[PATCH 1/3] fuse: make the root nodeid dynamic

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

Change this from a hardcoded constant to a dynamic field so that fuse
servers don't need to translate.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
 fs/fuse/fuse_i.h  |    7 +++++--
 fs/fuse/dir.c     |   10 ++++++----
 fs/fuse/inode.c   |   11 +++++++----
 fs/fuse/readdir.c |   10 +++++-----
 4 files changed, 23 insertions(+), 15 deletions(-)


diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index f96c69c755bd9b..fc0e352e2e8f9b 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -702,6 +702,9 @@ struct fuse_conn {
 
 	struct rcu_head rcu;
 
+	/* node id of the root directory */
+	u64 root_nodeid;
+
 	/** The user id for this mount */
 	kuid_t user_id;
 
@@ -1117,9 +1120,9 @@ static inline u64 get_node_id(struct inode *inode)
 	return get_fuse_inode(inode)->nodeid;
 }
 
-static inline int invalid_nodeid(u64 nodeid)
+static inline int invalid_nodeid(const struct fuse_conn *fc, u64 nodeid)
 {
-	return !nodeid || nodeid == FUSE_ROOT_ID;
+	return !nodeid || nodeid == fc->root_nodeid;
 }
 
 static inline u64 fuse_get_attr_version(struct fuse_conn *fc)
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 0492619e397f56..ff678f26e9cd79 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -580,7 +580,7 @@ int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name
 	err = -EIO;
 	if (fuse_invalid_attr(&outarg->attr))
 		goto out_put_forget;
-	if (outarg->nodeid == FUSE_ROOT_ID && outarg->generation != 0) {
+	if (outarg->nodeid == fm->fc->root_nodeid && outarg->generation != 0) {
 		pr_warn_once("root generation should be zero\n");
 		outarg->generation = 0;
 	}
@@ -630,7 +630,7 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
 		goto out_err;
 
 	err = -EIO;
-	if (inode && get_node_id(inode) == FUSE_ROOT_ID)
+	if (inode && get_node_id(inode) == fc->root_nodeid)
 		goto out_iput;
 
 	newent = d_splice_alias(inode, entry);
@@ -881,7 +881,8 @@ static int fuse_create_open(struct mnt_idmap *idmap, struct inode *dir,
 		goto out_free_ff;
 
 	err = -EIO;
-	if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid) ||
+	if (!S_ISREG(outentry.attr.mode) ||
+	    invalid_nodeid(fm->fc, outentry.nodeid) ||
 	    fuse_invalid_attr(&outentry.attr))
 		goto out_free_ff;
 
@@ -1028,7 +1029,8 @@ static struct dentry *create_new_entry(struct mnt_idmap *idmap, struct fuse_moun
 		goto out_put_forget_req;
 
 	err = -EIO;
-	if (invalid_nodeid(outarg.nodeid) || fuse_invalid_attr(&outarg.attr))
+	if (invalid_nodeid(fm->fc, outarg.nodeid) ||
+	    fuse_invalid_attr(&outarg.attr))
 		goto out_put_forget_req;
 
 	if ((outarg.attr.mode ^ mode) & S_IFMT)
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index f3afa63bfe7f61..2a679bce3b178c 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1030,6 +1030,7 @@ void fuse_conn_init(struct fuse_conn *fc, struct fuse_mount *fm,
 	fc->max_pages_limit = fuse_max_pages_limit;
 	fc->name_max = FUSE_NAME_LOW_MAX;
 	fc->timeout.req_timeout = 0;
+	fc->root_nodeid = FUSE_ROOT_ID;
 
 	if (IS_ENABLED(CONFIG_FUSE_BACKING))
 		fuse_backing_files_init(fc);
@@ -1087,12 +1088,14 @@ EXPORT_SYMBOL_GPL(fuse_conn_get);
 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned int mode)
 {
 	struct fuse_attr attr;
+	struct fuse_conn *fc = get_fuse_conn_super(sb);
+
 	memset(&attr, 0, sizeof(attr));
 
 	attr.mode = mode;
-	attr.ino = FUSE_ROOT_ID;
+	attr.ino = fc->root_nodeid;
 	attr.nlink = 1;
-	return fuse_iget(sb, FUSE_ROOT_ID, 0, &attr, 0, 0, 0);
+	return fuse_iget(sb, fc->root_nodeid, 0, &attr, 0, 0, 0);
 }
 
 struct fuse_inode_handle {
@@ -1136,7 +1139,7 @@ static struct dentry *fuse_get_dentry(struct super_block *sb,
 		goto out_iput;
 
 	entry = d_obtain_alias(inode);
-	if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID)
+	if (!IS_ERR(entry) && get_node_id(inode) != fc->root_nodeid)
 		fuse_invalidate_entry_cache(entry);
 
 	return entry;
@@ -1229,7 +1232,7 @@ static struct dentry *fuse_get_parent(struct dentry *child)
 	}
 
 	parent = d_obtain_alias(inode);
-	if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID)
+	if (!IS_ERR(parent) && get_node_id(inode) != fc->root_nodeid)
 		fuse_invalidate_entry_cache(parent);
 
 	return parent;
diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c
index c2aae2eef0868b..45dd932eb03a5e 100644
--- a/fs/fuse/readdir.c
+++ b/fs/fuse/readdir.c
@@ -185,12 +185,12 @@ static int fuse_direntplus_link(struct file *file,
 			return 0;
 	}
 
-	if (invalid_nodeid(o->nodeid))
-		return -EIO;
-	if (fuse_invalid_attr(&o->attr))
-		return -EIO;
-
 	fc = get_fuse_conn(dir);
+	if (invalid_nodeid(fc, o->nodeid))
+		return -EIO;
+	if (fuse_invalid_attr(&o->attr))
+		return -EIO;
+
 	epoch = atomic_read(&fc->epoch);
 
 	name.hash = full_name_hash(parent, name.name, name.len);