[PATCH v2] f2fs: fix null page reference in redirty_blocks

[Daeho Jeong]

From: Daeho Jeong <daehoje...@google.com>

Fixed null page reference when find_lock_page() fails in
redirty_blocks().

Signed-off-by: Daeho Jeong <daehoje...@google.com>
Reported-by: Colin Ian King <colin.k...@canonical.com>
Fixes: 5fdb322ff2c2 ("f2fs: add F2FS_IOC_DECOMPRESS_FILE and 
F2FS_IOC_COMPRESS_FILE")
---
v2: changed error value and break the loop when error occurs
---
 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 9e5275716be8..d27173c24391 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4060,8 +4060,10 @@ 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);
-- 
2.29.2.729.g45daf8777d-goog