rw_bitmaps.c revision e0ed7404719a9ddd2ba427a80db5365c8bad18c0 
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 <stdio.h>
13#include <string.h>
14#if HAVE_UNISTD_H
15#include <unistd.h>
16#endif
17#include <fcntl.h>
18#include <time.h>
19#ifdef HAVE_SYS_STAT_H
20#include <sys/stat.h>
21#endif
22#ifdef HAVE_SYS_TYPES_H
23#include <sys/types.h>
24#endif
25
26#include "ext2_fs.h"
27#include "ext2fs.h"
28#include "e2image.h"
29
30static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
31{
32	dgrp_t 		i;
33	unsigned int	j;
34	int		block_nbytes, inode_nbytes;
35	unsigned int	nbits;
36	errcode_t	retval;
37	char		*block_buf = NULL, *inode_buf = NULL;
38	int		csum_flag = 0;
39	blk64_t		blk;
40	blk64_t		blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
41	ext2_ino_t	ino_itr = 1;
42
43	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
44
45	if (!(fs->flags & EXT2_FLAG_RW))
46		return EXT2_ET_RO_FILSYS;
47
48	if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
49				       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
50		csum_flag = 1;
51
52	inode_nbytes = block_nbytes = 0;
53	if (do_block) {
54		block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
55		retval = io_channel_alloc_buf(fs->io, 0, &block_buf);
56		if (retval)
57			goto errout;
58		memset(block_buf, 0xff, fs->blocksize);
59	}
60	if (do_inode) {
61		inode_nbytes = (size_t)
62			((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
63		retval = io_channel_alloc_buf(fs->io, 0, &inode_buf);
64		if (retval)
65			goto errout;
66		memset(inode_buf, 0xff, fs->blocksize);
67	}
68
69	for (i = 0; i < fs->group_desc_count; i++) {
70		if (!do_block)
71			goto skip_block_bitmap;
72
73		if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_BLOCK_UNINIT)
74		    )
75			goto skip_this_block_bitmap;
76
77		retval = ext2fs_get_block_bitmap_range2(fs->block_map,
78				blk_itr, block_nbytes << 3, block_buf);
79		if (retval)
80			goto errout;
81
82		if (i == fs->group_desc_count - 1) {
83			/* Force bitmap padding for the last group */
84			nbits = EXT2FS_NUM_B2C(fs,
85				((ext2fs_blocks_count(fs->super)
86				  - (__u64) fs->super->s_first_data_block)
87				 % (__u64) EXT2_BLOCKS_PER_GROUP(fs->super)));
88			if (nbits)
89				for (j = nbits; j < fs->blocksize * 8; j++)
90					ext2fs_set_bit(j, block_buf);
91		}
92		blk = ext2fs_block_bitmap_loc(fs, i);
93		if (blk) {
94			retval = io_channel_write_blk64(fs->io, blk, 1,
95							block_buf);
96			if (retval) {
97				retval = EXT2_ET_BLOCK_BITMAP_WRITE;
98				goto errout;
99			}
100		}
101	skip_this_block_bitmap:
102		blk_itr += block_nbytes << 3;
103	skip_block_bitmap:
104
105		if (!do_inode)
106			continue;
107
108		if (csum_flag && ext2fs_bg_flags_test(fs, i, EXT2_BG_INODE_UNINIT)
109		    )
110			goto skip_this_inode_bitmap;
111
112		retval = ext2fs_get_inode_bitmap_range2(fs->inode_map,
113				ino_itr, inode_nbytes << 3, inode_buf);
114		if (retval)
115			goto errout;
116
117		blk = ext2fs_inode_bitmap_loc(fs, i);
118		if (blk) {
119			retval = io_channel_write_blk64(fs->io, blk, 1,
120						      inode_buf);
121			if (retval) {
122				retval = EXT2_ET_INODE_BITMAP_WRITE;
123				goto errout;
124			}
125		}
126	skip_this_inode_bitmap:
127		ino_itr += inode_nbytes << 3;
128
129	}
130	if (do_block) {
131		fs->flags &= ~EXT2_FLAG_BB_DIRTY;
132		ext2fs_free_mem(&block_buf);
133	}
134	if (do_inode) {
135		fs->flags &= ~EXT2_FLAG_IB_DIRTY;
136		ext2fs_free_mem(&inode_buf);
137	}
138	return 0;
139errout:
140	if (inode_buf)
141		ext2fs_free_mem(&inode_buf);
142	if (block_buf)
143		ext2fs_free_mem(&block_buf);
144	return retval;
145}
146
147static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
148{
149	dgrp_t i;
150	char *block_bitmap = 0, *inode_bitmap = 0;
151	char *buf;
152	errcode_t retval;
153	int block_nbytes = EXT2_CLUSTERS_PER_GROUP(fs->super) / 8;
154	int inode_nbytes = EXT2_INODES_PER_GROUP(fs->super) / 8;
155	int csum_flag = 0;
156	unsigned int	cnt;
157	blk64_t	blk;
158	blk64_t	blk_itr = EXT2FS_B2C(fs, fs->super->s_first_data_block);
159	blk64_t   blk_cnt;
160	ext2_ino_t ino_itr = 1;
161	ext2_ino_t ino_cnt;
162
163	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
164
165	if ((block_nbytes > (int) fs->blocksize) ||
166	    (inode_nbytes > (int) 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