On Fri, Aug 23, 2024 at 12:48 AM Raul Rangel <rrangel@xxxxxxxxxxxx> wrote: > > Hello, > We recently upgraded our kernel on our build bots from 6.5.0-45 to > 6.8.0-40. During this upgrade we started getting failing with the > following error: > > overlay: too many lower directories, limit is 500 Hi Raul, This regression was already reported and a patch to fix it was submitted: https://lore.kernel.org/linux-unionfs/20240705011510.794025-3-chengzhihao1@xxxxxxxxxx/ However, both me and Miklos were away for a while, so nobody picked it up. I have now asked Christian to apply the fixes via his vfs tree. After it gets merged to the upstream kernel, it should be picked up to the actively maintained LTS trees. Thanks, Amir. > > When we need to mount 500+ layers, we create n/500 overlay mounts each > with 500 lowerdirs, we then use those n/500 layers as the lowerdirs to > another overlayfs mount. > > I wrote a little script that can reproduce it: https://paste.myconan.net/501972 > > If I invoke it with `unshare -mr ~/tmp/overlay-test 500 100` it fails, > but if I invoke it with `unshare -mr ~/tmp/overlay-test 499 100` it > works. > > Essentially the following command fails: > > mount -t overlay overlay -o lowerdir=1:2:3:4:5:6:7:8:9:10:11:12:13:14:15:16:17:18:19:20:21:22:23:24:25:26:27:28:29:30:31:32:33:34:35:36:37:38:39:40:41:42:43:44:45:46:47:48:49:50:51:52:53:54:55:56:57:58:59:60:61:62:63:64:65:66:67:68:69:70:71:72:73:74:75:76:77:78:79:80:81:82:83:84:85:86:87:88:89:90:91:92:93:94:95:96:97:98:99:100:101:102:103:104:105:106:107:108:109:110:111:112:113:114:115:116:117:118:119:120:121:122:123:124:125:126:127:128:129:130:131:132:133:134:135:136:137:138:139:140:141:142:143:144:145:146:147:148:149:150:151:152:153:154:155:156:157:158:159:160:161:162:163:164:165:166:167:168:169:170:171:172:173:174:175:176:177:178:179:180:181:182:183:184:185:186:187:188:189:190:191:192:193:194:195:196:197:198:199:200:201:202:203:204:205:206:207:208:209:210:211:212:213:214:215:216:217:218:219:220:221:222:223:224:225:226:227:228:229:230:231:232:233:234:235:236:237:238:239:240:241:242:243:244:245:246:247:248:249:250:251:252:253:254:255:256:257:258:259:260:261:262:263:264:265:266:267:268:269:270:271:272:273:274:275:276:277:278:279:280:281:282:283:284:285:286:287:288:289:290:291:292:293:294:295:296:297:298:299:300:301:302:303:304:305:306:307:308:309:310:311:312:313:314:315:316:317:318:319:320:321:322:323:324:325:326:327:328:329:330:331:332:333:334:335:336:337:338:339:340:341:342:343:344:345:346:347:348:349:350:351:352:353:354:355:356:357:358:359:360:361:362:363:364:365:366:367:368:369:370:371:372:373:374:375:376:377:378:379:380:381:382:383:384:385:386:387:388:389:390:391:392:393:394:395:396:397:398:399:400:401:402:403:404:405:406:407:408:409:410:411:412:413:414:415:416:417:418:419:420:421:422:423:424:425:426:427:428:429:430:431:432:433:434:435:436:437:438:439:440:441:442:443:444:445:446:447:448:449:450:451:452:453:454:455:456:457:458:459:460:461:462:463:464:465:466:467:468:469:470:471:472:473:474:475:476:477:478:479:480:481:482:483:484:485:486:487:488:489:490:491:492:493:494:495:496:497:498:499:500 ../../merged/0 > > but this one succeeds (notice I dropped 500): > > mount -t overlay overlay -o lowerdir=1:2:3:4:5:6:7:8:9:10:11:12:13:14:15:16:17:18:19:20:21:22:23:24:25:26:27:28:29:30:31:32:33:34:35:36:37:38:39:40:41:42:43:44:45:46:47:48:49:50:51:52:53:54:55:56:57:58:59:60:61:62:63:64:65:66:67:68:69:70:71:72:73:74:75:76:77:78:79:80:81:82:83:84:85:86:87:88:89:90:91:92:93:94:95:96:97:98:99:100:101:102:103:104:105:106:107:108:109:110:111:112:113:114:115:116:117:118:119:120:121:122:123:124:125:126:127:128:129:130:131:132:133:134:135:136:137:138:139:140:141:142:143:144:145:146:147:148:149:150:151:152:153:154:155:156:157:158:159:160:161:162:163:164:165:166:167:168:169:170:171:172:173:174:175:176:177:178:179:180:181:182:183:184:185:186:187:188:189:190:191:192:193:194:195:196:197:198:199:200:201:202:203:204:205:206:207:208:209:210:211:212:213:214:215:216:217:218:219:220:221:222:223:224:225:226:227:228:229:230:231:232:233:234:235:236:237:238:239:240:241:242:243:244:245:246:247:248:249:250:251:252:253:254:255:256:257:258:259:260:261:262:263:264:265:266:267:268:269:270:271:272:273:274:275:276:277:278:279:280:281:282:283:284:285:286:287:288:289:290:291:292:293:294:295:296:297:298:299:300:301:302:303:304:305:306:307:308:309:310:311:312:313:314:315:316:317:318:319:320:321:322:323:324:325:326:327:328:329:330:331:332:333:334:335:336:337:338:339:340:341:342:343:344:345:346:347:348:349:350:351:352:353:354:355:356:357:358:359:360:361:362:363:364:365:366:367:368:369:370:371:372:373:374:375:376:377:378:379:380:381:382:383:384:385:386:387:388:389:390:391:392:393:394:395:396:397:398:399:400:401:402:403:404:405:406:407:408:409:410:411:412:413:414:415:416:417:418:419:420:421:422:423:424:425:426:427:428:429:430:431:432:433:434:435:436:437:438:439:440:441:442:443:444:445:446:447:448:449:450:451:452:453:454:455:456:457:458:459:460:461:462:463:464:465:466:467:468:469:470:471:472:473:474:475:476:477:478:479:480:481:482:483:484:485:486:487:488:489:490:491:492:493:494:495:496:497:498:499 ../../merged/0 > > Could there be a regression in the 6.8 kernel? > > Thanks, > Raul
