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lpt_commit.c
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lpt_commit.c
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/*
* This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Authors: Adrian Hunter
* Artem Bityutskiy (Битюцкий Артём)
*/
/*
* This file implements commit-related functionality of the LEB properties
* subsystem.
*/
#include <linux/crc16.h>
#include "ubifs.h"
/**
* first_dirty_cnode - find first dirty cnode.
* @c: UBIFS file-system description object
* @nnode: nnode at which to start
*
* This function returns the first dirty cnode or %NULL if there is not one.
*/
static struct ubifs_cnode *first_dirty_cnode(struct ubifs_nnode *nnode)
{
ubifs_assert(nnode);
while (1) {
int i, cont = 0;
for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
struct ubifs_cnode *cnode;
cnode = nnode->nbranch[i].cnode;
if (cnode &&
test_bit(DIRTY_CNODE, &cnode->flags)) {
if (cnode->level == 0)
return cnode;
nnode = (struct ubifs_nnode *)cnode;
cont = 1;
break;
}
}
if (!cont)
return (struct ubifs_cnode *)nnode;
}
}
/**
* next_dirty_cnode - find next dirty cnode.
* @cnode: cnode from which to begin searching
*
* This function returns the next dirty cnode or %NULL if there is not one.
*/
static struct ubifs_cnode *next_dirty_cnode(struct ubifs_cnode *cnode)
{
struct ubifs_nnode *nnode;
int i;
ubifs_assert(cnode);
nnode = cnode->parent;
if (!nnode)
return NULL;
for (i = cnode->iip + 1; i < UBIFS_LPT_FANOUT; i++) {
cnode = nnode->nbranch[i].cnode;
if (cnode && test_bit(DIRTY_CNODE, &cnode->flags)) {
if (cnode->level == 0)
return cnode; /* cnode is a pnode */
/* cnode is a nnode */
return first_dirty_cnode((struct ubifs_nnode *)cnode);
}
}
return (struct ubifs_cnode *)nnode;
}
/**
* get_cnodes_to_commit - create list of dirty cnodes to commit.
* @c: UBIFS file-system description object
*
* This function returns the number of cnodes to commit.
*/
static int get_cnodes_to_commit(struct ubifs_info *c)
{
struct ubifs_cnode *cnode, *cnext;
int cnt = 0;
if (!c->nroot)
return 0;
if (!test_bit(DIRTY_CNODE, &c->nroot->flags))
return 0;
c->lpt_cnext = first_dirty_cnode(c->nroot);
cnode = c->lpt_cnext;
if (!cnode)
return 0;
cnt += 1;
while (1) {
ubifs_assert(!test_bit(COW_ZNODE, &cnode->flags));
__set_bit(COW_ZNODE, &cnode->flags);
cnext = next_dirty_cnode(cnode);
if (!cnext) {
cnode->cnext = c->lpt_cnext;
break;
}
cnode->cnext = cnext;
cnode = cnext;
cnt += 1;
}
dbg_cmt("committing %d cnodes", cnt);
dbg_lp("committing %d cnodes", cnt);
ubifs_assert(cnt == c->dirty_nn_cnt + c->dirty_pn_cnt);
return cnt;
}
/**
* upd_ltab - update LPT LEB properties.
* @c: UBIFS file-system description object
* @lnum: LEB number
* @free: amount of free space
* @dirty: amount of dirty space to add
*/
static void upd_ltab(struct ubifs_info *c, int lnum, int free, int dirty)
{
dbg_lp("LEB %d free %d dirty %d to %d +%d",
lnum, c->ltab[lnum - c->lpt_first].free,
c->ltab[lnum - c->lpt_first].dirty, free, dirty);
ubifs_assert(lnum >= c->lpt_first && lnum <= c->lpt_last);
c->ltab[lnum - c->lpt_first].free = free;
c->ltab[lnum - c->lpt_first].dirty += dirty;
}
/**
* alloc_lpt_leb - allocate an LPT LEB that is empty.
* @c: UBIFS file-system description object
* @lnum: LEB number is passed and returned here
*
* This function finds the next empty LEB in the ltab starting from @lnum. If a
* an empty LEB is found it is returned in @lnum and the function returns %0.
* Otherwise the function returns -ENOSPC. Note however, that LPT is designed
* never to run out of space.
*/
static int alloc_lpt_leb(struct ubifs_info *c, int *lnum)
{
int i, n;
n = *lnum - c->lpt_first + 1;
for (i = n; i < c->lpt_lebs; i++) {
if (c->ltab[i].tgc || c->ltab[i].cmt)
continue;
if (c->ltab[i].free == c->leb_size) {
c->ltab[i].cmt = 1;
*lnum = i + c->lpt_first;
return 0;
}
}
for (i = 0; i < n; i++) {
if (c->ltab[i].tgc || c->ltab[i].cmt)
continue;
if (c->ltab[i].free == c->leb_size) {
c->ltab[i].cmt = 1;
*lnum = i + c->lpt_first;
return 0;
}
}
dbg_err("last LEB %d", *lnum);
dump_stack();
return -ENOSPC;
}
/**
* layout_cnodes - layout cnodes for commit.
* @c: UBIFS file-system description object
*
* This function returns %0 on success and a negative error code on failure.
*/
static int layout_cnodes(struct ubifs_info *c)
{
int lnum, offs, len, alen, done_lsave, done_ltab, err;
struct ubifs_cnode *cnode;
cnode = c->lpt_cnext;
if (!cnode)
return 0;
lnum = c->nhead_lnum;
offs = c->nhead_offs;
/* Try to place lsave and ltab nicely */
done_lsave = !c->big_lpt;
done_ltab = 0;
if (!done_lsave && offs + c->lsave_sz <= c->leb_size) {
done_lsave = 1;
c->lsave_lnum = lnum;
c->lsave_offs = offs;
offs += c->lsave_sz;
}
if (offs + c->ltab_sz <= c->leb_size) {
done_ltab = 1;
c->ltab_lnum = lnum;
c->ltab_offs = offs;
offs += c->ltab_sz;
}
do {
if (cnode->level) {
len = c->nnode_sz;
c->dirty_nn_cnt -= 1;
} else {
len = c->pnode_sz;
c->dirty_pn_cnt -= 1;
}
while (offs + len > c->leb_size) {
alen = ALIGN(offs, c->min_io_size);
upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
err = alloc_lpt_leb(c, &lnum);
if (err)
return err;
offs = 0;
ubifs_assert(lnum >= c->lpt_first &&
lnum <= c->lpt_last);
/* Try to place lsave and ltab nicely */
if (!done_lsave) {
done_lsave = 1;
c->lsave_lnum = lnum;
c->lsave_offs = offs;
offs += c->lsave_sz;
continue;
}
if (!done_ltab) {
done_ltab = 1;
c->ltab_lnum = lnum;
c->ltab_offs = offs;
offs += c->ltab_sz;
continue;
}
break;
}
if (cnode->parent) {
cnode->parent->nbranch[cnode->iip].lnum = lnum;
cnode->parent->nbranch[cnode->iip].offs = offs;
} else {
c->lpt_lnum = lnum;
c->lpt_offs = offs;
}
offs += len;
cnode = cnode->cnext;
} while (cnode && cnode != c->lpt_cnext);
/* Make sure to place LPT's save table */
if (!done_lsave) {
if (offs + c->lsave_sz > c->leb_size) {
alen = ALIGN(offs, c->min_io_size);
upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
err = alloc_lpt_leb(c, &lnum);
if (err)
return err;
offs = 0;
ubifs_assert(lnum >= c->lpt_first &&
lnum <= c->lpt_last);
}
done_lsave = 1;
c->lsave_lnum = lnum;
c->lsave_offs = offs;
offs += c->lsave_sz;
}
/* Make sure to place LPT's own lprops table */
if (!done_ltab) {
if (offs + c->ltab_sz > c->leb_size) {
alen = ALIGN(offs, c->min_io_size);
upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
err = alloc_lpt_leb(c, &lnum);
if (err)
return err;
offs = 0;
ubifs_assert(lnum >= c->lpt_first &&
lnum <= c->lpt_last);
}
done_ltab = 1;
c->ltab_lnum = lnum;
c->ltab_offs = offs;
offs += c->ltab_sz;
}
alen = ALIGN(offs, c->min_io_size);
upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
return 0;
}
/**
* realloc_lpt_leb - allocate an LPT LEB that is empty.
* @c: UBIFS file-system description object
* @lnum: LEB number is passed and returned here
*
* This function duplicates exactly the results of the function alloc_lpt_leb.
* It is used during end commit to reallocate the same LEB numbers that were
* allocated by alloc_lpt_leb during start commit.
*
* This function finds the next LEB that was allocated by the alloc_lpt_leb
* function starting from @lnum. If a LEB is found it is returned in @lnum and
* the function returns %0. Otherwise the function returns -ENOSPC.
* Note however, that LPT is designed never to run out of space.
*/
static int realloc_lpt_leb(struct ubifs_info *c, int *lnum)
{
int i, n;
n = *lnum - c->lpt_first + 1;
for (i = n; i < c->lpt_lebs; i++)
if (c->ltab[i].cmt) {
c->ltab[i].cmt = 0;
*lnum = i + c->lpt_first;
return 0;
}
for (i = 0; i < n; i++)
if (c->ltab[i].cmt) {
c->ltab[i].cmt = 0;
*lnum = i + c->lpt_first;
return 0;
}
dbg_err("last LEB %d", *lnum);
dump_stack();
return -ENOSPC;
}
/**
* write_cnodes - write cnodes for commit.
* @c: UBIFS file-system description object
*
* This function returns %0 on success and a negative error code on failure.
*/
static int write_cnodes(struct ubifs_info *c)
{
int lnum, offs, len, from, err, wlen, alen, done_ltab, done_lsave;
struct ubifs_cnode *cnode;
void *buf = c->lpt_buf;
cnode = c->lpt_cnext;
if (!cnode)
return 0;
lnum = c->nhead_lnum;
offs = c->nhead_offs;
from = offs;
/* Ensure empty LEB is unmapped */
if (offs == 0) {
err = ubifs_leb_unmap(c, lnum);
if (err)
return err;
}
/* Try to place lsave and ltab nicely */
done_lsave = !c->big_lpt;
done_ltab = 0;
if (!done_lsave && offs + c->lsave_sz <= c->leb_size) {
done_lsave = 1;
ubifs_pack_lsave(c, buf + offs, c->lsave);
offs += c->lsave_sz;
}
if (offs + c->ltab_sz <= c->leb_size) {
done_ltab = 1;
ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
offs += c->ltab_sz;
}
/* Loop for each cnode */
do {
if (cnode->level)
len = c->nnode_sz;
else
len = c->pnode_sz;
while (offs + len > c->leb_size) {
wlen = offs - from;
if (wlen) {
alen = ALIGN(wlen, c->min_io_size);
memset(buf + offs, 0xff, alen - wlen);
err = ubifs_leb_write(c, lnum, buf + from, from,
alen, UBI_SHORTTERM);
if (err)
return err;
}
err = realloc_lpt_leb(c, &lnum);
if (err)
return err;
offs = 0;
from = 0;
ubifs_assert(lnum >= c->lpt_first &&
lnum <= c->lpt_last);
err = ubifs_leb_unmap(c, lnum);
if (err)
return err;
/* Try to place lsave and ltab nicely */
if (!done_lsave) {
done_lsave = 1;
ubifs_pack_lsave(c, buf + offs, c->lsave);
offs += c->lsave_sz;
continue;
}
if (!done_ltab) {
done_ltab = 1;
ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
offs += c->ltab_sz;
continue;
}
break;
}
if (cnode->level)
ubifs_pack_nnode(c, buf + offs,
(struct ubifs_nnode *)cnode);
else
ubifs_pack_pnode(c, buf + offs,
(struct ubifs_pnode *)cnode);
/*
* The reason for the barriers is the same as in case of TNC.
* See comment in 'write_index()'. 'dirty_cow_nnode()' and
* 'dirty_cow_pnode()' are the functions for which this is
* important.
*/
clear_bit(DIRTY_CNODE, &cnode->flags);
smp_mb__before_clear_bit();
clear_bit(COW_ZNODE, &cnode->flags);
smp_mb__after_clear_bit();
offs += len;
cnode = cnode->cnext;
} while (cnode && cnode != c->lpt_cnext);
/* Make sure to place LPT's save table */
if (!done_lsave) {
if (offs + c->lsave_sz > c->leb_size) {
wlen = offs - from;
alen = ALIGN(wlen, c->min_io_size);
memset(buf + offs, 0xff, alen - wlen);
err = ubifs_leb_write(c, lnum, buf + from, from, alen,
UBI_SHORTTERM);
if (err)
return err;
err = realloc_lpt_leb(c, &lnum);
if (err)
return err;
offs = 0;
ubifs_assert(lnum >= c->lpt_first &&
lnum <= c->lpt_last);
err = ubifs_leb_unmap(c, lnum);
if (err)
return err;
}
done_lsave = 1;
ubifs_pack_lsave(c, buf + offs, c->lsave);
offs += c->lsave_sz;
}
/* Make sure to place LPT's own lprops table */
if (!done_ltab) {
if (offs + c->ltab_sz > c->leb_size) {
wlen = offs - from;
alen = ALIGN(wlen, c->min_io_size);
memset(buf + offs, 0xff, alen - wlen);
err = ubifs_leb_write(c, lnum, buf + from, from, alen,
UBI_SHORTTERM);
if (err)
return err;
err = realloc_lpt_leb(c, &lnum);
if (err)
return err;
offs = 0;
ubifs_assert(lnum >= c->lpt_first &&
lnum <= c->lpt_last);
err = ubifs_leb_unmap(c, lnum);
if (err)
return err;
}
done_ltab = 1;
ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
offs += c->ltab_sz;
}
/* Write remaining data in buffer */
wlen = offs - from;
alen = ALIGN(wlen, c->min_io_size);
memset(buf + offs, 0xff, alen - wlen);
err = ubifs_leb_write(c, lnum, buf + from, from, alen, UBI_SHORTTERM);
if (err)
return err;
c->nhead_lnum = lnum;
c->nhead_offs = ALIGN(offs, c->min_io_size);
dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
if (c->big_lpt)
dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
return 0;
}
/**
* next_pnode - find next pnode.
* @c: UBIFS file-system description object
* @pnode: pnode
*
* This function returns the next pnode or %NULL if there are no more pnodes.
*/
static struct ubifs_pnode *next_pnode(struct ubifs_info *c,
struct ubifs_pnode *pnode)
{
struct ubifs_nnode *nnode;
int iip;
/* Try to go right */
nnode = pnode->parent;
iip = pnode->iip + 1;
if (iip < UBIFS_LPT_FANOUT) {
/* We assume here that LEB zero is never an LPT LEB */
if (nnode->nbranch[iip].lnum)
return ubifs_get_pnode(c, nnode, iip);
else
return NULL;
}
/* Go up while can't go right */
do {
iip = nnode->iip + 1;
nnode = nnode->parent;
if (!nnode)
return NULL;
/* We assume here that LEB zero is never an LPT LEB */
} while (iip >= UBIFS_LPT_FANOUT || !nnode->nbranch[iip].lnum);
/* Go right */
nnode = ubifs_get_nnode(c, nnode, iip);
if (IS_ERR(nnode))
return (void *)nnode;
/* Go down to level 1 */
while (nnode->level > 1) {
nnode = ubifs_get_nnode(c, nnode, 0);
if (IS_ERR(nnode))
return (void *)nnode;
}
return ubifs_get_pnode(c, nnode, 0);
}
/**
* pnode_lookup - lookup a pnode in the LPT.
* @c: UBIFS file-system description object
* @i: pnode number (0 to main_lebs - 1)
*
* This function returns a pointer to the pnode on success or a negative
* error code on failure.
*/
static struct ubifs_pnode *pnode_lookup(struct ubifs_info *c, int i)
{
int err, h, iip, shft;
struct ubifs_nnode *nnode;
if (!c->nroot) {
err = ubifs_read_nnode(c, NULL, 0);
if (err)
return ERR_PTR(err);
}
i <<= UBIFS_LPT_FANOUT_SHIFT;
nnode = c->nroot;
shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
for (h = 1; h < c->lpt_hght; h++) {
iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
shft -= UBIFS_LPT_FANOUT_SHIFT;
nnode = ubifs_get_nnode(c, nnode, iip);
if (IS_ERR(nnode))
return ERR_PTR(PTR_ERR(nnode));
}
iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
return ubifs_get_pnode(c, nnode, iip);
}
/**
* add_pnode_dirt - add dirty space to LPT LEB properties.
* @c: UBIFS file-system description object
* @pnode: pnode for which to add dirt
*/
static void add_pnode_dirt(struct ubifs_info *c, struct ubifs_pnode *pnode)
{
ubifs_add_lpt_dirt(c, pnode->parent->nbranch[pnode->iip].lnum,
c->pnode_sz);
}
/**
* do_make_pnode_dirty - mark a pnode dirty.
* @c: UBIFS file-system description object
* @pnode: pnode to mark dirty
*/
static void do_make_pnode_dirty(struct ubifs_info *c, struct ubifs_pnode *pnode)
{
/* Assumes cnext list is empty i.e. not called during commit */
if (!test_and_set_bit(DIRTY_CNODE, &pnode->flags)) {
struct ubifs_nnode *nnode;
c->dirty_pn_cnt += 1;
add_pnode_dirt(c, pnode);
/* Mark parent and ancestors dirty too */
nnode = pnode->parent;
while (nnode) {
if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
c->dirty_nn_cnt += 1;
ubifs_add_nnode_dirt(c, nnode);
nnode = nnode->parent;
} else
break;
}
}
}
/**
* make_tree_dirty - mark the entire LEB properties tree dirty.
* @c: UBIFS file-system description object
*
* This function is used by the "small" LPT model to cause the entire LEB
* properties tree to be written. The "small" LPT model does not use LPT
* garbage collection because it is more efficient to write the entire tree
* (because it is small).
*
* This function returns %0 on success and a negative error code on failure.
*/
static int make_tree_dirty(struct ubifs_info *c)
{
struct ubifs_pnode *pnode;
pnode = pnode_lookup(c, 0);
while (pnode) {
do_make_pnode_dirty(c, pnode);
pnode = next_pnode(c, pnode);
if (IS_ERR(pnode))
return PTR_ERR(pnode);
}
return 0;
}
/**
* need_write_all - determine if the LPT area is running out of free space.
* @c: UBIFS file-system description object
*
* This function returns %1 if the LPT area is running out of free space and %0
* if it is not.
*/
static int need_write_all(struct ubifs_info *c)
{
long long free = 0;
int i;
for (i = 0; i < c->lpt_lebs; i++) {
if (i + c->lpt_first == c->nhead_lnum)
free += c->leb_size - c->nhead_offs;
else if (c->ltab[i].free == c->leb_size)
free += c->leb_size;
else if (c->ltab[i].free + c->ltab[i].dirty == c->leb_size)
free += c->leb_size;
}
/* Less than twice the size left */
if (free <= c->lpt_sz * 2)
return 1;
return 0;
}
/**
* lpt_tgc_start - start trivial garbage collection of LPT LEBs.
* @c: UBIFS file-system description object
*
* LPT trivial garbage collection is where a LPT LEB contains only dirty and
* free space and so may be reused as soon as the next commit is completed.
* This function is called during start commit to mark LPT LEBs for trivial GC.
*/
static void lpt_tgc_start(struct ubifs_info *c)
{
int i;
for (i = 0; i < c->lpt_lebs; i++) {
if (i + c->lpt_first == c->nhead_lnum)
continue;
if (c->ltab[i].dirty > 0 &&
c->ltab[i].free + c->ltab[i].dirty == c->leb_size) {
c->ltab[i].tgc = 1;
c->ltab[i].free = c->leb_size;
c->ltab[i].dirty = 0;
dbg_lp("LEB %d", i + c->lpt_first);
}
}
}
/**
* lpt_tgc_end - end trivial garbage collection of LPT LEBs.
* @c: UBIFS file-system description object
*
* LPT trivial garbage collection is where a LPT LEB contains only dirty and
* free space and so may be reused as soon as the next commit is completed.
* This function is called after the commit is completed (master node has been
* written) and unmaps LPT LEBs that were marked for trivial GC.
*/
static int lpt_tgc_end(struct ubifs_info *c)
{
int i, err;
for (i = 0; i < c->lpt_lebs; i++)
if (c->ltab[i].tgc) {
err = ubifs_leb_unmap(c, i + c->lpt_first);
if (err)
return err;
c->ltab[i].tgc = 0;
dbg_lp("LEB %d", i + c->lpt_first);
}
return 0;
}
/**
* populate_lsave - fill the lsave array with important LEB numbers.
* @c: the UBIFS file-system description object
*
* This function is only called for the "big" model. It records a small number
* of LEB numbers of important LEBs. Important LEBs are ones that are (from
* most important to least important): empty, freeable, freeable index, dirty
* index, dirty or free. Upon mount, we read this list of LEB numbers and bring
* their pnodes into memory. That will stop us from having to scan the LPT
* straight away. For the "small" model we assume that scanning the LPT is no
* big deal.
*/
static void populate_lsave(struct ubifs_info *c)
{
struct ubifs_lprops *lprops;
struct ubifs_lpt_heap *heap;
int i, cnt = 0;
ubifs_assert(c->big_lpt);
if (!(c->lpt_drty_flgs & LSAVE_DIRTY)) {
c->lpt_drty_flgs |= LSAVE_DIRTY;
ubifs_add_lpt_dirt(c, c->lsave_lnum, c->lsave_sz);
}
list_for_each_entry(lprops, &c->empty_list, list) {
c->lsave[cnt++] = lprops->lnum;
if (cnt >= c->lsave_cnt)
return;
}
list_for_each_entry(lprops, &c->freeable_list, list) {
c->lsave[cnt++] = lprops->lnum;
if (cnt >= c->lsave_cnt)
return;
}
list_for_each_entry(lprops, &c->frdi_idx_list, list) {
c->lsave[cnt++] = lprops->lnum;
if (cnt >= c->lsave_cnt)
return;
}
heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
for (i = 0; i < heap->cnt; i++) {
c->lsave[cnt++] = heap->arr[i]->lnum;
if (cnt >= c->lsave_cnt)
return;
}
heap = &c->lpt_heap[LPROPS_DIRTY - 1];
for (i = 0; i < heap->cnt; i++) {
c->lsave[cnt++] = heap->arr[i]->lnum;
if (cnt >= c->lsave_cnt)
return;
}
heap = &c->lpt_heap[LPROPS_FREE - 1];
for (i = 0; i < heap->cnt; i++) {
c->lsave[cnt++] = heap->arr[i]->lnum;
if (cnt >= c->lsave_cnt)
return;
}
/* Fill it up completely */
while (cnt < c->lsave_cnt)
c->lsave[cnt++] = c->main_first;
}
/**
* nnode_lookup - lookup a nnode in the LPT.
* @c: UBIFS file-system description object
* @i: nnode number
*
* This function returns a pointer to the nnode on success or a negative
* error code on failure.
*/
static struct ubifs_nnode *nnode_lookup(struct ubifs_info *c, int i)
{
int err, iip;
struct ubifs_nnode *nnode;
if (!c->nroot) {
err = ubifs_read_nnode(c, NULL, 0);
if (err)
return ERR_PTR(err);
}
nnode = c->nroot;
while (1) {
iip = i & (UBIFS_LPT_FANOUT - 1);
i >>= UBIFS_LPT_FANOUT_SHIFT;
if (!i)
break;
nnode = ubifs_get_nnode(c, nnode, iip);
if (IS_ERR(nnode))
return nnode;
}
return nnode;
}
/**
* make_nnode_dirty - find a nnode and, if found, make it dirty.
* @c: UBIFS file-system description object
* @node_num: nnode number of nnode to make dirty
* @lnum: LEB number where nnode was written
* @offs: offset where nnode was written
*
* This function is used by LPT garbage collection. LPT garbage collection is
* used only for the "big" LPT model (c->big_lpt == 1). Garbage collection
* simply involves marking all the nodes in the LEB being garbage-collected as
* dirty. The dirty nodes are written next commit, after which the LEB is free
* to be reused.
*
* This function returns %0 on success and a negative error code on failure.
*/
static int make_nnode_dirty(struct ubifs_info *c, int node_num, int lnum,
int offs)
{
struct ubifs_nnode *nnode;
nnode = nnode_lookup(c, node_num);
if (IS_ERR(nnode))
return PTR_ERR(nnode);
if (nnode->parent) {
struct ubifs_nbranch *branch;
branch = &nnode->parent->nbranch[nnode->iip];
if (branch->lnum != lnum || branch->offs != offs)
return 0; /* nnode is obsolete */
} else if (c->lpt_lnum != lnum || c->lpt_offs != offs)
return 0; /* nnode is obsolete */
/* Assumes cnext list is empty i.e. not called during commit */
if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
c->dirty_nn_cnt += 1;
ubifs_add_nnode_dirt(c, nnode);
/* Mark parent and ancestors dirty too */
nnode = nnode->parent;
while (nnode) {
if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
c->dirty_nn_cnt += 1;
ubifs_add_nnode_dirt(c, nnode);
nnode = nnode->parent;
} else
break;
}
}
return 0;
}
/**
* make_pnode_dirty - find a pnode and, if found, make it dirty.
* @c: UBIFS file-system description object
* @node_num: pnode number of pnode to make dirty
* @lnum: LEB number where pnode was written
* @offs: offset where pnode was written
*
* This function is used by LPT garbage collection. LPT garbage collection is
* used only for the "big" LPT model (c->big_lpt == 1). Garbage collection
* simply involves marking all the nodes in the LEB being garbage-collected as
* dirty. The dirty nodes are written next commit, after which the LEB is free
* to be reused.
*
* This function returns %0 on success and a negative error code on failure.
*/
static int make_pnode_dirty(struct ubifs_info *c, int node_num, int lnum,
int offs)
{
struct ubifs_pnode *pnode;
struct ubifs_nbranch *branch;
pnode = pnode_lookup(c, node_num);
if (IS_ERR(pnode))
return PTR_ERR(pnode);
branch = &pnode->parent->nbranch[pnode->iip];
if (branch->lnum != lnum || branch->offs != offs)
return 0;
do_make_pnode_dirty(c, pnode);
return 0;
}
/**
* make_ltab_dirty - make ltab node dirty.
* @c: UBIFS file-system description object
* @lnum: LEB number where ltab was written
* @offs: offset where ltab was written
*
* This function is used by LPT garbage collection. LPT garbage collection is
* used only for the "big" LPT model (c->big_lpt == 1). Garbage collection
* simply involves marking all the nodes in the LEB being garbage-collected as
* dirty. The dirty nodes are written next commit, after which the LEB is free
* to be reused.
*
* This function returns %0 on success and a negative error code on failure.
*/
static int make_ltab_dirty(struct ubifs_info *c, int lnum, int offs)
{
if (lnum != c->ltab_lnum || offs != c->ltab_offs)
return 0; /* This ltab node is obsolete */
if (!(c->lpt_drty_flgs & LTAB_DIRTY)) {
c->lpt_drty_flgs |= LTAB_DIRTY;
ubifs_add_lpt_dirt(c, c->ltab_lnum, c->ltab_sz);
}
return 0;
}
/**
* make_lsave_dirty - make lsave node dirty.
* @c: UBIFS file-system description object
* @lnum: LEB number where lsave was written
* @offs: offset where lsave was written
*
* This function is used by LPT garbage collection. LPT garbage collection is
* used only for the "big" LPT model (c->big_lpt == 1). Garbage collection
* simply involves marking all the nodes in the LEB being garbage-collected as
* dirty. The dirty nodes are written next commit, after which the LEB is free
* to be reused.
*
* This function returns %0 on success and a negative error code on failure.
*/
static int make_lsave_dirty(struct ubifs_info *c, int lnum, int offs)
{
if (lnum != c->lsave_lnum || offs != c->lsave_offs)
return 0; /* This lsave node is obsolete */
if (!(c->lpt_drty_flgs & LSAVE_DIRTY)) {
c->lpt_drty_flgs |= LSAVE_DIRTY;
ubifs_add_lpt_dirt(c, c->lsave_lnum, c->lsave_sz);
}
return 0;
}
/**
* make_node_dirty - make node dirty.
* @c: UBIFS file-system description object
* @node_type: LPT node type
* @node_num: node number
* @lnum: LEB number where node was written
* @offs: offset where node was written
*
* This function is used by LPT garbage collection. LPT garbage collection is
* used only for the "big" LPT model (c->big_lpt == 1). Garbage collection
* simply involves marking all the nodes in the LEB being garbage-collected as
* dirty. The dirty nodes are written next commit, after which the LEB is free
* to be reused.
*
* This function returns %0 on success and a negative error code on failure.
*/
static int make_node_dirty(struct ubifs_info *c, int node_type, int node_num,
int lnum, int offs)
{
switch (node_type) {
case UBIFS_LPT_NNODE:
return make_nnode_dirty(c, node_num, lnum, offs);
case UBIFS_LPT_PNODE:
return make_pnode_dirty(c, node_num, lnum, offs);
case UBIFS_LPT_LTAB:
return make_ltab_dirty(c, lnum, offs);
case UBIFS_LPT_LSAVE:
return make_lsave_dirty(c, lnum, offs);
}
return -EINVAL;
}
/**
* get_lpt_node_len - return the length of a node based on its type.
* @c: UBIFS file-system description object
* @node_type: LPT node type
*/
static int get_lpt_node_len(struct ubifs_info *c, int node_type)
{
switch (node_type) {
case UBIFS_LPT_NNODE:
return c->nnode_sz;
case UBIFS_LPT_PNODE:
return c->pnode_sz;
case UBIFS_LPT_LTAB:
return c->ltab_sz;
case UBIFS_LPT_LSAVE:
return c->lsave_sz;
}
return 0;
}
/**