Commit 5fcff61e authored by Bob Peterson's avatar Bob Peterson Committed by Andreas Gruenbacher
Browse files

gfs2: use i_lock spin_lock for inode qadata 



Before this patch, functions gfs2_qa_get and _put used the i_rw_mutex to
prevent simultaneous access to its i_qadata. But i_rw_mutex is now used
for many other things, including iomap_begin and end, which causes a
conflict according to lockdep. We cannot just remove the lock since
simultaneous opens (gfs2_open -> gfs2_open_common -> gfs2_qa_get) can
then stomp on each others values for i_qadata.

This patch solves the conflict by using the i_lock spin_lock in the inode
to prevent simultaneous access.

Signed-off-by: default avatarBob Peterson <rpeterso@redhat.com>
Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
parent f4a47561

fs/gfs2/quota.c

+20 −12
Original line number Diff line number Diff line
@@ -528,34 +528,42 @@ static void qdsb_put(struct gfs2_quota_data *qd) 
 */

int gfs2_qa_get(struct gfs2_inode *ip)

{

	int error = 0;

	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

	struct inode *inode = &ip->i_inode;



	if (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF)

		return 0;



	down_write(&ip->i_rw_mutex);

	spin_lock(&inode->i_lock);

	if (ip->i_qadata == NULL) {

		ip->i_qadata = kmem_cache_zalloc(gfs2_qadata_cachep, GFP_NOFS);

		if (!ip->i_qadata) {

			error = -ENOMEM;

			goto out;

		}

		struct gfs2_qadata *tmp;



		spin_unlock(&inode->i_lock);

		tmp = kmem_cache_zalloc(gfs2_qadata_cachep, GFP_NOFS);

		if (!tmp)

			return -ENOMEM;



		spin_lock(&inode->i_lock);

		if (ip->i_qadata == NULL)

			ip->i_qadata = tmp;

		else

			kmem_cache_free(gfs2_qadata_cachep, tmp);

	}

	ip->i_qadata->qa_ref++;

out:

	up_write(&ip->i_rw_mutex);

	return error;

	spin_unlock(&inode->i_lock);

	return 0;

}



void gfs2_qa_put(struct gfs2_inode *ip)

{

	down_write(&ip->i_rw_mutex);

	struct inode *inode = &ip->i_inode;



	spin_lock(&inode->i_lock);

	if (ip->i_qadata && --ip->i_qadata->qa_ref == 0) {

		kmem_cache_free(gfs2_qadata_cachep, ip->i_qadata);

		ip->i_qadata = NULL;

	}

	up_write(&ip->i_rw_mutex);

	spin_unlock(&inode->i_lock);

}



int gfs2_quota_hold(struct gfs2_inode *ip, kuid_t uid, kgid_t gid)