: This should not be called while the inode is active as it
> + * is non-atomic.
> + */
> +static inline void mapping_set_large_folios(struct address_space *mapping)
> +{
> + __set_bit(AS_THP_SUPPORT, &mapping->flags);
> +}
> +
> static inline bool mapping_thp_support(struct address_space *mapping)
> {
> return test_bit(AS_THP_SUPPORT, &mapping->flags);
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 23c91a8beb78..54422933fa2d 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2303,6 +2303,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
> INIT_LIST_HEAD(&info->swaplist);
> simple_xattrs_init(&info->xattrs);
> cache_no_acl(inode);
> + mapping_set_large_folios(inode->i_mapping);
>
> switch (mode & S_IFMT) {
> default:
> @@ -3920,7 +3921,7 @@ static struct file_system_type shmem_fs_type = {
> .parameters = shmem_fs_parameters,
> #endif
> .kill_sb = kill_litter_super,
> - .fs_flags = FS_USERNS_MOUNT | FS_THP_SUPPORT,
> + .fs_flags = FS_USERNS_MOUNT,
> };
>
> int __init shmem_init(void)
> --
> 2.33.0
>
