Merge branch 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[cascardo/linux.git] / Documentation / filesystems / vfs.txt

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index cbec006..43ef86c 100644 (file)
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -323,6 +323,35 @@ Whoever sets up the inode is responsible for filling in the "i_op" field. This
 is a pointer to a "struct inode_operations" which describes the methods that
 can be performed on individual inodes.
 
 is a pointer to a "struct inode_operations" which describes the methods that
 can be performed on individual inodes.
 

+struct xattr_handlers
+---------------------
+
+On filesystems that support extended attributes (xattrs), the s_xattr
+superblock field points to a NULL-terminated array of xattr handlers.  Extended
+attributes are name:value pairs.
+
+  name: Indicates that the handler matches attributes with the specified name
+       (such as "system.posix_acl_access"); the prefix field must be NULL.
+
+  prefix: Indicates that the handler matches all attributes with the specified
+       name prefix (such as "user."); the name field must be NULL.
+
+  list: Determine if attributes matching this xattr handler should be listed
+       for a particular dentry.  Used by some listxattr implementations like
+       generic_listxattr.
+
+  get: Called by the VFS to get the value of a particular extended attribute.
+       This method is called by the getxattr(2) system call.
+
+  set: Called by the VFS to set the value of a particular extended attribute.
+       When the new value is NULL, called to remove a particular extended
+       attribute.  This method is called by the the setxattr(2) and
+       removexattr(2) system calls.
+
+When none of the xattr handlers of a filesystem match the specified attribute
+name or when a filesystem doesn't support extended attributes, the various
+*xattr(2) system calls return -EOPNOTSUPP.
+

 
 The Inode Object
 ================
 
 The Inode Object
 ================


@@ -356,10 +385,7 @@ struct inode_operations {
        int (*get_acl)(struct inode *, int);
        int (*setattr) (struct dentry *, struct iattr *);
        int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
        int (*get_acl)(struct inode *, int);
        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);
        ssize_t (*listxattr) (struct dentry *, char *, size_t);

-       int (*removexattr) (struct dentry *, const char *);

        void (*update_time)(struct inode *, struct timespec *, int);
        int (*atomic_open)(struct inode *, struct dentry *, struct file *,
                        unsigned open_flag, umode_t create_mode, int *opened);
        void (*update_time)(struct inode *, struct timespec *, int);
        int (*atomic_open)(struct inode *, struct dentry *, struct file *,
                        unsigned open_flag, umode_t create_mode, int *opened);


@@ -463,19 +489,8 @@ otherwise noted.
   getattr: called by the VFS to get attributes of a file. This method
        is called by stat(2) and related system calls.
 
   getattr: called by the VFS to get attributes of a file. This method
        is called by stat(2) and related system calls.
 

-  setxattr: called by the VFS to set an extended attribute for a file.
-       Extended attribute is a name:value pair associated with an
-       inode. This method is called by setxattr(2) system call.
-
-  getxattr: called by the VFS to retrieve the value of an extended
-       attribute name. This method is called by getxattr(2) function
-       call.
-

   listxattr: called by the VFS to list all extended attributes for a
   listxattr: called by the VFS to list all extended attributes for a

-       given file. This method is called by listxattr(2) system call.
-
-  removexattr: called by the VFS to remove an extended attribute from
-       a file. This method is called by removexattr(2) system call.
+       given file. This method is called by the listxattr(2) system call.

 
   update_time: called by the VFS to update a specific time or the i_version of
        an inode.  If this is not defined the VFS will update the inode itself
 
   update_time: called by the VFS to update a specific time or the i_version of
        an inode.  If this is not defined the VFS will update the inode itself