linux-zen-server/fs/ufs/inode.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/ufs/inode.c
 *
 * Copyright (C) 1998
 * Daniel Pirkl <daniel.pirkl@email.cz>
 * Charles University, Faculty of Mathematics and Physics
 *
 *  from
 *
 *  linux/fs/ext2/inode.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/inode.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Goal-directed block allocation by Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
 */

#include <linux/uaccess.h>

#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/iversion.h>

#include "ufs_fs.h"
#include "ufs.h"
#include "swab.h"
#include "util.h"

static int ufs_block_to_path(struct inode *inode, sector_t i_block, unsigned offsets[4])
{
	struct ufs_sb_private_info *uspi = UFS_SB(inode->i_sb)->s_uspi;
	int ptrs = uspi->s_apb;
	int ptrs_bits = uspi->s_apbshift;
	const long direct_blocks = UFS_NDADDR,
		indirect_blocks = ptrs,
		double_blocks = (1 << (ptrs_bits * 2));
	int n = 0;


	UFSD("ptrs=uspi->s_apb = %d,double_blocks=%ld \n",ptrs,double_blocks);
	if (i_block < direct_blocks) {
		offsets[n++] = i_block;
	} else if ((i_block -= direct_blocks) < indirect_blocks) {
		offsets[n++] = UFS_IND_BLOCK;
		offsets[n++] = i_block;
	} else if ((i_block -= indirect_blocks) < double_blocks) {
		offsets[n++] = UFS_DIND_BLOCK;
		offsets[n++] = i_block >> ptrs_bits;
		offsets[n++] = i_block & (ptrs - 1);
	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
		offsets[n++] = UFS_TIND_BLOCK;
		offsets[n++] = i_block >> (ptrs_bits * 2);
		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
		offsets[n++] = i_block & (ptrs - 1);
	} else {
		ufs_warning(inode->i_sb, "ufs_block_to_path", "block > big");
	}
	return n;
}

typedef struct {
	void	*p;
	union {
		__fs32	key32;
		__fs64	key64;
	};
	struct buffer_head *bh;
} Indirect;

static inline int grow_chain32(struct ufs_inode_info *ufsi,
			       struct buffer_head *bh, __fs32 *v,
			       Indirect *from, Indirect *to)
{
	Indirect *p;
	unsigned seq;
	to->bh = bh;
	do {
		seq = read_seqbegin(&ufsi->meta_lock);
		to->key32 = *(__fs32 *)(to->p = v);
		for (p = from; p <= to && p->key32 == *(__fs32 *)p->p; p++)
			;
	} while (read_seqretry(&ufsi->meta_lock, seq));
	return (p > to);
}

static inline int grow_chain64(struct ufs_inode_info *ufsi,
			       struct buffer_head *bh, __fs64 *v,
			       Indirect *from, Indirect *to)
{
	Indirect *p;
	unsigned seq;
	to->bh = bh;
	do {
		seq = read_seqbegin(&ufsi->meta_lock);
		to->key64 = *(__fs64 *)(to->p = v);
		for (p = from; p <= to && p->key64 == *(__fs64 *)p->p; p++)
			;
	} while (read_seqretry(&ufsi->meta_lock, seq));
	return (p > to);
}

/*
 * Returns the location of the fragment from
 * the beginning of the filesystem.
 */

static u64 ufs_frag_map(struct inode *inode, unsigned offsets[4], int depth)
{
	struct ufs_inode_info *ufsi = UFS_I(inode);
	struct super_block *sb = inode->i_sb;
	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
	u64 mask = (u64) uspi->s_apbmask>>uspi->s_fpbshift;
	int shift = uspi->s_apbshift-uspi->s_fpbshift;
	Indirect chain[4], *q = chain;
	unsigned *p;
	unsigned flags = UFS_SB(sb)->s_flags;
	u64 res = 0;

	UFSD(": uspi->s_fpbshift = %d ,uspi->s_apbmask = %x, mask=%llx\n",
		uspi->s_fpbshift, uspi->s_apbmask,
		(unsigned long long)mask);

	if (depth == 0)
		goto no_block;

again:
	p = offsets;

	if ((flags & UFS_TYPE_MASK) == UFS_TYPE_UFS2)
		goto ufs2;

	if (!grow_chain32(ufsi, NULL, &ufsi->i_u1.i_data[*p++], chain, q))
		goto changed;
	if (!q->key32)
		goto no_block;
	while (--depth) {
		__fs32 *ptr;
		struct buffer_head *bh;
		unsigned n = *p++;

		bh = sb_bread(sb, uspi->s_sbbase +
				  fs32_to_cpu(sb, q->key32) + (n>>shift));
		if (!bh)
			goto no_block;
		ptr = (__fs32 *)bh->b_data + (n & mask);
		if (!grow_chain32(ufsi, bh, ptr, chain, ++q))
			goto changed;
		if (!q->key32)
			goto no_block;
	}
	res = fs32_to_cpu(sb, q->key32);
	goto found;

ufs2:
	if (!grow_chain64(ufsi, NULL, &ufsi->i_u1.u2_i_data[*p++], chain, q))
		goto changed;
	if (!q->key64)
		goto no_block;

	while (--depth) {
		__fs64 *ptr;
		struct buffer_head *bh;
		unsigned n = *p++;

		bh = sb_bread(sb, uspi->s_sbbase +
				  fs64_to_cpu(sb, q->key64) + (n>>shift));
		if (!bh)
			goto no_block;
		ptr = (__fs64 *)bh->b_data + (n & mask);
		if (!grow_chain64(ufsi, bh, ptr, chain, ++q))
			goto changed;
		if (!q->key64)
			goto no_block;
	}
	res = fs64_to_cpu(sb, q->key64);
found:
	res += uspi->s_sbbase;
no_block:
	while (q > chain) {
		brelse(q->bh);
		q--;
	}
	return res;

changed:
	while (q > chain) {
		brelse(q->bh);
		q--;
	}
	goto again;
}

/*
 * Unpacking tails: we have a file with partial final block and
 * we had been asked to extend it.  If the fragment being written
 * is within the same block, we need to extend the tail just to cover
 * that fragment.  Otherwise the tail is extended to full block.
 *
 * Note that we might need to create a _new_ tail, but that will
 * be handled elsewhere; this is strictly for resizing old
 * ones.
 */
static bool
ufs_extend_tail(struct inode *inode, u64 writes_to,
		  int *err, struct page *locked_page)
{
	struct ufs_inode_info *ufsi = UFS_I(inode);
	struct super_block *sb = inode->i_sb;
	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
	unsigned lastfrag = ufsi->i_lastfrag;	/* it's a short file, so unsigned is enough */
	unsigned block = ufs_fragstoblks(lastfrag);
	unsigned new_size;
	void *p;
	u64 tmp;

	if (writes_to < (lastfrag | uspi->s_fpbmask))
		new_size = (writes_to & uspi->s_fpbmask) + 1;
	else
		new_size = uspi->s_fpb;

	p = ufs_get_direct_data_ptr(uspi, ufsi, block);
	tmp = ufs_new_fragments(inode, p, lastfrag, ufs_data_ptr_to_cpu(sb, p),
				new_size - (lastfrag & uspi->s_fpbmask), err,
				locked_page);
	return tmp != 0;
}

/**
 * ufs_inode_getfrag() - allocate new fragment(s)
 * @inode: pointer to inode
 * @index: number of block pointer within the inode's array.
 * @new_fragment: number of new allocated fragment(s)
 * @err: we set it if something wrong
 * @new: we set it if we allocate new block
 * @locked_page: for ufs_new_fragments()
 */
static u64
ufs_inode_getfrag(struct inode *inode, unsigned index,
		  sector_t new_fragment, int *err,
		  int *new, struct page *locked_page)
{
	struct ufs_inode_info *ufsi = UFS_I(inode);
	struct super_block *sb = inode->i_sb;
	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
	u64 tmp, goal, lastfrag;
	unsigned nfrags = uspi->s_fpb;
	void *p;

        /* TODO : to be done for write support
        if ( (flags & UFS_TYPE_MASK) == UFS_TYPE_UFS2)
             goto ufs2;
         */

	p = ufs_get_direct_data_ptr(uspi, ufsi, index);
	tmp = ufs_data_ptr_to_cpu(sb, p);
	if (tmp)
		goto out;

	lastfrag = ufsi->i_lastfrag;

	/* will that be a new tail? */
	if (new_fragment < UFS_NDIR_FRAGMENT && new_fragment >= lastfrag)
		nfrags = (new_fragment & uspi->s_fpbmask) + 1;

	goal = 0;
	if (index) {
		goal = ufs_data_ptr_to_cpu(sb,
				 ufs_get_direct_data_ptr(uspi, ufsi, index - 1));
		if (goal)
			goal += uspi->s_fpb;
	}
	tmp = ufs_new_fragments(inode, p, ufs_blknum(new_fragment),
				goal, nfrags, err, locked_page);

	if (!tmp) {
		*err = -ENOSPC;
		return 0;
	}

	if (new)
		*new = 1;
	inode->i_ctime = current_time(inode);
	if (IS_SYNC(inode))
		ufs_sync_inode (inode);
	mark_inode_dirty(inode);
out:
	return tmp + uspi->s_sbbase;

     /* This part : To be implemented ....
        Required only for writing, not required for READ-ONLY.
ufs2:

	u2_block = ufs_fragstoblks(fragment);
	u2_blockoff = ufs_fragnum(fragment);
	p = ufsi->i_u1.u2_i_data + block;
	goal = 0;

repeat2:
	tmp = fs32_to_cpu(sb, *p);
	lastfrag = ufsi->i_lastfrag;

     */
}

/**
 * ufs_inode_getblock() - allocate new block
 * @inode: pointer to inode
 * @ind_block: block number of the indirect block
 * @index: number of pointer within the indirect block
 * @new_fragment: number of new allocated fragment
 *  (block will hold this fragment and also uspi->s_fpb-1)
 * @err: see ufs_inode_getfrag()
 * @new: see ufs_inode_getfrag()
 * @locked_page: see ufs_inode_getfrag()
 */
static u64
ufs_inode_getblock(struct inode *inode, u64 ind_block,
		  unsigned index, sector_t new_fragment, int *err,
		  int *new, struct page *locked_page)
{
	struct super_block *sb = inode->i_sb;
	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
	int shift = uspi->s_apbshift - uspi->s_fpbshift;
	u64 tmp = 0, goal;
	struct buffer_head *bh;
	void *p;

	if (!ind_block)
		return 0;

	bh = sb_bread(sb, ind_block + (index >> shift));
	if (unlikely(!bh)) {
		*err = -EIO;
		return 0;
	}

	index &= uspi->s_apbmask >> uspi->s_fpbshift;
	if (uspi->fs_magic == UFS2_MAGIC)
		p = (__fs64 *)bh->b_data + index;
	else
		p = (__fs32 *)bh->b_data + index;

	tmp = ufs_data_ptr_to_cpu(sb, p);
	if (tmp)
		goto out;

	if (index && (uspi->fs_magic == UFS2_MAGIC ?
		      (tmp = fs64_to_cpu(sb, ((__fs64 *)bh->b_data)[index-1])) :
		      (tmp = fs32_to_cpu(sb, ((__fs32 *)bh->b_data)[index-1]))))
		goal = tmp + uspi->s_fpb;
	else
		goal = bh->b_blocknr + uspi->s_fpb;
	tmp = ufs_new_fragments(inode, p, ufs_blknum(new_fragment), goal,
				uspi->s_fpb, err, locked_page);
	if (!tmp)
		goto out;

	if (new)
		*new = 1;

	mark_buffer_dirty(bh);
	if (IS_SYNC(inode))
		sync_dirty_buffer(bh);
	inode->i_ctime = current_time(inode);
	mark_inode_dirty(inode);
out:
	brelse (bh);
	UFSD("EXIT\n");
	if (tmp)
		tmp += uspi->s_sbbase;
	return tmp;
}

/**
 * ufs_getfrag_block() - `get_block_t' function, interface between UFS and
 * read_folio, writepage and so on
 */

static int ufs_getfrag_block(struct inode *inode, sector_t fragment, struct buffer_head *bh_result, int create)
{
	struct super_block *sb = inode->i_sb;
	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
	int err = 0, new = 0;
	unsigned offsets[4];
	int depth = ufs_block_to_path(inode, fragment >> uspi->s_fpbshift, offsets);
	u64 phys64 = 0;
	unsigned frag = fragment & uspi->s_fpbmask;

	phys64 = ufs_frag_map(inode, offsets, depth);
	if (!create)
		goto done;

	if (phys64) {
		if (fragment >= UFS_NDIR_FRAGMENT)
			goto done;
		read_seqlock_excl(&UFS_I(inode)->meta_lock);
		if (fragment < UFS_I(inode)->i_lastfrag) {
			read_sequnlock_excl(&UFS_I(inode)->meta_lock);
			goto done;
		}
		read_sequnlock_excl(&UFS_I(inode)->meta_lock);
	}
        /* This code entered only while writing ....? */

	mutex_lock(&UFS_I(inode)->truncate_mutex);

	UFSD("ENTER, ino %lu, fragment %llu\n", inode->i_ino, (unsigned long long)fragment);
	if (unlikely(!depth)) {
		ufs_warning(sb, "ufs_get_block", "block > big");
		err = -EIO;
		goto out;
	}

	if (UFS_I(inode)->i_lastfrag < UFS_NDIR_FRAGMENT) {
		unsigned lastfrag = UFS_I(inode)->i_lastfrag;
		unsigned tailfrags = lastfrag &