[PATCH v2 5/9] fs/fuse: support idmapped ->setattr op

[Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>]

Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Seth Forshee <sforshee@xxxxxxxxxx>
Cc: Miklos Szeredi <miklos@xxxxxxxxxx>
Cc: Amir Goldstein <amir73il@xxxxxxxxx>
Cc: Bernd Schubert <bschubert@xxxxxxx>
Cc: <linux-fsdevel@xxxxxxxxxxxxxxx>
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
---
 fs/fuse/dir.c    | 32 +++++++++++++++++++++-----------
 fs/fuse/file.c   |  2 +-
 fs/fuse/fuse_i.h |  4 ++--
 3 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index cd3b91b60cae..c50f951596dd 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1771,17 +1771,27 @@ static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
 	return true;
 }
 
-static void iattr_to_fattr(struct fuse_conn *fc, struct iattr *iattr,
-			   struct fuse_setattr_in *arg, bool trust_local_cmtime)
+static void iattr_to_fattr(struct mnt_idmap *idmap, struct fuse_conn *fc,
+			   struct iattr *iattr, struct fuse_setattr_in *arg,
+			   bool trust_local_cmtime)
 {
 	unsigned ivalid = iattr->ia_valid;
 
 	if (ivalid & ATTR_MODE)
 		arg->valid |= FATTR_MODE,   arg->mode = iattr->ia_mode;
-	if (ivalid & ATTR_UID)
-		arg->valid |= FATTR_UID,    arg->uid = from_kuid(fc->user_ns, iattr->ia_uid);
-	if (ivalid & ATTR_GID)
-		arg->valid |= FATTR_GID,    arg->gid = from_kgid(fc->user_ns, iattr->ia_gid);
+
+	if (ivalid & ATTR_UID) {
+		kuid_t fsuid = from_vfsuid(idmap, fc->user_ns, iattr->ia_vfsuid);
+		arg->valid |= FATTR_UID;
+		arg->uid = from_kuid(fc->user_ns, fsuid);
+	}
+
+	if (ivalid & ATTR_GID) {
+		kgid_t fsgid = from_vfsgid(idmap, fc->user_ns, iattr->ia_vfsgid);
+		arg->valid |= FATTR_GID;
+		arg->gid = from_kgid(fc->user_ns, fsgid);
+	}
+
 	if (ivalid & ATTR_SIZE)
 		arg->valid |= FATTR_SIZE,   arg->size = iattr->ia_size;
 	if (ivalid & ATTR_ATIME) {
@@ -1901,8 +1911,8 @@ int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
  * vmtruncate() doesn't allow for this case, so do the rlimit checking
  * and the actual truncation by hand.
  */
-int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
-		    struct file *file)
+int fuse_do_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+		    struct iattr *attr, struct file *file)
 {
 	struct inode *inode = d_inode(dentry);
 	struct fuse_mount *fm = get_fuse_mount(inode);
@@ -1922,7 +1932,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
 	if (!fc->default_permissions)
 		attr->ia_valid |= ATTR_FORCE;
 
-	err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
+	err = setattr_prepare(idmap, dentry, attr);
 	if (err)
 		return err;
 
@@ -1981,7 +1991,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
 
 	memset(&inarg, 0, sizeof(inarg));
 	memset(&outarg, 0, sizeof(outarg));
-	iattr_to_fattr(fc, attr, &inarg, trust_local_cmtime);
+	iattr_to_fattr(idmap, fc, attr, &inarg, trust_local_cmtime);
 	if (file) {
 		struct fuse_file *ff = file->private_data;
 		inarg.valid |= FATTR_FH;
@@ -2116,7 +2126,7 @@ static int fuse_setattr(struct mnt_idmap *idmap, struct dentry *entry,
 	if (!attr->ia_valid)
 		return 0;
 
-	ret = fuse_do_setattr(entry, attr, file);
+	ret = fuse_do_setattr(idmap, entry, attr, file);
 	if (!ret) {
 		/*
 		 * If filesystem supports acls it may have updated acl xattrs in
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index f39456c65ed7..562bdf8d5976 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2966,7 +2966,7 @@ static void fuse_do_truncate(struct file *file)
 	attr.ia_file = file;
 	attr.ia_valid |= ATTR_FILE;
 
-	fuse_do_setattr(file_dentry(file), &attr, file);
+	fuse_do_setattr(file_mnt_idmap(file), file_dentry(file), &attr, file);
 }
 
 static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index d06934e70cc5..883151a44d72 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1333,8 +1333,8 @@ bool fuse_write_update_attr(struct inode *inode, loff_t pos, ssize_t written);
 int fuse_flush_times(struct inode *inode, struct fuse_file *ff);
 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
 
-int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
-		    struct file *file);
+int fuse_do_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+		    struct iattr *attr, struct file *file);
 
 void fuse_set_initialized(struct fuse_conn *fc);
 
-- 
2.34.1