file.c

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/*
 *  linux/fs/hpfs/file.c
 *
 *  Mikulas Patocka ([email protected]), 1998-1999
 *
 *  file VFS functions
 */

#include "hpfs_fn.h"

#define BLOCKS(size) (((size) + 511) >> 9)

static int hpfs_file_release(struct inode *inode, struct file *file)
{
    hpfs_lock(inode->i_sb);
    hpfs_write_if_changed(inode);
    hpfs_unlock(inode->i_sb);
    return 0;
}

int hpfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
    struct inode *inode = file->f_mapping->host;
    int ret;

    ret = filemap_write_and_wait_range(file->f_mapping, start, end);
    if (ret)
        return ret;
    return sync_blockdev(inode->i_sb->s_bdev);
}

/*
 * generic_file_read often calls bmap with non-existing sector,
 * so we must ignore such errors.
 */

static secno hpfs_bmap(struct inode *inode, unsigned file_secno)
{
    struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
    unsigned n, disk_secno;
    struct fnode *fnode;
    struct buffer_head *bh;
    if (BLOCKS(hpfs_i(inode)->mmu_private) <= file_secno) return 0;
    n = file_secno - hpfs_inode->i_file_sec;
    if (n < hpfs_inode->i_n_secs) return hpfs_inode->i_disk_sec + n;
    if (!(fnode = hpfs_map_fnode(inode->i_sb, inode->i_ino, &bh))) return 0;
    disk_secno = hpfs_bplus_lookup(inode->i_sb, inode, &fnode->btree, file_secno, bh);
    if (disk_secno == -1) return 0;
    if (hpfs_chk_sectors(inode->i_sb, disk_secno, 1, "bmap")) return 0;
    return disk_secno;
}

static void hpfs_truncate(struct inode *i)
{
    if (IS_IMMUTABLE(i)) return /*-EPERM*/;
    hpfs_lock_assert(i->i_sb);

    hpfs_i(i)->i_n_secs = 0;
    i->i_blocks = 1 + ((i->i_size + 511) >> 9);
    hpfs_i(i)->mmu_private = i->i_size;
    hpfs_truncate_btree(i->i_sb, i->i_ino, 1, ((i->i_size + 511) >> 9));
    hpfs_write_inode(i);
    hpfs_i(i)->i_n_secs = 0;
}

static int hpfs_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
{
    int r;
    secno s;
    hpfs_lock(inode->i_sb);
    s = hpfs_bmap(inode, iblock);
    if (s) {
        map_bh(bh_result, inode->i_sb, s);
        goto ret_0;
    }
    if (!create) goto ret_0;
    if (iblock<<9 != hpfs_i(inode)->mmu_private) {
        BUG();
        r = -EIO;
        goto ret_r;
    }
    if ((s = hpfs_add_sector_to_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1)) == -1) {
        hpfs_truncate_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1);
        r = -ENOSPC;
        goto ret_r;
    }
    inode->i_blocks++;
    hpfs_i(inode)->mmu_private += 512;
    set_buffer_new(bh_result);
    map_bh(bh_result, inode->i_sb, s);
    ret_0:
    r = 0;
    ret_r:
    hpfs_unlock(inode->i_sb);
    return r;
}

static int hpfs_writepage(struct page *page, struct writeback_control *wbc)
{
    return block_write_full_page(page,hpfs_get_block, wbc);
}

static int hpfs_readpage(struct file *file, struct page *page)
{
    return block_read_full_page(page,hpfs_get_block);
}

static int hpfs_write_begin(struct file *file, struct address_space *mapping,
            loff_t pos, unsigned len, unsigned flags,
            struct page **pagep, void **fsdata)
{
    int ret;

    *pagep = NULL;
    ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
                hpfs_get_block,
                &hpfs_i(mapping->host)->mmu_private);
    if (unlikely(ret)) {
        loff_t isize = mapping->host->i_size;
        if (pos + len > isize)
            vmtruncate(mapping->host, isize);
    }

    return ret;
}

static sector_t _hpfs_bmap(struct address_space *mapping, sector_t block)
{
    return generic_block_bmap(mapping,block,hpfs_get_block);
}

const struct address_space_operations hpfs_aops = {
    .readpage = hpfs_readpage,
    .writepage = hpfs_writepage,
    .write_begin = hpfs_write_begin,
    .write_end = generic_write_end,
    .bmap = _hpfs_bmap
};

static ssize_t hpfs_file_write(struct file *file, const char __user *buf,
            size_t count, loff_t *ppos)
{
    ssize_t retval;

    retval = do_sync_write(file, buf, count, ppos);
    if (retval > 0) {
        hpfs_lock(file->f_path.dentry->d_sb);
        hpfs_i(file->f_path.dentry->d_inode)->i_dirty = 1;
        hpfs_unlock(file->f_path.dentry->d_sb);
    }
    return retval;
}

const struct file_operations hpfs_file_ops =
{
    .llseek     = generic_file_llseek,
    .read       = do_sync_read,
    .aio_read   = generic_file_aio_read,
    .write      = hpfs_file_write,
    .aio_write  = generic_file_aio_write,
    .mmap       = generic_file_mmap,
    .release    = hpfs_file_release,
    .fsync      = hpfs_file_fsync,
    .splice_read    = generic_file_splice_read,
};

const struct inode_operations hpfs_file_iops =
{
    .truncate   = hpfs_truncate,
    .setattr    = hpfs_setattr,
};