[PATCH 5.15.y 1/2] f2fs: fix to adjust appropirate defragment pg_end

[Sasha Levin <sashal@kernel.org>]

From: Zhiguo Niu <zhiguo.niu@unisoc.com>

[ Upstream commit 197080156f27b6bf8cf198e9313dfbb94769c736 ]

A length that exceeds the real size of the inode may be
specified from user, although these out-of-range areas
are not mapped, but they still need to be check in
while loop, which is unnecessary.

Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Stable-dep-of: 92154fe28c37 ("f2fs: fix defragment writeback range truncation on 32-bit")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/file.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 892f19f67904f..36a2fbfc19997 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2616,12 +2616,13 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 	bool fragmented = false;
 	int err;
 
-	pg_start = range->start >> PAGE_SHIFT;
-	pg_end = (range->start + range->len) >> PAGE_SHIFT;
-
 	f2fs_balance_fs(sbi, true);
 
 	inode_lock(inode);
+	pg_start = range->start >> PAGE_SHIFT;
+	pg_end = min_t(pgoff_t,
+				(range->start + range->len) >> PAGE_SHIFT,
+				DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE));
 
 	/* if in-place-update policy is enabled, don't waste time here */
 	set_inode_flag(inode, FI_OPU_WRITE);
@@ -2631,8 +2632,9 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 	}
 
 	/* writeback all dirty pages in the range */
-	err = filemap_write_and_wait_range(inode->i_mapping, range->start,
-						range->start + range->len - 1);
+	err = filemap_write_and_wait_range(inode->i_mapping,
+						pg_start << PAGE_SHIFT,
+						(pg_end << PAGE_SHIFT) - 1);
 	if (err)
 		goto out;
 
-- 
2.53.0