fs: make helpers idmap mount aware

Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

1 files changed, 18 insertions, 16 deletions

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 7bd659ad959e..714fcca9af99 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -28,18 +28,19 @@ static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name, int
 				  loff_t fpos, u64 ino, unsigned dtype);
 static int afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,
 			      loff_t fpos, u64 ino, unsigned dtype);
-static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
-		      bool excl);
-static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
+static int afs_create(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode, bool excl);
+static int afs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		     struct dentry *dentry, umode_t mode);
 static int afs_rmdir(struct inode *dir, struct dentry *dentry);
 static int afs_unlink(struct inode *dir, struct dentry *dentry);
 static int afs_link(struct dentry *from, struct inode *dir,
 		    struct dentry *dentry);
-static int afs_symlink(struct inode *dir, struct dentry *dentry,
-		       const char *content);
-static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
-		      struct inode *new_dir, struct dentry *new_dentry,
-		      unsigned int flags);
+static int afs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, const char *content);
+static int afs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+		      struct dentry *old_dentry, struct inode *new_dir,
+		      struct dentry *new_dentry, unsigned int flags);
 static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags);
 static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
 				   unsigned int length);
@@ -1325,7 +1326,8 @@ static const struct afs_operation_ops afs_mkdir_operation = {
 /*
  * create a directory on an AFS filesystem
  */
-static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int afs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		     struct dentry *dentry, umode_t mode)
 {
 	struct afs_operation *op;
 	struct afs_vnode *dvnode = AFS_FS_I(dir);
@@ -1619,8 +1621,8 @@ static const struct afs_operation_ops afs_create_operation = {
 /*
  * create a regular file on an AFS filesystem
  */
-static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
-		      bool excl)
+static int afs_create(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode, bool excl)
 {
 	struct afs_operation *op;
 	struct afs_vnode *dvnode = AFS_FS_I(dir);
@@ -1741,8 +1743,8 @@ static const struct afs_operation_ops afs_symlink_operation = {
 /*
  * create a symlink in an AFS filesystem
  */
-static int afs_symlink(struct inode *dir, struct dentry *dentry,
-		       const char *content)
+static int afs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, const char *content)
 {
 	struct afs_operation *op;
 	struct afs_vnode *dvnode = AFS_FS_I(dir);
@@ -1876,9 +1878,9 @@ static const struct afs_operation_ops afs_rename_operation = {
 /*
  * rename a file in an AFS filesystem and/or move it between directories
  */
-static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
-		      struct inode *new_dir, struct dentry *new_dentry,
-		      unsigned int flags)
+static int afs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+		      struct dentry *old_dentry, struct inode *new_dir,
+		      struct dentry *new_dentry, unsigned int flags)
 {
 	struct afs_operation *op;
 	struct afs_vnode *orig_dvnode, *new_dvnode, *vnode;