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      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 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 #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  */
     44 errcode_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, &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  */
     92 static 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		fd, ret_size;
     98 	blk_t		i;
     99 
    100 	if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
    101 		return retval;
    102 
    103 	/* Open the device or journal file */
    104 	if ((fd = open(filename, O_WRONLY)) < 0) {
    105 		retval = errno;
    106 		goto errout;
    107 	}
    108 
    109 	/* Write the superblock out */
    110 	retval = EXT2_ET_SHORT_WRITE;
    111 	ret_size = write(fd, buf, fs->blocksize);
    112 	if (ret_size < 0) {
    113 		retval = errno;
    114 		goto errout;
    115 	}
    116 	if (ret_size != (int) fs->blocksize)
    117 		goto errout;
    118 	memset(buf, 0, fs->blocksize);
    119 
    120 	for (i = 1; i < size; i++) {
    121 		ret_size = write(fd, buf, fs->blocksize);
    122 		if (ret_size < 0) {
    123 			retval = errno;
    124 			goto errout;
    125 		}
    126 		if (ret_size != (int) fs->blocksize)
    127 			goto errout;
    128 	}
    129 	close(fd);
    130 
    131 	retval = 0;
    132 errout:
    133 	ext2fs_free_mem(&buf);
    134 	return retval;
    135 }
    136 
    137 /*
    138  * Convenience function which zeros out _num_ blocks starting at
    139  * _blk_.  In case of an error, the details of the error is returned
    140  * via _ret_blk_ and _ret_count_ if they are non-NULL pointers.
    141  * Returns 0 on success, and an error code on an error.
    142  *
    143  * As a special case, if the first argument is NULL, then it will
    144  * attempt to free the static zeroizing buffer.  (This is to keep
    145  * programs that check for memory leaks happy.)
    146  */
    147 #define STRIDE_LENGTH 8
    148 errcode_t ext2fs_zero_blocks(ext2_filsys fs, blk_t blk, int num,
    149 			     blk_t *ret_blk, int *ret_count)
    150 {
    151 	int		j, count;
    152 	static char	*buf;
    153 	errcode_t	retval;
    154 
    155 	/* If fs is null, clean up the static buffer and return */
    156 	if (!fs) {
    157 		if (buf) {
    158 			free(buf);
    159 			buf = 0;
    160 		}
    161 		return 0;
    162 	}
    163 	/* Allocate the zeroizing buffer if necessary */
    164 	if (!buf) {
    165 		buf = malloc(fs->blocksize * STRIDE_LENGTH);
    166 		if (!buf)
    167 			return ENOMEM;
    168 		memset(buf, 0, fs->blocksize * STRIDE_LENGTH);
    169 	}
    170 	/* OK, do the write loop */
    171 	j=0;
    172 	while (j < num) {
    173 		if (blk % STRIDE_LENGTH) {
    174 			count = STRIDE_LENGTH - (blk % STRIDE_LENGTH);
    175 			if (count > (num - j))
    176 				count = num - j;
    177 		} else {
    178 			count = num - j;
    179 			if (count > STRIDE_LENGTH)
    180 				count = STRIDE_LENGTH;
    181 		}
    182 		retval = io_channel_write_blk(fs->io, blk, count, buf);
    183 		if (retval) {
    184 			if (ret_count)
    185 				*ret_count = count;
    186 			if (ret_blk)
    187 				*ret_blk = blk;
    188 			return retval;
    189 		}
    190 		j += count; blk += count;
    191 	}
    192 	return 0;
    193 }
    194 
    195 /*
    196  * Helper function for creating the journal using direct I/O routines
    197  */
    198 struct mkjournal_struct {
    199 	int		num_blocks;
    200 	int		newblocks;
    201 	blk_t		goal;
    202 	blk_t		blk_to_zero;
    203 	int		zero_count;
    204 	char		*buf;
    205 	errcode_t	err;
    206 };
    207 
    208 static int mkjournal_proc(ext2_filsys	fs,
    209 			   blk_t	*blocknr,
    210 			   e2_blkcnt_t	blockcnt,
    211 			   blk_t	ref_block EXT2FS_ATTR((unused)),
    212 			   int		ref_offset EXT2FS_ATTR((unused)),
    213 			   void		*priv_data)
    214 {
    215 	struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data;
    216 	blk_t	new_blk;
    217 	errcode_t	retval;
    218 
    219 	if (*blocknr) {
    220 		es->goal = *blocknr;
    221 		return 0;
    222 	}
    223 	retval = ext2fs_new_block(fs, es->goal, 0, &new_blk);
    224 	if (retval) {
    225 		es->err = retval;
    226 		return BLOCK_ABORT;
    227 	}
    228 	if (blockcnt >= 0)
    229 		es->num_blocks--;
    230 
    231 	es->newblocks++;
    232 	retval = 0;
    233 	if (blockcnt <= 0)
    234 		retval = io_channel_write_blk(fs->io, new_blk, 1, es->buf);
    235 	else {
    236 		if (es->zero_count) {
    237 			if ((es->blk_to_zero + es->zero_count == new_blk) &&
    238 			    (es->zero_count < 1024))
    239 				es->zero_count++;
    240 			else {
    241 				retval = ext2fs_zero_blocks(fs,
    242 							    es->blk_to_zero,
    243 							    es->zero_count,
    244 							    0, 0);
    245 				es->zero_count = 0;
    246 			}
    247 		}
    248 		if (es->zero_count == 0) {
    249 			es->blk_to_zero = new_blk;
    250 			es->zero_count = 1;
    251 		}
    252 	}
    253 
    254 	if (blockcnt == 0)
    255 		memset(es->buf, 0, fs->blocksize);
    256 
    257 	if (retval) {
    258 		es->err = retval;
    259 		return BLOCK_ABORT;
    260 	}
    261 	*blocknr = es->goal = new_blk;
    262 	ext2fs_block_alloc_stats(fs, new_blk, +1);
    263 
    264 	if (es->num_blocks == 0)
    265 		return (BLOCK_CHANGED | BLOCK_ABORT);
    266 	else
    267 		return BLOCK_CHANGED;
    268 
    269 }
    270 
    271 /*
    272  * This function creates a journal using direct I/O routines.
    273  */
    274 static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
    275 				     blk_t size, int flags)
    276 {
    277 	char			*buf;
    278 	dgrp_t			group, start, end, i, log_flex;
    279 	errcode_t		retval;
    280 	struct ext2_inode	inode;
    281 	struct mkjournal_struct	es;
    282 
    283 	if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
    284 		return retval;
    285 
    286 	if ((retval = ext2fs_read_bitmaps(fs)))
    287 		return retval;
    288 
    289 	if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
    290 		return retval;
    291 
    292 	if (inode.i_blocks > 0)
    293 		return EEXIST;
    294 
    295 	es.num_blocks = size;
    296 	es.newblocks = 0;
    297 	es.buf = buf;
    298 	es.err = 0;
    299 	es.zero_count = 0;
    300 
    301 	if (fs->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS) {
    302 		inode.i_flags |= EXT4_EXTENTS_FL;
    303 		if ((retval = ext2fs_write_inode(fs, journal_ino, &inode)))
    304 			return retval;
    305 	}
    306 
    307 	/*
    308 	 * Set the initial goal block to be roughly at the middle of
    309 	 * the filesystem.  Pick a group that has the largest number
    310 	 * of free blocks.
    311 	 */
    312 	group = ext2fs_group_of_blk(fs, (fs->super->s_blocks_count -
    313 					 fs->super->s_first_data_block) / 2);
    314 	log_flex = 1 << fs->super->s_log_groups_per_flex;
    315 	if (fs->super->s_log_groups_per_flex && (group > log_flex)) {
    316 		group = group & ~(log_flex - 1);
    317 		while ((group < fs->group_desc_count) &&
    318 		       fs->group_desc[group].bg_free_blocks_count == 0)
    319 			group++;
    320 		if (group == fs->group_desc_count)
    321 			group = 0;
    322 		start = group;
    323 	} else
    324 		start = (group > 0) ? group-1 : group;
    325 	end = ((group+1) < fs->group_desc_count) ? group+1 : group;
    326 	group = start;
    327 	for (i=start+1; i <= end; i++)
    328 		if (fs->group_desc[i].bg_free_blocks_count >
    329 		    fs->group_desc[group].bg_free_blocks_count)
    330 			group = i;
    331 
    332 	es.goal = (fs->super->s_blocks_per_group * group) +
    333 		fs->super->s_first_data_block;
    334 
    335 	retval = ext2fs_block_iterate2(fs, journal_ino, BLOCK_FLAG_APPEND,
    336 				       0, mkjournal_proc, &es);
    337 	if (es.err) {
    338 		retval = es.err;
    339 		goto errout;
    340 	}
    341 	if (es.zero_count) {
    342 		retval = ext2fs_zero_blocks(fs, es.blk_to_zero,
    343 					    es.zero_count, 0, 0);
    344 		if (retval)
    345 			goto errout;
    346 	}
    347 
    348 	if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
    349 		goto errout;
    350 
    351  	inode.i_size += fs->blocksize * size;
    352 	ext2fs_iblk_add_blocks(fs, &inode, es.newblocks);
    353 	inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0);
    354 	inode.i_links_count = 1;
    355 	inode.i_mode = LINUX_S_IFREG | 0600;
    356 
    357 	if ((retval = ext2fs_write_new_inode(fs, journal_ino, &inode)))
    358 		goto errout;
    359 	retval = 0;
    360 
    361 	memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
    362 	fs->super->s_jnl_blocks[16] = inode.i_size;
    363 	fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
    364 	ext2fs_mark_super_dirty(fs);
    365 
    366 errout:
    367 	ext2fs_free_mem(&buf);
    368 	return retval;
    369 }
    370 
    371 /*
    372  * Find a reasonable journal file size (in blocks) given the number of blocks
    373  * in the filesystem.  For very small filesystems, it is not reasonable to
    374  * have a journal that fills more than half of the filesystem.
    375  */
    376 int ext2fs_default_journal_size(__u64 blocks)
    377 {
    378 	if (blocks < 2048)
    379 		return -1;
    380 	if (blocks < 32768)
    381 		return (1024);
    382 	if (blocks < 256*1024)
    383 		return (4096);
    384 	if (blocks < 512*1024)
    385 		return (8192);
    386 	if (blocks < 1024*1024)
    387 		return (16384);
    388 	return 32768;
    389 }
    390 
    391 /*
    392  * This function adds a journal device to a filesystem
    393  */
    394 errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
    395 {
    396 	struct stat	st;
    397 	errcode_t	retval;
    398 	char		buf[1024];
    399 	journal_superblock_t	*jsb;
    400 	int		start;
    401 	__u32		i, nr_users;
    402 
    403 	/* Make sure the device exists and is a block device */
    404 	if (stat(journal_dev->device_name, &st) < 0)
    405 		return errno;
    406 
    407 	if (!S_ISBLK(st.st_mode))
    408 		return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
    409 
    410 	/* Get the journal superblock */
    411 	start = 1;
    412 	if (journal_dev->blocksize == 1024)
    413 		start++;
    414 	if ((retval = io_channel_read_blk(journal_dev->io, start, -1024, buf)))
    415 		return retval;
    416 
    417 	jsb = (journal_superblock_t *) buf;
    418 	if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
    419 	    (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
    420 		return EXT2_ET_NO_JOURNAL_SB;
    421 
    422 	if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize)
    423 		return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
    424 
    425 	/* Check and see if this filesystem has already been added */
    426 	nr_users = ntohl(jsb->s_nr_users);
    427 	for (i=0; i < nr_users; i++) {
    428 		if (memcmp(fs->super->s_uuid,
    429 			   &jsb->s_users[i*16], 16) == 0)
    430 			break;
    431 	}
    432 	if (i >= nr_users) {
    433 		memcpy(&jsb->s_users[nr_users*16],
    434 		       fs->super->s_uuid, 16);
    435 		jsb->s_nr_users = htonl(nr_users+1);
    436 	}
    437 
    438 	/* Writeback the journal superblock */
    439 	if ((retval = io_channel_write_blk(journal_dev->io, start, -1024, buf)))
    440 		return retval;
    441 
    442 	fs->super->s_journal_inum = 0;
    443 	fs->super->s_journal_dev = st.st_rdev;
    444 	memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
    445 	       sizeof(fs->super->s_journal_uuid));
    446 	fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
    447 	ext2fs_mark_super_dirty(fs);
    448 	return 0;
    449 }
    450 
    451 /*
    452  * This function adds a journal inode to a filesystem, using either
    453  * POSIX routines if the filesystem is mounted, or using direct I/O
    454  * functions if it is not.
    455  */
    456 errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t size, int flags)
    457 {
    458 	errcode_t		retval;
    459 	ext2_ino_t		journal_ino;
    460 	struct stat		st;
    461 	char			jfile[1024];
    462 	int			mount_flags, f;
    463 	int			fd = -1;
    464 
    465 	if ((retval = ext2fs_check_mount_point(fs->device_name, &mount_flags,
    466 					       jfile, sizeof(jfile)-10)))
    467 		return retval;
    468 
    469 	if (mount_flags & EXT2_MF_MOUNTED) {
    470 		strcat(jfile, "/.journal");
    471 
    472 		/*
    473 		 * If .../.journal already exists, make sure any
    474 		 * immutable or append-only flags are cleared.
    475 		 */
    476 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
    477 		(void) chflags (jfile, 0);
    478 #else
    479 #if HAVE_EXT2_IOCTLS
    480 		fd = open(jfile, O_RDONLY);
    481 		if (fd >= 0) {
    482 			f = 0;
    483 			ioctl(fd, EXT2_IOC_SETFLAGS, &f);
    484 			close(fd);
    485 		}
    486 #endif
    487 #endif
    488 
    489 		/* Create the journal file */
    490 		if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
    491 			return errno;
    492 
    493 		if ((retval = write_journal_file(fs, jfile, size, flags)))
    494 			goto errout;
    495 
    496 		/* Get inode number of the journal file */
    497 		if (fstat(fd, &st) < 0) {
    498 			retval = errno;
    499 			goto errout;
    500 		}
    501 
    502 #if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
    503 		retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
    504 #else
    505 #if HAVE_EXT2_IOCTLS
    506 		if (ioctl(fd, EXT2_IOC_GETFLAGS, &f) < 0) {
    507 			retval = errno;
    508 			goto errout;
    509 		}
    510 		f |= EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;
    511 		retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
    512 #endif
    513 #endif
    514 		if (retval) {
    515 			retval = errno;
    516 			goto errout;
    517 		}
    518 
    519 		if (close(fd) < 0) {
    520 			retval = errno;
    521 			fd = -1;
    522 			goto errout;
    523 		}
    524 		journal_ino = st.st_ino;
    525 	} else {
    526 		if ((mount_flags & EXT2_MF_BUSY) &&
    527 		    !(fs->flags & EXT2_FLAG_EXCLUSIVE)) {
    528 			retval = EBUSY;
    529 			goto errout;
    530 		}
    531 		journal_ino = EXT2_JOURNAL_INO;
    532 		if ((retval = write_journal_inode(fs, journal_ino,
    533 						  size, flags)))
    534 			return retval;
    535 	}
    536 
    537 	fs->super->s_journal_inum = journal_ino;
    538 	fs->super->s_journal_dev = 0;
    539 	memset(fs->super->s_journal_uuid, 0,
    540 	       sizeof(fs->super->s_journal_uuid));
    541 	fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
    542 
    543 	ext2fs_mark_super_dirty(fs);
    544 	return 0;
    545 errout:
    546 	if (fd > 0)
    547 		close(fd);
    548 	return retval;
    549 }
    550 
    551 #ifdef DEBUG
    552 main(int argc, char **argv)
    553 {
    554 	errcode_t	retval;
    555 	char		*device_name;
    556 	ext2_filsys 	fs;
    557 
    558 	if (argc < 2) {
    559 		fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
    560 		exit(1);
    561 	}
    562 	device_name = argv[1];
    563 
    564 	retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
    565 			      unix_io_manager, &fs);
    566 	if (retval) {
    567 		com_err(argv[0], retval, "while opening %s", device_name);
    568 		exit(1);
    569 	}
    570 
    571 	retval = ext2fs_add_journal_inode(fs, 1024);
    572 	if (retval) {
    573 		com_err(argv[0], retval, "while adding journal to %s",
    574 			device_name);
    575 		exit(1);
    576 	}
    577 	retval = ext2fs_flush(fs);
    578 	if (retval) {
    579 		printf("Warning, had trouble writing out superblocks.\n");
    580 	}
    581 	ext2fs_close(fs);
    582 	exit(0);
    583 
    584 }
    585 #endif
    586