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Date: Tue, 08 Sep 2009 13:11:48 +0900 From: Akira Fujita <a-fujita@...jp.nec.com> To: Peng Tao <bergwolf@...il.com> CC: Greg Freemyer <greg.freemyer@...il.com>, Theodore Tso <tytso@....edu>, linux-ext4@...r.kernel.org Subject: Re: [PATCH 3/4]ext4: Return exchanged blocks count to user space in failure Hi Peng, Peng Tao wrote: > Hi, Akira, > > Akira Fujita wrote: >> Hi Peng, >> Peng Tao wrote: >>> Hi, Greg, >>> >>> On Thu, Sep 3, 2009 at 4:59 AM, Greg Freemyer<greg.freemyer@...il.com> wrote: >>>> Peng, >>>> >>>> I have not looked at the code very closely, but can you tell me where >>>> a file corruption can take place? Not completing the replacement of >>>> extents with donor extents is one thing. Corrupting the original file >>>> contents is another. >>> The file corruption is mainly because of the half done replacement. >>> >>> My test case is here: >>> http://marc.info/?l=linux-ext4&m=124992522305319&w=2 >>> >> This patch solves your test case problem. >> >>> $dd if=/dev/zero of=zero.img bs=10M count=0 seek=50 >>> $dd if=../609xp.img of=first.img bs=10M count=1 >>> $dd if=/dev/zero of=first.img bs=10M count=0 seek=50 >>> $dd if=../609xp.img of=last.img bs=10M count=1 seek=49 >>> $dd if=../609xp.img of=middle.img bs=10M count=1 seek=24 >>> $dd if=/dev/zero of=middle.img bs=10M count=0 seek=50 >> >> This problem is caused by the fact that logical offset of >> orig file is different from donor file's. >> To detect the logical offset difference in EXT4_IOC_MOVE_EXT, >> add checks to mext_calc_swap_extents() and handles it as error, >> since data exchange must be done between the same blocks. >> >> Note: This problem does not happen in ext4 online defrag >> (means with e4defrag command), because the donor file >> which is created by e4defrag in user space is >> file constitution same as orig file. >> >> And add the extent null check to ext_get_path() for >> followings test case. >>> $dd if=/dev/zero of=zero.img bs=10M count=0 seek=50 >> More test cases are needed for EXT4_IOC_MOVE_EXT, >> so this patch may not be complete, >> but the problem you reported is fixed at least. >> I am now testing EXT4_IOC_MOVE_EXT hard. >> >> BTW, I'm now looking into the empty extent issue which >> you reported, so I will release the patch soon. >> http://marc.info/?l=linux-ext4&m=124975192830024&w=2 >> >> Could you do your test case again with this patch? > After applying the two patches, I run my test case with first.img as the orig file (and middle.img or > last.img as donor file). My kernel panics and I find following message in /var/log/messages after reboot: I could not reproduce this panic. Would you tell me about your test environment (1-5)? 1. What is your kernel version? (2.6.31-rc2 + ext4 patch queue + my patch?) 2. What FS mount options are enabled? 3. What options are enabled to create ext4? 4. Are image files (first.img, middle.img and last.img) same as your previous mail? http://marc.info/?l=linux-ext4&m=124992522305319&w=2 5. What arguments are set to EXT4_IOC_MOVE_EXT in your test case? Regards, Akira Fujita > Sep 4 23:21:05 bergwolf -- MARK -- > [ 3183.602852] Modules linked in: ext4 ppdev lp parport binfmt_misc i915 kvm_intel kvm uinput ipv6 cpufreq_userspace cpufreq_conservative cpufreq_powersave jbd2 crc16 fuse dm_snapshot dm_mirror dm_region_hash dm_log dm_mod zlib_deflate crc32c acpi_cpufreq sbp2 snd_hda_codec_analog snd_hda_intel snd_hda_codec snd_pcm_oss snd_mixer_oss pcmcia rtc_cmos snd_pcm rtc_core i2c_i801 rtc_lib snd_timer snd_page_alloc psmouse yenta_socket rsrc_nonstatic thinkpad_acpi pcmcia_core serio_raw evdev uhci_hcd firewire_ohci firewire_core crc_itu_t video output ehci_hcd e1000e usbcore [last unloaded: ext4] > [ 3183.602951] > [ 3183.602958] Pid: 6937, comm: a.out Not tainted (2.6.31-rc2-drm-intel-next #2) 7676A26 > [ 3183.602965] EIP: 0060:[<c01cfa26>] EFLAGS: 00210287 CPU: 1 > [ 3183.602977] EIP is at journal_start+0x39/0xb9 > [ 3183.602982] EAX: f61a2a80 EBX: f26f048c ECX: f6995200 EDX: f6995000 > [ 3183.602988] ESI: f26f048c EDI: f6f59c88 EBP: f1a77c90 ESP: f1a77c7c > [ 3183.602994] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 > [ 3183.603010] 00000002 f6995000 f6f59c88 f26f048c f6f59c88 f1a77c98 c01c9cc6 f1a77cac > [ 3183.603024] <0> c01c0b51 f6f59c88 00000001 f6995200 f1a77cc0 c0192799 004cba00 f6f59c88 > [ 3183.603039] <0> f68b3840 f1a77cd4 c018ab14 004cba00 00000000 ff7fc000 f1a77d44 c015c7ec > [ 3183.603070] [<c01c9cc6>] ? ext3_journal_start_sb+0x40/0x42 > [ 3183.603076] [<c01c0b51>] ? ext3_dirty_inode+0x24/0x67 > [ 3183.603087] [<c0192799>] ? __mark_inode_dirty+0x23/0xc6 > [ 3183.603097] [<c018ab14>] ? file_update_time+0x7a/0xa3 > [ 3183.603108] [<c015c7ec>] ? __generic_file_aio_write_nolock+0x2d6/0x3fe > [ 3183.603151] [<fa29d3b4>] ? ext4_ext_find_extent+0x3f/0x230 [ext4] > [ 3183.603161] [<c015d0e3>] ? generic_file_aio_write+0x57/0xb4 > [ 3183.603200] [<fa2a6c26>] ? mext_replace_branches+0x31f/0x329 [ext4] > [ 3183.603209] [<c01bef56>] ? ext3_file_write+0x1a/0x88 > [ 3183.603219] [<c017b6e2>] ? do_sync_write+0xab/0xe9 > [ 3183.603229] [<c0137403>] ? autoremove_wake_function+0x0/0x33 > [ 3183.603239] [<c013dbda>] ? getnstimeofday+0x52/0xda > [ 3183.603249] [<c014d027>] ? do_acct_process+0x68d/0x6b2 > [ 3183.603257] [<c015b46c>] ? find_get_page+0x1d/0x81 > [ 3183.603268] [<c018df9f>] ? mntput_no_expire+0x19/0xb3 > [ 3183.603276] [<c017c9c7>] ? __fput+0x17c/0x184 > [ 3183.603286] [<c014d09f>] ? acct_process+0x53/0x66 > [ 3183.603294] [<c012a318>] ? do_exit+0x174/0x573 > [ 3183.603303] [<c012a778>] ? do_group_exit+0x61/0x88 > [ 3183.603311] [<c012a7b2>] ? sys_exit_group+0x13/0x17 > [ 3183.603320] [<c0102994>] ? sysenter_do_call+0x12/0x28 > [ 3183.603419] ---[ end trace cba419e95b73d96f ]--- > > I'm not sure why ext3 journal is involved. I've run the case twice and both > turned out with the same trace messages. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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