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stree.c
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/*
* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
*/
/*
* Written by Anatoly P. Pinchuk [email protected]
* Programm System Institute
* Pereslavl-Zalessky Russia
*/
/*
* This file contains functions dealing with S+tree
*
* B_IS_IN_TREE
* copy_item_head
* comp_short_keys
* comp_keys
* comp_short_le_keys
* le_key2cpu_key
* comp_le_keys
* bin_search
* get_lkey
* get_rkey
* key_in_buffer
* decrement_bcount
* reiserfs_check_path
* pathrelse_and_restore
* pathrelse
* search_by_key_reada
* search_by_key
* search_for_position_by_key
* comp_items
* prepare_for_direct_item
* prepare_for_direntry_item
* prepare_for_delete_or_cut
* calc_deleted_bytes_number
* init_tb_struct
* padd_item
* reiserfs_delete_item
* reiserfs_delete_solid_item
* reiserfs_delete_object
* maybe_indirect_to_direct
* indirect_to_direct_roll_back
* reiserfs_cut_from_item
* truncate_directory
* reiserfs_do_truncate
* reiserfs_paste_into_item
* reiserfs_insert_item
*/
#include <linux/time.h>
#include <linux/string.h>
#include <linux/pagemap.h>
#include "reiserfs.h"
#include <linux/buffer_head.h>
#include <linux/quotaops.h>
/* Does the buffer contain a disk block which is in the tree. */
inline int B_IS_IN_TREE(const struct buffer_head *bh)
{
RFALSE(B_LEVEL(bh) > MAX_HEIGHT,
"PAP-1010: block (%b) has too big level (%z)", bh, bh);
return (B_LEVEL(bh) != FREE_LEVEL);
}
//
// to gets item head in le form
//
inline void copy_item_head(struct item_head *to,
const struct item_head *from)
{
memcpy(to, from, IH_SIZE);
}
/* k1 is pointer to on-disk structure which is stored in little-endian
form. k2 is pointer to cpu variable. For key of items of the same
object this returns 0.
Returns: -1 if key1 < key2
0 if key1 == key2
1 if key1 > key2 */
inline int comp_short_keys(const struct reiserfs_key *le_key,
const struct cpu_key *cpu_key)
{
__u32 n;
n = le32_to_cpu(le_key->k_dir_id);
if (n < cpu_key->on_disk_key.k_dir_id)
return -1;
if (n > cpu_key->on_disk_key.k_dir_id)
return 1;
n = le32_to_cpu(le_key->k_objectid);
if (n < cpu_key->on_disk_key.k_objectid)
return -1;
if (n > cpu_key->on_disk_key.k_objectid)
return 1;
return 0;
}
/* k1 is pointer to on-disk structure which is stored in little-endian
form. k2 is pointer to cpu variable.
Compare keys using all 4 key fields.
Returns: -1 if key1 < key2 0
if key1 = key2 1 if key1 > key2 */
static inline int comp_keys(const struct reiserfs_key *le_key,
const struct cpu_key *cpu_key)
{
int retval;
retval = comp_short_keys(le_key, cpu_key);
if (retval)
return retval;
if (le_key_k_offset(le_key_version(le_key), le_key) <
cpu_key_k_offset(cpu_key))
return -1;
if (le_key_k_offset(le_key_version(le_key), le_key) >
cpu_key_k_offset(cpu_key))
return 1;
if (cpu_key->key_length == 3)
return 0;
/* this part is needed only when tail conversion is in progress */
if (le_key_k_type(le_key_version(le_key), le_key) <
cpu_key_k_type(cpu_key))
return -1;
if (le_key_k_type(le_key_version(le_key), le_key) >
cpu_key_k_type(cpu_key))
return 1;
return 0;
}
inline int comp_short_le_keys(const struct reiserfs_key *key1,
const struct reiserfs_key *key2)
{
__u32 *k1_u32, *k2_u32;
int key_length = REISERFS_SHORT_KEY_LEN;
k1_u32 = (__u32 *) key1;
k2_u32 = (__u32 *) key2;
for (; key_length--; ++k1_u32, ++k2_u32) {
if (le32_to_cpu(*k1_u32) < le32_to_cpu(*k2_u32))
return -1;
if (le32_to_cpu(*k1_u32) > le32_to_cpu(*k2_u32))
return 1;
}
return 0;
}
inline void le_key2cpu_key(struct cpu_key *to, const struct reiserfs_key *from)
{
int version;
to->on_disk_key.k_dir_id = le32_to_cpu(from->k_dir_id);
to->on_disk_key.k_objectid = le32_to_cpu(from->k_objectid);
// find out version of the key
version = le_key_version(from);
to->version = version;
to->on_disk_key.k_offset = le_key_k_offset(version, from);
to->on_disk_key.k_type = le_key_k_type(version, from);
}
// this does not say which one is bigger, it only returns 1 if keys
// are not equal, 0 otherwise
inline int comp_le_keys(const struct reiserfs_key *k1,
const struct reiserfs_key *k2)
{
return memcmp(k1, k2, sizeof(struct reiserfs_key));
}
/**************************************************************************
* Binary search toolkit function *
* Search for an item in the array by the item key *
* Returns: 1 if found, 0 if not found; *
* *pos = number of the searched element if found, else the *
* number of the first element that is larger than key. *
**************************************************************************/
/* For those not familiar with binary search: lbound is the leftmost item that it
could be, rbound the rightmost item that it could be. We examine the item
halfway between lbound and rbound, and that tells us either that we can increase
lbound, or decrease rbound, or that we have found it, or if lbound <= rbound that
there are no possible items, and we have not found it. With each examination we
cut the number of possible items it could be by one more than half rounded down,
or we find it. */
static inline int bin_search(const void *key, /* Key to search for. */
const void *base, /* First item in the array. */
int num, /* Number of items in the array. */
int width, /* Item size in the array.
searched. Lest the reader be
confused, note that this is crafted
as a general function, and when it
is applied specifically to the array
of item headers in a node, width
is actually the item header size not
the item size. */
int *pos /* Number of the searched for element. */
)
{
int rbound, lbound, j;
for (j = ((rbound = num - 1) + (lbound = 0)) / 2;
lbound <= rbound; j = (rbound + lbound) / 2)
switch (comp_keys
((struct reiserfs_key *)((char *)base + j * width),
(struct cpu_key *)key)) {
case -1:
lbound = j + 1;
continue;
case 1:
rbound = j - 1;
continue;
case 0:
*pos = j;
return ITEM_FOUND; /* Key found in the array. */
}
/* bin_search did not find given key, it returns position of key,
that is minimal and greater than the given one. */
*pos = lbound;
return ITEM_NOT_FOUND;
}
/* Minimal possible key. It is never in the tree. */
const struct reiserfs_key MIN_KEY = { 0, 0, {{0, 0},} };
/* Maximal possible key. It is never in the tree. */
static const struct reiserfs_key MAX_KEY = {
__constant_cpu_to_le32(0xffffffff),
__constant_cpu_to_le32(0xffffffff),
{{__constant_cpu_to_le32(0xffffffff),
__constant_cpu_to_le32(0xffffffff)},}
};
/* Get delimiting key of the buffer by looking for it in the buffers in the path, starting from the bottom
of the path, and going upwards. We must check the path's validity at each step. If the key is not in
the path, there is no delimiting key in the tree (buffer is first or last buffer in tree), and in this
case we return a special key, either MIN_KEY or MAX_KEY. */
static inline const struct reiserfs_key *get_lkey(const struct treepath *chk_path,
const struct super_block *sb)
{
int position, path_offset = chk_path->path_length;
struct buffer_head *parent;
RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET,
"PAP-5010: invalid offset in the path");
/* While not higher in path than first element. */
while (path_offset-- > FIRST_PATH_ELEMENT_OFFSET) {
RFALSE(!buffer_uptodate
(PATH_OFFSET_PBUFFER(chk_path, path_offset)),
"PAP-5020: parent is not uptodate");
/* Parent at the path is not in the tree now. */
if (!B_IS_IN_TREE
(parent =
PATH_OFFSET_PBUFFER(chk_path, path_offset)))
return &MAX_KEY;
/* Check whether position in the parent is correct. */
if ((position =
PATH_OFFSET_POSITION(chk_path,
path_offset)) >
B_NR_ITEMS(parent))
return &MAX_KEY;
/* Check whether parent at the path really points to the child. */
if (B_N_CHILD_NUM(parent, position) !=
PATH_OFFSET_PBUFFER(chk_path,
path_offset + 1)->b_blocknr)
return &MAX_KEY;
/* Return delimiting key if position in the parent is not equal to zero. */
if (position)
return B_N_PDELIM_KEY(parent, position - 1);
}
/* Return MIN_KEY if we are in the root of the buffer tree. */
if (PATH_OFFSET_PBUFFER(chk_path, FIRST_PATH_ELEMENT_OFFSET)->
b_blocknr == SB_ROOT_BLOCK(sb))
return &MIN_KEY;
return &MAX_KEY;
}
/* Get delimiting key of the buffer at the path and its right neighbor. */
inline const struct reiserfs_key *get_rkey(const struct treepath *chk_path,
const struct super_block *sb)
{
int position, path_offset = chk_path->path_length;
struct buffer_head *parent;
RFALSE(path_offset < FIRST_PATH_ELEMENT_OFFSET,
"PAP-5030: invalid offset in the path");
while (path_offset-- > FIRST_PATH_ELEMENT_OFFSET) {
RFALSE(!buffer_uptodate
(PATH_OFFSET_PBUFFER(chk_path, path_offset)),
"PAP-5040: parent is not uptodate");
/* Parent at the path is not in the tree now. */
if (!B_IS_IN_TREE
(parent =
PATH_OFFSET_PBUFFER(chk_path, path_offset)))
return &MIN_KEY;
/* Check whether position in the parent is correct. */
if ((position =
PATH_OFFSET_POSITION(chk_path,
path_offset)) >
B_NR_ITEMS(parent))
return &MIN_KEY;
/* Check whether parent at the path really points to the child. */
if (B_N_CHILD_NUM(parent, position) !=
PATH_OFFSET_PBUFFER(chk_path,
path_offset + 1)->b_blocknr)
return &MIN_KEY;
/* Return delimiting key if position in the parent is not the last one. */
if (position != B_NR_ITEMS(parent))
return B_N_PDELIM_KEY(parent, position);
}
/* Return MAX_KEY if we are in the root of the buffer tree. */
if (PATH_OFFSET_PBUFFER(chk_path, FIRST_PATH_ELEMENT_OFFSET)->
b_blocknr == SB_ROOT_BLOCK(sb))
return &MAX_KEY;
return &MIN_KEY;
}
/* Check whether a key is contained in the tree rooted from a buffer at a path. */
/* This works by looking at the left and right delimiting keys for the buffer in the last path_element in
the path. These delimiting keys are stored at least one level above that buffer in the tree. If the
buffer is the first or last node in the tree order then one of the delimiting keys may be absent, and in
this case get_lkey and get_rkey return a special key which is MIN_KEY or MAX_KEY. */
static inline int key_in_buffer(struct treepath *chk_path, /* Path which should be checked. */
const struct cpu_key *key, /* Key which should be checked. */
struct super_block *sb
)
{
RFALSE(!key || chk_path->path_length < FIRST_PATH_ELEMENT_OFFSET
|| chk_path->path_length > MAX_HEIGHT,
"PAP-5050: pointer to the key(%p) is NULL or invalid path length(%d)",
key, chk_path->path_length);
RFALSE(!PATH_PLAST_BUFFER(chk_path)->b_bdev,
"PAP-5060: device must not be NODEV");
if (comp_keys(get_lkey(chk_path, sb), key) == 1)
/* left delimiting key is bigger, that the key we look for */
return 0;
/* if ( comp_keys(key, get_rkey(chk_path, sb)) != -1 ) */
if (comp_keys(get_rkey(chk_path, sb), key) != 1)
/* key must be less than right delimitiing key */
return 0;
return 1;
}
int reiserfs_check_path(struct treepath *p)
{
RFALSE(p->path_length != ILLEGAL_PATH_ELEMENT_OFFSET,
"path not properly relsed");
return 0;
}
/* Drop the reference to each buffer in a path and restore
* dirty bits clean when preparing the buffer for the log.
* This version should only be called from fix_nodes() */
void pathrelse_and_restore(struct super_block *sb,
struct treepath *search_path)
{
int path_offset = search_path->path_length;
RFALSE(path_offset < ILLEGAL_PATH_ELEMENT_OFFSET,
"clm-4000: invalid path offset");
while (path_offset > ILLEGAL_PATH_ELEMENT_OFFSET) {
struct buffer_head *bh;
bh = PATH_OFFSET_PBUFFER(search_path, path_offset--);
reiserfs_restore_prepared_buffer(sb, bh);
brelse(bh);
}
search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET;
}
/* Drop the reference to each buffer in a path */
void pathrelse(struct treepath *search_path)
{
int path_offset = search_path->path_length;
RFALSE(path_offset < ILLEGAL_PATH_ELEMENT_OFFSET,
"PAP-5090: invalid path offset");
while (path_offset > ILLEGAL_PATH_ELEMENT_OFFSET)
brelse(PATH_OFFSET_PBUFFER(search_path, path_offset--));
search_path->path_length = ILLEGAL_PATH_ELEMENT_OFFSET;
}
static int is_leaf(char *buf, int blocksize, struct buffer_head *bh)
{
struct block_head *blkh;
struct item_head *ih;
int used_space;
int prev_location;
int i;
int nr;
blkh = (struct block_head *)buf;
if (blkh_level(blkh) != DISK_LEAF_NODE_LEVEL) {
reiserfs_warning(NULL, "reiserfs-5080",
"this should be caught earlier");
return 0;
}
nr = blkh_nr_item(blkh);
if (nr < 1 || nr > ((blocksize - BLKH_SIZE) / (IH_SIZE + MIN_ITEM_LEN))) {
/* item number is too big or too small */
reiserfs_warning(NULL, "reiserfs-5081",
"nr_item seems wrong: %z", bh);
return 0;
}
ih = (struct item_head *)(buf + BLKH_SIZE) + nr - 1;
used_space = BLKH_SIZE + IH_SIZE * nr + (blocksize - ih_location(ih));
if (used_space != blocksize - blkh_free_space(blkh)) {
/* free space does not match to calculated amount of use space */
reiserfs_warning(NULL, "reiserfs-5082",
"free space seems wrong: %z", bh);
return 0;
}
// FIXME: it is_leaf will hit performance too much - we may have
// return 1 here
/* check tables of item heads */
ih = (struct item_head *)(buf + BLKH_SIZE);
prev_location = blocksize;
for (i = 0; i < nr; i++, ih++) {
if (le_ih_k_type(ih) == TYPE_ANY) {
reiserfs_warning(NULL, "reiserfs-5083",
"wrong item type for item %h",
ih);
return 0;
}
if (ih_location(ih) >= blocksize
|| ih_location(ih) < IH_SIZE * nr) {
reiserfs_warning(NULL, "reiserfs-5084",
"item location seems wrong: %h",
ih);
return 0;
}
if (ih_item_len(ih) < 1
|| ih_item_len(ih) > MAX_ITEM_LEN(blocksize)) {
reiserfs_warning(NULL, "reiserfs-5085",
"item length seems wrong: %h",
ih);
return 0;
}
if (prev_location - ih_location(ih) != ih_item_len(ih)) {
reiserfs_warning(NULL, "reiserfs-5086",
"item location seems wrong "
"(second one): %h", ih);
return 0;
}
prev_location = ih_location(ih);
}
// one may imagine much more checks
return 1;
}
/* returns 1 if buf looks like an internal node, 0 otherwise */
static int is_internal(char *buf, int blocksize, struct buffer_head *bh)
{
struct block_head *blkh;
int nr;
int used_space;
blkh = (struct block_head *)buf;
nr = blkh_level(blkh);
if (nr <= DISK_LEAF_NODE_LEVEL || nr > MAX_HEIGHT) {
/* this level is not possible for internal nodes */
reiserfs_warning(NULL, "reiserfs-5087",
"this should be caught earlier");
return 0;
}
nr = blkh_nr_item(blkh);
if (nr > (blocksize - BLKH_SIZE - DC_SIZE) / (KEY_SIZE + DC_SIZE)) {
/* for internal which is not root we might check min number of keys */
reiserfs_warning(NULL, "reiserfs-5088",
"number of key seems wrong: %z", bh);
return 0;
}
used_space = BLKH_SIZE + KEY_SIZE * nr + DC_SIZE * (nr + 1);
if (used_space != blocksize - blkh_free_space(blkh)) {
reiserfs_warning(NULL, "reiserfs-5089",
"free space seems wrong: %z", bh);
return 0;
}
// one may imagine much more checks
return 1;
}
// make sure that bh contains formatted node of reiserfs tree of
// 'level'-th level
static int is_tree_node(struct buffer_head *bh, int level)
{
if (B_LEVEL(bh) != level) {
reiserfs_warning(NULL, "reiserfs-5090", "node level %d does "
"not match to the expected one %d",
B_LEVEL(bh), level);
return 0;
}
if (level == DISK_LEAF_NODE_LEVEL)
return is_leaf(bh->b_data, bh->b_size, bh);
return is_internal(bh->b_data, bh->b_size, bh);
}
#define SEARCH_BY_KEY_READA 16
/*
* The function is NOT SCHEDULE-SAFE!
* It might unlock the write lock if we needed to wait for a block
* to be read. Note that in this case it won't recover the lock to avoid
* high contention resulting from too much lock requests, especially
* the caller (search_by_key) will perform other schedule-unsafe
* operations just after calling this function.
*
* @return depth of lock to be restored after read completes
*/
static int search_by_key_reada(struct super_block *s,
struct buffer_head **bh,
b_blocknr_t *b, int num)
{
int i, j;
int depth = -1;
for (i = 0; i < num; i++) {
bh[i] = sb_getblk(s, b[i]);
}
/*
* We are going to read some blocks on which we
* have a reference. It's safe, though we might be
* reading blocks concurrently changed if we release
* the lock. But it's still fine because we check later
* if the tree changed
*/
for (j = 0; j < i; j++) {
/*
* note, this needs attention if we are getting rid of the BKL
* you have to make sure the prepared bit isn't set on this buffer
*/
if (!buffer_uptodate(bh[j])) {
if (depth == -1)
depth = reiserfs_write_unlock_nested(s);
ll_rw_block(READA, 1, bh + j);
}
brelse(bh[j]);
}
return depth;
}
/**************************************************************************
* Algorithm SearchByKey *
* look for item in the Disk S+Tree by its key *
* Input: sb - super block *
* key - pointer to the key to search *
* Output: ITEM_FOUND, ITEM_NOT_FOUND or IO_ERROR *
* search_path - path from the root to the needed leaf *
**************************************************************************/
/* This function fills up the path from the root to the leaf as it
descends the tree looking for the key. It uses reiserfs_bread to
try to find buffers in the cache given their block number. If it
does not find them in the cache it reads them from disk. For each
node search_by_key finds using reiserfs_bread it then uses
bin_search to look through that node. bin_search will find the
position of the block_number of the next node if it is looking
through an internal node. If it is looking through a leaf node
bin_search will find the position of the item which has key either
equal to given key, or which is the maximal key less than the given
key. search_by_key returns a path that must be checked for the
correctness of the top of the path but need not be checked for the
correctness of the bottom of the path */
/* The function is NOT SCHEDULE-SAFE! */
int search_by_key(struct super_block *sb, const struct cpu_key *key, /* Key to search. */
struct treepath *search_path,/* This structure was
allocated and initialized
by the calling
function. It is filled up
by this function. */
int stop_level /* How far down the tree to search. To
stop at leaf level - set to
DISK_LEAF_NODE_LEVEL */
)
{
b_blocknr_t block_number;
int expected_level;
struct buffer_head *bh;
struct path_element *last_element;
int node_level, retval;
int right_neighbor_of_leaf_node;
int fs_gen;
struct buffer_head *reada_bh[SEARCH_BY_KEY_READA];
b_blocknr_t reada_blocks[SEARCH_BY_KEY_READA];
int reada_count = 0;
#ifdef CONFIG_REISERFS_CHECK
int repeat_counter = 0;
#endif
PROC_INFO_INC(sb, search_by_key);
/* As we add each node to a path we increase its count. This means that
we must be careful to release all nodes in a path before we either
discard the path struct or re-use the path struct, as we do here. */
pathrelse(search_path);
right_neighbor_of_leaf_node = 0;
/* With each iteration of this loop we search through the items in the
current node, and calculate the next current node(next path element)
for the next iteration of this loop.. */
block_number = SB_ROOT_BLOCK(sb);
expected_level = -1;
while (1) {
#ifdef CONFIG_REISERFS_CHECK
if (!(++repeat_counter % 50000))
reiserfs_warning(sb, "PAP-5100",
"%s: there were %d iterations of "
"while loop looking for key %K",
current->comm, repeat_counter,
key);
#endif
/* prep path to have another element added to it. */
last_element =
PATH_OFFSET_PELEMENT(search_path,
++search_path->path_length);
fs_gen = get_generation(sb);
/* Read the next tree node, and set the last element in the path to
have a pointer to it. */
if ((bh = last_element->pe_buffer =
sb_getblk(sb, block_number))) {
/*
* We'll need to drop the lock if we encounter any
* buffers that need to be read. If all of them are
* already up to date, we don't need to drop the lock.
*/
int depth = -1;
if (!buffer_uptodate(bh) && reada_count > 1)
depth = search_by_key_reada(sb, reada_bh,
reada_blocks, reada_count);
if (!buffer_uptodate(bh) && depth == -1)
depth = reiserfs_write_unlock_nested(sb);
ll_rw_block(READ, 1, &bh);
wait_on_buffer(bh);
if (depth != -1)
reiserfs_write_lock_nested(sb, depth);
if (!buffer_uptodate(bh))
goto io_error;
} else {
io_error:
search_path->path_length--;
pathrelse(search_path);
return IO_ERROR;
}
reada_count = 0;
if (expected_level == -1)
expected_level = SB_TREE_HEIGHT(sb);
expected_level--;
/* It is possible that schedule occurred. We must check whether the key
to search is still in the tree rooted from the current buffer. If
not then repeat search from the root. */
if (fs_changed(fs_gen, sb) &&
(!B_IS_IN_TREE(bh) ||
B_LEVEL(bh) != expected_level ||
!key_in_buffer(search_path, key, sb))) {
PROC_INFO_INC(sb, search_by_key_fs_changed);
PROC_INFO_INC(sb, search_by_key_restarted);
PROC_INFO_INC(sb,
sbk_restarted[expected_level - 1]);
pathrelse(search_path);
/* Get the root block number so that we can repeat the search
starting from the root. */
block_number = SB_ROOT_BLOCK(sb);
expected_level = -1;
right_neighbor_of_leaf_node = 0;
/* repeat search from the root */
continue;
}
/* only check that the key is in the buffer if key is not
equal to the MAX_KEY. Latter case is only possible in
"finish_unfinished()" processing during mount. */
RFALSE(comp_keys(&MAX_KEY, key) &&
!key_in_buffer(search_path, key, sb),
"PAP-5130: key is not in the buffer");
#ifdef CONFIG_REISERFS_CHECK
if (REISERFS_SB(sb)->cur_tb) {
print_cur_tb("5140");
reiserfs_panic(sb, "PAP-5140",
"schedule occurred in do_balance!");
}
#endif
// make sure, that the node contents look like a node of
// certain level
if (!is_tree_node(bh, expected_level)) {
reiserfs_error(sb, "vs-5150",
"invalid format found in block %ld. "
"Fsck?", bh->b_blocknr);
pathrelse(search_path);
return IO_ERROR;
}
/* ok, we have acquired next formatted node in the tree */
node_level = B_LEVEL(bh);
PROC_INFO_BH_STAT(sb, bh, node_level - 1);
RFALSE(node_level < stop_level,
"vs-5152: tree level (%d) is less than stop level (%d)",
node_level, stop_level);
retval = bin_search(key, B_N_PITEM_HEAD(bh, 0),
B_NR_ITEMS(bh),
(node_level ==
DISK_LEAF_NODE_LEVEL) ? IH_SIZE :
KEY_SIZE,
&(last_element->pe_position));
if (node_level == stop_level) {
return retval;
}
/* we are not in the stop level */
if (retval == ITEM_FOUND)
/* item has been found, so we choose the pointer which is to the right of the found one */
last_element->pe_position++;
/* if item was not found we choose the position which is to
the left of the found item. This requires no code,
bin_search did it already. */
/* So we have chosen a position in the current node which is
an internal node. Now we calculate child block number by
position in the node. */
block_number =
B_N_CHILD_NUM(bh, last_element->pe_position);
/* if we are going to read leaf nodes, try for read ahead as well */
if ((search_path->reada & PATH_READA) &&
node_level == DISK_LEAF_NODE_LEVEL + 1) {
int pos = last_element->pe_position;
int limit = B_NR_ITEMS(bh);
struct reiserfs_key *le_key;
if (search_path->reada & PATH_READA_BACK)
limit = 0;
while (reada_count < SEARCH_BY_KEY_READA) {
if (pos == limit)
break;
reada_blocks[reada_count++] =
B_N_CHILD_NUM(bh, pos);
if (search_path->reada & PATH_READA_BACK)
pos--;
else
pos++;
/*
* check to make sure we're in the same object
*/
le_key = B_N_PDELIM_KEY(bh, pos);
if (le32_to_cpu(le_key->k_objectid) !=
key->on_disk_key.k_objectid) {
break;
}
}
}
}
}
/* Form the path to an item and position in this item which contains
file byte defined by key. If there is no such item
corresponding to the key, we point the path to the item with
maximal key less than key, and *pos_in_item is set to one
past the last entry/byte in the item. If searching for entry in a
directory item, and it is not found, *pos_in_item is set to one
entry more than the entry with maximal key which is less than the
sought key.
Note that if there is no entry in this same node which is one more,
then we point to an imaginary entry. for direct items, the
position is in units of bytes, for indirect items the position is
in units of blocknr entries, for directory items the position is in
units of directory entries. */
/* The function is NOT SCHEDULE-SAFE! */
int search_for_position_by_key(struct super_block *sb, /* Pointer to the super block. */
const struct cpu_key *p_cpu_key, /* Key to search (cpu variable) */
struct treepath *search_path /* Filled up by this function. */
)
{
struct item_head *p_le_ih; /* pointer to on-disk structure */
int blk_size;
loff_t item_offset, offset;
struct reiserfs_dir_entry de;
int retval;
/* If searching for directory entry. */
if (is_direntry_cpu_key(p_cpu_key))
return search_by_entry_key(sb, p_cpu_key, search_path,
&de);
/* If not searching for directory entry. */
/* If item is found. */
retval = search_item(sb, p_cpu_key, search_path);
if (retval == IO_ERROR)
return retval;
if (retval == ITEM_FOUND) {
RFALSE(!ih_item_len
(B_N_PITEM_HEAD
(PATH_PLAST_BUFFER(search_path),
PATH_LAST_POSITION(search_path))),
"PAP-5165: item length equals zero");
pos_in_item(search_path) = 0;
return POSITION_FOUND;
}
RFALSE(!PATH_LAST_POSITION(search_path),
"PAP-5170: position equals zero");
/* Item is not found. Set path to the previous item. */
p_le_ih =
B_N_PITEM_HEAD(PATH_PLAST_BUFFER(search_path),
--PATH_LAST_POSITION(search_path));
blk_size = sb->s_blocksize;
if (comp_short_keys(&(p_le_ih->ih_key), p_cpu_key)) {
return FILE_NOT_FOUND;
}
// FIXME: quite ugly this far
item_offset = le_ih_k_offset(p_le_ih);
offset = cpu_key_k_offset(p_cpu_key);
/* Needed byte is contained in the item pointed to by the path. */
if (item_offset <= offset &&
item_offset + op_bytes_number(p_le_ih, blk_size) > offset) {
pos_in_item(search_path) = offset - item_offset;
if (is_indirect_le_ih(p_le_ih)) {
pos_in_item(search_path) /= blk_size;
}
return POSITION_FOUND;
}
/* Needed byte is not contained in the item pointed to by the
path. Set pos_in_item out of the item. */
if (is_indirect_le_ih(p_le_ih))
pos_in_item(search_path) =
ih_item_len(p_le_ih) / UNFM_P_SIZE;
else
pos_in_item(search_path) = ih_item_len(p_le_ih);
return POSITION_NOT_FOUND;
}
/* Compare given item and item pointed to by the path. */
int comp_items(const struct item_head *stored_ih, const struct treepath *path)
{
struct buffer_head *bh = PATH_PLAST_BUFFER(path);
struct item_head *ih;
/* Last buffer at the path is not in the tree. */
if (!B_IS_IN_TREE(bh))
return 1;
/* Last path position is invalid. */
if (PATH_LAST_POSITION(path) >= B_NR_ITEMS(bh))
return 1;
/* we need only to know, whether it is the same item */
ih = get_ih(path);
return memcmp(stored_ih, ih, IH_SIZE);
}
/* unformatted nodes are not logged anymore, ever. This is safe
** now
*/
#define held_by_others(bh) (atomic_read(&(bh)->b_count) > 1)
// block can not be forgotten as it is in I/O or held by someone
#define block_in_use(bh) (buffer_locked(bh) || (held_by_others(bh)))
// prepare for delete or cut of direct item
static inline int prepare_for_direct_item(struct treepath *path,
struct item_head *le_ih,
struct inode *inode,
loff_t new_file_length, int *cut_size)
{
loff_t round_len;
if (new_file_length == max_reiserfs_offset(inode)) {
/* item has to be deleted */
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
return M_DELETE;
}
// new file gets truncated
if (get_inode_item_key_version(inode) == KEY_FORMAT_3_6) {
//
round_len = ROUND_UP(new_file_length);
/* this was new_file_length < le_ih ... */
if (round_len < le_ih_k_offset(le_ih)) {
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
return M_DELETE; /* Delete this item. */
}
/* Calculate first position and size for cutting from item. */
pos_in_item(path) = round_len - (le_ih_k_offset(le_ih) - 1);
*cut_size = -(ih_item_len(le_ih) - pos_in_item(path));
return M_CUT; /* Cut from this item. */
}
// old file: items may have any length
if (new_file_length < le_ih_k_offset(le_ih)) {
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
return M_DELETE; /* Delete this item. */
}
/* Calculate first position and size for cutting from item. */
*cut_size = -(ih_item_len(le_ih) -
(pos_in_item(path) =
new_file_length + 1 - le_ih_k_offset(le_ih)));
return M_CUT; /* Cut from this item. */
}
static inline int prepare_for_direntry_item(struct treepath *path,
struct item_head *le_ih,
struct inode *inode,
loff_t new_file_length,
int *cut_size)
{
if (le_ih_k_offset(le_ih) == DOT_OFFSET &&
new_file_length == max_reiserfs_offset(inode)) {
RFALSE(ih_entry_count(le_ih) != 2,
"PAP-5220: incorrect empty directory item (%h)", le_ih);
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
return M_DELETE; /* Delete the directory item containing "." and ".." entry. */
}
if (ih_entry_count(le_ih) == 1) {
/* Delete the directory item such as there is one record only
in this item */
*cut_size = -(IH_SIZE + ih_item_len(le_ih));
return M_DELETE;
}
/* Cut one record from the directory item. */
*cut_size =
-(DEH_SIZE +
entry_length(get_last_bh(path), le_ih, pos_in_item(path)));
return M_CUT;
}
#define JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD (2 * JOURNAL_PER_BALANCE_CNT + 1)
/* If the path points to a directory or direct item, calculate mode and the size cut, for balance.
If the path points to an indirect item, remove some number of its unformatted nodes.
In case of file truncate calculate whether this item must be deleted/truncated or last
unformatted node of this item will be converted to a direct item.
This function returns a determination of what balance mode the calling function should employ. */
static char prepare_for_delete_or_cut(struct reiserfs_transaction_handle *th, struct inode *inode, struct treepath *path, const struct cpu_key *item_key, int *removed, /* Number of unformatted nodes which were removed
from end of the file. */
int *cut_size, unsigned long long new_file_length /* MAX_KEY_OFFSET in case of delete. */
)
{
struct super_block *sb = inode->i_sb;
struct item_head *p_le_ih = PATH_PITEM_HEAD(path);
struct buffer_head *bh = PATH_PLAST_BUFFER(path);
BUG_ON(!th->t_trans_id);
/* Stat_data item. */
if (is_statdata_le_ih(p_le_ih)) {
RFALSE(new_file_length != max_reiserfs_offset(inode),
"PAP-5210: mode must be M_DELETE");