This is a note to let you know that I've just added the patch titled
ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: ext4-handle-the-rest-of-ext4_mb_load_buddy-enomem-errors.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Mon Apr 9 17:09:24 CEST 2018
From: Konstantin Khlebnikov khlebnikov@yandex-team.ru Date: Sun, 21 May 2017 22:35:23 -0400 Subject: ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors
From: Konstantin Khlebnikov khlebnikov@yandex-team.ru
[ Upstream commit 9651e6b2e20648d04d5e1fe6479a3056047e8781 ]
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()
Fixes: adb7ef600cc9 ("ext4: use __GFP_NOFAIL in ext4_free_blocks()") Signed-off-by: Konstantin Khlebnikov khlebnikov@yandex-team.ru Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ext4/mballoc.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-)
--- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -3877,7 +3877,8 @@ ext4_mb_discard_group_preallocations(str
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; } @@ -4034,10 +4035,11 @@ repeat: 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; }
@@ -4293,11 +4295,14 @@ ext4_mb_discard_lg_preallocations(struct 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); @@ -5117,8 +5122,8 @@ ext4_trim_all_free(struct super_block *s
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;
Patches currently in stable-queue which might be from khlebnikov@yandex-team.ru are
queue-4.9/ext4-handle-the-rest-of-ext4_mb_load_buddy-enomem-errors.patch