- 根目录:
- fs
- ubifs
- tnc.c
/*
* 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 (Tree Node Cache) which caches indexing nodes of
* the UBIFS B-tree.
*
* At the moment the locking rules of the TNC tree are quite simple and
* straightforward. We just have a mutex and lock it when we traverse the
* tree. If a znode is not in memory, we read it from flash while still having
* the mutex locked.
*/
#include <linux/crc32.h>
#include <linux/slab.h>
#include "ubifs.h"
/*
* Returned codes of 'matches_name()' and 'fallible_matches_name()' functions.
* @NAME_LESS: name corresponding to the first argument is less than second
* @NAME_MATCHES: names match
* @NAME_GREATER: name corresponding to the second argument is greater than
* first
* @NOT_ON_MEDIA: node referred by zbranch does not exist on the media
*
* These constants were introduce to improve readability.
*/
enum {
NAME_LESS = 0,
NAME_MATCHES = 1,
NAME_GREATER = 2,
NOT_ON_MEDIA = 3,
};
/**
* insert_old_idx - record 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 %0 on success, and a negative error code on failure.
*
* For recovery, there must always be a complete intact version of the index on
* flash at all times. That is called the "old index". It is the index as at the
* time of the last successful commit. Many of the index nodes in the old index
* may be dirty, but they must not be erased until the next successful commit
* (at which point that index becomes the old index).
*
* That means that the garbage collection and the in-the-gaps method of
* committing must be able to determine if an index node is in the old index.
* Most of the old index nodes can be found by looking up the TNC using the
* 'lookup_znode()' function. However, some of the old index nodes may have
* been deleted from the current index or may have been changed so much that
* they cannot be easily found. In those cases, an entry is added to an RB-tree.
* That is what this function does. The RB-tree is ordered by LEB number and
* offset because they uniquely identify the old index node.
*/
static int insert_old_idx(struct ubifs_info *c, int lnum, int offs)
{
struct ubifs_old_idx *old_idx, *o;
struct rb_node **p, *parent = NULL;
old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
if (unlikely(!old_idx))
return -ENOMEM;
old_idx->lnum = lnum;
old_idx->offs = offs;
p = &c->old_idx.rb_node;
while (*p) {
parent = *p;
o = rb_entry(parent, 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 {
ubifs_err("old idx added twice!");
kfree(old_idx);
return 0;
}
}
rb_link_node(&old_idx->rb, parent, p);
rb_insert_color(&old_idx->rb, &c->old_idx);
return 0;
}
/**
* insert_old_idx_znode - record a znode obsoleted since last commit start.
* @c: UBIFS file-system description object
* @znode: znode of obsoleted index node
*
* Returns %0 on success, and a negative error code on failure.
*/
int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode)
{
if (znode->parent) {
struct ubifs_zbranch *zbr;
zbr = &znode->parent->zbranch[znode->iip];
if (zbr->len)
return insert_old_idx(c, zbr->lnum, zbr->offs);
} else
if (c->zroot.len)
return insert_old_idx(c, c->zroot.lnum,
c->zroot.offs);
return 0;
}
/**
* ins_clr_old_idx_znode - record a znode obsoleted since last commit start.
* @c: UBIFS file-system description object
* @znode: znode of obsoleted index node
*
* Returns %0 on success, and a negative error code on failure.
*/
static int ins_clr_old_idx_znode(struct ubifs_info *c,
struct ubifs_znode *znode)
{
int err;
if (znode->parent) {
struct ubifs_zbranch *zbr;
zbr = &znode->parent->zbranch[znode->iip];
if (zbr->len) {
err = insert_old_idx(c, zbr->lnum, zbr->offs);
if (err)
return err;
zbr->lnum = 0;
zbr->offs = 0;
zbr->len = 0;
}
} else
if (c->zroot.len) {
err = insert_old_idx(c, c->zroot.lnum, c->zroot.offs);
if (err)
return err;
c->zroot.lnum = 0;
c->zroot.offs = 0;
c->zroot.len = 0;
}
return 0;
}
/**
* destroy_old_idx - destroy the old_idx RB-tree.
* @c: UBIFS file-system description object
*
* During start commit, the old_idx RB-tree is used to avoid overwriting index
* nodes that were in the index last commit but have since been deleted. This
* is necessary for recovery i.e. the old index must be kept intact until the
* new index is successfully written. The old-idx RB-tree is used for the
* in-the-gaps method of writing index nodes and is destroyed every commit.
*/
void destroy_old_idx(struct ubifs_info *c)
{
struct rb_node *this = c->old_idx.rb_node;
struct ubifs_old_idx *old_idx;
while (this) {
if (this->rb_left) {
this = this->rb_left;
continue;
} else if (this->rb_right) {
this = this->rb_right;
continue;
}
old_idx = rb_entry(this, struct ubifs_old_idx, rb);
this = rb_parent(this);
if (this) {
if (this->rb_left == &old_idx->rb)
this->rb_left = NULL;
else
this->rb_right = NULL;
}
kfree(old_idx);
}
c->old_idx = RB_ROOT;
}
/**
* copy_znode - copy a dirty znode.
* @c: UBIFS file-system description object
* @znode: znode to copy
*
* A dirty znode being committed may not be changed, so it is copied.
*/
static struct ubifs_znode *copy_znode(struct ubifs_info *c,
struct ubifs_znode *znode)
{
struct ubifs_znode *zn;
zn = kmalloc(c->max_znode_sz, GFP_NOFS);
if (unlikely(!zn))
return ERR_PTR(-ENOMEM);
memcpy(zn, znode, c->max_znode_sz);
zn->cnext = NULL;
__set_bit(DIRTY_ZNODE, &zn->flags);
__clear_bit(COW_ZNODE, &zn->flags);
ubifs_assert(!ubifs_zn_obsolete(znode));
__set_bit(OBSOLETE_ZNODE, &znode->flags);
if (znode->level != 0) {
int i;
const int n = zn->child_cnt;
/* The children now have new parent */
for (i = 0; i < n; i++) {
struct ubifs_zbranch *zbr = &zn->zbranch[i];
if (zbr->znode)
zbr->znode->parent = zn;
}
}
atomic_long_inc(&c->dirty_zn_cnt);
return zn;
}
/**
* add_idx_dirt - add dirt due to a dirty znode.
* @c: UBIFS file-system description object
* @lnum: LEB number of index node
* @dirt: size of index node
*
* This function updates lprops dirty space and the new size of the index.
*/
static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
{
c->calc_idx_sz -= ALIGN(dirt, 8);
return ubifs_add_dirt(c, lnum, dirt);
}
/**
* dirty_cow_znode - ensure a znode is not being committed.
* @c: UBIFS file-system description object
* @zbr: branch of znode to check
*
* Returns dirtied znode on success or negative error code on failure.
*/
static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
struct ubifs_zbranch *zbr)
{
struct ubifs_znode *znode = zbr->znode;
struct ubifs_znode *zn;
int err;
if (!ubifs_zn_cow(znode)) {
/* znode is not being committed */
if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
atomic_long_inc(&c->dirty_zn_cnt);
atomic_long_dec(&c->clean_zn_cnt);
atomic_long_dec(&ubifs_clean_zn_cnt);
err = add_idx_dirt(c, zbr->lnum, zbr->len);
if (unlikely(err))
return ERR_PTR(err);
}
return znode;
}
zn = copy_znode(c, znode);
if (IS_ERR(zn))
return zn;
if (zbr->len) {
err = insert_old_idx(c, zbr->lnum, zbr->offs);
if (unlikely(err))
return ERR_PTR(err);
err = add_idx_dirt(c, zbr->lnum, zbr->len);
} else
err = 0;
zbr->znode = zn;
zbr->lnum = 0;
zbr->offs = 0;
zbr->len = 0;
if (unlikely(err))
return ERR_PTR(err);
return zn;
}
/**
* lnc_add - add a leaf node to the leaf node cache.
* @c: UBIFS file-system description object
* @zbr: zbranch of leaf node
* @node: leaf node
*
* Leaf nodes are non-index nodes directory entry nodes or data nodes. The
* purpose of the leaf node cache is to save re-reading the same leaf node over
* and over again. Most things are cached by VFS, however the file system must
* cache directory entries for readdir and for resolving hash collisions. The
* present implementation of the leaf node cache is extremely simple, and
* allows for error returns that are not used but that may be needed if a more
* complex implementation is created.
*
* Note, this function does not add the @node object to LNC directly, but
* allocates a copy of the object and adds the copy to LNC. The reason for this
* is that @node has been allocated outside of the TNC subsystem and will be
* used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC
* may be changed at any time, e.g. freed by the shrinker.
*/
static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
const void *node)
{
int err;
void *lnc_node;
const struct ubifs_dent_node *dent = node;
ubifs_assert(!zbr->leaf);
ubifs_assert(zbr->len != 0);
ubifs_assert(is_hash_key(c, &zbr->key));
err = ubifs_validate_entry(c, dent);
if (err) {
dbg_dump_stack();
dbg_dump_node(c, dent);
return err;
}
lnc_node = kmemdup(node, zbr->len, GFP_NOFS);
if (!lnc_node)
/* We don't have to have the cache, so no error */
return 0;
zbr->leaf = lnc_node;
return 0;
}
/**
* lnc_add_directly - add a leaf node to the leaf-node-cache.
* @c: UBIFS file-system description object
* @zbr: zbranch of leaf node
* @node: leaf node
*
* This function is similar to 'lnc_add()', but it does not create a copy of
* @node but inserts @node to TNC directly.
*/
static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
void *node)
{
int err;
ubifs_assert(!zbr->leaf);
ubifs_assert(zbr->len != 0);
err = ubifs_validate_entry(c, node);
if (err) {
dbg_dump_stack();
dbg_dump_node(c, node);
return err;
}
zbr->leaf = node;
return 0;
}
/**
* lnc_free - remove a leaf node from the leaf node cache.
* @zbr: zbranch of leaf node
* @node: leaf node
*/
static void lnc_free(struct ubifs_zbranch *zbr)
{
if (!zbr->leaf)
return;
kfree(zbr->leaf);
zbr->leaf = NULL;
}
/**
* tnc_read_node_nm - read a "hashed" leaf node.
* @c: UBIFS file-system description object
* @zbr: key and position of the node
* @node: node is returned here
*
* This function reads a "hashed" node defined by @zbr from the leaf node cache
* (in it is there) or from the hash media, in which case the node is also
* added to LNC. Returns zero in case of success or a negative negative error
* code in case of failure.
*/
static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
void *node)
{
int err;
ubifs_assert(is_hash_key(c, &zbr->key));
if (zbr->leaf) {
/* Read from the leaf node cache */
ubifs_assert(zbr->len != 0);
memcpy(node, zbr->leaf, zbr->len);
return 0;
}
err = ubifs_tnc_read_node(c, zbr, node);
if (err)
return err;
/* Add the node to the leaf node cache */
err = lnc_add(c, zbr, node);
return err;
}
/**
* try_read_node - read a node if it is a node.
* @c: UBIFS file-system description object
* @buf: buffer to read to
* @type: node type
* @len: node length (not aligned)
* @lnum: LEB number of node to read
* @offs: offset of node to read
*
* This function tries to read a node of known type and length, checks it and
* stores it in @buf. This function returns %1 if a node is present and %0 if
* a node is not present. A negative error code is returned for I/O errors.
* This function performs that same function as ubifs_read_node except that
* it does not require that there is actually a node present and instead
* the return code indicates if a node was read.
*
* Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
* is true (it is controlled by corresponding mount option). However, if
* @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
* R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
* because during mounting or re-mounting from R/O mode to R/W mode we may read
* journal nodes (when replying the journal or doing the recovery) and the
* journal nodes may potentially be corrupted, so checking is required.
*/
static int try_read_node(const struct ubifs_info *c, void *buf, int type,
int len, int lnum, int offs)
{
int err, node_len;
struct ubifs_ch *ch = buf;
uint32_t crc, node_crc;
dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
err = ubifs_leb_read(c, lnum, buf, offs, len, 1);
if (err) {
ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
type, lnum, offs, err);
return err;
}
if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
return 0;
if (ch->node_type != type)
return 0;
node_len = le32_to_cpu(ch->len);
if (node_len != len)
return 0;
if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
!c->remounting_rw)
return 1;
crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
node_crc = le32_to_cpu(ch->crc);
if (crc != node_crc)
return 0;
return 1;
}
/**
* fallible_read_node - try to read a leaf node.
* @c: UBIFS file-system description object
* @key: key of node to read
* @zbr: position of node
* @node: node returned
*
* This function tries to read a node and returns %1 if the node is read, %0
* if the node is not present, and a negative error code in the case of error.
*/
static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
struct ubifs_zbranch *zbr, void *node)
{
int ret;
dbg_tnck(key, "LEB %d:%d, key ", zbr->lnum, zbr->offs);
ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
zbr->offs);
if (ret == 1) {
union ubifs_key node_key;
struct ubifs_dent_node *dent = node;
/* All nodes have key in the same place */
key_read(c, &dent->key, &node_key);
if (keys_cmp(c, key, &node_key) != 0)
ret = 0;
}
if (ret == 0 && c->replaying)
dbg_mntk(key, "dangling branch LEB %d:%d len %d, key ",
zbr->lnum, zbr->offs, zbr->len);
return ret;
}
/**
* matches_name - determine if a direntry or xattr entry matches a given name.
* @c: UBIFS file-system description object
* @zbr: zbranch of dent
* @nm: name to match
*
* This function checks if xentry/direntry referred by zbranch @zbr matches name
* @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by
* @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case
* of failure, a negative error code is returned.
*/
static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
const struct qstr *nm)
{
struct ubifs_dent_node *dent;
int nlen, err;
/* If possible, match against the dent in the leaf node cache */
if (!zbr->leaf) {
dent = kmalloc(zbr->len, GFP_NOFS);
if (!dent)
return -ENOMEM;
err = ubifs_tnc_read_node(c, zbr, dent);
if (err)
goto out_free;
/* Add the node to the leaf node cache */
err = lnc_add_directly(c, zbr, dent);
if (err)
goto out_free;
} else
dent = zbr->leaf;
nlen = le16_to_cpu(dent->nlen);
err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
if (err == 0) {
if (nlen == nm->len)
return NAME_MATCHES;
else if (nlen < nm->len)
return NAME_LESS;
else
return NAME_GREATER;
} else if (err < 0)
return NAME_LESS;
else
return NAME_GREATER;
out_free:
kfree(dent);
return err;
}
/**
* get_znode - get a TNC znode that may not be loaded yet.
* @c: UBIFS file-system description object
* @znode: parent znode
* @n: znode branch slot number
*
* This function returns the znode or a negative error code.
*/
static struct ubifs_znode *get_znode(struct ubifs_info *c,
struct ubifs_znode *znode, int n)
{
struct ubifs_zbranch *zbr;
zbr = &znode->zbranch[n];
if (zbr->znode)
znode = zbr->znode;
else
znode = ubifs_load_znode(c, zbr, znode, n);
return znode;
}
/**
* tnc_next - find next TNC entry.
* @c: UBIFS file-system description object
* @zn: znode is passed and returned here
* @n: znode branch slot number is passed and returned here
*
* This function returns %0 if the next TNC entry is found, %-ENOENT if there is
* no next entry, or a negative error code otherwise.
*/
static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
{
struct ubifs_znode *znode = *zn;
int nn = *n;
nn += 1;
if (nn < znode->child_cnt) {
*n = nn;
return 0;
}
while (1) {
struct ubifs_znode *zp;
zp = znode->parent;
if (!zp)
return -ENOENT;
nn = znode->iip + 1;
znode = zp;
if (nn < znode->child_cnt) {
znode = get_znode(c, znode, nn);
if (IS_ERR(znode))
return PTR_ERR(znode);
while (znode->level != 0) {
znode = get_znode(c, znode, 0);
if (IS_ERR(znode))
return PTR_ERR(znode);
}
nn = 0;
break;
}
}
*zn = znode;
*n = nn;
return 0;
}
/**
* tnc_prev - find previous TNC entry.
* @c: UBIFS file-system description object
* @zn: znode is returned here
* @n: znode branch slot number is passed and returned here
*
* This function returns %0 if the previous TNC entry is found, %-ENOENT if
* there is no next entry, or a negative error code otherwise.
*/
static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
{
struct ubifs_znode *znode = *zn;
int nn = *n;
if (nn > 0) {
*n = nn - 1;
return 0;
}
while (1) {
struct ubifs_znode *zp;
zp = znode->parent;
if (!zp)
return -ENOENT;
nn = znode->iip - 1;
znode = zp;
if (nn >= 0) {
znode = get_znode(c, znode, nn);
if (IS_ERR(znode))
return PTR_ERR(znode);
while (znode->level != 0) {
nn = znode->child_cnt - 1;
znode = get_znode(c, znode, nn);
if (IS_ERR(znode))
return PTR_ERR(znode);
}
nn = znode->child_cnt - 1;
break;
}
}
*zn = znode;
*n = nn;
return 0;
}
/**
* resolve_collision - resolve a collision.
* @c: UBIFS file-system description object
* @key: key of a directory or extended attribute entry
* @zn: znode is returned here
* @n: zbranch number is passed and returned here
* @nm: name of the entry
*
* This function is called for "hashed" keys to make sure that the found key
* really corresponds to the looked up node (directory or extended attribute
* entry). It returns %1 and sets @zn and @n if the collision is resolved.
* %0 is returned if @nm is not found and @zn and @n are set to the previous
* entry, i.e. to the entry after which @nm could follow if it were in TNC.
* This means that @n may be set to %-1 if the leftmost key in @zn is the
* previous one. A negative error code is returned on failures.
*/
static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
struct ubifs_znode **zn, int *n,
const struct qstr *nm)
{
int err;
err = matches_name(c, &(*zn)->zbranch[*n], nm);
if (unlikely(err < 0))
return err;
if (err == NAME_MATCHES)
return 1;
if (err == NAME_GREATER) {
/* Look left */
while (1) {
err = tnc_prev(c, zn, n);
if (err == -ENOENT) {
ubifs_assert(*n == 0);
*n = -1;
return 0;
}
if (err < 0)
return err;
if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
/*
* We have found the branch after which we would
* like to insert, but inserting in this znode
* may still be wrong. Consider the following 3
* znodes, in the case where we are resolving a
* collision with Key2.
*
* znode zp
* ----------------------
* level 1 | Key0 | Key1 |
* -----------------------
* | |
* znode za | | znode zb
* ------------ ------------
* level 0 | Key0 | | Key2 |
* ------------ ------------
*
* The lookup finds Key2 in znode zb. Lets say
* there is no match and the name is greater so
* we look left. When we find Key0, we end up
* here. If we return now, we will insert into
* znode za at slot n = 1. But that is invalid
* according to the parent's keys. Key2 must
* be inserted into znode zb.
*
* Note, this problem is not relevant for the
* case when we go right, because
* 'tnc_insert()' would correct the parent key.
*/
if (*n == (*zn)->child_cnt - 1) {
err = tnc_next(c, zn, n);
if (err) {
/* Should be impossible */
ubifs_assert(0);
if (err == -ENOENT)
err = -EINVAL;
return err;
}
ubifs_assert(*n == 0);
*n = -1;
}
return 0;
}
err = matches_name(c, &(*zn)->zbranch[*n], nm);
if (err < 0)
return err;
if (err == NAME_LESS)
return 0;
if (err == NAME_MATCHES)
return 1;
ubifs_assert(err == NAME_GREATER);
}
} else {
int nn = *n;
struct ubifs_znode *znode = *zn;
/* Look right */
while (1) {
err = tnc_next(c, &znode, &nn);
if (err == -ENOENT)
return 0;
if (err < 0)
return err;
if (keys_cmp(c, &znode->zbranch[nn].key, key))
return 0;
err = matches_name(c, &znode->zbranch[nn], nm);
if (err < 0)
return err;
if (err == NAME_GREATER)
return 0;
*zn = znode;
*n = nn;
if (err == NAME_MATCHES)
return 1;
ubifs_assert(err == NAME_LESS);
}
}
}
/**
* fallible_matches_name - determine if a dent matches a given name.
* @c: UBIFS file-system description object
* @zbr: zbranch of dent
* @nm: name to match
*
* This is a "fallible" version of 'matches_name()' function which does not
* panic if the direntry/xentry referred by @zbr does not exist on the media.
*
* This function checks if xentry/direntry referred by zbranch @zbr matches name
* @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr
* is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA
* if xentry/direntry referred by @zbr does not exist on the media. A negative
* error code is returned in case of failure.
*/
static int fallible_matches_name(struct ubifs_info *c,
struct ubifs_zbranch *zbr,
const struct qstr *nm)
{
struct ubifs_dent_node *dent;
int nlen, err;
/* If possible, match against the dent in the leaf node cache */
if (!zbr->leaf) {
dent = kmalloc(zbr->len, GFP_NOFS);
if (!dent)
return -ENOMEM;
err = fallible_read_node(c, &zbr->key, zbr, dent);
if (err < 0)
goto out_free;
if (err == 0) {
/* The node was not present */
err = NOT_ON_MEDIA;
goto out_free;
}
ubifs_assert(err == 1);
err = lnc_add_directly(c, zbr, dent);
if (err)
goto out_free;
} else
dent = zbr->leaf;
nlen = le16_to_cpu(dent->nlen);
err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
if (err == 0) {
if (nlen == nm->len)
return NAME_MATCHES;
else if (nlen < nm->len)
return NAME_LESS;
else
return NAME_GREATER;
} else if (err < 0)
return NAME_LESS;
else
return NAME_GREATER;
out_free:
kfree(dent);
return err;
}
/**
* fallible_resolve_collision - resolve a collision even if nodes are missing.
* @c: UBIFS file-system description object
* @key: key
* @zn: znode is returned here
* @n: branch number is passed and returned here
* @nm: name of directory entry
* @adding: indicates caller is adding a key to the TNC
*
* This is a "fallible" version of the 'resolve_collision()' function which
* does not panic if one of the nodes referred to by TNC does not exist on the
* media. This may happen when replaying the journal if a deleted node was
* Garbage-collected and the commit was not done. A branch that refers to a node
* that is not present is called a dangling branch. The following are the return
* codes for this function:
* o if @nm was found, %1 is returned and @zn and @n are set to the found
* branch;
* o if we are @adding and @nm was not found, %0 is returned;
* o if we are not @adding and @nm was not found, but a dangling branch was
* found, then %1 is returned and @zn and @n are set to the dangling branch;
* o a negative error code is returned in case of failure.
*/
static int fallible_resolve_collision(struct ubifs_info *c,
const union ubifs_key *key,
struct ubifs_znode **zn, int *n,
const struct qstr *nm, int adding)
{
struct ubifs_znode *o_znode = NULL, *znode = *zn;
int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n;
cmp = fallible_matches_name(c, &znode->zbranch[nn], nm);
if (unlikely(cmp < 0))
return cmp;
if (cmp == NAME_MATCHES)
return 1;
if (cmp == NOT_ON_MEDIA) {
o_znode = znode;
o_n = nn;
/*
* We are unlucky and hit a dangling branch straight away.
* Now we do not really know where to go to find the needed
* branch - to the left or to the right. Well, let's try left.
*/
unsure = 1;
} else if (!adding)
unsure = 1; /* Remove a dangling branch wherever it is */
if (cmp == NAME_GREATER || unsure) {
/* Look left */
while (1) {
err = tnc_prev(c, zn, n);
if (err == -ENOENT) {
ubifs_assert(*n == 0);
*n = -1;
break;
}
if (err < 0)
return err;
if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
/* See comments in 'resolve_collision()' */
if (*n == (*zn)->child_cnt - 1) {
err = tnc_next(c, zn, n);
if (err) {
/* Should be impossible */
ubifs_assert(0);
if (err == -ENOENT)
err = -EINVAL;
return err;
}
ubifs_assert(*n == 0);
*n = -1;
}
break;
}
err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm);
if (err < 0)
return err;
if (err == NAME_MATCHES)
return 1;
if (err == NOT_ON_MEDIA) {
o_znode = *zn;
o_n = *n;
continue;
}
if (!adding)
continue;
if (err == NAME_LESS)
break;
else
unsure = 0;
}
}
if (cmp == NAME_LESS || unsure) {
/* Look right */
*zn = znode;
*n = nn;
while (1) {
err = tnc_next(c, &znode, &nn);
if (err == -ENOENT)
break;
if (err < 0)
return err;
if (keys_cmp(c, &znode->zbranch[nn].key, key))
break;
err = fallible_matches_name(c, &znode->zbranch[nn], nm);
if (err < 0)
return err;
if (err == NAME_GREATER)
break;
*zn = znode;
*n = nn;
if (err == NAME_MATCHES)
return 1;
if (err == NOT_ON_MEDIA) {
o_znode = znode;
o_n = nn;
}
}
}
/* Never match a dangling branch when adding */
if (adding || !o_znode)
return 0;
dbg_mntk(key, "dangling match LEB %d:%d len %d key ",
o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
o_znode->zbranch[o_n].len);
*zn = o_znode;
*n = o_n;
return 1;
}
/**
* matches_position - determine if a zbranch matches a given position.
* @zbr: zbranch of dent
* @lnum: LEB number of dent to match
* @offs: offset of dent to match
*
* This function returns %1 if @lnum:@offs matches, and %0 otherwise.
*/
static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
{
if (zbr->lnum == lnum && zbr->offs == offs)
return 1;
else
return 0;
}
/**
* resolve_collision_directly - resolve a collision directly.
* @c: UBIFS file-system description object
* @key: key of directory entry
* @zn: znode is passed and returned here
* @n: zbranch number is passed and returned here
* @lnum: LEB number of dent node to match
* @offs: offset of dent node to match
*
* This function is used for "hashed" keys to make sure the found directory or
* extended attribute entry node is what was looked for. It is used when the
* flash address of the right node is known (@lnum:@offs) which makes it much
* easier to resolve collisions (no need to read entries and match full
* names). This function returns %1 and sets @zn and @n if the collision is
* resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the
* previous directory entry. Otherwise a negative error code is returned.
*/
static int resolve_collision_directly(struct ubifs_info *c,
const union ubifs_key *key,
struct ubifs_znode **zn, int *n,
int lnum, int offs)
{
struct ubifs_znode *znode;
int nn, err;
znode = *zn;
nn = *n;
if (matches_position(&znode->zbranch[nn], lnum, offs))
return 1;
/* Look left */
while (1) {
err = tnc_prev(c, &znode, &nn);
if (err == -ENOENT)
break;
if (err < 0)
return err;
if (keys_cmp(c, &znode->zbranch[nn].key, key))
break;
if (matches_position(&znode->zbranch[nn], lnum, offs)) {
*zn = znode;
*n = nn;
return 1;
}
}
/* Look right */
znode = *zn;
nn = *n;
while (1) {
err = tnc_next(c, &znode, &nn);
if (err == -ENOENT)
return 0;
if (err < 0)
return err;
if (keys_cmp(c, &znode->zbranch[nn].key, key))
return 0;
*zn = znode;
*n = nn;
if (matches_position(&znode->zbranch[nn], lnum, offs))
return 1;
}
}
/**
* dirty_cow_bottom_up - dirty a znode and its ancestors.
* @c: UBIFS file-system description object
* @znode: znode to dirty
*
* If we do not have a unique key that resides in a znode, then we cannot
* dirty that znode from the top down (i.e. by using lookup_level0_dirty)
* This function records the path back to the last dirty ancestor, and then
* dirties the znodes on that path.
*/
static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
struct ubifs_znode *znode)
{
struct ubifs_znode *zp;
int *path = c->bottom_up_buf, p = 0;
ubifs_assert(c->zroot.znode);
ubifs_assert(znode);
if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
kfree(c->bottom_up_buf);
c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int),
GFP_NOFS);
if (!c->bottom_up_buf)
return ERR_PTR(-ENOMEM);
path = c->bottom_up_buf;
}
if (c->zroot.znode->level) {
/* Go up until parent is dirty */
while (1) {
int n;
zp = znode->parent;
if (!zp)
break;
n = znode->iip;
ubifs_assert(p < c->zroot.znode->level);
path[p++] = n;
if (!zp->cnext && ubifs_zn_dirty(znode))
break;
znode = zp;
}
}
/* Come back down, dirtying as we go */
while (1) {
struct ubifs_zbranch *zbr;
zp = znode->parent;
if (zp) {
ubifs_assert(path[p - 1] >= 0);
ubifs_assert(path[p - 1] < zp->child_cnt);
zbr = &zp->zbranch[path[--p]];
znode = dirty_cow_znode(c, zbr);
} else {
ubifs_assert(znode == c->zroot.znode);
znode = dirty_cow_znode(c, &c->zroot);
}
if (IS_ERR(znode) || !p)
break;
ubifs_assert(path[p - 1] >= 0);
ubifs_assert(path[p - 1] < znode->child_cnt);
znode = znode->zbranch[path[p - 1]].znode;
}
return znode;
}
/**
* ubifs_lookup_level0 - search for zero-level znode.
* @c: UBIFS file-system description object
* @key: key to lookup
* @zn: znode is returned here
* @n: znode branch slot number is returned here
*
* This function looks up the TNC tree and search for zero-level znode which
* refers key @key. The found zero-level znode is returned in @zn. There are 3
* cases:
* o exact match, i.e. the found zero-level znode contains key @key, then %1
* is returned and slot number of the matched branch is stored in @n;
* o not exact match, which means that zero-level znode does not contain
* @key, then %0 is returned and slot number of the closest branch is stored
* in @n;
* o @key is so small that it is even less than the lowest key of the
* leftmost zero-level node, then %0 is returned and %0 is stored in @n.
*
* Note, when the TNC tree is traversed, some znodes may be absent, then this
* function reads corresponding indexing nodes and inserts them to TNC. In
* case of failure, a negative error code is returned.
*/
int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
struct ubifs_znode **zn, int *n)
{
int err, exact;
struct ubifs_znode *znode;
unsigned long time = get_seconds();
dbg_tnck(key, "search key ");
ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
znode = c->zroot.znode;
if (unlikely(!znode)) {
znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
if (IS_ERR(znode))
return PTR_ERR(znode);
}
znode->time = time;
while (1) {
struct ubifs_zbranch *zbr;
exact = ubifs_search_zbranch(c, znode, key, n);
if (znode->level == 0)
break;
if (*n < 0)
*n = 0;
zbr = &znode->zbranch[*n];
if (zbr->znode) {
znode->time = time;
znode = zbr->znode;
continue;
}
/* znode is not in TNC cache, load it from the media */
znode = ubifs_load_znode(c, zbr, znode, *n);
if (IS_ERR(znode))
return PTR_ERR(znode);
}
*zn = znode;
if (exact || !is_hash_key(c, key) || *n != -1) {
dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
return exact;
}
/*
* Here is a tricky place. We have not found the key and this is a
* "hashed" key, which may collide. The rest of the code deals with
* situations like this:
*
* | 3 | 5 |
* / \
* | 3 | 5 | | 6 | 7 | (x)
*
* Or more a complex example:
*
* | 1 | 5 |
* / \
* | 1 | 3 | | 5 | 8 |
* \ /
* | 5 | 5 | | 6 | 7 | (x)
*
* In the examples, if we are looking for key "5", we may reach nodes
* marked with "(x)". In this case what we have do is to look at the
* left and see if there is "5" key there. If there is, we have to
* return it.
*
* Note, this whole situation is possible because we allow to have
* elements which are equivalent to the next key in the parent in the
* children of current znode. For example, this happens if we split a
* znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something
* like this:
* | 3 | 5 |
* / \
* | 3 | 5 | | 5 | 6 | 7 |
* ^
* And this becomes what is at the first "picture" after key "5" marked
* with "^" is removed. What could be done is we could prohibit
* splitting in the middle of the colliding sequence. Also, when
* removing the leftmost key, we would have to correct the key of the
* parent node, which would introduce additional complications. Namely,
* if we changed the leftmost key of the parent znode, the garbage
* collector would be unable to find it (GC is doing this when GC'ing
* indexing LEBs). Although we already have an additional RB-tree where
* we save such changed znodes (see 'ins_clr_old_idx_znode()') until
* after the commit. But anyway, this does not look easy to implement
* so we did not try this.
*/
err = tnc_prev(c, &znode, n);
if (err == -ENOENT) {
dbg_tnc("found 0, lvl %d, n -1", znode->level);
*n = -1;
return 0;
}
if (unlikely(err < 0))
return err;
if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
dbg_tnc("found 0, lvl %d, n -1", znode->level);
*n = -1;
return 0;
}
dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
*zn = znode;
return 1;
}
/**
* lookup_level0_dirty - search for zero-level znode dirtying.
* @c: UBIFS file-system description object
* @key: key to lookup
* @zn: znode is returned here
* @n: znode branch slot number is returned here
*
* This function looks up the TNC tree and search for zero-level znode which
* refers key @key. The found zero-level znode is returned in @zn. There are 3
* cases:
* o exact match, i.e. the found zero-level znode contains key @key, then %1
* is returned and slot number of the matched branch is stored in @n;
* o not exact match, which means that zero-level znode does not contain @key
* then %0 is returned and slot number of the closed branch is stored in
* @n;
* o @key is so small that it is even less than the lowest key of the
* leftmost zero-level node, then %0 is returned and %-1 is stored in @n.
*
* Additionally all znodes in the path from the root to the located zero-level
* znode are marked as dirty.
*
* Note, when the TNC tree is traversed, some znodes may be absent, then this
* function reads corresponding indexing nodes and inserts them to TNC. In
* case of failure, a negative error code is returned.
*/
static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
struct ubifs_znode **zn, int *n)
{
int err, exact;
struct ubifs_znode *znode;
unsigned long time = get_seconds();
dbg_tnck(key, "search and dirty key ");
znode = c->zroot.znode;
if (unlikely(!znode)) {
znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
if (IS_ERR(znode))
return PTR_ERR(znode);
}
znode = dirty_cow_znode(c, &c->zroot);
if (IS_ERR(znode))
return PTR_ERR(znode);
znode->time = time;
while (1) {
struct ubifs_zbranch *zbr;
exact = ubifs_search_zbranch(c, znode, key, n);
if (znode->level == 0)
break;
if (*n < 0)
*n = 0;
zbr = &znode->zbranch[*n];
if (zbr->znode) {
znode->time = time;
znode = dirty_cow_znode(c, zbr);
if (IS_ERR(znode))
return PTR_ERR(znode);
continue;
}
/* znode is not in TNC cache, load it from the media */
znode = ubifs_load_znode(c, zbr, znode, *n);
if (IS_ERR(znode))
return PTR_ERR(znode);
znode = dirty_cow_znode(c, zbr);
if (IS_ERR(znode))
return PTR_ERR(znode);
}
*zn = znode;
if (exact || !is_hash_key(c, key) || *n != -1) {
dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
return exact;
}
/*
* See huge comment at 'lookup_level0_dirty()' what is the rest of the
* code.
*/
err = tnc_prev(c, &znode, n);
if (err == -ENOENT) {
*n = -1;
dbg_tnc("found 0, lvl %d, n -1", znode->level);
return 0;
}
if (unlikely(err < 0))
return err;
if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
*n = -1;
dbg_tnc("found 0, lvl %d, n -1", znode->level);
return 0;
}
if (znode->cnext || !ubifs_zn_dirty(znode)) {
znode = dirty_cow_bottom_up(c, znode);
if (IS_ERR(znode))
return PTR_ERR(znode);
}
dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
*zn = znode;
return 1;
}
/**
* maybe_leb_gced - determine if a LEB may have been garbage collected.
* @c: UBIFS file-system description object
* @lnum: LEB number
* @gc_seq1: garbage collection sequence number
*
* This function determines if @lnum may have been garbage collected since
* sequence number @gc_seq1. If it may have been then %1 is returned, otherwise
* %0 is returned.
*/
static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
{
int gc_seq2, gced_lnum;
gced_lnum = c->gced_lnum;
smp_rmb();
gc_seq2 = c->gc_seq;
/* Same seq means no GC */
if (gc_seq1 == gc_seq2)
return 0;
/* Different by more than 1 means we don't know */
if (gc_seq1 + 1 != gc_seq2)
return 1;
/*
* We have seen the sequence number has increased by 1. Now we need to
* be sure we read the right LEB number, so read it again.
*/
smp_rmb();
if (gced_lnum != c->gced_lnum)
return 1;
/* Finally we can check lnum */
if (gced_lnum == lnum)
return 1;
return 0;
}
/**
* ubifs_tnc_locate - look up a file-system node and return it and its location.
* @c: UBIFS file-system description object
* @key: node key to lookup
* @node: the node is returned here
* @lnum: LEB number is returned here
* @offs: offset is returned here
*
* This function looks up and reads node with key @key. The caller has to make
* sure the @node buffer is large enough to fit the node. Returns zero in case
* of success, %-ENOENT if the node was not found, and a negative error code in
* case of failure. The node location can be returned in @lnum and @offs.
*/
int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
void *node, int *lnum, int *offs)
{
int found, n, err, safely = 0, gc_seq1;
struct ubifs_znode *znode;
struct ubifs_zbranch zbr, *zt;
again:
mutex_lock(&c->tnc_mutex);
found = ubifs_lookup_level0(c, key, &znode, &n);
if (!found) {
err = -ENOENT;
goto out;
} else if (found < 0) {
err = found;
goto out;
}
zt = &znode->zbranch[n];
if (lnum) {
*lnum = zt->lnum;
*offs = zt->offs;
}
if (is_hash_key(c, key)) {
/*
* In this case the leaf node cache gets used, so we pass the
* address of the zbranch and keep the mutex locked
*/
err = tnc_read_node_nm(c, zt, node);
goto out;
}
if (safely) {
err = ubifs_tnc_read_node(c, zt, node);
goto out;
}
/* Drop the TNC mutex prematurely and race with garbage collection */
zbr = znode->zbranch[n];
gc_seq1 = c->gc_seq;
mutex_unlock(&c->tnc_mutex);
if (ubifs_get_wbuf(c, zbr.lnum)) {
/* We do not GC journal heads */
err = ubifs_tnc_read_node(c, &zbr, node);
return err;
}
err = fallible_read_node(c, key, &zbr, node);
if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
/*
* The node may have been GC'ed out from under us so try again
* while keeping the TNC mutex locked.
*/
safely = 1;
goto again;
}
return 0;
out:
mutex_unlock(&c->tnc_mutex);
return err;
}
/**
* ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
* @c: UBIFS file-system description object
* @bu: bulk-read parameters and results
*
* Lookup consecutive data node keys for the same inode that reside
* consecutively in the same LEB. This function returns zero in case of success
* and a negative error code in case of failure.
*
* Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
* makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
* maximum possible amount of nodes for bulk-read.
*/
int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
{
int n, err = 0, lnum = -1, uninitialized_var(offs);
int uninitialized_var(len);
unsigned int block = key_block(c, &bu->key);
struct ubifs_znode *znode;
bu->cnt = 0;
bu->blk_cnt = 0;
bu->eof = 0;
mutex_lock(&c->tnc_mutex);
/* Find first key */
err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
if (err < 0)
goto out;
if (err) {
/* Key found */
len = znode->zbranch[n].len;
/* The buffer must be big enough for at least 1 node */
if (len > bu->buf_len) {
err = -EINVAL;
goto out;
}
/* Add this key */
bu->zbranch[bu->cnt++] = znode->zbranch[n];
bu->blk_cnt += 1;
lnum = znode->zbranch[n].lnum;
offs = ALIGN(znode->zbranch[n].offs + len, 8);
}
while (1) {
struct ubifs_zbranch *zbr;
union ubifs_key *key;
unsigned int next_block;
/* Find next key */
err = tnc_next(c, &znode, &n);
if (err)
goto out;
zbr = &znode->zbranch[n];
key = &zbr->key;
/* See if there is another data key for this file */
if (key_inum(c, key) != key_inum(c, &bu->key) ||
key_type(c, key) != UBIFS_DATA_KEY) {
err = -ENOENT;
goto out;
}
if (lnum < 0) {
/* First key found */
lnum = zbr->lnum;
offs = ALIGN(zbr->offs + zbr->len, 8);
len = zbr->len;
if (len > bu->buf_len) {
err = -EINVAL;
goto out;
}
} else {
/*
* The data nodes must be in consecutive positions in
* the same LEB.
*/
if (zbr->lnum != lnum || zbr->offs != offs)
goto out;
offs += ALIGN(zbr->len, 8);
len = ALIGN(len, 8) + zbr->len;
/* Must not exceed buffer length */
if (len > bu->buf_len)
goto out;
}
/* Allow for holes */
next_block = key_block(c, key);
bu->blk_cnt += (next_block - block - 1);
if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
goto out;
block = next_block;
/* Add this key */
bu->zbranch[bu->cnt++] = *zbr;
bu->blk_cnt += 1;
/* See if we have room for more */
if (bu->cnt >= UBIFS_MAX_BULK_READ)
goto out;
if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
goto out;
}
out:
if (err == -ENOENT) {
bu->eof = 1;
err = 0;
}
bu->gc_seq = c->gc_seq;
mutex_unlock(&c->tnc_mutex);
if (err)
return err;
/*
* An enormous hole could cause bulk-read to encompass too many
* page cache pages, so limit the number here.
*/
if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
bu->blk_cnt = UBIFS_MAX_BULK_READ;
/*
* Ensure that bulk-read covers a whole number of page cache
* pages.
*/
if (UBIFS_BLOCKS_PER_PAGE == 1 ||
!(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
return 0;
if (bu->eof) {
/* At the end of file we can round up */
bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
return 0;
}
/* Exclude data nodes that do not make up a whole page cache page */
block = key_block(c, &bu->key) + bu->blk_cnt;
block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
while (bu->cnt) {
if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
break;
bu->cnt -= 1;
}
return 0;
}
/**
* read_wbuf - bulk-read from a LEB with a wbuf.
* @wbuf: wbuf that may overlap the read
* @buf: buffer into which to read
* @len: read length
* @lnum: LEB number from which to read
* @offs: offset from which to read
*
* This functions returns %0 on success or a negative error code on failure.
*/
static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
int offs)
{
const struct ubifs_info *c = wbuf->c;
int rlen, overlap;
dbg_io("LEB %d:%d, length %d", lnum, offs, len);
ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
ubifs_assert(!(offs & 7) && offs < c->leb_size);
ubifs_assert(offs + len <= c->leb_size);
spin_lock(&wbuf->lock);
overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
if (!overlap) {
/* We may safely unlock the write-buffer and read the data */
spin_unlock(&wbuf->lock);
return ubifs_leb_read(c, lnum, buf, offs, len, 0);
}
/* Don't read under wbuf */
rlen = wbuf->offs - offs;
if (rlen < 0)
rlen = 0;
/* Copy the rest from the write-buffer */
memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
spin_unlock(&wbuf->lock);
if (rlen > 0)
/* Read everything that goes before write-buffer */
return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
return 0;
}
/**
* validate_data_node - validate data nodes for bulk-read.
* @c: UBIFS file-system description object
* @buf: buffer containing data node to validate
* @zbr: zbranch of data node to validate
*
* This functions returns %0 on success or a negative error code on failure.
*/
static int validate_data_node(struct ubifs_info *c, void *buf,
struct ubifs_zbranch *zbr)
{
union ubifs_key key1;
struct ubifs_ch *ch = buf;
int err, len;
if (ch->node_type != UBIFS_DATA_NODE) {
ubifs_err("bad node type (%d but expected %d)",
ch->node_type, UBIFS_DATA_NODE);
goto out_err;
}
err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
if (err) {
ubifs_err("expected node type %d", UBIFS_DATA_NODE);
goto out;
}
len = le32_to_cpu(ch->len);
if (len != zbr->len) {
ubifs_err("bad node length %d, expected %d", len, zbr->len);
goto out_err;
}
/* Make sure the key of the read node is correct */
key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
if (!keys_eq(c, &zbr->key, &key1)) {
ubifs_err("bad key in node at LEB %d:%d",
zbr->lnum, zbr->offs);
dbg_tnck(&zbr->key, "looked for key ");
dbg_tnck(&key1, "found node's key ");
goto out_err;
}
return 0;
out_err:
err = -EINVAL;
out:
ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
dbg_dump_node(c, buf);
dbg_dump_stack();
return err;
}
/**
* ubifs_tnc_bulk_read - read a number of data nodes in one go.
* @c: UBIFS file-system description object
* @bu: bulk-read parameters and results
*
* This functions reads and validates the data nodes that were identified by the
* 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
* -EAGAIN to indicate a race with GC, or another negative error code on
* failure.
*/
int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
{
int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
struct ubifs_wbuf *wbuf;
void *buf;
len = bu->zbranch[bu->cnt - 1].offs;
len += bu->zbranch[bu->cnt - 1].len - offs;
if (len > bu->buf_len) {
ubifs_err("buffer too small %d vs %d", bu->buf_len, len);
return -EINVAL;
}
/* Do the read */
wbuf = ubifs_get_wbuf(c, lnum);
if (wbuf)
err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
else
err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
/* Check for a race with GC */
if (maybe_leb_gced(c, lnum, bu->gc_seq))
return -EAGAIN;
if (err && err != -EBADMSG) {
ubifs_err("failed to read from LEB %d:%d, error %d",
lnum, offs, err);
dbg_dump_stack();
dbg_tnck(&bu->key, "key ");
return err;
}
/* Validate the nodes read */
buf = bu->buf;
for (i = 0; i < bu->cnt; i++) {
err = validate_data_node(c, buf, &bu->zbranch[i]);
if (err)
return err;
buf = buf + ALIGN(bu->zbranch[i].len, 8);
}
return 0;
}
/**
* do_lookup_nm- look up a "hashed" node.
* @c: UBIFS file-system description object
* @key: node key to lookup
* @node: the node is returned here
* @nm: node name
*
* This function look up and reads a node which contains name hash in the key.
* Since the hash may have collisions, there may be many nodes with the same
* key, so we have to sequentially look to all of them until the needed one is
* found. This function returns zero in case of success, %-ENOENT if the node
* was not found, and a negative error code in case of failure.
*/
static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
void *node, const struct qstr *nm)
{
int found, n, err;
struct ubifs_znode *znode;
dbg_tnck(key, "name '%.*s' key ", nm->len, nm->name);
mutex_lock(&c->tnc_mutex);
found = ubifs_lookup_level0(c, key, &znode, &n);
if (!found) {
err = -ENOENT;
goto out_unlock;
} else if (found < 0) {
err = found;
goto out_unlock;
}
ubifs_assert(n >= 0);
err = resolve_collision(c, key, &znode, &n, nm);
dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
if (unlikely(err < 0))
goto out_unlock;
if (err == 0) {
err = -ENOENT;
goto out_unlock;
}
err = tnc_read_node_nm(c, &znode->zbranch[n], node);
out_unlock:
mutex_unlock(&c->tnc_mutex);
return err;
}
/**
* ubifs_tnc_lookup_nm - look up a "hashed" node.
* @c: UBIFS file-system description object
* @key: node key to lookup
* @node: the node is returned here
* @nm: node name
*
* This function look up and reads a node which contains name hash in the key.
* Since the hash may have collisions, there may be many nodes with the same
* key, so we have to sequentially look to all of them until the needed one is
* found. This function returns zero in case of success, %-ENOENT if the node
* was not found, and a negative error code in case of failure.
*/
int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
void *node, const struct qstr *nm)
{
int err, len;
const struct ubifs_dent_node *dent = node;
/*
* We assume that in most of the cases there are no name collisions and
* 'ubifs_tnc_lookup()' returns us the right direntry.
*/
err = ubifs_tnc_lookup(c, key, node);
if (err)
return err;
len = le16_to_cpu(dent->nlen);
if (nm->len == len && !memcmp(dent->name, nm->name, len))
return 0;
/*
* Unluckily, there are hash collisions and we have to iterate over
* them look at each direntry with colliding name hash sequentially.
*/
return do_lookup_nm(c, key, node, nm);
}
/**
* correct_parent_keys - correct parent znodes' keys.
* @c: UBIFS file-system description object
* @znode: znode to correct parent znodes for
*
* This is a helper function for 'tnc_insert()'. When the key of the leftmost
* zbranch changes, keys of parent znodes have to be corrected. This helper
* function is called in such situations and corrects the keys if needed.
*/
static void correct_parent_keys(const struct ubifs_info *c,
struct ubifs_znode *znode)
{
union ubifs_key *key, *key1;
ubifs_assert(znode->parent);
ubifs_assert(znode->iip == 0);
key = &znode->zbranch[0].key;
key1 = &znode->parent->zbranch[0].key;
while (keys_cmp(c, key, key1) < 0) {
key_copy(c, key, key1);
znode = znode->parent;
znode->alt = 1;
if (!znode->parent || znode->iip)
break;
key1 = &znode->parent->zbranch[0].key;
}
}
/**
* insert_zbranch - insert a zbranch into a znode.
* @znode: znode into which to insert
* @zbr: zbranch to insert
* @n: slot number to insert to
*
* This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
* znode's array of zbranches and keeps zbranches consolidated, so when a new
* zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
* slot, zbranches starting from @n have to be moved right.
*/
static void insert_zbranch(struct ubifs_znode *znode,
const struct ubifs_zbranch *zbr, int n)
{
int i;
ubifs_assert(ubifs_zn_dirty(znode));
if (znode->level) {
for (i = znode->child_cnt; i > n; i--) {
znode->zbranch[i] = znode->zbranch[i - 1];
if (znode->zbranch[i].znode)
znode->zbranch[i].znode->iip = i;
}
if (zbr->znode)
zbr->znode->iip = n;
} else
for (i = znode->child_cnt; i > n; i--)
znode->zbranch[i] = znode->zbranch[i - 1];
znode->zbranch[n] = *zbr;
znode->child_cnt += 1;
/*
* After inserting at slot zero, the lower bound of the key range of
* this znode may have changed. If this znode is subsequently split
* then the upper bound of the key range may change, and furthermore
* it could change to be lower than the original lower bound. If that
* happens, then it will no longer be possible to find this znode in the
* TNC using the key from the index node on flash. That is bad because
* if it is not found, we will assume it is obsolete and may overwrite
* it. Then if there is an unclean unmount, we will start using the
* old index which will be broken.
*
* So we first mark znodes that have insertions at slot zero, and then
* if they are split we add their lnum/offs to the old_idx tree.
*/
if (n == 0)
znode->alt = 1;
}
/**
* tnc_insert - insert a node into TNC.
* @c: UBIFS file-system description object
* @znode: znode to insert into
* @zbr: branch to insert
* @n: slot number to insert new zbranch to
*
* This function inserts a new node described by @zbr into znode @znode. If
* znode does not have a free slot for new zbranch, it is split. Parent znodes
* are splat as well if needed. Returns zero in case of success or a negative
* error code in case of failure.
*/
static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
struct ubifs_zbranch *zbr, int n)
{
struct ubifs_znode *zn, *zi, *zp;
int i, keep, move, appending = 0;
union ubifs_key *key = &zbr->key, *key1;
ubifs_assert(n >= 0 && n <= c->fanout);
/* Implement naive insert for now */
again:
zp = znode->parent;
if (znode->child_cnt < c->fanout) {
ubifs_assert(n != c->fanout);
dbg_tnck(key, "inserted at %d level %d, key ", n, znode->level);
insert_zbranch(znode, zbr, n);
/* Ensure parent's key is correct */
if (n == 0 && zp && znode->iip == 0)
correct_parent_keys(c, znode);
return 0;
}
/*
* Unfortunately, @znode does not have more empty slots and we have to
* split it.
*/
dbg_tnck(key, "splitting level %d, key ", znode->level);
if (znode->alt)
/*
* We can no longer be sure of finding this znode by key, so we
* record it in the old_idx tree.
*/
ins_clr_old_idx_znode(c, znode);
zn = kzalloc(c->max_znode_sz, GFP_NOFS);
if (!zn)
return -ENOMEM;
zn->parent = zp;
zn->level = znode->level;
/* Decide where to split */
if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
/* Try not to split consecutive data keys */
if (n == c->fanout) {
key1 = &znode->zbranch[n - 1].key;
if (key_inum(c, key1) == key_inum(c, key) &&
key_type(c, key1) == UBIFS_DATA_KEY)
appending = 1;
} else
goto check_split;
} else if (appending && n != c->fanout) {
/* Try not to split consecutive data keys */
appending = 0;
check_split:
if (n >= (c->fanout + 1) / 2) {
key1 = &znode->zbranch[0].key;
if (key_inum(c, key1) == key_inum(c, key) &&
key_type(c, key1) == UBIFS_DATA_KEY) {
key1 = &znode->zbranch[n].key;
if (key_inum(c, key1) != key_inum(c, key) ||
key_type(c, key1) != UBIFS_DATA_KEY) {
keep = n;
move = c->fanout - keep;
zi = znode;
goto do_split;
}
}
}
}
if (appending) {
keep = c->fanout;
move = 0;
} else {
keep = (c->fanout + 1) / 2;
move = c->fanout - keep;
}
/*
* Although we don't at present, we could look at the neighbors and see
* if we can move some zbranches there.
*/
if (n < keep) {
/* Insert into existing znode */
zi = znode;
move += 1;
keep -= 1;
} else {
/* Insert into new znode */
zi = zn;
n -= keep;
/* Re-parent */
if (zn->level != 0)
zbr->znode->parent = zn;
}
do_split:
__set_bit(DIRTY_ZNODE, &zn->flags);
atomic_long_inc(&c->dirty_zn_cnt);
zn->child_cnt = move;
znode->child_cnt = keep;
dbg_tnc("moving %d, keeping %d", move, keep);
/* Move zbranch */
for (i = 0; i < move; i++) {
zn->zbranch[i] = znode->zbranch[keep + i];
/* Re-parent */
if (zn->level != 0)
if (zn->zbranch[i].znode) {
zn->zbranch[i].znode->parent = zn;
zn->zbranch[i].znode->iip = i;
}
}
/* Insert new key and branch */
dbg_tnck(key, "inserting at %d level %d, key ", n, zn->level);
insert_zbranch(zi, zbr, n);
/* Insert new znode (produced by spitting) into the parent */
if (zp) {
if (n == 0 && zi == znode && znode->iip == 0)
correct_parent_keys(c, znode);
/* Locate insertion point */
n = znode->iip + 1;
/* Tail recursion */
zbr->key = zn->zbranch[0].key;
zbr->znode = zn;
zbr->lnum = 0;
zbr->offs = 0;
zbr->len = 0;
znode = zp;
goto again;
}
/* We have to split root znode */
dbg_tnc("creating new zroot at level %d", znode->level + 1);
zi = kzalloc(c->max_znode_sz, GFP_NOFS);
if (!zi)
return -ENOMEM;
zi->child_cnt = 2;
zi->level = znode->level + 1;
__set_bit(DIRTY_ZNODE, &zi->flags);
atomic_long_inc(&c->dirty_zn_cnt);
zi->zbranch[0].key = znode->zbranch[0].key;
zi->zbranch[0].znode = znode;
zi->zbranch[0].lnum = c->zroot.lnum;
zi->zbranch[0].offs = c->zroot.offs;
zi->zbranch[0].len = c->zroot.len;
zi->zbranch[1].key = zn->zbranch[0].key;
zi->zbranch[1].znode = zn;
c->zroot.lnum = 0;
c->zroot.offs = 0;
c->zroot.len = 0;
c->zroot.znode = zi;
zn->parent = zi;
zn->iip = 1;
znode->parent = zi;
znode->iip = 0;
return 0;
}
/**
* ubifs_tnc_add - add a node to TNC.
* @c: UBIFS file-system description object
* @key: key to add
* @lnum: LEB number of node
* @offs: node offset
* @len: node length
*
* This function adds a node with key @key to TNC. The node may be new or it may
* obsolete some existing one. Returns %0 on success or negative error code on
* failure.
*/
int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
int offs, int len)
{
int found, n, err = 0;
struct ubifs_znode *znode;
mutex_lock(&c->tnc_mutex);
dbg_tnck(key, "%d:%d, len %d, key ", lnum, offs, len);
found = lookup_level0_dirty(c, key, &znode, &n);
if (!found) {
struct ubifs_zbranch zbr;
zbr.znode = NULL;
zbr.lnum = lnum;
zbr.offs = offs;
zbr.len = len;
key_copy(c, key, &zbr.key);
err = tnc_insert(c, znode, &zbr, n + 1);
} else if (found == 1) {
struct ubifs_zbranch *zbr = &znode->zbranch[n];
lnc_free(zbr);
err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
zbr->lnum = lnum;
zbr->offs = offs;
zbr->len = len;
} else
err = found;
if (!err)
err = dbg_check_tnc(c, 0);
mutex_unlock(&c->tnc_mutex);
return err;
}
/**
* ubifs_tnc_replace - replace a node in the TNC only if the old node is found.
* @c: UBIFS file-system description object
* @key: key to add
* @old_lnum: LEB number of old node
* @old_offs: old node offset
* @lnum: LEB number of node
* @offs: node offset
* @len: node length
*
* This function replaces a node with key @key in the TNC only if the old node
* is found. This function is called by garbage collection when node are moved.
* Returns %0 on success or negative error code on failure.
*/
int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
int old_lnum, int old_offs, int lnum, int offs, int len)
{
int found, n, err = 0;
struct ubifs_znode *znode;
mutex_lock(&c->tnc_mutex);
dbg_tnck(key, "old LEB %d:%d, new LEB %d:%d, len %d, key ", old_lnum,
old_offs, lnum, offs, len);
found = lookup_level0_dirty(c, key, &znode, &n);
if (found < 0) {
err = found;
goto out_unlock;
}
if (found == 1) {
struct ubifs_zbranch *zbr = &znode->zbranch[n];
found = 0;
if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
lnc_free(zbr);
err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
if (err)
goto out_unlock;
zbr->lnum = lnum;
zbr->offs = offs;
zbr->len = len;
found = 1;
} else if (is_hash_key(c, key)) {
found = resolve_collision_directly(c, key, &znode, &n,
old_lnum, old_offs);
dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
found, znode, n, old_lnum, old_offs);
if (found < 0) {
err = found;
goto out_unlock;
}
if (found) {
/* Ensure the znode is dirtied */
if (znode->cnext || !ubifs_zn_dirty(znode)) {
znode = dirty_cow_bottom_up(c, znode);
if (IS_ERR(znode)) {
err = PTR_ERR(znode);
goto out_unlock;
}
}
zbr = &znode->zbranch[n];
lnc_free(zbr);
err = ubifs_add_dirt(c, zbr->lnum,
zbr->len);
if (err)
goto out_unlock;
zbr->lnum = lnum;
zbr->offs = offs;
zbr->len = len;
}
}
}
if (!found)
err = ubifs_add_dirt(c, lnum, len);
if (!err)
err = dbg_check_tnc(c, 0);
out_unlock:
mutex_unlock(&c->tnc_mutex);
return err;
}
/**
* ubifs_tnc_add_nm - add a "hashed" node to TNC.
* @c: UBIFS file-system description object
* @key: key to add
* @lnum: LEB number of node
* @offs: node offset
* @len: node length
* @nm: node name
*
* This is the same as 'ubifs_tnc_add()' but it should be used with keys which
* may have collisions, like directory entry keys.
*/
int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
int lnum, int offs, int len, const struct qstr *nm)
{
int found, n, err = 0;
struct ubifs_znode *znode;
mutex_lock(&c->tnc_mutex);
dbg_tnck(key, "LEB %d:%d, name '%.*s', key ",
lnum, offs, nm->len, nm->name);
found = lookup_level0_dirty(c, key, &znode, &n);
if (found < 0) {
err = found;
goto out_unlock;
}
if (found == 1) {
if (c->replaying)
found = fallible_resolve_collision(c, key, &znode, &n,
nm, 1);
else
found = resolve_collision(c, key, &znode, &n, nm);
dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n);
if (found < 0) {
err = found;
goto out_unlock;
}
/* Ensure the znode is dirtied */
if (znode->cnext || !ubifs_zn_dirty(znode)) {
znode = dirty_cow_bottom_up(c, znode);
if (IS_ERR(znode)) {
err = PTR_ERR(znode);
goto out_unlock;
}
}
if (found == 1) {
struct ubifs_zbranch *zbr = &znode->zbranch[n];
lnc_free(zbr);
err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
zbr->lnum = lnum;
zbr->offs = offs;
zbr->len = len;
goto out_unlock;
}
}
if (!found) {
struct ubifs_zbranch zbr;
zbr.znode = NULL;
zbr.lnum = lnum;
zbr.offs = offs;
zbr.len = len;
key_copy(c, key, &zbr.key);
err = tnc_insert(c, znode, &zbr, n + 1);
if (err)
goto out_unlock;
if (c->replaying) {
/*
* We did not find it in the index so there may be a
* dangling branch still in the index. So we remove it
* by passing 'ubifs_tnc_remove_nm()' the same key but
* an unmatchable name.
*/
struct qstr noname = { .len = 0, .name = "" };
err = dbg_check_tnc(c, 0);
mutex_unlock(&c->tnc_mutex);
if (err)
return err;
return ubifs_tnc_remove_nm(c, key, &noname);
}
}
out_unlock:
if (!err)
err = dbg_check_tnc(c, 0);
mutex_unlock(&c->tnc_mutex);
return err;
}
/**
* tnc_delete - delete a znode form TNC.
* @c: UBIFS file-system description object
* @znode: znode to delete from
* @n: zbranch slot number to delete
*
* This function deletes a leaf node from @n-th slot of @znode. Returns zero in
* case of success and a negative error code in case of failure.
*/
static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
{
struct ubifs_zbranch *zbr;
struct ubifs_znode *zp;
int i, err;
/* Delete without merge for now */
ubifs_assert(znode->level == 0);
ubifs_assert(n >= 0 && n < c->fanout);
dbg_tnck(&znode->zbranch[n].key, "deleting key ");
zbr = &znode->zbranch[n];
lnc_free(zbr);
err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
if (err) {
dbg_dump_znode(c, znode);
return err;
}
/* We do not "gap" zbranch slots */
for (i = n; i < znode->child_cnt - 1; i++)
znode->zbranch[i] = znode->zbranch[i + 1];
znode->child_cnt -= 1;
if (znode->child_cnt > 0)
return 0;
/*
* This was the last zbranch, we have to delete this znode from the
* parent.
*/
do {
ubifs_assert(!ubifs_zn_obsolete(znode));
ubifs_assert(ubifs_zn_dirty(znode));
zp = znode->parent;
n = znode->iip;
atomic_long_dec(&c->dirty_zn_cnt);
err = insert_old_idx_znode(c, znode);
if (err)
return err;
if (znode->cnext) {
__set_bit(OBSOLETE_ZNODE, &znode->flags);
atomic_long_inc(&c->clean_zn_cnt);
atomic_long_inc(&ubifs_clean_zn_cnt);
} else
kfree(znode);
znode = zp;
} while (znode->child_cnt == 1); /* while removing last child */
/* Remove from znode, entry n - 1 */
znode->child_cnt -= 1;
ubifs_assert(znode->level != 0);
for (i = n; i < znode->child_cnt; i++) {
znode->zbranch[i] = znode->zbranch[i + 1];
if (znode->zbranch[i].znode)
znode->zbranch[i].znode->iip = i;
}
/*
* If this is the root and it has only 1 child then
* collapse the tree.
*/
if (!znode->parent) {
while (znode->child_cnt == 1 && znode->level != 0) {
zp = znode;
zbr = &znode->zbranch[0];
znode = get_znode(c, znode, 0);
if (IS_ERR(znode))
return PTR_ERR(znode);
znode = dirty_cow_znode(c, zbr);
if (IS_ERR(znode))
return PTR_ERR(znode);
znode->parent = NULL;
znode->iip = 0;
if (c->zroot.len) {
err = insert_old_idx(c, c->zroot.lnum,
c->zroot.offs);
if (err)
return err;
}
c->zroot.lnum = zbr->lnum;
c->zroot.offs = zbr->offs;
c->zroot.len = zbr->len;
c->zroot.znode = znode;
ubifs_assert(!ubifs_zn_obsolete(zp));
ubifs_assert(ubifs_zn_dirty(zp));
atomic_long_dec(&c->dirty_zn_cnt);
if (zp->cnext) {
__set_bit(OBSOLETE_ZNODE, &zp->flags);
atomic_long_inc(&c->clean_zn_cnt);
atomic_long_inc(&ubifs_clean_zn_cnt);
} else
kfree(zp);
}
}
return 0;
}
/**
* ubifs_tnc_remove - remove an index entry of a node.
* @c: UBIFS file-system description object
* @key: key of node
*
* Returns %0 on success or negative error code on failure.
*/
int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
{
int found, n, err = 0;
struct ubifs_znode *znode;
mutex_lock(&c->tnc_mutex);
dbg_tnck(key, "key ");
found = lookup_level0_dirty(c, key, &znode, &n);
if (found < 0) {
err = found;
goto out_unlock;
}
if (found == 1)
err = tnc_delete(c, znode, n);
if (!err)
err = dbg_check_tnc(c, 0);
out_unlock:
mutex_unlock(&c->tnc_mutex);
return err;
}
/**
* ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
* @c: UBIFS file-system description object
* @key: key of node
* @nm: directory entry name
*
* Returns %0 on success or negative error code on failure.
*/
int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
const struct qstr *nm)
{
int n, err;
struct ubifs_znode *znode;
mutex_lock(&c->tnc_mutex);
dbg_tnck(key, "%.*s, key ", nm->len, nm->name);
err = lookup_level0_dirty(c, key, &znode, &n);
if (err < 0)
goto out_unlock;
if (err) {
if (c->replaying)
err = fallible_resolve_collision(c, key, &znode, &n,
nm, 0);
else
err = resolve_collision(c, key, &znode, &n, nm);
dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
if (err < 0)
goto out_unlock;
if (err) {
/* Ensure the znode is dirtied */
if (znode->cnext || !ubifs_zn_dirty(znode)) {
znode = dirty_cow_bottom_up(c, znode);
if (IS_ERR(znode)) {
err = PTR_ERR(znode);
goto out_unlock;
}
}
err = tnc_delete(c, znode, n);
}
}
out_unlock:
if (!err)
err = dbg_check_tnc(c, 0);
mutex_unlock(&c->tnc_mutex);
return err;
}
/**
* key_in_range - determine if a key falls within a range of keys.
* @c: UBIFS file-system description object
* @key: key to check
* @from_key: lowest key in range
* @to_key: highest key in range
*
* This function returns %1 if the key is in range and %0 otherwise.
*/
static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
union ubifs_key *from_key, union ubifs_key *to_key)
{
if (keys_cmp(c, key, from_key) < 0)
return 0;
if (keys_cmp(c, key, to_key) > 0)
return 0;
return 1;
}
/**
* ubifs_tnc_remove_range - remove index entries in range.
* @c: UBIFS file-system description object
* @from_key: lowest key to remove
* @to_key: highest key to remove
*
* This function removes index entries starting at @from_key and ending at
* @to_key. This function returns zero in case of success and a negative error
* code in case of failure.
*/
int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
union ubifs_key *to_key)
{
int i, n, k, err = 0;
struct ubifs_znode *znode;
union ubifs_key *key;
mutex_lock(&c->tnc_mutex);
while (1) {
/* Find first level 0 znode that contains keys to remove */
err = ubifs_lookup_level0(c, from_key, &znode, &n);
if (err < 0)
goto out_unlock;
if (err)
key = from_key;
else {
err = tnc_next(c, &znode, &n);
if (err == -ENOENT) {
err = 0;
goto out_unlock;
}
if (err < 0)
goto out_unlock;
key = &znode->zbranch[n].key;
if (!key_in_range(c, key, from_key, to_key)) {
err = 0;
goto out_unlock;
}
}
/* Ensure the znode is dirtied */
if (znode->cnext || !ubifs_zn_dirty(znode)) {
znode = dirty_cow_bottom_up(c, znode);
if (IS_ERR(znode)) {
err = PTR_ERR(znode);
goto out_unlock;
}
}
/* Remove all keys in range except the first */
for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
key = &znode->zbranch[i].key;
if (!key_in_range(c, key, from_key, to_key))
break;
lnc_free(&znode->zbranch[i]);
err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
znode->zbranch[i].len);
if (err) {
dbg_dump_znode(c, znode);
goto out_unlock;
}
dbg_tnck(key, "removing key ");
}
if (k) {
for (i = n + 1 + k; i < znode->child_cnt; i++)
znode->zbranch[i - k] = znode->zbranch[i];
znode->child_cnt -= k;
}
/* Now delete the first */
err = tnc_delete(c, znode, n);
if (err)
goto out_unlock;
}
out_unlock:
if (!err)
err = dbg_check_tnc(c, 0);
mutex_unlock(&c->tnc_mutex);
return err;
}
/**
* ubifs_tnc_remove_ino - remove an inode from TNC.
* @c: UBIFS file-system description object
* @inum: inode number to remove
*
* This function remove inode @inum and all the extended attributes associated
* with the anode from TNC and returns zero in case of success or a negative
* error code in case of failure.
*/
int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
{
union ubifs_key key1, key2;
struct ubifs_dent_node *xent, *pxent = NULL;
struct qstr nm = { .name = NULL };
dbg_tnc("ino %lu", (unsigned long)inum);
/*
* Walk all extended attribute entries and remove them together with
* corresponding extended attribute inodes.
*/
lowest_xent_key(c, &key1, inum);
while (1) {
ino_t xattr_inum;
int err;
xent = ubifs_tnc_next_ent(c, &key1, &nm);
if (IS_ERR(xent)) {
err = PTR_ERR(xent);
if (err == -ENOENT)
break;
return err;
}
xattr_inum = le64_to_cpu(xent->inum);
dbg_tnc("xent '%s', ino %lu", xent->name,
(unsigned long)xattr_inum);
nm.name = xent->name;
nm.len = le16_to_cpu(xent->nlen);
err = ubifs_tnc_remove_nm(c, &key1, &nm);
if (err) {
kfree(xent);
return err;
}
lowest_ino_key(c, &key1, xattr_inum);
highest_ino_key(c, &key2, xattr_inum);
err = ubifs_tnc_remove_range(c, &key1, &key2);
if (err) {
kfree(xent);
return err;
}
kfree(pxent);
pxent = xent;
key_read(c, &xent->key, &key1);
}
kfree(pxent);
lowest_ino_key(c, &key1, inum);
highest_ino_key(c, &key2, inum);
return ubifs_tnc_remove_range(c, &key1, &key2);
}
/**
* ubifs_tnc_next_ent - walk directory or extended attribute entries.
* @c: UBIFS file-system description object
* @key: key of last entry
* @nm: name of last entry found or %NULL
*
* This function finds and reads the next directory or extended attribute entry
* after the given key (@key) if there is one. @nm is used to resolve
* collisions.
*
* If the name of the current entry is not known and only the key is known,
* @nm->name has to be %NULL. In this case the semantics of this function is a
* little bit different and it returns the entry corresponding to this key, not
* the next one. If the key was not found, the closest "right" entry is
* returned.
*
* If the fist entry has to be found, @key has to contain the lowest possible
* key value for this inode and @name has to be %NULL.
*
* This function returns the found directory or extended attribute entry node
* in case of success, %-ENOENT is returned if no entry was found, and a
* negative error code is returned in case of failure.
*/
struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
union ubifs_key *key,
const struct qstr *nm)
{
int n, err, type = key_type(c, key);
struct ubifs_znode *znode;
struct ubifs_dent_node *dent;
struct ubifs_zbranch *zbr;
union ubifs_key *dkey;
dbg_tnck(key, "%s ", nm->name ? (char *)nm->name : "(lowest)");
ubifs_assert(is_hash_key(c, key));
mutex_lock(&c->tnc_mutex);
err = ubifs_lookup_level0(c, key, &znode, &n);
if (unlikely(err < 0))
goto out_unlock;
if (nm->name) {
if (err) {
/* Handle collisions */
err = resolve_collision(c, key, &znode, &n, nm);
dbg_tnc("rc returned %d, znode %p, n %d",
err, znode, n);
if (unlikely(err < 0))
goto out_unlock;
}
/* Now find next entry */
err = tnc_next(c, &znode, &n);
if (unlikely(err))
goto out_unlock;
} else {
/*
* The full name of the entry was not given, in which case the
* behavior of this function is a little different and it
* returns current entry, not the next one.
*/
if (!err) {
/*
* However, the given key does not exist in the TNC
* tree and @znode/@n variables contain the closest
* "preceding" element. Switch to the next one.
*/
err = tnc_next(c, &znode, &n);
if (err)
goto out_unlock;
}
}
zbr = &znode->zbranch[n];
dent = kmalloc(zbr->len, GFP_NOFS);
if (unlikely(!dent)) {
err = -ENOMEM;
goto out_unlock;
}
/*
* The above 'tnc_next()' call could lead us to the next inode, check
* this.
*/
dkey = &zbr->key;
if (key_inum(c, dkey) != key_inum(c, key) ||
key_type(c, dkey) != type) {
err = -ENOENT;
goto out_free;
}
err = tnc_read_node_nm(c, zbr, dent);
if (unlikely(err))
goto out_free;
mutex_unlock(&c->tnc_mutex);
return dent;
out_free:
kfree(dent);
out_unlock:
mutex_unlock(&c->tnc_mutex);
return ERR_PTR(err);
}
/**
* tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
* @c: UBIFS file-system description object
*
* Destroy left-over obsolete znodes from a failed commit.
*/
static void tnc_destroy_cnext(struct ubifs_info *c)
{
struct ubifs_znode *cnext;
if (!c->cnext)
return;
ubifs_assert(c->cmt_state == COMMIT_BROKEN);
cnext = c->cnext;
do {
struct ubifs_znode *znode = cnext;
cnext = cnext->cnext;
if (ubifs_zn_obsolete(znode))
kfree(znode);
} while (cnext && cnext != c->cnext);
}
/**
* ubifs_tnc_close - close TNC subsystem and free all related resources.
* @c: UBIFS file-system description object
*/
void ubifs_tnc_close(struct ubifs_info *c)
{
tnc_destroy_cnext(c);
if (c->zroot.znode) {
long n;
ubifs_destroy_tnc_subtree(c->zroot.znode);
n = atomic_long_read(&c->clean_zn_cnt);
atomic_long_sub(n, &ubifs_clean_zn_cnt);
}
kfree(c->gap_lebs);
kfree(c->ilebs);
destroy_old_idx(c);
}
/**
* left_znode - get the znode to the left.
* @c: UBIFS file-system description object
* @znode: znode
*
* This function returns a pointer to the znode to the left of @znode or NULL if
* there is not one. A negative error code is returned on failure.
*/
static struct ubifs_znode *left_znode(struct ubifs_info *c,
struct ubifs_znode *znode)
{
int level = znode->level;
while (1) {
int n = znode->iip - 1;
/* Go up until we can go left */
znode = znode->parent;
if (!znode)
return NULL;
if (n >= 0) {
/* Now go down the rightmost branch to 'level' */
znode = get_znode(c, znode, n);
if (IS_ERR(znode))
return znode;
while (znode->level != level) {
n = znode->child_cnt - 1;
znode = get_znode(c, znode, n);
if (IS_ERR(znode))
return znode;
}
break;
}
}
return znode;
}
/**
* right_znode - get the znode to the right.
* @c: UBIFS file-system description object
* @znode: znode
*
* This function returns a pointer to the znode to the right of @znode or NULL
* if there is not one. A negative error code is returned on failure.
*/
static struct ubifs_znode *right_znode(struct ubifs_info *c,
struct ubifs_znode *znode)
{
int level = znode->level;
while (1) {
int n = znode->iip + 1;
/* Go up until we can go right */
znode = znode->parent;
if (!znode)
return NULL;
if (n < znode->child_cnt) {
/* Now go down the leftmost branch to 'level' */
znode = get_znode(c, znode, n);
if (IS_ERR(znode))
return znode;
while (znode->level != level) {
znode = get_znode(c, znode, 0);
if (IS_ERR(znode))
return znode;
}
break;
}
}
return znode;
}
/**
* lookup_znode - find a particular indexing node from TNC.
* @c: UBIFS file-system description object
* @key: index node key to lookup
* @level: index node level
* @lnum: index node LEB number
* @offs: index node offset
*
* This function searches an indexing node by its first key @key and its
* address @lnum:@offs. It looks up the indexing tree by pulling all indexing
* nodes it traverses to TNC. This function is called for indexing nodes which
* were found on the media by scanning, for example when garbage-collecting or
* when doing in-the-gaps commit. This means that the indexing node which is
* looked for does not have to have exactly the same leftmost key @key, because
* the leftmost key may have been changed, in which case TNC will contain a
* dirty znode which still refers the same @lnum:@offs. This function is clever
* enough to recognize such indexing nodes.
*
* Note, if a znode was deleted or changed too much, then this function will
* not find it. For situations like this UBIFS has the old index RB-tree
* (indexed by @lnum:@offs).
*
* This function returns a pointer to the znode found or %NULL if it is not
* found. A negative error code is returned on failure.
*/
static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
union ubifs_key *key, int level,
int lnum, int offs)
{
struct ubifs_znode *znode, *zn;
int n, nn;
ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
/*
* The arguments have probably been read off flash, so don't assume
* they are valid.
*/
if (level < 0)
return ERR_PTR(-EINVAL);
/* Get the root znode */
znode = c->zroot.znode;
if (!znode) {
znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
if (IS_ERR(znode))
return znode;
}
/* Check if it is the one we are looking for */
if (c->zroot.lnum == lnum && c->zroot.offs == offs)
return znode;
/* Descend to the parent level i.e. (level + 1) */
if (level >= znode->level)
return NULL;
while (1) {
ubifs_search_zbranch(c, znode, key, &n);
if (n < 0) {
/*
* We reached a znode where the leftmost key is greater
* than the key we are searching for. This is the same
* situation as the one described in a huge comment at
* the end of the 'ubifs_lookup_level0()' function. And
* for exactly the same reasons we have to try to look
* left before giving up.
*/
znode = left_znode(c, znode);
if (!znode)
return NULL;
if (IS_ERR(znode))
return znode;
ubifs_search_zbranch(c, znode, key, &n);
ubifs_assert(n >= 0);
}
if (znode->level == level + 1)
break;
znode = get_znode(c, znode, n);
if (IS_ERR(znode))
return znode;
}
/* Check if the child is the one we are looking for */
if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs)
return get_znode(c, znode, n);
/* If the key is unique, there is nowhere else to look */
if (!is_hash_key(c, key))
return NULL;
/*
* The key is not unique and so may be also in the znodes to either
* side.
*/
zn = znode;
nn = n;
/* Look left */
while (1) {
/* Move one branch to the left */
if (n)
n -= 1;
else {
znode = left_znode(c, znode);
if (!znode)
break;
if (IS_ERR(znode))
return znode;
n = znode->child_cnt - 1;
}
/* Check it */
if (znode->zbranch[n].lnum == lnum &&
znode->zbranch[n].offs == offs)
return get_znode(c, znode, n);
/* Stop if the key is less than the one we are looking for */
if (keys_cmp(c, &znode->zbranch[n].key, key) < 0)
break;
}
/* Back to the middle */
znode = zn;
n = nn;
/* Look right */
while (1) {
/* Move one branch to the right */
if (++n >= znode->child_cnt) {
znode = right_znode(c, znode);
if (!znode)
break;
if (IS_ERR(znode))
return znode;
n = 0;
}
/* Check it */
if (znode->zbranch[n].lnum == lnum &&
znode->zbranch[n].offs == offs)
return get_znode(c, znode, n);
/* Stop if the key is greater than the one we are looking for */
if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
break;
}
return NULL;
}
/**
* is_idx_node_in_tnc - determine if an index node is in the TNC.
* @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
*
* This function returns %0 if the index node is not referred to in the TNC, %1
* if the index node is referred to in the TNC and the corresponding znode is
* dirty, %2 if an index node is referred to in the TNC and the corresponding
* znode is clean, and a negative error code in case of failure.
*
* Note, the @key argument has to be the key of the first child. Also note,
* this function relies on the fact that 0:0 is never a valid LEB number and
* offset for a main-area node.
*/
int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
int lnum, int offs)
{
struct ubifs_znode *znode;
znode = lookup_znode(c, key, level, lnum, offs);
if (!znode)
return 0;
if (IS_ERR(znode))
return PTR_ERR(znode);
return ubifs_zn_dirty(znode) ? 1 : 2;
}
/**
* is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC.
* @c: UBIFS file-system description object
* @key: node key
* @lnum: node LEB number
* @offs: node offset
*
* This function returns %1 if the node is referred to in the TNC, %0 if it is
* not, and a negative error code in case of failure.
*
* Note, this function relies on the fact that 0:0 is never a valid LEB number
* and offset for a main-area node.
*/
static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
int lnum, int offs)
{
struct ubifs_zbranch *zbr;
struct ubifs_znode *znode, *zn;
int n, found, err, nn;
const int unique = !is_hash_key(c, key);
found = ubifs_lookup_level0(c, key, &znode, &n);
if (found < 0)
return found; /* Error code */
if (!found)
return 0;
zbr = &znode->zbranch[n];
if (lnum == zbr->lnum && offs == zbr->offs)
return 1; /* Found it */
if (unique)
return 0;
/*
* Because the key is not unique, we have to look left
* and right as well
*/
zn = znode;
nn = n;
/* Look left */
while (1) {
err = tnc_prev(c, &znode, &n);
if (err == -ENOENT)
break;
if (err)
return err;
if (keys_cmp(c, key, &znode->zbranch[n].key))
break;
zbr = &znode->zbranch[n];
if (lnum == zbr->lnum && offs == zbr->offs)
return 1; /* Found it */
}
/* Look right */
znode = zn;
n = nn;
while (1) {
err = tnc_next(c, &znode, &n);
if (err) {
if (err == -ENOENT)
return 0;
return err;
}
if (keys_cmp(c, key, &znode->zbranch[n].key))
break;
zbr = &znode->zbranch[n];
if (lnum == zbr->lnum && offs == zbr->offs)
return 1; /* Found it */
}
return 0;
}
/**
* ubifs_tnc_has_node - determine whether a node is in the TNC.
* @c: UBIFS file-system description object
* @key: node key
* @level: index node level (if it is an index node)
* @lnum: node LEB number
* @offs: node offset
* @is_idx: non-zero if the node is an index node
*
* This function returns %1 if the node is in the TNC, %0 if it is not, and a
* negative error code in case of failure. For index nodes, @key has to be the
* key of the first child. An index node is considered to be in the TNC only if
* the corresponding znode is clean or has not been loaded.
*/
int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
int lnum, int offs, int is_idx)
{
int err;
mutex_lock(&c->tnc_mutex);
if (is_idx) {
err = is_idx_node_in_tnc(c, key, level, lnum, offs);
if (err < 0)
goto out_unlock;
if (err == 1)
/* The index node was found but it was dirty */
err = 0;
else if (err == 2)
/* The index node was found and it was clean */
err = 1;
else
BUG_ON(err != 0);
} else
err = is_leaf_node_in_tnc(c, key, lnum, offs);
out_unlock:
mutex_unlock(&c->tnc_mutex);
return err;
}
/**
* ubifs_dirty_idx_node - dirty an index node.
* @c: UBIFS file-system description object
* @key: index node key
* @level: index node level
* @lnum: index node LEB number
* @offs: index node offset
*
* This function loads and dirties an index node so that it can be garbage
* collected. The @key argument has to be the key of the first child. This
* function relies on the fact that 0:0 is never a valid LEB number and offset
* for a main-area node. Returns %0 on success and a negative error code on
* failure.
*/
int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
int lnum, int offs)
{
struct ubifs_znode *znode;
int err = 0;
mutex_lock(&c->tnc_mutex);
znode = lookup_znode(c, key, level, lnum, offs);
if (!znode)
goto out_unlock;
if (IS_ERR(znode)) {
err = PTR_ERR(znode);
goto out_unlock;
}
znode = dirty_cow_bottom_up(c, znode);
if (IS_ERR(znode)) {
err = PTR_ERR(znode);
goto out_unlock;
}
out_unlock:
mutex_unlock(&c->tnc_mutex);
return err;
}
#ifdef CONFIG_UBIFS_FS_DEBUG
/**
* dbg_check_inode_size - check if inode size is correct.
* @c: UBIFS file-system description object
* @inum: inode number
* @size: inode size
*
* This function makes sure that the inode size (@size) is correct and it does
* not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL
* if it has a data page beyond @size, and other negative error code in case of
* other errors.
*/
int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
loff_t size)
{
int err, n;
union ubifs_key from_key, to_key, *key;
struct ubifs_znode *znode;
unsigned int block;
if (!S_ISREG(inode->i_mode))
return 0;
if (!dbg_is_chk_gen(c))
return 0;
block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
data_key_init(c, &from_key, inode->i_ino, block);
highest_data_key(c, &to_key, inode->i_ino);
mutex_lock(&c->tnc_mutex);
err = ubifs_lookup_level0(c, &from_key, &znode, &n);
if (err < 0)
goto out_unlock;
if (err) {
err = -EINVAL;
key = &from_key;
goto out_dump;
}
err = tnc_next(c, &znode, &n);
if (err == -ENOENT) {
err = 0;
goto out_unlock;
}
if (err < 0)
goto out_unlock;
ubifs_assert(err == 0);
key = &znode->zbranch[n].key;
if (!key_in_range(c, key, &from_key, &to_key))
goto out_unlock;
out_dump:
block = key_block(c, key);
ubifs_err("inode %lu has size %lld, but there are data at offset %lld",
(unsigned long)inode->i_ino, size,
((loff_t)block) << UBIFS_BLOCK_SHIFT);
mutex_unlock(&c->tnc_mutex);
dbg_dump_inode(c, inode);
dbg_dump_stack();
return -EINVAL;
out_unlock:
mutex_unlock(&c->tnc_mutex);
return err;
}
#endif /* CONFIG_UBIFS_FS_DEBUG */