This adds a backing implementation for mapping, but no bpf counterpart
yet.
Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx>
Signed-off-by: Paul Lawrence <paullawrence@xxxxxxxxxx>
---
fs/fuse/backing.c | 37 +++++++++++++++++++++++++++++++++++++
fs/fuse/file.c | 6 ++++++
fs/fuse/fuse_i.h | 3 +++
3 files changed, 46 insertions(+)
diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c
index 51088701e7ad..fa8805e24061 100644
--- a/fs/fuse/backing.c
+++ b/fs/fuse/backing.c
@@ -77,6 +77,43 @@ int parse_fuse_entry_bpf(struct fuse_entry_bpf *feb)
return err;
}
+ssize_t fuse_backing_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ int ret;
+ struct fuse_file *ff = file->private_data;
+ struct inode *fuse_inode = file_inode(file);
+ struct file *backing_file = ff->backing_file;
+ struct inode *backing_inode = file_inode(backing_file);
+
+ if (!backing_file->f_op->mmap)
+ return -ENODEV;
+
+ if (WARN_ON(file != vma->vm_file))
+ return -EIO;
+
+ vma->vm_file = get_file(backing_file);
+
+ ret = call_mmap(vma->vm_file, vma);
+
+ if (ret)
+ fput(backing_file);
+ else
+ fput(file);
+
+ if (file->f_flags & O_NOATIME)
+ return ret;
+
+ if ((!timespec64_equal(&fuse_inode->i_mtime, &backing_inode->i_mtime) ||
+ !timespec64_equal(&fuse_inode->i_ctime,
+ &backing_inode->i_ctime))) {
+ fuse_inode->i_mtime = backing_inode->i_mtime;
+ fuse_inode->i_ctime = backing_inode->i_ctime;
+ }
+ touch_atime(&file->f_path);
+
+ return ret;
+}
+
/*******************************************************************************
* Directory operations after here *
******************************************************************************/
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 4fa2ebc068f0..138890eae07c 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2452,6 +2452,12 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
if (FUSE_IS_DAX(file_inode(file)))
return fuse_dax_mmap(file, vma);
+#ifdef CONFIG_FUSE_BPF
+ /* TODO - this is simply passthrough, not a proper BPF filter */
+ if (ff->backing_file)
+ return fuse_backing_mmap(file, vma);
+#endif
+
if (ff->open_flags & FOPEN_DIRECT_IO) {
/* Can't provide the coherency needed for MAP_SHARED */
if (vma->vm_flags & VM_MAYSHARE)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 30ddc298fb27..a9653f71c145 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1404,8 +1404,11 @@ struct fuse_entry_bpf {
struct bpf_prog *bpf;
};
+
int parse_fuse_entry_bpf(struct fuse_entry_bpf *feb);
+ssize_t fuse_backing_mmap(struct file *file, struct vm_area_struct *vma);
+
struct fuse_lookup_io {
struct fuse_entry_out feo;
struct fuse_entry_bpf feb;
--
2.37.3.998.g577e59143f-goog
