- if (sbinfo) {
- max_blocks = sbinfo->max_blocks;
- max_inodes = sbinfo->max_inodes;
- }
- if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, &max_inodes))
- return -EINVAL;
- /* Keep it simple: disallow limited <-> unlimited remount */
- if ((max_blocks || max_inodes) == !sbinfo)
- return -EINVAL;
- /* But allow the pointless unlimited -> unlimited remount */
- if (!sbinfo)
- return 0;
- return shmem_set_size(sbinfo, max_blocks, max_inodes);
+ spin_lock(&sbinfo->stat_lock);
+ blocks = sbinfo->max_blocks - sbinfo->free_blocks;
+ inodes = sbinfo->max_inodes - sbinfo->free_inodes;
+ if (max_blocks < blocks)
+ goto out;
+ if (max_inodes < inodes)
+ goto out;
+ /*
+ * Those tests also disallow limited->unlimited while any are in
+ * use, so i_blocks will always be zero when max_blocks is zero;
+ * but we must separately disallow unlimited->limited, because
+ * in that case we have no record of how much is already in use.
+ */
+ if (max_blocks && !sbinfo->max_blocks)
+ goto out;
+ if (max_inodes && !sbinfo->max_inodes)
+ goto out;
+
+ error = 0;
+ sbinfo->max_blocks = max_blocks;
+ sbinfo->free_blocks = max_blocks - blocks;
+ sbinfo->max_inodes = max_inodes;
+ sbinfo->free_inodes = max_inodes - inodes;
+out:
+ spin_unlock(&sbinfo->stat_lock);
+ return error;