Hi Dave,

many thanks.

On 22/09/2015 23:27, Dave Chinner wrote:
> Urk, the command should be "fsync", not "sync". Regardless, the
> last bmap/fiemap pair shows something interesting:
>
> bmap-vp:
>
>> /media/p6/testfile:
>>   EXT: FILE-OFFSET      BLOCK-RANGE      AG AG-OFFSET        TOTAL FLAGS
>>     0: [0..127]:        96..223           0 (96..223)          128 00000
>>     1: [128..2047]:     hole                                  1920
>>     2: [2048..2559]:    2144..2655        0 (2144..2655)       512 10000
> fiemap -v:
>
>> /media/p6/testfile:
>>   EXT: FILE-OFFSET      BLOCK-RANGE      TOTAL FLAGS
>>     0: [0..127]:        96..223            128   0x0
>>     1: [128..2047]:     hole              1920
>>     2: [2048..2175]:    2144..2271         128 0x800
>>     3: [2176..2303]:    2272..2399         128   0x0
>>     4: [2304..2559]:    2400..2655         256 0x801
> Note that they are different - the former shows an unwritten extent
> of 256k @ offset 1MB, the later shows that extent split by 64k of
> data @ 1088k.
>
> The bmap -vp output is incorrect - it is supposed to sync data first
> and so should look the same as the fiemap output. Can you run this
> test again, this time with s/sync/fsync so the files are clean when
> bmap/fiemap are run? Can you run it a second time (umount/mkfs
> again) but with fiemap run first? i.e '-c "fiemap -v" -c "bmap -vp" \'
> instead of the original order?
>
> Next, can you compile your kernel with CONFIG_XFS_DEBUG=y and rerun
> the tests? Does anything interesting appear in dmesg during the test
> run?

Done, see mkfs_output_2.txt attached

> Not actually useful - I need to know what is happening inside the
> unlinkat() call.  I'm going to need a trace-cmd event dump of that
> xfs_io command and the subsequent rm (at least for the first couple
> of seconds of the rm). Please put the output file from the trace-cmd
> record command on a tmpfs filesystem so it doesn't pollute the xfs
> event trace ;)
>
I set some traces inside fs/namei.c  do_unlinkat()

root[243] vpc24 (master) /home/angelo/xfstests
# ./start_xfs_test.sh
QA output created by 308
[  144.822616] XFS (mmcblk0p5): Mounting V4 Filesystem
[  145.074537] XFS (mmcblk0p5): Starting recovery (logdev: internal)
[  145.107298] XFS (mmcblk0p5): Ending recovery (logdev: internal)
Silence is golden
[  145.413606] do_unlinkat(): entering
[  145.417124] do_unlinkat(): retry
[  145.421156] do_unlinkat(): retry_delegate
[  145.425920] do_unlinkat(): vfs_unlink returns 0
[  145.430950] do_unlinkat(): exit2

At least that function "seems" to complete, but, as from my previous 
message
looks like strace was not showing nothig over it.

I captured about 10 seconds of events after the "hang" on 308. Hope they 
are
enough.

File is quite long, so you can read it from here:
http://sysam.it/~angelo/events.txt

bye,

-- 
Best regards,
Angelo Dureghello