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>

3 files changed, 18 insertions, 14 deletions

diff --git a/fs/udf/file.c b/fs/udf/file.c
index 7c7d161315c2..2846dcd92197 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -253,7 +253,8 @@ const struct file_operations udf_file_operations = {
 	.llseek			= generic_file_llseek,
 };
 
-static int udf_setattr(struct dentry *dentry, struct iattr *attr)
+static int udf_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		       struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	struct super_block *sb = inode->i_sb;
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index e169d8fe35b5..f146b3089f3d 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -604,8 +604,8 @@ static int udf_add_nondir(struct dentry *dentry, struct inode *inode)
 	return 0;
 }
 
-static int udf_create(struct inode *dir, struct dentry *dentry, umode_t mode,
-		      bool excl)
+static int udf_create(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode, bool excl)
 {
 	struct inode *inode = udf_new_inode(dir, mode);
 
@@ -623,7 +623,8 @@ static int udf_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 	return udf_add_nondir(dentry, inode);
 }
 
-static int udf_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int udf_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, umode_t mode)
 {
 	struct inode *inode = udf_new_inode(dir, mode);
 
@@ -642,8 +643,8 @@ static int udf_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode)
 	return 0;
 }
 
-static int udf_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
-		     dev_t rdev)
+static int udf_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+		     struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	struct inode *inode;
 
@@ -658,7 +659,8 @@ static int udf_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
 	return udf_add_nondir(dentry, inode);
 }
 
-static int udf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int udf_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		     struct dentry *dentry, umode_t mode)
 {
 	struct inode *inode;
 	struct udf_fileident_bh fibh;
@@ -877,8 +879,8 @@ out:
 	return retval;
 }
 
-static int udf_symlink(struct inode *dir, struct dentry *dentry,
-		       const char *symname)
+static int udf_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, const char *symname)
 {
 	struct inode *inode = udf_new_inode(dir, S_IFLNK | 0777);
 	struct pathComponent *pc;
@@ -1065,9 +1067,9 @@ static int udf_link(struct dentry *old_dentry, struct inode *dir,
 /* Anybody can rename anything with this: the permission checks are left to the
  * higher-level routines.
  */
-static int udf_rename(struct inode *old_dir, struct dentry *old_dentry,
-		      struct inode *new_dir, struct dentry *new_dentry,
-		      unsigned int flags)
+static int udf_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 inode *old_inode = d_inode(old_dentry);
 	struct inode *new_inode = d_inode(new_dentry);
diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c
index 54a44d1f023c..9b223421a3c5 100644
--- a/fs/udf/symlink.c
+++ b/fs/udf/symlink.c
@@ -152,8 +152,9 @@ out_unmap:
 	return err;
 }
 
-static int udf_symlink_getattr(const struct path *path, struct kstat *stat,
-				u32 request_mask, unsigned int flags)
+static int udf_symlink_getattr(struct user_namespace *mnt_userns,
+			       const struct path *path, struct kstat *stat,
+			       u32 request_mask, unsigned int flags)
 {
 	struct dentry *dentry = path->dentry;
 	struct inode *inode = d_backing_inode(dentry);