f2fs: fix null page reference in redirty_blocks

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 <daehojeong@google.com>
Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: 5fdb322ff2 ("f2fs: add F2FS_IOC_DECOMPRESS_FILE and F2FS_IOC_COMPRESS_FILE")
Reviewed-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Daeho Jeong 2021-01-06 08:49:28 +09:00 committed by Jaegeuk Kim
parent 7f59b277f7
commit df0736d70c

View File

@ -4057,8 +4057,10 @@ 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);