Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753614AbbLLUQl (ORCPT ); Sat, 12 Dec 2015 15:16:41 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:37228 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753521AbbLLUQj (ORCPT ); Sat, 12 Dec 2015 15:16:39 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hobin Woo , Daeho Jeong , Theodore Tso Subject: [PATCH 4.2 51/61] ext4, jbd2: ensure entering into panic after recording an error in superblock Date: Sat, 12 Dec 2015 12:06:19 -0800 Message-Id: <20151212200459.655792384@linuxfoundation.org> X-Mailer: git-send-email 2.6.4 In-Reply-To: <20151212200457.170255093@linuxfoundation.org> References: <20151212200457.170255093@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3612 Lines: 110 4.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daeho Jeong commit 4327ba52afd03fc4b5afa0ee1d774c9c5b0e85c5 upstream. If a EXT4 filesystem utilizes JBD2 journaling and an error occurs, the journaling will be aborted first and the error number will be recorded into JBD2 superblock and, finally, the system will enter into the panic state in "errors=panic" option. But, in the rare case, this sequence is little twisted like the below figure and it will happen that the system enters into panic state, which means the system reset in mobile environment, before completion of recording an error in the journal superblock. In this case, e2fsck cannot recognize that the filesystem failure occurred in the previous run and the corruption wouldn't be fixed. Task A Task B ext4_handle_error() -> jbd2_journal_abort() -> __journal_abort_soft() -> __jbd2_journal_abort_hard() | -> journal->j_flags |= JBD2_ABORT; | | __ext4_abort() | -> jbd2_journal_abort() | | -> __journal_abort_soft() | | -> if (journal->j_flags & JBD2_ABORT) | | return; | -> panic() | -> jbd2_journal_update_sb_errno() Tested-by: Hobin Woo Signed-off-by: Daeho Jeong Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/super.c | 12 ++++++++++-- fs/jbd2/journal.c | 6 +++++- include/linux/jbd2.h | 1 + 3 files changed, 16 insertions(+), 3 deletions(-) --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -397,9 +397,13 @@ static void ext4_handle_error(struct sup smp_wmb(); sb->s_flags |= MS_RDONLY; } - if (test_opt(sb, ERRORS_PANIC)) + if (test_opt(sb, ERRORS_PANIC)) { + if (EXT4_SB(sb)->s_journal && + !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR)) + return; panic("EXT4-fs (device %s): panic forced after error\n", sb->s_id); + } } #define ext4_error_ratelimit(sb) \ @@ -588,8 +592,12 @@ void __ext4_abort(struct super_block *sb jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO); save_error_info(sb, function, line); } - if (test_opt(sb, ERRORS_PANIC)) + if (test_opt(sb, ERRORS_PANIC)) { + if (EXT4_SB(sb)->s_journal && + !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR)) + return; panic("EXT4-fs panic from previous error\n"); + } } void __ext4_msg(struct super_block *sb, --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -2071,8 +2071,12 @@ static void __journal_abort_soft (journa __jbd2_journal_abort_hard(journal); - if (errno) + if (errno) { jbd2_journal_update_sb_errno(journal); + write_lock(&journal->j_state_lock); + journal->j_flags |= JBD2_REC_ERR; + write_unlock(&journal->j_state_lock); + } } /** --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1007,6 +1007,7 @@ struct journal_s #define JBD2_ABORT_ON_SYNCDATA_ERR 0x040 /* Abort the journal on file * data write error in ordered * mode */ +#define JBD2_REC_ERR 0x080 /* The errno in the sb has been recorded */ /* * Function declarations for the journaling transaction and buffer -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/