Hi Matthew, thanks for your work on this patch series!
I applied it against 4c3, and ran a quick test run on it, and found
the following locking problem. To reproduce:
kvm-xfstests -c nojournal generic/113
generic/113 [09:27:19][ 5.841937] run fstests generic/113 at 2019-10-21 09:27:19
[ 7.959477]
[ 7.959798] ============================================
[ 7.960518] WARNING: possible recursive locking detected
[ 7.961225] 5.4.0-rc3-xfstests-00012-g7fe6ea084e48 #1238 Not tainted
[ 7.961991] --------------------------------------------
[ 7.962569] aio-stress/1516 is trying to acquire lock:
[ 7.963129] ffff9fd4791148c8 (&sb->s_type->i_mutex_key#12){++++}, at: __generic_file_fsync+0x3e/0xb0
[ 7.964109]
[ 7.964109] but task is already holding lock:
[ 7.964740] ffff9fd4791148c8 (&sb->s_type->i_mutex_key#12){++++}, at: ext4_dio_write_iter+0x15b/0x430
[ 7.965763]
[ 7.965763] other info that might help us debug this:
[ 7.966630] Possible unsafe locking scenario:
[ 7.966630]
[ 7.967424] CPU0
[ 7.967760] ----
[ 7.968097] lock(&sb->s_type->i_mutex_key#12);
[ 7.968827] lock(&sb->s_type->i_mutex_key#12);
[ 7.969558]
[ 7.969558] *** DEADLOCK ***
[ 7.969558]
[ 7.970518] May be due to missing lock nesting notation
[ 7.970518]
[ 7.971592] 1 lock held by aio-stress/1516:
[ 7.972267] #0: ffff9fd4791148c8 (&sb->s_type->i_mutex_key#12){++++}, at: ext4_dio_write_iter+0x15b/0x430
[ 7.973807]
[ 7.973807] stack backtrace:
[ 7.974510] CPU: 0 PID: 1516 Comm: aio-stress Not tainted 5.4.0-rc3-xfstests-00012-g7fe6ea084e48 #1238
[ 7.976053] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[ 7.977327] Call Trace:
[ 7.977700] dump_stack+0x67/0x90
[ 7.978198] __lock_acquire.cold+0x130/0x1f7
[ 7.978829] ? __switch_to_asm+0x40/0x70
[ 7.979659] lock_acquire+0x9a/0x160
[ 7.980320] ? __generic_file_fsync+0x3e/0xb0
[ 7.981014] down_write+0x40/0x110
[ 7.981717] ? __generic_file_fsync+0x3e/0xb0
[ 7.982676] __generic_file_fsync+0x3e/0xb0
[ 7.983454] ext4_sync_file+0x277/0x4e0
[ 7.984188] iomap_dio_complete+0x112/0x130
[ 7.984971] ? iomap_dio_rw+0x3a0/0x4b0
[ 7.985647] iomap_dio_rw+0x419/0x4b0
[ 7.986317] ? ext4_dio_write_iter+0x296/0x430
[ 7.987039] ext4_dio_write_iter+0x296/0x430
[ 7.987786] aio_write+0xef/0x1c0
[ 7.988284] ? kvm_sched_clock_read+0x14/0x30
[ 7.988822] ? sched_clock+0x5/0x10
[ 7.989234] ? sched_clock_cpu+0xc/0xc0
[ 7.989719] __io_submit_one.constprop.0+0x399/0x5f0
[ 7.990315] ? kvm_sched_clock_read+0x14/0x30
[ 7.990917] ? sched_clock+0x5/0x10
[ 7.991473] ? sched_clock_cpu+0xc/0xc0
[ 7.992097] ? io_submit_one+0x141/0x5a0
[ 7.992741] io_submit_one+0x141/0x5a0
[ 7.993354] __x64_sys_io_submit+0x9a/0x290
[ 7.993853] ? do_syscall_64+0x50/0x1b0
[ 7.994250] ? __ia32_sys_io_destroy+0x10/0x10
[ 7.994748] do_syscall_64+0x50/0x1b0
[ 7.995175] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 7.995761] RIP: 0033:0x55d1268c2d17
[ 7.996270] Code: 00 75 08 8b 47 0c 39 47 08 74 08 e9 b3 ff ff ff 0f 1f 00 31 c0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 b8 d1 00 00 00 0f 05 <c3> 0f 1f 84 00 00 00 00 00 48 63 ff b8 ce 00 00 00 0f 05 c3 0f 1f
[ 7.999131] RSP: 002b:00007f090fb0bd88 EFLAGS: 00000202 ORIG_RAX: 00000000000000d1
[ 7.999994] RAX: ffffffffffffffda RBX: 000055d128135010 RCX: 000055d1268c2d17
[ 8.000881] RDX: 000055d128135010 RSI: 0000000000000008 RDI: 00007f0907263000
[ 8.001765] RBP: 000055d128129560 R08: 00007fff421ae080 R09: 00007f090fb0bd68
[ 8.002824] R10: 00007f090fb0bd60 R11: 0000000000000202 R12: 0000000000000008
[ 8.004016] R13: 00007f090fb0bdb0 R14: 00007f090fb0bda0 R15: 000055d128129560
I'm other test configurations are still running, and I haven't had a
chance to do a detailed review on it, but I'll try to get to it this
week.
Thanks,
- Ted
