FAILED: patch "[PATCH] ext4: fix off by one issue in" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 5d5460fa7932bed3a9082a6a8852cfbdb46acbe8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023072412-raft-circle-8700@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

5d5460fa7932 ("ext4: fix off by one issue in ext4_mb_choose_next_group_best_avail()") f52f3d2b9fba ("ext4: Give symbolic names to mballoc criterias")
7e170922f06b ("ext4: Add allocation criteria 1.5 (CR1_5)")
1b4200112108 ("ext4: Avoid scanning smaller extents in BG during CR1") 3ef5d2638796 ("ext4: Add counter to track successful allocation of goal length") fdd9a00943a5 ("ext4: Add per CR extent scanned counter")
4eb7a4a1a33b ("ext4: Convert mballoc cr (criteria) to enum")
c3defd99d58c ("ext4: treat stripe in block unit")
361eb69fc99f ("ext4: Remove the logic to trim inode PAs")
3872778664e3 ("ext4: Use rbtrees to manage PAs instead of inode i_prealloc_list") a8e38fd37cff ("ext4: Convert pa->pa_inode_list and pa->pa_obj_lock into a union") 93cdf49f6eca ("ext4: Fix best extent lstart adjustment logic in ext4_mb_new_inode_pa()") 0830344c953a ("ext4: Abstract out overlap fix/check logic in ext4_mb_normalize_request()") 7692094ac513 ("ext4: Move overlap assert logic into a separate function") bcf434992145 ("ext4: Refactor code in ext4_mb_normalize_request() and ext4_mb_use_preallocated()") e86a718228b6 ("ext4: Stop searching if PA doesn't satisfy non-extent file") 91a48aaf59d0 ("ext4: avoid unnecessary pointer dereference in ext4_mb_normalize_request") 83e80a6e3543 ("ext4: use buckets for cr 1 block scan instead of rbtree") 4fca50d440cc ("ext4: make mballoc try target group first even with mb_optimize_scan") cf4ff938b47f ("ext4: correct the judgment of BUG in ext4_mb_normalize_request")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5d5460fa7932bed3a9082a6a8852cfbdb46acbe8 Mon Sep 17 00:00:00 2001
From: Ojaswin Mujoo <[email protected]>
Date: Fri, 9 Jun 2023 16:04:03 +0530
Subject: [PATCH] ext4: fix off by one issue in
ext4_mb_choose_next_group_best_avail()

In ext4_mb_choose_next_group_best_avail(), we want the start order to be 1 less than goal length and the min_order to be, at max, 1 more than the original length. This commit fixes an off by one issue that arose due to the fact that 1 << fls(n) > (n).

After all the processing:

order = 1 order below goal len
min_order = maximum of the three:-
- order - trim_order
- 1 order below B2C(s_stripe)
- 1 order above original len

index a2475b8c9fb5..456150ef6111 100644
@@ -1006,14 +1006,11 @@ static void ext4_mb_choose_next_group_best_avail(struct ext4_allocation_context
 	 * fls() instead since we need to know the actual length while modifying
 	 * goal length.
 	 */
-	order = fls(ac->ac_g_ex.fe_len);
+	order = fls(ac->ac_g_ex.fe_len) - 1;
 	min_order = order - sbi->s_mb_best_avail_max_trim_order;
 	if (min_order < 0)
 		min_order = 0;
 
-	if (1 << min_order < ac->ac_o_ex.fe_len)
-		min_order = fls(ac->ac_o_ex.fe_len) + 1;
-
 	if (sbi->s_stripe > 0) {
 		/*
 		 * We are assuming that stripe size is always a multiple of

@@ -1021,9 +1018,16 @@ static void ext4_mb_choose_next_group_best_avail(struct ext4_allocation_context
 		 */
 		num_stripe_clusters = EXT4_NUM_B2C(sbi, sbi->s_stripe);
 		if (1 << min_order < num_stripe_clusters)
-			min_order = fls(num_stripe_clusters);
+			/*
+			 * We consider 1 order less because later we round
+			 * up the goal len to num_stripe_clusters
+			 */
+			min_order = fls(num_stripe_clusters) - 1;
 	}
 
+	if (1 << min_order < ac->ac_o_ex.fe_len)
+		min_order = fls(ac->ac_o_ex.fe_len);
+
 	for (i = order; i >= min_order; i--) {
 		int frag_order;
 		/*