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28 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* This file is part of UBIFS. |
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* |
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* Copyright (C) 2006-2008 Nokia Corporation. |
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* |
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* Authors: Adrian Hunter |
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* Artem Bityutskiy (Битюцкий Артём) |
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*/ |
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|
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/* This file implements TNC functions for committing */ |
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|
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#include <linux/random.h> |
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#include "ubifs.h" |
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|
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/** |
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* make_idx_node - make an index node for fill-the-gaps method of TNC commit. |
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* @c: UBIFS file-system description object |
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* @idx: buffer in which to place new index node |
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* @znode: znode from which to make new index node |
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* @lnum: LEB number where new index node will be written |
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* @offs: offset where new index node will be written |
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* @len: length of new index node |
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*/ |
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static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx, |
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struct ubifs_znode *znode, int lnum, int offs, int len) |
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{ |
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struct ubifs_znode *zp; |
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u8 hash[UBIFS_HASH_ARR_SZ]; |
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int i, err; |
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/* Make index node */ |
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idx->ch.node_type = UBIFS_IDX_NODE; |
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idx->child_cnt = cpu_to_le16(znode->child_cnt); |
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idx->level = cpu_to_le16(znode->level); |
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for (i = 0; i < znode->child_cnt; i++) { |
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struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); |
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struct ubifs_zbranch *zbr = &znode->zbranch[i]; |
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key_write_idx(c, &zbr->key, &br->key); |
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br->lnum = cpu_to_le32(zbr->lnum); |
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br->offs = cpu_to_le32(zbr->offs); |
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br->len = cpu_to_le32(zbr->len); |
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ubifs_copy_hash(c, zbr->hash, ubifs_branch_hash(c, br)); |
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if (!zbr->lnum || !zbr->len) { |
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ubifs_err(c, "bad ref in znode"); |
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ubifs_dump_znode(c, znode); |
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if (zbr->znode) |
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ubifs_dump_znode(c, zbr->znode); |
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return -EINVAL; |
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} |
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} |
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ubifs_prepare_node(c, idx, len, 0); |
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ubifs_node_calc_hash(c, idx, hash); |
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znode->lnum = lnum; |
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znode->offs = offs; |
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znode->len = len; |
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err = insert_old_idx_znode(c, znode); |
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/* Update the parent */ |
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zp = znode->parent; |
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if (zp) { |
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struct ubifs_zbranch *zbr; |
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zbr = &zp->zbranch[znode->iip]; |
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zbr->lnum = lnum; |
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zbr->offs = offs; |
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zbr->len = len; |
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ubifs_copy_hash(c, hash, zbr->hash); |
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} else { |
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c->zroot.lnum = lnum; |
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c->zroot.offs = offs; |
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c->zroot.len = len; |
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ubifs_copy_hash(c, hash, c->zroot.hash); |
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} |
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c->calc_idx_sz += ALIGN(len, 8); |
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atomic_long_dec(&c->dirty_zn_cnt); |
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ubifs_assert(c, ubifs_zn_dirty(znode)); |
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ubifs_assert(c, ubifs_zn_cow(znode)); |
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/* |
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* Note, unlike 'write_index()' we do not add memory barriers here |
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* because this function is called with @c->tnc_mutex locked. |
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*/ |
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__clear_bit(DIRTY_ZNODE, &znode->flags); |
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__clear_bit(COW_ZNODE, &znode->flags); |
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return err; |
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} |
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/** |
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* fill_gap - make index nodes in gaps in dirty index LEBs. |
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* @c: UBIFS file-system description object |
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* @lnum: LEB number that gap appears in |
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* @gap_start: offset of start of gap |
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* @gap_end: offset of end of gap |
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* @dirt: adds dirty space to this |
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* |
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* This function returns the number of index nodes written into the gap. |
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*/ |
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static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end, |
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int *dirt) |
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{ |
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int len, gap_remains, gap_pos, written, pad_len; |
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ubifs_assert(c, (gap_start & 7) == 0); |
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ubifs_assert(c, (gap_end & 7) == 0); |
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ubifs_assert(c, gap_end >= gap_start); |
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gap_remains = gap_end - gap_start; |
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if (!gap_remains) |
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return 0; |
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gap_pos = gap_start; |
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written = 0; |
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while (c->enext) { |
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len = ubifs_idx_node_sz(c, c->enext->child_cnt); |
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if (len < gap_remains) { |
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struct ubifs_znode *znode = c->enext; |
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const int alen = ALIGN(len, 8); |
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int err; |
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ubifs_assert(c, alen <= gap_remains); |
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err = make_idx_node(c, c->ileb_buf + gap_pos, znode, |
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lnum, gap_pos, len); |
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if (err) |
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return err; |
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gap_remains -= alen; |
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gap_pos += alen; |
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c->enext = znode->cnext; |
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if (c->enext == c->cnext) |
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c->enext = NULL; |
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written += 1; |
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} else |
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break; |
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} |
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if (gap_end == c->leb_size) { |
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c->ileb_len = ALIGN(gap_pos, c->min_io_size); |
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/* Pad to end of min_io_size */ |
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pad_len = c->ileb_len - gap_pos; |
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} else |
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/* Pad to end of gap */ |
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pad_len = gap_remains; |
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dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d", |
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lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len); |
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ubifs_pad(c, c->ileb_buf + gap_pos, pad_len); |
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*dirt += pad_len; |
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return written; |
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} |
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/** |
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* find_old_idx - find an index node obsoleted since the last commit start. |
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* @c: UBIFS file-system description object |
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* @lnum: LEB number of obsoleted index node |
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* @offs: offset of obsoleted index node |
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* |
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* Returns %1 if found and %0 otherwise. |
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*/ |
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static int find_old_idx(struct ubifs_info *c, int lnum, int offs) |
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{ |
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struct ubifs_old_idx *o; |
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struct rb_node *p; |
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p = c->old_idx.rb_node; |
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while (p) { |
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o = rb_entry(p, struct ubifs_old_idx, rb); |
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if (lnum < o->lnum) |
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p = p->rb_left; |
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else if (lnum > o->lnum) |
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p = p->rb_right; |
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else if (offs < o->offs) |
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p = p->rb_left; |
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else if (offs > o->offs) |
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p = p->rb_right; |
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else |
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return 1; |
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} |
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return 0; |
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} |
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/** |
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* is_idx_node_in_use - determine if an index node can be overwritten. |
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* @c: UBIFS file-system description object |
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* @key: key of index node |
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* @level: index node level |
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* @lnum: LEB number of index node |
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* @offs: offset of index node |
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* |
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* If @key / @lnum / @offs identify an index node that was not part of the old |
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* index, then this function returns %0 (obsolete). Else if the index node was |
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* part of the old index but is now dirty %1 is returned, else if it is clean %2 |
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* is returned. A negative error code is returned on failure. |
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*/ |
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static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key, |
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int level, int lnum, int offs) |
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{ |
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int ret; |
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ret = is_idx_node_in_tnc(c, key, level, lnum, offs); |
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if (ret < 0) |
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return ret; /* Error code */ |
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if (ret == 0) |
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if (find_old_idx(c, lnum, offs)) |
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return 1; |
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return ret; |
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} |
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/** |
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* layout_leb_in_gaps - layout index nodes using in-the-gaps method. |
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* @c: UBIFS file-system description object |
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* @p: return LEB number in @c->gap_lebs[p] |
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* |
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* This function lays out new index nodes for dirty znodes using in-the-gaps |
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* method of TNC commit. |
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* This function merely puts the next znode into the next gap, making no attempt |
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* to try to maximise the number of znodes that fit. |
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* This function returns the number of index nodes written into the gaps, or a |
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* negative error code on failure. |
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*/ |
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static int layout_leb_in_gaps(struct ubifs_info *c, int p) |
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{ |
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struct ubifs_scan_leb *sleb; |
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struct ubifs_scan_node *snod; |
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int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written; |
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tot_written = 0; |
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/* Get an index LEB with lots of obsolete index nodes */ |
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lnum = ubifs_find_dirty_idx_leb(c); |
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if (lnum < 0) |
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/* |
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* There also may be dirt in the index head that could be |
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* filled, however we do not check there at present. |
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*/ |
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return lnum; /* Error code */ |
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c->gap_lebs[p] = lnum; |
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dbg_gc("LEB %d", lnum); |
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/* |
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* Scan the index LEB. We use the generic scan for this even though |
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* it is more comprehensive and less efficient than is needed for this |
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* purpose. |
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*/ |
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sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0); |
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c->ileb_len = 0; |
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if (IS_ERR(sleb)) |
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return PTR_ERR(sleb); |
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gap_start = 0; |
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list_for_each_entry(snod, &sleb->nodes, list) { |
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struct ubifs_idx_node *idx; |
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int in_use, level; |
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ubifs_assert(c, snod->type == UBIFS_IDX_NODE); |
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idx = snod->node; |
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key_read(c, ubifs_idx_key(c, idx), &snod->key); |
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level = le16_to_cpu(idx->level); |
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/* Determine if the index node is in use (not obsolete) */ |
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in_use = is_idx_node_in_use(c, &snod->key, level, lnum, |
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snod->offs); |
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if (in_use < 0) { |
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ubifs_scan_destroy(sleb); |
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return in_use; /* Error code */ |
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} |
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if (in_use) { |
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if (in_use == 1) |
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dirt += ALIGN(snod->len, 8); |
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/* |
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* The obsolete index nodes form gaps that can be |
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* overwritten. This gap has ended because we have |
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* found an index node that is still in use |
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* i.e. not obsolete |
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*/ |
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gap_end = snod->offs; |
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/* Try to fill gap */ |
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written = fill_gap(c, lnum, gap_start, gap_end, &dirt); |
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if (written < 0) { |
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ubifs_scan_destroy(sleb); |
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return written; /* Error code */ |
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} |
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tot_written += written; |
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gap_start = ALIGN(snod->offs + snod->len, 8); |
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} |
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} |
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ubifs_scan_destroy(sleb); |
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c->ileb_len = c->leb_size; |
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gap_end = c->leb_size; |
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/* Try to fill gap */ |
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written = fill_gap(c, lnum, gap_start, gap_end, &dirt); |
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if (written < 0) |
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return written; /* Error code */ |
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tot_written += written; |
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if (tot_written == 0) { |
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struct ubifs_lprops lp; |
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dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); |
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err = ubifs_read_one_lp(c, lnum, &lp); |
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if (err) |
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return err; |
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if (lp.free == c->leb_size) { |
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/* |
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* We must have snatched this LEB from the idx_gc list |
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* so we need to correct the free and dirty space. |
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*/ |
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err = ubifs_change_one_lp(c, lnum, |
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c->leb_size - c->ileb_len, |
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dirt, 0, 0, 0); |
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if (err) |
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return err; |
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} |
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return 0; |
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} |
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err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt, |
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0, 0, 0); |
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if (err) |
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return err; |
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err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len); |
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if (err) |
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return err; |
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dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written); |
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return tot_written; |
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} |
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/** |
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* get_leb_cnt - calculate the number of empty LEBs needed to commit. |
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* @c: UBIFS file-system description object |
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* @cnt: number of znodes to commit |
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* |
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* This function returns the number of empty LEBs needed to commit @cnt znodes |
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* to the current index head. The number is not exact and may be more than |
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* needed. |
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*/ |
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static int get_leb_cnt(struct ubifs_info *c, int cnt) |
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{ |
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int d; |
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|
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/* Assume maximum index node size (i.e. overestimate space needed) */ |
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cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz; |
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if (cnt < 0) |
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cnt = 0; |
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d = c->leb_size / c->max_idx_node_sz; |
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return DIV_ROUND_UP(cnt, d); |
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} |
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/** |
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* layout_in_gaps - in-the-gaps method of committing TNC. |
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* @c: UBIFS file-system description object |
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* @cnt: number of dirty znodes to commit. |
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* |
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* This function lays out new index nodes for dirty znodes using in-the-gaps |
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* method of TNC commit. |
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* |
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* This function returns %0 on success and a negative error code on failure. |
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*/ |
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static int layout_in_gaps(struct ubifs_info *c, int cnt) |
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{ |
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int err, leb_needed_cnt, written, p = 0, old_idx_lebs, *gap_lebs; |
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dbg_gc("%d znodes to write", cnt); |
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c->gap_lebs = kmalloc_array(c->lst.idx_lebs + 1, sizeof(int), |
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GFP_NOFS); |
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if (!c->gap_lebs) |
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return -ENOMEM; |
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old_idx_lebs = c->lst.idx_lebs; |
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do { |
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ubifs_assert(c, p < c->lst.idx_lebs); |
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written = layout_leb_in_gaps(c, p); |
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if (written < 0) { |
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err = written; |
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if (err != -ENOSPC) { |
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kfree(c->gap_lebs); |
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c->gap_lebs = NULL; |
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return err; |
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} |
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if (!dbg_is_chk_index(c)) { |
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/* |
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* Do not print scary warnings if the debugging |
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* option which forces in-the-gaps is enabled. |
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*/ |
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ubifs_warn(c, "out of space"); |
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ubifs_dump_budg(c, &c->bi); |
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ubifs_dump_lprops(c); |
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} |
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/* Try to commit anyway */ |
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break; |
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} |
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p++; |
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cnt -= written; |
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leb_needed_cnt = get_leb_cnt(c, cnt); |
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dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt, |
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leb_needed_cnt, c->ileb_cnt); |
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/* |
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* Dynamically change the size of @c->gap_lebs to prevent |
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* oob, because @c->lst.idx_lebs could be increased by |
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* function @get_idx_gc_leb (called by layout_leb_in_gaps-> |
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* ubifs_find_dirty_idx_leb) during loop. Only enlarge |
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* @c->gap_lebs when needed. |
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* |
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*/ |
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if (leb_needed_cnt > c->ileb_cnt && p >= old_idx_lebs && |
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old_idx_lebs < c->lst.idx_lebs) { |
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old_idx_lebs = c->lst.idx_lebs; |
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gap_lebs = krealloc(c->gap_lebs, sizeof(int) * |
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(old_idx_lebs + 1), GFP_NOFS); |
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if (!gap_lebs) { |
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kfree(c->gap_lebs); |
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c->gap_lebs = NULL; |
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return -ENOMEM; |
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} |
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c->gap_lebs = gap_lebs; |
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} |
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} while (leb_needed_cnt > c->ileb_cnt); |
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c->gap_lebs[p] = -1; |
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return 0; |
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} |
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|
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/** |
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* layout_in_empty_space - layout index nodes in empty space. |
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* @c: UBIFS file-system description object |
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* |
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* This function lays out new index nodes for dirty znodes using empty LEBs. |
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* |
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* This function returns %0 on success and a negative error code on failure. |
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*/ |
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static int layout_in_empty_space(struct ubifs_info *c) |
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{ |
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struct ubifs_znode *znode, *cnext, *zp; |
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int lnum, offs, len, next_len, buf_len, buf_offs, used, avail; |
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int wlen, blen, err; |
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cnext = c->enext; |
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if (!cnext) |
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return 0; |
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|
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lnum = c->ihead_lnum; |
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buf_offs = c->ihead_offs; |
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|
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buf_len = ubifs_idx_node_sz(c, c->fanout); |
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buf_len = ALIGN(buf_len, c->min_io_size); |
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used = 0; |
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avail = buf_len; |
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|
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/* Ensure there is enough room for first write */ |
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next_len = ubifs_idx_node_sz(c, cnext->child_cnt); |
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if (buf_offs + next_len > c->leb_size) |
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lnum = -1; |
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|
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while (1) { |
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znode = cnext; |
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|
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len = ubifs_idx_node_sz(c, znode->child_cnt); |
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|
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/* Determine the index node position */ |
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if (lnum == -1) { |
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if (c->ileb_nxt >= c->ileb_cnt) { |
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ubifs_err(c, "out of space"); |
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return -ENOSPC; |
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} |
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lnum = c->ilebs[c->ileb_nxt++]; |
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buf_offs = 0; |
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used = 0; |
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avail = buf_len; |
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} |
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|
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offs = buf_offs + used; |
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|
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znode->lnum = lnum; |
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znode->offs = offs; |
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znode->len = len; |
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|
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/* Update the parent */ |
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zp = znode->parent; |
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if (zp) { |
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struct ubifs_zbranch *zbr; |
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int i; |
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|
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i = znode->iip; |
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zbr = &zp->zbranch[i]; |
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zbr->lnum = lnum; |
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zbr->offs = offs; |
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zbr->len = len; |
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} else { |
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c->zroot.lnum = lnum; |
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c->zroot.offs = offs; |
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c->zroot.len = len; |
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} |
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c->calc_idx_sz += ALIGN(len, 8); |
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|
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/* |
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* Once lprops is updated, we can decrease the dirty znode count |
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* but it is easier to just do it here. |
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*/ |
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atomic_long_dec(&c->dirty_zn_cnt); |
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|
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/* |
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* Calculate the next index node length to see if there is |
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* enough room for it |
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*/ |
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cnext = znode->cnext; |
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if (cnext == c->cnext) |
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next_len = 0; |
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else |
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next_len = ubifs_idx_node_sz(c, cnext->child_cnt); |
|
|
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/* Update buffer positions */ |
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wlen = used + len; |
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used += ALIGN(len, 8); |
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avail -= ALIGN(len, 8); |
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|
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if (next_len != 0 && |
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buf_offs + used + next_len <= c->leb_size && |
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avail > 0) |
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continue; |
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|
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if (avail <= 0 && next_len && |
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buf_offs + used + next_len <= c->leb_size) |
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blen = buf_len; |
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else |
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blen = ALIGN(wlen, c->min_io_size); |
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|
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/* The buffer is full or there are no more znodes to do */ |
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buf_offs += blen; |
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if (next_len) { |
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if (buf_offs + next_len > c->leb_size) { |
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err = ubifs_update_one_lp(c, lnum, |
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c->leb_size - buf_offs, blen - used, |
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0, 0); |
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if (err) |
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return err; |
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lnum = -1; |
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} |
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used -= blen; |
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if (used < 0) |
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used = 0; |
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avail = buf_len - used; |
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continue; |
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} |
|
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(c, !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->cparent = znode->parent; |
|
znode->ciip = znode->iip; |
|
znode->cnext = cnext; |
|
znode = cnext; |
|
cnt += 1; |
|
} |
|
dbg_cmt("committing %d znodes", cnt); |
|
ubifs_assert(c, 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_array(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_max(8)) |
|
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(c, 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, 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) { |
|
u8 hash[UBIFS_HASH_ARR_SZ]; |
|
|
|
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); |
|
ubifs_copy_hash(c, zbr->hash, ubifs_branch_hash(c, br)); |
|
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); |
|
|
|
return -EINVAL; |
|
} |
|
} |
|
len = ubifs_idx_node_sz(c, znode->child_cnt); |
|
ubifs_prepare_node(c, idx, len, 0); |
|
ubifs_node_calc_hash(c, idx, hash); |
|
|
|
mutex_lock(&c->tnc_mutex); |
|
|
|
if (znode->cparent) |
|
ubifs_copy_hash(c, hash, |
|
znode->cparent->zbranch[znode->ciip].hash); |
|
|
|
if (znode->parent) { |
|
if (!ubifs_zn_obsolete(znode)) |
|
ubifs_copy_hash(c, hash, |
|
znode->parent->zbranch[znode->iip].hash); |
|
} else { |
|
ubifs_copy_hash(c, hash, c->zroot.hash); |
|
} |
|
|
|
mutex_unlock(&c->tnc_mutex); |
|
|
|
/* 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(c, ubifs_zn_dirty(znode)); |
|
ubifs_assert(c, 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 unnecessary 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; |
|
}
|
|
|