Hi all, This bug has been confirmed by Ted and Lukas. When we run xfstests #083 in a ext4 file system with bigalloc feature, it will be blocked for more than 120s. I hit this bug in 3.8 kernel, and I can confirm that it doesn't be fixed in dev branch until now. This bug is very hard to be hitted in my sand box. I need to run the following commands to trigger it. for i in {0..9} do ./check 083 done My sand box is a Dell Desktop with a Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz, 4G memory, a 160G HDD and a Intel SSD. The test runs against SSD. In 3.8 kernel, we will get the follwing messages from dmesg, and will be blocked for more than 120s: Mar 7 15:15:17 lz-desktop wenqing: run xfstest 083 Mar 7 15:15:17 lz-desktop kernel: EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: acl,user_xattr Mar 7 15:15:18 lz-desktop kernel: EXT4-fs (sda2): delayed block allocation failed for inode 32 at logical offset 631 with max blocks 29 with error -28 Mar 7 15:15:18 lz-desktop kernel: EXT4-fs (sda2): This should not happen!! Data will be lost Mar 7 15:15:18 lz-desktop kernel: Mar 7 15:15:18 lz-desktop kernel: EXT4-fs (sda2): Total free blocks count 288 Mar 7 15:15:18 lz-desktop kernel: EXT4-fs (sda2): Free/Dirty block details Mar 7 15:15:18 lz-desktop kernel: EXT4-fs (sda2): free_blocks=288 Mar 7 15:15:18 lz-desktop kernel: EXT4-fs (sda2): dirty_blocks=96 Mar 7 15:15:18 lz-desktop kernel: EXT4-fs (sda2): Block reservation details Mar 7 15:15:18 lz-desktop kernel: EXT4-fs (sda2): i_reserved_data_blocks=3 Mar 7 15:15:18 lz-desktop kernel: EXT4-fs (sda2): i_reserved_meta_blocks=3 These messages *disappears* in dev branch because Lukas's patches. But we still are blocked for more than 120s as below (after running 9 times): wenqing: run xfstest 083 kernel: EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: acl, user_xattr kernel: INFO: task fsstress:9190 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000000 0 9190 9189 0x00000000 kernel: ffff88010878dd58 0000000000000086 ffff880102928230 ffff88010878c010 kernel: ffff880110d526f0 0000000000012080 ffff88010878dfd8 0000000000004000 kernel: ffff88010878dfd8 0000000000012080 ffffffff82613410 ffff880110d526f0 kernel: Call Trace: kernel: [<ffffffff8205c88d>] ? sched_clock_local+0x1c/0x82 kernel: [<ffffffff8205e797>] ? enqueue_task_fair+0x14a/0x16c kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8205c547>] ? ttwu_do_activate.clone.0+0x3f/0x44 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b kernel: INFO: task fsstress:9191 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000001 0 9191 9189 0x00000000 kernel: ffff880102db3d58 0000000000000086 ffff88011238ad18 ffff880102db2010 kernel: ffff880112d3a6f0 0000000000012080 ffff880102db3fd8 0000000000004000 kernel: ffff880102db3fd8 0000000000012080 ffff880112c84670 ffff880112d3a6f0 kernel: Call Trace: kernel: [<ffffffff8205c88d>] ? sched_clock_local+0x1c/0x82 kernel: [<ffffffff8205da55>] ? check_preempt_wakeup+0x11a/0x1b6 kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8205c547>] ? ttwu_do_activate.clone.0+0x3f/0x44 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b kernel: INFO: task fsstress:9192 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000000 0 9192 9189 0x00000000 kernel: ffff880112317d58 0000000000000086 0000000000000000 ffff880112316010 kernel: ffff880112c1b950 0000000000012080 ffff880112317fd8 0000000000004000 kernel: ffff880112317fd8 0000000000012080 ffff880112c5ad50 ffff880112c1b950 kernel: Call Trace: kernel: [<ffffffff820b02c3>] ? find_get_pages_tag+0xfb/0x130 kernel: [<ffffffff8237ebe7>] ? __schedule+0x740/0x7d2 kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b kernel: INFO: task fsstress:9193 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000000 0 9193 9189 0x00000000 kernel: ffff8801122f7d58 0000000000000082 ffffffffa01f5eea ffff8801122f6010 kernel: ffff8801128492b0 0000000000012080 ffff8801122f7fd8 0000000000004000 kernel: ffff8801122f7fd8 0000000000012080 ffffffff82613410 ffff8801128492b0 kernel: Call Trace: kernel: [<ffffffffa01f5eea>] ? ext4_release_file+0xb2/0xb2 [ext4] kernel: [<ffffffff821074eb>] ? mntput+0x2a/0x2c kernel: [<ffffffff8205c88d>] ? sched_clock_local+0x1c/0x82 kernel: [<ffffffff8205e797>] ? enqueue_task_fair+0x14a/0x16c kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8205c547>] ? ttwu_do_activate.clone.0+0x3f/0x44 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b kernel: INFO: task fsstress:9194 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000000 0 9194 9189 0x00000000 kernel: ffff88010371bd58 0000000000000086 ffff88011238ad18 ffff88010371a010 kernel: ffff880112c5ad50 0000000000012080 ffff88010371bfd8 0000000000004000 kernel: ffff88010371bfd8 0000000000012080 ffffffff82613410 ffff880112c5ad50 kernel: Call Trace: kernel: [<ffffffff8205c88d>] ? sched_clock_local+0x1c/0x82 kernel: [<ffffffff8205e797>] ? enqueue_task_fair+0x14a/0x16c kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8205c547>] ? ttwu_do_activate.clone.0+0x3f/0x44 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b kernel: INFO: task fsstress:9195 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000001 0 9195 9189 0x00000000 kernel: ffff8801036f3d58 0000000000000086 ffff88011238ad18 ffff8801036f2010 kernel: ffff880112c912f0 0000000000012080 ffff8801036f3fd8 0000000000004000 kernel: ffff8801036f3fd8 0000000000012080 ffff88011331d950 ffff880112c912f0 kernel: Call Trace: kernel: [<ffffffff8201e533>] ? native_smp_send_reschedule+0x5c/0x5e kernel: [<ffffffff82055b9e>] ? resched_task+0x61/0x63 kernel: [<ffffffff8205da8f>] ? check_preempt_wakeup+0x154/0x1b6 kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8205c547>] ? ttwu_do_activate.clone.0+0x3f/0x44 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b kernel: INFO: task fsstress:9196 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000000 0 9196 9189 0x00000000 kernel: ffff8801081d9d58 0000000000000082 ffff88011238ad18 ffff8801081d8010 kernel: ffff88011238a6b0 0000000000012080 ffff8801081d9fd8 0000000000004000 kernel: ffff8801081d9fd8 0000000000012080 ffff880112d0a0d0 ffff88011238a6b0 kernel: Call Trace: kernel: [<ffffffff8205c88d>] ? sched_clock_local+0x1c/0x82 kernel: [<ffffffff8205da55>] ? check_preempt_wakeup+0x11a/0x1b6 kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8205c547>] ? ttwu_do_activate.clone.0+0x3f/0x44 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b kernel: INFO: task fsstress:9197 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000001 0 9197 9189 0x00000000 kernel: ffff88011087bd58 0000000000000086 ffff8801110c0800 ffff88011087a010 kernel: ffff880112c84670 0000000000012080 ffff88011087bfd8 0000000000004000 kernel: ffff88011087bfd8 0000000000012080 ffff880112cd4c90 ffff880112c84670 kernel: Call Trace: kernel: [<ffffffff8205c88d>] ? sched_clock_local+0x1c/0x82 kernel: [<ffffffff8205e797>] ? enqueue_task_fair+0x14a/0x16c kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8205c547>] ? ttwu_do_activate.clone.0+0x3f/0x44 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b kernel: INFO: task fsstress:9198 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000000 0 9198 9189 0x00000000 kernel: ffff880110993d58 0000000000000082 ffff88011238ad18 ffff880110992010 kernel: ffff880112c1a0d0 0000000000012080 ffff880110993fd8 0000000000004000 kernel: ffff880110993fd8 0000000000012080 ffff88011238a6b0 ffff880112c1a0d0 kernel: Call Trace: kernel: [<ffffffff820b02c3>] ? find_get_pages_tag+0xfb/0x130 kernel: [<ffffffff8205da8f>] ? check_preempt_wakeup+0x154/0x1b6 kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b kernel: INFO: task fsstress:9199 blocked for more than 120 seconds. kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kernel: fsstress D 0000000000000001 0 9199 9189 0x00000000 kernel: ffff88010365dd58 0000000000000082 ffff880101128170 ffff88010365c010 kernel: ffff880112cec0d0 0000000000012080 ffff88010365dfd8 0000000000004000 kernel: ffff88010365dfd8 0000000000012080 ffff88011331d950 ffff880112cec0d0 kernel: Call Trace: kernel: [<ffffffff8205c88d>] ? sched_clock_local+0x1c/0x82 kernel: [<ffffffff8205e797>] ? enqueue_task_fair+0x14a/0x16c kernel: [<ffffffff8237ef2f>] schedule+0x64/0x66 kernel: [<ffffffff8237d4cc>] schedule_timeout+0x2b/0x178 kernel: [<ffffffff8205c547>] ? ttwu_do_activate.clone.0+0x3f/0x44 kernel: [<ffffffff8237edbc>] wait_for_common+0xbd/0x112 kernel: [<ffffffff8205c76a>] ? try_to_wake_up+0x21e/0x21e kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8237eec9>] wait_for_completion+0x1d/0x1f kernel: [<ffffffff821105c8>] sync_inodes_sb+0xb3/0x198 kernel: [<ffffffff82114559>] ? fdatawrite_one_bdev+0x18/0x18 kernel: [<ffffffff8211456d>] sync_inodes_one_sb+0x14/0x16 kernel: [<ffffffff820f0f0a>] iterate_supers+0x6d/0xbf kernel: [<ffffffff821145a4>] sys_sync+0x35/0x83 kernel: [<ffffffff82386942>] system_call_fastpath+0x16/0x1b Regards, - Zheng -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html