nilfs2: replace nilfs_warning() with nilfs_msg()

Use nilfs_msg() to output warning messages and get rid of
nilfs_warning() function.  This also removes function names from the
messages unless we embed them explicitly in format strings.  Instead,
some messages are revised to clarify the context.

[arnd@arndb.de: avoid warning about unused variables]
  Link: http://lkml.kernel.org/r/20160615201945.3348205-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/1464875891-5443-6-git-send-email-konishi.ryusuke@lab.ntt.co.jp
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/nilfs2/ifile.c

@@ -151,8 +151,8 @@ int nilfs_ifile_get_inode_block(struct inode *ifile, ino_t ino,
 
 	err = nilfs_palloc_get_entry_block(ifile, ino, 0, out_bh);
 	if (unlikely(err))
-		nilfs_warning(sb, __func__, "unable to read inode: %lu",
-			      (unsigned long) ino);
+		nilfs_msg(sb, KERN_WARNING, "error %d reading inode: ino=%lu",
+			  err, (unsigned long)ino);
 	return err;
 }