This is a note to let you know that I've just added the patch titled
ext4: replace open coded nofail allocation in ext4_free_blocks()
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-replace-open-coded-nofail-allocation-in-ext4_free_blocks.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7444a072c387a93ebee7066e8aee776954ab0e41 Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@xxxxxxx>
Date: Sun, 5 Jul 2015 12:33:44 -0400
Subject: ext4: replace open coded nofail allocation in ext4_free_blocks()
From: Michal Hocko <mhocko@xxxxxxx>
commit 7444a072c387a93ebee7066e8aee776954ab0e41 upstream.
ext4_free_blocks is looping around the allocation request and mimics
__GFP_NOFAIL behavior without any allocation fallback strategy. Let's
remove the open coded loop and replace it with __GFP_NOFAIL. Without the
flag the allocator has no way to find out never-fail requirement and
cannot help in any way.
Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/mballoc.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4800,18 +4800,12 @@ do_more:
/*
* blocks being freed are metadata. these blocks shouldn't
* be used until this transaction is committed
+ *
+ * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
+ * to fail.
*/
- retry:
- new_entry = kmem_cache_alloc(ext4_free_data_cachep, GFP_NOFS);
- if (!new_entry) {
- /*
- * We use a retry loop because
- * ext4_free_blocks() is not allowed to fail.
- */
- cond_resched();
- congestion_wait(BLK_RW_ASYNC, HZ/50);
- goto retry;
- }
+ new_entry = kmem_cache_alloc(ext4_free_data_cachep,
+ GFP_NOFS|__GFP_NOFAIL);
new_entry->efd_start_cluster = bit;
new_entry->efd_group = block_group;
new_entry->efd_count = count_clusters;
Patches currently in stable-queue which might be from mhocko@xxxxxxx are
queue-4.1/ext4-replace-open-coded-nofail-allocation-in-ext4_free_blocks.patch
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