xattr: Add __vfs_{get,set,remove}xattr helpers

Right now, various places in the kernel check for the existence of
getxattr, setxattr, and removexattr inode operations and directly call
those operations. Switch to helper functions and test for the IOP_XATTR
flag instead.

Signed-off-by: Andreas Gruenbacher <[e-mail]>
Acked-by: James Morris <[e-mail]>
Signed-off-by: Al Viro <[e-mail]>

fs/cachefiles/bind.c

···
 #include <linux/mount.h>
 #include <linux/statfs.h>
 #include <linux/ctype.h>
+#include <linux/xattr.h>
 #include "internal.h"
 
 static int cachefiles_daemon_add_cache(struct cachefiles_cache *caches);
···
 	if (d_is_negative(root) ||
 	    !d_backing_inode(root)->i_op->lookup ||
 	    !d_backing_inode(root)->i_op->mkdir ||
-	    !d_backing_inode(root)->i_op->setxattr ||
-	    !d_backing_inode(root)->i_op->getxattr ||
+	    !(d_backing_inode(root)->i_opflags & IOP_XATTR) ||
 	    !root->d_sb->s_op->statfs ||
 	    !root->d_sb->s_op->sync_fs)
 		goto error_unsupported;

fs/cachefiles/namei.c

···
 #include <linux/namei.h>
 #include <linux/security.h>
 #include <linux/slab.h>
+#include <linux/xattr.h>
 #include "internal.h"
 
 #define CACHEFILES_KEYBUF_SIZE 512
···
 	}
 
 	ret = -EPERM;
-	if (!d_backing_inode(subdir)->i_op->setxattr ||
-	    !d_backing_inode(subdir)->i_op->getxattr ||
+	if (!(d_backing_inode(subdir)->i_opflags & IOP_XATTR) ||
 	    !d_backing_inode(subdir)->i_op->lookup ||
 	    !d_backing_inode(subdir)->i_op->mkdir ||
 	    !d_backing_inode(subdir)->i_op->create ||

fs/ecryptfs/inode.c

···
 		  const char *name, const void *value,
 		  size_t size, int flags)
 {
-	int rc = 0;
+	int rc;
 	struct dentry *lower_dentry;
 
 	lower_dentry = ecryptfs_dentry_to_lower(dentry);
-	if (!d_inode(lower_dentry)->i_op->setxattr) {
+	if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
 		rc = -EOPNOTSUPP;
 		goto out;
 	}
-
 	rc = vfs_setxattr(lower_dentry, name, value, size, flags);
 	if (!rc && inode)
 		fsstack_copy_attr_all(inode, d_inode(lower_dentry));
···
 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
 			const char *name, void *value, size_t size)
 {
-	int rc = 0;
+	int rc;
 
-	if (!lower_inode->i_op->getxattr) {
+	if (!(lower_inode->i_opflags & IOP_XATTR)) {
 		rc = -EOPNOTSUPP;
 		goto out;
 	}
 	inode_lock(lower_inode);
-	rc = lower_inode->i_op->getxattr(lower_dentry, lower_inode,
-					 name, value, size);
+	rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
 	inode_unlock(lower_inode);
 out:
 	return rc;
···
 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
 				const char *name)
 {
-	int rc = 0;
+	int rc;
 	struct dentry *lower_dentry;
 	struct inode *lower_inode;
 
 	lower_dentry = ecryptfs_dentry_to_lower(dentry);
 	lower_inode = ecryptfs_inode_to_lower(inode);
-	if (!lower_inode->i_op->removexattr) {
+	if (!(lower_inode->i_opflags & IOP_XATTR)) {
 		rc = -EOPNOTSUPP;
 		goto out;
 	}
 	inode_lock(lower_inode);
-	rc = lower_inode->i_op->removexattr(lower_dentry, name);
+	rc = __vfs_removexattr(lower_dentry, name);
 	inode_unlock(lower_inode);
 out:
 	return rc;

fs/ecryptfs/mmap.c

···
 #include <linux/file.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
+#include <linux/xattr.h>
 #include <asm/unaligned.h>
 #include "ecryptfs_kernel.h"
 
···
 	struct inode *lower_inode = d_inode(lower_dentry);
 	int rc;
 
-	if (!lower_inode->i_op->getxattr || !lower_inode->i_op->setxattr) {
+	if (!(lower_inode->i_opflags & IOP_XATTR)) {
 		printk(KERN_WARNING
 		       "No support for setting xattr in lower filesystem\n");
 		rc = -ENOSYS;
···
 		goto out;
 	}
 	inode_lock(lower_inode);
-	size = lower_inode->i_op->getxattr(lower_dentry, lower_inode,
-					   ECRYPTFS_XATTR_NAME,
-					   xattr_virt, PAGE_SIZE);
+	size = __vfs_getxattr(lower_dentry, lower_inode, ECRYPTFS_XATTR_NAME,
+			      xattr_virt, PAGE_SIZE);
 	if (size < 0)
 		size = 8;
 	put_unaligned_be64(i_size_read(ecryptfs_inode), xattr_virt);
-	rc = lower_inode->i_op->setxattr(lower_dentry, lower_inode,
-					 ECRYPTFS_XATTR_NAME,
-					 xattr_virt, size, 0);
+	rc = __vfs_setxattr(lower_dentry, lower_inode, ECRYPTFS_XATTR_NAME,
+			    xattr_virt, size, 0);
 	inode_unlock(lower_inode);
 	if (rc)
 		printk(KERN_ERR "Error whilst attempting to write inode size "

fs/overlayfs/copy_up.c

···
 	char *buf, *name, *value = NULL;
 	int uninitialized_var(error);
 
-	if (!old->d_inode->i_op->getxattr ||
-	    !new->d_inode->i_op->getxattr)
+	if (!(old->d_inode->i_opflags & IOP_XATTR) ||
+	    !(new->d_inode->i_opflags & IOP_XATTR))
 		return 0;
 
 	list_size = vfs_listxattr(old, NULL, 0);

fs/overlayfs/super.c

···
 	char val;
 	struct inode *inode = dentry->d_inode;
 
-	if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr)
+	if (!S_ISDIR(inode->i_mode) || !(inode->i_opflags & IOP_XATTR))
 		return false;
 
-	res = inode->i_op->getxattr(dentry, inode, OVL_XATTR_OPAQUE, &val, 1);
+	res = __vfs_getxattr(dentry, inode, OVL_XATTR_OPAQUE, &val, 1);
 	if (res == 1 && val == 'y')
 		return true;
 

fs/xattr.c

···
 	return inode_permission(inode, mask);
 }
 
+int
+__vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
+	       const void *value, size_t size, int flags)
+{
+	if (!inode->i_op->setxattr)
+		return -EOPNOTSUPP;
+	return inode->i_op->setxattr(dentry, inode, name, value, size, flags);
+}
+EXPORT_SYMBOL(__vfs_setxattr);
+
 /**
  *  __vfs_setxattr_noperm - perform setxattr operation without performing
  *  permission checks.
···
 	if (issec)
 		inode->i_flags &= ~S_NOSEC;
 	if (inode->i_op->setxattr) {
-		error = inode->i_op->setxattr(dentry, inode, name, value, size, flags);
+		error = __vfs_setxattr(dentry, inode, name, value, size, flags);
 		if (!error) {
 			fsnotify_xattr(dentry);
 			security_inode_post_setxattr(dentry, name, value,
···
 }
 
 ssize_t
+__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name,
+	       void *value, size_t size)
+{
+	if (!inode->i_op->getxattr)
+		return -EOPNOTSUPP;
+	return inode->i_op->getxattr(dentry, inode, name, value, size);
+}
+EXPORT_SYMBOL(__vfs_getxattr);
+
+ssize_t
 vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
 {
 	struct inode *inode = dentry->d_inode;
···
 		return ret;
 	}
 nolsm:
-	if (inode->i_op->getxattr)
-		error = inode->i_op->getxattr(dentry, inode, name, value, size);
-	else
-		error = -EOPNOTSUPP;
-
-	return error;
-
+	return __vfs_getxattr(dentry, inode, name, value, size);
 }
 EXPORT_SYMBOL_GPL(vfs_getxattr);
 
···
 EXPORT_SYMBOL_GPL(vfs_listxattr);
 
 int
+__vfs_removexattr(struct dentry *dentry, const char *name)
+{
+	struct inode *inode = dentry->d_inode;
+
+	if (!inode->i_op->removexattr)
+		return -EOPNOTSUPP;
+	return inode->i_op->removexattr(dentry, name);
+}
+EXPORT_SYMBOL(__vfs_removexattr);
+
+int
 vfs_removexattr(struct dentry *dentry, const char *name)
 {
 	struct inode *inode = dentry->d_inode;
 	int error;
-
-	if (!inode->i_op->removexattr)
-		return -EOPNOTSUPP;
 
 	error = xattr_permission(inode, name, MAY_WRITE);
 	if (error)
···
 	if (error)
 		goto out;
 
-	error = inode->i_op->removexattr(dentry, name);
+	error = __vfs_removexattr(dentry, name);
 
 	if (!error) {
 		fsnotify_xattr(dentry);

include/linux/xattr.h

···
 };
 
 ssize_t xattr_getsecurity(struct inode *, const char *, void *, size_t);
+ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
 ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t);
 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
+int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int);
 int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int);
 int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int);
+int __vfs_removexattr(struct dentry *, const char *);
 int vfs_removexattr(struct dentry *, const char *);
 
 ssize_t generic_getxattr(struct dentry *dentry, struct inode *inode, const char *name, void *buffer, size_t size);

security/commoncap.c

···
 	struct inode *inode = d_backing_inode(dentry);
 	int error;
 
-	if (!inode->i_op->getxattr)
-	       return 0;
-
-	error = inode->i_op->getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
-	if (error <= 0)
-		return 0;
-	return 1;
+	error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
+	return error > 0;
 }
 
 /**
···
  */
 int cap_inode_killpriv(struct dentry *dentry)
 {
-	struct inode *inode = d_backing_inode(dentry);
+	int error;
 
-	if (!inode->i_op->removexattr)
-	       return 0;
-
-	return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
+	error = __vfs_removexattr(dentry, XATTR_NAME_CAPS);
+	if (error == -EOPNOTSUPP)
+		error = 0;
+	return error;
 }
 
 /*
···
 
 	memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
 
-	if (!inode || !inode->i_op->getxattr)
+	if (!inode)
 		return -ENODATA;
 
-	size = inode->i_op->getxattr((struct dentry *)dentry, inode,
-				     XATTR_NAME_CAPS, &caps, XATTR_CAPS_SZ);
+	size = __vfs_getxattr((struct dentry *)dentry, inode,
+			      XATTR_NAME_CAPS, &caps, XATTR_CAPS_SZ);
 	if (size == -ENODATA || size == -EOPNOTSUPP)
 		/* no data, that's ok */
 		return -ENODATA;

security/integrity/evm/evm_crypto.c

···
 	int error;
 	int size;
 
-	if (!inode->i_op->getxattr)
+	if (!(inode->i_opflags & IOP_XATTR))
 		return -EOPNOTSUPP;
+
 	desc = init_desc(type);
 	if (IS_ERR(desc))
 		return PTR_ERR(desc);
···
 		rc = __vfs_setxattr_noperm(dentry, XATTR_NAME_EVM,
 					   &xattr_data,
 					   sizeof(xattr_data), 0);
-	} else if (rc == -ENODATA && inode->i_op->removexattr) {
-		rc = inode->i_op->removexattr(dentry, XATTR_NAME_EVM);
+	} else if (rc == -ENODATA && (inode->i_opflags & IOP_XATTR)) {
+		rc = __vfs_removexattr(dentry, XATTR_NAME_EVM);
 	}
 	return rc;
 }

security/integrity/evm/evm_main.c

···
 	int error;
 	int count = 0;
 
-	if (!inode->i_op->getxattr)
+	if (!(inode->i_opflags & IOP_XATTR))
 		return -EOPNOTSUPP;
 
 	for (xattr = evm_config_xattrnames; *xattr != NULL; xattr++) {
-		error = inode->i_op->getxattr(dentry, inode, *xattr, NULL, 0);
+		error = __vfs_getxattr(dentry, inode, *xattr, NULL, 0);
 		if (error < 0) {
 			if (error == -ENODATA)
 				continue;

security/integrity/ima/ima_appraise.c

···
 int ima_read_xattr(struct dentry *dentry,
 		   struct evm_ima_xattr_data **xattr_value)
 {
-	struct inode *inode = d_backing_inode(dentry);
+	ssize_t ret;
 
-	if (!inode->i_op->getxattr)
-		return 0;
-
-	return vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)xattr_value,
-				  0, GFP_NOFS);
+	ret = vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)xattr_value,
+				 0, GFP_NOFS);
+	if (ret == -EOPNOTSUPP)
+		ret = 0;
+	return ret;
 }
 
 /*
···
 	enum integrity_status status = INTEGRITY_UNKNOWN;
 	int rc = xattr_len, hash_start = 0;
 
-	if (!inode->i_op->getxattr)
+	if (!(inode->i_opflags & IOP_XATTR))
 		return INTEGRITY_UNKNOWN;
 
 	if (rc <= 0) {
···
 {
 	struct inode *inode = d_backing_inode(dentry);
 	struct integrity_iint_cache *iint;
-	int must_appraise, rc;
+	int must_appraise;
 
 	if (!(ima_policy_flag & IMA_APPRAISE) || !S_ISREG(inode->i_mode)
-	    || !inode->i_op->removexattr)
+	    || !(inode->i_opflags & IOP_XATTR))
 		return;
 
 	must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR);
···
 			iint->flags |= IMA_APPRAISE;
 	}
 	if (!must_appraise)
-		rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA);
-	return;
+		__vfs_removexattr(dentry, XATTR_NAME_IMA);
 }
 
 /*

security/selinux/hooks.c

···
 		   the root directory.  -ENODATA is ok, as this may be
 		   the first boot of the SELinux kernel before we have
 		   assigned xattr values to the filesystem. */
-		if (!root_inode->i_op->getxattr) {
+		if (!(root_inode->i_opflags & IOP_XATTR)) {
 			printk(KERN_WARNING "SELinux: (dev %s, type %s) has no "
 			       "xattr support\n", sb->s_id, sb->s_type->name);
 			rc = -EOPNOTSUPP;
 			goto out;
 		}
-		rc = root_inode->i_op->getxattr(root, root_inode,
-						XATTR_NAME_SELINUX, NULL, 0);
+
+		rc = __vfs_getxattr(root, root_inode, XATTR_NAME_SELINUX, NULL, 0);
 		if (rc < 0 && rc != -ENODATA) {
 			if (rc == -EOPNOTSUPP)
 				printk(KERN_WARNING "SELinux: (dev %s, type "
···
 	case SECURITY_FS_USE_NATIVE:
 		break;
 	case SECURITY_FS_USE_XATTR:
-		if (!inode->i_op->getxattr) {
+		if (!(inode->i_opflags & IOP_XATTR)) {
 			isec->sid = sbsec->def_sid;
 			break;
 		}
-
 		/* Need a dentry, since the xattr API requires one.
 		   Life would be simpler if we could just pass the inode. */
 		if (opt_dentry) {
···
 			goto out_unlock;
 		}
 		context[len] = '\0';
-		rc = inode->i_op->getxattr(dentry, inode, XATTR_NAME_SELINUX,
-					   context, len);
+		rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
 		if (rc == -ERANGE) {
 			kfree(context);
 
 			/* Need a larger buffer.  Query for the right size. */
-			rc = inode->i_op->getxattr(dentry, inode, XATTR_NAME_SELINUX,
-						   NULL, 0);
+			rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0);
 			if (rc < 0) {
 				dput(dentry);
 				goto out_unlock;
···
 				goto out_unlock;
 			}
 			context[len] = '\0';
-			rc = inode->i_op->getxattr(dentry, inode,
-						   XATTR_NAME_SELINUX,
-						   context, len);
+			rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
 		}
 		dput(dentry);
 		if (rc < 0) {

security/smack/smack_lsm.c

···
 	char *buffer;
 	struct smack_known *skp = NULL;
 
-	if (ip->i_op->getxattr == NULL)
+	if (!(ip->i_opflags & IOP_XATTR))
 		return ERR_PTR(-EOPNOTSUPP);
 
 	buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL);
 	if (buffer == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	rc = ip->i_op->getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
+	rc = __vfs_getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
 	if (rc < 0)
 		skp = ERR_PTR(rc);
 	else if (rc == 0)
···
 		 * It would be curious if the label of the task
 		 * does not match that assigned.
 		 */
-		if (inode->i_op->getxattr == NULL)
-			break;
+		if (!(inode->i_opflags & IOP_XATTR))
+		        break;
 		/*
 		 * Get the dentry for xattr.
 		 */
···
 			 */
 			if (isp->smk_flags & SMK_INODE_CHANGED) {
 				isp->smk_flags &= ~SMK_INODE_CHANGED;
-				rc = inode->i_op->setxattr(dp, inode,
+				rc = __vfs_setxattr(dp, inode,
 					XATTR_NAME_SMACKTRANSMUTE,
 					TRANS_TRUE, TRANS_TRUE_SIZE,
 					0);
 			} else {
-				rc = inode->i_op->getxattr(dp, inode,
+				rc = __vfs_getxattr(dp, inode,
 					XATTR_NAME_SMACKTRANSMUTE, trattr,
 					TRANS_TRUE_SIZE);
 				if (rc >= 0 && strncmp(trattr, TRANS_TRUE,