linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * QNX6 file system, Linux implementation.

 *

 * Version : 1.0.0

 *

 * History :

 *

 * 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release.

 * 16-02-2012 pagemap extension by Al Viro

 *

 */

​

#include "qnx6.h"

​

static unsigned qnx6_lfile_checksum(char *name, unsigned size)

{

    unsigned crc = 0;

    char *end = name + size;

    while (name < end) {

        crc = ((crc >> 1) + *(name++)) ^

            ((crc & 0x00000001) ? 0x80000000 : 0);

    }

    return crc;

}

​

static struct page *qnx6_get_page(struct inode *dir, unsigned long n)

{

    struct address_space *mapping = dir->i_mapping;

    struct page *page = read_mapping_page(mapping, n, NULL);

    if (!IS_ERR(page))

        kmap(page);

    return page;

}

​

static unsigned last_entry(struct inode *inode, unsigned long page_nr)

{

    unsigned long last_byte = inode->i_size;

    last_byte -= page_nr << PAGE_SHIFT;

    if (last_byte > PAGE_SIZE)

        last_byte = PAGE_SIZE;

    return last_byte / QNX6_DIR_ENTRY_SIZE;

}

​

static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,

                     struct qnx6_long_dir_entry *de,

                     struct page **p)

{

    struct qnx6_sb_info *sbi = QNX6_SB(sb);

    u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */

    u32 n = s >> (PAGE_SHIFT - sb->s_blocksize_bits); /* in pages */

    /* within page */

    u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_MASK;

    struct address_space *mapping = sbi->longfile->i_mapping;

    struct page *page = read_mapping_page(mapping, n, NULL);

    if (IS_ERR(page))

        return ERR_CAST(page);

    kmap(*p = page);

    return (struct qnx6_long_filename *)(page_address(page) + offs);

}

​

static int qnx6_dir_longfilename(struct inode *inode,

            struct qnx6_long_dir_entry *de,

            struct dir_context *ctx,

            unsigned de_inode)

{

    struct qnx6_long_filename *lf;

    struct super_block *s = inode->i_sb;

    struct qnx6_sb_info *sbi = QNX6_SB(s);

    struct page *page;

    int lf_size;

​

    if (de->de_size != 0xff) {

        /* error - long filename entries always have size 0xff

           in direntry */

        pr_err("invalid direntry size (%i).\n", de->de_size);

        return 0;

    }

    lf = qnx6_longname(s, de, &page);

    if (IS_ERR(lf)) {

        pr_err("Error reading longname\n");

        return 0;

    }

​

    lf_size = fs16_to_cpu(sbi, lf->lf_size);

​

    if (lf_size > QNX6_LONG_NAME_MAX) {

        pr_debug("file %s\n", lf->lf_fname);

        pr_err("Filename too long (%i)\n", lf_size);

        qnx6_put_page(page);

        return 0;

    }