rw_bitmaps.c revision e48bf256e99e4923c6193ff78000af18c700d93d 
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 > (int) fs->blocksize) ||
167	    (inode_nbytes > (int) fs->blocksize))
168		return EXT2_ET_CORRUPT_SUPERBLOCK;
169
170	fs->write_bitmaps = ext2fs_write_bitmaps;
171
172	if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
173				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
174		csum_flag = 1;
175
176	retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
177	if (retval)
178		return retval;
179	if (do_block) {
180		if (fs->block_map)
181			ext2fs_free_block_bitmap(fs->block_map);
182		strcpy(buf, "block bitmap for ");
183		strcat(buf, fs->device_name);
184		retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
185		if (retval)
186			goto cleanup;
187		retval = io_channel_alloc_buf(fs->io, 0, &block_bitmap);
188		if (retval)
189			goto cleanup;
190	} else
191		block_nbytes = 0;
192	if (do_inode) {
193		if (fs->inode_map)
194			ext2fs_free_inode_bitmap(fs->inode_map);
195		strcpy(buf, "inode bitmap for ");
196		strcat(buf, fs->device_name);
197		retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
198		if (retval)
199			goto cleanup;
200		retval = io_channel_alloc_buf(fs->io, 0, &inode_bitmap);
201		if (retval)
202			goto cleanup;
203	} else
204		inode_nbytes = 0;
205	ext2fs_free_mem(&buf);
206
207	if (fs->flags & EXT2_FLAG_IMAGE_FILE) {
208		blk = (fs->image_header->offset_inodemap / fs->blocksize);
209		ino_cnt = fs->super->s_inodes_count;
210		while (inode_nbytes > 0) {
211			retval = io_channel_read_blk64(fs->image_io, blk++,
212						     1, inode_bitmap);
213			if (retval)
214				goto cleanup;
215			cnt = fs->blocksize << 3;
216			if (cnt > ino_cnt)
217				cnt = ino_cnt;
218			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
219					       ino_itr, cnt, inode_bitmap);
220			if (retval)
221				goto cleanup;
222			ino_itr += fs->blocksize << 3;
223			ino_cnt -= fs->blocksize << 3;
224			inode_nbytes -= fs->blocksize;
225		}
226		blk = (fs->image_header->offset_blockmap /
227		       fs->blocksize);
228		blk_cnt = (blk64_t)EXT2_CLUSTERS_PER_GROUP(fs->super) *
229			fs->group_desc_count;
230		while (block_nbytes > 0) {
231			retval = io_channel_read_blk64(fs->image_io, blk++,
232						     1, block_bitmap);
233			if (retval)
234				goto cleanup;
235			cnt = fs->blocksize << 3;
236			if (cnt > blk_cnt)
237				cnt = blk_cnt;
238			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
239				       blk_itr, cnt, block_bitmap);
240			if (retval)
241				goto cleanup;
242			blk_itr += fs->blocksize << 3;
243			blk_cnt -= fs->blocksize << 3;
244			block_nbytes -= fs->blocksize;
245		}
246		goto success_cleanup;
247	}
248
249	for (i = 0; i < fs->group_desc_count; i++) {
250		if (block_bitmap) {
251			blk = ext2fs_block_bitmap_loc(fs, i);
252			if (csum_flag &&
253			    ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT) &&
254			    ext2fs_group_desc_csum_verify(fs, i))
255				blk = 0;
256			if (blk) {
257				retval = io_channel_read_blk64(fs->io, blk,
258							       1, block_bitmap);
259				if (retval) {
260					retval = EXT2_ET_BLOCK_BITMAP_READ;
261					goto cleanup;
262				}
263			} else
264				memset(block_bitmap, 0, block_nbytes);
265			cnt = block_nbytes << 3;
266			retval = ext2fs_set_block_bitmap_range2(fs->block_map,
267					       blk_itr, cnt, block_bitmap);
268			if (retval)
269				goto cleanup;
270			blk_itr += block_nbytes << 3;
271		}
272		if (inode_bitmap) {
273			blk = ext2fs_inode_bitmap_loc(fs, i);
274			if (csum_flag &&
275			    ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT) &&
276			    ext2fs_group_desc_csum_verify(fs, i))
277				blk = 0;
278			if (blk) {
279				retval = io_channel_read_blk64(fs->io, blk,
280							       1, inode_bitmap);
281				if (retval) {
282					retval = EXT2_ET_INODE_BITMAP_READ;
283					goto cleanup;
284				}
285			} else
286				memset(inode_bitmap, 0, inode_nbytes);
287			cnt = inode_nbytes << 3;
288			retval = ext2fs_set_inode_bitmap_range2(fs->inode_map,
289					       ino_itr, cnt, inode_bitmap);
290			if (retval)
291				goto cleanup;
292			ino_itr += inode_nbytes << 3;
293		}
294	}
295success_cleanup:
296	if (inode_bitmap)
297		ext2fs_free_mem(&inode_bitmap);
298	if (block_bitmap)
299		ext2fs_free_mem(&block_bitmap);
300	return 0;
301
302cleanup:
303	if (do_block) {
304		ext2fs_free_mem(&fs->block_map);
305		fs->block_map = 0;
306	}
307	if (do_inode) {
308		ext2fs_free_mem(&fs->inode_map);
309		fs->inode_map = 0;
310	}
311	if (inode_bitmap)
312		ext2fs_free_mem(&inode_bitmap);
313	if (block_bitmap)
314		ext2fs_free_mem(&block_bitmap);
315	if (buf)
316		ext2fs_free_mem(&buf);
317	return retval;
318}
319
320errcode_t ext2fs_read_inode_bitmap(ext2_filsys fs)
321{
322	return read_bitmaps(fs, 1, 0);
323}
324
325errcode_t ext2fs_read_block_bitmap(ext2_filsys fs)
326{
327	return read_bitmaps(fs, 0, 1);
328}
329
330errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs)
331{
332	return write_bitmaps(fs, 1, 0);
333}
334
335errcode_t ext2fs_write_block_bitmap (ext2_filsys fs)
336{
337	return write_bitmaps(fs, 0, 1);
338}
339
340errcode_t ext2fs_read_bitmaps(ext2_filsys fs)
341{
342	if (fs->inode_map && fs->block_map)
343		return 0;
344
345	return read_bitmaps(fs, !fs->inode_map, !fs->block_map);
346}
347
348errcode_t ext2fs_write_bitmaps(ext2_filsys fs)
349{
350	int do_inode = fs->inode_map && ext2fs_test_ib_dirty(fs);
351	int do_block = fs->block_map && ext2fs_test_bb_dirty(fs);
352
353	if (!do_inode && !do_block)
354		return 0;
355
356	return write_bitmaps(fs, do_inode, do_block);
357}
358