On Tue, Feb 12, 2013 at 10:28:19PM -0500, Theodore Ts'o wrote:
> On Fri, Feb 08, 2013 at 04:44:00PM +0800, Zheng Liu wrote:
> > From: Zheng Liu <wenqing.lz@xxxxxxxxxx>
> >
> > By recording the phycisal block and status, extent status tree is able
> > to track the status of every extents. When we call _map_blocks
> > functions to lookup an extent or create a new written/unwritten/delayed
> > extent, this extent will be inserted into extent status tree. The hole
> > extent is inserted in ext4_ext_put_gap_in_cache(). If there is no any
> > extent, we will not insert a hole extent [0, ~0] into the extent status
> > tree in order to reduce the complextiy of code.
> >
> > We don't load all extents from disk in alloc_inode() because it costs
> > too much memory, and if a file is opened and closed frequently it will
> > takes too much time to load all extent information. So currently when
> > we create/lookup an extent, this extent will be inserted into extent
> > status tree. Hence, the extent status tree may not comprehensively
> > contain all of the extents found in the file.
> >
> > Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
> > Cc: "Theodore Ts'o" <tytso@xxxxxxx>
> > Cc: Jan kara <jack@xxxxxxx>
>
> Unfortunately, this commit is apparently causing test failures with
> bigalloc:
>
> --- 013.out 2013-01-01 22:52:04.000000000 -0500
> +++ 013.out.bad 2013-02-12 22:08:47.110766615 -0500
> @@ -8,7 +8,4 @@
> -----------------------------------------------
> fsstress.2 : -p 20 -r
> -----------------------------------------------
> -
> ------------------------------------------------
> -fsstress.3 : -p 4 -z -f rmdir=10 -f link=10 -f creat=10 -f mkdir=10 -f rename=30 -f stat=30 -f unlink=30 -f truncate=20
> ------------------------------------------------
> +_check_generic_filesystem: filesystem on /dev/vdd is inconsistent (see 013.full)
> _check_generic_filesystem: filesystem on /dev/vdd is inconsistent (see 013.full)
> Ran: 013
> Failures: 013
> Failed 1 of 1 tests
> END TEST: Ext4 4k block w/bigalloc Tue Feb 12 22:08:49 EST 2013
> e2fsck 1.43-WIP (15-Jan-2013)
> Pass 1: Checking inodes, blocks, and sizes
> Inode 618, i_blocks is 1408, should be 1536. Fix? yes
>
> Pass 2: Checking directory structure
> Pass 3: Checking directory connectivity
> Pass 4: Checking reference counts
> Pass 5: Checking group summary information
>
> /dev/vdd: ***** FILE SYSTEM WAS MODIFIED *****
> /dev/vdd: 3969/81936 files (13.1% non-contiguous), 176208/1310720 blocks
>
>
> I haven't been able to figure out what is going on here, but if we
> can't figure this out I may need to push off this patch series to the
> next merge window. I've tried splitting up this patch into two pieces
> to make it clearer what is going on, but I still can't see how this
> would be affecting the i_blocks calculation.
Hi Ted,
Oops, I run xfstests #13 serveral times and this bug can be triggered.
Sorry about that. I will look at it, but I am not sure whether it can
be fixed before merge window opens. Thanks for let me know.
For this bug, I guess that the problem is in ext4_da_invalidatepages()
because when a file is truncated this function will be called. But it
seems that the delay space reservation is the root cause. Ah, let me
trace it.
Regards,
- Zheng
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