On 13/10/2014 23:39, Xin LI wrote: > Author: delphij > Date: Mon Oct 13 20:39:51 2014 > New Revision: 273060 > URL: https://svnweb.freebsd.org/changeset/base/273060 > > Log: > Use write_psize instead of write_asize when doing vdev_space_update. > Without this change the accounting of L2ARC usage would be wrong and > give 16EB free space because the number became negative and overflows. > > Obtained from: FreeNAS (issue #6239)
First, a link to the issue would be more convenient for reviewers. Here it is https://bugs.freenas.org/issues/6239 Then, I would like to see a technical explanation for this change. I could not find any explanation here or in the FreeNAS issue or in the FreeNAS commit. As far as I can see, all calls to vdev_space_update() in the ARC code are passed l2hdr->b_asize or a sum of b_asize fields of multiple buffers. Thus, I am really surprised with this change and would like to see reasoning behind it. > MFC after: 2 weeks > > Modified: > head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c > > Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c > ============================================================================== > --- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Mon Oct 13 > 19:05:18 2014 (r273059) > +++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Mon Oct 13 > 20:39:51 2014 (r273060) > @@ -5232,7 +5232,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_de > ARCSTAT_INCR(arcstat_l2_write_bytes, write_asize); > ARCSTAT_INCR(arcstat_l2_size, write_sz); > ARCSTAT_INCR(arcstat_l2_asize, write_asize); > - vdev_space_update(dev->l2ad_vdev, write_asize, 0, 0); > + vdev_space_update(dev->l2ad_vdev, write_psize, 0, 0); > > /* > * Bump device hand to the device start if it is approaching the end. > -- Andriy Gapon _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
