From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id 5C406831F4 for ; Fri, 19 May 2017 03:09:59 -0400 (EDT) Received: by mail-wm0-f71.google.com with SMTP id x184so13303183wmf.14 for ; Fri, 19 May 2017 00:09:59 -0700 (PDT) Received: from forwardcorp1j.cmail.yandex.net (forwardcorp1j.cmail.yandex.net. [2a02:6b8:0:1630::180]) by mx.google.com with ESMTPS id g90si2407250lfi.43.2017.05.19.00.09.57 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 19 May 2017 00:09:57 -0700 (PDT) Subject: [PATCH] ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors From: Konstantin Khlebnikov Date: Fri, 19 May 2017 10:09:54 +0300 Message-ID: <149517779388.33359.16474190951431954772.stgit@buzz> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andreas Dilger , linux-ext4@vger.kernel.org, Theodore Ts'o , linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org I've got another report about breaking ext4 by ENOMEM error returned from ext4_mb_load_buddy() caused by memory shortage in memory cgroup. This time inside ext4_discard_preallocations(). This patch replaces ext4_error() with ext4_warning() where errors returned from ext4_mb_load_buddy() are not fatal and handled by caller: * ext4_mb_discard_group_preallocations() - called before generating ENOSPC, we'll try to discard other group or return ENOSPC into user-space. * ext4_trim_all_free() - just stop trimming and return ENOMEM from ioctl. Some callers cannot handle errors, thus __GFP_NOFAIL is used for them: * ext4_discard_preallocations() * ext4_mb_discard_lg_preallocations() The only unclear case is ext4_group_add_blocks(), probably ext4_std_error() should handle ENOMEM as warning and don't break filesystem. Fixes: adb7ef600cc9 ("ext4: use __GFP_NOFAIL in ext4_free_blocks()") Signed-off-by: Konstantin Khlebnikov --- fs/ext4/mballoc.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 5083bce20ac4..b7928cddd539 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3887,7 +3887,8 @@ ext4_mb_discard_group_preallocations(struct super_block *sb, err = ext4_mb_load_buddy(sb, group, &e4b); if (err) { - ext4_error(sb, "Error loading buddy information for %u", group); + ext4_warning(sb, "Error %d loading buddy information for %u", + err, group); put_bh(bitmap_bh); return 0; } @@ -4044,10 +4045,11 @@ void ext4_discard_preallocations(struct inode *inode) BUG_ON(pa->pa_type != MB_INODE_PA); group = ext4_get_group_number(sb, pa->pa_pstart); - err = ext4_mb_load_buddy(sb, group, &e4b); + err = ext4_mb_load_buddy_gfp(sb, group, &e4b, + GFP_NOFS|__GFP_NOFAIL); if (err) { - ext4_error(sb, "Error loading buddy information for %u", - group); + ext4_error(sb, "Error %d loading buddy information for %u", + err, group); continue; } @@ -4303,11 +4305,14 @@ ext4_mb_discard_lg_preallocations(struct super_block *sb, spin_unlock(&lg->lg_prealloc_lock); list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) { + int err; group = ext4_get_group_number(sb, pa->pa_pstart); - if (ext4_mb_load_buddy(sb, group, &e4b)) { - ext4_error(sb, "Error loading buddy information for %u", - group); + err = ext4_mb_load_buddy_gfp(sb, group, &e4b, + GFP_NOFS|__GFP_NOFAIL); + if (err) { + ext4_error(sb, "Error %d loading buddy information for %u", + err, group); continue; } ext4_lock_group(sb, group); @@ -5127,8 +5132,8 @@ ext4_trim_all_free(struct super_block *sb, ext4_group_t group, ret = ext4_mb_load_buddy(sb, group, &e4b); if (ret) { - ext4_error(sb, "Error in loading buddy " - "information for %u", group); + ext4_warning(sb, "Error %d loading buddy information for %u", + ret, group); return ret; } bitmap = e4b.bd_bitmap; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org