+ mutex_unlock(&sdp->sd_quota_mutex);
+}
+
+/**
+ * gfs2_adjust_quota
+ *
+ * This function was mostly borrowed from gfs2_block_truncate_page which was
+ * in turn mostly borrowed from ext3
+ */
+static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
+ int64_t change, struct gfs2_quota_data *qd)
+{
+ struct inode *inode = ip->i_vnode;
+ struct address_space *mapping = inode->i_mapping;
+ unsigned long index = loc >> PAGE_CACHE_SHIFT;
+ unsigned offset = loc & (PAGE_CACHE_SHIFT - 1);
+ unsigned blocksize, iblock, pos;
+ struct buffer_head *bh;
+ struct page *page;
+ void *kaddr;
+ __be64 *ptr;
+ u64 value;
+ int err = -EIO;
+
+ page = grab_cache_page(mapping, index);
+ if (!page)
+ return -ENOMEM;
+
+ blocksize = inode->i_sb->s_blocksize;
+ iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
+
+ if (!page_has_buffers(page))
+ create_empty_buffers(page, blocksize, 0);
+
+ bh = page_buffers(page);
+ pos = blocksize;
+ while (offset >= pos) {
+ bh = bh->b_this_page;
+ iblock++;
+ pos += blocksize;
+ }
+
+ if (!buffer_mapped(bh)) {
+ gfs2_get_block(inode, iblock, bh, 1);
+ if (!buffer_mapped(bh))
+ goto unlock;
+ }
+
+ if (PageUptodate(page))
+ set_buffer_uptodate(bh);
+
+ if (!buffer_uptodate(bh)) {
+ ll_rw_block(READ, 1, &bh);
+ wait_on_buffer(bh);
+ if (!buffer_uptodate(bh))
+ goto unlock;
+ }
+
+ gfs2_trans_add_bh(ip->i_gl, bh, 0);
+
+ kaddr = kmap_atomic(page, KM_USER0);
+ ptr = (__be64 *)(kaddr + offset);
+ value = *ptr = cpu_to_be64(be64_to_cpu(*ptr) + change);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ err = 0;
+ qd->qd_qb.qb_magic = cpu_to_be32(GFS2_MAGIC);
+#if 0
+ qd->qd_qb.qb_limit = cpu_to_be64(q.qu_limit);
+ qd->qd_qb.qb_warn = cpu_to_be64(q.qu_warn);
+#endif
+ qd->qd_qb.qb_value = cpu_to_be64(value);
+unlock:
+ unlock_page(page);
+ page_cache_release(page);
+ return err;