of: MSI: Simplify irqdomain lookup

[linux/fpc-iii.git] / fs / reiserfs / stree.c

/*
 *  Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
 */

/*
 *  Written by Anatoly P. Pinchuk pap@namesys.botik.ru
 *  Programm System Institute
 *  Pereslavl-Zalessky Russia
 */

#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 get 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. */
                             /*
                              * 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 width,
                             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 = {
        cpu_to_le32(0xffffffff),
        cpu_to_le32(0xffffffff),
        {{cpu_to_le32(0xffffffff),
          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 internal_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 internal_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(
                                /* Path which should be checked. */
                                struct treepath *chk_path,
                                /* Key which should be checked. */
                                const struct cpu_key *key,
                                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));

        /* free space does not match to calculated amount of use space */
        if (used_space != blocksize - blkh_free_space(blkh)) {
                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 many 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);
        /* for internal which is not root we might check min number of keys */
        if (nr > (blocksize - BLKH_SIZE - DC_SIZE) / (KEY_SIZE + DC_SIZE)) {
                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 many 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;
}

/*
 * 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
 */
/*
 * search_by_key - search for key (and item) in stree
 * @sb: superblock
 * @key: pointer to key to search for
 * @search_path: Allocated and initialized struct treepath; Returned filled
 *               on success.
 * @stop_level: How far down the tree to search, Use DISK_LEAF_NODE_LEVEL to
 *              stop at leaf level.
 *
 * The function is NOT SCHEDULE-SAFE!
 */
int search_by_key(struct super_block *sb, const struct cpu_key *key,
                  struct treepath *search_path, int stop_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, item_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 */
                /*
                 * item has been found, so we choose the pointer which
                 * is to the right of the found one
                 */
                if (retval == ITEM_FOUND)
                        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 = internal_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,
                               /* Key to search (cpu variable) */
                               const struct cpu_key *p_cpu_key,
                               /* Filled up by this function. */
                               struct treepath *search_path)
{
        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
                       (item_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 =
            item_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 = tp_item_head(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));
                /* Delete the directory item containing "." and ".." entry. */
                return M_DELETE;
        }

        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,
                                      /*
                                       * Number of unformatted nodes
                                       * which were removed from end
                                       * of the file.
                                       */
                                      int *removed,
                                      int *cut_size,
                                      /* MAX_KEY_OFFSET in case of delete. */
                                      unsigned long long new_file_length
    )
{
        struct super_block *sb = inode->i_sb;
        struct item_head *p_le_ih = tp_item_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");

                *cut_size = -(IH_SIZE + ih_item_len(p_le_ih));
                return M_DELETE;
        }

        /* Directory item. */
        if (is_direntry_le_ih(p_le_ih))
                return prepare_for_direntry_item(path, p_le_ih, inode,
                                                 new_file_length,
                                                 cut_size);

        /* Direct item. */
        if (is_direct_le_ih(p_le_ih))
                return prepare_for_direct_item(path, p_le_ih, inode,
                                               new_file_length, cut_size);

        /* Case of an indirect item. */
        {
            int blk_size = sb->s_blocksize;
            struct item_head s_ih;
            int need_re_search;
            int delete = 0;
            int result = M_CUT;
            int pos = 0;

            if ( new_file_length == max_reiserfs_offset (inode) ) {
                /*
                 * prepare_for_delete_or_cut() is called by
                 * reiserfs_delete_item()
                 */
                new_file_length = 0;
                delete = 1;
            }

            do {
                need_re_search = 0;
                *cut_size = 0;
                bh = PATH_PLAST_BUFFER(path);
                copy_item_head(&s_ih, tp_item_head(path));
                pos = I_UNFM_NUM(&s_ih);

                while (le_ih_k_offset (&s_ih) + (pos - 1) * blk_size > new_file_length) {
                    __le32 *unfm;
                    __u32 block;

                    /*
                     * Each unformatted block deletion may involve
                     * one additional bitmap block into the transaction,
                     * thereby the initial journal space reservation
                     * might not be enough.
                     */
                    if (!delete && (*cut_size) != 0 &&
                        reiserfs_transaction_free_space(th) < JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD)
                        break;

                    unfm = (__le32 *)ih_item_body(bh, &s_ih) + pos - 1;
                    block = get_block_num(unfm, 0);

                    if (block != 0) {
                        reiserfs_prepare_for_journal(sb, bh, 1);
                        put_block_num(unfm, 0, 0);
                        journal_mark_dirty(th, bh);
                        reiserfs_free_block(th, inode, block, 1);
                    }

                    reiserfs_cond_resched(sb);

                    if (item_moved (&s_ih, path))  {
                        need_re_search = 1;
                        break;
                    }

                    pos --;
                    (*removed)++;
                    (*cut_size) -= UNFM_P_SIZE;

                    if (pos == 0) {
                        (*cut_size) -= IH_SIZE;
                        result = M_DELETE;
                        break;
                    }
                }
                /*
                 * a trick.  If the buffer has been logged, this will
                 * do nothing.  If we've broken the loop without logging
                 * it, it will restore the buffer
                 */
                reiserfs_restore_prepared_buffer(sb, bh);
            } while (need_re_search &&
                     search_for_position_by_key(sb, item_key, path) == POSITION_FOUND);
            pos_in_item(path) = pos * UNFM_P_SIZE;

            if (*cut_size == 0) {
                /*
                 * Nothing was cut. maybe convert last unformatted node to the
                 * direct item?
                 */
                result = M_CONVERT;
            }
            return result;
        }
}

/* Calculate number of bytes which will be deleted or cut during balance */
static int calc_deleted_bytes_number(struct tree_balance *tb, char mode)
{
        int del_size;
        struct item_head *p_le_ih = tp_item_head(tb->tb_path);

        if (is_statdata_le_ih(p_le_ih))
                return 0;

        del_size =
            (mode ==
             M_DELETE) ? ih_item_len(p_le_ih) : -tb->insert_size[0];
        if (is_direntry_le_ih(p_le_ih)) {
                /*
                 * return EMPTY_DIR_SIZE; We delete emty directories only.
                 * we can't use EMPTY_DIR_SIZE, as old format dirs have a
                 * different empty size.  ick. FIXME, is this right?
                 */
                return del_size;
        }

        if (is_indirect_le_ih(p_le_ih))
                del_size = (del_size / UNFM_P_SIZE) *
                                (PATH_PLAST_BUFFER(tb->tb_path)->b_size);
        return del_size;
}

static void init_tb_struct(struct reiserfs_transaction_handle *th,
                           struct tree_balance *tb,
                           struct super_block *sb,
                           struct treepath *path, int size)
{

        BUG_ON(!th->t_trans_id);

        memset(tb, '\0', sizeof(struct tree_balance));
        tb->transaction_handle = th;
        tb->tb_sb = sb;
        tb->tb_path = path;
        PATH_OFFSET_PBUFFER(path, ILLEGAL_PATH_ELEMENT_OFFSET) = NULL;
        PATH_OFFSET_POSITION(path, ILLEGAL_PATH_ELEMENT_OFFSET) = 0;
        tb->insert_size[0] = size;
}

void padd_item(char *item, int total_length, int length)
{
        int i;

        for (i = total_length; i > length;)
                item[--i] = 0;
}

#ifdef REISERQUOTA_DEBUG
char key2type(struct reiserfs_key *ih)
{
        if (is_direntry_le_key(2, ih))
                return 'd';
        if (is_direct_le_key(2, ih))
                return 'D';
        if (is_indirect_le_key(2, ih))
                return 'i';
        if (is_statdata_le_key(2, ih))
                return 's';
        return 'u';
}

char head2type(struct item_head *ih)
{
        if (is_direntry_le_ih(ih))
                return 'd';
        if (is_direct_le_ih(ih))
                return 'D';
        if (is_indirect_le_ih(ih))
                return 'i';
        if (is_statdata_le_ih(ih))
                return 's';
        return 'u';
}
#endif

/*
 * Delete object item.
 * th       - active transaction handle
 * path     - path to the deleted item
 * item_key - key to search for the deleted item
 * indode   - used for updating i_blocks and quotas
 * un_bh    - NULL or unformatted node pointer
 */
int reiserfs_delete_item(struct reiserfs_transaction_handle *th,
                         struct treepath *path, const struct cpu_key *item_key,
                         struct inode *inode, struct buffer_head *un_bh)
{
        struct super_block *sb = inode->i_sb;
        struct tree_balance s_del_balance;
        struct item_head s_ih;
        struct item_head *q_ih;
        int quota_cut_bytes;
        int ret_value, del_size, removed;
        int depth;

#ifdef CONFIG_REISERFS_CHECK
        char mode;
        int iter = 0;
#endif

        BUG_ON(!th->t_trans_id);

        init_tb_struct(th, &s_del_balance, sb, path,
                       0 /*size is unknown */ );

        while (1) {
                removed = 0;

#ifdef CONFIG_REISERFS_CHECK
                iter++;
                mode =
#endif
                    prepare_for_delete_or_cut(th, inode, path,
                                              item_key, &removed,
                                              &del_size,
                                              max_reiserfs_offset(inode));

                RFALSE(mode != M_DELETE, "PAP-5320: mode must be M_DELETE");

                copy_item_head(&s_ih, tp_item_head(path));
                s_del_balance.insert_size[0] = del_size;

                ret_value = fix_nodes(M_DELETE, &s_del_balance, NULL, NULL);
                if (ret_value != REPEAT_SEARCH)
                        break;

                PROC_INFO_INC(sb, delete_item_restarted);

                /* file system changed, repeat search */
                ret_value =
                    search_for_position_by_key(sb, item_key, path);
                if (ret_value == IO_ERROR)
                        break;
                if (ret_value == FILE_NOT_FOUND) {
                        reiserfs_warning(sb, "vs-5340",
                                         "no items of the file %K found",
                                         item_key);
                        break;
                }
        }                       /* while (1) */

        if (ret_value != CARRY_ON) {
                unfix_nodes(&s_del_balance);
                return 0;
        }

        /* reiserfs_delete_item returns item length when success */
        ret_value = calc_deleted_bytes_number(&s_del_balance, M_DELETE);
        q_ih = tp_item_head(path);
        quota_cut_bytes = ih_item_len(q_ih);

        /*
         * hack so the quota code doesn't have to guess if the file has a
         * tail.  On tail insert, we allocate quota for 1 unformatted node.
         * We test the offset because the tail might have been
         * split into multiple items, and we only want to decrement for
         * the unfm node once
         */
        if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(q_ih)) {
                if ((le_ih_k_offset(q_ih) & (sb->s_blocksize - 1)) == 1) {
                        quota_cut_bytes = sb->s_blocksize + UNFM_P_SIZE;
                } else {
                        quota_cut_bytes = 0;
                }
        }

        if (un_bh) {
                int off;
                char *data;

                /*
                 * We are in direct2indirect conversion, so move tail contents
                 * to the unformatted node
                 */
                /*
                 * note, we do the copy before preparing the buffer because we
                 * don't care about the contents of the unformatted node yet.
                 * the only thing we really care about is the direct item's
                 * data is in the unformatted node.
                 *
                 * Otherwise, we would have to call
                 * reiserfs_prepare_for_journal on the unformatted node,
                 * which might schedule, meaning we'd have to loop all the
                 * way back up to the start of the while loop.
                 *
                 * The unformatted node must be dirtied later on.  We can't be
                 * sure here if the entire tail has been deleted yet.
                 *
                 * un_bh is from the page cache (all unformatted nodes are
                 * from the page cache) and might be a highmem page.  So, we
                 * can't use un_bh->b_data.
                 * -clm
                 */

                data = kmap_atomic(un_bh->b_page);
                off = ((le_ih_k_offset(&s_ih) - 1) & (PAGE_CACHE_SIZE - 1));
                memcpy(data + off,
                       ih_item_body(PATH_PLAST_BUFFER(path), &s_ih),
                       ret_value);
                kunmap_atomic(data);
        }

        /* Perform balancing after all resources have been collected at once. */
        do_balance(&s_del_balance, NULL, NULL, M_DELETE);

#ifdef REISERQUOTA_DEBUG
        reiserfs_debug(sb, REISERFS_DEBUG_CODE,
                       "reiserquota delete_item(): freeing %u, id=%u type=%c",
                       quota_cut_bytes, inode->i_uid, head2type(&s_ih));
#endif
        depth = reiserfs_write_unlock_nested(inode->i_sb);
        dquot_free_space_nodirty(inode, quota_cut_bytes);
        reiserfs_write_lock_nested(inode->i_sb, depth);

        /* Return deleted body length */
        return ret_value;
}

/*
 * Summary Of Mechanisms For Handling Collisions Between Processes:
 *
 *  deletion of the body of the object is performed by iput(), with the
 *  result that if multiple processes are operating on a file, the
 *  deletion of the body of the file is deferred until the last process
 *  that has an open inode performs its iput().
 *
 *  writes and truncates are protected from collisions by use of
 *  semaphores.
 *
 *  creates, linking, and mknod are protected from collisions with other
 *  processes by making the reiserfs_add_entry() the last step in the
 *  creation, and then rolling back all changes if there was a collision.
 *  - Hans
*/

/* this deletes item which never gets split */
void reiserfs_delete_solid_item(struct reiserfs_transaction_handle *th,
                                struct inode *inode, struct reiserfs_key *key)
{
        struct super_block *sb = th->t_super;
        struct tree_balance tb;
        INITIALIZE_PATH(path);
        int item_len = 0;
        int tb_init = 0;
        struct cpu_key cpu_key;
        int retval;
        int quota_cut_bytes = 0;

        BUG_ON(!th->t_trans_id);

        le_key2cpu_key(&cpu_key, key);

        while (1) {
                retval = search_item(th->t_super, &cpu_key, &path);
                if (retval == IO_ERROR) {
                        reiserfs_error(th->t_super, "vs-5350",
                                       "i/o failure occurred trying "
                                       "to delete %K", &cpu_key);
                        break;
                }
                if (retval != ITEM_FOUND) {
                        pathrelse(&path);
                        /*
                         * No need for a warning, if there is just no free
                         * space to insert '..' item into the
                         * newly-created subdir
                         */
                        if (!
                            ((unsigned long long)
                             GET_HASH_VALUE(le_key_k_offset
                                            (le_key_version(key), key)) == 0
                             && (unsigned long long)
                             GET_GENERATION_NUMBER(le_key_k_offset
                                                   (le_key_version(key),
                                                    key)) == 1))
                                reiserfs_warning(th->t_super, "vs-5355",
                                                 "%k not found", key);
                        break;
                }
                if (!tb_init) {
                        tb_init = 1;
                        item_len = ih_item_len(tp_item_head(&path));
                        init_tb_struct(th, &tb, th->t_super, &path,
                                       -(IH_SIZE + item_len));
                }
                quota_cut_bytes = ih_item_len(tp_item_head(&path));

                retval = fix_nodes(M_DELETE, &tb, NULL, NULL);
                if (retval == REPEAT_SEARCH) {
                        PROC_INFO_INC(th->t_super, delete_solid_item_restarted);
                        continue;
                }

                if (retval == CARRY_ON) {
                        do_balance(&tb, NULL, NULL, M_DELETE);
                        /*
                         * Should we count quota for item? (we don't
                         * count quotas for save-links)
                         */
                        if (inode) {
                                int depth;
#ifdef REISERQUOTA_DEBUG
                                reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
                                               "reiserquota delete_solid_item(): freeing %u id=%u type=%c",
                                               quota_cut_bytes, inode->i_uid,
                                               key2type(key));
#endif
                                depth = reiserfs_write_unlock_nested(sb);
                                dquot_free_space_nodirty(inode,
                                                         quota_cut_bytes);
                                reiserfs_write_lock_nested(sb, depth);
                        }
                        break;
                }

                /* IO_ERROR, NO_DISK_SPACE, etc */
                reiserfs_warning(th->t_super, "vs-5360",
                                 "could not delete %K due to fix_nodes failure",
                                 &cpu_key);
                unfix_nodes(&tb);
                break;
        }

        reiserfs_check_path(&path);
}

int reiserfs_delete_object(struct reiserfs_transaction_handle *th,
                           struct inode *inode)
{
        int err;
        inode->i_size = 0;
        BUG_ON(!th->t_trans_id);

        /* for directory this deletes item containing "." and ".." */
        err =
            reiserfs_do_truncate(th, inode, NULL, 0 /*no timestamp updates */ );
        if (err)
                return err;

#if defined( USE_INODE_GENERATION_COUNTER )
        if (!old_format_only(th->t_super)) {
                __le32 *inode_generation;

                inode_generation =
                    &REISERFS_SB(th->t_super)->s_rs->s_inode_generation;
                le32_add_cpu(inode_generation, 1);
        }
/* USE_INODE_GENERATION_COUNTER */
#endif
        reiserfs_delete_solid_item(th, inode, INODE_PKEY(inode));

        return err;
}

static void unmap_buffers(struct page *page, loff_t pos)
{
        struct buffer_head *bh;
        struct buffer_head *head;
        struct buffer_head *next;
        unsigned long tail_index;
        unsigned long cur_index;

        if (page) {
                if (page_has_buffers(page)) {
                        tail_index = pos & (PAGE_CACHE_SIZE - 1);
                        cur_index = 0;
                        head = page_buffers(page);
                        bh = head;
                        do {
                                next = bh->b_this_page;

                                /*
                                 * we want to unmap the buffers that contain
                                 * the tail, and all the buffers after it
                                 * (since the tail must be at the end of the
                                 * file).  We don't want to unmap file data
                                 * before the tail, since it might be dirty
                                 * and waiting to reach disk
                                 */
                                cur_index += bh->b_size;
                                if (cur_index > tail_index) {
                                        reiserfs_unmap_buffer(bh);
                                }
                                bh = next;
                        } while (bh != head);
                }
        }
}

static int maybe_indirect_to_direct(struct reiserfs_transaction_handle *th,
                                    struct inode *inode,
                                    struct page *page,
                                    struct treepath *path,
                                    const struct cpu_key *item_key,
                                    loff_t new_file_size, char *mode)
{
        struct super_block *sb = inode->i_sb;
        int block_size = sb->s_blocksize;
        int cut_bytes;
        BUG_ON(!th->t_trans_id);
        BUG_ON(new_file_size != inode->i_size);

        /*
         * the page being sent in could be NULL if there was an i/o error
         * reading in the last block.  The user will hit problems trying to
         * read the file, but for now we just skip the indirect2direct
         */
        if (atomic_read(&inode->i_count) > 1 ||
            !tail_has_to_be_packed(inode) ||
            !page || (REISERFS_I(inode)->i_flags & i_nopack_mask)) {
                /* leave tail in an unformatted node */
                *mode = M_SKIP_BALANCING;
                cut_bytes =
                    block_size - (new_file_size & (block_size - 1));
                pathrelse(path);
                return cut_bytes;
        }

        /* Perform the conversion to a direct_item. */
        return indirect2direct(th, inode, page, path, item_key,
                               new_file_size, mode);
}

/*
 * we did indirect_to_direct conversion. And we have inserted direct
 * item successesfully, but there were no disk space to cut unfm
 * pointer being converted. Therefore we have to delete inserted
 * direct item(s)
 */
static void indirect_to_direct_roll_back(struct reiserfs_transaction_handle *th,
                                         struct inode *inode, struct treepath *path)
{
        struct cpu_key tail_key;
        int tail_len;
        int removed;
        BUG_ON(!th->t_trans_id);

        make_cpu_key(&tail_key, inode, inode->i_size + 1, TYPE_DIRECT, 4);
        tail_key.key_length = 4;

        tail_len =
            (cpu_key_k_offset(&tail_key) & (inode->i_sb->s_blocksize - 1)) - 1;
        while (tail_len) {
                /* look for the last byte of the tail */
                if (search_for_position_by_key(inode->i_sb, &tail_key, path) ==
                    POSITION_NOT_FOUND)
                        reiserfs_panic(inode->i_sb, "vs-5615",
                                       "found invalid item");
                RFALSE(path->pos_in_item !=
                       ih_item_len(tp_item_head(path)) - 1,
                       "vs-5616: appended bytes found");
                PATH_LAST_POSITION(path)--;

                removed =
                    reiserfs_delete_item(th, path, &tail_key, inode,
                                         NULL /*unbh not needed */ );
                RFALSE(removed <= 0
                       || removed > tail_len,
                       "vs-5617: there was tail %d bytes, removed item length %d bytes",
                       tail_len, removed);
                tail_len -= removed;
                set_cpu_key_k_offset(&tail_key,
                                     cpu_key_k_offset(&tail_key) - removed);
        }
        reiserfs_warning(inode->i_sb, "reiserfs-5091", "indirect_to_direct "
                         "conversion has been rolled back due to "
                         "lack of disk space");
        mark_inode_dirty(inode);
}

/* (Truncate or cut entry) or delete object item. Returns < 0 on failure */
int reiserfs_cut_from_item(struct reiserfs_transaction_handle *th,
                           struct treepath *path,
                           struct cpu_key *item_key,
                           struct inode *inode,
                           struct page *page, loff_t new_file_size)
{
        struct super_block *sb = inode->i_sb;
        /*
         * Every function which is going to call do_balance must first
         * create a tree_balance structure.  Then it must fill up this
         * structure by using the init_tb_struct and fix_nodes functions.
         * After that we can make tree balancing.
         */
        struct tree_balance s_cut_balance;
        struct item_head *p_le_ih;
        int cut_size = 0;       /* Amount to be cut. */
        int ret_value = CARRY_ON;
        int removed = 0;        /* Number of the removed unformatted nodes. */
        int is_inode_locked = 0;
        char mode;              /* Mode of the balance. */
        int retval2 = -1;
        int quota_cut_bytes;
        loff_t tail_pos = 0;
        int depth;

        BUG_ON(!th->t_trans_id);

        init_tb_struct(th, &s_cut_balance, inode->i_sb, path,
                       cut_size);

        /*
         * Repeat this loop until we either cut the item without needing
         * to balance, or we fix_nodes without schedule occurring
         */
        while (1) {
                /*
                 * Determine the balance mode, position of the first byte to
                 * be cut, and size to be cut.  In case of the indirect item
                 * free unformatted nodes which are pointed to by the cut
                 * pointers.
                 */

                mode =
                    prepare_for_delete_or_cut(th, inode, path,
                                              item_key, &removed,
                                              &cut_size, new_file_size);
                if (mode == M_CONVERT) {
                        /*
                         * convert last unformatted node to direct item or
                         * leave tail in the unformatted node
                         */
                        RFALSE(ret_value != CARRY_ON,
                               "PAP-5570: can not convert twice");

                        ret_value =
                            maybe_indirect_to_direct(th, inode, page,
                                                     path, item_key,
                                                     new_file_size, &mode);
                        if (mode == M_SKIP_BALANCING)
                                /* tail has been left in the unformatted node */
                                return ret_value;

                        is_inode_locked = 1;

                        /*
                         * removing of last unformatted node will
                         * change value we have to return to truncate.
                         * Save it
                         */
                        retval2 = ret_value;

                        /*
                         * So, we have performed the first part of the
                         * conversion:
                         * inserting the new direct item.  Now we are
                         * removing the last unformatted node pointer.
                         * Set key to search for it.
                         */
                        set_cpu_key_k_type(item_key, TYPE_INDIRECT);
                        item_key->key_length = 4;
                        new_file_size -=
                            (new_file_size & (sb->s_blocksize - 1));
                        tail_pos = new_file_size;
                        set_cpu_key_k_offset(item_key, new_file_size + 1);
                        if (search_for_position_by_key
                            (sb, item_key,
                             path) == POSITION_NOT_FOUND) {
                                print_block(PATH_PLAST_BUFFER(path), 3,
                                            PATH_LAST_POSITION(path) - 1,
                                            PATH_LAST_POSITION(path) + 1);
                                reiserfs_panic(sb, "PAP-5580", "item to "
                                               "convert does not exist (%K)",
                                               item_key);
                        }
                        continue;
                }
                if (cut_size == 0) {
                        pathrelse(path);
                        return 0;
                }

                s_cut_balance.insert_size[0] = cut_size;

                ret_value = fix_nodes(mode, &s_cut_balance, NULL, NULL);
                if (ret_value != REPEAT_SEARCH)
                        break;

                PROC_INFO_INC(sb, cut_from_item_restarted);

                ret_value =
                    search_for_position_by_key(sb, item_key, path);
                if (ret_value == POSITION_FOUND)
                        continue;

                reiserfs_warning(sb, "PAP-5610", "item %K not found",
                                 item_key);
                unfix_nodes(&s_cut_balance);
                return (ret_value == IO_ERROR) ? -EIO : -ENOENT;
        }                       /* while */

        /* check fix_nodes results (IO_ERROR or NO_DISK_SPACE) */
        if (ret_value != CARRY_ON) {
                if (is_inode_locked) {
                        /*
                         * FIXME: this seems to be not needed: we are always
                         * able to cut item
                         */
                        indirect_to_direct_roll_back(th, inode, path);
                }
                if (ret_value == NO_DISK_SPACE)
                        reiserfs_warning(sb, "reiserfs-5092",
                                         "NO_DISK_SPACE");
                unfix_nodes(&s_cut_balance);
                return -EIO;
        }

        /* go ahead and perform balancing */

        RFALSE(mode == M_PASTE || mode == M_INSERT, "invalid mode");

        /* Calculate number of bytes that need to be cut from the item. */
        quota_cut_bytes =
            (mode ==
             M_DELETE) ? ih_item_len(tp_item_head(path)) : -s_cut_balance.
            insert_size[0];
        if (retval2 == -1)
                ret_value = calc_deleted_bytes_number(&s_cut_balance, mode);
        else
                ret_value = retval2;

        /*
         * For direct items, we only change the quota when deleting the last
         * item.
         */
        p_le_ih = tp_item_head(s_cut_balance.tb_path);
        if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(p_le_ih)) {
                if (mode == M_DELETE &&
                    (le_ih_k_offset(p_le_ih) & (sb->s_blocksize - 1)) ==
                    1) {
                        /* FIXME: this is to keep 3.5 happy */
                        REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
                        quota_cut_bytes = sb->s_blocksize + UNFM_P_SIZE;
                } else {
                        quota_cut_bytes = 0;
                }
        }
#ifdef CONFIG_REISERFS_CHECK
        if (is_inode_locked) {
                struct item_head *le_ih =
                    tp_item_head(s_cut_balance.tb_path);
                /*
                 * we are going to complete indirect2direct conversion. Make
                 * sure, that we exactly remove last unformatted node pointer
                 * of the item
                 */
                if (!is_indirect_le_ih(le_ih))
                        reiserfs_panic(sb, "vs-5652",
                                       "item must be indirect %h", le_ih);

                if (mode == M_DELETE && ih_item_len(le_ih) != UNFM_P_SIZE)
                        reiserfs_panic(sb, "vs-5653", "completing "
                                       "indirect2direct conversion indirect "
                                       "item %h being deleted must be of "
                                       "4 byte long", le_ih);

                if (mode == M_CUT
                    && s_cut_balance.insert_size[0] != -UNFM_P_SIZE) {
                        reiserfs_panic(sb, "vs-5654", "can not complete "
                                       "indirect2direct conversion of %h "
                                       "(CUT, insert_size==%d)",
                                       le_ih, s_cut_balance.insert_size[0]);
                }
                /*
                 * it would be useful to make sure, that right neighboring
                 * item is direct item of this file
                 */
        }
#endif

        do_balance(&s_cut_balance, NULL, NULL, mode);
        if (is_inode_locked) {
                /*
                 * we've done an indirect->direct conversion.  when the
                 * data block was freed, it was removed from the list of
                 * blocks that must be flushed before the transaction
                 * commits, make sure to unmap and invalidate it
                 */
                unmap_buffers(page, tail_pos);
                REISERFS_I(inode)->i_flags &= ~i_pack_on_close_mask;
        }
#ifdef REISERQUOTA_DEBUG
        reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
                       "reiserquota cut_from_item(): freeing %u id=%u type=%c",
                       quota_cut_bytes, inode->i_uid, '?');
#endif
        depth = reiserfs_write_unlock_nested(sb);
        dquot_free_space_nodirty(inode, quota_cut_bytes);
        reiserfs_write_lock_nested(sb, depth);
        return ret_value;
}

static void truncate_directory(struct reiserfs_transaction_handle *th,
                               struct inode *inode)
{
        BUG_ON(!th->t_trans_id);
        if (inode->i_nlink)
                reiserfs_error(inode->i_sb, "vs-5655", "link count != 0");

        set_le_key_k_offset(KEY_FORMAT_3_5, INODE_PKEY(inode), DOT_OFFSET);
        set_le_key_k_type(KEY_FORMAT_3_5, INODE_PKEY(inode), TYPE_DIRENTRY);
        reiserfs_delete_solid_item(th, inode, INODE_PKEY(inode));
        reiserfs_update_sd(th, inode);
        set_le_key_k_offset(KEY_FORMAT_3_5, INODE_PKEY(inode), SD_OFFSET);
        set_le_key_k_type(KEY_FORMAT_3_5, INODE_PKEY(inode), TYPE_STAT_DATA);
}

/*
 * Truncate file to the new size. Note, this must be called with a
 * transaction already started
 */
int reiserfs_do_truncate(struct reiserfs_transaction_handle *th,
                         struct inode *inode,   /* ->i_size contains new size */
                         struct page *page,     /* up to date for last block */
                         /*
                          * when it is called by file_release to convert
                          * the tail - no timestamps should be updated
                          */
                         int update_timestamps
    )
{
        INITIALIZE_PATH(s_search_path); /* Path to the current object item. */
        struct item_head *p_le_ih;      /* Pointer to an item header. */

        /* Key to search for a previous file item. */
        struct cpu_key s_item_key;
        loff_t file_size,       /* Old file size. */
         new_file_size; /* New file size. */
        int deleted;            /* Number of deleted or truncated bytes. */
        int retval;
        int err = 0;

        BUG_ON(!th->t_trans_id);
        if (!
            (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
             || S_ISLNK(inode->i_mode)))
                return 0;

        /* deletion of directory - no need to update timestamps */
        if (S_ISDIR(inode->i_mode)) {
                truncate_directory(th, inode);
                return 0;
        }

        /* Get new file size. */
        new_file_size = inode->i_size;

        /* FIXME: note, that key type is unimportant here */
        make_cpu_key(&s_item_key, inode, max_reiserfs_offset(inode),
                     TYPE_DIRECT, 3);

        retval =
            search_for_position_by_key(inode->i_sb, &s_item_key,
                                       &s_search_path);
        if (retval == IO_ERROR) {
                reiserfs_error(inode->i_sb, "vs-5657",
                               "i/o failure occurred trying to truncate %K",
                               &s_item_key);
                err = -EIO;
                goto out;
        }
        if (retval == POSITION_FOUND || retval == FILE_NOT_FOUND) {
                reiserfs_error(inode->i_sb, "PAP-5660",
                               "wrong result %d of search for %K", retval,
                               &s_item_key);

                err = -EIO;
                goto out;
        }

        s_search_path.pos_in_item--;

        /* Get real file size (total length of all file items) */
        p_le_ih = tp_item_head(&s_search_path);
        if (is_statdata_le_ih(p_le_ih))
                file_size = 0;
        else {
                loff_t offset = le_ih_k_offset(p_le_ih);
                int bytes =
                    op_bytes_number(p_le_ih, inode->i_sb->s_blocksize);

                /*
                 * this may mismatch with real file size: if last direct item
                 * had no padding zeros and last unformatted node had no free
                 * space, this file would have this file size
                 */
                file_size = offset + bytes - 1;
        }
        /*
         * are we doing a full truncate or delete, if so
         * kick in the reada code
         */
        if (new_file_size == 0)
                s_search_path.reada = PATH_READA | PATH_READA_BACK;

        if (file_size == 0 || file_size < new_file_size) {
                goto update_and_out;
        }

        /* Update key to search for the last file item. */
        set_cpu_key_k_offset(&s_item_key, file_size);

        do {
                /* Cut or delete file item. */
                deleted =
                    reiserfs_cut_from_item(th, &s_search_path, &s_item_key,
                                           inode, page, new_file_size);
                if (deleted < 0) {
                        reiserfs_warning(inode->i_sb, "vs-5665",
                                         "reiserfs_cut_from_item failed");
                        reiserfs_check_path(&s_search_path);
                        return 0;
                }

                RFALSE(deleted > file_size,
                       "PAP-5670: reiserfs_cut_from_item: too many bytes deleted: deleted %d, file_size %lu, item_key %K",
                       deleted, file_size, &s_item_key);

                /* Change key to search the last file item. */
                file_size -= deleted;

                set_cpu_key_k_offset(&s_item_key, file_size);

                /*
                 * While there are bytes to truncate and previous
                 * file item is presented in the tree.
                 */

                /*
                 * This loop could take a really long time, and could log
                 * many more blocks than a transaction can hold.  So, we do
                 * a polite journal end here, and if the transaction needs
                 * ending, we make sure the file is consistent before ending
                 * the current trans and starting a new one
                 */
                if (journal_transaction_should_end(th, 0) ||
                    reiserfs_transaction_free_space(th) <= JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD) {
                        pathrelse(&s_search_path);

                        if (update_timestamps) {
                                inode->i_mtime = CURRENT_TIME_SEC;
                                inode->i_ctime = CURRENT_TIME_SEC;
                        }
                        reiserfs_update_sd(th, inode);

                        err = journal_end(th);
                        if (err)
                                goto out;
                        err = journal_begin(th, inode->i_sb,
                                            JOURNAL_FOR_FREE_BLOCK_AND_UPDATE_SD + JOURNAL_PER_BALANCE_CNT * 4) ;
                        if (err)
                                goto out;
                        reiserfs_update_inode_transaction(inode);
                }
        } while (file_size > ROUND_UP(new_file_size) &&
                 search_for_position_by_key(inode->i_sb, &s_item_key,
                                            &s_search_path) == POSITION_FOUND);

        RFALSE(file_size > ROUND_UP(new_file_size),
               "PAP-5680: truncate did not finish: new_file_size %lld, current %lld, oid %d",
               new_file_size, file_size, s_item_key.on_disk_key.k_objectid);

update_and_out:
        if (update_timestamps) {
                /* this is truncate, not file closing */
                inode->i_mtime = CURRENT_TIME_SEC;
                inode->i_ctime = CURRENT_TIME_SEC;
        }
        reiserfs_update_sd(th, inode);

out:
        pathrelse(&s_search_path);
        return err;
}

#ifdef CONFIG_REISERFS_CHECK
/* this makes sure, that we __append__, not overwrite or add holes */
static void check_research_for_paste(struct treepath *path,
                                     const struct cpu_key *key)
{
        struct item_head *found_ih = tp_item_head(path);

        if (is_direct_le_ih(found_ih)) {
                if (le_ih_k_offset(found_ih) +
                    op_bytes_number(found_ih,
                                    get_last_bh(path)->b_size) !=
                    cpu_key_k_offset(key)
                    || op_bytes_number(found_ih,
                                       get_last_bh(path)->b_size) !=
                    pos_in_item(path))
                        reiserfs_panic(NULL, "PAP-5720", "found direct item "
                                       "%h or position (%d) does not match "
                                       "to key %K", found_ih,
                                       pos_in_item(path), key);
        }
        if (is_indirect_le_ih(found_ih)) {
                if (le_ih_k_offset(found_ih) +
                    op_bytes_number(found_ih,
                                    get_last_bh(path)->b_size) !=
                    cpu_key_k_offset(key)
                    || I_UNFM_NUM(found_ih) != pos_in_item(path)
                    || get_ih_free_space(found_ih) != 0)
                        reiserfs_panic(NULL, "PAP-5730", "found indirect "
                                       "item (%h) or position (%d) does not "
                                       "match to key (%K)",
                                       found_ih, pos_in_item(path), key);
        }
}
#endif                          /* config reiserfs check */

/*
 * Paste bytes to the existing item.
 * Returns bytes number pasted into the item.
 */
int reiserfs_paste_into_item(struct reiserfs_transaction_handle *th,
                             /* Path to the pasted item. */
                             struct treepath *search_path,
                             /* Key to search for the needed item. */
                             const struct cpu_key *key,
                             /* Inode item belongs to */
                             struct inode *inode,
                             /* Pointer to the bytes to paste. */
                             const char *body,
                             /* Size of pasted bytes. */
                             int pasted_size)
{
        struct super_block *sb = inode->i_sb;
        struct tree_balance s_paste_balance;
        int retval;
        int fs_gen;
        int depth;

        BUG_ON(!th->t_trans_id);

        fs_gen = get_generation(inode->i_sb);

#ifdef REISERQUOTA_DEBUG
        reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
                       "reiserquota paste_into_item(): allocating %u id=%u type=%c",
                       pasted_size, inode->i_uid,
                       key2type(&key->on_disk_key));
#endif

        depth = reiserfs_write_unlock_nested(sb);
        retval = dquot_alloc_space_nodirty(inode, pasted_size);
        reiserfs_write_lock_nested(sb, depth);
        if (retval) {
                pathrelse(search_path);
                return retval;
        }
        init_tb_struct(th, &s_paste_balance, th->t_super, search_path,
                       pasted_size);
#ifdef DISPLACE_NEW_PACKING_LOCALITIES
        s_paste_balance.key = key->on_disk_key;
#endif

        /* DQUOT_* can schedule, must check before the fix_nodes */
        if (fs_changed(fs_gen, inode->i_sb)) {
                goto search_again;
        }

        while ((retval =
                fix_nodes(M_PASTE, &s_paste_balance, NULL,
                          body)) == REPEAT_SEARCH) {
search_again:
                /* file system changed while we were in the fix_nodes */
                PROC_INFO_INC(th->t_super, paste_into_item_restarted);
                retval =
                    search_for_position_by_key(th->t_super, key,
                                               search_path);
                if (retval == IO_ERROR) {
                        retval = -EIO;
                        goto error_out;
                }
                if (retval == POSITION_FOUND) {
                        reiserfs_warning(inode->i_sb, "PAP-5710",
                                         "entry or pasted byte (%K) exists",
                                         key);
                        retval = -EEXIST;
                        goto error_out;
                }
#ifdef CONFIG_REISERFS_CHECK
                check_research_for_paste(search_path, key);
#endif
        }

        /*
         * Perform balancing after all resources are collected by fix_nodes,
         * and accessing them will not risk triggering schedule.
         */
        if (retval == CARRY_ON) {
                do_balance(&s_paste_balance, NULL /*ih */ , body, M_PASTE);
                return 0;
        }
        retval = (retval == NO_DISK_SPACE) ? -ENOSPC : -EIO;
error_out:
        /* this also releases the path */
        unfix_nodes(&s_paste_balance);
#ifdef REISERQUOTA_DEBUG
        reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
                       "reiserquota paste_into_item(): freeing %u id=%u type=%c",
                       pasted_size, inode->i_uid,
                       key2type(&key->on_disk_key));
#endif
        depth = reiserfs_write_unlock_nested(sb);
        dquot_free_space_nodirty(inode, pasted_size);
        reiserfs_write_lock_nested(sb, depth);
        return retval;
}

/*
 * Insert new item into the buffer at the path.
 * th   - active transaction handle
 * path - path to the inserted item
 * ih   - pointer to the item header to insert
 * body - pointer to the bytes to insert
 */
int reiserfs_insert_item(struct reiserfs_transaction_handle *th,
                         struct treepath *path, const struct cpu_key *key,
                         struct item_head *ih, struct inode *inode,
                         const char *body)
{
        struct tree_balance s_ins_balance;
        int retval;
        int fs_gen = 0;
        int quota_bytes = 0;

        BUG_ON(!th->t_trans_id);

        if (inode) {            /* Do we count quotas for item? */
                int depth;
                fs_gen = get_generation(inode->i_sb);
                quota_bytes = ih_item_len(ih);

                /*
                 * hack so the quota code doesn't have to guess
                 * if the file has a tail, links are always tails,
                 * so there's no guessing needed
                 */
                if (!S_ISLNK(inode->i_mode) && is_direct_le_ih(ih))
                        quota_bytes = inode->i_sb->s_blocksize + UNFM_P_SIZE;
#ifdef REISERQUOTA_DEBUG
                reiserfs_debug(inode->i_sb, REISERFS_DEBUG_CODE,
                               "reiserquota insert_item(): allocating %u id=%u type=%c",
                               quota_bytes, inode->i_uid, head2type(ih));
#endif
                /*
                 * We can't dirty inode here. It would be immediately
                 * written but appropriate stat item isn't inserted yet...
                 */
                depth = reiserfs_write_unlock_nested(inode->i_sb);
                retval = dquot_alloc_space_nodirty(inode, quota_bytes);
                reiserfs_write_lock_nested(inode->i_sb, depth);
                if (retval) {
                        pathrelse(path);
                        return retval;
                }
        }
        init_tb_struct(th, &s_ins_balance, th->t_super, path,
                       IH_SIZE + ih_item_len(ih));
#ifdef DISPLACE_NEW_PACKING_LOCALITIES
        s_ins_balance.key = key->on_disk_key;
#endif
        /*
         * DQUOT_* can schedule, must check to be sure calling
         * fix_nodes is safe
         */
        if (inode && fs_changed(fs_gen, inode->i_sb)) {
                goto search_again;
        }

        while ((retval =
                fix_nodes(M_INSERT, &s_ins_balance, ih,
                          body)) == REPEAT_SEARCH) {
search_again:
                /* file system changed while we were in the fix_nodes */
                PROC_INFO_INC(th->t_super, insert_item_restarted);
                retval = search_item(th->t_super, key, path);
                if (retval == IO_ERROR) {
                        retval = -EIO;
                        goto error_out;
                }
                if (retval == ITEM_FOUND) {
                        reiserfs_warning(th->t_super, "PAP-5760",
                                         "key %K already exists in the tree",
                                         key);
                        retval = -EEXIST;
                        goto error_out;
                }
        }

        /* make balancing after all resources will be collected at a time */
        if (retval == CARRY_ON) {
                do_balance(&s_ins_balance, ih, body, M_INSERT);
                return 0;
        }

        retval = (retval == NO_DISK_SPACE) ? -ENOSPC : -EIO;
error_out:
        /* also releases the path */
        unfix_nodes(&s_ins_balance);
#ifdef REISERQUOTA_DEBUG
        reiserfs_debug(th->t_super, REISERFS_DEBUG_CODE,
                       "reiserquota insert_item(): freeing %u id=%u type=%c",
                       quota_bytes, inode->i_uid, head2type(ih));
#endif
        if (inode) {
                int depth = reiserfs_write_unlock_nested(inode->i_sb);
                dquot_free_space_nodirty(inode, quota_bytes);
                reiserfs_write_lock_nested(inode->i_sb, depth);
        }
        return retval;
}