Remove unnecessary cast in prefetch()

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ocfs2 / dir.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dir.c
 *
 * Creates, reads, walks and deletes directory-nodes
 *
 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
 *
 *  Portions of this code from linux/fs/ext3/dir.c
 *
 *  Copyright (C) 1992, 1993, 1994, 1995
 *  Remy Card (card@masi.ibp.fr)
 *  Laboratoire MASI - Institut Blaise pascal
 *  Universite Pierre et Marie Curie (Paris VI)
 *
 *   from
 *
 *   linux/fs/minix/dir.c
 *
 *   Copyright (C) 1991, 1992 Linux Torvalds
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>

#define MLOG_MASK_PREFIX ML_NAMEI
#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "dir.h"
#include "dlmglue.h"
#include "extent_map.h"
#include "file.h"
#include "inode.h"
#include "journal.h"
#include "namei.h"
#include "suballoc.h"
#include "uptodate.h"

#include "buffer_head_io.h"

static unsigned char ocfs2_filetype_table[] = {
        DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
};

static int ocfs2_extend_dir(struct ocfs2_super *osb,
                            struct inode *dir,
                            struct buffer_head *parent_fe_bh,
                            struct buffer_head **new_de_bh);
/*
 * ocfs2_readdir()
 *
 */
int ocfs2_readdir(struct file * filp, void * dirent, filldir_t filldir)
{
        int error = 0;
        unsigned long offset, blk, last_ra_blk = 0;
        int i, stored;
        struct buffer_head * bh, * tmp;
        struct ocfs2_dir_entry * de;
        int err;
        struct inode *inode = filp->f_path.dentry->d_inode;
        struct super_block * sb = inode->i_sb;
        unsigned int ra_sectors = 16;
        int lock_level = 0;

        mlog_entry("dirino=%llu\n",
                   (unsigned long long)OCFS2_I(inode)->ip_blkno);

        stored = 0;
        bh = NULL;

        error = ocfs2_meta_lock_atime(inode, filp->f_vfsmnt, &lock_level);
        if (lock_level && error >= 0) {
                /* We release EX lock which used to update atime
                 * and get PR lock again to reduce contention
                 * on commonly accessed directories. */
                ocfs2_meta_unlock(inode, 1);
                lock_level = 0;
                error = ocfs2_meta_lock(inode, NULL, 0);
        }
        if (error < 0) {
                if (error != -ENOENT)
                        mlog_errno(error);
                /* we haven't got any yet, so propagate the error. */
                stored = error;
                goto bail_nolock;
        }

        offset = filp->f_pos & (sb->s_blocksize - 1);

        while (!error && !stored && filp->f_pos < i_size_read(inode)) {
                blk = (filp->f_pos) >> sb->s_blocksize_bits;
                bh = ocfs2_bread(inode, blk, &err, 0);
                if (!bh) {
                        mlog(ML_ERROR,
                             "directory #%llu contains a hole at offset %lld\n",
                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
                             filp->f_pos);
                        filp->f_pos += sb->s_blocksize - offset;
                        continue;
                }

                /* The idea here is to begin with 8k read-ahead and to stay
                 * 4k ahead of our current position.
                 *
                 * TODO: Use the pagecache for this. We just need to
                 * make sure it's cluster-safe... */
                if (!last_ra_blk
                    || (((last_ra_blk - blk) << 9) <= (ra_sectors / 2))) {
                        for (i = ra_sectors >> (sb->s_blocksize_bits - 9);
                             i > 0; i--) {
                                tmp = ocfs2_bread(inode, ++blk, &err, 1);
                                if (tmp)
                                        brelse(tmp);
                        }
                        last_ra_blk = blk;
                        ra_sectors = 8;
                }

revalidate:
                /* If the dir block has changed since the last call to
                 * readdir(2), then we might be pointing to an invalid
                 * dirent right now.  Scan from the start of the block
                 * to make sure. */
                if (filp->f_version != inode->i_version) {
                        for (i = 0; i < sb->s_blocksize && i < offset; ) {
                                de = (struct ocfs2_dir_entry *) (bh->b_data + i);
                                /* It's too expensive to do a full
                                 * dirent test each time round this
                                 * loop, but we do have to test at
                                 * least that it is non-zero.  A
                                 * failure will be detected in the
                                 * dirent test below. */
                                if (le16_to_cpu(de->rec_len) <
                                    OCFS2_DIR_REC_LEN(1))
                                        break;
                                i += le16_to_cpu(de->rec_len);
                        }
                        offset = i;
                        filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
                                | offset;
                        filp->f_version = inode->i_version;
                }

                while (!error && filp->f_pos < i_size_read(inode)
                       && offset < sb->s_blocksize) {
                        de = (struct ocfs2_dir_entry *) (bh->b_data + offset);
                        if (!ocfs2_check_dir_entry(inode, de, bh, offset)) {
                                /* On error, skip the f_pos to the
                                   next block. */
                                filp->f_pos = (filp->f_pos |
                                               (sb->s_blocksize - 1)) + 1;
                                brelse(bh);
                                goto bail;
                        }
                        offset += le16_to_cpu(de->rec_len);
                        if (le64_to_cpu(de->inode)) {
                                /* We might block in the next section
                                 * if the data destination is
                                 * currently swapped out.  So, use a
                                 * version stamp to detect whether or
                                 * not the directory has been modified
                                 * during the copy operation.
                                 */
                                unsigned long version = filp->f_version;
                                unsigned char d_type = DT_UNKNOWN;

                                if (de->file_type < OCFS2_FT_MAX)
                                        d_type = ocfs2_filetype_table[de->file_type];
                                error = filldir(dirent, de->name,
                                                de->name_len,
                                                filp->f_pos,
                                                ino_from_blkno(sb, le64_to_cpu(de->inode)),
                                                d_type);
                                if (error)
                                        break;
                                if (version != filp->f_version)
                                        goto revalidate;
                                stored ++;
                        }
                        filp->f_pos += le16_to_cpu(de->rec_len);
                }
                offset = 0;
                brelse(bh);
        }

        stored = 0;
bail:
        ocfs2_meta_unlock(inode, lock_level);

bail_nolock:
        mlog_exit(stored);

        return stored;
}

/*
 * NOTE: this should always be called with parent dir i_mutex taken.
 */
int ocfs2_find_files_on_disk(const char *name,
                             int namelen,
                             u64 *blkno,
                             struct inode *inode,
                             struct buffer_head **dirent_bh,
                             struct ocfs2_dir_entry **dirent)
{
        int status = -ENOENT;

        mlog_entry("(name=%.*s, blkno=%p, inode=%p, dirent_bh=%p, dirent=%p)\n",
                   namelen, name, blkno, inode, dirent_bh, dirent);

        *dirent_bh = ocfs2_find_entry(name, namelen, inode, dirent);
        if (!*dirent_bh || !*dirent) {
                status = -ENOENT;
                goto leave;
        }

        *blkno = le64_to_cpu((*dirent)->inode);

        status = 0;
leave:
        if (status < 0) {
                *dirent = NULL;
                if (*dirent_bh) {
                        brelse(*dirent_bh);
                        *dirent_bh = NULL;
                }
        }

        mlog_exit(status);
        return status;
}

/* Check for a name within a directory.
 *
 * Return 0 if the name does not exist
 * Return -EEXIST if the directory contains the name
 *
 * Callers should have i_mutex + a cluster lock on dir
 */
int ocfs2_check_dir_for_entry(struct inode *dir,
                              const char *name,
                              int namelen)
{
        int ret;
        struct buffer_head *dirent_bh = NULL;
        struct ocfs2_dir_entry *dirent = NULL;

        mlog_entry("dir %llu, name '%.*s'\n",
                   (unsigned long long)OCFS2_I(dir)->ip_blkno, namelen, name);

        ret = -EEXIST;
        dirent_bh = ocfs2_find_entry(name, namelen, dir, &dirent);
        if (dirent_bh)
                goto bail;

        ret = 0;
bail:
        if (dirent_bh)
                brelse(dirent_bh);

        mlog_exit(ret);
        return ret;
}

/*
 * routine to check that the specified directory is empty (for rmdir)
 */
int ocfs2_empty_dir(struct inode *inode)
{
        unsigned long offset;
        struct buffer_head * bh;
        struct ocfs2_dir_entry * de, * de1;
        struct super_block * sb;
        int err;

        sb = inode->i_sb;
        if ((i_size_read(inode) <
             (OCFS2_DIR_REC_LEN(1) + OCFS2_DIR_REC_LEN(2))) ||
            !(bh = ocfs2_bread(inode, 0, &err, 0))) {
                mlog(ML_ERROR, "bad directory (dir #%llu) - no data block\n",
                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
                return 1;
        }

        de = (struct ocfs2_dir_entry *) bh->b_data;
        de1 = (struct ocfs2_dir_entry *)
                        ((char *)de + le16_to_cpu(de->rec_len));
        if ((le64_to_cpu(de->inode) != OCFS2_I(inode)->ip_blkno) ||
                        !le64_to_cpu(de1->inode) ||
                        strcmp(".", de->name) ||
                        strcmp("..", de1->name)) {
                mlog(ML_ERROR, "bad directory (dir #%llu) - no `.' or `..'\n",
                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
                brelse(bh);
                return 1;
        }
        offset = le16_to_cpu(de->rec_len) + le16_to_cpu(de1->rec_len);
        de = (struct ocfs2_dir_entry *)((char *)de1 + le16_to_cpu(de1->rec_len));
        while (offset < i_size_read(inode) ) {
                if (!bh || (void *)de >= (void *)(bh->b_data + sb->s_blocksize)) {
                        brelse(bh);
                        bh = ocfs2_bread(inode,
                                         offset >> sb->s_blocksize_bits, &err, 0);
                        if (!bh) {
                                mlog(ML_ERROR, "dir %llu has a hole at %lu\n",
                                     (unsigned long long)OCFS2_I(inode)->ip_blkno, offset);
                                offset += sb->s_blocksize;
                                continue;
                        }
                        de = (struct ocfs2_dir_entry *) bh->b_data;
                }
                if (!ocfs2_check_dir_entry(inode, de, bh, offset)) {
                        brelse(bh);
                        return 1;
                }
                if (le64_to_cpu(de->inode)) {
                        brelse(bh);
                        return 0;
                }
                offset += le16_to_cpu(de->rec_len);
                de = (struct ocfs2_dir_entry *)
                        ((char *)de + le16_to_cpu(de->rec_len));
        }
        brelse(bh);
        return 1;
}

/* returns a bh of the 1st new block in the allocation. */
int ocfs2_do_extend_dir(struct super_block *sb,
                        handle_t *handle,
                        struct inode *dir,
                        struct buffer_head *parent_fe_bh,
                        struct ocfs2_alloc_context *data_ac,
                        struct ocfs2_alloc_context *meta_ac,
                        struct buffer_head **new_bh)
{
        int status;
        int extend;
        u64 p_blkno, v_blkno;

        spin_lock(&OCFS2_I(dir)->ip_lock);
        extend = (i_size_read(dir) == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters));
        spin_unlock(&OCFS2_I(dir)->ip_lock);

        if (extend) {
                u32 offset = OCFS2_I(dir)->ip_clusters;

                status = ocfs2_do_extend_allocation(OCFS2_SB(sb), dir, &offset,
                                                    1, 0, parent_fe_bh, handle,
                                                    data_ac, meta_ac, NULL);
                BUG_ON(status == -EAGAIN);
                if (status < 0) {
                        mlog_errno(status);
                        goto bail;
                }
        }

        v_blkno = ocfs2_blocks_for_bytes(sb, i_size_read(dir));
        status = ocfs2_extent_map_get_blocks(dir, v_blkno, &p_blkno, NULL, NULL);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        *new_bh = sb_getblk(sb, p_blkno);
        if (!*new_bh) {
                status = -EIO;
                mlog_errno(status);
                goto bail;
        }
        status = 0;
bail:
        mlog_exit(status);
        return status;
}

/* assumes you already have a cluster lock on the directory. */
static int ocfs2_extend_dir(struct ocfs2_super *osb,
                            struct inode *dir,
                            struct buffer_head *parent_fe_bh,
                            struct buffer_head **new_de_bh)
{
        int status = 0;
        int credits, num_free_extents, drop_alloc_sem = 0;
        loff_t dir_i_size;
        struct ocfs2_dinode *fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
        struct ocfs2_alloc_context *data_ac = NULL;
        struct ocfs2_alloc_context *meta_ac = NULL;
        handle_t *handle = NULL;
        struct buffer_head *new_bh = NULL;
        struct ocfs2_dir_entry * de;
        struct super_block *sb = osb->sb;

        mlog_entry_void();

        dir_i_size = i_size_read(dir);
        mlog(0, "extending dir %llu (i_size = %lld)\n",
             (unsigned long long)OCFS2_I(dir)->ip_blkno, dir_i_size);

        /* dir->i_size is always block aligned. */
        spin_lock(&OCFS2_I(dir)->ip_lock);
        if (dir_i_size == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters)) {
                spin_unlock(&OCFS2_I(dir)->ip_lock);
                num_free_extents = ocfs2_num_free_extents(osb, dir, fe);
                if (num_free_extents < 0) {
                        status = num_free_extents;
                        mlog_errno(status);
                        goto bail;
                }

                if (!num_free_extents) {
                        status = ocfs2_reserve_new_metadata(osb, fe, &meta_ac);
                        if (status < 0) {
                                if (status != -ENOSPC)
                                        mlog_errno(status);
                                goto bail;
                        }
                }

                status = ocfs2_reserve_clusters(osb, 1, &data_ac);
                if (status < 0) {
                        if (status != -ENOSPC)
                                mlog_errno(status);
                        goto bail;
                }

                credits = ocfs2_calc_extend_credits(sb, fe, 1);
        } else {
                spin_unlock(&OCFS2_I(dir)->ip_lock);
                credits = OCFS2_SIMPLE_DIR_EXTEND_CREDITS;
        }

        down_write(&OCFS2_I(dir)->ip_alloc_sem);
        drop_alloc_sem = 1;

        handle = ocfs2_start_trans(osb, credits);
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                handle = NULL;
                mlog_errno(status);
                goto bail;
        }

        status = ocfs2_do_extend_dir(osb->sb, handle, dir, parent_fe_bh,
                                     data_ac, meta_ac, &new_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        ocfs2_set_new_buffer_uptodate(dir, new_bh);

        status = ocfs2_journal_access(handle, dir, new_bh,
                                      OCFS2_JOURNAL_ACCESS_CREATE);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }
        memset(new_bh->b_data, 0, sb->s_blocksize);
        de = (struct ocfs2_dir_entry *) new_bh->b_data;
        de->inode = 0;
        de->rec_len = cpu_to_le16(sb->s_blocksize);
        status = ocfs2_journal_dirty(handle, new_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        dir_i_size += dir->i_sb->s_blocksize;
        i_size_write(dir, dir_i_size);
        dir->i_blocks = ocfs2_inode_sector_count(dir);
        status = ocfs2_mark_inode_dirty(handle, dir, parent_fe_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        *new_de_bh = new_bh;
        get_bh(*new_de_bh);
bail:
        if (drop_alloc_sem)
                up_write(&OCFS2_I(dir)->ip_alloc_sem);
        if (handle)
                ocfs2_commit_trans(osb, handle);

        if (data_ac)
                ocfs2_free_alloc_context(data_ac);
        if (meta_ac)
                ocfs2_free_alloc_context(meta_ac);

        if (new_bh)
                brelse(new_bh);

        mlog_exit(status);
        return status;
}

/*
 * Search the dir for a good spot, extending it if necessary. The
 * block containing an appropriate record is returned in ret_de_bh.
 */
int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
                                 struct inode *dir,
                                 struct buffer_head *parent_fe_bh,
                                 const char *name,
                                 int namelen,
                                 struct buffer_head **ret_de_bh)
{
        unsigned long offset;
        struct buffer_head * bh = NULL;
        unsigned short rec_len;
        struct ocfs2_dinode *fe;
        struct ocfs2_dir_entry *de;
        struct super_block *sb;
        int status;

        mlog_entry_void();

        mlog(0, "getting ready to insert namelen %d into dir %llu\n",
             namelen, (unsigned long long)OCFS2_I(dir)->ip_blkno);

        BUG_ON(!S_ISDIR(dir->i_mode));
        fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
        BUG_ON(le64_to_cpu(fe->i_size) != i_size_read(dir));

        sb = dir->i_sb;

        if (!namelen) {
                status = -EINVAL;
                mlog_errno(status);
                goto bail;
        }

        bh = ocfs2_bread(dir, 0, &status, 0);
        if (!bh) {
                mlog_errno(status);
                goto bail;
        }

        rec_len = OCFS2_DIR_REC_LEN(namelen);
        offset = 0;
        de = (struct ocfs2_dir_entry *) bh->b_data;
        while (1) {
                if ((char *)de >= sb->s_blocksize + bh->b_data) {
                        brelse(bh);
                        bh = NULL;

                        if (i_size_read(dir) <= offset) {
                                status = ocfs2_extend_dir(osb,
                                                          dir,
                                                          parent_fe_bh,
                                                          &bh);
                                if (status < 0) {
                                        mlog_errno(status);
                                        goto bail;
                                }
                                BUG_ON(!bh);
                                *ret_de_bh = bh;
                                get_bh(*ret_de_bh);
                                goto bail;
                        }
                        bh = ocfs2_bread(dir,
                                         offset >> sb->s_blocksize_bits,
                                         &status,
                                         0);
                        if (!bh) {
                                mlog_errno(status);
                                goto bail;
                        }
                        /* move to next block */
                        de = (struct ocfs2_dir_entry *) bh->b_data;
                }
                if (!ocfs2_check_dir_entry(dir, de, bh, offset)) {
                        status = -ENOENT;
                        goto bail;
                }
                if (ocfs2_match(namelen, name, de)) {
                        status = -EEXIST;
                        goto bail;
                }
                if (((le64_to_cpu(de->inode) == 0) &&
                     (le16_to_cpu(de->rec_len) >= rec_len)) ||
                    (le16_to_cpu(de->rec_len) >=
                     (OCFS2_DIR_REC_LEN(de->name_len) + rec_len))) {
                        /* Ok, we found a spot. Return this bh and let
                         * the caller actually fill it in. */
                        *ret_de_bh = bh;
                        get_bh(*ret_de_bh);
                        status = 0;
                        goto bail;
                }
                offset += le16_to_cpu(de->rec_len);
                de = (struct ocfs2_dir_entry *)((char *) de + le16_to_cpu(de->rec_len));
        }

        status = 0;
bail:
        if (bh)
                brelse(bh);

        mlog_exit(status);
        return status;
}