On Tue, May 17, 2016 at 10:47:27PM +0200, Adam Borowski wrote:
> On Tue, May 17, 2016 at 12:23:44PM -0400, Chris Mason wrote:
> > On Tue, May 17, 2016 at 05:14:51PM +0200, Adam Borowski wrote:
> > > On Mon, May 16, 2016 at 05:06:55PM -0400, Chris Mason wrote:
> > > > And now for the patch:
> > > [...]
> > >
> > > I then tried your test case, and alas:
> > >
> > > Here's another run on an untainted kernel built with frame pointers etc:
> > >
> > > ./dammitdave foo
> > > [ 236.500257] ------------[ cut here ]------------
> > > [ 236.500280] WARNING: CPU: 3 PID: 2940 at fs/btrfs/extent-tree.c:4233
> > > btrfs_free_reserved_data_space_noquota+0xdd/0x160
> > > [ 236.500285] Modules linked in:
> > > [ 236.500295] CPU: 3 PID: 2940 Comm: dammit Not tainted 4.6.0debug+ #1
> > > [ 236.500301] Hardware name: System manufacturer System Product
> > > Name/M4A77T, BIOS 2401 05/18/2011
> > > [ 236.500306] 0000000000000000 0000000042ec2fb0 ffff88022d5ffbd8
> > > ffffffff816b1920
> > > [ 236.500315] ffffffff81f86e3f 0000000042ec2fb0 0000000000000000
> > > 0000000000000000
> > > [ 236.500322] ffff88022d5ffc20 ffffffff81118c2c ffff88022dfd4000
> > > 0000108900000000
> > > [ 236.500330] Call Trace:
> > > [ 236.500342] [<ffffffff816b1920>] dump_stack+0x60/0xa0
> > > [ 236.500352] [<ffffffff81118c2c>] __warn+0x10c/0x150
> > > [ 236.500360] [<ffffffff81118d78>] warn_slowpath_null+0x18/0x20
> > > [ 236.500368] [<ffffffff814e389d>]
> > > btrfs_free_reserved_data_space_noquota+0xdd/0x160
> > > [ 236.500376] [<ffffffff814e3942>]
> > > btrfs_free_reserved_data_space+0x22/0x40
> > > [ 236.500385] [<ffffffff8152eb78>] __btrfs_buffered_write+0x748/0xa20
> > > [ 236.500394] [<ffffffff81624bdc>] ?
> > > security_inode_need_killpriv+0x3c/0x60
> > > [ 236.500401] [<ffffffff815345ef>] btrfs_file_write_iter+0x4ff/0xb90
> > > [ 236.500410] [<ffffffff81341847>] __vfs_write+0x117/0x1d0
> > > [ 236.500417] [<ffffffff8134317d>] vfs_write+0xdd/0x290
> > > [ 236.500425] [<ffffffff813748bd>] ? __fget_light+0x4d/0x120
> > > [ 236.500432] [<ffffffff813453ee>] SyS_pwrite64+0x9e/0xc0
> > > [ 236.500441] [<ffffffff81db989f>] entry_SYSCALL_64_fastpath+0x17/0x93
> > > [ 236.500446] ---[ end trace 7df747a6a0962ae6 ]---
> > > rm foo
> > > [ 323.851851] BTRFS info (device sda1): btrfs_destroy_inode: leftover
> > > csum_bytes
> >
> > Hmmm, some of your traces mentioned compression, do you have compression
> > enabled?
>
> Yeah, I mount with noatime,compress=lzo.
>
> > I'll try to reproduce here, but could you try the same test on v4.5?
>
> I've ran it for half an hour on vanilla 4.5.4 without any patches, no
> failures of any kind.
>
> > Also, if you can gdb your vmlinux (or btrfs.ko) and find this line:
> >
> > gdb> list *__btrfs_buffered_write+0x748
>
> 0xffffffff8152eb78 is in __btrfs_buffered_write (fs/btrfs/file.c:1564).
> 1559
> 1560 reserve_metadata:
> 1561 ret = btrfs_delalloc_reserve_metadata(inode,
> reserve_bytes);
> 1562 if (ret) {
> 1563 if (!only_release_metadata)
> 1564 btrfs_free_reserved_data_space(inode,
> pos,
> 1565
> write_bytes);
> 1566 else
> 1567 btrfs_end_write_no_snapshoting(root);
> 1568 break;
>
Aha, so you're getting an enospc with compression on and the accounting
doesn't line up. I should be able to trigger this.
-chris
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