rw_bitmaps.c revision 1d6fd6d0c3766a8165e69284c75812574a29c804 
1/*
2 * rw_bitmaps.c --- routines to read and write the  inode and block bitmaps.
3 *
4 * Copyright (C) 1993, 1994, 1994, 1996 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 "config.h"
13#include <stdio.h>
14#include <string.h>
15#if HAVE_UNISTD_H
16#include <unistd.h>
17#endif
18#include <fcntl.h>
19#include <time.h>
20#ifdef HAVE_SYS_STAT_H
21#include <sys/stat.h>
22#endif
23#ifdef HAVE_SYS_TYPES_H
24#include <sys/types.h>
25#endif
26
27#include "ext2_fs.h"
28#include "ext2fs.h"
29#include "e2image.h"
30
31static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
32{
33	dgrp_t 		i;
34	unsigned int	j;
35	int		block_nbytes, inode_nbytes;
36	unsigned int	nbits;
37	errcode_t	retval;
38	char		*block_buf = NULL, *inode_buf = NULL;
39	int		csum_flag = 0;
40	blk64_t		blk;
41	blk64_t		blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
42	ext2_ino_t	ino_itr = 1;
43
44	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
45
46	if (!(fs->flags & EXT2_FLAG_RW))
47		return EXT2_ET_RO_FILSYS;
48
49	if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
50				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
51		csum_flag = 1;
52
53	inode_nbytes = block_nbytes = 0;
54	if (do_block) {
55		block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
56		retval = io_channel_alloc_buf(fs->io, 0, &block_buf);
57		if (retval)
58			goto errout;
59		memset(block_buf, 0xff, fs->blocksize);
60	}
61	if (do_inode) {
62		inode_nbytes = (size_t)
63			((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
64		retval = io_channel_alloc_buf(fs->io, 0, &inode_buf);
65		if (retval)
66			goto errout;
67		memset(inode_buf, 0xff, fs->blocksize);
68	}
69
70	for (i = 0; i < fs->group_desc_count; i++) {
71		if (!do_block)
72			goto skip_block_bitmap;
73
74		if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT)
75		    )
76			goto skip_this_block_bitmap;
77
78		retval = ext2fs_get_block_bitmap_range2(fs->block_map,
79				blk_itr, block_nbytes << 3, block_buf);
80		if (retval)
81			goto errout;
82
83		if (i == fs->group_desc_count - 1) {
84			/* Force bitmap padding for the last group */
85			nbits = EXT2FS_NUM_B2C(fs,
86				((ext2fs_blocks_count(fs->super)
87				  - (__u64) fs->super->s_first_data_block)
88				 % (__u64) EXT2_BLOCKS_PER_GROUP(fs->super)));
89			if (nbits)
90				for (j = nbits; j < fs->blocksize * 8; j++)
91					ext2fs_set_bit(j, block_buf);
92		}
93		blk = ext2fs_block_bitmap_loc(fs, i);
94		if (blk) {
95			retval = io_channel_write_blk64(fs->io, blk, 1,
96							block_buf);
97			if (retval) {
98				retval = EXT2_ET_BLOCK_BITMAP_WRITE;
99				goto errout;
100			}
101		}
102	skip_this_block_bitmap:
103		blk_itr += block_nbytes << 3;
104	skip_block_bitmap:
105
106		if (!do_inode)
107			continue;
108
109		if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT)
110		    )
111			goto skip_this_inode_bitmap;
112
113		retval = ext2fs_get_inode_bitmap_range2(fs->inode_map,
114				ino_itr, inode_nbytes << 3, inode_buf);
115		if (retval)
116			goto errout;
117
118		blk = ext2fs_inode_bitmap_loc(fs, i);
119		if (blk) {
120			retval = io_channel_write_blk64(fs->io, blk, 1,
121						      inode_buf);
122			if (retval) {
123				retval = EXT2_ET_INODE_BITMAP_WRITE;
124				goto errout;
125			}
126		}
127	skip_this_inode_bitmap:
128		ino_itr += inode_nbytes << 3;
129
130	}
131	if (do_block) {
132		fs->flags &= ~EXT2_FLAG_BB_DIRTY;
133		ext2fs_free_mem(&block_buf);
134	}
135	if (do_inode) {
136		fs->flags &= ~EXT2_FLAG_IB_DIRTY;
137		ext2fs_free_mem(&inode_buf);
138	}
139	return 0;
140errout:
141	if (inode_buf)
142		ext2fs_free_mem(&inode_buf);
143	if (block_buf)
144		ext2fs_free_mem(&block_buf);
145	return retval;
146}
147
148static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
149{
150	dgrp_t i;
151	char *block_bitmap = 0, *inode_bitmap = 0;
152	char *buf;
153	errcode_t retval;
154	int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
155	int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
156	int csum_flag = 0;
157	unsigned int	cnt;
158	blk64_t	blk;
159	blk64_t	blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
160	blk64_t   blk_cnt;
161	ext2_ino_t ino_itr = 1;
162	ext2_ino_t ino_cnt;
163
164	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
165
166	if ((block_nbytes > fs->blocksize) || (inode_nbytes > fs->blocksize))
167		return EXT2_ET_CORRUPT_SUPERBLOCK;
168
169	fs->write_bitmaps = ext2fs_write_bitmaps;
170
171	if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
172				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
173		csum_flag = 1;
174
175	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
176	if (retval)
177		return retval;
178	if (do_block) {
179		if (fs->block_map)
180			ext2fs_free_block_bitmap(fs->block_map);
181		strcpy(buf, "block bitmap for ");
182		strcat(buf, fs->device_name);
183		retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
184		if (retval)
185			goto cleanup;
186		retval = io_channel_alloc_buf(fs->io, 0, &block_bitmap);
187		if (retval)
188			goto cleanup;
189	} else
190		block_nbytes = 0;
191	if (do_inode) {
192		if (fs->inode_map)
193			ext2fs_free_inode_bitmap(fs->inode_map);
194		strcpy(buf, "inode bitmap for ");
195		strcat(buf, fs->device_name);
196		retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
197		if (retval)
198			goto cleanup;
199		retval = io_channel_alloc_buf(fs->io, 0, &inode_bitmap);
200		if (retval)
201			goto cleanup;
202	} else
203		inode_nbytes = 0;
204	ext2fs_free_mem(&buf);
205
206	if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
207		blk = (fs->image_header->offset_inodemap / fs->blocksize);
208		ino_cnt = fs->super->s_inodes_count;
209		while (inode_nbytes > 0) {
210			retval = io_channel_read_blk64(fs->image_io, blk++,
211						     1, inode_bitmap);
212			if (retval)
213				goto cleanup;
214			cnt = fs->blocksize << 3;
215			if (cnt > ino_cnt)
216				cnt = ino_cnt;
217			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
218					       ino_itr, cnt, inode_bitmap);
219			if (retval)
220				goto cleanup;
221			ino_itr += fs->blocksize << 3;
222			ino_cnt -= fs->blocksize << 3;
223			inode_nbytes -= fs->blocksize;
224		}
225		blk = (fs->image_header->offset_blockmap /
226		       fs->blocksize);
227		blk_cnt = (blk64_t)EXT2_CLUSTERS_PER_GROUP(fs->super) *
228			fs->group_desc_count;
229		while (block_nbytes > 0) {
230			retval = io_channel_read_blk64(fs->image_io, blk++,
231						     1, block_bitmap);
232			if (retval)
233				goto cleanup;
234			cnt = fs->blocksize << 3;
235			if (cnt > blk_cnt)
236				cnt = blk_cnt;
237			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
238				       blk_itr, cnt, block_bitmap);
239			if (retval)
240				goto cleanup;
241			blk_itr += fs->blocksize << 3;
242			blk_cnt -= fs->blocksize << 3;
243			block_nbytes -= fs->blocksize;
244		}
245		goto success_cleanup;
246	}
247
248	for (i = 0; i < fs->group_desc_count; i++) {
249		if (block_bitmap) {
250			blk = ext2fs_block_bitmap_loc(fs, i);
251			if (csum_flag &&
252			    ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
253			    ext2fs_group_desc_csum_verify(fs, i))
254				blk = 0;
255			if (blk) {
256				retval = io_channel_read_blk64(fs->io, blk,
257							       1, block_bitmap);
258				if (retval) {
259					retval = EXT2_ET_BLOCK_BITMAP_READ;
260					goto cleanup;
261				}
262			} else
263				memset(block_bitmap, 0, block_nbytes);
264			cnt = block_nbytes << 3;
265			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
266					       blk_itr, cnt, block_bitmap);
267			if (retval)
268				goto cleanup;
269			blk_itr += block_nbytes << 3;
270		}
271		if (inode_bitmap) {
272			blk = ext2fs_inode_bitmap_loc(fs, i);
273			if (csum_flag &&
274			    ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
275			    ext2fs_group_desc_csum_verify(fs, i))
276				blk = 0;
277			if (blk) {
278				retval = io_channel_read_blk64(fs->io, blk,
279							       1, inode_bitmap);
280				if (retval) {
281					retval = EXT2_ET_INODE_BITMAP_READ;
282					goto cleanup;
283				}
284			} else
285				memset(inode_bitmap, 0, inode_nbytes);
286			cnt = inode_nbytes << 3;
287			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
288					       ino_itr, cnt, inode_bitmap);
289			if (retval)
290				goto cleanup;
291			ino_itr += inode_nbytes << 3;
292		}
293	}
294success_cleanup:
295	if (inode_bitmap)
296		ext2fs_free_mem(&inode_bitmap);
297	if (block_bitmap)
298		ext2fs_free_mem(&block_bitmap);
299	return 0;
300
301cleanup:
302	if (do_block) {
303		ext2fs_free_mem(&fs->block_map);
304		fs->block_map = 0;
305	}
306	if (do_inode) {
307		ext2fs_free_mem(&fs->inode_map);
308		fs->inode_map = 0;
309	}
310	if (inode_bitmap)
311		ext2fs_free_mem(&inode_bitmap);
312	if (block_bitmap)
313		ext2fs_free_mem(&block_bitmap);
314	if (buf)
315		ext2fs_free_mem(&buf);
316	return retval;
317}
318
319errcode_t ext2fs_read_inode_bitmap(ext2_filsys fs)
320{
321	return read_bitmaps(fs, 1, 0);
322}
323
324errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
325{
326	return read_bitmaps(fs, 0, 1);
327}
328
329errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
330{
331	return write_bitmaps(fs, 1, 0);
332}
333
334errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
335{
336	return write_bitmaps(fs, 0, 1);
337}
338
339errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
340{
341	if (fs->inode_map && fs->block_map)
342		return 0;
343
344	return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
345}
346
347errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
348{
349	int do_inode = fs->inode_map && ext2fs_test_ib_dirty(fs);
350	int do_block = fs->block_map && ext2fs_test_bb_dirty(fs);
351
352	if (!do_inode && !do_block)
353		return 0;
354
355	return write_bitmaps(fs, do_inode, do_block);
356}
357