mkjournal.c revision 8bd0c95908baa3af706b9e731daff9472bec74c9 
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_SYS_IOCTL_H
29#include <sys/ioctl.h>
30#endif
31#if HAVE_NETINET_IN_H
32#include <netinet/in.h>
33#endif
34
35#include "ext2_fs.h"
36#include "e2p/e2p.h"
37#include "ext2fs.h"
38#include "jfs_user.h"
39
40/*
41 * This function automatically sets up the journal superblock and
42 * returns it as an allocated block.
43 */
44errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
45					   __u32 size, int flags,
46					   char  **ret_jsb)
47{
48	errcode_t		retval;
49	journal_superblock_t	*jsb;
50
51	if (size < 1024)
52		return EXT2_ET_JOURNAL_TOO_SMALL;
53
54	if ((retval = ext2fs_get_mem(fs->blocksize, (void **) &jsb)))
55		return retval;
56
57	memset (jsb, 0, fs->blocksize);
58
59	jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
60	if (flags & EXT2_MKJOURNAL_V1_SUPER)
61		jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V1);
62	else
63		jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
64	jsb->s_blocksize = htonl(fs->blocksize);
65	jsb->s_maxlen = htonl(size);
66	jsb->s_nr_users = htonl(1);
67	jsb->s_first = htonl(1);
68	jsb->s_sequence = htonl(1);
69	memcpy(jsb->s_uuid, fs->super->s_uuid, sizeof(fs->super->s_uuid));
70	/*
71	 * If we're creating an external journal device, we need to
72	 * adjust these fields.
73	 */
74	if (fs->super->s_feature_incompat &
75	    EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
76		jsb->s_nr_users = 0;
77		if (fs->blocksize == 1024)
78			jsb->s_first = htonl(3);
79		else
80			jsb->s_first = htonl(2);
81	}
82
83	*ret_jsb = (char *) jsb;
84	return 0;
85}
86
87/*
88 * This function writes a journal using POSIX routines.  It is used
89 * for creating external journals and creating journals on live
90 * filesystems.
91 */
92static errcode_t write_journal_file(ext2_filsys fs, char *filename,
93				    blk_t size, int flags)
94{
95	errcode_t	retval;
96	char		*buf = 0;
97	int		i, fd, ret_size;
98
99	if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
100		return retval;
101
102	/* Open the device or journal file */
103	if ((fd = open(filename, O_WRONLY)) < 0) {
104		retval = errno;
105		goto errout;
106	}
107
108	/* Write the superblock out */
109	retval = EXT2_ET_SHORT_WRITE;
110	ret_size = write(fd, buf, fs->blocksize);
111	if (ret_size < 0) {
112		retval = errno;
113		goto errout;
114	}
115	if (ret_size != fs->blocksize)
116		goto errout;
117	memset(buf, 0, fs->blocksize);
118
119	for (i = 1; i < size; i++) {
120		ret_size = write(fd, buf, fs->blocksize);
121		if (ret_size < 0) {
122			retval = errno;
123			goto errout;
124		}
125		if (ret_size != fs->blocksize)
126			goto errout;
127	}
128	close(fd);
129
130	retval = 0;
131errout:
132	ext2fs_free_mem((void **) &buf);
133	return retval;
134}
135
136/*
137 * Helper function for creating the journal using direct I/O routines
138 */
139struct mkjournal_struct {
140	int		num_blocks;
141	int		newblocks;
142	char		*buf;
143	errcode_t	err;
144};
145
146static int mkjournal_proc(ext2_filsys		fs,
147			   blk_t		*blocknr,
148			   e2_blkcnt_t		blockcnt,
149			   blk_t		ref_block,
150			   int			ref_offset,
151			   void			*priv_data)
152{
153	struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data;
154	blk_t	new_blk;
155	static blk_t	last_blk = 0;
156	errcode_t	retval;
157
158	if (*blocknr) {
159		last_blk = *blocknr;
160		return 0;
161	}
162	retval = ext2fs_new_block(fs, last_blk, 0, &new_blk);
163	if (retval) {
164		es->err = retval;
165		return BLOCK_ABORT;
166	}
167	if (blockcnt > 0)
168		es->num_blocks--;
169
170	es->newblocks++;
171	retval = io_channel_write_blk(fs->io, new_blk, 1, es->buf);
172
173	if (blockcnt == 0)
174		memset(es->buf, 0, fs->blocksize);
175
176	if (retval) {
177		es->err = retval;
178		return BLOCK_ABORT;
179	}
180	*blocknr = new_blk;
181	last_blk = new_blk;
182	ext2fs_block_alloc_stats(fs, new_blk, +1);
183
184	if (es->num_blocks == 0)
185		return (BLOCK_CHANGED | BLOCK_ABORT);
186	else
187		return BLOCK_CHANGED;
188
189}
190
191/*
192 * This function creates a journal using direct I/O routines.
193 */
194static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
195				     blk_t size, int flags)
196{
197	char			*buf;
198	errcode_t		retval;
199	struct ext2_inode	inode;
200	struct mkjournal_struct	es;
201
202	if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
203		return retval;
204
205	if ((retval = ext2fs_read_bitmaps(fs)))
206		return retval;
207
208	if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
209		return retval;
210
211	if (inode.i_blocks > 0)
212		return EEXIST;
213
214	es.num_blocks = size;
215	es.newblocks = 0;
216	es.buf = buf;
217	es.err = 0;
218
219	retval = ext2fs_block_iterate2(fs, journal_ino, BLOCK_FLAG_APPEND,
220				       0, mkjournal_proc, &es);
221	if (es.err) {
222		retval = es.err;
223		goto errout;
224	}
225
226	if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
227		goto errout;
228
229 	inode.i_size += fs->blocksize * size;
230	inode.i_blocks += (fs->blocksize / 512) * es.newblocks;
231	inode.i_mtime = inode.i_ctime = time(0);
232	inode.i_links_count = 1;
233	inode.i_mode = LINUX_S_IFREG | 0600;
234
235	if ((retval = ext2fs_write_inode(fs, journal_ino, &inode)))
236		goto errout;
237	retval = 0;
238
239errout:
240	ext2fs_free_mem((void **) &buf);
241	return retval;
242}
243
244/*
245 * This function adds a journal device to a filesystem
246 */
247errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
248{
249	struct stat	st;
250	errcode_t	retval;
251	char		buf[1024];
252	journal_superblock_t	*jsb;
253	int		i, start;
254	__u32		nr_users;
255
256	/* Make sure the device exists and is a block device */
257	if (stat(journal_dev->device_name, &st) < 0)
258		return errno;
259
260	if (!S_ISBLK(st.st_mode))
261		return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
262
263	/* Get the journal superblock */
264	start = 1;
265	if (journal_dev->blocksize == 1024)
266		start++;
267	if ((retval = io_channel_read_blk(journal_dev->io, start, -1024, buf)))
268		return retval;
269
270	jsb = (journal_superblock_t *) buf;
271	if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
272	    (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
273		return EXT2_ET_NO_JOURNAL_SB;
274
275	if (ntohl(jsb->s_blocksize) != fs->blocksize)
276		return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
277
278	/* Check and see if this filesystem has already been added */
279	nr_users = ntohl(jsb->s_nr_users);
280	for (i=0; i < nr_users; i++) {
281		if (memcmp(fs->super->s_uuid,
282			   &jsb->s_users[i*16], 16) == 0)
283			break;
284	}
285	if (i >= nr_users) {
286		memcpy(&jsb->s_users[nr_users*16],
287		       fs->super->s_uuid, 16);
288		jsb->s_nr_users = htonl(nr_users+1);
289	}
290
291	/* Writeback the journal superblock */
292	if ((retval = io_channel_write_blk(journal_dev->io, start, -1024, buf)))
293		return retval;
294
295	fs->super->s_journal_inum = 0;
296	fs->super->s_journal_dev = st.st_rdev;
297	memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
298	       sizeof(fs->super->s_journal_uuid));
299	fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
300	ext2fs_mark_super_dirty(fs);
301	return 0;
302}
303
304/*
305 * This function adds a journal inode to a filesystem, using either
306 * POSIX routines if the filesystem is mounted, or using direct I/O
307 * functions if it is not.
308 */
309errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t size, int flags)
310{
311	errcode_t		retval;
312	ext2_ino_t		journal_ino;
313	struct stat		st;
314	char			jfile[1024];
315	int			fd, mount_flags, f;
316
317	if ((retval = ext2fs_check_mount_point(fs->device_name, &mount_flags,
318					       jfile, sizeof(jfile)-10)))
319		return retval;
320
321	if (mount_flags & EXT2_MF_MOUNTED) {
322		strcat(jfile, "/.journal");
323
324		/*
325		 * If .../.journal already exists, make sure any
326		 * immutable or append-only flags are cleared.
327		 */
328#if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
329		(void) chflags (jfile, 0);
330#else
331#if HAVE_EXT2_IOCTLS
332		fd = open(jfile, O_RDONLY);
333		if (fd >= 0) {
334			f = 0;
335			ioctl(fd, EXT2_IOC_SETFLAGS, &f);
336			close(fd);
337		}
338#endif
339#endif
340
341		/* Create the journal file */
342		if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
343			return errno;
344
345		if ((retval = write_journal_file(fs, jfile, size, flags)))
346			goto errout;
347
348		/* Get inode number of the journal file */
349		if (fstat(fd, &st) < 0)
350			goto errout;
351
352#if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
353		retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
354#else
355#if HAVE_EXT2_IOCTLS
356		f = EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;
357		retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
358#endif
359#endif
360		if (retval)
361			goto errout;
362
363		close(fd);
364		journal_ino = st.st_ino;
365	} else {
366		journal_ino = EXT2_JOURNAL_INO;
367		if ((retval = write_journal_inode(fs, journal_ino,
368						  size, flags)))
369			return retval;
370	}
371
372	fs->super->s_journal_inum = journal_ino;
373	fs->super->s_journal_dev = 0;
374	memset(fs->super->s_journal_uuid, 0,
375	       sizeof(fs->super->s_journal_uuid));
376	fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
377
378	ext2fs_mark_super_dirty(fs);
379	return 0;
380errout:
381	close(fd);
382	return retval;
383}
384
385#ifdef DEBUG
386main(int argc, char **argv)
387{
388	errcode_t	retval;
389	char		*device_name;
390	ext2_filsys 	fs;
391
392	if (argc < 2) {
393		fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
394		exit(1);
395	}
396	device_name = argv[1];
397
398	retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
399			      unix_io_manager, &fs);
400	if (retval) {
401		com_err(argv[0], retval, "while opening %s", device_name);
402		exit(1);
403	}
404
405	retval = ext2fs_add_journal_inode(fs, 1024);
406	if (retval) {
407		com_err(argv[0], retval, "while adding journal to %s",
408			device_name);
409		exit(1);
410	}
411	retval = ext2fs_flush(fs);
412	if (retval) {
413		printf("Warning, had trouble writing out superblocks.\n");
414	}
415	ext2fs_close(fs);
416	exit(0);
417
418}
419#endif
420