[PATCH] xattr: infrastructure for permission overrides

Patch from Andreas Gruenbacher <agruen@suse.de>

This adds flags parameters to the getxattr, listxattr, and removexattr inode
operations.  This is in preparation for the next patch, which allows
in-kernel code (i.e., modules) to override extended attribute permission
restrictions (which in turn is used by HSM implementations and the like).

fs/ext2/acl.c

@@ -419,7 +419,7 @@ ext2_acl_chmod(struct inode *inode)
  */
 static size_t
 ext2_xattr_list_acl_access(char *list, struct inode *inode,
-			   const char *name, int name_len)
+			   const char *name, int name_len, int flags)
 {
 	const size_t size = sizeof(XATTR_NAME_ACL_ACCESS);
 
@@ -432,7 +432,7 @@ ext2_xattr_list_acl_access(char *list, struct inode *inode,
 
 static size_t
 ext2_xattr_list_acl_default(char *list, struct inode *inode,
-			    const char *name, int name_len)
+			    const char *name, int name_len, int flags)
 {
 	const size_t size = sizeof(XATTR_NAME_ACL_DEFAULT);
 
@@ -465,7 +465,7 @@ ext2_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
 
 static int
 ext2_xattr_get_acl_access(struct inode *inode, const char *name,
-			  void *buffer, size_t size)
+			  void *buffer, size_t size, int flags)
 {
 	if (strcmp(name, "") != 0)
 		return -EINVAL;
@@ -474,7 +474,7 @@ ext2_xattr_get_acl_access(struct inode *inode, const char *name,
 
 static int
 ext2_xattr_get_acl_default(struct inode *inode, const char *name,
-			   void *buffer, size_t size)
+			   void *buffer, size_t size, int flags)
 {
 	if (strcmp(name, "") != 0)
 		return -EINVAL;
@@ -482,7 +482,8 @@ ext2_xattr_get_acl_default(struct inode *inode, const char *name,
 }
 
 static int
-ext2_xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
+ext2_xattr_set_acl(struct inode *inode, int type, const void *value,
+		   size_t size)
 {
 	struct posix_acl *acl;
 	int error;

fs/ext2/xattr.c

@@ -199,7 +199,7 @@ ext2_xattr_handler(int name_index)
  */
 ssize_t
 ext2_getxattr(struct dentry *dentry, const char *name,
-	      void *buffer, size_t size)
+	      void *buffer, size_t size, int flags)
 {
 	struct ext2_xattr_handler *handler;
 	struct inode *inode = dentry->d_inode;
@@ -207,7 +207,7 @@ ext2_getxattr(struct dentry *dentry, const char *name,
 	handler = ext2_xattr_resolve_name(&name);
 	if (!handler)
 		return -EOPNOTSUPP;
-	return handler->get(inode, name, buffer, size);
+	return handler->get(inode, name, buffer, size, flags);
 }
 
 /*
@@ -217,9 +217,9 @@ ext2_getxattr(struct dentry *dentry, const char *name,
  * BKL held [before 2.5.x]
  */
 ssize_t
-ext2_listxattr(struct dentry *dentry, char *buffer, size_t size)
+ext2_listxattr(struct dentry *dentry, char *buffer, size_t size, int flags)
 {
-	return ext2_xattr_list(dentry->d_inode, buffer, size);
+	return ext2_xattr_list(dentry->d_inode, buffer, size, flags);
 }
 
 /*
@@ -250,7 +250,7 @@ ext2_setxattr(struct dentry *dentry, const char *name,
  * BKL held [before 2.5.x]
  */
 int
-ext2_removexattr(struct dentry *dentry, const char *name)
+ext2_removexattr(struct dentry *dentry, const char *name, int flags)
 {
 	struct ext2_xattr_handler *handler;
 	struct inode *inode = dentry->d_inode;
@@ -258,7 +258,7 @@ ext2_removexattr(struct dentry *dentry, const char *name)
 	handler = ext2_xattr_resolve_name(&name);
 	if (!handler)
 		return -EOPNOTSUPP;
-	return handler->set(inode, name, NULL, 0, XATTR_REPLACE);
+	return handler->set(inode, name, NULL, 0, flags | XATTR_REPLACE);
 }
 
 /*
@@ -371,7 +371,8 @@ bad_block:	ext2_error(inode->i_sb, "ext2_xattr_get",
  * used / required on success.
  */
 int
-ext2_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
+ext2_xattr_list(struct inode *inode, char *buffer, size_t buffer_size,
+		int flags)
 {
 	struct buffer_head *bh = NULL;
 	struct ext2_xattr_entry *entry;
@@ -411,7 +412,7 @@ bad_block:	ext2_error(inode->i_sb, "ext2_xattr_list",
 		handler = ext2_xattr_handler(entry->e_name_index);
 		if (handler)
 			size += handler->list(NULL, inode, entry->e_name,
-					      entry->e_name_len);
+					      entry->e_name_len, flags);
 	}
 
 	if (ext2_xattr_cache_insert(bh))
@@ -434,7 +435,7 @@ bad_block:	ext2_error(inode->i_sb, "ext2_xattr_list",
 		handler = ext2_xattr_handler(entry->e_name_index);
 		if (handler)
 			buf += handler->list(buf, inode, entry->e_name,
-					     entry->e_name_len);
+					     entry->e_name_len, flags);
 	}
 	error = size;
 

fs/ext2/xattr.h

@@ -57,9 +57,9 @@ struct ext2_xattr_entry {
 struct ext2_xattr_handler {
 	char *prefix;
 	size_t (*list)(char *list, struct inode *inode, const char *name,
-		       int name_len);
+		       int name_len, int flags);
 	int (*get)(struct inode *inode, const char *name, void *buffer,
-		   size_t size);
+		   size_t size, int flags);
 	int (*set)(struct inode *inode, const char *name, const void *buffer,
 		   size_t size, int flags);
 };
@@ -68,12 +68,12 @@ extern int ext2_xattr_register(int, struct ext2_xattr_handler *);
 extern void ext2_xattr_unregister(int, struct ext2_xattr_handler *);
 
 extern int ext2_setxattr(struct dentry *, const char *, const void *, size_t, int);
-extern ssize_t ext2_getxattr(struct dentry *, const char *, void *, size_t);
-extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
-extern int ext2_removexattr(struct dentry *, const char *);
+extern ssize_t ext2_getxattr(struct dentry *, const char *, void *, size_t, int);
+extern ssize_t ext2_listxattr(struct dentry *, char *, size_t, int);
+extern int ext2_removexattr(struct dentry *, const char *, int);
 
 extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
-extern int ext2_xattr_list(struct inode *, char *, size_t);
+extern int ext2_xattr_list(struct inode *, char *, size_t, int flags);
 extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 
 extern void ext2_xattr_delete_inode(struct inode *);

fs/ext2/xattr_user.c

@@ -19,7 +19,7 @@
 
 static size_t
 ext2_xattr_user_list(char *list, struct inode *inode,
-		     const char *name, int name_len)
+		     const char *name, int name_len, int flags)
 {
 	const int prefix_len = sizeof(XATTR_USER_PREFIX)-1;
 
@@ -36,7 +36,7 @@ ext2_xattr_user_list(char *list, struct inode *inode,
 
 static int
 ext2_xattr_user_get(struct inode *inode, const char *name,
-		    void *buffer, size_t size)
+		    void *buffer, size_t size, int flags)
 {
 	int error;
 

fs/ext3/acl.c

@@ -431,7 +431,7 @@ ext3_acl_chmod(struct inode *inode)
  */
 static size_t
 ext3_xattr_list_acl_access(char *list, struct inode *inode,
-			   const char *name, int name_len)
+			   const char *name, int name_len, int flags)
 {
 	const size_t size = sizeof(XATTR_NAME_ACL_ACCESS);
 
@@ -444,7 +444,7 @@ ext3_xattr_list_acl_access(char *list, struct inode *inode,
 
 static size_t
 ext3_xattr_list_acl_default(char *list, struct inode *inode,
-			    const char *name, int name_len)
+			    const char *name, int name_len, int flags)
 {
 	const size_t size = sizeof(XATTR_NAME_ACL_DEFAULT);
 
@@ -477,7 +477,7 @@ ext3_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
 
 static int
 ext3_xattr_get_acl_access(struct inode *inode, const char *name,
-			  void *buffer, size_t size)
+			  void *buffer, size_t size, int flags)
 {
 	if (strcmp(name, "") != 0)
 		return -EINVAL;
@@ -486,7 +486,7 @@ ext3_xattr_get_acl_access(struct inode *inode, const char *name,
 
 static int
 ext3_xattr_get_acl_default(struct inode *inode, const char *name,
-			   void *buffer, size_t size)
+			   void *buffer, size_t size, int flags)
 {
 	if (strcmp(name, "") != 0)
 		return -EINVAL;
@@ -494,7 +494,8 @@ ext3_xattr_get_acl_default(struct inode *inode, const char *name,
 }
 
 static int
-ext3_xattr_set_acl(struct inode *inode, int type, const void *value, size_t size)
+ext3_xattr_set_acl(struct inode *inode, int type, const void *value,
+		   size_t size)
 {
 	handle_t *handle;
 	struct posix_acl *acl;

fs/ext3/xattr.c

@@ -195,7 +195,7 @@ ext3_xattr_handler(int name_index)
  */
 ssize_t
 ext3_getxattr(struct dentry *dentry, const char *name,
-	      void *buffer, size_t size)
+	      void *buffer, size_t size, int flags)
 {
 	struct ext3_xattr_handler *handler;
 	struct inode *inode = dentry->d_inode;
@@ -203,7 +203,7 @@ ext3_getxattr(struct dentry *dentry, const char *name,
 	handler = ext3_xattr_resolve_name(&name);
 	if (!handler)
 		return -EOPNOTSUPP;
-	return handler->get(inode, name, buffer, size);
+	return handler->get(inode, name, buffer, size, flags);
 }
 
 /*
@@ -212,9 +212,9 @@ ext3_getxattr(struct dentry *dentry, const char *name,
  * dentry->d_inode->i_sem down
  */
 ssize_t
-ext3_listxattr(struct dentry *dentry, char *buffer, size_t size)
+ext3_listxattr(struct dentry *dentry, char *buffer, size_t size, int flags)
 {
-	return ext3_xattr_list(dentry->d_inode, buffer, size);
+	return ext3_xattr_list(dentry->d_inode, buffer, size, flags);
 }
 
 /*
@@ -243,7 +243,7 @@ ext3_setxattr(struct dentry *dentry, const char *name,
  * dentry->d_inode->i_sem down
  */
 int
-ext3_removexattr(struct dentry *dentry, const char *name)
+ext3_removexattr(struct dentry *dentry, const char *name, int flags)
 {
 	struct ext3_xattr_handler *handler;
 	struct inode *inode = dentry->d_inode;
@@ -251,7 +251,7 @@ ext3_removexattr(struct dentry *dentry, const char *name)
 	handler = ext3_xattr_resolve_name(&name);
 	if (!handler)
 		return -EOPNOTSUPP;
-	return handler->set(inode, name, NULL, 0, XATTR_REPLACE);
+	return handler->set(inode, name, NULL, 0, flags | XATTR_REPLACE);
 }
 
 /*
@@ -364,7 +364,8 @@ bad_block:	ext3_error(inode->i_sb, "ext3_xattr_get",
  * used / required on success.
  */
 int
-ext3_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
+ext3_xattr_list(struct inode *inode, char *buffer, size_t buffer_size,
+		int flags)
 {
 	struct buffer_head *bh = NULL;
 	struct ext3_xattr_entry *entry;
@@ -404,7 +405,7 @@ bad_block:	ext3_error(inode->i_sb, "ext3_xattr_list",
 		handler = ext3_xattr_handler(entry->e_name_index);
 		if (handler)
 			size += handler->list(NULL, inode, entry->e_name,
-					      entry->e_name_len);
+					      entry->e_name_len, flags);
 	}
 
 	if (ext3_xattr_cache_insert(bh))
@@ -427,7 +428,7 @@ bad_block:	ext3_error(inode->i_sb, "ext3_xattr_list",
 		handler = ext3_xattr_handler(entry->e_name_index);
 		if (handler)
 			buf += handler->list(buf, inode, entry->e_name,
-					     entry->e_name_len);
+					     entry->e_name_len, flags);
 	}
 	error = size;
 

fs/ext3/xattr.h

@@ -56,9 +56,9 @@ struct ext3_xattr_entry {
 struct ext3_xattr_handler {
 	char *prefix;
 	size_t (*list)(char *list, struct inode *inode, const char *name,
-		       int name_len);
+		       int name_len, int flags);
 	int (*get)(struct inode *inode, const char *name, void *buffer,
-		   size_t size);
+		   size_t size, int flags);
 	int (*set)(struct inode *inode, const char *name, const void *buffer,
 		   size_t size, int flags);
 };
@@ -67,12 +67,12 @@ extern int ext3_xattr_register(int, struct ext3_xattr_handler *);
 extern void ext3_xattr_unregister(int, struct ext3_xattr_handler *);
 
 extern int ext3_setxattr(struct dentry *, const char *, const void *, size_t, int);
-extern ssize_t ext3_getxattr(struct dentry *, const char *, void *, size_t);
-extern ssize_t ext3_listxattr(struct dentry *, char *, size_t);
-extern int ext3_removexattr(struct dentry *, const char *);
+extern ssize_t ext3_getxattr(struct dentry *, const char *, void *, size_t, int);
+extern ssize_t ext3_listxattr(struct dentry *, char *, size_t, int);
+extern int ext3_removexattr(struct dentry *, const char *, int);
 
 extern int ext3_xattr_get(struct inode *, int, const char *, void *, size_t);
-extern int ext3_xattr_list(struct inode *, char *, size_t);
+extern int ext3_xattr_list(struct inode *, char *, size_t, int flags);
 extern int ext3_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 extern int ext3_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
 

fs/ext3/xattr_user.c

@@ -21,7 +21,7 @@
 
 static size_t
 ext3_xattr_user_list(char *list, struct inode *inode,
-		     const char *name, int name_len)
+		     const char *name, int name_len, int flags)
 {
 	const int prefix_len = sizeof(XATTR_USER_PREFIX)-1;
 
@@ -38,7 +38,7 @@ ext3_xattr_user_list(char *list, struct inode *inode,
 
 static int
 ext3_xattr_user_get(struct inode *inode, const char *name,
-		    void *buffer, size_t size)
+		    void *buffer, size_t size, int flags)
 {
 	int error;
 

fs/jfs/jfs_xattr.h

@@ -57,8 +57,8 @@ extern int __jfs_setxattr(struct inode *, const char *, const void *, size_t,
 extern int jfs_setxattr(struct dentry *, const char *, const void *, size_t,
 			int);
 extern ssize_t __jfs_getxattr(struct inode *, const char *, void *, size_t);
-extern ssize_t jfs_getxattr(struct dentry *, const char *, void *, size_t);
-extern ssize_t jfs_listxattr(struct dentry *, char *, size_t);
-extern int jfs_removexattr(struct dentry *, const char *);
+extern ssize_t jfs_getxattr(struct dentry *, const char *, void *, size_t, int);
+extern ssize_t jfs_listxattr(struct dentry *, char *, size_t, int);
+extern int jfs_removexattr(struct dentry *, const char *, int);
 
 #endif	/* H_JFS_XATTR */

fs/jfs/xattr.c

@@ -962,12 +962,13 @@ ssize_t __jfs_getxattr(struct inode *inode, const char *name, void *data,
 }
 
 ssize_t jfs_getxattr(struct dentry *dentry, const char *name, void *data,
-		     size_t buf_size)
+		     size_t buf_size, int flags)
 {
 	return __jfs_getxattr(dentry->d_inode, name, data, buf_size);
 }
 
-ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size)
+ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size,
+		      int flags)
 {
 	struct inode *inode = dentry->d_inode;
 	char *buffer;
@@ -1013,7 +1014,7 @@ ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size)
 	return size;
 }
 
-int jfs_removexattr(struct dentry *dentry, const char *name)
+int jfs_removexattr(struct dentry *dentry, const char *name, int flags)
 {
 	return __jfs_setxattr(dentry->d_inode, name, 0, 0, XATTR_REPLACE);
 }

fs/xattr.c

@@ -160,7 +160,7 @@ getxattr(struct dentry *d, char *name, void *value, size_t size)
 		if (error)
 			goto out;
 		down(&d->d_inode->i_sem);
-		error = d->d_inode->i_op->getxattr(d, kname, kvalue, size);
+		error = d->d_inode->i_op->getxattr(d, kname, kvalue, size, 0);
 		up(&d->d_inode->i_sem);
 	}
 
@@ -233,7 +233,7 @@ listxattr(struct dentry *d, char *list, size_t size)
 		if (error)
 			goto out;
 		down(&d->d_inode->i_sem);
-		error = d->d_inode->i_op->listxattr(d, klist, size);
+		error = d->d_inode->i_op->listxattr(d, klist, size, 0);
 		up(&d->d_inode->i_sem);
 	}
 
@@ -308,7 +308,7 @@ removexattr(struct dentry *d, char *name)
 		if (error)
 			goto out;
 		down(&d->d_inode->i_sem);
-		error = d->d_inode->i_op->removexattr(d, kname);
+		error = d->d_inode->i_op->removexattr(d, kname, 0);
 		up(&d->d_inode->i_sem);
 	}
 out:

fs/xfs/linux/xfs_iops.c

@@ -640,7 +640,8 @@ linvfs_getxattr(
 	struct dentry	*dentry,
 	const char	*name,
 	void		*data,
-	size_t		size)
+	size_t		size,
+	int		flags)
 {
 	ssize_t		error;
 	int		xflags = 0;
@@ -697,7 +698,8 @@ STATIC ssize_t
 linvfs_listxattr(
 	struct dentry		*dentry,
 	char			*data,
-	size_t			size)
+	size_t			size,
+	int			flags)
 {
 	ssize_t			error;
 	int			result = 0;
@@ -741,7 +743,8 @@ linvfs_listxattr(
 STATIC int
 linvfs_removexattr(
 	struct dentry	*dentry,
-	const char	*name)
+	const char	*name,
+	int		flags)
 {
 	int		error;
 	int		xflags = 0;

include/linux/fs.h

@@ -743,9 +743,9 @@ struct inode_operations {
 	int (*setattr) (struct dentry *, struct iattr *);
 	int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
 	int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
-	ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
-	ssize_t (*listxattr) (struct dentry *, char *, size_t);
-	int (*removexattr) (struct dentry *, const char *);
+	ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t,int);
+	ssize_t (*listxattr) (struct dentry *, char *, size_t, int);
+	int (*removexattr) (struct dentry *, const char *, int);
 };
 
 struct seq_file;