lib/ext2fs/ext_attr.c

   1 /*
   2  * ext_attr.c --- extended attribute blocks
   3  *
   4  * Copyright (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
   5  *
   6  * Copyright (C) 2002 Theodore Ts'o.
   7  *
   8  * %Begin-Header%
   9  * This file may be redistributed under the terms of the GNU Public
  10  * License.
  11  * %End-Header%
  12  */
  13
  14 #include <stdio.h>
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #include <string.h>
  19 #include <time.h>
  20
  21 #include "ext2_fs.h"
  22 #include "ext2_ext_attr.h"
  23
  24 #include "ext2fs.h"
  25
  26 errcode_t ext2fs_read_ext_attr(ext2_filsys fs, blk_t block, void *buf)
  27 {
  28         errcode_t       retval;
  29
  30         retval = io_channel_read_blk(fs->io, block, 1, buf);
  31         if (retval)
  32                 return retval;
  33 #ifdef EXT2FS_ENABLE_SWAPFS
  34         if ((fs->flags & (EXT2_FLAG_SWAP_BYTES|
  35                           EXT2_FLAG_SWAP_BYTES_READ)) != 0)
  36                 ext2fs_swap_ext_attr(buf, buf, fs->blocksize, 1);
  37 #endif
  38         return 0;
  39 }
  40
  41 errcode_t ext2fs_write_ext_attr(ext2_filsys fs, blk_t block, void *inbuf)
  42 {
  43         errcode_t       retval;
  44         char            *write_buf;
  45         char            *buf = NULL;
  46
  47 #ifdef EXT2FS_ENABLE_SWAPFS
  48         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
  49             (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) {
  50                 retval = ext2fs_get_mem(fs->blocksize, &buf);
  51                 if (retval)
  52                         return retval;
  53                 write_buf = buf;
  54                 ext2fs_swap_ext_attr(buf, inbuf, fs->blocksize, 1);
  55         } else
  56 #endif
  57                 write_buf = (char *) inbuf;
  58         retval = io_channel_write_blk(fs->io, block, 1, write_buf);
  59         if (buf)
  60                 ext2fs_free_mem(&buf);
  61         if (!retval)
  62                 ext2fs_mark_changed(fs);
  63         return retval;
  64 }
  65
  66 /*
  67  * This function adjusts the reference count of the EA block.
  68  */
  69 errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
  70                                     char *block_buf, int adjust,
  71                                     __u32 *newcount)
  72 {
  73         errcode_t       retval;
  74         struct ext2_ext_attr_header *header;
  75         char    *buf = 0;
  76
  77         if ((blk >= fs->super->s_blocks_count) ||
  78             (blk < fs->super->s_first_data_block))
  79                 return EXT2_ET_BAD_EA_BLOCK_NUM;
  80
  81         if (!block_buf) {
  82                 retval = ext2fs_get_mem(fs->blocksize, &buf);
  83                 if (retval)
  84                         return retval;
  85                 block_buf = buf;
  86         }
  87
  88         retval = ext2fs_read_ext_attr(fs, blk, block_buf);
  89         if (retval)
  90                 goto errout;
  91
  92         header = (struct ext2_ext_attr_header *) block_buf;
  93         header->h_refcount += adjust;
  94         if (newcount)
  95                 *newcount = header->h_refcount;
  96
  97         retval = ext2fs_write_ext_attr(fs, blk, block_buf);
  98         if (retval)
  99                 goto errout;
 100
 101 errout:
 102         if (buf)
 103                 ext2fs_free_mem(&buf);
 104         return retval;
 105 }