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Date: Wed, 3 Feb 2016 06:08:52 +0000 From: "HUANG Weller (CM/ESW12-CN)" <Weller.Huang@...bosch.com> To: Xiong Zhou <jencce.kernel@...il.com> CC: "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>, "Li, Michael" <huayil@....qualcomm.com> Subject: RE: ext4 out of order when use cfq scheduler > -----Original Message----- > From: Xiong Zhou [mailto:jencce.kernel@...il.com] > Sent: Thursday, January 28, 2016 4:03 PM > To: HUANG Weller (CM/ESW12-CN) <Weller.Huang@...bosch.com> > Cc: linux-ext4@...r.kernel.org; Li, Michael <huayil@....qualcomm.com> > Subject: Re: ext4 out of order when use cfq scheduler > > On Tue, Dec 22, 2015 at 2:24 PM, HUANG Weller (CM/EPF1-CN) > <Weller.Huang@...bosch.com> wrote: > > Hi EXT4 developers, > > > > I am doing the power failure on a storage device. We are arm embedded system. > > Is there any chance that make this test a xfstest case ? > Do you mean use the xfstest tool to do the write test ? is there any difference or advantage to use xfstest ? > > > > > > Test environment: > > Kernel: 3.10.63 > > Test type: power failure > > File create type: O_SYNC flag enabled > > Mount option: data=ordered, journal_checksum,barrier=1 IO scheduler: > > CFQ > > > > Debug method: kernel print every block number of write request. print > > whether it is journal block. print whether it is (REQ_FUA | REQ_META | write) > After system startup, backup journal blocks before mount the test partition. > > > > Below is analysis which I think there is a out of order: > > hp0000017aMhWY3i0vMv is the file which checksum is error. Only half of the file > contents is correct. > > > > > > [root@...Fatlas6 ~]# debugfs /dev/nandblk0p3 debugfs 1.42.9 > > (28-Dec-2013) > > debugfs: imap test/hp0000017aMhWY3i0vMv Inode 390 is part of block > > group 0 > > located at block 141, offset 0x0280 > > > > 00000280 80 81 00 00 10 00 04 00 c8 09 00 00 66 0a 00 00 > > |............f...| > > 00000290 66 0a 00 00 00 00 00 00 00 00 01 00 04 02 00 00 > > |f...............| > > 000002a0 00 00 08 00 01 00 00 00 0a f3 02 00 04 00 00 00 > > |................| > > 000002b0 00 00 00 00 00 00 00 00 80 00 00 00 00 2c 01 00 > > |.............,..| ==> the file contents is at 0x00012c00 > > 000002c0 80 00 00 00 01 00 00 00 8e 26 01 00 00 00 00 00 > > |.........&......| > > > > > > Search the block number from the journal blocks: > > > > [root@...Fatlas6 ~]# hexdump j.bin -C | grep "00 2c 01 00" > > 00039ab0 00 00 00 00 00 00 00 00 80 00 00 00 00 2c 01 00 > > |.............,..| > > > > Search file name which the file checksum is error in journal blocks: > > > > [root@...Fatlas6 ~]# hexdump j.bin -C | grep "3i0vMv" -B1 > > 00030c60 86 01 00 00 1c 00 14 01 68 70 30 30 30 30 30 31 > > |........hp000001| > > 00030c70 37 61 4d 68 57 59 33 69 30 76 4d 76 88 01 00 00 > > |7aMhWY3i0vMv....| > > > > > > List all journal block record to check which journal block records it: > > > > [root@...Fatlas6 ~]# hexdump j.bin -C | grep "c0 3b 39 98" > > 00000000 c0 3b 39 98 00 00 00 04 00 00 00 00 00 00 08 00 > > |.;9.............| > > 00000800 c0 3b 39 98 00 00 00 05 00 00 00 6f 00 00 00 24 > > |.;9........o...$| > > 00001000 c0 3b 39 98 00 00 00 01 00 00 00 6f 00 00 00 75 > > |.;9........o...u| > > 0000c800 c0 3b 39 98 00 00 00 02 00 00 00 6f 00 00 00 00 > > |.;9........o....| > > 0000d000 c0 3b 39 98 00 00 00 01 00 00 00 70 00 00 00 65 > > |.;9........p...e| > > 00016000 c0 3b 39 98 00 00 00 02 00 00 00 70 00 00 00 00 > > |.;9........p....| > > 00016800 c0 3b 39 98 00 00 00 01 00 00 00 71 00 00 00 7c > > |.;9........q...|| > > 00021000 c0 3b 39 98 00 00 00 02 00 00 00 71 00 00 00 00 > > |.;9........q....| > > 00021800 c0 3b 39 98 00 00 00 01 00 00 00 72 00 00 00 82 > > |.;9........r....| > > 0002d000 c0 3b 39 98 00 00 00 02 00 00 00 72 00 00 00 00 > > |.;9........r....| > > 0002d800 c0 3b 39 98 00 00 00 01 00 00 00 73 00 00 00 88 |.;9........s....| > ==>00039ab0 is in last block, the file name and the start block number are all > recorded in the journals. > > 0003a000 c0 3b 39 98 00 00 00 02 00 00 00 73 00 00 00 00 > > |.;9........s....| > > > > > > Back to see the kernel log which it print all the block numbers: > > > > ... > > ... > > [ 46.222671] 244109 75277 > > [ 46.222693] > > [ 46.272438] 244352 75520 > > [ 46.272460] > > [ 46.348417] 238443 69611 > > [ 46.348438] > > [ 46.349811] 244480 75648 > > [ 46.352287] > > [ 46.404904] 244609 75777 > > [ 46.404926] > > [ 46.454698] 244738 75906 > > [ 46.454719] > > [ 46.505439] 244992 76160 > > [ 46.505459] > > [ 46.557783] 245120 76288 > > [ 46.557804] > > [ 46.610075] 245249 76417 > > [ 46.610096] > > [ 46.660196] 245378 76546 > > [ 46.660219] > > [ 46.709906] 201691 32859 ==> journal start is 32768, so the offset is 91, > block size=2048, so, the offset address in the j.bin is 0x2d800 > > [ 46.709928] J [ 46.711233] > > [ 46.740635] drop to 9v > > [ 46.749540] 201716 32884 > > [ 46.749560] J S > > [ 46.751039] > > [ 46.753151] 245632 76800 ==> 76800 in hex is 0x012c00, it is the same start > block of the file which checksum is error. > > [ 46.755284] > > nanddisk idle -> 1. > > [ 46.800227] 6v irq-2 > > > > > > The j.bin offset 0x2d800 > > > > 0002d800 c0 3b 39 98 00 00 00 01 00 00 00 73 00 00 00 88 > > |.;9........s....| ==>00039ab0 is in last block > > 0003a000 c0 3b 39 98 00 00 00 02 00 00 00 73 00 00 00 00 > > |.;9........s....| > > > > > > Normally, ext4 will first write the file contents, and then write the journal and > journal commit. Then after some delay, it will write the meta data. > > So The journal blocks contains the meta data of the file which the file contents > already been written before. > > But from above analysis, the journal sequence 0x73 already contain the file > name(hp0000017aMhWY3i0vMv) and the start block number(76800). So from the > kernel log, the block number(76800) should be available before the journal blocks > but NOT after it. > > It seems that there is out of order happen. > > > > Could you please help to check this issue ? or give a explanation about it ? > > Many thanks. > > > > Best regards > > > > Weller HUANG > > > > > > -- > > 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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