FreeBSD/Linux Kernel Cross Reference
sys/fs/freevxfs/vxfs_immed.c

     /*
      * Copyright (c) 2000-2001 Christoph Hellwig.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions, and the following disclaimer,
     *    without modification.
     * 2. The name of the author may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     *
     * Alternatively, this software may be distributed under the terms of the
     * GNU General Public License ("GPL").
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
     * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #ident "$Id: vxfs_immed.c,v 1.10 2001/04/25 18:11:23 hch Exp hch $"
    
    /*
     * Veritas filesystem driver - support for 'immed' inodes.
     */
    #include <linux/fs.h>
    #include <linux/pagemap.h>
    
    #include "vxfs.h"
    #include "vxfs_inode.h"
    
    
    static int      vxfs_immed_readlink(struct dentry *, char *, int);
    static int      vxfs_immed_follow_link(struct dentry *, struct nameidata *);
    
    static int      vxfs_immed_readpage(struct file *, struct page *);
    
    /*
     * Inode operations for immed symlinks.
     *
     * Unliked all other operations we do not go through the pagecache,
     * but do all work directly on the inode.
     */
    struct inode_operations vxfs_immed_symlink_iops = {
            .readlink =             vxfs_immed_readlink,
            .follow_link =          vxfs_immed_follow_link,
    };
    
    /*
     * Adress space operations for immed files and directories.
     */
    struct address_space_operations vxfs_immed_aops = {
            .readpage =             vxfs_immed_readpage,
    };
    
    
    /**
     * vxfs_immed_readlink - read immed symlink
     * @dp:         dentry for the link
     * @bp:         output buffer
     * @buflen:     length of @bp
     *
     * Description:
     *   vxfs_immed_readlink calls vfs_readlink to read the link
     *   described by @dp into userspace.
     *
     * Returns:
     *   Number of bytes successfully copied to userspace.
     */
    static int
    vxfs_immed_readlink(struct dentry *dp, char *bp, int buflen)
    {
            struct vxfs_inode_info          *vip = VXFS_INO(dp->d_inode);
    
            return (vfs_readlink(dp, bp, buflen, vip->vii_immed.vi_immed));
    }
    
    /**
     * vxfs_immed_follow_link - follow immed symlink
     * @dp:         dentry for the link
     * @np:         pathname lookup data for the current path walk
     *
     * Description:
     *   vxfs_immed_follow_link restarts the pathname lookup with
     *   the data obtained from @dp.
     *
     * Returns:
     *   Zero on success, else a negative error code.
     */
    static int
   vxfs_immed_follow_link(struct dentry *dp, struct nameidata *np)
   {
           struct vxfs_inode_info          *vip = VXFS_INO(dp->d_inode);
   
           return (vfs_follow_link(np, vip->vii_immed.vi_immed));
   }
   
   /**
    * vxfs_immed_readpage - read part of an immed inode into pagecache
    * @file:       file context (unused)
    * @page:       page frame to fill in.
    *
    * Description:
    *   vxfs_immed_readpage reads a part of the immed area of the
    *   file that hosts @pp into the pagecache.
    *
    * Returns:
    *   Zero on success, else a negative error code.
    *
    * Locking status:
    *   @page is locked and will be unlocked.
    */
   static int
   vxfs_immed_readpage(struct file *fp, struct page *pp)
   {
           struct vxfs_inode_info  *vip = VXFS_INO(pp->mapping->host);
           u_int64_t               offset = pp->index << PAGE_CACHE_SHIFT;
           caddr_t                 kaddr;
   
           kaddr = kmap(pp);
           memcpy(kaddr, vip->vii_immed.vi_immed + offset, PAGE_CACHE_SIZE);
           kunmap(pp);
           
           flush_dcache_page(pp);
           SetPageUptodate(pp);
           UnlockPage(pp);
   
           return 0;
   }

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