From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:60748 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946320AbcHRMuR (ORCPT ); Thu, 18 Aug 2016 08:50:17 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: Vegard Nossum , Theodore Ts'o , "Aneesh Kumar K . V" , Jiri Slaby Subject: [patch added to 3.12-stable] ext4: fix reference counting bug on block allocation error Date: Thu, 18 Aug 2016 14:49:35 +0200 Message-Id: <20160818124953.31969-30-jslaby@suse.cz> In-Reply-To: <20160818124953.31969-1-jslaby@suse.cz> References: <20160818124953.31969-1-jslaby@suse.cz> Sender: stable-owner@vger.kernel.org List-ID: From: Vegard Nossum This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== 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 Signed-off-by: Jiri Slaby --- fs/ext4/mballoc.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 4a79ce1ecaa1..fcb205f69ed6 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2897,7 +2897,7 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, ext4_error(sb, "Allocating blocks %llu-%llu which overlap " "fs metadata", block, block+len); /* File system mounted not to panic on error - * Fix the bitmap and repeat the block allocation + * Fix the bitmap and return EUCLEAN * We leak some of the blocks here. */ ext4_lock_group(sb, ac->ac_b_ex.fe_group); @@ -2906,7 +2906,7 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, ext4_unlock_group(sb, ac->ac_b_ex.fe_group); err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh); if (!err) - err = -EAGAIN; + err = -EUCLEAN; goto out_err; } @@ -4476,18 +4476,7 @@ 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) { ext4_discard_allocated_blocks(ac); goto errout; } else { -- 2.9.3