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authorChristian Brauner <brauner@kernel.org>2022-09-22 18:17:00 +0300
committerChristian Brauner (Microsoft) <brauner@kernel.org>2022-10-20 11:13:27 +0300
commitcac2f8b8d8b50ef32b3e34f6dcbbf08937e4f616 (patch)
tree040a034efa1384a0f1f4034d4b36586638eaa921 /fs/overlayfs
parent138060ba92b3b0d77c8e6818d0f33398b23ea42e (diff)
downloadlinux-cac2f8b8d8b50ef32b3e34f6dcbbf08937e4f616.tar.xz
fs: rename current get acl method
The current way of setting and getting posix acls through the generic xattr interface is error prone and type unsafe. The vfs needs to interpret and fixup posix acls before storing or reporting it to userspace. Various hacks exist to make this work. The code is hard to understand and difficult to maintain in it's current form. Instead of making this work by hacking posix acls through xattr handlers we are building a dedicated posix acl api around the get and set inode operations. This removes a lot of hackiness and makes the codepaths easier to maintain. A lot of background can be found in [1]. The current inode operation for getting posix acls takes an inode argument but various filesystems (e.g., 9p, cifs, overlayfs) need access to the dentry. In contrast to the ->set_acl() inode operation we cannot simply extend ->get_acl() to take a dentry argument. The ->get_acl() inode operation is called from: acl_permission_check() -> check_acl() -> get_acl() which is part of generic_permission() which in turn is part of inode_permission(). Both generic_permission() and inode_permission() are called in the ->permission() handler of various filesystems (e.g., overlayfs). So simply passing a dentry argument to ->get_acl() would amount to also having to pass a dentry argument to ->permission(). We should avoid this unnecessary change. So instead of extending the existing inode operation rename it from ->get_acl() to ->get_inode_acl() and add a ->get_acl() method later that passes a dentry argument and which filesystems that need access to the dentry can implement instead of ->get_inode_acl(). Filesystems like cifs which allow setting and getting posix acls but not using them for permission checking during lookup can simply not implement ->get_inode_acl(). This is intended to be a non-functional change. Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1] Suggested-by/Inspired-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/dir.c2
-rw-r--r--fs/overlayfs/inode.c6
2 files changed, 4 insertions, 4 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 6b03457f72bb..7bece7010c00 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -1311,7 +1311,7 @@ const struct inode_operations ovl_dir_inode_operations = {
.permission = ovl_permission,
.getattr = ovl_getattr,
.listxattr = ovl_listxattr,
- .get_acl = ovl_get_acl,
+ .get_inode_acl = ovl_get_acl,
.update_time = ovl_update_time,
.fileattr_get = ovl_fileattr_get,
.fileattr_set = ovl_fileattr_set,
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 9e61511de7a7..6eefd8b7868e 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -517,7 +517,7 @@ struct posix_acl *ovl_get_acl(struct inode *inode, int type, bool rcu)
const struct cred *old_cred;
old_cred = ovl_override_creds(inode->i_sb);
- acl = get_acl(realinode, type);
+ acl = get_inode_acl(realinode, type);
revert_creds(old_cred);
}
/*
@@ -721,7 +721,7 @@ static const struct inode_operations ovl_file_inode_operations = {
.permission = ovl_permission,
.getattr = ovl_getattr,
.listxattr = ovl_listxattr,
- .get_acl = ovl_get_acl,
+ .get_inode_acl = ovl_get_acl,
.update_time = ovl_update_time,
.fiemap = ovl_fiemap,
.fileattr_get = ovl_fileattr_get,
@@ -741,7 +741,7 @@ static const struct inode_operations ovl_special_inode_operations = {
.permission = ovl_permission,
.getattr = ovl_getattr,
.listxattr = ovl_listxattr,
- .get_acl = ovl_get_acl,
+ .get_inode_acl = ovl_get_acl,
.update_time = ovl_update_time,
};