diff options
Diffstat (limited to 'Documentation/filesystems/vfs.txt')
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 45 |
1 files changed, 30 insertions, 15 deletions
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index cbec006e10e4..43ef86c266ec 100644 --- 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. +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 ================ @@ -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 (*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 *); 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. - 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 - 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 |