rafaeldtinoco
commented
5 years ago Comment from Cyril in the mailing list:
"""
Right, we expect that the device is free to be reused once the umount() returns to the userspace, which apparently is not true in your case.
Looking into the mkfs code it tries to open() the device RDONLY and we get this error if the attempt has failed with EBUSY, which likely means that the umount() is still running in background in kernel.
I guess that we may as well patch the tst_umount() function in lib/tst_device.c to loop until open() fails with EBUSY in the similar manner we attempt to retry umount() there. """
Apparently, when having "all_filesystems" flag set for one test, there is a room of opportunity for the subsequent filesystems tests to find the device, acquired by "tst_acquire_device()", busy.
I suppose, in the case bellow, fsync() caused async work in some kernel thread to cause the "/dev/loop0 is apparently in use by the system" error when trying a new mkfs.XXXX call - for the subsequent filesystem - using the same acquired device.
With the "all_filesystems" logic, the acquired device is not detached, nor find_free_loopdev() is called again, which could mitigate this.
The error:
tst_test.c:1015: INFO: Timeout per run is 0h 15m 00s fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 tst_test.c:1076: INFO: Testing on ext3 tst_mkfs.c:83: INFO: Formatting /dev/loop0 with ext3 opts='' extra opts='' mke2fs 1.43.5 (04-Aug-2017) [ 48.457646] EXT4-fs (loop0): mounting ext3 file system using the ext4 subsystem [ 48.502872] EXT4-fs (loop0): mounted filesystem with ordered data mode. Opts: (null) tst_test.c:1015: INFO: Timeout per run is 0h 15m 00s fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 fsync01.c:58: PASS: fsync() returned 0 tst_test.c:1076: INFO: Testing on ext4 tst_mkfs.c:83: INFO: Formatting /dev/loop0 with ext4 opts='' extra opts='' mke2fs 1.43.5 (04-Aug-2017) /dev/loop0 is apparently in use by the system; will not make a filesystem here! tst_mkfs.c:94: BROK: mkfs.ext4:1: tst_test.c failed with 729