From nobody Sun Feb 8 10:44:22 2026 Received: from mail-m49198.qiye.163.com (mail-m49198.qiye.163.com [45.254.49.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 52A7D332EAA; Fri, 16 Jan 2026 14:28:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.254.49.198 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768573735; cv=none; b=RqUgIqNWozyZ5YI19vYfmiY2RYax8AqDU4Bu+y17GnSZeluebwFTMKGNOhYTJH4t1982eXLUFF1sIObpFy3w9ztxDsBFb3JRqfYUqg2GLoJCHJt866fbg2kIrGnhadIqMoRQAg0WjSteWFEUblhP5sLbzWkyzmaYjzent7HwfiQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768573735; c=relaxed/simple; bh=Hc+pmX+YG1JfhJcGFa0KQuoVXAK1vkPo/8xVqXo6HjA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AVCoJjncv/xur2iJqD+i534mSvj2U5+FOh2zj5rc9vMRIow0HgCgTy6EEIJtnggkV9V2SfwtmnY54Pd0Lyo+6Fvpang1QktKwwiiLbFHjgsXoczaFmrJYXA2BBKoYtmLRSg0P0Oegz2E8PdEKtuX4tLhkAhSn0n77TwelX2Iz4w= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ustc.edu; spf=pass smtp.mailfrom=ustc.edu; arc=none smtp.client-ip=45.254.49.198 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ustc.edu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ustc.edu Received: from localhost (unknown [14.22.11.164]) by smtp.qiye.163.com (Hmail) with ESMTP id 30ef1dc9d; Fri, 16 Jan 2026 22:28:48 +0800 (GMT+08:00) From: Chunsheng Luo To: miklos@szeredi.hu Cc: amir73il@gmail.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Chunsheng Luo Subject: [PATCH 1/2] fuse: add ioctl to cleanup all backing files Date: Fri, 16 Jan 2026 22:28:44 +0800 Message-ID: <20260116142845.422-2-luochunsheng@ustc.edu> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260116142845.422-1-luochunsheng@ustc.edu> References: <20260116142845.422-1-luochunsheng@ustc.edu> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Tid: 0a9bc735771303a2kunm2ada7c83268fe7 X-HM-MType: 10 X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVlDGU9NVksdSUkaGksfQxkeS1YeHw5VEwETFhoSFy QUDg9ZV1kYEgtZQVlKT1VJSVVKSlVKTU9ZV1kWGg8SFR0UWUFZT0tIVUpLSUJDQ0xVSktLVUtZBg ++ Content-Type: text/plain; charset="utf-8" To simplify crash recovery and reduce performance impact, backing_ids are not persisted across daemon restarts. After crash recovery, this may lead to resource leaks if backing file resources are not properly cleaned up. Add FUSE_DEV_IOC_BACKING_CLOSE_ALL ioctl to release all backing_ids and put backing files. When the FUSE daemon restarts, it can use this ioctl to cleanup all backing file resources. Signed-off-by: Chunsheng Luo Reviewed-by: Amir Goldstein --- fs/fuse/backing.c | 19 +++++++++++++++++++ fs/fuse/dev.c | 16 ++++++++++++++++ fs/fuse/fuse_i.h | 1 + include/uapi/linux/fuse.h | 1 + 4 files changed, 37 insertions(+) diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c index 4afda419dd14..e93d797a2cde 100644 --- a/fs/fuse/backing.c +++ b/fs/fuse/backing.c @@ -166,6 +166,25 @@ int fuse_backing_close(struct fuse_conn *fc, int backi= ng_id) return err; } =20 +static int fuse_backing_close_one(int id, void *p, void *data) +{ + struct fuse_conn *fc =3D data; + + fuse_backing_close(fc, id); + + return 0; +} + +int fuse_backing_close_all(struct fuse_conn *fc) +{ + if (!fc->passthrough || !capable(CAP_SYS_ADMIN)) + return -EPERM; + + idr_for_each(&fc->backing_files_map, fuse_backing_close_one, fc); + + return 0; +} + struct fuse_backing *fuse_backing_lookup(struct fuse_conn *fc, int backing= _id) { struct fuse_backing *fb; diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 6d59cbc877c6..f05d55302598 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -2654,6 +2654,19 @@ static long fuse_dev_ioctl_backing_close(struct file= *file, __u32 __user *argp) return fuse_backing_close(fud->fc, backing_id); } =20 +static long fuse_dev_ioctl_backing_close_all(struct file *file) +{ + struct fuse_dev *fud =3D fuse_get_dev(file); + + if (IS_ERR(fud)) + return PTR_ERR(fud); + + if (!IS_ENABLED(CONFIG_FUSE_PASSTHROUGH)) + return -EOPNOTSUPP; + + return fuse_backing_close_all(fud->fc); +} + static long fuse_dev_ioctl_sync_init(struct file *file) { int err =3D -EINVAL; @@ -2682,6 +2695,9 @@ static long fuse_dev_ioctl(struct file *file, unsigne= d int cmd, case FUSE_DEV_IOC_BACKING_CLOSE: return fuse_dev_ioctl_backing_close(file, argp); =20 + case FUSE_DEV_IOC_BACKING_CLOSE_ALL: + return fuse_dev_ioctl_backing_close_all(file); + case FUSE_DEV_IOC_SYNC_INIT: return fuse_dev_ioctl_sync_init(file); =20 diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 7f16049387d1..33e91a5d3765 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -1573,6 +1573,7 @@ void fuse_backing_files_init(struct fuse_conn *fc); void fuse_backing_files_free(struct fuse_conn *fc); int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map); int fuse_backing_close(struct fuse_conn *fc, int backing_id); +int fuse_backing_close_all(struct fuse_conn *fc); =20 /* passthrough.c */ static inline struct fuse_backing *fuse_inode_backing(struct fuse_inode *f= i) diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index c13e1f9a2f12..e4ff28a4ff40 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -1139,6 +1139,7 @@ struct fuse_backing_map { struct fuse_backing_map) #define FUSE_DEV_IOC_BACKING_CLOSE _IOW(FUSE_DEV_IOC_MAGIC, 2, uint32_t) #define FUSE_DEV_IOC_SYNC_INIT _IO(FUSE_DEV_IOC_MAGIC, 3) +#define FUSE_DEV_IOC_BACKING_CLOSE_ALL _IO(FUSE_DEV_IOC_MAGIC, 4) =20 struct fuse_lseek_in { uint64_t fh; --=20 2.43.0 From nobody Sun Feb 8 10:44:22 2026 Received: from mail-m155101.qiye.163.com (mail-m155101.qiye.163.com [101.71.155.101]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A04631A555; 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dmarc=pass (p=none dis=none) header.from=ustc.edu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ustc.edu Received: from localhost (unknown [14.22.11.163]) by smtp.qiye.163.com (Hmail) with ESMTP id 30ef1dc9f; Fri, 16 Jan 2026 22:28:49 +0800 (GMT+08:00) From: Chunsheng Luo To: miklos@szeredi.hu Cc: amir73il@gmail.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Chunsheng Luo Subject: [PATCH 2/2] fuse: Relax backing file validation to compare backing inodes Date: Fri, 16 Jan 2026 22:28:45 +0800 Message-ID: <20260116142845.422-3-luochunsheng@ustc.edu> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260116142845.422-1-luochunsheng@ustc.edu> References: <20260116142845.422-1-luochunsheng@ustc.edu> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Tid: 0a9bc7357c5b03a2kunm62945613268fec X-HM-MType: 10 X-HM-Spam-Status: e1kfGhgUHx5ZQUtXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVkaTU1IVh4eGkMYGUpNGEwdS1YeHw5VEwETFhoSFy QUDg9ZV1kYEgtZQVlKT1VJSVVKSlVKTUhZV1kWGg8SFR0UWUFZS1VLVUtVS1kG Content-Type: text/plain; charset="utf-8" To simplify crash recovery and reduce performance impact, backing_ids are not persisted across daemon restarts. However, when the daemon restarts and another process open the same FUSE file and assigning it the same backing file (with the same inode) will also cause the fuse_inode_uncached_io_start() function to fail due to a mismatch in the fb pointer. So Relax the validation in fuse_inode_uncached_io_start() to compare backing inodes instead of fuse_backing pointers. Signed-off-by: Chunsheng Luo Reviewed-by: Amir Goldstein --- fs/fuse/iomode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fuse/iomode.c b/fs/fuse/iomode.c index 3728933188f3..ca7619958b0d 100644 --- a/fs/fuse/iomode.c +++ b/fs/fuse/iomode.c @@ -90,7 +90,7 @@ int fuse_inode_uncached_io_start(struct fuse_inode *fi, s= truct fuse_backing *fb) spin_lock(&fi->lock); /* deny conflicting backing files on same fuse inode */ oldfb =3D fuse_inode_backing(fi); - if (fb && oldfb && oldfb !=3D fb) { + if (fb && oldfb && file_inode(oldfb->file) !=3D file_inode(fb->file)) { err =3D -EBUSY; goto unlock; } --=20 2.43.0