Currently we dropped freeze protection of aio writes just after IO was submitted. Thus aio write could be in flight while the filesystem was frozen and that could result in unexpected situation like aio completion wanting to convert extent type on frozen filesystem. Testcase from Dmitry triggering this is like: for ((i=0;i<60;i++));do fsfreeze -f /mnt ;sleep 1;fsfreeze -u /mnt;done & fio --bs=4k --ioengine=libaio --iodepth=128 --size=1g --direct=1 \ --runtime=60 --filename=/mnt/file --name=rand-write --rw=randwrite Fix the problem by dropping freeze protection only once IO is completed in aio_complete().
Unified · Split
| @@ -1078,6 +1078,17 @@ static void aio_complete(struct kiocb *kiocb, long res, long res2) · 1077 unmodified lines | |||
| 1078 | unsigned tail, pos, head; | 1078 | unsigned tail, pos, head; |
| 1079 | unsigned long flags; | 1079 | unsigned long flags; |
| 1080 | 1080 | ||
| 1081 | if (kiocb->ki_flags & IOCB_WRITE) { | ||
| 1082 | struct file *file = kiocb->ki_filp; | ||
| 1083 | |||
| 1084 | /* | ||
| 1085 | * Tell lockdep we inherited freeze protection from submission | ||
| 1086 | * thread. | ||
| 1087 | */ | ||
| 1088 | __sb_writers_acquired(file_inode(file)->i_sb, SB_FREEZE_WRITE); | ||
| 1089 | file_end_write(file); | ||
| 1090 | } | ||
| 1091 | |||
| 1081 | /* | 1092 | /* |
| 1082 | * Special case handling for sync iocbs: | 1093 | * Special case handling for sync iocbs: |
| 1083 | * - events go directly into the iocb for fast handling | 1094 | * - events go directly into the iocb for fast handling |
| @@ -1473,9 +1484,15 @@ static ssize_t aio_write(struct kiocb *req, struct iocb *iocb, bool vectored, · 389 unmodified lines | |||
| 1473 | return ret; | 1484 | return ret; |
| 1474 | ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter)); | 1485 | ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter)); |
| 1475 | if (!ret) { | 1486 | if (!ret) { |
| 1487 | req->ki_flags |= IOCB_WRITE; | ||
| 1476 | file_start_write(file); | 1488 | file_start_write(file); |
| 1477 | ret = aio_ret(req, file->f_op->write_iter(req, &iter)); | 1489 | ret = aio_ret(req, file->f_op->write_iter(req, &iter)); |
| 1478 | file_end_write(file); | 1490 | /* |
| 1491 | * We release freeze protection in aio_complete(). Fool lockdep | ||
| 1492 | * by telling it the lock got released so that it doesn't | ||
| 1493 | * complain about held lock when we return to userspace. | ||
| 1494 | */ | ||
| 1495 | __sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE); | ||
| 1479 | } | 1496 | } |
| 1480 | kfree(iovec); | 1497 | kfree(iovec); |
| 1481 | return ret; | 1498 | return ret; |
| @@ -321,6 +321,7 @@ struct writeback_control; · 320 unmodified lines | |||
| 321 | #define IOCB_HIPRI (1 << 3) | 321 | #define IOCB_HIPRI (1 << 3) |
| 322 | #define IOCB_DSYNC (1 << 4) | 322 | #define IOCB_DSYNC (1 << 4) |
| 323 | #define IOCB_SYNC (1 << 5) | 323 | #define IOCB_SYNC (1 << 5) |
| 324 | #define IOCB_WRITE (1 << 6) | ||
| 324 | 325 | ||
| 325 | struct kiocb { | 326 | struct kiocb { |
| 326 | struct file *ki_filp; | 327 | struct file *ki_filp; |