Re: logfs unmount bug

* Re: logfs unmount bug
@ 2011-08-04 19:35 srimugunthan dhandapani
  2011-08-05 16:03   ` Jörn Engel
  0 siblings, 1 reply; 41+ messages in thread
From: srimugunthan dhandapani @ 2011-08-04 19:35 UTC (permalink / raw)
  To: Jörn Engel; +Cc: linux-fsdevel, linux-mtd

On Fri, Jul 22, 2011 at 12:35 AM, Jörn Engel <joern@logfs.org> wrote:
> On Tue, 19 July 2011 14:53:08 +0530, srimugunthan dhandapani wrote:
>>
>> Is the hardware the "Drais card" that you described in the following link
>> www.linux-kongress.org/2010/slides/logfs-engel.pdf
>
> Yes.
>
>> Since the driver exposes an mtd device, do you mount the ext4,btrfs
>> filesystem over any FTL?
>
> That was last year.  In the mean time I've added an FTL to the driver,
> so the card behaves like a regular ssd.  Well, mostly.
>
>> Is it possible to have logfs over the PCIe-SSD card?
>
> YeaaaNo!  Not anymore.  Could be lack of error correction in the
> current driver or could be bitrot.  Logfs over loopback seems to work
> just fine, so if it is bitrot, it is limited to the mtd interface.
>
>> Pardon me for asking the following in this thread.
>> I have been trying to mount logfs and i face  seg fault during unmount
>> . I have tested it in 2.6.34 and 2.39.1. I have asked about the
>> problem here.
>> http://comments.gmane.org/gmane.linux.file-systems/55008
>>
>> Two other people have also faced umount problem in logfs
>>
>> 1. http://comments.gmane.org/gmane.linux.file-systems/46630
>> 2. http://eeek.borgchat.net/lists/linux-embedded/msg02970.html
>>
>> My apologies again for asking it here. Since the logfs@logfs.org
>> mailing list(and the wiki) doesnt work any more , i am asking the
>> question here. I am thankful for your reply.
>
> Yes, ever since that machine died I have basically been the
> non-maintainer of logfs.  In a different century I would have been
> hanged, drawn and quartered for it.  Give me some time to test the mtd
> side and see what's up.
>
> Jörn

hi ,
With the latest kernel logfs unmount produces kernel BUG at
fs/logfs/segment.c:858[2]. The problem is in the invalidatepage
implementation of the device_mapping inode.
It is assumed  in the code that invalidatepage of the mapping_inode
shouldnt be invoked. The present invalidatepage implementation just
calls BUG(). I don't know why it is assumed like that.
But i modified the invalidatepage to clear the page private and update
flag as shown in patch [1]. With that, i tested with nandsim and  i am
able to do a clean unmount. I am curious to know what is correct
solution.

[1]
Signed-off-by: srimugunthan <srimugunthan.dhandapani@gmail.com>
---
 fs/logfs/segment.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c
index 9d51873..d83b778 100644
--- a/fs/logfs/segment.c
+++ b/fs/logfs/segment.c
@@ -855,7 +855,10 @@ static struct logfs_area *alloc_area(struct
super_block *sb)

 static void map_invalidatepage(struct page *page, unsigned long l)
 {
-	BUG();
+	ClearPagePrivate(page);
+	page->private = 0;
+	
+	ClearPageUptodate(page);
 }

 static int map_releasepage(struct page *page, gfp_t g)
-- 
1.7.0.4


---[2]
Aug  5 00:14:12 mll kernel: [  203.611029] LogFS: Start unmounting
Aug  5 00:14:12 mll kernel: [  203.612079] nand_erase_nand: start =
0x000000080000, len = 262144
Aug  5 00:14:12 mll kernel: [  203.612082] nand_isbad_bbt(): bbt info
for offs 0x00080000: (block 2) 0x00
Aug  5 00:14:12 mll kernel: [  203.612833] nand_sync: called
Aug  5 00:14:12 mll kernel: [  203.612864] nand_sync: called
Aug  5 00:14:12 mll kernel: [  203.613000] LogFS: Now in shutdown
Aug  5 00:14:12 mll kernel: [  203.613668] ------------[ cut here ]------------
Aug  5 00:14:12 mll kernel: [  203.613683] kernel BUG at fs/logfs/segment.c:858!
Aug  5 00:14:12 mll kernel: [  203.613689] invalid opcode: 0000 [#1] SMP
Aug  5 00:14:12 mll kernel: [  203.613696] CPU 2
Aug  5 00:14:12 mll kernel: [  203.613699] Modules linked in: mtdchar
nandsim nand nand_ids nand_ecc mtdblock mtd_blkdevs logfs zlib_deflate
binfmt_misc ppdev nfsd exportfs kvm_intel kvm nfs lockd auth_rpcgss
nfs_acl sunrpc adt7475 hwmon_vid nouveau fbcon tileblit font bitblit
snd_hda_codec_realtek softcursor snd_hda_intel ttm bridge
snd_hda_codec snd_hwdep drm_kms_helper snd_pcm_oss drm snd_mixer_oss
snd_pcm stp snd_seq_dummy lp snd_seq_oss snd_seq_midi parport
snd_rawmidi snd_seq_midi_event intel_agp hp_wmi i2c_algo_bit
sparse_keymap intel_gtt snd_seq mxm_wmi snd_timer snd_seq_device snd
psmouse serio_raw video soundcore snd_page_alloc usbhid hid ahci
e1000e libahci
Aug  5 00:14:12 mll kernel: [  203.613828]
Aug  5 00:14:12 mll kernel: [  203.613832] Pid: 2058, comm: umount
Tainted: G        W   3.0.0+ #2 Hewlett-Packard HP Z200
Workstation/0B40h
Aug  5 00:14:12 mll kernel: [  203.613843] RIP:
0010:[<ffffffffa034dd09>]  [<ffffffffa034dd09>]
map_invalidatepage+0x9/0x10 [logfs]
Aug  5 00:14:12 mll kernel: [  203.613856] RSP: 0018:ffff8800c79e9c28
EFLAGS: 00010286
Aug  5 00:14:12 mll kernel: [  203.613860] RAX: ffffffffa034dd00 RBX:
ffffea00030d03c0 RCX: 0000000000000009
Aug  5 00:14:12 mll kernel: [  203.613866] RDX: ffffffff81197860 RSI:
0000000000000000 RDI: ffffea00030d03c0
Aug  5 00:14:12 mll kernel: [  203.613872] RBP: ffff8800c79e9c28 R08:
ffff8800c79e9cf8 R09: b400000000000000
Aug  5 00:14:12 mll kernel: [  203.613877] R10: 0000000000000001 R11:
0000000000000000 R12: ffff8800c4fb0200
Aug  5 00:14:12 mll kernel: [  203.613882] R13: ffff8800c4fb0200 R14:
ffff8800c79e9c98 R15: 0000000000000000
Aug  5 00:14:12 mll kernel: [  203.613888] FS:  00007f8a551e8740(0000)
GS:ffff880112c00000(0000) knlGS:0000000000000000
Aug  5 00:14:12 mll kernel: [  203.613894] CS:  0010 DS: 0000 ES: 0000
CR0: 000000008005003b
Aug  5 00:14:12 mll kernel: [  203.613900] CR2: 00007f8a54886355 CR3:
00000000c7963000 CR4: 00000000000006e0
Aug  5 00:14:12 mll kernel: [  203.613906] DR0: 0000000000000000 DR1:
0000000000000000 DR2: 0000000000000000
Aug  5 00:14:12 mll kernel: [  203.613911] DR3: 0000000000000000 DR6:
00000000ffff0ff0 DR7: 0000000000000400
Aug  5 00:14:12 mll kernel: [  203.613917] Process umount (pid: 2058,
threadinfo ffff8800c79e8000, task ffff8800d7bd8000)
Aug  5 00:14:12 mll kernel: [  203.613923] Stack:
Aug  5 00:14:12 mll kernel: [  203.613925]  ffff8800c79e9c38
ffffffff81119378 ffff8800c79e9c58 ffffffff81119692
Aug  5 00:14:12 mll kernel: [  203.613936]  0000000000000080
ffffffffffffffff ffff8800c79e9d48 ffffffff81119a47
Aug  5 00:14:12 mll kernel: [  203.613947]  ffffea00030d03c0
0000000000000009 ffff8800c79e9cf8 0000000000000002
Aug  5 00:14:12 mll kernel: [  203.613957] Call Trace:
Aug  5 00:14:12 mll kernel: [  203.613964]  [<ffffffff81119378>]
do_invalidatepage+0x28/0x30
Aug  5 00:14:12 mll kernel: [  203.613969]  [<ffffffff81119692>]
truncate_inode_page+0x92/0xb0
Aug  5 00:14:12 mll kernel: [  203.613975]  [<ffffffff81119a47>]
truncate_inode_pages_range+0x177/0x4f0
Aug  5 00:14:12 mll kernel: [  203.613982]  [<ffffffff81119dd5>]
truncate_inode_pages+0x15/0x20
Aug  5 00:14:12 mll kernel: [  203.613989]  [<ffffffffa034d407>]
logfs_evict_inode+0x57/0x1d0 [logfs]
Aug  5 00:14:12 mll kernel: [  203.613996]  [<ffffffff812e325e>] ?
do_raw_spin_unlock+0x5e/0xb0
Aug  5 00:14:12 mll kernel: [  203.614004]  [<ffffffff81180d49>]
evict+0xa9/0x1a0
Aug  5 00:14:12 mll kernel: [  203.614009]  [<ffffffff81180f3d>] iput+0xfd/0x200
Aug  5 00:14:12 mll kernel: [  203.614015]  [<ffffffffa0347f00>]
logfs_put_super+0x30/0x40 [logfs]
Aug  5 00:14:12 mll kernel: [  203.614022]  [<ffffffff81168882>]
generic_shutdown_super+0x62/0xe0
Aug  5 00:14:12 mll kernel: [  203.614029]  [<ffffffffa034f8cf>]
logfs_kill_sb+0x4f/0xe0 [logfs]
Aug  5 00:14:12 mll kernel: [  203.614035]  [<ffffffff81169415>]
deactivate_locked_super+0x45/0x70
Aug  5 00:14:12 mll kernel: [  203.614041]  [<ffffffff8116a1aa>]
deactivate_super+0x4a/0x70
Aug  5 00:14:12 mll kernel: [  203.614047]  [<ffffffff8118544d>]
mntput_no_expire+0xed/0x140
Aug  5 00:14:12 mll kernel: [  203.614054]  [<ffffffff81185978>]
sys_umount+0x78/0x3b0
Aug  5 00:14:12 mll kernel: [  203.614063]  [<ffffffff815c44c2>]
system_call_fastpath+0x16/0x1b
Aug  5 00:14:12 mll kernel: [  203.614068] Code: 8b 41 10 48 8b 91 38
02 00 00 8b 89 40 02 00 00 48 d3 e6 44 89 c1 ff 50 28 c9 c3 0f 1f 80
00 00 00 00 55 48 89 e5 66 66 66 66 90 <0f> 0b eb fe 0f 1f 00 55 48 89
e5 66 66 66 66 90 31 c0 c9 c3 0f
Aug  5 00:14:12 mll kernel: [  203.614161] RIP  [<ffffffffa034dd09>]
map_invalidatepage+0x9/0x10 [logfs]
Aug  5 00:14:12 mll kernel: [  203.614169]  RSP <ffff8800c79e9c28>
Aug  5 00:14:12 mll kernel: [  203.617500] ---[ end trace 0b263dd4c3729069 ]---
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