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Subject[f2fs-dev] [PATCH] f2fs: validate before set/clear free nat bitmap
Date
In flush_nat_entries, all dirty nats will be flushed and if
their new address isn't NULL_ADDR, their bitmaps will be updated,
the free_nid_count of the bitmaps will be increaced regardless
of whether the nats have already been occupied before.
This could lead to wrong free_nid_count.
So this patch checks the status of the bits beforeactually
set/clear them.

Signed-off-by: Fan li <fanofcode.li@samsung.com>
---
fs/f2fs/node.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index d234c6e..b965a53 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1906,15 +1906,18 @@ static void update_free_nid_bitmap(struct
f2fs_sb_info *sbi, nid_t nid,
if (!test_bit_le(nat_ofs, nm_i->nat_block_bitmap))
return;

- if (set)
+ if (set) {
+ if (test_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]))
+ return;
__set_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
- else
- __clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
-
- if (set)
nm_i->free_nid_count[nat_ofs]++;
- else if (!build)
- nm_i->free_nid_count[nat_ofs]--;
+ } else {
+ if (!test_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]))
+ return;
+ __clear_bit_le(nid_ofs, nm_i->free_nid_bitmap[nat_ofs]);
+ if (!build)
+ nm_i->free_nid_count[nat_ofs]--;
+ }
}

static void scan_nat_page(struct f2fs_sb_info *sbi,
--
2.7.4

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