From: Tao Ma <tm@tao.ma>
To: Boxi Liu <boxi10liu@gmail.com>
Cc: "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
Robin Dong <sanbai@taobao.com>, Theodore Tso <tytso@mit.edu>,
"lewis.liulei" <lewis.liulei@huawei.com>
Subject: Re: there is a BUG in disk full case in inlinedata feature.
Date: Wed, 28 Aug 2013 09:04:50 +0800 [thread overview]
Message-ID: <521D4CB2.2060805@tao.ma> (raw)
In-Reply-To: <CAAFszuVts-gn85SqPje=dibGFVo9GH6RKSJiOP6KtkZTgdDYNQ@mail.gmail.com>
Hi Boxi,
Thanks for the detailed explanation and the bug fix. It looks good to me.
So would you mind send out a formal patch?
Thanks,
Tao
On 08/28/2013 01:09 AM, Boxi Liu wrote:
> there is a BUG in EXT4 inlinedata feature when the disk is full(0B).
> tast case:
> step1: use the dd to make the disk full,has 0B remained.
> step2: touch a inlinedata file
> echo -n "123456" >> test.txt
> step3: make the inlinedata file test.txt convert to extent block.
> echo -n
> "123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890">>test.txt
> the step3 will write failed.and print the BUG Backtrace:
> page:c1963bc0 count:-1 mapcount:0 mapping: (null) index:0x0
> page flags:0x40000000()
> Backtrace:
> [<c004e180>] (dump_backtrace + 0x0/0x12c) from [<c07724ac>]
> (dump_stack +0x18/0x1c)
> r6:c0043a84 r5:c0bb688 r4:c1963bc0 r3:00000000
> [<c0772494>] (dump_stack + 0x0/0x1c) from [<c00f6dd4>] (bad_page + 0xbc/0x13c)
> [<c00fbd18>] (bad_page + 0x0/0x13c) from [<c00f74b80>]
> (get_page_from_freelist + 0x4cc/0xb6c)
> r7:c1963bd8 r6:c0043194 r5:c1963bc0 r4:00000001
> [<c00f6fec>] (get_page_from_freelist +0x0/0xb6c) from [<c00f8148>]
> (__alloc_pages_nodemask + 0x144/0x820)
> [<c00f8004>] (__alloc_pages_nodemask +0x0/0x820) from [<c0115250>]
> (handle_pte_fault + 0x574/0x758)
> [<c0114cdc>] (handle_pte_fault + 0x0/0x758) from [<c0115500>]
> (handle_mm_fault + 0xcc/0x110)
> [<c0115434>] (handel_mm_fault + 0x0/0x110) from [<c00521a8>]
> (do_page_fault + 0x16c/0x1f4)
> [<c005203c>] (do_page_fault + 0x0/0x1f4) from [<c00440d0>]
> (do_DataAbort + 0x40/0xac)
> [<c0044090>] (do_DataAbort + 0x0/0xac) from [<c004a064>]
> (ret_from_exception + 0x0/0x10)
>
> And when the system reboot , the step2 data "123456" will alse lost.
> You can cat the test.txt,but there is no data in the file.
> the reason is when the inlinedata convert to extent in the limit case,
> the inlinedata read to the page,then destory the inlinedata,next step
> is to __block_write_begin,but it can't get block,return -ENOSPC. so
> the data lost.
>
> there is a patch may fix the bug:
> in inline.c ext4_convert_inline_data_to_extent
>
> needed_blocks = ext4_writepage_trans_blocks(inode);
>
> + if(EXT4_C2B(sbi,percpu_counter_read_positive(&sbi->s_freeclusters_counter))
> < needed_blocks)
> + return -ENOSPC;
> +
> ret = ext4_get_inode_loc(inode, &iloc);
> if (ret)
> return ret;
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
next prev parent reply other threads:[~2013-08-28 1:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-27 17:09 there is a BUG in disk full case in inlinedata feature Boxi Liu
2013-08-28 1:04 ` Tao Ma [this message]
2013-08-29 15:15 ` Boxi Liu
2013-10-21 16:22 ` Boxi Liu
2013-10-21 17:48 ` Darrick J. Wong
2013-10-22 2:00 ` Tao Ma
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