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, 19 insertions, 11 deletions

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 73e3d47e7b2d..55da9a91f51a 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -257,7 +257,8 @@ out:
  * Returns zero on success; non-zero on error condition
  */
 static int
-ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
+ecryptfs_create(struct user_namespace *mnt_userns,
+		struct inode *directory_inode, struct dentry *ecryptfs_dentry,
 		umode_t mode, bool excl)
 {
 	struct inode *ecryptfs_inode;
@@ -463,7 +464,8 @@ static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
 	return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
 }
 
-static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
+static int ecryptfs_symlink(struct user_namespace *mnt_userns,
+			    struct inode *dir, struct dentry *dentry,
 			    const char *symname)
 {
 	int rc;
@@ -502,7 +504,8 @@ out_lock:
 	return rc;
 }
 
-static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int ecryptfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+			  struct dentry *dentry, umode_t mode)
 {
 	int rc;
 	struct dentry *lower_dentry;
@@ -559,7 +562,8 @@ static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 }
 
 static int
-ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
+ecryptfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+	       struct dentry *dentry, umode_t mode, dev_t dev)
 {
 	int rc;
 	struct dentry *lower_dentry;
@@ -584,9 +588,9 @@ out:
 }
 
 static int
-ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-		struct inode *new_dir, struct dentry *new_dentry,
-		unsigned int flags)
+ecryptfs_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)
 {
 	int rc;
 	struct dentry *lower_old_dentry;
@@ -874,7 +878,8 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
 }
 
 static int
-ecryptfs_permission(struct inode *inode, int mask)
+ecryptfs_permission(struct user_namespace *mnt_userns, struct inode *inode,
+		    int mask)
 {
 	return inode_permission(&init_user_ns,
 				ecryptfs_inode_to_lower(inode), mask);
@@ -892,7 +897,8 @@ ecryptfs_permission(struct inode *inode, int mask)
  * All other metadata changes will be passed right to the lower filesystem,
  * and we will just update our inode to look like the lower.
  */
-static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
+static int ecryptfs_setattr(struct user_namespace *mnt_userns,
+			    struct dentry *dentry, struct iattr *ia)
 {
 	int rc = 0;
 	struct dentry *lower_dentry;
@@ -979,7 +985,8 @@ out:
 	return rc;
 }
 
-static int ecryptfs_getattr_link(const struct path *path, struct kstat *stat,
+static int ecryptfs_getattr_link(struct user_namespace *mnt_userns,
+				 const struct path *path, struct kstat *stat,
 				 u32 request_mask, unsigned int flags)
 {
 	struct dentry *dentry = path->dentry;
@@ -1004,7 +1011,8 @@ static int ecryptfs_getattr_link(const struct path *path, struct kstat *stat,
 	return rc;
 }
 
-static int ecryptfs_getattr(const struct path *path, struct kstat *stat,
+static int ecryptfs_getattr(struct user_namespace *mnt_userns,
+			    const struct path *path, struct kstat *stat,
 			    u32 request_mask, unsigned int flags)
 {
 	struct dentry *dentry = path->dentry;