patch-2.4.6 linux/fs/sysv/truncate.c

• Lines: 294
• Date: Wed Dec 31 16:00:00 1969
• Orig file: v2.4.5/linux/fs/sysv/truncate.c
• Orig date: Tue Sep 5 14:07:30 2000

diff -u --recursive --new-file v2.4.5/linux/fs/sysv/truncate.c linux/fs/sysv/truncate.c
@@ -1,293 +0,0 @@
-/*
- *  linux/fs/sysv/truncate.c
- *
- *  minix/truncate.c
- *  Copyright (C) 1991, 1992  Linus Torvalds
- *
- *  coh/truncate.c
- *  Copyright (C) 1993  Pascal Haible, Bruno Haible
- *
- *  sysv/truncate.c
- *  Copyright (C) 1993  Bruno Haible
- */
-
-#include <linux/sched.h>
-#include <linux/fs.h>
-#include <linux/sysv_fs.h>
-#include <linux/stat.h>
-
-
-/* Linus' implementation of truncate.
- * It doesn't need locking because it can tell from looking at bh->b_count
- * whether a given block is in use elsewhere.
- */
-
-/*
- * Truncate has the most races in the whole filesystem: coding it is
- * a pain in the a**, especially as I don't do any locking.
- *
- * The code may look a bit weird, but that's just because I've tried to
- * handle things like file-size changes in a somewhat graceful manner.
- * Anyway, truncating a file at the same time somebody else writes to it
- * is likely to result in pretty weird behaviour...
- *
- * The new code handles normal truncates (size = 0) as well as the more
- * general case (size = XXX). I hope.
- */
-
-#define DATA_BUFFER_USED(bh) \
-	(atomic_read(&bh->b_count)>1 || buffer_locked(bh))
-
-/* We throw away any data beyond inode->i_size. */
-
-static int trunc_direct(struct inode * inode)
-{
-	struct super_block * sb;
-	unsigned int i;
-	u32 * p;
-	u32 block;
-	struct buffer_head * bh;
-	int retry = 0;
-
-	sb = inode->i_sb;
-repeat:
-	for (i = ((unsigned long) inode->i_size + sb->sv_block_size_1) >> sb->sv_block_size_bits; i < 10; i++) {
-		p = inode->u.sysv_i.i_data + i;
-		block = *p;
-		if (!block)
-			continue;
-		bh = sv_get_hash_table(sb, inode->i_dev, block);
-		if ((i << sb->sv_block_size_bits) < inode->i_size) {
-			brelse(bh);
-			goto repeat;
-		}
-		if ((bh && DATA_BUFFER_USED(bh)) || (block != *p)) {
-			retry = 1;
-			brelse(bh);
-			continue;
-		}
-		*p = 0;
-		mark_inode_dirty(inode);
-		brelse(bh);
-		sysv_free_block(sb,block);
-	}
-	return retry;
-}
-
-static int trunc_indirect(struct inode * inode, unsigned long offset, sysv_zone_t * p, int convert, unsigned char * dirt)
-{
-	unsigned long indtmp, indblock;
-	struct super_block * sb;
-	struct buffer_head * indbh;
-	unsigned int i;
-	sysv_zone_t * ind;
-	unsigned long tmp, block;
-	struct buffer_head * bh;
-	int retry = 0;
-
-	indblock = indtmp = *p;
-	if (convert)
-		indblock = from_coh_ulong(indblock);
-	if (!indblock)
-		return 0;
-	sb = inode->i_sb;
-	indbh = sv_bread(sb, inode->i_dev, indblock);
-	if (indtmp != *p) {
-		brelse(indbh);
-		return 1;
-	}
-	if (!indbh) {
-		*p = 0;
-		*dirt = 1;
-		return 0;
-	}
-repeat:
-	if (inode->i_size < offset)
-		i = 0;
-	else
-		i = (inode->i_size - offset + sb->sv_block_size_1) >> sb->sv_block_size_bits;
-	for (; i < sb->sv_ind_per_block; i++) {
-		ind = ((sysv_zone_t *) indbh->b_data) + i;
-		block = tmp = *ind;
-		if (sb->sv_convert)
-			block = from_coh_ulong(block);
-		if (!block)
-			continue;
-		bh = sv_get_hash_table(sb, inode->i_dev, block);
-		if ((i << sb->sv_block_size_bits) + offset < inode->i_size) {
-			brelse(bh);
-			goto repeat;
-		}
-		if ((bh && DATA_BUFFER_USED(bh)) || (tmp != *ind)) {
-			retry = 1;
-			brelse(bh);
-			continue;
-		}
-		*ind = 0;
-		mark_buffer_dirty(indbh);
-		brelse(bh);
-		sysv_free_block(sb,block);
-	}
-	for (i = 0; i < sb->sv_ind_per_block; i++)
-		if (((sysv_zone_t *) indbh->b_data)[i])
-			goto done;
-	if (DATA_BUFFER_USED(indbh) || (indtmp != *p)) {
-		brelse(indbh);
-		return 1;
-	}
-	*p = 0;
-	*dirt = 1;
-	sysv_free_block(sb,indblock);
-done:
-	brelse(indbh);
-	return retry;
-}
-
-static int trunc_dindirect(struct inode * inode, unsigned long offset, sysv_zone_t * p, int convert, unsigned char * dirt)
-{
-	u32 indtmp, indblock;
-	struct super_block * sb;
-	struct buffer_head * indbh;
-	unsigned int i;
-	sysv_zone_t * ind;
-	u32 tmp, block;
-	int retry = 0;
-
-	indblock = indtmp = *p;
-	if (convert)
-		indblock = from_coh_ulong(indblock);
-	if (!indblock)
-		return 0;
-	sb = inode->i_sb;
-	indbh = sv_bread(sb, inode->i_dev, indblock);
-	if (indtmp != *p) {
-		brelse(indbh);
-		return 1;
-	}
-	if (!indbh) {
-		*p = 0;
-		*dirt = 1;
-		return 0;
-	}
-	if (inode->i_size < offset)
-		i = 0;
-	else
-		i = (inode->i_size - offset + sb->sv_ind_per_block_block_size_1) >> sb->sv_ind_per_block_block_size_bits;
-	for (; i < sb->sv_ind_per_block; i++) {
-		unsigned char dirty = 0;
-		ind = ((sysv_zone_t *) indbh->b_data) + i;
-		block = tmp = *ind;
-		if (sb->sv_convert)
-			block = from_coh_ulong(block);
-		if (!block)
-			continue;
-		retry |= trunc_indirect(inode,offset+(i<<sb->sv_ind_per_block_bits),ind,sb->sv_convert,&dirty);
-		if (dirty)
-			mark_buffer_dirty(indbh);
-	}
-	for (i = 0; i < sb->sv_ind_per_block; i++)
-		if (((sysv_zone_t *) indbh->b_data)[i])
-			goto done;
-	if (DATA_BUFFER_USED(indbh) || (indtmp != *p)) {
-		brelse(indbh);
-		return 1;
-	}
-	*p = 0;
-	*dirt = 1;
-	sysv_free_block(sb,indblock);
-done:
-	brelse(indbh);
-	return retry;
-}
-
-static int trunc_tindirect(struct inode * inode, unsigned long offset, sysv_zone_t * p, int convert, unsigned char * dirt)
-{
-	u32 indtmp, indblock;
-	struct super_block * sb;
-	struct buffer_head * indbh;
-	unsigned int i;
-	sysv_zone_t * ind;
-	u32 tmp, block;
-	int retry = 0;
-
-	indblock = indtmp = *p;
-	if (convert)
-		indblock = from_coh_ulong(indblock);
-	if (!indblock)
-		return 0;
-	sb = inode->i_sb;
-	indbh = sv_bread(sb, inode->i_dev, indblock);
-	if (indtmp != *p) {
-		brelse(indbh);
-		return 1;
-	}
-	if (!indbh) {
-		*p = 0;
-		*dirt = 1;
-		return 0;
-	}
-	if (inode->i_size < offset)
-		i = 0;
-	else
-		i = (inode->i_size - offset + sb->sv_ind_per_block_2_block_size_1) >> sb->sv_ind_per_block_2_block_size_bits;
-	for (; i < sb->sv_ind_per_block; i++) {
-		unsigned char dirty = 0;
-		ind = ((sysv_zone_t *) indbh->b_data) + i;
-		block = tmp = *ind;
-		if (sb->sv_convert)
-			block = from_coh_ulong(block);
-		if (!block)
-			continue;
-		retry |= trunc_dindirect(inode,offset+(i<<sb->sv_ind_per_block_2_bits),ind,sb->sv_convert,&dirty);
-		if (dirty)
-			mark_buffer_dirty(indbh);
-	}
-	for (i = 0; i < sb->sv_ind_per_block; i++)
-		if (((sysv_zone_t *) indbh->b_data)[i])
-			goto done;
-	if (DATA_BUFFER_USED(indbh) || (indtmp != *p)) {
-		brelse(indbh);
-		return 1;
-	}
-	*p = 0;
-	*dirt = 1;
-	sysv_free_block(sb,indblock);
-done:
-	brelse(indbh);
-	return retry;
-}
-
-static int trunc_all(struct inode * inode)
-{
-	struct super_block * sb;
-	char dirty;
-
-	sb = inode->i_sb;
-	return trunc_direct(inode)
-	     | trunc_indirect(inode,sb->sv_ind0_size,&inode->u.sysv_i.i_data[10],0,&dirty)
-	     | trunc_dindirect(inode,sb->sv_ind1_size,&inode->u.sysv_i.i_data[11],0,&dirty)
-	     | trunc_tindirect(inode,sb->sv_ind2_size,&inode->u.sysv_i.i_data[12],0,&dirty);
-}
-
-
-void sysv_truncate(struct inode * inode)
-{
-	/* If this is called from sysv_put_inode, we needn't worry about
-	 * races as we are just losing the last reference to the inode.
-	 * If this is called from another place, let's hope it's a regular
-	 * file.
-	 * Truncating symbolic links is strange. We assume we don't truncate
-	 * a directory we are just modifying. We ensure we don't truncate
-	 * a regular file we are just writing to, by use of a lock.
-	 */
-	if (S_ISLNK(inode->i_mode))
-		printk("sysv_truncate: truncating symbolic link\n");
-	else if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
-		return;
-	while (trunc_all(inode)) {
-		current->counter = 0;
-		schedule();
-	}
-	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
-	mark_inode_dirty(inode);
-}