mkjournal.c revision 7a34cb01a97d39842c610dd609b525eadd0a1de2 
1/*
2 * mkjournal.c --- make a journal for a filesystem
3 *
4 * Copyright (C) 2000 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Public
8 * License.
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#if HAVE_ERRNO_H
18#include <errno.h>
19#endif
20#include <fcntl.h>
21#include <time.h>
22#if HAVE_SYS_STAT_H
23#include <sys/stat.h>
24#endif
25#if HAVE_SYS_TYPES_H
26#include <sys/types.h>
27#endif
28#if HAVE_NETINET_IN_H
29#include <netinet/in.h>
30#endif
31
32#if EXT2_FLAT_INCLUDES
33#include "ext2_fs.h"
34#else
35#include <linux/ext2_fs.h>
36#endif
37
38#include "e2p/e2p.h"
39#include "ext2fs.h"
40#include "jfs_user.h"
41
42/*
43 * This function automatically sets up the journal superblock and
44 * returns it as an allocated block.
45 */
46errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
47					   __u32 size, int flags,
48					   char  **ret_jsb)
49{
50	errcode_t		retval;
51	journal_superblock_t	*jsb;
52
53	if (size < 1024)
54		return EXT2_ET_JOURNAL_TOO_SMALL;
55
56	if ((retval = ext2fs_get_mem(fs->blocksize, (void **) &jsb)))
57		return retval;
58
59	memset (jsb, 0, fs->blocksize);
60
61	jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
62	if (flags & EXT2_MKJOURNAL_V1_SUPER)
63		jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V1);
64	else
65		jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
66	jsb->s_blocksize = htonl(fs->blocksize);
67	jsb->s_maxlen = htonl(size);
68	jsb->s_nr_users = htonl(1);
69	jsb->s_first = htonl(1);
70	jsb->s_sequence = htonl(1);
71	memcpy(jsb->s_uuid, fs->super->s_uuid, sizeof(fs->super->s_uuid));
72	/*
73	 * If we're creating an external journal device, we need to
74	 * adjust these fields.
75	 */
76	if (fs->super->s_feature_incompat &
77	    EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)
78		jsb->s_nr_users = 0;
79
80	*ret_jsb = (char *) jsb;
81	return 0;
82}
83
84/*
85 * This function writes a journal using POSIX routines.  It is used
86 * for creating external journals and creating journals on live
87 * filesystems.
88 */
89static errcode_t write_journal_file(ext2_filsys fs, char *filename,
90				    blk_t size, int flags)
91{
92	errcode_t	retval;
93	char		*buf = 0;
94	int		i, fd, ret_size;
95
96	if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
97		return retval;
98
99	/* Open the device or journal file */
100	if ((fd = open(filename, O_WRONLY)) < 0) {
101		retval = errno;
102		goto errout;
103	}
104
105	/* Write the superblock out */
106	retval = EXT2_ET_SHORT_WRITE;
107	ret_size = write(fd, buf, fs->blocksize);
108	if (ret_size < 0) {
109		retval = errno;
110		goto errout;
111	}
112	if (ret_size != fs->blocksize)
113		goto errout;
114	memset(buf, 0, fs->blocksize);
115
116	for (i = 1; i < size; i++) {
117		ret_size = write(fd, buf, fs->blocksize);
118		if (ret_size < 0) {
119			retval = errno;
120			goto errout;
121		}
122		if (ret_size != fs->blocksize)
123			goto errout;
124	}
125	close(fd);
126
127	retval = 0;
128errout:
129	ext2fs_free_mem((void **) &buf);
130	return retval;
131}
132
133/*
134 * Helper function for creating the journal using direct I/O routines
135 */
136struct mkjournal_struct {
137	int		num_blocks;
138	int		newblocks;
139	char		*buf;
140	errcode_t	err;
141};
142
143static int mkjournal_proc(ext2_filsys		fs,
144			   blk_t		*blocknr,
145			   e2_blkcnt_t		blockcnt,
146			   blk_t		ref_block,
147			   int			ref_offset,
148			   void			*priv_data)
149{
150	struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data;
151	blk_t	new_blk;
152	static blk_t	last_blk = 0;
153	errcode_t	retval;
154	int		group;
155
156	if (*blocknr) {
157		last_blk = *blocknr;
158		return 0;
159	}
160	retval = ext2fs_new_block(fs, last_blk, 0, &new_blk);
161	if (retval) {
162		es->err = retval;
163		return BLOCK_ABORT;
164	}
165	if (blockcnt > 0)
166		es->num_blocks--;
167
168	es->newblocks++;
169	retval = io_channel_write_blk(fs->io, new_blk, 1, es->buf);
170
171	if (blockcnt == 0)
172		memset(es->buf, 0, fs->blocksize);
173
174	if (retval) {
175		es->err = retval;
176		return BLOCK_ABORT;
177	}
178	*blocknr = new_blk;
179	ext2fs_mark_block_bitmap(fs->block_map, new_blk);
180	ext2fs_mark_bb_dirty(fs);
181	group = ext2fs_group_of_blk(fs, new_blk);
182	fs->group_desc[group].bg_free_blocks_count--;
183	fs->super->s_free_blocks_count--;
184	ext2fs_mark_super_dirty(fs);
185
186	if (es->num_blocks == 0)
187		return (BLOCK_CHANGED | BLOCK_ABORT);
188	else
189		return BLOCK_CHANGED;
190
191}
192
193/*
194 * This function creates a journal using direct I/O routines.
195 */
196static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
197				     blk_t size, int flags)
198{
199	char			*buf;
200	errcode_t		retval;
201	struct ext2_inode	inode;
202	struct mkjournal_struct	es;
203
204	if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
205		return retval;
206
207	if ((retval = ext2fs_read_bitmaps(fs)))
208		return retval;
209
210	if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
211		return retval;
212
213	if (inode.i_blocks > 0)
214		return EEXIST;
215
216	es.num_blocks = size;
217	es.newblocks = 0;
218	es.buf = buf;
219	es.err = 0;
220
221	retval = ext2fs_block_iterate2(fs, journal_ino, BLOCK_FLAG_APPEND,
222				       0, mkjournal_proc, &es);
223	if (es.err) {
224		retval = es.err;
225		goto errout;
226	}
227
228	if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
229		goto errout;
230
231 	inode.i_size += fs->blocksize * size;
232	inode.i_blocks += (fs->blocksize / 512) * es.newblocks;
233	inode.i_mtime = inode.i_ctime = time(0);
234	inode.i_links_count = 1;
235	inode.i_mode = LINUX_S_IFREG | 0600;
236
237	if ((retval = ext2fs_write_inode(fs, journal_ino, &inode)))
238		goto errout;
239	retval = 0;
240
241errout:
242	ext2fs_free_mem((void **) &buf);
243	return retval;
244}
245
246/*
247 * This function adds a journal device to a filesystem
248 */
249errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
250{
251	struct stat	st;
252	errcode_t	retval;
253	char		buf[1024];
254	journal_superblock_t	*jsb;
255	int		i;
256	__u32		nr_users;
257
258	/* Make sure the device exists and is a block device */
259	if (stat(journal_dev->device_name, &st) < 0)
260		return errno;
261
262	if (!S_ISBLK(st.st_mode))
263		return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
264
265	/* Get the journal superblock */
266	if ((retval = io_channel_read_blk(journal_dev->io, 1, -1024, buf)))
267		return retval;
268
269	jsb = (journal_superblock_t *) buf;
270	if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
271	    (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
272		return EXT2_ET_NO_JOURNAL_SB;
273
274	if (ntohl(jsb->s_blocksize) != fs->blocksize)
275		return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
276
277	/* Check and see if this filesystem has already been added */
278	nr_users = ntohl(jsb->s_nr_users);
279	for (i=0; i < nr_users; i++) {
280		if (memcmp(fs->super->s_uuid,
281			   &jsb->s_users[i*16], 16) == 0)
282			break;
283	}
284	if (i >= nr_users) {
285		memcpy(&jsb->s_users[nr_users*16],
286		       fs->super->s_uuid, 16);
287		jsb->s_nr_users = htonl(nr_users+1);
288	}
289
290	/* Writeback the journal superblock */
291	if ((retval = io_channel_write_blk(journal_dev->io, 1, -1024, buf)))
292		return retval;
293
294	fs->super->s_journal_inum = 0;
295	fs->super->s_journal_dev = st.st_rdev;
296	memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
297	       sizeof(fs->super->s_journal_uuid));
298	fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
299	ext2fs_mark_super_dirty(fs);
300	return 0;
301}
302
303/*
304 * This function adds a journal inode to a filesystem, using either
305 * POSIX routines if the filesystem is mounted, or using direct I/O
306 * functions if it is not.
307 */
308errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t size, int flags)
309{
310	errcode_t		retval;
311	ext2_ino_t		journal_ino;
312	struct stat		st;
313	char			jfile[1024];
314	int			fd, mount_flags;
315
316	if ((retval = ext2fs_check_mount_point(fs->device_name, &mount_flags,
317					       jfile, sizeof(jfile)-10)))
318		return retval;
319
320	if (mount_flags & EXT2_MF_MOUNTED) {
321		strcat(jfile, "/.journal");
322
323		/* Create the journal file */
324		if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
325			return errno;
326		close(fd);
327
328		if ((retval = write_journal_file(fs, jfile, size, flags)))
329			return retval;
330
331		/* Get inode number of the journal file */
332		if (stat(jfile, &st) < 0)
333			return errno;
334
335		if ((retval = fsetflags(jfile,
336					EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL)))
337			return retval;
338
339		journal_ino = st.st_ino;
340	} else {
341		journal_ino = EXT2_JOURNAL_INO;
342		if ((retval = write_journal_inode(fs, journal_ino,
343						  size, flags)))
344			return retval;
345	}
346
347	fs->super->s_journal_inum = journal_ino;
348	fs->super->s_journal_dev = 0;
349	memset(fs->super->s_journal_uuid, 0,
350	       sizeof(fs->super->s_journal_uuid));
351	fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
352
353	ext2fs_mark_super_dirty(fs);
354	return 0;
355}
356
357#ifdef DEBUG
358main(int argc, char **argv)
359{
360	errcode_t	retval;
361	char		*device_name;
362	ext2_filsys 	fs;
363
364	if (argc < 2) {
365		fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
366		exit(1);
367	}
368	device_name = argv[1];
369
370	retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
371			      unix_io_manager, &fs);
372	if (retval) {
373		com_err(argv[0], retval, "while opening %s", device_name);
374		exit(1);
375	}
376
377	retval = ext2fs_add_journal_inode(fs, 1024);
378	if (retval) {
379		com_err(argv[0], retval, "while adding journal to %s",
380			device_name);
381		exit(1);
382	}
383	retval = ext2fs_flush(fs);
384	if (retval) {
385		printf("Warning, had trouble writing out superblocks.\n");
386	}
387	ext2fs_close(fs);
388	exit(0);
389
390}
391#endif
392