Re: [PATCH] add check do_direct_IO() return val

[wengang wang <wen.gang.wang@oracle.com>]

Hi all,
Add some backgrounds:

When doing fio test on kernel 2.6.22,  we got oops,
--------------------------------------------------------------
BUG: unable to handle kernel paging request at virtual address 23c070bf
printing eip:
c04a07fd
*pdpt = 000000001ff88001
*pde = 0000000000000000
Oops: 0000 [#1]
SMP
Modules linked in: netconsole autofs4 hidp nfs lockd nfs_acl rfcomm l2cap
bluetooth sunrpc ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr
/@ iscsi_tcp libiscsi scsi_transport_iscsi dm_mirror dm_multipath dm_mod 
video /
sbs button battery ac ipv6 parport_pc lp parport i2c_piix4 i2c_core 
cfi_probe
gen_probe floppy scb2_flash sg mtdcore chipreg tg3 e1000 serio_raw ide_cd
/@ cdrom aic7xxx scsi_transport_spi sd_mod scsi_mod ext3 jbd ehci_hcd 
ohci_hcd /
uhci_hcd
CPU:    0
EIP:    0060:[<c04a07fd>]    Not tainted VLI
EFLAGS: 00010293   (2.6.22 #2)
EIP is at bio_get_nr_vecs+0x0/0x30
eax: 23c07063   ebx: 00000003   ecx: ffffffff   edx: 00000000
esi: de5cef74   edi: f54a9600   ebp: 00000000   esp: de5ceca8
ds: 007b   es: 007b   fs: 00d8  gs: 0033  ss: 0068
Process fio (pid: 17820, ti=de5ce000 task=de6570e0 task.ti=de5ce000)
Stack: c04a1c9d ffffffff ffffffff 00000009 f54a9600 de5cef74 00000000
f54a9600
      c04a1f43 00000000 c04a2b46 c0460466 c2c5baa0 c0812500 c0462c0a
00000001
      00000001 df4b90d4 de5ceee4 00000011 00000001 00000009 00000009
00000000
Call Trace:
[<c04a1c9d>] dio_new_bio+0x82/0xfe
[<c04a1f43>] dio_send_cur_page+0x4a/0x92
[<c04a2b46>] __blockdev_direct_IO+0xa09/0xc83
[<c0460466>] __pagevec_free+0x14/0x1a
[<c0462c0a>] release_pages+0x137/0x13f
[<f8856f30>] journal_start+0xaf/0xdd [jbd]
[<f8890fec>] ext3_direct_IO+0xfd/0x190 [ext3]
[<f888f6af>] ext3_get_block+0x0/0xd0 [ext3]
[<c045d803>] generic_file_direct_IO+0xe5/0x116
[<c045d890>] generic_file_direct_write+0x5c/0x137
[<c045e285>] __generic_file_aio_write_nolock+0x37b/0x4df
[<c045e43e>] generic_file_aio_write+0x55/0xb3
[<f888cfdc>] ext3_file_write+0x24/0x8f [ext3]
[<c0481af9>] do_sync_write+0xc7/0x10a
[<c04347d2>] check_kill_permission+0xec/0xf5
[<c043c557>] autoremove_wake_function+0x0/0x35
[<c0481a32>] do_sync_write+0x0/0x10a
[<c048233e>] vfs_write+0xa8/0x154
/@  [<c0482a1a>] sys_pwrite64+0x48/0x5f/
[<c0404e12>] syscall_call+0x7/0xb
[<c0620000>] xfrm_replay_timer_handler+0x3e/0x44
=======================
Code: 89 c5 c7 44 24 14 f4 ff ff ff 74 d2 e9 b3 fe ff ff 83 7c 24 34 00 
0f 84
0b ff ff ff e9 51 ff ff ff 83 c4 20 89 e8 5b 5e 5f 5d c3 <8b> 40 5c 8b 
48 38
8b 81 20 01 00 00 0f b7 91 2a 01 00 00 0f b7
EIP: [<c04a07fd>] bio_get_nr_vecs+0x0/0x30 SS:ESP 0068:de5ceca8

-----------------------------------------------------------

jobfile is
-------------------------------
/@ [global]/
/@ bs=8k/
/@ iodepth=1024/
/@ iodepth_batch=60/
/@ randrepeat=1/
/@ size=1m/
/@ directory=/home/oracle/
/@ numjobs=20/
/@ [job1]/
/@ ioengine=sync/
/@ bs=1k/
/@ direct=1/
/@ rw=randread/
/@ filename=file1:file2/
/@ [job2]/
/@ ioengine=libaio/
/@ rw=randwrite/
/@ direct=1/
/@ filename=file1:file2/
/@ [job3]/
/@ bs=1k/
/@ ioengine=posixaio/
/@ rw=randwrite/
/@ direct=1/
/@ filename=file1:file2/
/@ [job4]/
/@ ioengine=splice/
/@ direct=1/
/@ rw=randwrite/
/@ filename=file1:file2/
/@ [job5]/
/@ bs=1k/
/@ ioengine=sync/
/@ rw=randread/
/@ filename=file1:file2/
/@ [job7]/
/@ ioengine=libaio/
/@ rw=randwrite/
/@ filename=file1:file2/
/@ [job8]/
/@ ioengine=posixaio/
/@ rw=randwrite/
/@ filename=file1:file2/
/@ [job9]/
/@ ioengine=splice/
/@ rw=randwrite/
/@ filename=file1:file2/
/@ [job10]/
/@ ioengine=mmap/
/@ rw=randwrite/
/@ bs=1k/
/@ filename=file1:file2/
/@ [job11]/
/@ ioengine=mmap/
/@ rw=randwrite/
/@ direct=1/
/@ filename=file1:file2/
-------------------------------
ignore the @ please.


With Joe's patch, seems the oops solved.
So, please give a review to see if there is any problem for that patch.

thanks,
wengang.

**Joe Jin wrote:
> This is the patch for check do_direct_IO() return val.
>
> At do_direct_IO(), sometimes dio_get_page() will return -EFAULT/-ENOMEM,
> according to orig source, it will go on left work. buf for dio_get_page()
> return a error will made many useful member of dio not initialized like
> dio->map_bh and others, at this point, kernel will panic.
>
> Signed-off-by: Joe Jin <joe.jin@oracle.com>
>
>
> ---
> --- linux-2.6.22/fs/direct-io.c.orig	2007-07-26 11:32:27.000000000 +0800
> +++ linux-2.6.22/fs/direct-io.c	2007-07-26 11:33:58.000000000 +0800
> @@ -1031,7 +1031,9 @@ direct_io_worker(int rw, struct kiocb *i
>  			((dio->final_block_in_request - dio->block_in_file) <<
>  					blkbits);
>  
> -		if (ret) {
> +		if (ret == -EFAULT || ret == -ENOMEM) 
> +			goto out;
> +		else if (ret) {
>  			dio_cleanup(dio);
>  			break;
>  		}
> @@ -1113,6 +1115,7 @@ direct_io_worker(int rw, struct kiocb *i
>  	} else
>  		BUG_ON(ret != -EIOCBQUEUED);
>  
> +out:
>  	return ret;
>  }
>  
>   

--
Wengang Wang
Member of Technical Staff
Oracle Asia R&D Center
Open Source Technologies Development

Tel:      +86 10 8278 6265
Mobile:   +86 13381078925

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