Hi Jaegeuk, On Sun, Mar 08, 2015 at 09:18:47PM -0700, Jaegeuk Kim wrote: >Hi Wanpeng, > >On Mon, Mar 09, 2015 at 11:00:54AM +0800, Wanpeng Li wrote: >> The blocks of nat pages to be scanned will be readahead when build free >> nids. The start blkno will be adjusted to 0 when the intended range over >> max_nids, then function ra_meta_pages readahead the right blkno, however, >> function get_current_nat_page which is called in build_free_nids still >> get the meta pages w/ stale blkno, this patch fix it by adjusting the nid >> and the blkno which will be readahead in avdance in order to readahead and >> get the right meta pages. >> >> Signed-off-by: Wanpeng Li <wanpeng...@linux.intel.com> >> --- >> fs/f2fs/checkpoint.c | 3 --- >> fs/f2fs/node.c | 9 ++++++++- >> 2 files changed, 8 insertions(+), 4 deletions(-) >> >> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c >> index 53bc328..aedb441 100644 >> --- a/fs/f2fs/checkpoint.c >> +++ b/fs/f2fs/checkpoint.c >> @@ -129,9 +129,6 @@ int ra_meta_pages(struct f2fs_sb_info *sbi, block_t >> start, int nrpages, int type >> >> switch (type) { >> case META_NAT: >> - if (unlikely(blkno >= >> - NAT_BLOCK_OFFSET(NM_I(sbi)->max_nid))) >> - blkno = 0; >> /* get nat block addr */ >> fio.blk_addr = current_nat_addr(sbi, >> blkno * NAT_ENTRY_PER_BLOCK); >> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c >> index 1a7e925..8751375 100644 >> --- a/fs/f2fs/node.c >> +++ b/fs/f2fs/node.c >> @@ -1509,13 +1509,20 @@ static void build_free_nids(struct f2fs_sb_info *sbi) >> struct f2fs_summary_block *sum = curseg->sum_blk; >> int i = 0; >> nid_t nid = nm_i->next_scan_nid; >> + block_t blkno = NAT_BLOCK_OFFSET(nid); >> >> /* Enough entries */ >> if (nm_i->fcnt > NAT_ENTRY_PER_BLOCK) >> return; >> >> + if (unlikely(blkno >= >> + NAT_BLOCK_OFFSET(NM_I(sbi)->max_nid))) { >> + blkno = 0; >> + nid = 0; >> + } > >The assumption here is that the nid does not exceeed max_nid, since the >previous call already set next_scan_nid to 0, if it exceeds max_nid. >So, we don't need to do like this.
So get_current_nat_page in while(1) still get the wrong meta page for one time, right? The nid will be set to 0 in the second round. Regards, Wanpeng Li > >BTW, even if ra_meta_pages doesn't get the below condition, > if (unlikely(blkno >= > NAT_BLOCK_OFFSET(NM_I(sbi)->max_nid))) > blkno = 0; >IMO, it is still worth to remain that to avoid any bugs due to further code >changes. It makes sense that unlikely was used for this too. > >Thanks, > >> + >> /* readahead nat pages to be scanned */ >> - ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), FREE_NID_PAGES, META_NAT); >> + ra_meta_pages(sbi, blkno, FREE_NID_PAGES, META_NAT); >> >> while (1) { >> struct page *page = get_current_nat_page(sbi, nid); >> -- >> 1.9.1 ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel