FYI, we noticed the following commit (built with gcc-7): commit: 7eafb77890ff459863e3bc772465cb641c14f754 ("btrfs: Do super block verification before writing it to disk") https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master in testcase: fsmark with following parameters: iterations: 1x nr_threads: 1t disk: 1BRD_32G fs: btrfs fs2: nfsv4 filesize: 4K test_size: 4G sync_method: fsyncBeforeClose nr_files_per_directory: 1fpd cpufreq_governor: performance test-description: The fsmark is a file system benchmark to test synchronous write workloads, for example, mail servers workload. test-url: https://sourceforge.net/projects/fsmark/ on test machine: 88 threads Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz with 64G memory caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): [ 128.496659] ------------[ cut here ]------------ [ 128.502439] BTRFS: Transaction aborted (error -117) [ 128.508652] WARNING: U: 21 PID: 1581 at fs/btrfs/tree-log.c:3101 btrfs_sync_log+0x9c4/0xbe0 [btrfs] [ 128.521041] Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver nfsd auth_rpcgss dm_mod brd btrfs xor zstd_decompress zstd_compress xxhash raid6_pq sd_mod sg intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul crc32c_intel mgag200 ghash_clmulni_intel snd_pcm ttm snd_timer pcbc drm_kms_helper ipmi_si mxm_wmi snd syscopyarea aesni_intel ipmi_devintf sysfillrect soundcore crypto_simd sysimgblt ahci fb_sys_fops glue_helper cryptd libahci drm ipmi_msghandler pcspkr libata shpchp wmi acpi_power_meter acpi_pad ip_tables [ 128.581706] CPU: 21 PID: 1581 Comm: nfsd Not tainted 4.16.0-rc7-00174-g7eafb77 #1 [ 128.590723] Hardware name: Intel Corporation S2600KPR/S2600KPR, BIOS SE5C610.86B.01.01.0019.101220160604 10/12/2016 [ 128.602982] RIP: 0010:btrfs_sync_log+0x9c4/0xbe0 [btrfs] [ 128.609603] RSP: 0018:ffffc90008903ad0 EFLAGS: 00010282 [ 128.616053] RAX: 0000000000000027 RBX: ffff881037f0c800 RCX: 0000000000000000 [ 128.624712] RDX: ffff88085f75ed00 RSI: ffff88085f756918 RDI: ffff88085f756918 [ 128.633366] RBP: ffffc90008903bb0 R08: 0000000000000807 R09: 0000000000aaaaaa [ 128.641948] R10: ffffc90008903a00 R11: ffff88085a4c2ec0 R12: ffff881074934000 [ 128.650601] R13: 00000000ffffff8b R14: ffff88107a630000 R15: ffff881074933800 [ 128.659213] FS: 0000000000000000(0000) GS:ffff88085f740000(0000) knlGS:0000000000000000 [ 128.668879] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 128.675904] CR2: 00007f4a6a747660 CR3: 000000107f20a001 CR4: 00000000003606e0 [ 128.684570] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 128.693185] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 128.701795] Call Trace: [ 128.705166] ? btrfs_sync_file+0x2f3/0x3f0 [btrfs] [ 128.711151] btrfs_sync_file+0x2f3/0x3f0 [btrfs] [ 128.716910] btrfs_file_write_iter+0x440/0x550 [btrfs] [ 128.723284] do_iter_readv_writev+0x116/0x170 [ 128.728753] do_iter_write+0x80/0x190 [ 128.733487] nfsd_vfs_write+0xaf/0x370 [nfsd] [ 128.738885] nfsd4_write+0x179/0x1c0 [nfsd] [ 128.744121] nfsd4_proc_compound+0x3f1/0x640 [nfsd] [ 128.750123] nfsd_dispatch+0xf5/0x230 [nfsd] [ 128.755499] svc_process_common+0x496/0x680 [ 128.760732] ? nfsd_destroy+0x60/0x60 [nfsd] [ 128.765996] svc_process+0xed/0x1b0 [ 128.770499] nfsd+0xf1/0x160 [nfsd] [ 128.774899] kthread+0x11e/0x140 [ 128.778988] ? kthread_associate_blkcg+0xb0/0xb0 [ 128.784679] ret_from_fork+0x35/0x40 [ 128.789187] Code: 00 00 48 8b 42 50 f0 48 0f ba a8 e8 cd 00 00 02 72 1b 41 83 fd fb 0f 84 6f 01 00 00 44 89 ee 48 c7 c7 40 ec 76 a0 e8 3c f1 95 e0 <0f> 0b 48 8b bd 60 ff ff ff 44 89 e9 ba 1d 0c 00 00 48 c7 c6 20 [ 128.811411] ---[ end trace 6c998d6c6547e8f7 ]--- [ 128.817132] BTRFS: error (device ram0) in btrfs_sync_log:3101: errno=-117 unknown [ 128.826014] BTRFS info (device ram0): forced readonly [ 128.835886] fs_mark: fsync failed Input/output error 2018-04-19 17:23:24 fs_mark -d /nfs/ram0/1 -D 1000000 -N 1 -n 1000000 -L 1 -S 1 -s 4096 # fs_mark -d /nfs/ram0/1 -D 1000000 -N 1 -n 1000000 -L 1 -S 1 -s 4096 # Version 3.3, 1 thread(s) starting at Thu Apr 19 17:23:25 2018 # Sync method: INBAND FSYNC: fsync() per file in write loop. # Directories: Round Robin between directories across 1000000 subdirectories with 1 files per subdirectory. # File names: 40 bytes long, (16 initial bytes of time stamp with 24 random bytes at end of name) # Files info: size 4096 bytes, written with an IO size of 16384 bytes per write # App overhead is time in microseconds spent in the test not doing file writing related system calls. FSUse% Count Size Files/sec App Overhead To reproduce: git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp install job.yaml # job file is attached in this email bin/lkp run job.yaml Thanks, Xiaolong