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Message-ID: <20230418014037.2412394-13-drosen@google.com>
Date: Mon, 17 Apr 2023 18:40:12 -0700
From: Daniel Rosenberg <drosen@...gle.com>
To: Miklos Szeredi <miklos@...redi.hu>, bpf@...r.kernel.org,
Alexei Starovoitov <ast@...nel.org>
Cc: Amir Goldstein <amir73il@...il.com>, linux-kernel@...r.kernel.org,
linux-fsdevel@...r.kernel.org, linux-unionfs@...r.kernel.org,
Daniel Borkmann <daniel@...earbox.net>,
John Fastabend <john.fastabend@...il.com>,
Andrii Nakryiko <andrii@...nel.org>,
Martin KaFai Lau <martin.lau@...ux.dev>,
Song Liu <song@...nel.org>, Yonghong Song <yhs@...com>,
KP Singh <kpsingh@...nel.org>,
Stanislav Fomichev <sdf@...gle.com>,
Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
Shuah Khan <shuah@...nel.org>,
Jonathan Corbet <corbet@....net>,
Joanne Koong <joannelkoong@...il.com>,
Mykola Lysenko <mykolal@...com>, kernel-team@...roid.com,
Daniel Rosenberg <drosen@...gle.com>,
Paul Lawrence <paullawrence@...gle.com>
Subject: [RFC PATCH v3 12/37] fuse-bpf: Partially add mapping support
This adds a backing implementation for mapping, but is not currently
hooked into the infrastructure that will call the bpf programs.
Signed-off-by: Daniel Rosenberg <drosen@...gle.com>
Signed-off-by: Paul Lawrence <paullawrence@...gle.com>
---
fs/fuse/backing.c | 37 +++++++++++++++++++++++++++++++++++++
fs/fuse/file.c | 6 ++++++
fs/fuse/fuse_i.h | 4 +++-
3 files changed, 46 insertions(+), 1 deletion(-)
diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c
index e42622584037..930aa370e376 100644
--- a/fs/fuse/backing.c
+++ b/fs/fuse/backing.c
@@ -207,6 +207,43 @@ static void fuse_stat_to_attr(struct fuse_conn *fc, struct inode *inode,
attr->blksize = 1 << blkbits;
}
+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 25fb49f0a9f7..865167a80d35 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2527,6 +2527,12 @@ 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 cb166168f9c2..5eb357f482dc 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1422,7 +1422,9 @@ static inline int fuse_bpf_access(int *out, struct inode *inode, int mask)
#endif // CONFIG_FUSE_BPF
-int fuse_handle_backing(struct fuse_bpf_entry *feb, struct path *backing_path);
+ssize_t fuse_backing_mmap(struct file *file, struct vm_area_struct *vma);
+
+int fuse_handle_backing(struct fuse_bpf_entry *fbe, struct path *backing_path);
int fuse_revalidate_backing(struct dentry *entry, unsigned int flags);
--
2.40.0.634.g4ca3ef3211-goog
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