• Sripathi Kodi's avatar
    9p: readdir implementation for 9p2000.L · 7751bdb3
    Sripathi Kodi authored
    This patch implements the kernel part of readdir() implementation for 9p2000.L
    
        Change from V3: Instead of inode, server now sends qids for each dirent
    
        SYNOPSIS
    
        size[4] Treaddir tag[2] fid[4] offset[8] count[4]
        size[4] Rreaddir tag[2] count[4] data[count]
    
        DESCRIPTION
    
        The readdir request asks the server to read the directory specified by 'fid'
        at an offset specified by 'offset' and return as many dirent structures as
        possible that fit into count bytes. Each dirent structure is laid out as
        follows.
    
                qid.type[1]
                  the type of the file (directory, etc.), represented as a bit
                  vector corresponding to the high 8 bits of the file's mode
                  word.
    
                qid.vers[4]
                  version number for given path
    
                qid.path[8]
                  the file server's unique identification for the file
    
                offset[8]
                  offset into the next dirent.
    
                type[1]
                  type of this directory entry.
    
                name[256]
                  name of this directory entry.
    
        This patch adds v9fs_dir_readdir_dotl() as the readdir() call for 9p2000.L.
        This function sends P9_TREADDIR command to the server. In response the server
        sends a buffer filled with dirent structures. This is different from the
        existing v9fs_dir_readdir() call which receives stat structures from the server.
        This results in significant speedup of readdir() on large directories.
        For example, doing 'ls >/dev/null' on a directory with 10000 files on my
        laptop takes 1.088 seconds with the existing code, but only takes 0.339 seconds
        with the new readdir.
    Signed-off-by: default avatarSripathi Kodi <sripathik@in.ibm.com>
    Reviewed-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
    Signed-off-by: default avatarEric Van Hensbergen <ericvh@gmail.com>
    7751bdb3
vfs_dir.c 6.88 KB