ovl: Switch to generic_removexattr

Commit d837a49bd57f ("ovl: fix POSIX ACL setting") switches from
iop->setxattr from ovl_setxattr to generic_setxattr, so switch from
ovl_removexattr to generic_removexattr as well.  As far as permission
checking goes, the same rules should apply in either case.

While doing that, rename ovl_setxattr to ovl_xattr_set to indicate that
this is not an iop->setxattr implementation and remove the unused inode
argument.

Move ovl_other_xattr_set above ovl_own_xattr_set so that they match the
order of handlers in ovl_xattr_handlers.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Fixes: d837a49bd57f ("ovl: fix POSIX ACL setting")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

4 files changed, 33 insertions, 58 deletions

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index f485dd4288e4..791c6a209656 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -1006,7 +1006,7 @@ const struct inode_operations ovl_dir_inode_operations = {
         .setxattr       = generic_setxattr,
         .getxattr       = ovl_getxattr,
         .listxattr      = ovl_listxattr,
-        .removexattr    = ovl_removexattr,
+        .removexattr    = generic_removexattr,
         .get_acl        = ovl_get_acl,
         .update_time    = ovl_update_time,
 };
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index f523511b324f..94bca710e6d2 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -198,25 +198,38 @@ bool ovl_is_private_xattr(const char *name)
                        sizeof(OVL_XATTR_PREFIX) - 1) == 0;
 }
 
-int ovl_setxattr(struct dentry *dentry, struct inode *inode,
-                 const char *name, const void *value,
-                 size_t size, int flags)
+int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
+                  size_t size, int flags)
 {
         int err;
-        struct dentry *upperdentry;
+        struct path realpath;
+        enum ovl_path_type type = ovl_path_real(dentry, &realpath);
         const struct cred *old_cred;
 
         err = ovl_want_write(dentry);
         if (err)
                 goto out;
 
+        if (!value && !OVL_TYPE_UPPER(type)) {
+                err = vfs_getxattr(realpath.dentry, name, NULL, 0);
+                if (err < 0)
+                        goto out_drop_write;
+        }
+
         err = ovl_copy_up(dentry);
         if (err)
                 goto out_drop_write;
 
-        upperdentry = ovl_dentry_upper(dentry);
+        if (!OVL_TYPE_UPPER(type))
+                ovl_path_upper(dentry, &realpath);
+
         old_cred = ovl_override_creds(dentry->d_sb);
-        err = vfs_setxattr(upperdentry, name, value, size, flags);
+        if (value)
+                err = vfs_setxattr(realpath.dentry, name, value, size, flags);
+        else {
+                WARN_ON(flags != XATTR_REPLACE);
+                err = vfs_removexattr(realpath.dentry, name);
+        }
         revert_creds(old_cred);
 
 out_drop_write:
@@ -272,42 +285,6 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
         return res;
 }
 
-int ovl_removexattr(struct dentry *dentry, const char *name)
-{
-        int err;
-        struct path realpath;
-        enum ovl_path_type type = ovl_path_real(dentry, &realpath);
-        const struct cred *old_cred;
-
-        err = ovl_want_write(dentry);
-        if (err)
-                goto out;
-
-        err = -ENODATA;
-        if (ovl_is_private_xattr(name))
-                goto out_drop_write;
-
-        if (!OVL_TYPE_UPPER(type)) {
-                err = vfs_getxattr(realpath.dentry, name, NULL, 0);
-                if (err < 0)
-                        goto out_drop_write;
-
-                err = ovl_copy_up(dentry);
-                if (err)
-                        goto out_drop_write;
-
-                ovl_path_upper(dentry, &realpath);
-        }
-
-        old_cred = ovl_override_creds(dentry->d_sb);
-        err = vfs_removexattr(realpath.dentry, name);
-        revert_creds(old_cred);
-out_drop_write:
-        ovl_drop_write(dentry);
-out:
-        return err;
-}
-
 struct posix_acl *ovl_get_acl(struct inode *inode, int type)
 {
         struct inode *realinode = ovl_inode_real(inode, NULL);
@@ -393,7 +370,7 @@ static const struct inode_operations ovl_file_inode_operations = {
         .setxattr       = generic_setxattr,
         .getxattr       = ovl_getxattr,
         .listxattr      = ovl_listxattr,
-        .removexattr    = ovl_removexattr,
+        .removexattr    = generic_removexattr,
         .get_acl        = ovl_get_acl,
         .update_time    = ovl_update_time,
 };
@@ -406,7 +383,7 @@ static const struct inode_operations ovl_symlink_inode_operations = {
         .setxattr       = generic_setxattr,
         .getxattr       = ovl_getxattr,
         .listxattr      = ovl_listxattr,
-        .removexattr    = ovl_removexattr,
+        .removexattr    = generic_removexattr,
         .update_time    = ovl_update_time,
 };
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index f50c390683a3..5769aaf151a3 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -185,13 +185,11 @@ void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 /* inode.c */
 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
 int ovl_permission(struct inode *inode, int mask);
-int ovl_setxattr(struct dentry *dentry, struct inode *inode,
-                 const char *name, const void *value,
-                 size_t size, int flags);
+int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value,
+                  size_t size, int flags);
 ssize_t ovl_getxattr(struct dentry *dentry, struct inode *inode,
                      const char *name, void *value, size_t size);
 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
-int ovl_removexattr(struct dentry *dentry, const char *name);
 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags);
 int ovl_update_time(struct inode *inode, struct timespec *ts, int flags);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index c35619195385..45a2eb0b4693 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1018,21 +1018,13 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
 
         posix_acl_release(acl);
 
-        return ovl_setxattr(dentry, inode, handler->name, value, size, flags);
+        return ovl_xattr_set(dentry, handler->name, value, size, flags);
 
 out_acl_release:
         posix_acl_release(acl);
         return err;
 }
 
-static int ovl_other_xattr_set(const struct xattr_handler *handler,
-                               struct dentry *dentry, struct inode *inode,
-                               const char *name, const void *value,
-                               size_t size, int flags)
-{
-        return ovl_setxattr(dentry, inode, name, value, size, flags);
-}
-
 static int ovl_own_xattr_set(const struct xattr_handler *handler,
                              struct dentry *dentry, struct inode *inode,
                              const char *name, const void *value,
@@ -1041,6 +1033,14 @@ static int ovl_own_xattr_set(const struct xattr_handler *handler,
         return -EPERM;
 }
 
+static int ovl_other_xattr_set(const struct xattr_handler *handler,
+                               struct dentry *dentry, struct inode *inode,
+                               const char *name, const void *value,
+                               size_t size, int flags)
+{
+        return ovl_xattr_set(dentry, name, value, size, flags);
+}
+
 static const struct xattr_handler __maybe_unused
 ovl_posix_acl_access_xattr_handler = {
         .name = XATTR_NAME_POSIX_ACL_ACCESS,