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1 /*
2  * i_block.c --- Manage the i_block field for i_blocks
3  *
4  * Copyright (C) 2008 Theodore Ts'o.
5  *
6  * %Begin-Header%
7  * This file may be redistributed under the terms of the GNU Library
8  * General Public License, version 2.
9  * %End-Header%
10  */
11 
12 #include <stdio.h>
13 #if HAVE_UNISTD_H
14 #include <unistd.h>
15 #endif
16 #include <time.h>
17 #include <string.h>
18 #if HAVE_SYS_STAT_H
19 #include <sys/stat.h>
20 #endif
21 #if HAVE_SYS_TYPES_H
22 #include <sys/types.h>
23 #endif
24 #include <errno.h>
25 
26 #include "ext2_fs.h"
27 #include "ext2fs.h"
28 
ext2fs_iblk_add_blocks(ext2_filsys fs,struct ext2_inode * inode,blk64_t num_blocks)29 errcode_t ext2fs_iblk_add_blocks(ext2_filsys fs, struct ext2_inode *inode,
30 				 blk64_t num_blocks)
31 {
32 	unsigned long long b = inode->i_blocks;
33 
34 	if (!(fs->super->s_feature_ro_compat &
35 	      EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
36 	    !(inode->i_flags & EXT4_HUGE_FILE_FL))
37 	    num_blocks *= fs->blocksize / 512;
38 
39 	b += num_blocks;
40 
41 	if (fs->super->s_feature_ro_compat &
42 	    EXT4_FEATURE_RO_COMPAT_HUGE_FILE) {
43 		b += ((long long) inode->osd2.linux2.l_i_blocks_hi) << 32;
44 		inode->osd2.linux2.l_i_blocks_hi = b >> 32;
45 	} else if (b > 0xFFFFFFFF)
46 		return EOVERFLOW;
47 	inode->i_blocks = b & 0xFFFFFFFF;
48 	return 0;
49 }
50 
ext2fs_iblk_sub_blocks(ext2_filsys fs,struct ext2_inode * inode,blk64_t num_blocks)51 errcode_t ext2fs_iblk_sub_blocks(ext2_filsys fs, struct ext2_inode *inode,
52 				 blk64_t num_blocks)
53 {
54 	unsigned long long b = inode->i_blocks;
55 
56 	if (!(fs->super->s_feature_ro_compat &
57 	      EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
58 	    !(inode->i_flags & EXT4_HUGE_FILE_FL))
59 	    num_blocks *= fs->blocksize / 512;
60 
61 	if (num_blocks > b)
62 		return EOVERFLOW;
63 
64 	b -= num_blocks;
65 
66 	if (fs->super->s_feature_ro_compat &
67 	    EXT4_FEATURE_RO_COMPAT_HUGE_FILE) {
68 		b += ((long long) inode->osd2.linux2.l_i_blocks_hi) << 32;
69 		inode->osd2.linux2.l_i_blocks_hi = b >> 32;
70 	}
71 	inode->i_blocks = b & 0xFFFFFFFF;
72 	return 0;
73 }
74 
ext2fs_iblk_set(ext2_filsys fs,struct ext2_inode * inode,blk64_t b)75 errcode_t ext2fs_iblk_set(ext2_filsys fs, struct ext2_inode *inode, blk64_t b)
76 {
77 	if (!(fs->super->s_feature_ro_compat &
78 	      EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
79 	    !(inode->i_flags & EXT4_HUGE_FILE_FL))
80 		b *= fs->blocksize / 512;
81 
82 	inode->i_blocks = b & 0xFFFFFFFF;
83 	if (fs->super->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_HUGE_FILE)
84 		inode->osd2.linux2.l_i_blocks_hi = b >> 32;
85 	else if (b >> 32)
86 		return EOVERFLOW;
87 	return 0;
88 }
89