From: Daeho Jeong <redacted>

[ Upstream commit df0736d70c4fa6ed711ba103b61880fe72bb4777 ]

By Colin's static analysis, we found out there is a null page reference
under low memory situation in redirty_blocks. I've made the page finding
loop stop immediately and return an error not to cause further memory
pressure when we run into a failure to find a page under low memory
condition.

Signed-off-by: Daeho Jeong <redacted>
Reported-by: Colin Ian King <redacted>
Fixes: 5fdb322ff2c2 ("f2fs: add F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE")
Reviewed-by: Colin Ian King <redacted>
Reviewed-by: Chao Yu <redacted>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/f2fs/file.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index f585545277d77..cd62b0d3369ab 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c

@@ -4043,8 +4043,10 @@ static int redirty_blocks(struct inode *inode, pgoff_t page_idx, int len)
 
 	for (i = 0; i < page_len; i++, redirty_idx++) {
 		page = find_lock_page(mapping, redirty_idx);
-		if (!page)
-			ret = -ENOENT;
+		if (!page) {
+			ret = -ENOMEM;
+			break;
+		}
 		set_page_dirty(page);
 		f2fs_put_page(page, 1);
 		f2fs_put_page(page, 0);

-- 
2.27.0