Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933844AbcKNCY0 (ORCPT ); Sun, 13 Nov 2016 21:24:26 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:47094 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933796AbcKNCYT (ORCPT ); Sun, 13 Nov 2016 21:24:19 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Aneesh Kumar K.V" , "Vegard Nossum" , "Theodore Ts'o" Date: Mon, 14 Nov 2016 00:14:07 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 025/152] ext4: fix reference counting bug on block allocation error In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2541 Lines: 75 3.2.84-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Vegard Nossum commit 554a5ccc4e4a20c5f3ec859de0842db4b4b9c77e upstream. If we hit this error when mounted with errors=continue or errors=remount-ro: EXT4-fs error (device loop0): ext4_mb_mark_diskspace_used:2940: comm ext4.exe: Allocating blocks 5090-6081 which overlap fs metadata then ext4_mb_new_blocks() will call ext4_mb_release_context() and try to continue. However, ext4_mb_release_context() is the wrong thing to call here since we are still actually using the allocation context. Instead, just error out. We could retry the allocation, but there is a possibility of getting stuck in an infinite loop instead, so this seems safer. [ Fixed up so we don't return EAGAIN to userspace. --tytso ] Fixes: 8556e8f3b6 ("ext4: Don't allow new groups to be added during block allocation") Signed-off-by: Vegard Nossum Signed-off-by: Theodore Ts'o Cc: Aneesh Kumar K.V [bwh: Backported to 3.2: - Use EIO instead of EFSCORRUPTED - Adjust context] Signed-off-by: Ben Hutchings --- fs/ext4/mballoc.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2824,7 +2824,7 @@ ext4_mb_mark_diskspace_used(struct ext4_ ext4_error(sb, "Allocating blocks %llu-%llu which overlap " "fs metadata\n", block, block+len); /* File system mounted not to panic on error - * Fix the bitmap and repeat the block allocation + * Fix the bitmap and return EIO * We leak some of the blocks here. */ ext4_lock_group(sb, ac->ac_b_ex.fe_group); @@ -2833,7 +2833,7 @@ ext4_mb_mark_diskspace_used(struct ext4_ ext4_unlock_group(sb, ac->ac_b_ex.fe_group); err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh); if (!err) - err = -EAGAIN; + err = -EIO; goto out_err; } @@ -4401,18 +4401,7 @@ repeat: } if (likely(ac->ac_status == AC_STATUS_FOUND)) { *errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs); - if (*errp == -EAGAIN) { - /* - * drop the reference that we took - * in ext4_mb_use_best_found - */ - ext4_mb_release_context(ac); - ac->ac_b_ex.fe_group = 0; - ac->ac_b_ex.fe_start = 0; - ac->ac_b_ex.fe_len = 0; - ac->ac_status = AC_STATUS_CONTINUE; - goto repeat; - } else if (*errp) + if (*errp) errout: ext4_discard_allocated_blocks(ac); else {