This is a note to let you know that I've just added the patch titled
ext4: fix stripe-unaligned allocations
to the 3.18-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-fix-stripe-unaligned-allocations.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Nov 6 10:42:09 CET 2017
From: Jan Kara <jack@xxxxxxx>
Date: Sat, 7 Oct 2017 22:37:59 +0000
Subject: ext4: fix stripe-unaligned allocations
From: Jan Kara <jack@xxxxxxx>
[ Upstream commit d9b22cf9f5466a057f2a4f1e642b469fa9d73117 ]
When a filesystem is created using:
mkfs.ext4 -b 4096 -E stride=512 <dev>
and we try to allocate 64MB extent, we will end up directly in
ext4_mb_complex_scan_group(). This is because the request is detected
as power-of-two allocation (so we start in ext4_mb_regular_allocator()
with ac_criteria == 0) however the check before
ext4_mb_simple_scan_group() refuses the direct buddy scan because the
allocation request is too large. Since cr == 0, the check whether we
should use ext4_mb_scan_aligned() fails as well and we fall back to
ext4_mb_complex_scan_group().
Fix the problem by checking for upper limit on power-of-two requests
directly when detecting them.
Reported-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/mballoc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2113,8 +2113,10 @@ ext4_mb_regular_allocator(struct ext4_al
* We search using buddy data only if the order of the request
* is greater than equal to the sbi_s_mb_order2_reqs
* You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
+ * We also support searching for power-of-two requests only for
+ * requests upto maximum buddy size we have constructed.
*/
- if (i >= sbi->s_mb_order2_reqs) {
+ if (i >= sbi->s_mb_order2_reqs && i <= sb->s_blocksize_bits + 2) {
/*
* This should tell if fe_len is exactly power of 2
*/
@@ -2176,7 +2178,7 @@ repeat:
}
ac->ac_groups_scanned++;
- if (cr == 0 && ac->ac_2order < sb->s_blocksize_bits+2)
+ if (cr == 0)
ext4_mb_simple_scan_group(ac, &e4b);
else if (cr == 1 && sbi->s_stripe &&
!(ac->ac_g_ex.fe_len % sbi->s_stripe))
Patches currently in stable-queue which might be from jack@xxxxxxx are
queue-3.18/ext4-fix-stripe-unaligned-allocations.patch
queue-3.18/ext4-do-not-use-stripe_width-if-it-is-not-set.patch