GFS2: Clean up gfs2_adjust_quota() and do_glock()

Both of these functions contained confusing and in one case
duplicate code. This patch adds a new check in do_glock()
so that we report -ENOENT if we are asked to sync a quota
entry which doesn't exist. Due to the previous patch this is
now reported correctly to userspace.

Also there are a few new comments, and I hope that the code
is easier to understand now.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index db124af..33e369f 100644 (file)
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -15,7 +15,7 @@
  * fuzziness in the current usage value of IDs that are being used on different
  * nodes in the cluster simultaneously.  So, it is possible for a user on
  * multiple nodes to overrun their quota, but that overrun is controlable.
- * Since quota tags are part of transactions, there is no need to a quota check
+ * Since quota tags are part of transactions, there is no need for a quota check
  * program to be run on node crashes or anything like that.
  *
  * There are couple of knobs that let the administrator manage the quota
@@ -66,13 +66,6 @@
 #define QUOTA_USER 1
 #define QUOTA_GROUP 0
 
-struct gfs2_quota_host {
-       u64 qu_limit;
-       u64 qu_warn;
-       s64 qu_value;
-       u32 qu_ll_next;
-};
-
 struct gfs2_quota_change_host {
        u64 qc_change;
        u32 qc_flags; /* GFS2_QCF_... */
@@ -618,33 +611,19 @@ static void do_qc(struct gfs2_quota_data *qd, s64 change)
        mutex_unlock(&sdp->sd_quota_mutex);
 }
 
-static void gfs2_quota_in(struct gfs2_quota_host *qu, const void *buf)
-{
-       const struct gfs2_quota *str = buf;
-
-       qu->qu_limit = be64_to_cpu(str->qu_limit);
-       qu->qu_warn = be64_to_cpu(str->qu_warn);
-       qu->qu_value = be64_to_cpu(str->qu_value);
-       qu->qu_ll_next = be32_to_cpu(str->qu_ll_next);
-}
-
-static void gfs2_quota_out(const struct gfs2_quota_host *qu, void *buf)
-{
-       struct gfs2_quota *str = buf;
-
-       str->qu_limit = cpu_to_be64(qu->qu_limit);
-       str->qu_warn = cpu_to_be64(qu->qu_warn);
-       str->qu_value = cpu_to_be64(qu->qu_value);
-       str->qu_ll_next = cpu_to_be32(qu->qu_ll_next);
-       memset(&str->qu_reserved, 0, sizeof(str->qu_reserved));
-}
-
 /**
- * gfs2_adjust_quota
+ * gfs2_adjust_quota - adjust record of current block usage
+ * @ip: The quota inode
+ * @loc: Offset of the entry in the quota file
+ * @change: The amount of change to record
+ * @qd: The quota data
  *
  * This function was mostly borrowed from gfs2_block_truncate_page which was
  * in turn mostly borrowed from ext3
+ *
+ * Returns: 0 or -ve on error
  */
+
 static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
                             s64 change, struct gfs2_quota_data *qd)
 {
@@ -656,8 +635,7 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
        struct buffer_head *bh;
        struct page *page;
        void *kaddr;
-       char *ptr;
-       struct gfs2_quota_host qp;
+       struct gfs2_quota *qp;
        s64 value;
        int err = -EIO;
 
@@ -701,18 +679,13 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
        gfs2_trans_add_bh(ip->i_gl, bh, 0);
 
        kaddr = kmap_atomic(page, KM_USER0);
-       ptr = kaddr + offset;
-       gfs2_quota_in(&qp, ptr);
-       qp.qu_value += change;
-       value = qp.qu_value;
-       gfs2_quota_out(&qp, ptr);
+       qp = kaddr + offset;
+       value = (s64)be64_to_cpu(qp->qu_value) + change;
+       qp->qu_value = cpu_to_be64(value);
+       qd->qd_qb.qb_value = qp->qu_value;
        flush_dcache_page(page);
        kunmap_atomic(kaddr, KM_USER0);
        err = 0;
-       qd->qd_qb.qb_magic = cpu_to_be32(GFS2_MAGIC);
-       qd->qd_qb.qb_value = cpu_to_be64(value);
-       ((struct gfs2_quota_lvb*)(qd->qd_gl->gl_lvb))->qb_magic = cpu_to_be32(GFS2_MAGIC);
-       ((struct gfs2_quota_lvb*)(qd->qd_gl->gl_lvb))->qb_value = cpu_to_be64(value);
 unlock:
        unlock_page(page);
        page_cache_release(page);
@@ -741,8 +714,7 @@ static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
 
        sort(qda, num_qd, sizeof(struct gfs2_quota_data *), sort_qd, NULL);
        for (qx = 0; qx < num_qd; qx++) {
-               error = gfs2_glock_nq_init(qda[qx]->qd_gl,
-                                          LM_ST_EXCLUSIVE,
+               error = gfs2_glock_nq_init(qda[qx]->qd_gl, LM_ST_EXCLUSIVE,
                                           GL_NOCACHE, &ghs[qx]);
                if (error)
                        goto out;
@@ -797,8 +769,7 @@ static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
                qd = qda[x];
                offset = qd2offset(qd);
                error = gfs2_adjust_quota(ip, offset, qd->qd_change_sync,
-                                         (struct gfs2_quota_data *)
-                                         qd);
+                                         (struct gfs2_quota_data *)qd);
                if (error)
                        goto out_end_trans;
 
@@ -829,8 +800,7 @@ static int do_glock(struct gfs2_quota_data *qd, int force_refresh,
        struct gfs2_sbd *sdp = qd->qd_gl->gl_sbd;
        struct gfs2_inode *ip = GFS2_I(sdp->sd_quota_inode);
        struct gfs2_holder i_gh;
-       struct gfs2_quota_host q;
-       char buf[sizeof(struct gfs2_quota)];
+       struct gfs2_quota q;
        int error;
        struct gfs2_quota_lvb *qlvb;
 
@@ -853,22 +823,23 @@ restart:
                if (error)
                        goto fail;
 
-               memset(buf, 0, sizeof(struct gfs2_quota));
+               memset(&q, 0, sizeof(struct gfs2_quota));
                pos = qd2offset(qd);
-               error = gfs2_internal_read(ip, NULL, buf, &pos,
-                                          sizeof(struct gfs2_quota));
+               error = gfs2_internal_read(ip, NULL, (char *)&q, &pos, sizeof(q));
                if (error < 0)
                        goto fail_gunlock;
-
+               if ((error < sizeof(q)) && force_refresh) {
+                       error = -ENOENT;
+                       goto fail_gunlock;
+               }
                gfs2_glock_dq_uninit(&i_gh);
 
-               gfs2_quota_in(&q, buf);
                qlvb = (struct gfs2_quota_lvb *)qd->qd_gl->gl_lvb;
                qlvb->qb_magic = cpu_to_be32(GFS2_MAGIC);
                qlvb->__pad = 0;
-               qlvb->qb_limit = cpu_to_be64(q.qu_limit);
-               qlvb->qb_warn = cpu_to_be64(q.qu_warn);
-               qlvb->qb_value = cpu_to_be64(q.qu_value);
+               qlvb->qb_limit = q.qu_limit;
+               qlvb->qb_warn = q.qu_warn;
+               qlvb->qb_value = q.qu_value;
                qd->qd_qb = *qlvb;
 
                gfs2_glock_dq_uninit(q_gh);
@@ -1126,7 +1097,6 @@ int gfs2_quota_refresh(struct gfs2_sbd *sdp, int user, u32 id)
                gfs2_glock_dq_uninit(&q_gh);
 
        qd_put(qd);
-
        return error;
 }