From 03b72b154413bd3539f66ec8c7bbbad85edeea5c Mon Sep 17 00:00:00 2001 From: Sahitya Tummala Date: Fri, 14 Aug 2020 10:42:44 +0530 Subject: [PATCH] f2fs: fix indefinite loop scanning for free nid If the sbi->ckpt->next_free_nid is not NAT block aligned and if there are free nids in that NAT block between the start of the block and next_free_nid, then those free nids will not be scanned in scan_nat_page(). This results into mismatch between nm_i->available_nids and the sum of nm_i->free_nid_count of all NAT blocks scanned. And nm_i->available_nids will always be greater than the sum of free nids in all the blocks. Under this condition, if we use all the currently scanned free nids, then it will loop forever in f2fs_alloc_nid() as nm_i->available_nids is still not zero but nm_i->free_nid_count of that partially scanned NAT block is zero. Fix this to align the nm_i->next_scan_nid to the first nid of the corresponding NAT block. Change-Id: Ib979f5529a531ee6f4960eaadebc4d7340317bf5 Signed-off-by: Sahitya Tummala --- fs/f2fs/node.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 450b58361de6..0c272d1e0975 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -2371,6 +2371,9 @@ static int __f2fs_build_free_nids(struct f2fs_sb_info *sbi, if (unlikely(nid >= nm_i->max_nid)) nid = 0; + if (unlikely(nid % NAT_ENTRY_PER_BLOCK)) + nid = NAT_BLOCK_OFFSET(nid) * NAT_ENTRY_PER_BLOCK; + /* Enough entries */ if (nm_i->nid_cnt[FREE_NID] >= NAT_ENTRY_PER_BLOCK) return 0;