The patch below does not apply to the 4.14-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 <stable@xxxxxxxxxxxxxxx>. 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-4.14.y git checkout FETCH_HEAD git cherry-pick -x 5d5460fa7932bed3a9082a6a8852cfbdb46acbe8 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023072441-deprive-glimpse-b891@gregkh' --subject-prefix 'PATCH 4.14.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 <ojaswin@xxxxxxxxxxxxx> 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 Cc: stable@xxxxxxxxxx Fixes: 33122aa930 ("ext4: Add allocation criteria 1.5 (CR1_5)") Signed-off-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230609103403.112807-1-ojaswin@xxxxxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index a2475b8c9fb5..456150ef6111 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -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; /*
