[RFC PATCH v4 16/36] fuse-bpf: Add Rename support

Daniel Rosenberg
2024-03-29T01:54:35Z

This adds backing support for FUSE_RENAME and FUSE_RENAME2

Signed-off-by: Daniel Rosenberg <drosen@google.com>
Signed-off-by: Paul Lawrence <paullawrence@google.com>
---
fs/fuse/backing.c | 250 ++++++++++++++++++++++++++++++++++++++++++++++
fs/fuse/dir.c | 7 ++
fs/fuse/fuse_i.h | 18 ++++
3 files changed, 275 insertions(+)

diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c
index c2c5cb3d3d6e..79f14634ae6a 100644
--- a/fs/fuse/backing.c
+++ b/fs/fuse/backing.c
@@ -1735,6 +1735,256 @@ int fuse_bpf_rmdir(int *out, struct inode *dir, struct dentry *entry)
dir, entry);
}

+static int fuse_rename_backing_common(struct inode *olddir,
+ struct dentry *oldent,
+ struct inode *newdir,
+ struct dentry *newent, unsigned int flags)
+{
+ int err = 0;
+ struct path old_backing_path;
+ struct path new_backing_path;
+ struct dentry *old_backing_dir_dentry;
+ struct dentry *old_backing_dentry;
+ struct dentry *new_backing_dir_dentry;
+ struct dentry *new_backing_dentry;
+ struct dentry *trap = NULL;
+ struct inode *target_inode;
+ struct renamedata rd;
+
+ //TODO Actually deal with changing anything that isn't a flag
+ get_fuse_backing_path(oldent, &old_backing_path);
+ if (!old_backing_path.dentry)
+ return -EBADF;
+ get_fuse_backing_path(newent, &new_backing_path);
+ if (!new_backing_path.dentry) {
+ /*
+ * TODO A file being moved from a backing path to another
+ * backing path which is not yet instrumented with FUSE-BPF.
+ * This may be slow and should be substituted with something
+ * more clever.
+ */
+ err = -EXDEV;
+ goto put_old_path;
+ }
+ if (new_backing_path.mnt != old_backing_path.mnt) {
+ err = -EXDEV;
+ goto put_new_path;
+ }
+ old_backing_dentry = old_backing_path.dentry;
+ new_backing_dentry = new_backing_path.dentry;
+ old_backing_dir_dentry = dget_parent(old_backing_dentry);
+ new_backing_dir_dentry = dget_parent(new_backing_dentry);
+ target_inode = d_inode(newent);
+
+ trap = lock_rename(old_backing_dir_dentry, new_backing_dir_dentry);
+ if (trap == old_backing_dentry) {
+ err = -EINVAL;
+ goto put_parents;
+ }
+ if (trap == new_backing_dentry) {
+ err = -ENOTEMPTY;
+ goto put_parents;
+ }
+
+ rd = (struct renamedata) {
+ .old_mnt_idmap = &nop_mnt_idmap,
+ .old_dir = d_inode(old_backing_dir_dentry),
+ .old_dentry = old_backing_dentry,
+ .new_mnt_idmap = &nop_mnt_idmap,
+ .new_dir = d_inode(new_backing_dir_dentry),
+ .new_dentry = new_backing_dentry,
+ .flags = flags,
+ };
+ err = vfs_rename(&rd);
+ if (err)
+ goto unlock;
+ if (target_inode)
+ fsstack_copy_attr_all(target_inode,
+ get_fuse_inode(target_inode)->backing_inode);
+ fsstack_copy_attr_all(d_inode(oldent), d_inode(old_backing_dentry));
+unlock:
+ unlock_rename(old_backing_dir_dentry, new_backing_dir_dentry);
+put_parents:
+ dput(new_backing_dir_dentry);
+ dput(old_backing_dir_dentry);
+put_new_path:
+ path_put(&new_backing_path);
+put_old_path:
+ path_put(&old_backing_path);
+ return err;
+}
+
+struct fuse_rename2_args {
+ struct fuse_rename2_in in;
+ struct fuse_buffer old_name;
+ struct fuse_buffer new_name;
+};
+
+static int fuse_rename2_initialize_in(struct bpf_fuse_args *fa, struct fuse_rename2_args *args,
+ struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent,
+ unsigned int flags)
+{
+ *args = (struct fuse_rename2_args) {
+ .in = (struct fuse_rename2_in) {
+ .newdir = get_node_id(newdir),
+ .flags = flags,
+ },
+ .old_name = (struct fuse_buffer) {
+ .data = (void *) oldent->d_name.name,
+ .size = oldent->d_name.len + 1,
+ .flags = BPF_FUSE_IMMUTABLE,
+ },
+ .new_name = (struct fuse_buffer) {
+ .data = (void *) newent->d_name.name,
+ .size = newent->d_name.len + 1,
+ .flags = BPF_FUSE_IMMUTABLE,
+ },
+
+ };
+ *fa = (struct bpf_fuse_args) {
+ .info = (struct bpf_fuse_meta_info) {
+ .nodeid = get_node_id(olddir),
+ .opcode = FUSE_RENAME2,
+ },
+ .in_numargs = 3,
+ .in_args[0] = (struct bpf_fuse_arg) {
+ .size = sizeof(args->in),
+ .value = &args->in,
+ },
+ .in_args[1] = (struct bpf_fuse_arg) {
+ .is_buffer = true,
+ .buffer = &args->old_name,
+ },
+ .in_args[2] = (struct bpf_fuse_arg) {
+ .is_buffer = true,
+ .buffer = &args->new_name,
+ },
+ };
+
+ return 0;
+}
+
+static int fuse_rename2_initialize_out(struct bpf_fuse_args *fa, struct fuse_rename2_args *args,
+ struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent,
+ unsigned int flags)
+{
+ return 0;
+}
+
+static int fuse_rename2_backing(struct bpf_fuse_args *fa, int *out,
+ struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent,
+ unsigned int flags)
+{
+ const struct fuse_rename2_args *fri = fa->in_args[0].value;
+
+ /* TODO: deal with changing dirs/ents */
+ *out = fuse_rename_backing_common(olddir, oldent, newdir, newent,
+ fri->in.flags);
+ return *out;
+}
+
+static int fuse_rename2_finalize(struct bpf_fuse_args *fa, int *out,
+ struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent,
+ unsigned int flags)
+{
+ return 0;
+}
+
+int fuse_bpf_rename2(int *out, struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent,
+ unsigned int flags)
+{
+ return bpf_fuse_backing(olddir, struct fuse_rename2_args, out,
+ fuse_rename2_initialize_in, fuse_rename2_initialize_out,
+ fuse_rename2_backing, fuse_rename2_finalize,
+ olddir, oldent, newdir, newent, flags);
+}
+
+struct fuse_rename_args {
+ struct fuse_rename_in in;
+ struct fuse_buffer old_name;
+ struct fuse_buffer new_name;
+};
+
+static int fuse_rename_initialize_in(struct bpf_fuse_args *fa, struct fuse_rename_args *args,
+ struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent)
+{
+ *args = (struct fuse_rename_args) {
+ .in = (struct fuse_rename_in) {
+ .newdir = get_node_id(newdir),
+ },
+ .old_name = (struct fuse_buffer) {
+ .data = (void *) oldent->d_name.name,
+ .size = oldent->d_name.len + 1,
+ .flags = BPF_FUSE_IMMUTABLE,
+ },
+ .new_name = (struct fuse_buffer) {
+ .data = (void *) newent->d_name.name,
+ .size = newent->d_name.len + 1,
+ .flags = BPF_FUSE_IMMUTABLE,
+ },
+
+ };
+ *fa = (struct bpf_fuse_args) {
+ .info = (struct bpf_fuse_meta_info) {
+ .nodeid = get_node_id(olddir),
+ .opcode = FUSE_RENAME,
+ },
+ .in_numargs = 3,
+ .in_args[0] = (struct bpf_fuse_arg) {
+ .size = sizeof(args->in),
+ .value = &args->in,
+ },
+ .in_args[1] = (struct bpf_fuse_arg) {
+ .is_buffer = true,
+ .buffer = &args->old_name,
+ },
+ .in_args[2] = (struct bpf_fuse_arg) {
+ .is_buffer = true,
+ .buffer = &args->new_name,
+ },
+ };
+
+ return 0;
+}
+
+static int fuse_rename_initialize_out(struct bpf_fuse_args *fa, struct fuse_rename_args *args,
+ struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent)
+{
+ return 0;
+}
+
+static int fuse_rename_backing(struct bpf_fuse_args *fa, int *out,
+ struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent)
+{
+ /* TODO: deal with changing dirs/ents */
+ *out = fuse_rename_backing_common(olddir, oldent, newdir, newent, 0);
+ return *out;
+}
+
+static int fuse_rename_finalize(struct bpf_fuse_args *fa, int *out,
+ struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent)
+{
+ return 0;
+}
+
+int fuse_bpf_rename(int *out, struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent)
+{
+ return bpf_fuse_backing(olddir, struct fuse_rename_args, out,
+ fuse_rename_initialize_in, fuse_rename_initialize_out,
+ fuse_rename_backing, fuse_rename_finalize,
+ olddir, oldent, newdir, newent);
+}
+
static int fuse_unlink_initialize_in(struct bpf_fuse_args *fa, struct fuse_buffer *name,
struct inode *dir, struct dentry *entry)
{
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 7b661fcd5470..0426243d9345 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1204,6 +1204,10 @@ static int fuse_rename2(struct mnt_idmap *idmap, struct inode *olddir,
return -EINVAL;

if (flags) {
+ if (fuse_bpf_rename2(&err, olddir, oldent, newdir, newent, flags))
+ return err;
+
+ /* TODO: how should this go with bpfs involved? */
if (fc->no_rename2 || fc->minor < 23)
return -EINVAL;

@@ -1215,6 +1219,9 @@ static int fuse_rename2(struct mnt_idmap *idmap, struct inode *olddir,
err = -EINVAL;
}
} else {
+ if (fuse_bpf_rename(&err, olddir, oldent, newdir, newent))
+ return err;
+
err = fuse_rename_common(olddir, oldent, newdir, newent, 0,
FUSE_RENAME,
sizeof(struct fuse_rename_in));
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 256e217880c8..8bd78a52a6b5 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1444,6 +1444,11 @@ int fuse_bpf_create_open(int *out, struct inode *dir, struct dentry *entry,
int fuse_bpf_mknod(int *out, struct inode *dir, struct dentry *entry, umode_t mode, dev_t rdev);
int fuse_bpf_mkdir(int *out, struct inode *dir, struct dentry *entry, umode_t mode);
int fuse_bpf_rmdir(int *out, struct inode *dir, struct dentry *entry);
+int fuse_bpf_rename2(int *out, struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent,
+ unsigned int flags);
+int fuse_bpf_rename(int *out, struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent);
int fuse_bpf_unlink(int *out, struct inode *dir, struct dentry *entry);
int fuse_bpf_release(int *out, struct inode *inode, struct fuse_file *ff);
int fuse_bpf_releasedir(int *out, struct inode *inode, struct fuse_file *ff);
@@ -1486,6 +1491,19 @@ static inline int fuse_bpf_rmdir(int *out, struct inode *dir, struct dentry *ent
return 0;
}

+static inline int fuse_bpf_rename2(int *out, struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent,
+ unsigned int flags)
+{
+ return 0;
+}
+
+static inline int fuse_bpf_rename(int *out, struct inode *olddir, struct dentry *oldent,
+ struct inode *newdir, struct dentry *newent)
+{
+ return 0;
+}
+
static inline int fuse_bpf_unlink(int *out, struct inode *dir, struct dentry *entry)
{
return 0;
--
2.44.0.478.gd926399ef9-goog