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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
commitf4cdf7ca9a1fdcca413157df19753f388a5a224e (patch)
tree60a31895b2446cd7fa27514e8c2843534a0de0da /fs/fuse/backing.c
downloadlinux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz
linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab: - v4l2-core: added ISP statistics support and per-block validation - v4l2-core: Allow unknown HDR10 white point and luminance - New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor - New codec: Milos: VPU v2.0 codec support - isp driver: gained support for Dreamchip RPPX1 ISP framework - vsp1 driver: gained support for RZ/T2H and RZ/N2H - Novalake driver: gained CVS support for new NVL hardware - dvb-core: fix feed leak on failed DMX_ADD_PID - several driver fixes, cleanups and minor improvements * tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits) media: ipu-bridge: check all DMI entries when overriding sensor rotation media: v4l2-async: avoid deleting unlinked ASC entry on link error media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement media: intel/ipu6: fix async notifier cleanup leak on parse error media: staging/ipu7: fix async notifier UAF on probe error path media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem() media: rcar-isp: Fix VSPX reference leaks media: rcar-isp: Release ISPCORE resources media: i2c: imx415: Release runtime PM reference on VBLANK error media: i2c: imx415: Return test pattern write errors media: renesas: vsp1: Declare index variables in for loop statement media: renesas: vsp1: Make reset control optional to support platforms without a reset line media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs media: nxp: imx8-isi: Add additional 32-bit RGB format support media: nxp: imx8-isi: Add 16-bit raw Bayer format support media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks media: nxp: imx8-isi: Correct color map between V4L2 and ISI ...
Diffstat (limited to 'fs/fuse/backing.c')
-rw-r--r--fs/fuse/backing.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c
new file mode 100644
index 000000000..472b6afa7
--- /dev/null
+++ b/fs/fuse/backing.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * FUSE passthrough to backing file.
+ *
+ * Copyright (c) 2023 CTERA Networks.
+ */
+
+#include "dev.h"
+#include "fuse_i.h"
+
+#include <linux/file.h>
+
+struct fuse_backing *fuse_backing_get(struct fuse_backing *fb)
+{
+ if (fb && refcount_inc_not_zero(&fb->count))
+ return fb;
+ return NULL;
+}
+
+static void fuse_backing_free(struct fuse_backing *fb)
+{
+ pr_debug("%s: fb=0x%p\n", __func__, fb);
+
+ if (fb->file)
+ fput(fb->file);
+ put_cred(fb->cred);
+ kfree_rcu(fb, rcu);
+}
+
+void fuse_backing_put(struct fuse_backing *fb)
+{
+ if (fb && refcount_dec_and_test(&fb->count))
+ fuse_backing_free(fb);
+}
+
+void fuse_backing_files_init(struct fuse_conn *fc)
+{
+ idr_init(&fc->backing_files_map);
+}
+
+static int fuse_backing_id_alloc(struct fuse_conn *fc, struct fuse_backing *fb)
+{
+ int id;
+
+ idr_preload(GFP_KERNEL);
+ spin_lock(&fc->lock);
+ /* FIXME: xarray might be space inefficient */
+ id = idr_alloc_cyclic(&fc->backing_files_map, fb, 1, 0, GFP_ATOMIC);
+ spin_unlock(&fc->lock);
+ idr_preload_end();
+
+ WARN_ON_ONCE(id == 0);
+ return id;
+}
+
+static struct fuse_backing *fuse_backing_id_remove(struct fuse_conn *fc,
+ int id)
+{
+ struct fuse_backing *fb;
+
+ spin_lock(&fc->lock);
+ fb = idr_remove(&fc->backing_files_map, id);
+ spin_unlock(&fc->lock);
+
+ return fb;
+}
+
+static int fuse_backing_id_free(int id, void *p, void *data)
+{
+ struct fuse_backing *fb = p;
+
+ WARN_ON_ONCE(refcount_read(&fb->count) != 1);
+ fuse_backing_free(fb);
+ return 0;
+}
+
+void fuse_backing_files_free(struct fuse_conn *fc)
+{
+ idr_for_each(&fc->backing_files_map, fuse_backing_id_free, NULL);
+ idr_destroy(&fc->backing_files_map);
+}
+
+int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map)
+{
+ struct file *file;
+ struct super_block *backing_sb;
+ struct fuse_backing *fb = NULL;
+ int res;
+
+ pr_debug("%s: fd=%d flags=0x%x\n", __func__, map->fd, map->flags);
+
+ /* TODO: relax CAP_SYS_ADMIN once backing files are visible to lsof */
+ res = -EPERM;
+ if (!fc->passthrough || !capable(CAP_SYS_ADMIN))
+ goto out;
+
+ res = -EINVAL;
+ if (map->flags || map->padding)
+ goto out;
+
+ file = fget_raw(map->fd);
+ res = -EBADF;
+ if (!file)
+ goto out;
+
+ /* read/write/splice/mmap passthrough only relevant for regular files */
+ res = d_is_dir(file->f_path.dentry) ? -EISDIR : -EINVAL;
+ if (!d_is_reg(file->f_path.dentry))
+ goto out_fput;
+
+ backing_sb = file_inode(file)->i_sb;
+ res = -ELOOP;
+ if (backing_sb->s_stack_depth >= fc->max_stack_depth)
+ goto out_fput;
+
+ fb = kmalloc_obj(struct fuse_backing);
+ res = -ENOMEM;
+ if (!fb)
+ goto out_fput;
+
+ fb->file = file;
+ fb->cred = get_current_cred();
+ refcount_set(&fb->count, 1);
+
+ res = fuse_backing_id_alloc(fc, fb);
+ if (res < 0) {
+ fuse_backing_free(fb);
+ fb = NULL;
+ }
+
+out:
+ pr_debug("%s: fb=0x%p, ret=%i\n", __func__, fb, res);
+
+ return res;
+
+out_fput:
+ fput(file);
+ goto out;
+}
+
+int fuse_backing_close(struct fuse_conn *fc, int backing_id)
+{
+ struct fuse_backing *fb = NULL;
+ int err;
+
+ pr_debug("%s: backing_id=%d\n", __func__, backing_id);
+
+ /* TODO: relax CAP_SYS_ADMIN once backing files are visible to lsof */
+ err = -EPERM;
+ if (!fc->passthrough || !capable(CAP_SYS_ADMIN))
+ goto out;
+
+ err = -EINVAL;
+ if (backing_id <= 0)
+ goto out;
+
+ err = -ENOENT;
+ fb = fuse_backing_id_remove(fc, backing_id);
+ if (!fb)
+ goto out;
+
+ fuse_backing_put(fb);
+ err = 0;
+out:
+ pr_debug("%s: fb=0x%p, err=%i\n", __func__, fb, err);
+
+ return err;
+}
+
+struct fuse_backing *fuse_backing_lookup(struct fuse_conn *fc, int backing_id)
+{
+ struct fuse_backing *fb;
+
+ rcu_read_lock();
+ fb = idr_find(&fc->backing_files_map, backing_id);
+ fb = fuse_backing_get(fb);
+ rcu_read_unlock();
+
+ return fb;
+}