Theodore Ts'o wrote: > Add an ext3 bug-for-bug compatible analogue for data=ordered mode. In > this mode, we force all delayed allocation blocks involved with the > to-be-commited transaction to be allocated, and then flushed out to > disk before the transaction is commited. > > Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx> Haven't really looked into the cause yet but I was playing with this, and ran: # rm -f bigfile smallfile; dd if=/dev/zero of=bigfile bs=1M count=8192; echo boo > smallfile; time /root/fsync smallfile; time /root/fsync bigfile which resulted in: BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 IP: [<ffffffffa02a6de1>] alloc_on_commit_callback+0x27/0x7f [ext4] PGD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/pci0000:00/0000:00:0c.0/0000:02:00.0/irq CPU 1 Modules linked in: ext4 jbd2 crc16 ipt_MASQUERADE iptable_nat nf_nat bridge stp llc autofs4 sunrpc ipv6 cpufreq_ondemand powernow_k8 freq_table xfs exportfs video output sbs sbshc parport_pc lp parport tg3 serio_raw pata_amd k8temp hwmon pata_acpi ata_generic i2c_nforce2 i2c_core pcspkr qla2xxx scsi_transport_fc scsi_tgt shpchp mptspi mptscsih mptbase scsi_transport_spi [last unloaded: ext4] Pid: 5011, comm: kjournald2 Not tainted 2.6.29-rc8 #3 ProLiant DL145 G2 RIP: 0010:[<ffffffffa02a6de1>] [<ffffffffa02a6de1>] alloc_on_commit_callback+0x27/0x7f [ext4] RSP: 0018:ffff88013c847d20 EFLAGS: 00010246 RAX: 000000000000025f RBX: 0000000000000000 RCX: 0000000000000001 RDX: 000000000000025f RSI: ffff88013ec91d00 RDI: ffff880137cedb8c RBP: ffff88013c847d50 R08: ffff880000011580 R09: ffffffff81029cc2 R10: ffff880131744448 R11: ffff88010fd28070 R12: ffff880137ced824 R13: ffff880137ced800 R14: ffff880137cedb8c R15: 0000000000000000 FS: 00007fd21065b6e0(0000) GS:ffff88013fc01f80(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000060 CR3: 0000000000201000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process kjournald2 (pid: 5011, threadinfo ffff88013c846000, task ffff880131744410) Stack: 0000000000006449 0000000000000000 ffff880137ced824 ffff8800bf426230 ffff880137ced800 ffff88013ec91d00 ffff88013c847ea0 ffffffffa00e2024 ffff88013c847dc0 ffff8801199001c0 ffffffff815013a0 000017594c782cbd Call Trace: [<ffffffffa00e2024>] jbd2_journal_commit_transaction+0xff7/0x105b [jbd2] [<ffffffffa00e597e>] kjournald2+0xe6/0x235 [jbd2] [<ffffffff8105b4f7>] ? autoremove_wake_function+0x0/0x38 [<ffffffffa00e5898>] ? kjournald2+0x0/0x235 [jbd2] [<ffffffff8105b389>] kthread+0x49/0x78 [<ffffffff8101251a>] child_rip+0xa/0x20 [<ffffffff81029cc2>] ? native_load_tls+0xf/0x29 [<ffffffff8105b340>] ? kthread+0x0/0x78 [<ffffffff81012510>] ? child_rip+0x0/0x20 Code: 41 5d c9 c3 55 48 89 e5 41 57 41 56 4c 8d b7 8c 03 00 00 41 55 49 89 fd 41 54 53 48 83 ec 08 4c 8b 7f 48 4c 89 f7 e8 84 ee 0a e1 <49> 8b 5f 60 48 83 eb 10 4c 8b 63 10 eb 1f e8 39 36 d8 e0 90 48 RIP [<ffffffffa02a6de1>] alloc_on_commit_callback+0x27/0x7f [ext4] RSP <ffff88013c847d20> CR2: 0000000000000060 ---[ end trace 7c7cc83cb0a81eef ]--- -- 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
