[PATCH 1/4] f2fs: limit b_size of mapped bh in f2fs_map_bh

[Chao Yu]

Map bh over max size which caller defined is not needed, limit it in
f2fs_map_bh.

Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
---
 fs/f2fs/data.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index f0a18a0..a99bc7f 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -255,15 +255,16 @@ static void f2fs_map_bh(struct super_block *sb, pgoff_t pgofs,
 			struct extent_info *ei, struct buffer_head *bh_result)
 {
 	unsigned int blkbits = sb->s_blocksize_bits;
+	unsigned int maxblocks = bh_result->b_size >> blkbits;
 	size_t count;
 
 	clear_buffer_new(bh_result);
 	map_bh(bh_result, sb, ei->blk + pgofs - ei->fofs);
 	count = ei->fofs + ei->len - pgofs;
-	if (count < (UINT_MAX >> blkbits))
-		bh_result->b_size = (count << blkbits);
+	if (count > maxblocks)
+		bh_result->b_size = maxblocks << blkbits;
 	else
-		bh_result->b_size = UINT_MAX;
+		bh_result->b_size = count << blkbits;
 }
 
 static bool lookup_extent_info(struct inode *inode, pgoff_t pgofs,
-- 
2.3.3


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