/*
* Clear the MMP usage in the filesystem. If this function returns an
* error EXT2_ET_MMP_CHANGE_ABORT it means the filesystem was modified
* by some other process while in use, and changes should be dropped, or
* risk filesystem corruption.
*/
errcode_t ext2fs_mmp_stop(ext2_filsys fs)
{
struct mmp_struct *mmp, *mmp_cmp;
errcode_t retval = 0;
if (!(fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_MMP) ||
!(fs->flags & EXT2_FLAG_RW) || (fs->flags & EXT2_FLAG_SKIP_MMP))
goto mmp_error;
retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block, fs->mmp_buf);
if (retval)
goto mmp_error;
/* Check if the MMP block is not changed. */
mmp = fs->mmp_buf;
mmp_cmp = fs->mmp_cmp;
if (memcmp(mmp, mmp_cmp, sizeof(*mmp_cmp))) {
retval = EXT2_ET_MMP_CHANGE_ABORT;
goto mmp_error;
}
mmp_cmp->mmp_seq = EXT4_MMP_SEQ_CLEAN;
retval = ext2fs_mmp_write(fs, fs->super->s_mmp_block, fs->mmp_cmp);
mmp_error:
if (fs->mmp_fd > 0) {
close(fs->mmp_fd);
fs->mmp_fd = -1;
}
return retval;
}
/*
* Update the on-disk mmp buffer, after checking that it hasn't been changed.
*/
errcode_t ext2fs_mmp_update(ext2_filsys fs)
{
struct mmp_struct *mmp, *mmp_cmp;
struct timeval tv;
errcode_t retval = 0;
if (!(fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_MMP) ||
!(fs->flags & EXT2_FLAG_RW) || (fs->flags & EXT2_FLAG_SKIP_MMP))
return 0;
gettimeofday(&tv, 0);
if (tv.tv_sec - fs->mmp_last_written < EXT2_MIN_MMP_UPDATE_INTERVAL)
return 0;
retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block, NULL);
if (retval)
goto mmp_error;
mmp = fs->mmp_buf;
mmp_cmp = fs->mmp_cmp;
if (memcmp(mmp, mmp_cmp, sizeof(*mmp_cmp)))
return EXT2_ET_MMP_CHANGE_ABORT;
mmp->mmp_time = tv.tv_sec;
mmp->mmp_seq = EXT4_MMP_SEQ_FSCK;
retval = ext2fs_mmp_write(fs, fs->super->s_mmp_block, fs->mmp_buf);
mmp_error:
return retval;
}
void do_set_mmp_value(int argc, char *argv[])
{
const char *usage = "<field> <value>\n"
"\t\"set_mmp_value -l\" will list the names of "
"MMP fields\n\twhich can be set.";
static struct field_set_info *smmp;
struct mmp_struct *mmp_s;
errcode_t retval;
if (argc == 2 && strcmp(argv[1], "-l") == 0) {
print_possible_fields(mmp_fields);
return;
}
if (current_fs->super->s_mmp_block == 0) {
com_err(argv[0], 0, "no MMP block allocated\n");
return;
}
if (common_args_process(argc, argv, 2, 3, "set_mmp_value",
usage, CHECK_FS_RW))
return;
mmp_s = current_fs->mmp_buf;
if (mmp_s == NULL) {
retval = ext2fs_get_mem(current_fs->blocksize, &mmp_s);
if (retval) {
com_err(argv[0], retval, "allocating MMP buffer\n");
return;
}
retval = ext2fs_mmp_read(current_fs,
current_fs->super->s_mmp_block, mmp_s);
if (retval) {
com_err(argv[0], retval, "reading MMP block %llu.\n",
(long long)current_fs->super->s_mmp_block);
ext2fs_free_mem(mmp_s);
return;
}
current_fs->mmp_buf = mmp_s;
}
smmp = find_field(mmp_fields, argv[1]);
if (smmp == 0) {
com_err(argv[0], 0, "invalid field specifier: %s", argv[1]);
return;
}
set_mmp = *mmp_s;
if (smmp->func(smmp, argv[1], argv[2]) == 0) {
ext2fs_mmp_write(current_fs, current_fs->super->s_mmp_block,
&set_mmp);
*mmp_s = set_mmp;
}
}
/*
* Make sure that the fs is not mounted or being fsck'ed while opening the fs.
*/
errcode_t ext2fs_mmp_start(ext2_filsys fs)
{
struct mmp_struct *mmp_s;
unsigned seq;
unsigned int mmp_check_interval;
errcode_t retval = 0;
if (fs->mmp_buf == NULL) {
retval = ext2fs_get_mem(fs->blocksize, &fs->mmp_buf);
if (retval)
goto mmp_error;
}
retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block, fs->mmp_buf);
if (retval)
goto mmp_error;
mmp_s = fs->mmp_buf;
mmp_check_interval = fs->super->s_mmp_update_interval;
if (mmp_check_interval < EXT4_MMP_MIN_CHECK_INTERVAL)
mmp_check_interval = EXT4_MMP_MIN_CHECK_INTERVAL;
seq = mmp_s->mmp_seq;
if (seq == EXT4_MMP_SEQ_CLEAN)
goto clean_seq;
if (seq == EXT4_MMP_SEQ_FSCK) {
retval = EXT2_ET_MMP_FSCK_ON;
goto mmp_error;
}
if (seq > EXT4_MMP_SEQ_FSCK) {
retval = EXT2_ET_MMP_UNKNOWN_SEQ;
goto mmp_error;
}
/*
* If check_interval in MMP block is larger, use that instead of
* check_interval from the superblock.
*/
if (mmp_s->mmp_check_interval > mmp_check_interval)
mmp_check_interval = mmp_s->mmp_check_interval;
//sleep(2 * mmp_check_interval + 1);
retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block, fs->mmp_buf);
if (retval)
goto mmp_error;
if (seq != mmp_s->mmp_seq) {
retval = EXT2_ET_MMP_FAILED;
goto mmp_error;
}
clean_seq:
if (!(fs->flags & EXT2_FLAG_RW))
goto mmp_error;
mmp_s->mmp_seq = seq = ext2fs_mmp_new_seq();
#if (0 && (_BSD_SOURCE || _XOPEN_SOURCE >= 500))
gethostname(mmp_s->mmp_nodename, sizeof(mmp_s->mmp_nodename));
#else
strcpy(mmp_s->mmp_nodename, "unknown host");
#endif
strncpy(mmp_s->mmp_bdevname, fs->device_name,
sizeof(mmp_s->mmp_bdevname));
retval = ext2fs_mmp_write(fs, fs->super->s_mmp_block, fs->mmp_buf);
if (retval)
goto mmp_error;
//sleep(2 * mmp_check_interval + 1);
retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block, fs->mmp_buf);
if (retval)
goto mmp_error;
if (seq != mmp_s->mmp_seq) {
retval = EXT2_ET_MMP_FAILED;
goto mmp_error;
}
mmp_s->mmp_seq = EXT4_MMP_SEQ_FSCK;
retval = ext2fs_mmp_write(fs, fs->super->s_mmp_block, fs->mmp_buf);
if (retval)
goto mmp_error;
return 0;
mmp_error:
return retval;
}
