Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752893AbaBGLY1 (ORCPT ); Fri, 7 Feb 2014 06:24:27 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:40807 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751574AbaBGLXd (ORCPT ); Fri, 7 Feb 2014 06:23:33 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jan Kara , "Theodore Ts'o" , Kamal Mostafa , Luis Henriques Subject: [PATCH 3.5 01/88] ext4: fix deadlock when writing in ENOSPC conditions Date: Fri, 7 Feb 2014 11:21:58 +0000 Message-Id: <1391772205-22239-2-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1391772205-22239-1-git-send-email-luis.henriques@canonical.com> References: <1391772205-22239-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.30 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit 34cf865d54813aab3497838132fb1bbd293f4054 upstream. Akira-san has been reporting rare deadlocks of his machine when running xfstests test 269 on ext4 filesystem. The problem turned out to be in ext4_da_reserve_metadata() and ext4_da_reserve_space() which called ext4_should_retry_alloc() while holding i_data_sem. Since ext4_should_retry_alloc() can force a transaction commit, this is a lock ordering violation and leads to deadlocks. Fix the problem by just removing the retry loops. These functions should just report ENOSPC to the caller (e.g. ext4_da_write_begin()) and that function must take care of retrying after dropping all necessary locks. Reported-and-tested-by: Akira Fujita Reviewed-by: Zheng Liu Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o" [ kamal: backport to 3.8 (no ext4_da_reserve_metadata) ] Cc: Kamal Mostafa Signed-off-by: Luis Henriques --- fs/ext4/inode.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 8aacdda..efecfb7 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1175,7 +1175,6 @@ static int ext4_journalled_write_end(struct file *file, */ static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock) { - int retries = 0; struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); struct ext4_inode_info *ei = EXT4_I(inode); unsigned int md_needed; @@ -1197,7 +1196,6 @@ static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock) * in order to allocate nrblocks * worse case is one extent per block */ -repeat: spin_lock(&ei->i_block_reservation_lock); /* * ext4_calc_metadata_amount() has side effects, which we have @@ -1217,10 +1215,6 @@ repeat: ei->i_da_metadata_calc_len = save_len; ei->i_da_metadata_calc_last_lblock = save_last_lblock; spin_unlock(&ei->i_block_reservation_lock); - if (ext4_should_retry_alloc(inode->i_sb, &retries)) { - yield(); - goto repeat; - } dquot_release_reservation_block(inode, EXT4_C2B(sbi, 1)); return -ENOSPC; } -- 1.8.3.2 -- 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/