[Cluster-devel] [GFS2 PATCH] GFS2: Check rs_free with rd_rsspin protection
Steven Whitehouse
swhiteho at redhat.com
Wed Jul 6 16:01:25 UTC 2016
Hi,
Acked-by: Steven Whitehouse <swhiteho at redhat.com>
Steve.
On 06/07/16 16:52, Bob Peterson wrote:
> Hi,
>
> For the last process to close a file opened for write, function
> gfs2_rsqa_delete was deleting the file's inode's block reservation
> out of the rgrp reservations tree. Then it was checking to make sure
> rs_free was 0, but it was performing the check outside the protection
> of rd_rsspin spin_lock. The rd_rsspin spin_lock protection is needed
> to prevent a race between the process freeing the reservation and
> another who is allocating a new set of blocks inside the same rgrp
> for the same inode, thus changing its value.
>
> Signed-off-by: Bob Peterson <rpeterso at redhat.com>
>
> Regards,
>
> Bob Peterson
> Red Hat File Systems
> ---
> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
> index fba38ca..86ccc015 100644
> --- a/fs/gfs2/rgrp.c
> +++ b/fs/gfs2/rgrp.c
> @@ -658,6 +658,7 @@ void gfs2_rs_deltree(struct gfs2_blkreserv *rs)
> if (rgd) {
> spin_lock(&rgd->rd_rsspin);
> __rs_deltree(rs);
> + BUG_ON(rs->rs_free);
> spin_unlock(&rgd->rd_rsspin);
> }
> }
> @@ -671,10 +672,8 @@ void gfs2_rs_deltree(struct gfs2_blkreserv *rs)
> void gfs2_rsqa_delete(struct gfs2_inode *ip, atomic_t *wcount)
> {
> down_write(&ip->i_rw_mutex);
> - if ((wcount == NULL) || (atomic_read(wcount) <= 1)) {
> + if ((wcount == NULL) || (atomic_read(wcount) <= 1))
> gfs2_rs_deltree(&ip->i_res);
> - BUG_ON(ip->i_res.rs_free);
> - }
> up_write(&ip->i_rw_mutex);
> gfs2_qa_delete(ip, wcount);
> }
>
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