/*
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/*
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* linux/fs/ext/truncate.c
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* linux/fs/ext/truncate.c
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*
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*
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* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
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* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
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*
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*
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* from
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* from
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*
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*
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* linux/fs/minix/truncate.c
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* linux/fs/minix/truncate.c
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*
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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*/
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#include <linux/sched.h>
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#include <linux/sched.h>
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#include <linux/ext_fs.h>
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#include <linux/ext_fs.h>
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#include <linux/stat.h>
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#include <linux/stat.h>
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#include <linux/fcntl.h>
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#include <linux/fcntl.h>
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#include <linux/errno.h>
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#include <linux/errno.h>
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/*
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/*
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* Truncate has the most races in the whole filesystem: coding it is
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* Truncate has the most races in the whole filesystem: coding it is
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* a pain in the a**. Especially as I don't do any locking...
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* a pain in the a**. Especially as I don't do any locking...
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*
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*
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* The code may look a bit weird, but that's just because I've tried to
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* The code may look a bit weird, but that's just because I've tried to
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* handle things like file-size changes in a somewhat graceful manner.
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* handle things like file-size changes in a somewhat graceful manner.
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* Anyway, truncating a file at the same time somebody else writes to it
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* Anyway, truncating a file at the same time somebody else writes to it
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* is likely to result in pretty weird behaviour...
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* is likely to result in pretty weird behaviour...
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*
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*
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* The new code handles normal truncates (size = 0) as well as the more
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* The new code handles normal truncates (size = 0) as well as the more
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* general case (size = XXX). I hope.
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* general case (size = XXX). I hope.
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*/
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*/
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static int trunc_direct(struct inode * inode)
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static int trunc_direct(struct inode * inode)
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{
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{
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int i, tmp;
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int i, tmp;
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unsigned long * p;
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unsigned long * p;
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struct buffer_head * bh;
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struct buffer_head * bh;
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int retry = 0;
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int retry = 0;
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#define DIRECT_BLOCK ((inode->i_size + 1023) >> 10)
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#define DIRECT_BLOCK ((inode->i_size + 1023) >> 10)
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repeat:
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repeat:
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for (i = DIRECT_BLOCK ; i < 9 ; i++) {
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for (i = DIRECT_BLOCK ; i < 9 ; i++) {
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p = inode->u.ext_i.i_data+i;
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p = inode->u.ext_i.i_data+i;
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if (!(tmp = *p))
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if (!(tmp = *p))
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continue;
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continue;
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bh = getblk(inode->i_dev,tmp,BLOCK_SIZE);
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bh = getblk(inode->i_dev,tmp,BLOCK_SIZE);
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if (i < DIRECT_BLOCK) {
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if (i < DIRECT_BLOCK) {
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brelse(bh);
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brelse(bh);
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goto repeat;
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goto repeat;
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}
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}
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if ((bh && bh->b_count != 1) || tmp != *p) {
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if ((bh && bh->b_count != 1) || tmp != *p) {
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retry = 1;
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retry = 1;
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brelse(bh);
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brelse(bh);
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continue;
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continue;
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}
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}
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*p = 0;
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*p = 0;
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inode->i_dirt = 1;
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inode->i_dirt = 1;
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brelse(bh);
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brelse(bh);
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ext_free_block(inode->i_sb,tmp);
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ext_free_block(inode->i_sb,tmp);
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}
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}
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return retry;
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return retry;
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}
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}
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static int trunc_indirect(struct inode * inode, int offset, unsigned long * p)
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static int trunc_indirect(struct inode * inode, int offset, unsigned long * p)
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{
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{
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int i, tmp;
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int i, tmp;
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struct buffer_head * bh;
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struct buffer_head * bh;
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struct buffer_head * ind_bh;
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struct buffer_head * ind_bh;
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unsigned long * ind;
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unsigned long * ind;
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int retry = 0;
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int retry = 0;
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#define INDIRECT_BLOCK (DIRECT_BLOCK-offset)
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#define INDIRECT_BLOCK (DIRECT_BLOCK-offset)
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tmp = *p;
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tmp = *p;
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if (!tmp)
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if (!tmp)
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return 0;
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return 0;
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ind_bh = bread(inode->i_dev, tmp, BLOCK_SIZE);
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ind_bh = bread(inode->i_dev, tmp, BLOCK_SIZE);
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if (tmp != *p) {
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if (tmp != *p) {
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brelse(ind_bh);
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brelse(ind_bh);
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return 1;
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return 1;
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}
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}
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if (!ind_bh) {
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if (!ind_bh) {
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*p = 0;
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*p = 0;
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return 0;
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return 0;
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}
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}
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repeat:
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repeat:
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for (i = INDIRECT_BLOCK ; i < 256 ; i++) {
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for (i = INDIRECT_BLOCK ; i < 256 ; i++) {
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if (i < 0)
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if (i < 0)
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i = 0;
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i = 0;
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if (i < INDIRECT_BLOCK)
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if (i < INDIRECT_BLOCK)
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goto repeat;
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goto repeat;
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ind = i+(unsigned long *) ind_bh->b_data;
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ind = i+(unsigned long *) ind_bh->b_data;
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tmp = *ind;
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tmp = *ind;
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if (!tmp)
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if (!tmp)
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continue;
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continue;
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bh = getblk(inode->i_dev,tmp,BLOCK_SIZE);
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bh = getblk(inode->i_dev,tmp,BLOCK_SIZE);
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if (i < INDIRECT_BLOCK) {
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if (i < INDIRECT_BLOCK) {
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brelse(bh);
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brelse(bh);
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goto repeat;
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goto repeat;
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}
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}
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if ((bh && bh->b_count != 1) || tmp != *ind) {
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if ((bh && bh->b_count != 1) || tmp != *ind) {
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retry = 1;
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retry = 1;
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brelse(bh);
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brelse(bh);
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continue;
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continue;
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}
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}
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*ind = 0;
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*ind = 0;
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mark_buffer_dirty(ind_bh, 1);
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mark_buffer_dirty(ind_bh, 1);
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brelse(bh);
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brelse(bh);
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ext_free_block(inode->i_sb,tmp);
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ext_free_block(inode->i_sb,tmp);
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}
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}
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ind = (unsigned long *) ind_bh->b_data;
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ind = (unsigned long *) ind_bh->b_data;
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for (i = 0; i < 256; i++)
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for (i = 0; i < 256; i++)
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if (*(ind++))
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if (*(ind++))
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break;
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break;
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if (i >= 256)
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if (i >= 256)
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if (ind_bh->b_count != 1)
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if (ind_bh->b_count != 1)
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retry = 1;
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retry = 1;
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else {
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else {
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tmp = *p;
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tmp = *p;
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*p = 0;
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*p = 0;
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inode->i_dirt = 1;
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inode->i_dirt = 1;
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ext_free_block(inode->i_sb,tmp);
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ext_free_block(inode->i_sb,tmp);
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}
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}
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brelse(ind_bh);
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brelse(ind_bh);
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return retry;
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return retry;
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}
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}
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static int trunc_dindirect(struct inode * inode, int offset, unsigned long * p)
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static int trunc_dindirect(struct inode * inode, int offset, unsigned long * p)
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{
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{
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int i,tmp;
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int i,tmp;
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struct buffer_head * dind_bh;
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struct buffer_head * dind_bh;
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unsigned long * dind;
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unsigned long * dind;
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int retry = 0;
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int retry = 0;
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#define DINDIRECT_BLOCK ((DIRECT_BLOCK-offset)>>8)
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#define DINDIRECT_BLOCK ((DIRECT_BLOCK-offset)>>8)
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tmp = *p;
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tmp = *p;
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if (!tmp)
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if (!tmp)
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return 0;
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return 0;
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dind_bh = bread(inode->i_dev, tmp, BLOCK_SIZE);
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dind_bh = bread(inode->i_dev, tmp, BLOCK_SIZE);
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if (tmp != *p) {
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if (tmp != *p) {
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brelse(dind_bh);
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brelse(dind_bh);
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return 1;
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return 1;
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}
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}
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if (!dind_bh) {
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if (!dind_bh) {
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*p = 0;
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*p = 0;
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return 0;
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return 0;
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}
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}
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repeat:
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repeat:
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for (i = DINDIRECT_BLOCK ; i < 256 ; i ++) {
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for (i = DINDIRECT_BLOCK ; i < 256 ; i ++) {
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if (i < 0)
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if (i < 0)
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i = 0;
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i = 0;
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if (i < DINDIRECT_BLOCK)
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if (i < DINDIRECT_BLOCK)
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goto repeat;
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goto repeat;
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dind = i+(unsigned long *) dind_bh->b_data;
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dind = i+(unsigned long *) dind_bh->b_data;
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tmp = *dind;
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tmp = *dind;
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if (!tmp)
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if (!tmp)
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continue;
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continue;
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retry |= trunc_indirect(inode,offset+(i<<8),dind);
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retry |= trunc_indirect(inode,offset+(i<<8),dind);
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mark_buffer_dirty(dind_bh, 1);
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mark_buffer_dirty(dind_bh, 1);
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}
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}
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dind = (unsigned long *) dind_bh->b_data;
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dind = (unsigned long *) dind_bh->b_data;
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for (i = 0; i < 256; i++)
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for (i = 0; i < 256; i++)
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if (*(dind++))
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if (*(dind++))
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break;
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break;
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if (i >= 256)
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if (i >= 256)
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if (dind_bh->b_count != 1)
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if (dind_bh->b_count != 1)
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retry = 1;
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retry = 1;
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else {
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else {
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tmp = *p;
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tmp = *p;
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*p = 0;
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*p = 0;
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inode->i_dirt = 1;
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inode->i_dirt = 1;
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ext_free_block(inode->i_sb,tmp);
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ext_free_block(inode->i_sb,tmp);
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}
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}
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brelse(dind_bh);
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brelse(dind_bh);
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return retry;
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return retry;
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}
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}
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static int trunc_tindirect(struct inode * inode)
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static int trunc_tindirect(struct inode * inode)
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{
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{
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int i,tmp;
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int i,tmp;
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struct buffer_head * tind_bh;
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struct buffer_head * tind_bh;
|
unsigned long * tind, * p;
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unsigned long * tind, * p;
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int retry = 0;
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int retry = 0;
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#define TINDIRECT_BLOCK ((DIRECT_BLOCK-(256*256+256+9))>>16)
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#define TINDIRECT_BLOCK ((DIRECT_BLOCK-(256*256+256+9))>>16)
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|
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p = inode->u.ext_i.i_data+11;
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p = inode->u.ext_i.i_data+11;
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if (!(tmp = *p))
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if (!(tmp = *p))
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return 0;
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return 0;
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tind_bh = bread(inode->i_dev, tmp, BLOCK_SIZE);
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tind_bh = bread(inode->i_dev, tmp, BLOCK_SIZE);
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if (tmp != *p) {
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if (tmp != *p) {
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brelse(tind_bh);
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brelse(tind_bh);
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return 1;
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return 1;
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}
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}
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if (!tind_bh) {
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if (!tind_bh) {
|
*p = 0;
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*p = 0;
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return 0;
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return 0;
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}
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}
|
repeat:
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repeat:
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for (i = TINDIRECT_BLOCK ; i < 256 ; i ++) {
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for (i = TINDIRECT_BLOCK ; i < 256 ; i ++) {
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if (i < 0)
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if (i < 0)
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i = 0;
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i = 0;
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if (i < TINDIRECT_BLOCK)
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if (i < TINDIRECT_BLOCK)
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goto repeat;
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goto repeat;
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tind = i+(unsigned long *) tind_bh->b_data;
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tind = i+(unsigned long *) tind_bh->b_data;
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retry |= trunc_dindirect(inode,9+256+256*256+(i<<16),tind);
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retry |= trunc_dindirect(inode,9+256+256*256+(i<<16),tind);
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mark_buffer_dirty(tind_bh, 1);
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mark_buffer_dirty(tind_bh, 1);
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}
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}
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tind = (unsigned long *) tind_bh->b_data;
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tind = (unsigned long *) tind_bh->b_data;
|
for (i = 0; i < 256; i++)
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for (i = 0; i < 256; i++)
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if (*(tind++))
|
if (*(tind++))
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break;
|
break;
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if (i >= 256)
|
if (i >= 256)
|
if (tind_bh->b_count != 1)
|
if (tind_bh->b_count != 1)
|
retry = 1;
|
retry = 1;
|
else {
|
else {
|
tmp = *p;
|
tmp = *p;
|
*p = 0;
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*p = 0;
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inode->i_dirt = 1;
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inode->i_dirt = 1;
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ext_free_block(inode->i_sb,tmp);
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ext_free_block(inode->i_sb,tmp);
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}
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}
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brelse(tind_bh);
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brelse(tind_bh);
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return retry;
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return retry;
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}
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}
|
|
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void ext_truncate(struct inode * inode)
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void ext_truncate(struct inode * inode)
|
{
|
{
|
int retry;
|
int retry;
|
|
|
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
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if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
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S_ISLNK(inode->i_mode)))
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S_ISLNK(inode->i_mode)))
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return;
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return;
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while (1) {
|
while (1) {
|
retry = trunc_direct(inode);
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retry = trunc_direct(inode);
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retry |= trunc_indirect(inode,9,inode->u.ext_i.i_data+9);
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retry |= trunc_indirect(inode,9,inode->u.ext_i.i_data+9);
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retry |= trunc_dindirect(inode,9+256,inode->u.ext_i.i_data+10);
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retry |= trunc_dindirect(inode,9+256,inode->u.ext_i.i_data+10);
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retry |= trunc_tindirect(inode);
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retry |= trunc_tindirect(inode);
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if (!retry)
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if (!retry)
|
break;
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break;
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current->counter = 0;
|
current->counter = 0;
|
schedule();
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schedule();
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}
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}
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inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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inode->i_dirt = 1;
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inode->i_dirt = 1;
|
}
|
}
|
|
|
/*
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/*
|
* Called when a inode is released. Note that this is different
|
* Called when a inode is released. Note that this is different
|
* from ext_open: open gets called at every open, but release
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* from ext_open: open gets called at every open, but release
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* gets called only when /all/ the files are closed.
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* gets called only when /all/ the files are closed.
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*/
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*/
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void ext_release(struct inode * inode, struct file * filp)
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void ext_release(struct inode * inode, struct file * filp)
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{
|
{
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printk("ext_release not implemented\n");
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printk("ext_release not implemented\n");
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}
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}
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|
|
