--- /dev/null
+/*
+ * 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 TNC functions for committing */
+
+#include <linux/random.h>
+#include "ubifs.h"
+
+/**
+ * make_idx_node - make an index node for fill-the-gaps method of TNC commit.
+ * @c: UBIFS file-system description object
+ * @idx: buffer in which to place new index node
+ * @znode: znode from which to make new index node
+ * @lnum: LEB number where new index node will be written
+ * @offs: offset where new index node will be written
+ * @len: length of new index node
+ */
+static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx,
+ struct ubifs_znode *znode, int lnum, int offs, int len)
+{
+ struct ubifs_znode *zp;
+ int i, err;
+
+ /* Make index node */
+ idx->ch.node_type = UBIFS_IDX_NODE;
+ idx->child_cnt = cpu_to_le16(znode->child_cnt);
+ idx->level = cpu_to_le16(znode->level);
+ for (i = 0; i < znode->child_cnt; i++) {
+ struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
+ struct ubifs_zbranch *zbr = &znode->zbranch[i];
+
+ key_write_idx(c, &zbr->key, &br->key);
+ br->lnum = cpu_to_le32(zbr->lnum);
+ br->offs = cpu_to_le32(zbr->offs);
+ br->len = cpu_to_le32(zbr->len);
+ if (!zbr->lnum || !zbr->len) {
+ ubifs_err(c, "bad ref in znode");
+ ubifs_dump_znode(c, znode);
+ if (zbr->znode)
+ ubifs_dump_znode(c, zbr->znode);
+ }
+ }
+ ubifs_prepare_node(c, idx, len, 0);
+
+ znode->lnum = lnum;
+ znode->offs = offs;
+ znode->len = len;
+
+ err = insert_old_idx_znode(c, znode);
+
+ /* Update the parent */
+ zp = znode->parent;
+ if (zp) {
+ struct ubifs_zbranch *zbr;
+
+ zbr = &zp->zbranch[znode->iip];
+ zbr->lnum = lnum;
+ zbr->offs = offs;
+ zbr->len = len;
+ } else {
+ c->zroot.lnum = lnum;
+ c->zroot.offs = offs;
+ c->zroot.len = len;
+ }
+ c->calc_idx_sz += ALIGN(len, 8);
+
+ atomic_long_dec(&c->dirty_zn_cnt);
+
+ ubifs_assert(ubifs_zn_dirty(znode));
+ ubifs_assert(ubifs_zn_cow(znode));
+
+ /*
+ * Note, unlike 'write_index()' we do not add memory barriers here
+ * because this function is called with @c->tnc_mutex locked.
+ */
+ __clear_bit(DIRTY_ZNODE, &znode->flags);
+ __clear_bit(COW_ZNODE, &znode->flags);
+
+ return err;
+}
+
+/**
+ * fill_gap - make index nodes in gaps in dirty index LEBs.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number that gap appears in
+ * @gap_start: offset of start of gap
+ * @gap_end: offset of end of gap
+ * @dirt: adds dirty space to this
+ *
+ * This function returns the number of index nodes written into the gap.
+ */
+static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end,
+ int *dirt)
+{
+ int len, gap_remains, gap_pos, written, pad_len;
+
+ ubifs_assert((gap_start & 7) == 0);
+ ubifs_assert((gap_end & 7) == 0);
+ ubifs_assert(gap_end >= gap_start);
+
+ gap_remains = gap_end - gap_start;
+ if (!gap_remains)
+ return 0;
+ gap_pos = gap_start;
+ written = 0;
+ while (c->enext) {
+ len = ubifs_idx_node_sz(c, c->enext->child_cnt);
+ if (len < gap_remains) {
+ struct ubifs_znode *znode = c->enext;
+ const int alen = ALIGN(len, 8);
+ int err;
+
+ ubifs_assert(alen <= gap_remains);
+ err = make_idx_node(c, c->ileb_buf + gap_pos, znode,
+ lnum, gap_pos, len);
+ if (err)
+ return err;
+ gap_remains -= alen;
+ gap_pos += alen;
+ c->enext = znode->cnext;
+ if (c->enext == c->cnext)
+ c->enext = NULL;
+ written += 1;
+ } else
+ break;
+ }
+ if (gap_end == c->leb_size) {
+ c->ileb_len = ALIGN(gap_pos, c->min_io_size);
+ /* Pad to end of min_io_size */
+ pad_len = c->ileb_len - gap_pos;
+ } else
+ /* Pad to end of gap */
+ pad_len = gap_remains;
+ dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d",
+ lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len);
+ ubifs_pad(c, c->ileb_buf + gap_pos, pad_len);
+ *dirt += pad_len;
+ return written;
+}
+
+/**
+ * find_old_idx - find an index node obsoleted since the last commit start.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number of obsoleted index node
+ * @offs: offset of obsoleted index node
+ *
+ * Returns %1 if found and %0 otherwise.
+ */
+static int find_old_idx(struct ubifs_info *c, int lnum, int offs)
+{
+ struct ubifs_old_idx *o;
+ struct rb_node *p;
+
+ p = c->old_idx.rb_node;
+ while (p) {
+ o = rb_entry(p, struct ubifs_old_idx, rb);
+ if (lnum < o->lnum)
+ p = p->rb_left;
+ else if (lnum > o->lnum)
+ p = p->rb_right;
+ else if (offs < o->offs)
+ p = p->rb_left;
+ else if (offs > o->offs)
+ p = p->rb_right;
+ else
+ return 1;
+ }
+ return 0;
+}
+
+/**
+ * is_idx_node_in_use - determine if an index node can be overwritten.
+ * @c: UBIFS file-system description object
+ * @key: key of index node
+ * @level: index node level
+ * @lnum: LEB number of index node
+ * @offs: offset of index node
+ *
+ * If @key / @lnum / @offs identify an index node that was not part of the old
+ * index, then this function returns %0 (obsolete). Else if the index node was
+ * part of the old index but is now dirty %1 is returned, else if it is clean %2
+ * is returned. A negative error code is returned on failure.
+ */
+static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
+ int level, int lnum, int offs)
+{
+ int ret;
+
+ ret = is_idx_node_in_tnc(c, key, level, lnum, offs);
+ if (ret < 0)
+ return ret; /* Error code */
+ if (ret == 0)
+ if (find_old_idx(c, lnum, offs))
+ return 1;
+ return ret;
+}
+
+/**
+ * layout_leb_in_gaps - layout index nodes using in-the-gaps method.
+ * @c: UBIFS file-system description object
+ * @p: return LEB number here
+ *
+ * This function lays out new index nodes for dirty znodes using in-the-gaps
+ * method of TNC commit.
+ * This function merely puts the next znode into the next gap, making no attempt
+ * to try to maximise the number of znodes that fit.
+ * This function returns the number of index nodes written into the gaps, or a
+ * negative error code on failure.
+ */
+static int layout_leb_in_gaps(struct ubifs_info *c, int *p)
+{
+ struct ubifs_scan_leb *sleb;
+ struct ubifs_scan_node *snod;
+ int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written;
+
+ tot_written = 0;
+ /* Get an index LEB with lots of obsolete index nodes */
+ lnum = ubifs_find_dirty_idx_leb(c);
+ if (lnum < 0)
+ /*
+ * There also may be dirt in the index head that could be
+ * filled, however we do not check there at present.
+ */
+ return lnum; /* Error code */
+ *p = lnum;
+ dbg_gc("LEB %d", lnum);
+ /*
+ * Scan the index LEB. We use the generic scan for this even though
+ * it is more comprehensive and less efficient than is needed for this
+ * purpose.
+ */
+ sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0);
+ c->ileb_len = 0;
+ if (IS_ERR(sleb))
+ return PTR_ERR(sleb);
+ gap_start = 0;
+ list_for_each_entry(snod, &sleb->nodes, list) {
+ struct ubifs_idx_node *idx;
+ int in_use, level;
+
+ ubifs_assert(snod->type == UBIFS_IDX_NODE);
+ idx = snod->node;
+ key_read(c, ubifs_idx_key(c, idx), &snod->key);
+ level = le16_to_cpu(idx->level);
+ /* Determine if the index node is in use (not obsolete) */
+ in_use = is_idx_node_in_use(c, &snod->key, level, lnum,
+ snod->offs);
+ if (in_use < 0) {
+ ubifs_scan_destroy(sleb);
+ return in_use; /* Error code */
+ }
+ if (in_use) {
+ if (in_use == 1)
+ dirt += ALIGN(snod->len, 8);
+ /*
+ * The obsolete index nodes form gaps that can be
+ * overwritten. This gap has ended because we have
+ * found an index node that is still in use
+ * i.e. not obsolete
+ */
+ gap_end = snod->offs;
+ /* Try to fill gap */
+ written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
+ if (written < 0) {
+ ubifs_scan_destroy(sleb);
+ return written; /* Error code */
+ }
+ tot_written += written;
+ gap_start = ALIGN(snod->offs + snod->len, 8);
+ }
+ }
+ ubifs_scan_destroy(sleb);
+ c->ileb_len = c->leb_size;
+ gap_end = c->leb_size;
+ /* Try to fill gap */
+ written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
+ if (written < 0)
+ return written; /* Error code */
+ tot_written += written;
+ if (tot_written == 0) {
+ struct ubifs_lprops lp;
+
+ dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
+ err = ubifs_read_one_lp(c, lnum, &lp);
+ if (err)
+ return err;
+ if (lp.free == c->leb_size) {
+ /*
+ * We must have snatched this LEB from the idx_gc list
+ * so we need to correct the free and dirty space.
+ */
+ err = ubifs_change_one_lp(c, lnum,
+ c->leb_size - c->ileb_len,
+ dirt, 0, 0, 0);
+ if (err)
+ return err;
+ }
+ return 0;
+ }
+ err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt,
+ 0, 0, 0);
+ if (err)
+ return err;
+ err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len);
+ if (err)
+ return err;
+ dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
+ return tot_written;
+}
+
+/**
+ * get_leb_cnt - calculate the number of empty LEBs needed to commit.
+ * @c: UBIFS file-system description object
+ * @cnt: number of znodes to commit
+ *
+ * This function returns the number of empty LEBs needed to commit @cnt znodes
+ * to the current index head. The number is not exact and may be more than
+ * needed.
+ */
+static int get_leb_cnt(struct ubifs_info *c, int cnt)
+{
+ int d;
+
+ /* Assume maximum index node size (i.e. overestimate space needed) */
+ cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz;
+ if (cnt < 0)
+ cnt = 0;
+ d = c->leb_size / c->max_idx_node_sz;
+ return DIV_ROUND_UP(cnt, d);
+}
+
+/**
+ * layout_in_gaps - in-the-gaps method of committing TNC.
+ * @c: UBIFS file-system description object
+ * @cnt: number of dirty znodes to commit.
+ *
+ * This function lays out new index nodes for dirty znodes using in-the-gaps
+ * method of TNC commit.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int layout_in_gaps(struct ubifs_info *c, int cnt)
+{
+ int err, leb_needed_cnt, written, *p;
+
+ dbg_gc("%d znodes to write", cnt);
+
+ c->gap_lebs = kmalloc(sizeof(int) * (c->lst.idx_lebs + 1), GFP_NOFS);
+ if (!c->gap_lebs)
+ return -ENOMEM;
+
+ p = c->gap_lebs;
+ do {
+ ubifs_assert(p < c->gap_lebs + sizeof(int) * c->lst.idx_lebs);
+ written = layout_leb_in_gaps(c, p);
+ if (written < 0) {
+ err = written;
+ if (err != -ENOSPC) {
+ kfree(c->gap_lebs);
+ c->gap_lebs = NULL;
+ return err;
+ }
+ if (!dbg_is_chk_index(c)) {
+ /*
+ * Do not print scary warnings if the debugging
+ * option which forces in-the-gaps is enabled.
+ */
+ ubifs_warn(c, "out of space");
+ ubifs_dump_budg(c, &c->bi);
+ ubifs_dump_lprops(c);
+ }
+ /* Try to commit anyway */
+ break;
+ }
+ p++;
+ cnt -= written;
+ leb_needed_cnt = get_leb_cnt(c, cnt);
+ dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt,
+ leb_needed_cnt, c->ileb_cnt);
+ } while (leb_needed_cnt > c->ileb_cnt);
+
+ *p = -1;
+ return 0;
+}
+
+/**
+ * layout_in_empty_space - layout index nodes in empty space.
+ * @c: UBIFS file-system description object
+ *
+ * This function lays out new index nodes for dirty znodes using empty LEBs.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int layout_in_empty_space(struct ubifs_info *c)
+{
+ struct ubifs_znode *znode, *cnext, *zp;
+ int lnum, offs, len, next_len, buf_len, buf_offs, used, avail;
+ int wlen, blen, err;
+
+ cnext = c->enext;
+ if (!cnext)
+ return 0;
+
+ lnum = c->ihead_lnum;
+ buf_offs = c->ihead_offs;
+
+ buf_len = ubifs_idx_node_sz(c, c->fanout);
+ buf_len = ALIGN(buf_len, c->min_io_size);
+ used = 0;
+ avail = buf_len;
+
+ /* Ensure there is enough room for first write */
+ next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
+ if (buf_offs + next_len > c->leb_size)
+ lnum = -1;
+
+ while (1) {
+ znode = cnext;
+
+ len = ubifs_idx_node_sz(c, znode->child_cnt);
+
+ /* Determine the index node position */
+ if (lnum == -1) {
+ if (c->ileb_nxt >= c->ileb_cnt) {
+ ubifs_err(c, "out of space");
+ return -ENOSPC;
+ }
+ lnum = c->ilebs[c->ileb_nxt++];
+ buf_offs = 0;
+ used = 0;
+ avail = buf_len;
+ }
+
+ offs = buf_offs + used;
+
+ znode->lnum = lnum;
+ znode->offs = offs;
+ znode->len = len;
+
+ /* Update the parent */
+ zp = znode->parent;
+ if (zp) {
+ struct ubifs_zbranch *zbr;
+ int i;
+
+ i = znode->iip;
+ zbr = &zp->zbranch[i];
+ zbr->lnum = lnum;
+ zbr->offs = offs;
+ zbr->len = len;
+ } else {
+ c->zroot.lnum = lnum;
+ c->zroot.offs = offs;
+ c->zroot.len = len;
+ }
+ c->calc_idx_sz += ALIGN(len, 8);
+
+ /*
+ * Once lprops is updated, we can decrease the dirty znode count
+ * but it is easier to just do it here.
+ */
+ atomic_long_dec(&c->dirty_zn_cnt);
+
+ /*
+ * Calculate the next index node length to see if there is
+ * enough room for it
+ */
+ cnext = znode->cnext;
+ if (cnext == c->cnext)
+ next_len = 0;
+ else
+ next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
+
+ /* Update buffer positions */
+ wlen = used + len;
+ used += ALIGN(len, 8);
+ avail -= ALIGN(len, 8);
+
+ if (next_len != 0 &&
+ buf_offs + used + next_len <= c->leb_size &&
+ avail > 0)
+ continue;
+
+ if (avail <= 0 && next_len &&
+ buf_offs + used + next_len <= c->leb_size)
+ blen = buf_len;
+ else
+ blen = ALIGN(wlen, c->min_io_size);
+
+ /* The buffer is full or there are no more znodes to do */
+ buf_offs += blen;
+ if (next_len) {
+ if (buf_offs + next_len > c->leb_size) {
+ err = ubifs_update_one_lp(c, lnum,
+ c->leb_size - buf_offs, blen - used,
+ 0, 0);
+ if (err)
+ return err;
+ lnum = -1;
+ }
+ used -= blen;
+ if (used < 0)
+ used = 0;
+ avail = buf_len - used;
+ continue;
+ }
+ err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs,
+ blen - used, 0, 0);
+ if (err)
+ return err;
+ break;
+ }
+
+ c->dbg->new_ihead_lnum = lnum;
+ c->dbg->new_ihead_offs = buf_offs;
+
+ return 0;
+}
+
+/**
+ * layout_commit - determine positions of index nodes to commit.
+ * @c: UBIFS file-system description object
+ * @no_space: indicates that insufficient empty LEBs were allocated
+ * @cnt: number of znodes to commit
+ *
+ * Calculate and update the positions of index nodes to commit. If there were
+ * an insufficient number of empty LEBs allocated, then index nodes are placed
+ * into the gaps created by obsolete index nodes in non-empty index LEBs. For
+ * this purpose, an obsolete index node is one that was not in the index as at
+ * the end of the last commit. To write "in-the-gaps" requires that those index
+ * LEBs are updated atomically in-place.
+ */
+static int layout_commit(struct ubifs_info *c, int no_space, int cnt)
+{
+ int err;
+
+ if (no_space) {
+ err = layout_in_gaps(c, cnt);
+ if (err)
+ return err;
+ }
+ err = layout_in_empty_space(c);
+ return err;
+}
+
+/**
+ * find_first_dirty - find first dirty znode.
+ * @znode: znode to begin searching from
+ */
+static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode)
+{
+ int i, cont;
+
+ if (!znode)
+ return NULL;
+
+ while (1) {
+ if (znode->level == 0) {
+ if (ubifs_zn_dirty(znode))
+ return znode;
+ return NULL;
+ }
+ cont = 0;
+ for (i = 0; i < znode->child_cnt; i++) {
+ struct ubifs_zbranch *zbr = &znode->zbranch[i];
+
+ if (zbr->znode && ubifs_zn_dirty(zbr->znode)) {
+ znode = zbr->znode;
+ cont = 1;
+ break;
+ }
+ }
+ if (!cont) {
+ if (ubifs_zn_dirty(znode))
+ return znode;
+ return NULL;
+ }
+ }
+}
+
+/**
+ * find_next_dirty - find next dirty znode.
+ * @znode: znode to begin searching from
+ */
+static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode)
+{
+ int n = znode->iip + 1;
+
+ znode = znode->parent;
+ if (!znode)
+ return NULL;
+ for (; n < znode->child_cnt; n++) {
+ struct ubifs_zbranch *zbr = &znode->zbranch[n];
+
+ if (zbr->znode && ubifs_zn_dirty(zbr->znode))
+ return find_first_dirty(zbr->znode);
+ }
+ return znode;
+}
+
+/**
+ * get_znodes_to_commit - create list of dirty znodes to commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns the number of znodes to commit.
+ */
+static int get_znodes_to_commit(struct ubifs_info *c)
+{
+ struct ubifs_znode *znode, *cnext;
+ int cnt = 0;
+
+ c->cnext = find_first_dirty(c->zroot.znode);
+ znode = c->enext = c->cnext;
+ if (!znode) {
+ dbg_cmt("no znodes to commit");
+ return 0;
+ }
+ cnt += 1;
+ while (1) {
+ ubifs_assert(!ubifs_zn_cow(znode));
+ __set_bit(COW_ZNODE, &znode->flags);
+ znode->alt = 0;
+ cnext = find_next_dirty(znode);
+ if (!cnext) {
+ znode->cnext = c->cnext;
+ break;
+ }
+ znode->cnext = cnext;
+ znode = cnext;
+ cnt += 1;
+ }
+ dbg_cmt("committing %d znodes", cnt);
+ ubifs_assert(cnt == atomic_long_read(&c->dirty_zn_cnt));
+ return cnt;
+}
+
+/**
+ * alloc_idx_lebs - allocate empty LEBs to be used to commit.
+ * @c: UBIFS file-system description object
+ * @cnt: number of znodes to commit
+ *
+ * This function returns %-ENOSPC if it cannot allocate a sufficient number of
+ * empty LEBs. %0 is returned on success, otherwise a negative error code
+ * is returned.
+ */
+static int alloc_idx_lebs(struct ubifs_info *c, int cnt)
+{
+ int i, leb_cnt, lnum;
+
+ c->ileb_cnt = 0;
+ c->ileb_nxt = 0;
+ leb_cnt = get_leb_cnt(c, cnt);
+ dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt);
+ if (!leb_cnt)
+ return 0;
+ c->ilebs = kmalloc(leb_cnt * sizeof(int), GFP_NOFS);
+ if (!c->ilebs)
+ return -ENOMEM;
+ for (i = 0; i < leb_cnt; i++) {
+ lnum = ubifs_find_free_leb_for_idx(c);
+ if (lnum < 0)
+ return lnum;
+ c->ilebs[c->ileb_cnt++] = lnum;
+ dbg_cmt("LEB %d", lnum);
+ }
+ if (dbg_is_chk_index(c) && !(prandom_u32() & 7))
+ return -ENOSPC;
+ return 0;
+}
+
+/**
+ * free_unused_idx_lebs - free unused LEBs that were allocated for the commit.
+ * @c: UBIFS file-system description object
+ *
+ * It is possible that we allocate more empty LEBs for the commit than we need.
+ * This functions frees the surplus.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int free_unused_idx_lebs(struct ubifs_info *c)
+{
+ int i, err = 0, lnum, er;
+
+ for (i = c->ileb_nxt; i < c->ileb_cnt; i++) {
+ lnum = c->ilebs[i];
+ dbg_cmt("LEB %d", lnum);
+ er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
+ LPROPS_INDEX | LPROPS_TAKEN, 0);
+ if (!err)
+ err = er;
+ }
+ return err;
+}
+
+/**
+ * free_idx_lebs - free unused LEBs after commit end.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int free_idx_lebs(struct ubifs_info *c)
+{
+ int err;
+
+ err = free_unused_idx_lebs(c);
+ kfree(c->ilebs);
+ c->ilebs = NULL;
+ return err;
+}
+
+/**
+ * ubifs_tnc_start_commit - start TNC commit.
+ * @c: UBIFS file-system description object
+ * @zroot: new index root position is returned here
+ *
+ * This function prepares the list of indexing nodes to commit and lays out
+ * their positions on flash. If there is not enough free space it uses the
+ * in-gap commit method. Returns zero in case of success and a negative error
+ * code in case of failure.
+ */
+int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot)
+{
+ int err = 0, cnt;
+
+ mutex_lock(&c->tnc_mutex);
+ err = dbg_check_tnc(c, 1);
+ if (err)
+ goto out;
+ cnt = get_znodes_to_commit(c);
+ if (cnt != 0) {
+ int no_space = 0;
+
+ err = alloc_idx_lebs(c, cnt);
+ if (err == -ENOSPC)
+ no_space = 1;
+ else if (err)
+ goto out_free;
+ err = layout_commit(c, no_space, cnt);
+ if (err)
+ goto out_free;
+ ubifs_assert(atomic_long_read(&c->dirty_zn_cnt) == 0);
+ err = free_unused_idx_lebs(c);
+ if (err)
+ goto out;
+ }
+ destroy_old_idx(c);
+ memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch));
+
+ err = ubifs_save_dirty_idx_lnums(c);
+ if (err)
+ goto out;
+
+ spin_lock(&c->space_lock);
+ /*
+ * Although we have not finished committing yet, update size of the
+ * committed index ('c->bi.old_idx_sz') and zero out the index growth
+ * budget. It is OK to do this now, because we've reserved all the
+ * space which is needed to commit the index, and it is save for the
+ * budgeting subsystem to assume the index is already committed,
+ * even though it is not.
+ */
+ ubifs_assert(c->bi.min_idx_lebs == ubifs_calc_min_idx_lebs(c));
+ c->bi.old_idx_sz = c->calc_idx_sz;
+ c->bi.uncommitted_idx = 0;
+ c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
+ spin_unlock(&c->space_lock);
+ mutex_unlock(&c->tnc_mutex);
+
+ dbg_cmt("number of index LEBs %d", c->lst.idx_lebs);
+ dbg_cmt("size of index %llu", c->calc_idx_sz);
+ return err;
+
+out_free:
+ free_idx_lebs(c);
+out:
+ mutex_unlock(&c->tnc_mutex);
+ return err;
+}
+
+/**
+ * write_index - write index nodes.
+ * @c: UBIFS file-system description object
+ *
+ * This function writes the index nodes whose positions were laid out in the
+ * layout_in_empty_space function.
+ */
+static int write_index(struct ubifs_info *c)
+{
+ struct ubifs_idx_node *idx;
+ struct ubifs_znode *znode, *cnext;
+ int i, lnum, offs, len, next_len, buf_len, buf_offs, used;
+ int avail, wlen, err, lnum_pos = 0, blen, nxt_offs;
+
+ cnext = c->enext;
+ if (!cnext)
+ return 0;
+
+ /*
+ * Always write index nodes to the index head so that index nodes and
+ * other types of nodes are never mixed in the same erase block.
+ */
+ lnum = c->ihead_lnum;
+ buf_offs = c->ihead_offs;
+
+ /* Allocate commit buffer */
+ buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size);
+ used = 0;
+ avail = buf_len;
+
+ /* Ensure there is enough room for first write */
+ next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
+ if (buf_offs + next_len > c->leb_size) {
+ err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0,
+ LPROPS_TAKEN);
+ if (err)
+ return err;
+ lnum = -1;
+ }
+
+ while (1) {
+ cond_resched();
+
+ znode = cnext;
+ idx = c->cbuf + used;
+
+ /* Make index node */
+ idx->ch.node_type = UBIFS_IDX_NODE;
+ idx->child_cnt = cpu_to_le16(znode->child_cnt);
+ idx->level = cpu_to_le16(znode->level);
+ for (i = 0; i < znode->child_cnt; i++) {
+ struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
+ struct ubifs_zbranch *zbr = &znode->zbranch[i];
+
+ key_write_idx(c, &zbr->key, &br->key);
+ br->lnum = cpu_to_le32(zbr->lnum);
+ br->offs = cpu_to_le32(zbr->offs);
+ br->len = cpu_to_le32(zbr->len);
+ if (!zbr->lnum || !zbr->len) {
+ ubifs_err(c, "bad ref in znode");
+ ubifs_dump_znode(c, znode);
+ if (zbr->znode)
+ ubifs_dump_znode(c, zbr->znode);
+ }
+ }
+ len = ubifs_idx_node_sz(c, znode->child_cnt);
+ ubifs_prepare_node(c, idx, len, 0);
+
+ /* Determine the index node position */
+ if (lnum == -1) {
+ lnum = c->ilebs[lnum_pos++];
+ buf_offs = 0;
+ used = 0;
+ avail = buf_len;
+ }
+ offs = buf_offs + used;
+
+ if (lnum != znode->lnum || offs != znode->offs ||
+ len != znode->len) {
+ ubifs_err(c, "inconsistent znode posn");
+ return -EINVAL;
+ }
+
+ /* Grab some stuff from znode while we still can */
+ cnext = znode->cnext;
+
+ ubifs_assert(ubifs_zn_dirty(znode));
+ ubifs_assert(ubifs_zn_cow(znode));
+
+ /*
+ * It is important that other threads should see %DIRTY_ZNODE
+ * flag cleared before %COW_ZNODE. Specifically, it matters in
+ * the 'dirty_cow_znode()' function. This is the reason for the
+ * first barrier. Also, we want the bit changes to be seen to
+ * other threads ASAP, to avoid unnecesarry copying, which is
+ * the reason for the second barrier.
+ */
+ clear_bit(DIRTY_ZNODE, &znode->flags);
+ smp_mb__before_atomic();
+ clear_bit(COW_ZNODE, &znode->flags);
+ smp_mb__after_atomic();
+
+ /*
+ * We have marked the znode as clean but have not updated the
+ * @c->clean_zn_cnt counter. If this znode becomes dirty again
+ * before 'free_obsolete_znodes()' is called, then
+ * @c->clean_zn_cnt will be decremented before it gets
+ * incremented (resulting in 2 decrements for the same znode).
+ * This means that @c->clean_zn_cnt may become negative for a
+ * while.
+ *
+ * Q: why we cannot increment @c->clean_zn_cnt?
+ * A: because we do not have the @c->tnc_mutex locked, and the
+ * following code would be racy and buggy:
+ *
+ * if (!ubifs_zn_obsolete(znode)) {
+ * atomic_long_inc(&c->clean_zn_cnt);
+ * atomic_long_inc(&ubifs_clean_zn_cnt);
+ * }
+ *
+ * Thus, we just delay the @c->clean_zn_cnt update until we
+ * have the mutex locked.
+ */
+
+ /* Do not access znode from this point on */
+
+ /* Update buffer positions */
+ wlen = used + len;
+ used += ALIGN(len, 8);
+ avail -= ALIGN(len, 8);
+
+ /*
+ * Calculate the next index node length to see if there is
+ * enough room for it
+ */
+ if (cnext == c->cnext)
+ next_len = 0;
+ else
+ next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
+
+ nxt_offs = buf_offs + used + next_len;
+ if (next_len && nxt_offs <= c->leb_size) {
+ if (avail > 0)
+ continue;
+ else
+ blen = buf_len;
+ } else {
+ wlen = ALIGN(wlen, 8);
+ blen = ALIGN(wlen, c->min_io_size);
+ ubifs_pad(c, c->cbuf + wlen, blen - wlen);
+ }
+
+ /* The buffer is full or there are no more znodes to do */
+ err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, blen);
+ if (err)
+ return err;
+ buf_offs += blen;
+ if (next_len) {
+ if (nxt_offs > c->leb_size) {
+ err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0,
+ 0, LPROPS_TAKEN);
+ if (err)
+ return err;
+ lnum = -1;
+ }
+ used -= blen;
+ if (used < 0)
+ used = 0;
+ avail = buf_len - used;
+ memmove(c->cbuf, c->cbuf + blen, used);
+ continue;
+ }
+ break;
+ }
+
+ if (lnum != c->dbg->new_ihead_lnum ||
+ buf_offs != c->dbg->new_ihead_offs) {
+ ubifs_err(c, "inconsistent ihead");
+ return -EINVAL;
+ }
+
+ c->ihead_lnum = lnum;
+ c->ihead_offs = buf_offs;
+
+ return 0;
+}
+
+/**
+ * free_obsolete_znodes - free obsolete znodes.
+ * @c: UBIFS file-system description object
+ *
+ * At the end of commit end, obsolete znodes are freed.
+ */
+static void free_obsolete_znodes(struct ubifs_info *c)
+{
+ struct ubifs_znode *znode, *cnext;
+
+ cnext = c->cnext;
+ do {
+ znode = cnext;
+ cnext = znode->cnext;
+ if (ubifs_zn_obsolete(znode))
+ kfree(znode);
+ else {
+ znode->cnext = NULL;
+ atomic_long_inc(&c->clean_zn_cnt);
+ atomic_long_inc(&ubifs_clean_zn_cnt);
+ }
+ } while (cnext != c->cnext);
+}
+
+/**
+ * return_gap_lebs - return LEBs used by the in-gap commit method.
+ * @c: UBIFS file-system description object
+ *
+ * This function clears the "taken" flag for the LEBs which were used by the
+ * "commit in-the-gaps" method.
+ */
+static int return_gap_lebs(struct ubifs_info *c)
+{
+ int *p, err;
+
+ if (!c->gap_lebs)
+ return 0;
+
+ dbg_cmt("");
+ for (p = c->gap_lebs; *p != -1; p++) {
+ err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0,
+ LPROPS_TAKEN, 0);
+ if (err)
+ return err;
+ }
+
+ kfree(c->gap_lebs);
+ c->gap_lebs = NULL;
+ return 0;
+}
+
+/**
+ * ubifs_tnc_end_commit - update the TNC for commit end.
+ * @c: UBIFS file-system description object
+ *
+ * Write the dirty znodes.
+ */
+int ubifs_tnc_end_commit(struct ubifs_info *c)
+{
+ int err;
+
+ if (!c->cnext)
+ return 0;
+
+ err = return_gap_lebs(c);
+ if (err)
+ return err;
+
+ err = write_index(c);
+ if (err)
+ return err;
+
+ mutex_lock(&c->tnc_mutex);
+
+ dbg_cmt("TNC height is %d", c->zroot.znode->level + 1);
+
+ free_obsolete_znodes(c);
+
+ c->cnext = NULL;
+ kfree(c->ilebs);
+ c->ilebs = NULL;
+
+ mutex_unlock(&c->tnc_mutex);
+
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff