On Tue 11-06-24 14:06:24, Mateusz Guzik wrote:
> new_inode used to have the following:
> spin_lock(&inode_lock);
> inodes_stat.nr_inodes++;
> list_add(&inode->i_list, &inode_in_use);
> list_add(&inode->i_sb_list, &sb->s_inodes);
> inode->i_ino = ++last_ino;
> inode->i_state = 0;
> spin_unlock(&inode_lock);
>
> over time things disappeared, got moved around or got replaced (global
> inode lock with a per-inode lock), eventually this got reduced to:
> spin_lock(&inode->i_lock);
> inode->i_state = 0;
> spin_unlock(&inode->i_lock);
>
> But the lock acquire here does not synchronize against anyone.
>
> Additionally iget5_locked performs i_state = 0 assignment without any
> locks to begin with, the two combined look confusing at best.
>
> It looks like the current state is a leftover which was not cleaned up.
>
> Ideally it would be an invariant that i_state == 0 to begin with, but
> achieving that would require dealing with all filesystem alloc handlers
> one by one.
>
> In the meantime drop the misleading locking and move i_state zeroing to
> inode_init_always so that others don't need to deal with it by hand.
>
> Signed-off-by: Mateusz Guzik <[email protected]>
Just one nit below:
> diff --git a/fs/inode.c b/fs/inode.c
> index 3a4c67bfe085..8f05d79de01d 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -231,6 +231,8 @@ int inode_init_always(struct super_block *sb, struct
> inode *inode)
>
> if (unlikely(security_inode_alloc(inode)))
> return -ENOMEM;
> +
> + inode->i_state = 0;
> this_cpu_inc(nr_inodes);
This would be more logical above where inode content is initialized (and
less errorprone just in case security_inode_alloc() grows dependency on
i_state value) - like just after:
inode->i_flags = 0;
With that fixed feel free to add:
Reviewed-by: Jan Kara <[email protected]>
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
