e2fsprogs/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 #include <unistd.h>
  16 #include <string.h>
  17 #include <time.h>
  18
  19 #include "ext2_fs.h"
  20 #include "ext2_ext_attr.h"
  21 #include "ext2fs.h"
  22
  23 errcode_t ext2fs_read_ext_attr(ext2_filsys fs, blk_t block, void *buf)
  24 {
  25         errcode_t       retval;
  26
  27         retval = io_channel_read_blk(fs->io, block, 1, buf);
  28         if (retval)
  29                 return retval;
  30 #if BB_BIG_ENDIAN
  31         if ((fs->flags & (EXT2_FLAG_SWAP_BYTES|
  32                           EXT2_FLAG_SWAP_BYTES_READ)) != 0)
  33                 ext2fs_swap_ext_attr(buf, buf, fs->blocksize, 1);
  34 #endif
  35         return 0;
  36 }
  37
  38 errcode_t ext2fs_write_ext_attr(ext2_filsys fs, blk_t block, void *inbuf)
  39 {
  40         errcode_t       retval;
  41         char            *write_buf;
  42         char            *buf = NULL;
  43
  44 #if BB_BIG_ENDIAN
  45         if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
  46             (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) {
  47                 retval = ext2fs_get_mem(fs->blocksize, &buf);
  48                 if (retval)
  49                         return retval;
  50                 write_buf = buf;
  51                 ext2fs_swap_ext_attr(buf, inbuf, fs->blocksize, 1);
  52         } else
  53 #endif
  54                 write_buf = (char *) inbuf;
  55         retval = io_channel_write_blk(fs->io, block, 1, write_buf);
  56         if (buf)
  57                 ext2fs_free_mem(&buf);
  58         if (!retval)
  59                 ext2fs_mark_changed(fs);
  60         return retval;
  61 }
  62
  63 /*
  64  * This function adjusts the reference count of the EA block.
  65  */
  66 errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
  67                                     char *block_buf, int adjust,
  68                                     __u32 *newcount)
  69 {
  70         errcode_t       retval;
  71         struct ext2_ext_attr_header *header;
  72         char    *buf = 0;
  73
  74         if ((blk >= fs->super->s_blocks_count) ||
  75             (blk < fs->super->s_first_data_block))
  76                 return EXT2_ET_BAD_EA_BLOCK_NUM;
  77
  78         if (!block_buf) {
  79                 retval = ext2fs_get_mem(fs->blocksize, &buf);
  80                 if (retval)
  81                         return retval;
  82                 block_buf = buf;
  83         }
  84
  85         retval = ext2fs_read_ext_attr(fs, blk, block_buf);
  86         if (retval)
  87                 goto errout;
  88
  89         header = (struct ext2_ext_attr_header *) block_buf;
  90         header->h_refcount += adjust;
  91         if (newcount)
  92                 *newcount = header->h_refcount;
  93
  94         retval = ext2fs_write_ext_attr(fs, blk, block_buf);
  95         if (retval)
  96                 goto errout;
  97
  98 errout:
  99         if (buf)
 100                 ext2fs_free_mem(&buf);
 101         return retval;
 102 }