f2fs: reject setattr size changes on large folio files

f2fs: reject setattr size changes on large folio files

F2FS large folios are only enabled for immutable non-compressed files.
Writable open and writable mmap reject such mappings, but truncate(2)
through f2fs_setattr() misses the same guard.

If FS_IMMUTABLE_FL is cleared while the inode is still cached, the mapping
can keep large-folio support and ATTR_SIZE can change i_size. Reject size
changes in that state.

Cc: stable@kernel.org
Fixes: 05e65c14ea59 ("f2fs: support large folio for immutable non-compressed case")
Signed-off-by: Wenjie Qi <qiwenjie@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>