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/*
* fs/bfs/file.c
* BFS file operations.
* Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
*/
#include <linux/fs.h>
#include <linux/locks.h>
#include <linux/bfs_fs.h>
#include <linux/smp_lock.h>
#include "bfs_defs.h"
#undef DEBUG
#ifdef DEBUG
#define dprintf(x...) printf(x)
#else
#define dprintf(x...)
#endif
struct file_operations bfs_file_operations = {
read: generic_file_read,
write: generic_file_write,
mmap: generic_file_mmap,
};
static int bfs_move_block(unsigned long from, unsigned long to, kdev_t dev)
{
struct buffer_head *bh, *new;
bh = bread(dev, from, BFS_BSIZE);
if (!bh)
return -EIO;
new = getblk(dev, to, BFS_BSIZE);
memcpy(new->b_data, bh->b_data, bh->b_size);
mark_buffer_dirty(new);
bforget(bh);
brelse(new);
return 0;
}
static int bfs_move_blocks(kdev_t dev, unsigned long start, unsigned long end,
unsigned long where)
{
unsigned long i;
dprintf("%08lx-%08lx->%08lx\n", start, end, where);
for (i = start; i <= end; i++)
if(bfs_move_block(i, where + i, dev)) {
dprintf("failed to move block %08lx -> %08lx\n", i, where + i);
return -EIO;
}
return 0;
}
static int bfs_get_block(struct inode * inode, long block,
struct buffer_head * bh_result, int create)
{
long phys;
int err;
struct super_block *sb = inode->i_sb;
struct buffer_head *sbh = sb->su_sbh;
if (block < 0 || block > sb->su_blocks)
return -EIO;
phys = inode->iu_sblock + block;
if (!create) {
if (phys <= inode->iu_eblock) {
dprintf("c=%d, b=%08lx, phys=%08lx (granted)\n", create, block, phys);
bh_result->b_dev = inode->i_dev;
bh_result->b_blocknr = phys;
bh_result->b_state |= (1UL << BH_Mapped);
}
return 0;
}
/* if the file is not empty and the requested block is within the range
of blocks allocated for this file, we can grant it */
if (inode->i_size && phys <= inode->iu_eblock) {
dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n",
create, block, phys);
bh_result->b_dev = inode->i_dev;
bh_result->b_blocknr = phys;
bh_result->b_state |= (1UL << BH_Mapped);
return 0;
}
/* the rest has to be protected against itself */
lock_kernel();
/* if the last data block for this file is the last allocated block, we can
extend the file trivially, without moving it anywhere */
if (inode->iu_eblock == sb->su_lf_eblk) {
dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n",
create, block, phys);
bh_result->b_dev = inode->i_dev;
bh_result->b_blocknr = phys;
bh_result->b_state |= (1UL << BH_Mapped);
sb->su_freeb -= phys - inode->iu_eblock;
sb->su_lf_eblk = inode->iu_eblock = phys;
mark_inode_dirty(inode);
mark_buffer_dirty(sbh);
err = 0;
goto out;
}
/* Ok, we have to move this entire file to the next free block */
phys = sb->su_lf_eblk + 1;
if (inode->iu_sblock) { /* if data starts on block 0 then there is no data */
err = bfs_move_blocks(inode->i_dev, inode->iu_sblock,
inode->iu_eblock, phys);
if (err) {
dprintf("failed to move ino=%08lx -> fs corruption\n", inode->i_ino);
goto out;
}
} else
err = 0;
dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n", create, block, phys);
inode->iu_sblock = phys;
phys += block;
sb->su_lf_eblk = inode->iu_eblock = phys;
/* this assumes nothing can write the inode back while we are here
* and thus update inode->i_blocks! (XXX)*/
sb->su_freeb -= inode->iu_eblock - inode->iu_sblock + 1 - inode->i_blocks;
mark_inode_dirty(inode);
mark_buffer_dirty(sbh);
bh_result->b_dev = inode->i_dev;
bh_result->b_blocknr = phys;
bh_result->b_state |= (1UL << BH_Mapped);
out:
unlock_kernel();
return err;
}
static int bfs_writepage(struct page *page)
{
return block_write_full_page(page, bfs_get_block);
}
static int bfs_readpage(struct file *file, struct page *page)
{
return block_read_full_page(page, bfs_get_block);
}
static int bfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
{
return block_prepare_write(page, from, to, bfs_get_block);
}
static int bfs_bmap(struct address_space *mapping, long block)
{
return generic_block_bmap(mapping, block, bfs_get_block);
}
struct address_space_operations bfs_aops = {
readpage: bfs_readpage,
writepage: bfs_writepage,
sync_page: block_sync_page,
prepare_write: bfs_prepare_write,
commit_write: generic_commit_write,
bmap: bfs_bmap,
};
struct inode_operations bfs_file_inops;
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