Hello Luis Henriques,
This is a semi-automatic email about new static checker warnings.
The patch b7a2921765cf: "ceph: quota: support for
ceph.quota.max_files" from Jan 5, 2018, leads to the following Smatch
complaint:
fs/ceph/quota.c:240 check_quota_exceeded()
error: we previously assumed 'realm' could be null (see line 188)
fs/ceph/quota.c
187 "null i_snap_realm\n", ceph_vinop(inode));
188 while (realm) {
^^^^^
Check for NULL.
189 spin_lock(&realm->inodes_with_caps_lock);
190 in = realm->inode ? igrab(realm->inode) : NULL;
191 spin_unlock(&realm->inodes_with_caps_lock);
192 if (!in)
193 break;
194
195 ci = ceph_inode(in);
196 spin_lock(&ci->i_ceph_lock);
197 if (op == QUOTA_CHECK_MAX_FILES_OP) {
198 max = ci->i_max_files;
199 rvalue = ci->i_rfiles + ci->i_rsubdirs;
200 } else {
201 max = ci->i_max_bytes;
202 rvalue = ci->i_rbytes;
203 }
204 spin_unlock(&ci->i_ceph_lock);
205 switch (op) {
206 case QUOTA_CHECK_MAX_FILES_OP:
207 exceeded = (max && (rvalue >= max));
208 break;
209 case QUOTA_CHECK_MAX_BYTES_OP:
210 exceeded = (max && (rvalue + delta > max));
211 break;
212 case QUOTA_CHECK_MAX_BYTES_APPROACHING_OP:
213 if (max) {
214 if (rvalue >= max)
215 exceeded = true;
216 else {
217 /*
218 * when we're writing more that 1/16th
219 * of the available space
220 */
221 exceeded =
222 (((max - rvalue) >> 4) < delta);
223 }
224 }
225 break;
226 default:
227 /* Shouldn't happen */
228 pr_warn("Invalid quota check op (%d)\n", op);
229 exceeded = true; /* Just break the loop */
230 }
231 iput(in);
232
233 next = realm->parent;
234 if (exceeded || !next)
235 break;
236 ceph_get_snap_realm(mdsc, next);
237 ceph_put_snap_realm(mdsc, realm);
238 realm = next;
239 }
240 ceph_put_snap_realm(mdsc, realm);
^^^^^
Unchecked dereference inside function.
241 up_read(&mdsc->snap_rwsem);
242
regards,
dan carpenter
