path: root/fs/affs/file.c

/*
 *  linux/fs/affs/file.c
 *
 *  (c) 1996  Hans-Joachim Widmaier - Rewritten
 *
 *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
 *
 *  (C) 1992  Eric Youngdale Modified for ISO 9660 filesystem.
 *
 *  (C) 1991  Linus Torvalds - minix filesystem
 *
 *  affs regular file handling primitives
 */

#include <linux/uio.h>
#include "affs.h"

static struct buffer_head *affs_get_extblock_slow(struct inode *inode, u32 ext);

static int
affs_file_open(struct inode *inode, struct file *filp)
{
	pr_debug("open(%lu,%d)\n",
		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));
	atomic_inc(&AFFS_I(inode)->i_opencnt);
	return 0;
}

static int
affs_file_release(struct inode *inode, struct file *filp)
{
	pr_debug("release(%lu, %d)\n",
		 inode->i_ino, atomic_read(&AFFS_I(inode)->i_opencnt));

	if (atomic_dec_and_test(&AFFS_I(inode)->i_opencnt)) {
		mutex_lock(&inode->i_mutex);
		if (inode->i_size != AFFS_I(inode)->mmu_private)
			affs_truncate(inode);
		affs_free_prealloc(inode);
		mutex_unlock(&inode->i_mutex);
	}

	return 0;
}

static int
affs_grow_extcache(struct inode *inode, u32 lc_idx)
{
	struct super_block	*sb = inode->i_sb;
	struct buffer_head	*bh;
	u32 lc_max;
	int i, j, key;

	if (!AFFS_I(inode)->i_lc) {
		char *ptr = (char *)get_zeroed_page(GFP_NOFS);
		if (!ptr)
			return -ENOMEM;
		AFFS_I(inode)->i_lc = (u32 *)ptr;
		AFFS_I(inode)->i_ac = (struct affs_ext_key *)(ptr + AFFS_CACHE_SIZE / 2);
	}

	lc_max = AFFS_LC_SIZE << AFFS_I(inode)->i_lc_shift;

	if (AFFS_I(inode)->i_extcnt > lc_max) {
		u32 lc_shift, lc_mask, tmp, off;

		/* need to recalculate linear cache, start from old size */
		lc_shift = AFFS_I(inode)->i_lc_shift;
		tmp = (AFFS_I(inode)->i_extcnt / AFFS_LC_SIZE) >> lc_shift;
		for (; tmp; tmp >>= 1)
			lc_shift++;
		lc_mask = (1 << lc_shift) - 1;

		/* fix idx and old size to new shift */
		lc_idx >>= (lc_shift - AFFS_I(inode)->i_lc_shift);
		AFFS_I(inode)->i_lc_size >>= (lc_shift - AFFS_I(inode)->i_lc_shift);

		/* first shrink old cache to make more space */
		off = 1 << (lc_shift - AFFS_I(inode)->i_lc_shift);
		for (i = 1, j = off; j < AFFS_LC_SIZE; i++, j += off)
			AFFS_I(inode)->i_ac[i] = AFFS_I(inode)->i_ac[j];

		AFFS_I(inode)->i_lc_shift = lc_shift;
		AFFS_I(inode)->i_lc_mask = lc_mask;
	}

	/* fill cache to the needed index */
	i = AFFS_I(inode)->i_lc_size;
	AFFS_I(inode)->i_lc_size = lc_idx + 1;
	for (; i <= lc_idx; i++) {
		if (!i) {
			AFFS_I(inode)->i_lc[0] = inode->i_ino;
			continue;
		}
		key = AFFS_I(inode)->i_lc[i - 1];
		j = AFFS_I(inode)->i_lc_mask + 1;
		// unlock cache
		for (; j > 0; j--) {
			bh = affs_bread(sb, key);
			if (!bh)
				goto err;
			key = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
			affs_brelse(bh);
		}
		// lock cache
		AFFS_I(inode)->i_lc[i] = key;
	}

	return 0;

err:
	// lock cache
	return -EIO;
}

static struct buffer_head *
affs_alloc_extblock(struct inode *inode, struct buffer_head *bh, u32 ext)
{
	struct super_block *sb = inode->i_sb;
	struct buffer_head *new_bh;
	u32 blocknr, tmp;

	blocknr = affs_alloc_block(inode, bh->b_blocknr);
	if (!blocknr)
		return ERR_PTR(-ENOSPC);

	new_bh = affs_getzeroblk(sb, blocknr);
	if (!new_bh) {
		affs_free_block(sb, blocknr);
		return ERR_PTR(-EIO);
	}

	AFFS_HEAD(new_bh)->ptype = cpu_to_be32(T_LIST);
	AFFS_HEAD(new_bh)->key = cpu_to_be32(blocknr);
	AFFS_TAIL(sb, new_bh)->stype = cpu_to_be32(ST_FILE);
	AFFS_TAIL(sb, new_bh)->parent = cpu_to_be32(inode->i_ino);
	affs_fix_checksum(sb, new_bh);

	mark_buffer_dirty_inode(new_bh, inode);

	tmp = be32_to_cpu(AFFS_TAIL(sb, bh)->extension);
	if (tmp)
		affs_warning(sb, "alloc_ext", "previous extension set (%x)", tmp);
	AFFS_TAIL(sb, bh)->extension = cpu_to_be32(blocknr);
	affs_adjust_checksum(bh, blocknr - tmp);
	mark_buffer_dirty_inode(bh, inode);

	AFFS_I(inode)->i_extcnt++;
	mark_inode_dirty(inode);

	return new_bh;
}

static inline struct buffer_head *
affs_get_extblock(struct inode *inode,