Re: [PATCH RFC v2 2/3] pidfs: remove 32bit inode number handling

Jan Kara
2024-12-02T15:18:37Z

On Fri 29-11-24 14:02:24, Christian Brauner wrote:
> Now that we have a unified inode number handling model remove the custom
> ida-based allocation for 32bit.
>
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> fs/pidfs.c | 46 +++++-----------------------------------------
> 1 file changed, 5 insertions(+), 41 deletions(-)
>
> diff --git a/fs/pidfs.c b/fs/pidfs.c
> index 0bdd9c525b80895d33f2eae5e8e375788580072f..ff4f25078f3d983bce630e597adbb12262e5d727 100644
> --- a/fs/pidfs.c
> +++ b/fs/pidfs.c
> @@ -371,40 +371,6 @@ struct pid *pidfd_pid(const struct file *file)
>
> static struct vfsmount *pidfs_mnt __ro_after_init;
>
> -#if BITS_PER_LONG == 32
> -/*
> - * Provide a fallback mechanism for 32-bit systems so processes remain
> - * reliably comparable by inode number even on those systems.
> - */
> -static DEFINE_IDA(pidfd_inum_ida);
> -
> -static int pidfs_inum(struct pid *pid, unsigned long *ino)
> -{
> - int ret;
> -
> - ret = ida_alloc_range(&pidfd_inum_ida, RESERVED_PIDS + 1,
> - UINT_MAX, GFP_ATOMIC);
> - if (ret < 0)
> - return -ENOSPC;
> -
> - *ino = ret;
> - return 0;
> -}
> -
> -static inline void pidfs_free_inum(unsigned long ino)
> -{
> - if (ino > 0)
> - ida_free(&pidfd_inum_ida, ino);
> -}
> -#else
> -static inline int pidfs_inum(struct pid *pid, unsigned long *ino)
> -{
> - *ino = pid->ino;
> - return 0;
> -}
> -#define pidfs_free_inum(ino) ((void)(ino))
> -#endif
> -
> /*
> * The vfs falls back to simple_setattr() if i_op->setattr() isn't
> * implemented. Let's reject it completely until we have a clean
> @@ -456,7 +422,6 @@ static void pidfs_evict_inode(struct inode *inode)
>
> clear_inode(inode);
> put_pid(pid);
> - pidfs_free_inum(inode->i_ino);
> }
>
> static const struct super_operations pidfs_sops = {
> @@ -482,17 +447,16 @@ static const struct dentry_operations pidfs_dentry_operations = {
>
> static int pidfs_init_inode(struct inode *inode, void *data)
> {
> + struct pid *pid = data;
> +
> inode->i_private = data;
> inode->i_flags |= S_PRIVATE;
> inode->i_mode |= S_IRWXU;
> inode->i_op = &pidfs_inode_operations;
> inode->i_fop = &pidfs_file_operations;
> - /*
> - * Inode numbering for pidfs start at RESERVED_PIDS + 1. This
> - * avoids collisions with the root inode which is 1 for pseudo
> - * filesystems.
> - */
> - return pidfs_inum(data, &inode->i_ino);
> + inode->i_ino = pidfs_ino(pid->ino);
> + inode->i_generation = pidfs_gen(pid->ino);
> + return 0;
> }
>
> static void pidfs_put_data(void *data)
>
> --
> 2.45.2
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR