static int read_block(struct inode *inode, void *addr, unsigned int block,
struct ubifs_data_node *dn)
{
struct ubifs_info *c = inode->i_sb->s_fs_info;
int err, len, out_len;
union ubifs_key key;
unsigned int dlen;
data_key_init(c, &key, inode->i_ino, block);
err = ubifs_tnc_lookup(c, &key, dn);
if (err) {
if (err == -ENOENT)
/* Not found, so it must be a hole */
memset(addr, 0, UBIFS_BLOCK_SIZE);
return err;
}
ubifs_assert(le64_to_cpu(dn->ch.sqnum) > ubifs_inode(inode)->creat_sqnum);
len = le32_to_cpu(dn->size);
if (len <= 0 || len > UBIFS_BLOCK_SIZE)
goto dump;
dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
out_len = UBIFS_BLOCK_SIZE;
err = ubifs_decompress(&dn->data, dlen, addr, &out_len,
le16_to_cpu(dn->compr_type));
if (err || len != out_len)
goto dump;
/*
* Data length can be less than a full block, even for blocks that are
* not the last in the file (e.g., as a result of making a hole and
* appending data). Ensure that the remainder is zeroed out.
*/
if (len < UBIFS_BLOCK_SIZE)
memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
return 0;
dump:
ubifs_err("bad data node (block %u, inode %lu)",
block, inode->i_ino);
dbg_dump_node(c, dn);
return -EINVAL;
}
/**
* ubifs_jrn_truncate - update the journal for a truncation.
* @c: UBIFS file-system description object
* @inum: inode number of inode being truncated
* @old_size: old size
* @new_size: new size
*
* When the size of a file decreases due to truncation, a truncation node is
* written, the journal tree is updated, and the last data block is re-written
* if it has been affected.
*
* This function returns %0 in the case of success, and a negative error code in
* case of failure.
*/
int ubifs_jrn_truncate(struct ubifs_info *c, ino_t inum,
loff_t old_size, loff_t new_size)
{
union ubifs_key key, to_key;
struct ubifs_trun_node *trun;
struct ubifs_data_node *dn;
int err, dlen, len, lnum, offs, bit, sz;
unsigned int blk;
dbg_jrn("ino %lu, size %lld -> %lld", inum, old_size, new_size);
sz = UBIFS_TRUN_NODE_SZ + UBIFS_MAX_DATA_NODE_SZ * WORST_COMPR_FACTOR;
trun = kmalloc(sz, GFP_NOFS);
if (!trun)
return -ENOMEM;
trun->ch.node_type = UBIFS_TRUN_NODE;
trun_key_init_flash(c, &trun->key, inum);
trun->old_size = cpu_to_le64(old_size);
trun->new_size = cpu_to_le64(new_size);
ubifs_prepare_node(c, trun, UBIFS_TRUN_NODE_SZ, 0);
dlen = new_size & (UBIFS_BLOCK_SIZE - 1);
if (dlen) {
/* Get last data block so it can be truncated */
dn = (void *)trun + ALIGN(UBIFS_TRUN_NODE_SZ, 8);
blk = new_size / UBIFS_BLOCK_SIZE;
data_key_init(c, &key, inum, blk);
dbg_jrn_key(c, &key, "key");
err = ubifs_tnc_lookup(c, &key, dn);
if (err == -ENOENT)
dlen = 0; /* Not found (so it is a hole) */
else if (err)
goto out_free;
else {
if (le32_to_cpu(dn->size) <= dlen)
dlen = 0; /* Nothing to do */
else {
int compr_type = le16_to_cpu(dn->compr_type);
if (compr_type != UBIFS_COMPR_NONE) {
err = recomp_data_node(dn, &dlen);
if (err)
goto out_free;
} else {
dn->size = cpu_to_le32(dlen);
dlen += UBIFS_DATA_NODE_SZ;
}
zero_data_node_unused(dn);
ubifs_prepare_node(c, dn, dlen, 0);
}
}
}
if (dlen)
len = ALIGN(UBIFS_TRUN_NODE_SZ, 8) + dlen;
else
len = UBIFS_TRUN_NODE_SZ;
err = make_reservation(c, BASEHD, len);
if (err)
goto out_free;
err = write_head(c, BASEHD, trun, len, &lnum, &offs, 0);
if (!err)
ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf, inum);
release_head(c, BASEHD);
if (err)
goto out_ro;
if (dlen) {
offs += ALIGN(UBIFS_TRUN_NODE_SZ, 8);
err = ubifs_tnc_add(c, &key, lnum, offs, dlen);
if (err)
goto out_ro;
}
err = ubifs_add_dirt(c, lnum, UBIFS_TRUN_NODE_SZ);
if (err)
goto out_ro;
bit = new_size & (UBIFS_BLOCK_SIZE - 1);
blk = new_size / UBIFS_BLOCK_SIZE + (bit ? 1 : 0);
data_key_init(c, &key, inum, blk);
bit = old_size & (UBIFS_BLOCK_SIZE - 1);
blk = old_size / UBIFS_BLOCK_SIZE - (bit ? 0: 1);
data_key_init(c, &to_key, inum, blk);
err = ubifs_tnc_remove_range(c, &key, &to_key);
if (err)
goto out_ro;
finish_reservation(c);
kfree(trun);
return 0;
out_ro:
ubifs_ro_mode(c, err);
finish_reservation(c);
out_free:
kfree(trun);
return err;
}
