fs: port ->getattr() to pass mnt_idmap

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>

3 files changed, 8 insertions, 8 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 056704d4ac9c..b5e325434c5a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2979,11 +2979,11 @@ extern int  ext4_write_inode(struct inode *, struct writeback_control *);
 extern int  ext4_setattr(struct mnt_idmap *, struct dentry *,
 			 struct iattr *);
 extern u32  ext4_dio_alignment(struct inode *inode);
-extern int  ext4_getattr(struct user_namespace *, const struct path *,
+extern int  ext4_getattr(struct mnt_idmap *, const struct path *,
 			 struct kstat *, u32, unsigned int);
 extern void ext4_evict_inode(struct inode *);
 extern void ext4_clear_inode(struct inode *);
-extern int  ext4_file_getattr(struct user_namespace *, const struct path *,
+extern int  ext4_file_getattr(struct mnt_idmap *, const struct path *,
 			      struct kstat *, u32, unsigned int);
 extern int  ext4_sync_inode(handle_t *, struct inode *);
 extern void ext4_dirty_inode(struct inode *, int);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 18fed4f5108d..d60eab65319d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5669,7 +5669,7 @@ u32 ext4_dio_alignment(struct inode *inode)
 	return 1; /* use the iomap defaults */
 }
 
-int ext4_getattr(struct user_namespace *mnt_userns, const struct path *path,
+int ext4_getattr(struct mnt_idmap *idmap, const struct path *path,
 		 struct kstat *stat, u32 request_mask, unsigned int query_flags)
 {
 	struct inode *inode = d_inode(path->dentry);
@@ -5726,18 +5726,18 @@ int ext4_getattr(struct user_namespace *mnt_userns, const struct path *path,
 				  STATX_ATTR_NODUMP |
 				  STATX_ATTR_VERITY);
 
-	generic_fillattr(mnt_userns, inode, stat);
+	generic_fillattr(idmap, inode, stat);
 	return 0;
 }
 
-int ext4_file_getattr(struct user_namespace *mnt_userns,
+int ext4_file_getattr(struct mnt_idmap *idmap,
 		      const struct path *path, struct kstat *stat,
 		      u32 request_mask, unsigned int query_flags)
 {
 	struct inode *inode = d_inode(path->dentry);
 	u64 delalloc_blocks;
 
-	ext4_getattr(mnt_userns, path, stat, request_mask, query_flags);
+	ext4_getattr(idmap, path, stat, request_mask, query_flags);
 
 	/*
 	 * If there is inline data in the inode, the inode will normally not
diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 3d3ed3c38f56..75bf1f88843c 100644
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -55,12 +55,12 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
 	return paddr;
 }
 
-static int ext4_encrypted_symlink_getattr(struct user_namespace *mnt_userns,
+static int ext4_encrypted_symlink_getattr(struct mnt_idmap *idmap,
 					  const struct path *path,
 					  struct kstat *stat, u32 request_mask,
 					  unsigned int query_flags)
 {
-	ext4_getattr(mnt_userns, path, stat, request_mask, query_flags);
+	ext4_getattr(idmap, path, stat, request_mask, query_flags);
 
 	return fscrypt_symlink_getattr(path, stat);
 }