GFS2: quota allows exceeding hard limit

Immediately after being synced to disk, cached quotas are zeroed out and a
subsequent access of the cached quotas results in incorrect zero values. This
meant that gfs2 assumed the actual usage to be the zero (or near-zero) usage
values it found in the cached quotas and comparison against warn/limits never
triggered a quota violation.

This patch adds a new flag QDF_REFRESH that is set after a sync so that the
cached quotas are forcefully refreshed from disk on a subsequent access on
seeing this flag set.

Resolves: rhbz#675944
Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 720c1e6..59aaaa0 100644 (file)
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -317,6 +317,7 @@ enum {
        QDF_USER                = 0,
        QDF_CHANGE              = 1,
        QDF_LOCKED              = 2,
+       QDF_REFRESH             = 3,
 };
 
 struct gfs2_quota_data {

diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index 6ec964c..e23d986 100644 (file)
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -834,6 +834,7 @@ static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
                        goto out_end_trans;
 
                do_qc(qd, -qd->qd_change_sync);
+               set_bit(QDF_REFRESH, &qd->qd_flags);
        }
 
        error = 0;
@@ -929,6 +930,7 @@ int gfs2_quota_lock(struct gfs2_inode *ip, u32 uid, u32 gid)
 {
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_alloc *al = ip->i_alloc;
+       struct gfs2_quota_data *qd;
        unsigned int x;
        int error = 0;
 
@@ -942,7 +944,11 @@ int gfs2_quota_lock(struct gfs2_inode *ip, u32 uid, u32 gid)
             sort_qd, NULL);
 
        for (x = 0; x < al->al_qd_num; x++) {
-               error = do_glock(al->al_qd[x], NO_FORCE, &al->al_qd_ghs[x]);
+               int force = NO_FORCE;
+               qd = al->al_qd[x];
+               if (test_and_clear_bit(QDF_REFRESH, &qd->qd_flags))
+                       force = FORCE;
+               error = do_glock(qd, force, &al->al_qd_ghs[x]);
                if (error)
                        break;
        }