After applying the commit associated with the Fixes tag, metadata file buffers can be evicted from memory even after being marked dirty. Consequently, operations such as rolling back sufile changes upon error - which modify the buffer and were previously assumed incapable of failure - can now fail. This behavior causes syzbot to trigger a WARN_ON check immediately following sufile function calls within the log writer. Resolve this issue by introducing a macro, nilfs_sufile_warn_on_error(), which uses WARN_ONCE to report unexpected errors only when the filesystem has not degraded to read-only mode, returning -EIO or -EROFS accordingly. Replace existing WARN_ON checks for unexpected errors following sufile operations with this new macro. Additionally, for nilfs_segctor_truncate_segments() - where an error must be propagated to halt log writing if a sufile operation fails - modify the function to return the error code appropriately. Reported-by: syzbot+5957361606d7b750b874@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5957361606d7b750b874 Fixes: 8c26c4e2694a ("nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption") Cc: stable+noautosel@kernel.org # Warning suppression primarily; will request backport individually if needed Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>