On 6/11/15 3:07 PM, Eric Sandeen wrote:
> On 6/11/15 11:32 AM, Török Edwin wrote:
>
>> All commands below were run on armv7, and unmounted, the files from
>> /tmp copied over to x86-64, gzipped and uploaded, they were never
>> mounted on x86-64:
>>
>> # dd if=/dev/zero of=/tmp/xfs2.test bs=1M count=40
>> 40+0 records in
>> 40+0 records out
>> 41943040 bytes (42 MB) copied, 0.419997 s, 99.9 MB/s
>> # mkfs.xfs /tmp/xfs2.test
>> meta-data=/tmp/xfs2.test isize=256 agcount=2, agsize=5120 blks
>> = sectsz=512 attr=2, projid32bit=0
>> data = bsize=4096 blocks=10240, imaxpct=25
>> = sunit=0 swidth=0 blks
>> naming =version 2 bsize=4096 ascii-ci=0
>> log =internal log bsize=4096 blocks=1200, version=2
>> = sectsz=512 sunit=0 blks, lazy-count=1
>> realtime =none extsz=4096 blocks=0, rtextents=0
>> # cp /tmp/xfs2.test /tmp/xfs2.test.orig
>> # umount /export/dfs
>> # mount -o loop -t xfs /tmp/xfs2.test /export/dfs
>> # mkdir /export/dfs/a
>> # sxadm node --new --batch /export/dfs/a/b
>> # ls /export/dfs/a/b
>> ls: reading directory /export/dfs/a/b: Structure needs cleaning
>
> ok, so dir a/b/ is inode 150400
>
> # ls -id mnt/a/b
> 150400 mnt/a/b
>
> xfs_db> inode 150400
> xfs_db> p
> ...
> core.format = 2 (extents)
> ...
> u.bmx[0-2] = [startoff,startblock,blockcount,extentflag] 0:[0,9420,1,0] 1:[1,9553,1,0] 2:[8388608,9489,1,0]
>
> so those are the blocks it should be reading as directory data; somehow it's finding a superblock instead (?!)
>
> None of those physical blocks are particularly interesting; 9420, 9553, 9489 - nothing that could/should be weirdly shifted or overflowed or bit-flipped to read block 0, AFAICT.
>
> The hexdump below has superblock magic, and this filesystem has only 2 superblocks, at fs block 0 and fs block 8192. Nothing really in common with the 3 directory blocks above.
>
>> # umount /export/dfs
>> # cp /tmp/xfs2.test /tmp/xfs2.test.corrupted
>> # dmesg >/tmp/dmesg
>> # exit
>>
>> the latest corruption message from dmesg:
>> [4744604.870000] XFS (loop0): Mounting Filesystem
>> [4744604.900000] XFS (loop0): Ending clean mount
>> [4745016.610000] dc61e000: 58 46 53 42 00 00 10 00 00 00 00 00 00 00 28 00 XFSB..........(.
>> [4745016.620000] dc61e010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>> [4745016.630000] dc61e020: 64 23 d2 06 32 2e 4c 20 82 6e f0 36 a7 d9 54 f9 d#..2.L .n.6..T.
>> [4745016.640000] dc61e030: 00 00 00 00 00 00 20 04 00 00 00 00 00 00 00 80 ...... .........
>> [4745016.640000] XFS (loop0): Internal error xfs_dir3_data_read_verify at line 274 of file fs/xfs/xfs_dir2_data.c. Caller 0xc01c1528
>> [4745016.650000] CPU: 0 PID: 37 Comm: kworker/0:1H Not tainted 3.14.3-00088-g7651c68 #24
>> [4745016.650000] Workqueue: xfslogd xfs_buf_iodone_work
>> [4745016.650000] [<c0013948>] (unwind_backtrace) from [<c0011058>] (show_stack+0x10/0x14)
>> [4745016.650000] [<c0011058>] (show_stack) from [<c01c3dc4>] (xfs_corruption_error+0x54/0x70)
>> [4745016.650000] [<c01c3dc4>] (xfs_corruption_error) from [<c01f7854>] (xfs_dir3_data_read_verify+0x60/0xd0)
>> [4745016.650000] [<c01f7854>] (xfs_dir3_data_read_verify) from [<c01c1528>] (xfs_buf_iodone_work+0x7c/0x94)
>> [4745016.650000] [<c01c1528>] (xfs_buf_iodone_work) from [<c00309f0>] (process_one_work+0xf4/0x32c)
>> [4745016.650000] [<c00309f0>] (process_one_work) from [<c0030fb4>] (worker_thread+0x10c/0x388)
>> [4745016.650000] [<c0030fb4>] (worker_thread) from [<c0035e10>] (kthread+0xbc/0xd8)
>> [4745016.650000] [<c0035e10>] (kthread) from [<c000e8f8>] (ret_from_fork+0x14/0x3c)
>> [4745016.650000] XFS (loop0): Corruption detected. Unmount and run xfs_repair
>> [4745016.650000] XFS (loop0): metadata I/O error: block 0xa000 ("xfs_trans_read_buf_map") error 117 numblks 8
>
> ok, block 0xA000 (in sectors) is sector 40960...
>
> xfs_db> daddr 40960
> xfs_db> fsblock
> current fsblock is 8192
> xfs_db> type text
> xfs_db> p
> 000: 58 46 53 42 00 00 10 00 00 00 00 00 00 00 28 00 XFSB............
> 010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 020: 64 23 d2 06 32 2e 4c 20 82 6e f0 36 a7 d9 54 f9 d...2.L..n.6..T.
>
> ...
>
> Right, so it's reading the 2nd superblock in xfs_dir3_data_read_verify. Huh?
> (I could have imagined some weird scenario where we read block 0, but 8192?
> Very strange).
>
> Hm, I don't think this can be readahead, it'd not get to this verifier AFAICT.
>
> Given that the image is enough to reproduce via just mount; ls - we should be
> able to reproduce this, given the right hardware, and get to the bottom of it.
One other thing that might help:
# trace-cmd record -e xfs\* &
# <mount the image and do the ls test>
# kill %1
# trace-cmd report > trace_report.txt
and provide that info along w/ the dmesg when it fails.
(I assume it's the same, but just to be sure)
-Eric
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