[U-Boot] [PATCH v3 09/13] ext4: After completely filled group, scan next group from the beginning

Lukasz Majewski
2016-08-29T14:06:29Z

Hi Stefan,

> The last free block of a block group may be in its middle. After it
> has been allocated, the next block group should be scanned from its
> beginning.
>
> The following command triggers the bad behaviour (on a blocksize 1024
> fs):
>
> ./sandbox/u-boot -c 'i=0; host bind 0 ./disk.raw ;
> while test $i -lt 260 ; do echo $i; setexpr i $i + 1;
> ext4write host 0:2 0 /X${i} 0x1450; done ;
> ext4write host 0:2 0 /X240 0x2000 ; '
>
> When 'X240' is extended from 5200 byte to 8192 byte, the new blocks
> should start from the first free block (8811), but it uses the blocks
> 8098-8103 and 16296-16297 -- 8103 + 1 + 8192 = 16296. This can be
> shown with debugfs, commands 'ffb' and 'stat X240'.
>
> Signed-off-by: Stefan Br?ns <stefan.bruens@rwth-aachen.de>
> ---
> fs/ext4/ext4_common.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> v3: Patch added to series
>
> diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
> index 1ebdbe6..362668b 100644
> --- a/fs/ext4/ext4_common.c
> +++ b/fs/ext4/ext4_common.c
> @@ -895,8 +895,8 @@ uint32_t ext4fs_get_new_blk_no(void)
>
> goto fail;
> } else {
> -restart:
> fs->curr_blkno++;
> +restart:
> /* get the blockbitmap index respective to blockno */
> bg_idx = fs->curr_blkno / blk_per_grp;
> if (fs->blksz == 1024) {
> @@ -914,8 +914,9 @@ restart:
>
> if (bgd[bg_idx].free_blocks == 0) {
> debug("block group %u is full. Skipping\n",
> bg_idx);
> - fs->curr_blkno = fs->curr_blkno +
> blk_per_grp;
> - fs->curr_blkno--;
> + fs->curr_blkno = (bg_idx + 1) * blk_per_grp;
> + if (fs->blksz == 1024)
> + fs->curr_blkno += 1;
> goto restart;
> }
>
> @@ -932,6 +933,7 @@ restart:
> bg_idx) != 0) {
> debug("going for restart for the block no
> %ld %u\n", fs->curr_blkno, bg_idx);
> + fs->curr_blkno++;
> goto restart;
> }
>

Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>

--
Best regards,

Lukasz Majewski

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