On Thu, Jul 31, 2008 at 01:42:01PM -0700, Mark Fasheh wrote:
> @@ -476,16 +515,18 @@ int ocfs2_reserve_local_alloc_bits(struct ocfs2_super
> *osb,
>
> mutex_lock(&local_alloc_inode->i_mutex);
>
> - if (osb->local_alloc_state != OCFS2_LA_ENABLED) {
> - status = -ENOSPC;
> - goto bail;
> - }
> -
> - if (bits_wanted > osb->local_alloc_bits) {
> - mlog(0, "Asking for more than my max window size!\n");
> + /*
> + * We must double check state and allocator bits because
> + * another process may have changed them while holding i_mutex.
> + */
> + spin_lock(&osb->osb_lock);
> + if (!ocfs2_la_state_enabled(osb) ||
> + (bits_wanted > osb->local_alloc_bits)) {
> + spin_unlock(&osb->osb_lock);
> status = -ENOSPC;
> goto bail;
> }
> + spin_unlock(&osb->osb_lock);
>
> alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
>
> @@ -513,6 +554,21 @@ int ocfs2_reserve_local_alloc_bits(struct ocfs2_super
> *osb,
> mlog_errno(status);
> goto bail;
> }
> +
> + /*
> + * Under certain conditions, the window slide code
> + * might have reduced the number of bits available or
> + * disabled the the local alloc entirely. Re-check
> + * here and return -ENOSPC if necessary.
> + */
> + status = -ENOSPC;
> + if (!ocfs2_la_state_enabled(osb))
> + goto bail;
> +
Up above you take osb_lock, here you don't. Now, if I read your
later comment correctly, you don't need osb_lock in either place,
because the read is safe under the mutex.
Joel
--
"Get right to the heart of matters.
It's the heart that matters more."
Joel Becker
Principal Software Developer
Oracle
E-mail: [EMAIL PROTECTED]
Phone: (650) 506-8127
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