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* mkjournal.c --- make a journal for a filesystem
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* Copyright (C) 2000 Theodore Ts'o.
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* This file may be redistributed under the terms of the GNU Public
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#include <sys/types.h>
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#include <sys/ioctl.h>
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#include <netinet/in.h>
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* This function automatically sets up the journal superblock and
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* returns it as an allocated block.
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errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
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__u32 size, int flags,
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journal_superblock_t *jsb;
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return EXT2_ET_JOURNAL_TOO_SMALL;
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if ((retval = ext2fs_get_mem(fs->blocksize, (void **) &jsb)))
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memset (jsb, 0, fs->blocksize);
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jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
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if (flags & EXT2_MKJOURNAL_V1_SUPER)
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jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V1);
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jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
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jsb->s_blocksize = htonl(fs->blocksize);
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jsb->s_maxlen = htonl(size);
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jsb->s_nr_users = htonl(1);
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jsb->s_first = htonl(1);
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jsb->s_sequence = htonl(1);
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memcpy(jsb->s_uuid, fs->super->s_uuid, sizeof(fs->super->s_uuid));
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* If we're creating an external journal device, we need to
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* adjust these fields.
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if (fs->super->s_feature_incompat &
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EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
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if (fs->blocksize == 1024)
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jsb->s_first = htonl(3);
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jsb->s_first = htonl(2);
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*ret_jsb = (char *) jsb;
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* This function writes a journal using POSIX routines. It is used
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* for creating external journals and creating journals on live
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static errcode_t write_journal_file(ext2_filsys fs, char *filename,
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blk_t size, int flags)
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if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
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/* Open the device or journal file */
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if ((fd = open(filename, O_WRONLY)) < 0) {
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/* Write the superblock out */
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retval = EXT2_ET_SHORT_WRITE;
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ret_size = write(fd, buf, fs->blocksize);
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if (ret_size != fs->blocksize)
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memset(buf, 0, fs->blocksize);
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for (i = 1; i < size; i++) {
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ret_size = write(fd, buf, fs->blocksize);
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if (ret_size != fs->blocksize)
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ext2fs_free_mem((void **) &buf);
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* Helper function for creating the journal using direct I/O routines
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struct mkjournal_struct {
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static int mkjournal_proc(ext2_filsys fs,
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e2_blkcnt_t blockcnt,
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struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data;
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static blk_t last_blk = 0;
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retval = ext2fs_new_block(fs, last_blk, 0, &new_blk);
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retval = io_channel_write_blk(fs->io, new_blk, 1, es->buf);
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memset(es->buf, 0, fs->blocksize);
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ext2fs_mark_block_bitmap(fs->block_map, new_blk);
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ext2fs_mark_bb_dirty(fs);
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group = ext2fs_group_of_blk(fs, new_blk);
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fs->group_desc[group].bg_free_blocks_count--;
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fs->super->s_free_blocks_count--;
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ext2fs_mark_super_dirty(fs);
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if (es->num_blocks == 0)
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return (BLOCK_CHANGED | BLOCK_ABORT);
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return BLOCK_CHANGED;
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* This function creates a journal using direct I/O routines.
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static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
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blk_t size, int flags)
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struct ext2_inode inode;
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struct mkjournal_struct es;
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if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
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if ((retval = ext2fs_read_bitmaps(fs)))
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if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
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if (inode.i_blocks > 0)
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es.num_blocks = size;
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retval = ext2fs_block_iterate2(fs, journal_ino, BLOCK_FLAG_APPEND,
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0, mkjournal_proc, &es);
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if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
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inode.i_size += fs->blocksize * size;
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inode.i_blocks += (fs->blocksize / 512) * es.newblocks;
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inode.i_mtime = inode.i_ctime = time(0);
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inode.i_links_count = 1;
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inode.i_mode = LINUX_S_IFREG | 0600;
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if ((retval = ext2fs_write_inode(fs, journal_ino, &inode)))
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ext2fs_free_mem((void **) &buf);
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* This function adds a journal device to a filesystem
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errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
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journal_superblock_t *jsb;
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/* Make sure the device exists and is a block device */
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if (stat(journal_dev->device_name, &st) < 0)
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if (!S_ISBLK(st.st_mode))
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return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */
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/* Get the journal superblock */
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if (journal_dev->blocksize == 1024)
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if ((retval = io_channel_read_blk(journal_dev->io, start, -1024, buf)))
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jsb = (journal_superblock_t *) buf;
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if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
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(jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
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return EXT2_ET_NO_JOURNAL_SB;
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if (ntohl(jsb->s_blocksize) != fs->blocksize)
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return EXT2_ET_UNEXPECTED_BLOCK_SIZE;
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/* Check and see if this filesystem has already been added */
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nr_users = ntohl(jsb->s_nr_users);
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for (i=0; i < nr_users; i++) {
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if (memcmp(fs->super->s_uuid,
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&jsb->s_users[i*16], 16) == 0)
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memcpy(&jsb->s_users[nr_users*16],
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fs->super->s_uuid, 16);
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jsb->s_nr_users = htonl(nr_users+1);
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/* Writeback the journal superblock */
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if ((retval = io_channel_write_blk(journal_dev->io, start, -1024, buf)))
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fs->super->s_journal_inum = 0;
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fs->super->s_journal_dev = st.st_rdev;
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memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
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sizeof(fs->super->s_journal_uuid));
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fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
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ext2fs_mark_super_dirty(fs);
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* This function adds a journal inode to a filesystem, using either
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* POSIX routines if the filesystem is mounted, or using direct I/O
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* functions if it is not.
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errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t size, int flags)
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ext2_ino_t journal_ino;
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int fd, mount_flags, f;
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if ((retval = ext2fs_check_mount_point(fs->device_name, &mount_flags,
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jfile, sizeof(jfile)-10)))
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if (mount_flags & EXT2_MF_MOUNTED) {
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strcat(jfile, "/.journal");
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/* Create the journal file */
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if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
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if ((retval = write_journal_file(fs, jfile, size, flags)))
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/* Get inode number of the journal file */
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if (fstat(fd, &st) < 0)
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#if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
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retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
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f = EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;;
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retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
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journal_ino = st.st_ino;
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journal_ino = EXT2_JOURNAL_INO;
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if ((retval = write_journal_inode(fs, journal_ino,
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fs->super->s_journal_inum = journal_ino;
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fs->super->s_journal_dev = 0;
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memset(fs->super->s_journal_uuid, 0,
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sizeof(fs->super->s_journal_uuid));
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fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
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ext2fs_mark_super_dirty(fs);
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main(int argc, char **argv)
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fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
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device_name = argv[1];
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retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
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unix_io_manager, &fs);
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com_err(argv[0], retval, "while opening %s", device_name);
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retval = ext2fs_add_journal_inode(fs, 1024);
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com_err(argv[0], retval, "while adding journal to %s",
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retval = ext2fs_flush(fs);
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printf("Warning, had trouble writing out superblocks.\n");