4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;