On 2016/2/23 13:28, Chao Yu wrote: > Hi all, > >> -----Original Message----- >> From: Junling Zheng [mailto:zhengjunl...@huawei.com] >> Sent: Tuesday, February 23, 2016 11:47 AM >> To: linux-f2fs-devel@lists.sourceforge.net; jaeg...@kernel.org >> Subject: [f2fs-dev] [RFC PATCH v2] mkfs.f2fs: recalculate sit_segments by >> max_sit_bitmap_size >> >> In most cases, sit_bitmap_size is smaller than MAX_SIT_BITMAP_SIZE. >> >> However, in some extreme scenarios, such as 16TB, sit_bitmap_size >> could be larger than MAX_SIT_BITMAP_SIZE. >> >> In this case, we should recalculate the sit_segments through >> max_sit_bitmap_size to prevent sit_ver_bitmap_bytesize got from >> segment_count_sit in f2fs_write_check_point_pack() being over >> MAX_SIT_BITMAP_SIZE. >> >> Signed-off-by: Junling Zheng <zhengjunl...@huawei.com> >> --- >> mkfs/f2fs_format.c | 23 ++++++++++++++++------- >> 1 file changed, 16 insertions(+), 7 deletions(-) >> >> diff --git a/mkfs/f2fs_format.c b/mkfs/f2fs_format.c >> index 645c2aa..3a050e0 100644 >> --- a/mkfs/f2fs_format.c >> +++ b/mkfs/f2fs_format.c >> @@ -191,6 +191,22 @@ static int f2fs_prepare_super_block(void) >> >> sit_segments = SEG_ALIGN(blocks_for_sit); >> >> + /* >> + * In most cases, sit_bitmap_size is smaller than MAX_SIT_BITMAP_SIZE. >> + * However, in an extreme scenario(16TB), sit_bitmap_size could be >> larger >> + * than MAX_SIT_BITMAP_SIZE. Thus, we should recalculate the >> sit_segments >> + * to prevent sit_ver_bitmap_bytesize got from segment_count_sit in >> + * f2fs_write_check_point_pack() being over MAX_SIT_BITMAP_SIZE. >> + */ >> + sit_bitmap_size = (sit_segments << log_blks_per_seg) / 8; >> + >> + if (sit_bitmap_size > MAX_SIT_BITMAP_SIZE) { >> + max_sit_bitmap_size = MAX_SIT_BITMAP_SIZE; >> + sit_segments = max_sit_bitmap_size * 8 >> log_blks_per_seg; >> + blocks_for_sit = sit_segments << log_blks_per_seg; >> + } else > > Still the minor coding style problem. >
Do you mean the "else" also needs {} even though it has only one sentence? > IMO, maybe it would be better to limit config.total_sectors with 16TB at > very beginning, so more fields in sb like block_count, segment_count could > be set correctly when we try to format a huge size image. Right? > Limiting the disk at very beginning means not starting from 0 sector? Does it amount to reducing the size of disk to keep sit_bitmap_size smaller than MAX_SIT_BITMAP_SIZE? It looks to be helpful:) Indeed, the data in sb have no problem. Just the difference of calculating methods between sit_bitmap_size and MAX_SIT_BITMAP_SIZE: F2FS_MAX_SEGMENT: 16 * 1024 * 1024 / 2 = 8388608 max blocks_for_sit: ALIGN(F2FS_MAX_SEGMENT, SIT_ENTRY_PER_BLOCK) = 152521 // Upward here, not all blocks are used, some are redundant. max sit_segments: ALIGN(blocks_for_sit, config.blks_per_seg) = 298 // Upward here, not all segments are used, some are redundant. max segment_count_sit: sit_segments * 2 = 596 max sit_ver_bitmap_bytesize: ((segment_count_sit / 2) << log_blocks_per_seg) / 8 = 19072 // Here, bitmap size is too large because of the redundant blocks and segments. However, MAX_SIT_BITMAP_SIZE is defined as: ((F2FS_MAX_SEGMENT / SIT_ENTRY_PER_BLOCK) / 8) = 19065 // Downward here, abandon the redundant segments. So, the best way is to unify the two calculating method:) Thanks, > Thanks, > >> + max_sit_bitmap_size = sit_bitmap_size; >> + >> set_sb(segment_count_sit, sit_segments * 2); >> >> set_sb(nat_blkaddr, get_sb(sit_blkaddr) + get_sb(segment_count_sit) * >> @@ -208,13 +224,6 @@ static int f2fs_prepare_super_block(void) >> * This number resizes NAT bitmap area in a CP page. >> * So the threshold is determined not to overflow one CP page >> */ >> - sit_bitmap_size = ((get_sb(segment_count_sit) / 2) << >> - log_blks_per_seg) / 8; >> - >> - if (sit_bitmap_size > MAX_SIT_BITMAP_SIZE) >> - max_sit_bitmap_size = MAX_SIT_BITMAP_SIZE; >> - else >> - max_sit_bitmap_size = sit_bitmap_size; >> >> /* >> * It should be reserved minimum 1 segment for nat. >> -- >> 1.9.1 >> >> >> ------------------------------------------------------------------------------ >> Site24x7 APM Insight: Get Deep Visibility into Application Performance >> APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month >> Monitor end-to-end web transactions and take corrective actions now >> Troubleshoot faster and improve end-user experience. Signup Now! >> http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 >> _______________________________________________ >> Linux-f2fs-devel mailing list >> Linux-f2fs-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > > > . > ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel