Hi Josef,
On 09.03.2012 17:06, Josef Bacik wrote:
> I need to be able to safely deal with refs in my next patch, so convert refs and
Did I miss your next patch?
> pages_reading to ints and introduce an eb_lock spinlock so I can use this to
> safely manipulate the refs count when marking eb's as stale. Thanks,
I don't see what makes this version safer, are you synchronizing
eb->refs with eb->pages_reading? This would be strange, because
eb->pages_reading sounds like it could never be != 0 when eb->refs goes
down to 0. Could you extend your description a bit, please?
> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
> index f030a2d..d11e872 100644
> --- a/fs/btrfs/extent_io.h
> +++ b/fs/btrfs/extent_io.h
> @@ -128,8 +128,9 @@ struct extent_buffer {
> unsigned long map_len;
> unsigned long bflags;
> struct extent_io_tree *tree;
> - atomic_t refs;
> - atomic_t pages_reading;
> + spinlock_t eb_lock;
If you need that one, then please use another name for this. We already
have the extent buffer's rwlock, it'll only be a matter of time until
somebody (me) confuses eb->lock and eb->eb_lock. I'd like something
representing its purpose (which I didn't catch yet). eb->refs_lock or
eb->pages_lock might be appropriate.
> + int refs;
> + int pages_reading;
> struct list_head leak_list;
> struct rcu_head rcu_head;
> pid_t lock_owner;
Thanks,
-Jan
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