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@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
