/**
* ubifs_start_scan - create LEB scanning information at start of scan.
* @c: UBIFS file-system description object
* @lnum: logical eraseblock number
* @offs: offset to start at (usually zero)
* @sbuf: scan buffer (must be c->leb_size)
*
* This function returns %0 on success and a negative error code on failure.
*/
struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,
int offs, void *sbuf)
{
struct ubifs_scan_leb *sleb;
int err;
dbg_scan("scan LEB %d:%d", lnum, offs);
sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS);
if (!sleb)
return ERR_PTR(-ENOMEM);
sleb->lnum = lnum;
INIT_LIST_HEAD(&sleb->nodes);
sleb->buf = sbuf;
err = ubi_read(c->ubi, lnum, sbuf + offs, offs, c->leb_size - offs);
if (err && err != -EBADMSG) {
ubifs_err("cannot read %d bytes from LEB %d:%d,"
" error %d", c->leb_size - offs, lnum, offs, err);
kfree(sleb);
return ERR_PTR(err);
}
if (err == -EBADMSG)
sleb->ecc = 1;
return sleb;
}
/**
* ubifs_read_node - read node.
* @c: UBIFS file-system description object
* @buf: buffer to read to
* @type: node type
* @len: node length (not aligned)
* @lnum: logical eraseblock number
* @offs: offset within the logical eraseblock
*
* This function reads a node of known type and and length, checks it and
* stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
* and a negative error code in case of failure.
*/
int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
int lnum, int offs)
{
int err, l;
struct ubifs_ch *ch = buf;
int try_count = 0;
dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
ubifs_assert(lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
ubifs_assert(len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
ubifs_assert(!(offs & 7) && offs < c->leb_size);
ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
try_read:
err = ubi_read(c->ubi, lnum, buf, offs, len);
if (err && err != -EBADMSG) {
ubifs_err("cannot read node %d from LEB %d:%d, error %d",
type, lnum, offs, err);
return err;
}
if (type != ch->node_type) {
ubifs_err("bad node type (%d but expected %d)",
ch->node_type, type);
goto out;
}
err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
if (err) {
ubifs_err("expected node type %d", type);
if(try_count < 3){
try_count++;
udelay(100);
goto try_read;
}
else{
return err;
}
}
l = le32_to_cpu(ch->len);
if (l != len) {
ubifs_err("bad node length %d, expected %d", l, len);
goto out;
}
return 0;
out:
ubifs_err("bad node at LEB %d:%d, LEB mapping status %d", lnum, offs,
ubi_is_mapped(c->ubi, lnum));
dbg_dump_node(c, buf);
dbg_dump_stack();
return -EINVAL;
}
int ubifs_leb_read(const struct ubifs_info *c, int lnum, void *buf, int offs,
int len, int even_ebadmsg)
{
int err;
err = ubi_read(c->ubi, lnum, buf, offs, len);
/*
* In case of %-EBADMSG print the error message only if the
* @even_ebadmsg is true.
*/
if (err && (err != -EBADMSG || even_ebadmsg)) {
ubifs_err("reading %d bytes from LEB %d:%d failed, error %d",
len, lnum, offs, err);
dbg_dump_stack();
}
return err;
}
/**
* fixup_leb - fixup/unmap an LEB containing free space.
* @c: UBIFS file-system description object
* @lnum: the LEB number to fix up
* @len: number of used bytes in LEB (starting at offset 0)
*
* This function reads the contents of the given LEB number @lnum, then fixes
* it up, so that empty min. I/O units in the end of LEB are actually erased on
* flash (rather than being just all-0xff real data). If the LEB is completely
* empty, it is simply unmapped.
*/
static int fixup_leb(struct ubifs_info *c, int lnum, int len)
{
int err;
ubifs_assert(len >= 0);
ubifs_assert(len % c->min_io_size == 0);
ubifs_assert(len < c->leb_size);
if (len == 0) {
dbg_mnt("unmap empty LEB %d", lnum);
return ubi_leb_unmap(c->ubi, lnum);
}
dbg_mnt("fixup LEB %d, data len %d", lnum, len);
err = ubi_read(c->ubi, lnum, c->sbuf, 0, len);
if (err)
return err;
return ubi_leb_change(c->ubi, lnum, c->sbuf, len, UBI_UNKNOWN);
}
/**
* ubifs_read_node_wbuf - read node from the media or write-buffer.
* @wbuf: wbuf to check for un-written data
* @buf: buffer to read to
* @type: node type
* @len: node length
* @lnum: logical eraseblock number
* @offs: offset within the logical eraseblock
*
* This function reads a node of known type and length, checks it and stores
* in @buf. If the node partially or fully sits in the write-buffer, this
* function takes data from the buffer, otherwise it reads the flash media.
* Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative
* error code in case of failure.
*/
int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
int lnum, int offs)
{
const struct ubifs_info *c = wbuf->c;
int err, rlen, overlap;
struct ubifs_ch *ch = buf;
dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs,
dbg_ntype(type), len, dbg_jhead(wbuf->jhead));
ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
ubifs_assert(!(offs & 7) && offs < c->leb_size);
ubifs_assert(type >= 0 && type < UBIFS_NODE_TYPES_CNT);
spin_lock(&wbuf->lock);
overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
if (!overlap) {
/* We may safely unlock the write-buffer and read the data */
spin_unlock(&wbuf->lock);
return ubifs_read_node(c, buf, type, len, lnum, offs);
}
/* Don't read under wbuf */
rlen = wbuf->offs - offs;
if (rlen < 0)
rlen = 0;
/* Copy the rest from the write-buffer */
memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
spin_unlock(&wbuf->lock);
if (rlen > 0) {
/* Read everything that goes before write-buffer */
err = ubi_read(c->ubi, lnum, buf, offs, rlen);
if (err && err != -EBADMSG) {
ubifs_err("failed to read node %d from LEB %d:%d, "
"error %d", type, lnum, offs, err);
dbg_dump_stack();
return err;
}
}
if (type != ch->node_type) {
ubifs_err("bad node type (%d but expected %d)",
ch->node_type, type);
goto out;
}
err = ubifs_check_node(c, buf, lnum, offs, 0, 0);
if (err) {
ubifs_err("expected node type %d", type);
return err;
}
rlen = le32_to_cpu(ch->len);
if (rlen != len) {
ubifs_err("bad node length %d, expected %d", rlen, len);
goto out;
}
return 0;
out:
ubifs_err("bad node at LEB %d:%d", lnum, offs);
dbg_dump_node(c, buf);
dbg_dump_stack();
return -EINVAL;
}
