fuse: move the backing file idr and code into a new source file
iomap support for fuse is also going to want the ability to attach backing files to a fuse filesystem. Move the fuse_backing code into a separate file so that both can use it. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Darrick J. Wong
Miklos Szeredi
parent
d3906d8f3c
commit
c4331e19a6
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@ -13,7 +13,7 @@ obj-$(CONFIG_VIRTIO_FS) += virtiofs.o
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fuse-y := dev.o dir.o file.o inode.o control.o xattr.o acl.o readdir.o ioctl.o
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fuse-y += iomode.o
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fuse-$(CONFIG_FUSE_DAX) += dax.o
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fuse-$(CONFIG_FUSE_PASSTHROUGH) += passthrough.o
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fuse-$(CONFIG_FUSE_PASSTHROUGH) += passthrough.o backing.o
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fuse-$(CONFIG_SYSCTL) += sysctl.o
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fuse-$(CONFIG_FUSE_IO_URING) += dev_uring.o
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@ -0,0 +1,179 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* FUSE passthrough to backing file.
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*
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* Copyright (c) 2023 CTERA Networks.
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*/
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#include "fuse_i.h"
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#include <linux/file.h>
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struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
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{
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if (fb && refcount_inc_not_zero(&fb->count))
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return fb;
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return NULL;
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}
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static void fuse_backing_free(struct fuse_backing *fb)
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{
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pr_debug("%s: fb=0x%p\n", __func__, fb);
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if (fb->file)
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fput(fb->file);
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put_cred(fb->cred);
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kfree_rcu(fb, rcu);
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}
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void fuse_backing_put(struct fuse_backing *fb)
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{
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if (fb && refcount_dec_and_test(&fb->count))
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fuse_backing_free(fb);
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}
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void fuse_backing_files_init(struct fuse_conn *fc)
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{
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idr_init(&fc->backing_files_map);
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}
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static int fuse_backing_id_alloc(struct fuse_conn *fc, struct fuse_backing *fb)
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{
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int id;
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idr_preload(GFP_KERNEL);
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spin_lock(&fc->lock);
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/* FIXME: xarray might be space inefficient */
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id = idr_alloc_cyclic(&fc->backing_files_map, fb, 1, 0, GFP_ATOMIC);
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spin_unlock(&fc->lock);
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idr_preload_end();
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WARN_ON_ONCE(id == 0);
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return id;
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}
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static struct fuse_backing *fuse_backing_id_remove(struct fuse_conn *fc,
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int id)
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{
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struct fuse_backing *fb;
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spin_lock(&fc->lock);
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fb = idr_remove(&fc->backing_files_map, id);
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spin_unlock(&fc->lock);
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return fb;
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}
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static int fuse_backing_id_free(int id, void *p, void *data)
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{
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struct fuse_backing *fb = p;
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WARN_ON_ONCE(refcount_read(&fb->count) != 1);
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fuse_backing_free(fb);
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return 0;
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}
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void fuse_backing_files_free(struct fuse_conn *fc)
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{
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idr_for_each(&fc->backing_files_map, fuse_backing_id_free, NULL);
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idr_destroy(&fc->backing_files_map);
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}
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int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map)
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{
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struct file *file;
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struct super_block *backing_sb;
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struct fuse_backing *fb = NULL;
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int res;
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pr_debug("%s: fd=%d flags=0x%x\n", __func__, map->fd, map->flags);
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/* TODO: relax CAP_SYS_ADMIN once backing files are visible to lsof */
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res = -EPERM;
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if (!fc->passthrough || !capable(CAP_SYS_ADMIN))
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goto out;
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res = -EINVAL;
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if (map->flags || map->padding)
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goto out;
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file = fget_raw(map->fd);
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res = -EBADF;
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if (!file)
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goto out;
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/* read/write/splice/mmap passthrough only relevant for regular files */
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res = d_is_dir(file->f_path.dentry) ? -EISDIR : -EINVAL;
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if (!d_is_reg(file->f_path.dentry))
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goto out_fput;
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backing_sb = file_inode(file)->i_sb;
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res = -ELOOP;
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if (backing_sb->s_stack_depth >= fc->max_stack_depth)
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goto out_fput;
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fb = kmalloc(sizeof(struct fuse_backing), GFP_KERNEL);
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res = -ENOMEM;
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if (!fb)
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goto out_fput;
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fb->file = file;
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fb->cred = prepare_creds();
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refcount_set(&fb->count, 1);
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res = fuse_backing_id_alloc(fc, fb);
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if (res < 0) {
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fuse_backing_free(fb);
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fb = NULL;
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}
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out:
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pr_debug("%s: fb=0x%p, ret=%i\n", __func__, fb, res);
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return res;
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out_fput:
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fput(file);
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goto out;
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}
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int fuse_backing_close(struct fuse_conn *fc, int backing_id)
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{
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struct fuse_backing *fb = NULL;
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int err;
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pr_debug("%s: backing_id=%d\n", __func__, backing_id);
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/* TODO: relax CAP_SYS_ADMIN once backing files are visible to lsof */
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err = -EPERM;
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if (!fc->passthrough || !capable(CAP_SYS_ADMIN))
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goto out;
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err = -EINVAL;
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if (backing_id <= 0)
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goto out;
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err = -ENOENT;
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fb = fuse_backing_id_remove(fc, backing_id);
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if (!fb)
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goto out;
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fuse_backing_put(fb);
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err = 0;
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out:
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pr_debug("%s: fb=0x%p, err=%i\n", __func__, fb, err);
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return err;
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}
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struct fuse_backing *fuse_backing_lookup(struct fuse_conn *fc, int backing_id)
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{
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struct fuse_backing *fb;
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rcu_read_lock();
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fb = idr_find(&fc->backing_files_map, backing_id);
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fb = fuse_backing_get(fb);
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rcu_read_unlock();
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return fb;
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}
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@ -1529,6 +1529,33 @@ struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
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void fuse_file_release(struct inode *inode, struct fuse_file *ff,
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unsigned int open_flags, fl_owner_t id, bool isdir);
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/* backing.c */
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#ifdef CONFIG_FUSE_PASSTHROUGH
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struct fuse_backing *fuse_backing_get(struct fuse_backing *fb);
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void fuse_backing_put(struct fuse_backing *fb);
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struct fuse_backing *fuse_backing_lookup(struct fuse_conn *fc, int backing_id);
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#else
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static inline struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
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{
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return NULL;
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}
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static inline void fuse_backing_put(struct fuse_backing *fb)
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{
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}
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static inline struct fuse_backing *fuse_backing_lookup(struct fuse_conn *fc,
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int backing_id)
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{
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return NULL;
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}
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#endif
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void fuse_backing_files_init(struct fuse_conn *fc);
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void fuse_backing_files_free(struct fuse_conn *fc);
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int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map);
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int fuse_backing_close(struct fuse_conn *fc, int backing_id);
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/* passthrough.c */
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static inline struct fuse_backing *fuse_inode_backing(struct fuse_inode *fi)
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{
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@ -1549,26 +1576,6 @@ static inline struct fuse_backing *fuse_inode_backing_set(struct fuse_inode *fi,
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#endif
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}
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#ifdef CONFIG_FUSE_PASSTHROUGH
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struct fuse_backing *fuse_backing_get(struct fuse_backing *fb);
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void fuse_backing_put(struct fuse_backing *fb);
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#else
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static inline struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
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{
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return NULL;
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}
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static inline void fuse_backing_put(struct fuse_backing *fb)
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{
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}
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#endif
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void fuse_backing_files_init(struct fuse_conn *fc);
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void fuse_backing_files_free(struct fuse_conn *fc);
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int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map);
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int fuse_backing_close(struct fuse_conn *fc, int backing_id);
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struct fuse_backing *fuse_passthrough_open(struct file *file, int backing_id);
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void fuse_passthrough_release(struct fuse_file *ff, struct fuse_backing *fb);
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@ -144,163 +144,6 @@ ssize_t fuse_passthrough_mmap(struct file *file, struct vm_area_struct *vma)
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return backing_file_mmap(backing_file, vma, &ctx);
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}
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struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
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{
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if (fb && refcount_inc_not_zero(&fb->count))
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return fb;
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return NULL;
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}
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static void fuse_backing_free(struct fuse_backing *fb)
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{
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pr_debug("%s: fb=0x%p\n", __func__, fb);
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if (fb->file)
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fput(fb->file);
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put_cred(fb->cred);
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kfree_rcu(fb, rcu);
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}
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void fuse_backing_put(struct fuse_backing *fb)
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{
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if (fb && refcount_dec_and_test(&fb->count))
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fuse_backing_free(fb);
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}
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void fuse_backing_files_init(struct fuse_conn *fc)
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{
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idr_init(&fc->backing_files_map);
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}
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static int fuse_backing_id_alloc(struct fuse_conn *fc, struct fuse_backing *fb)
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{
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int id;
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idr_preload(GFP_KERNEL);
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spin_lock(&fc->lock);
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/* FIXME: xarray might be space inefficient */
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id = idr_alloc_cyclic(&fc->backing_files_map, fb, 1, 0, GFP_ATOMIC);
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spin_unlock(&fc->lock);
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idr_preload_end();
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WARN_ON_ONCE(id == 0);
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return id;
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}
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static struct fuse_backing *fuse_backing_id_remove(struct fuse_conn *fc,
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int id)
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{
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struct fuse_backing *fb;
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spin_lock(&fc->lock);
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fb = idr_remove(&fc->backing_files_map, id);
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spin_unlock(&fc->lock);
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return fb;
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}
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static int fuse_backing_id_free(int id, void *p, void *data)
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{
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struct fuse_backing *fb = p;
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WARN_ON_ONCE(refcount_read(&fb->count) != 1);
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fuse_backing_free(fb);
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return 0;
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}
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void fuse_backing_files_free(struct fuse_conn *fc)
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{
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idr_for_each(&fc->backing_files_map, fuse_backing_id_free, NULL);
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idr_destroy(&fc->backing_files_map);
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}
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int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map)
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{
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struct file *file;
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struct super_block *backing_sb;
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struct fuse_backing *fb = NULL;
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int res;
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pr_debug("%s: fd=%d flags=0x%x\n", __func__, map->fd, map->flags);
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/* TODO: relax CAP_SYS_ADMIN once backing files are visible to lsof */
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res = -EPERM;
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if (!fc->passthrough || !capable(CAP_SYS_ADMIN))
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goto out;
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res = -EINVAL;
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if (map->flags || map->padding)
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goto out;
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file = fget_raw(map->fd);
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res = -EBADF;
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if (!file)
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goto out;
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/* read/write/splice/mmap passthrough only relevant for regular files */
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res = d_is_dir(file->f_path.dentry) ? -EISDIR : -EINVAL;
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if (!d_is_reg(file->f_path.dentry))
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goto out_fput;
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backing_sb = file_inode(file)->i_sb;
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res = -ELOOP;
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if (backing_sb->s_stack_depth >= fc->max_stack_depth)
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goto out_fput;
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fb = kmalloc(sizeof(struct fuse_backing), GFP_KERNEL);
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res = -ENOMEM;
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if (!fb)
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goto out_fput;
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fb->file = file;
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fb->cred = prepare_creds();
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refcount_set(&fb->count, 1);
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res = fuse_backing_id_alloc(fc, fb);
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if (res < 0) {
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fuse_backing_free(fb);
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fb = NULL;
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}
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out:
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pr_debug("%s: fb=0x%p, ret=%i\n", __func__, fb, res);
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return res;
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out_fput:
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fput(file);
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goto out;
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}
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int fuse_backing_close(struct fuse_conn *fc, int backing_id)
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{
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struct fuse_backing *fb = NULL;
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int err;
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pr_debug("%s: backing_id=%d\n", __func__, backing_id);
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/* TODO: relax CAP_SYS_ADMIN once backing files are visible to lsof */
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err = -EPERM;
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if (!fc->passthrough || !capable(CAP_SYS_ADMIN))
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goto out;
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err = -EINVAL;
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if (backing_id <= 0)
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goto out;
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err = -ENOENT;
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fb = fuse_backing_id_remove(fc, backing_id);
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if (!fb)
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goto out;
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fuse_backing_put(fb);
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err = 0;
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out:
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pr_debug("%s: fb=0x%p, err=%i\n", __func__, fb, err);
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return err;
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}
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/*
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* Setup passthrough to a backing file.
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*
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@ -318,12 +161,8 @@ struct fuse_backing *fuse_passthrough_open(struct file *file, int backing_id)
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if (backing_id <= 0)
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goto out;
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rcu_read_lock();
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fb = idr_find(&fc->backing_files_map, backing_id);
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fb = fuse_backing_get(fb);
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rcu_read_unlock();
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err = -ENOENT;
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fb = fuse_backing_lookup(fc, backing_id);
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if (!fb)
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goto out;
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