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mkjournal.c

/*
 * mkjournal.c --- make a journal for a filesystem
 *
 * Copyright (C) 2000 Theodore Ts'o.
 * 
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 */

#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif
#include <fcntl.h>
#include <time.h>
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

#include "ext2_fs.h"
#include "e2p/e2p.h"
#include "ext2fs.h"
#include "jfs_user.h"

/*
 * This function automatically sets up the journal superblock and
 * returns it as an allocated block.
 */
errcode_t ext2fs_create_journal_superblock(ext2_filsys fs,
                                 __u32 size, int flags,
                                 char  **ret_jsb)
{
      errcode_t         retval;
      journal_superblock_t    *jsb;

      if (size < 1024)
            return EXT2_ET_JOURNAL_TOO_SMALL;

      if ((retval = ext2fs_get_mem(fs->blocksize, &jsb)))
            return retval;

      memset (jsb, 0, fs->blocksize);

      jsb->s_header.h_magic = htonl(JFS_MAGIC_NUMBER);
      if (flags & EXT2_MKJOURNAL_V1_SUPER)
            jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V1);
      else
            jsb->s_header.h_blocktype = htonl(JFS_SUPERBLOCK_V2);
      jsb->s_blocksize = htonl(fs->blocksize);
      jsb->s_maxlen = htonl(size);
      jsb->s_nr_users = htonl(1);
      jsb->s_first = htonl(1);
      jsb->s_sequence = htonl(1);
      memcpy(jsb->s_uuid, fs->super->s_uuid, sizeof(fs->super->s_uuid));
      /*
       * If we're creating an external journal device, we need to
       * adjust these fields.
       */
      if (fs->super->s_feature_incompat &
          EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
            jsb->s_nr_users = 0;
            if (fs->blocksize == 1024)
                  jsb->s_first = htonl(3);
            else
                  jsb->s_first = htonl(2);
      }

      *ret_jsb = (char *) jsb;
      return 0;
}

/*
 * This function writes a journal using POSIX routines.  It is used
 * for creating external journals and creating journals on live
 * filesystems.
 */
static errcode_t write_journal_file(ext2_filsys fs, char *filename,
                            blk_t size, int flags)
{
      errcode_t   retval;
      char        *buf = 0;
      int         fd, ret_size;
      blk_t       i;

      if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
            return retval;

      /* Open the device or journal file */
      if ((fd = open(filename, O_WRONLY)) < 0) {
            retval = errno;
            goto errout;
      }

      /* Write the superblock out */
      retval = EXT2_ET_SHORT_WRITE;
      ret_size = write(fd, buf, fs->blocksize);
      if (ret_size < 0) {
            retval = errno;
            goto errout;
      }
      if (ret_size != (int) fs->blocksize)
            goto errout;
      memset(buf, 0, fs->blocksize);

      for (i = 1; i < size; i++) {
            ret_size = write(fd, buf, fs->blocksize);
            if (ret_size < 0) {
                  retval = errno;
                  goto errout;
            }
            if (ret_size != (int) fs->blocksize)
                  goto errout;
      }
      close(fd);

      retval = 0;
errout:
      ext2fs_free_mem(&buf);
      return retval;
}

/*
 * Helper function for creating the journal using direct I/O routines
 */
struct mkjournal_struct {
      int         num_blocks;
      int         newblocks;
      char        *buf;
      errcode_t   err;
};

static int mkjournal_proc(ext2_filsys     fs,
                     blk_t    *blocknr,
                     e2_blkcnt_t    blockcnt,
                     blk_t    ref_block EXT2FS_ATTR((unused)),
                     int            ref_offset EXT2FS_ATTR((unused)),
                     void           *priv_data)
{
      struct mkjournal_struct *es = (struct mkjournal_struct *) priv_data;
      blk_t new_blk;
      static blk_t      last_blk = 0;
      errcode_t   retval;
      
      if (*blocknr) {
            last_blk = *blocknr;
            return 0;
      }
      retval = ext2fs_new_block(fs, last_blk, 0, &new_blk);
      if (retval) {
            es->err = retval;
            return BLOCK_ABORT;
      }
      if (blockcnt > 0)
            es->num_blocks--;

      es->newblocks++;
      retval = io_channel_write_blk(fs->io, new_blk, 1, es->buf);

      if (blockcnt == 0)
            memset(es->buf, 0, fs->blocksize);

      if (retval) {
            es->err = retval;
            return BLOCK_ABORT;
      }
      *blocknr = new_blk;
      last_blk = new_blk;
      ext2fs_block_alloc_stats(fs, new_blk, +1);

      if (es->num_blocks == 0)
            return (BLOCK_CHANGED | BLOCK_ABORT);
      else
            return BLOCK_CHANGED;
      
}

/*
 * This function creates a journal using direct I/O routines.
 */
static errcode_t write_journal_inode(ext2_filsys fs, ext2_ino_t journal_ino,
                             blk_t size, int flags)
{
      char              *buf;
      errcode_t         retval;
      struct ext2_inode inode;
      struct mkjournal_struct es;

      if ((retval = ext2fs_create_journal_superblock(fs, size, flags, &buf)))
            return retval;
      
      if ((retval = ext2fs_read_bitmaps(fs)))
            return retval;

      if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
            return retval;

      if (inode.i_blocks > 0)
            return EEXIST;

      es.num_blocks = size;
      es.newblocks = 0;
      es.buf = buf;
      es.err = 0;

      retval = ext2fs_block_iterate2(fs, journal_ino, BLOCK_FLAG_APPEND,
                               0, mkjournal_proc, &es);
      if (es.err) {
            retval = es.err;
            goto errout;
      }

      if ((retval = ext2fs_read_inode(fs, journal_ino, &inode)))
            goto errout;

      inode.i_size += fs->blocksize * size;
      inode.i_blocks += (fs->blocksize / 512) * es.newblocks;
      inode.i_mtime = inode.i_ctime = fs->now ? fs->now : time(0);
      inode.i_links_count = 1;
      inode.i_mode = LINUX_S_IFREG | 0600;

      if ((retval = ext2fs_write_inode(fs, journal_ino, &inode)))
            goto errout;
      retval = 0;

      memcpy(fs->super->s_jnl_blocks, inode.i_block, EXT2_N_BLOCKS*4);
      fs->super->s_jnl_blocks[16] = inode.i_size;
      fs->super->s_jnl_backup_type = EXT3_JNL_BACKUP_BLOCKS;
      ext2fs_mark_super_dirty(fs);

errout:
      ext2fs_free_mem(&buf);
      return retval;
}

/*
 * Find a reasonable journal file size (in blocks) given the number of blocks
 * in the filesystem.  For very small filesystems, it is not reasonable to
 * have a journal that fills more than half of the filesystem.
 */
int ext2fs_default_journal_size(__u64 blocks)
{
      if (blocks < 2048)
            return -1;
      if (blocks < 32768)
            return (1024);
      if (blocks < 256*1024)
            return (4096);
      if (blocks < 512*1024)
            return (8192);
      if (blocks < 1024*1024)
            return (16384);
      return 32768;
}

/*
 * This function adds a journal device to a filesystem
 */
errcode_t ext2fs_add_journal_device(ext2_filsys fs, ext2_filsys journal_dev)
{
      struct stat st;
      errcode_t   retval;
      char        buf[1024];
      journal_superblock_t    *jsb;
      int         start;
      __u32       i, nr_users;

      /* Make sure the device exists and is a block device */
      if (stat(journal_dev->device_name, &st) < 0)
            return errno;
      
      if (!S_ISBLK(st.st_mode))
            return EXT2_ET_JOURNAL_NOT_BLOCK; /* Must be a block device */

      /* Get the journal superblock */
      start = 1;
      if (journal_dev->blocksize == 1024)
            start++;
      if ((retval = io_channel_read_blk(journal_dev->io, start, -1024, buf)))
            return retval;

      jsb = (journal_superblock_t *) buf;
      if ((jsb->s_header.h_magic != (unsigned) ntohl(JFS_MAGIC_NUMBER)) ||
          (jsb->s_header.h_blocktype != (unsigned) ntohl(JFS_SUPERBLOCK_V2)))
            return EXT2_ET_NO_JOURNAL_SB;

      if (ntohl(jsb->s_blocksize) != (unsigned long) fs->blocksize)
            return EXT2_ET_UNEXPECTED_BLOCK_SIZE;

      /* Check and see if this filesystem has already been added */
      nr_users = ntohl(jsb->s_nr_users);
      for (i=0; i < nr_users; i++) {
            if (memcmp(fs->super->s_uuid,
                     &jsb->s_users[i*16], 16) == 0)
                  break;
      }
      if (i >= nr_users) {
            memcpy(&jsb->s_users[nr_users*16],
                   fs->super->s_uuid, 16);
            jsb->s_nr_users = htonl(nr_users+1);
      }

      /* Writeback the journal superblock */
      if ((retval = io_channel_write_blk(journal_dev->io, start, -1024, buf)))
            return retval;
      
      fs->super->s_journal_inum = 0;
      fs->super->s_journal_dev = st.st_rdev;
      memcpy(fs->super->s_journal_uuid, jsb->s_uuid,
             sizeof(fs->super->s_journal_uuid));
      fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;
      ext2fs_mark_super_dirty(fs);
      return 0;
}

/*
 * This function adds a journal inode to a filesystem, using either
 * POSIX routines if the filesystem is mounted, or using direct I/O
 * functions if it is not.
 */
errcode_t ext2fs_add_journal_inode(ext2_filsys fs, blk_t size, int flags)
{
      errcode_t         retval;
      ext2_ino_t        journal_ino;
      struct stat       st;
      char              jfile[1024];
      int               mount_flags, f;
      int               fd = -1;

      if ((retval = ext2fs_check_mount_point(fs->device_name, &mount_flags,
                                     jfile, sizeof(jfile)-10)))
            return retval;

      if (mount_flags & EXT2_MF_MOUNTED) {
            strcat(jfile, "/.journal");

            /*
             * If .../.journal already exists, make sure any 
             * immutable or append-only flags are cleared.
             */
#if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
            (void) chflags (jfile, 0);
#else
#if HAVE_EXT2_IOCTLS
            fd = open(jfile, O_RDONLY);
            if (fd >= 0) {
                  f = 0;
                  ioctl(fd, EXT2_IOC_SETFLAGS, &f);
                  close(fd);
            }
#endif
#endif

            /* Create the journal file */
            if ((fd = open(jfile, O_CREAT|O_WRONLY, 0600)) < 0)
                  return errno;

            if ((retval = write_journal_file(fs, jfile, size, flags)))
                  goto errout;
            
            /* Get inode number of the journal file */
            if (fstat(fd, &st) < 0)
                  goto errout;

#if defined(HAVE_CHFLAGS) && defined(UF_NODUMP)
            retval = fchflags (fd, UF_NODUMP|UF_IMMUTABLE);
#else
#if HAVE_EXT2_IOCTLS
            f = EXT2_NODUMP_FL | EXT2_IMMUTABLE_FL;
            retval = ioctl(fd, EXT2_IOC_SETFLAGS, &f);
#endif
#endif
            if (retval)
                  goto errout;
            
            close(fd);
            journal_ino = st.st_ino;
      } else {
            if ((mount_flags & EXT2_MF_BUSY) &&
                !(fs->flags & EXT2_FLAG_EXCLUSIVE)) {
                  retval = EBUSY;
                  goto errout;
            }
            journal_ino = EXT2_JOURNAL_INO;
            if ((retval = write_journal_inode(fs, journal_ino,
                                      size, flags)))
                  return retval;
      }
      
      fs->super->s_journal_inum = journal_ino;
      fs->super->s_journal_dev = 0;
      memset(fs->super->s_journal_uuid, 0,
             sizeof(fs->super->s_journal_uuid));
      fs->super->s_feature_compat |= EXT3_FEATURE_COMPAT_HAS_JOURNAL;

      ext2fs_mark_super_dirty(fs);
      return 0;
errout:
      if (fd > 0)
            close(fd);
      return retval;
}

#ifdef DEBUG
main(int argc, char **argv)
{
      errcode_t   retval;
      char        *device_name;
      ext2_filsys       fs;

      if (argc < 2) {
            fprintf(stderr, "Usage: %s filesystem\n", argv[0]);
            exit(1);
      }
      device_name = argv[1];
      
      retval = ext2fs_open (device_name, EXT2_FLAG_RW, 0, 0,
                        unix_io_manager, &fs);
      if (retval) {
            com_err(argv[0], retval, "while opening %s", device_name);
            exit(1);
      }

      retval = ext2fs_add_journal_inode(fs, 1024);
      if (retval) {
            com_err(argv[0], retval, "while adding journal to %s",
                  device_name);
            exit(1);
      }
      retval = ext2fs_flush(fs);
      if (retval) {
            printf("Warning, had trouble writing out superblocks.\n");
      }
      ext2fs_close(fs);
      exit(0);
      
}
#endif

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