From 74a52716ec24751ee326a67527b588f730caf35d Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Tue, 3 Feb 2026 18:03:35 +0000 Subject: [PATCH] btrfs: use the correct type to initialize block reserve for delayed refs [ Upstream commit 2155d0c0a761a56ce7ede83a26eb23ea0f935260 ] When initializing the delayed refs block reserve for a transaction handle we are passing a type of BTRFS_BLOCK_RSV_DELOPS, which is meant for delayed items and not for delayed refs. The correct type for delayed refs is BTRFS_BLOCK_RSV_DELREFS. On release of any excess space reserved in a local delayed refs reserve, we also should transfer that excess space to the global block reserve (it it's full, we return to the space info for general availability). By initializing a transaction's local delayed refs block reserve with a type of BTRFS_BLOCK_RSV_DELOPS, we were also causing any excess space released from the delayed block reserve (fs_info->delayed_block_rsv, used for delayed inodes and items) to be transferred to the global block reserve instead of the global delayed refs block reserve. This was an unintentional change in commit 28270e25c69a ("btrfs: always reserve space for delayed refs when starting transaction"), but it's not particularly serious as things tend to cancel out each other most of the time and it's relatively rare to be anywhere near exhaustion of the global reserve. Fix this by initializing a transaction's local delayed refs reserve with a type of BTRFS_BLOCK_RSV_DELREFS and making btrfs_block_rsv_release() attempt to transfer unused space from such a reserve into the global block reserve, just as we did before that commit for when the block reserve is a delayed refs rsv. Reported-by: Alex Lyakas Link: https://lore.kernel.org/linux-btrfs/CAOcd+r0FHG5LWzTSu=LknwSoqxfw+C00gFAW7fuX71+Z5AfEew@mail.gmail.com/ Fixes: 28270e25c69a ("btrfs: always reserve space for delayed refs when starting transaction") Reviewed-by: Alex Lyakas Signed-off-by: Filipe Manana Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/block-rsv.c | 7 ++++--- fs/btrfs/transaction.c | 2 +- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/block-rsv.c b/fs/btrfs/block-rsv.c index a07b9594dc70..a578bd3b32bb 100644 --- a/fs/btrfs/block-rsv.c +++ b/fs/btrfs/block-rsv.c @@ -280,10 +280,11 @@ u64 btrfs_block_rsv_release(struct btrfs_fs_info *fs_info, struct btrfs_block_rsv *target = NULL; /* - * If we are a delayed block reserve then push to the global rsv, - * otherwise dump into the global delayed reserve if it is not full. + * If we are a delayed refs block reserve then push to the global + * reserve, otherwise dump into the global delayed refs reserve if it is + * not full. */ - if (block_rsv->type == BTRFS_BLOCK_RSV_DELOPS) + if (block_rsv->type == BTRFS_BLOCK_RSV_DELREFS) target = global_rsv; else if (block_rsv != global_rsv && !btrfs_block_rsv_full(delayed_rsv)) target = delayed_rsv; diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index b7679f339940..0ee6b40af65e 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -726,7 +726,7 @@ again: h->type = type; INIT_LIST_HEAD(&h->new_bgs); - btrfs_init_metadata_block_rsv(fs_info, &h->delayed_rsv, BTRFS_BLOCK_RSV_DELOPS); + btrfs_init_metadata_block_rsv(fs_info, &h->delayed_rsv, BTRFS_BLOCK_RSV_DELREFS); smp_mb(); if (cur_trans->state >= TRANS_STATE_COMMIT_START &&