/*
* This clever recursive function handles i_blocks[] as well as
* indirect, double indirect, and triple indirect blocks. It iterates
* over the entries in the i_blocks array or indirect blocks, and for
* each one, will recursively handle any indirect blocks and then
* frees and deallocates the blocks.
*/
static errcode_t ind_punch(ext2_filsys fs, struct ext2_inode *inode,
char *block_buf, blk_t *p, int level,
blk_t start, blk_t count, int max)
{
errcode_t retval;
blk_t b;
int i;
blk64_t offset, incr;
int freed = 0;
#ifdef PUNCH_DEBUG
printf("Entering ind_punch, level %d, start %u, count %u, "
"max %d\n", level, start, count, max);
#endif
incr = 1ULL << ((EXT2_BLOCK_SIZE_BITS(fs->super)-2)*level);
for (i=0, offset=0; i < max; i++, p++, offset += incr) {
if (offset >= start + count)
break;
if (*p == 0 || (offset+incr) <= start)
continue;
b = *p;
if (level > 0) {
blk_t start2;
#ifdef PUNCH_DEBUG
printf("Reading indirect block %u\n", b);
#endif
retval = ext2fs_read_ind_block(fs, b, block_buf);
if (retval)
return retval;
start2 = (start > offset) ? start - offset : 0;
retval = ind_punch(fs, inode, block_buf + fs->blocksize,
(blk_t *) block_buf, level - 1,
start2, count - offset,
fs->blocksize >> 2);
if (retval)
return retval;
retval = ext2fs_write_ind_block(fs, b, block_buf);
if (retval)
return retval;
if (!check_zero_block(block_buf, fs->blocksize))
continue;
}
#ifdef PUNCH_DEBUG
printf("Freeing block %u (offset %llu)\n", b, offset);
#endif
ext2fs_block_alloc_stats(fs, b, -1);
*p = 0;
freed++;
}
errcode_t ext2fs_image_inode_write(ext2_filsys fs, int fd, int flags)
{
unsigned int group, left, c, d;
char *buf, *cp;
blk_t blk;
ssize_t actual;
errcode_t retval;
buf = malloc(fs->blocksize * BUF_BLOCKS);
if (!buf)
return ENOMEM;
for (group = 0; group < fs->group_desc_count; group++) {
blk = fs->group_desc[(unsigned)group].bg_inode_table;
if (!blk) {
retval = EXT2_ET_MISSING_INODE_TABLE;
goto errout;
}
left = fs->inode_blocks_per_group;
while (left) {
c = BUF_BLOCKS;
if (c > left)
c = left;
retval = io_channel_read_blk(fs->io, blk, c, buf);
if (retval)
goto errout;
cp = buf;
while (c) {
if (!(flags & IMAGER_FLAG_SPARSEWRITE)) {
d = c;
goto skip_sparse;
}
/* Skip zero blocks */
if (check_zero_block(cp, fs->blocksize)) {
c--;
blk++;
left--;
cp += fs->blocksize;
lseek(fd, fs->blocksize, SEEK_CUR);
continue;
}
/* Find non-zero blocks */
for (d=1; d < c; d++) {
if (check_zero_block(cp + d*fs->blocksize, fs->blocksize))
break;
}
skip_sparse:
actual = write(fd, cp, fs->blocksize * d);
if (actual == -1) {
retval = errno;
goto errout;
}
if (actual != (ssize_t) (fs->blocksize * d)) {
retval = EXT2_ET_SHORT_WRITE;
goto errout;
}
blk += d;
left -= d;
cp += fs->blocksize * d;
c -= d;
}
}
}
retval = 0;
errout:
free(buf);
return retval;
}