+ btrfs-set-as_kernel_file-on-the-btree_inode.patch added to mm-new branch

+ btrfs-set-as_kernel_file-on-the-btree_inode.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: btrfs: set AS_KERNEL_FILE on the btree_inode
has been added to the -mm mm-new branch.  Its filename is
     btrfs-set-as_kernel_file-on-the-btree_inode.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/btrfs-set-as_kernel_file-on-the-btree_inode.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

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------------------------------------------------------
From: Boris Burkov <boris@bur.io>
Subject: btrfs: set AS_KERNEL_FILE on the btree_inode
Date: Thu, 21 Aug 2025 14:55:37 -0700

extent_buffers are global and shared so their pages should not belong to
any particular cgroup (currently whichever cgroups happens to allocate the
extent_buffer).

Btrfs tree operations should not arbitrarily block on cgroup reclaim or
have the shared extent_buffer pages on a cgroup's reclaim lists.

Link: https://lkml.kernel.org/r/2ee99832619a3fdfe80bf4dc9760278662d2d746.1755812945.git.boris@bur.io
Signed-off-by: Boris Burkov <boris@bur.io>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Tested-by: syzbot@syzkaller.appspotmail.com
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Qu Wenruo <wqu@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/btrfs/disk-io.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/btrfs/disk-io.c~btrfs-set-as_kernel_file-on-the-btree_inode
+++ a/fs/btrfs/disk-io.c
@@ -1930,6 +1930,7 @@ static int btrfs_init_btree_inode(struct
 	BTRFS_I(inode)->root = btrfs_grab_root(fs_info->tree_root);
 	set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
 	__insert_inode_hash(inode, hash);
+	set_bit(AS_KERNEL_FILE, &inode->i_mapping->flags);
 	fs_info->btree_inode = inode;
 
 	return 0;
_

Patches currently in -mm which might be from boris@bur.io are

mm-filemap-add-as_kernel_file.patch
mm-filemap-add-as_kernel_file-fix.patch
mm-add-vmstat-for-kernel_file-pages.patch
btrfs-set-as_kernel_file-on-the-btree_inode.patch