/*
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/*
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* linux/fs/xiafs/truncate.c
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* linux/fs/xiafs/truncate.c
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*
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*
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* Copyright (C) Q. Frank Xia, 1993.
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* Copyright (C) Q. Frank Xia, 1993.
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*
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*
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* Based on Linus' minix/truncate.c
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* Based on Linus' minix/truncate.c
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* Copyright (C) Linus Torvalds, 1991, 1992.
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* Copyright (C) Linus Torvalds, 1991, 1992.
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*
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*
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* This software may be redistributed per Linux Copyright.
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* This software may be redistributed per Linux Copyright.
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*/
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*/
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#include <linux/errno.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/sched.h>
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#include <linux/xia_fs.h>
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#include <linux/xia_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 "xiafs_mac.h"
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#include "xiafs_mac.h"
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/*
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/*
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* Linus' comment:
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* Linus' comment:
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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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#define DT_ZONE ((inode->i_size + XIAFS_ZSIZE(inode->i_sb) - 1) \
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#define DT_ZONE ((inode->i_size + XIAFS_ZSIZE(inode->i_sb) - 1) \
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>> XIAFS_ZSIZE_BITS(inode->i_sb) )
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>> XIAFS_ZSIZE_BITS(inode->i_sb) )
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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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u_long * lp;
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u_long * lp;
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struct buffer_head * bh;
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struct buffer_head * bh;
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int i, tmp;
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int i, tmp;
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int retry = 0;
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int retry = 0;
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repeat:
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repeat:
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for (i = DT_ZONE ; i < 8 ; i++) {
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for (i = DT_ZONE ; i < 8 ; i++) {
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if (i < DT_ZONE)
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if (i < DT_ZONE)
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goto repeat;
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goto repeat;
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lp=i + inode->u.xiafs_i.i_zone;
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lp=i + inode->u.xiafs_i.i_zone;
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if (!(tmp = *lp))
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if (!(tmp = *lp))
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continue;
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continue;
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bh = getblk(inode->i_dev, tmp, XIAFS_ZSIZE(inode->i_sb));
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bh = getblk(inode->i_dev, tmp, XIAFS_ZSIZE(inode->i_sb));
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if (i < DT_ZONE) {
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if (i < DT_ZONE) {
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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 != *lp)
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if ((bh && bh->b_count != 1) || tmp != *lp)
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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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*lp = 0;
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*lp = 0;
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inode->i_dirt = 1;
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inode->i_dirt = 1;
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inode->i_blocks-=2 << XIAFS_ZSHIFT(inode->i_sb);
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inode->i_blocks-=2 << XIAFS_ZSHIFT(inode->i_sb);
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xiafs_free_zone(inode->i_sb, tmp);
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xiafs_free_zone(inode->i_sb, tmp);
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}
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}
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brelse(bh);
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brelse(bh);
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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 addr_off, u_long * lp)
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static int trunc_indirect(struct inode * inode, int addr_off, u_long * lp)
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{
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{
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|
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#define INDT_ZONE (DT_ZONE - addr_off)
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#define INDT_ZONE (DT_ZONE - addr_off)
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struct buffer_head * bh, * ind_bh;
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struct buffer_head * bh, * ind_bh;
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int i, tmp;
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int i, tmp;
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u_long * indp;
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u_long * indp;
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int retry = 0;
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int retry = 0;
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if ( !(tmp=*lp) )
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if ( !(tmp=*lp) )
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return 0;
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return 0;
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ind_bh = bread(inode->i_dev, tmp, XIAFS_ZSIZE(inode->i_sb));
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ind_bh = bread(inode->i_dev, tmp, XIAFS_ZSIZE(inode->i_sb));
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if (tmp != *lp) {
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if (tmp != *lp) {
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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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*lp = 0;
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*lp = 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 = INDT_ZONE<0?0:INDT_ZONE; i < XIAFS_ADDRS_PER_Z(inode->i_sb); i++) {
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for (i = INDT_ZONE<0?0:INDT_ZONE; i < XIAFS_ADDRS_PER_Z(inode->i_sb); i++) {
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if (i < INDT_ZONE)
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if (i < INDT_ZONE)
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goto repeat;
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goto repeat;
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indp = i+(u_long *) ind_bh->b_data;
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indp = i+(u_long *) ind_bh->b_data;
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if (!(tmp=*indp))
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if (!(tmp=*indp))
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continue;
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continue;
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bh = getblk(inode->i_dev, tmp, XIAFS_ZSIZE(inode->i_sb));
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bh = getblk(inode->i_dev, tmp, XIAFS_ZSIZE(inode->i_sb));
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if (i < INDT_ZONE) {
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if (i < INDT_ZONE) {
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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 != *indp)
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if ((bh && bh->b_count != 1) || tmp != *indp)
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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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*indp = 0;
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*indp = 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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inode->i_blocks-= 2 << XIAFS_ZSHIFT(inode->i_sb);
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inode->i_blocks-= 2 << XIAFS_ZSHIFT(inode->i_sb);
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xiafs_free_zone(inode->i_sb, tmp);
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xiafs_free_zone(inode->i_sb, tmp);
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}
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}
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brelse(bh);
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brelse(bh);
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}
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}
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indp = (u_long *) ind_bh->b_data;
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indp = (u_long *) ind_bh->b_data;
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for (i = 0; i < XIAFS_ADDRS_PER_Z(inode->i_sb) && !(*indp++); i++) ;
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for (i = 0; i < XIAFS_ADDRS_PER_Z(inode->i_sb) && !(*indp++); i++) ;
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if (i >= XIAFS_ADDRS_PER_Z(inode->i_sb)) {
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if (i >= XIAFS_ADDRS_PER_Z(inode->i_sb)) {
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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 = *lp;
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tmp = *lp;
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*lp = 0;
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*lp = 0;
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inode->i_blocks-= 2 << XIAFS_ZSHIFT(inode->i_sb);
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inode->i_blocks-= 2 << XIAFS_ZSHIFT(inode->i_sb);
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xiafs_free_zone(inode->i_sb, tmp);
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xiafs_free_zone(inode->i_sb, tmp);
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}
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}
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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)
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static int trunc_dindirect(struct inode * inode)
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{
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{
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#define DINDT_ZONE \
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#define DINDT_ZONE \
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((DT_ZONE-XIAFS_ADDRS_PER_Z(inode->i_sb)-8)>>XIAFS_ADDRS_PER_Z_BITS(inode->i_sb))
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((DT_ZONE-XIAFS_ADDRS_PER_Z(inode->i_sb)-8)>>XIAFS_ADDRS_PER_Z_BITS(inode->i_sb))
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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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u_long * dindp, * lp;
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u_long * dindp, * lp;
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int retry = 0;
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int retry = 0;
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lp = &(inode->u.xiafs_i.i_dind_zone);
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lp = &(inode->u.xiafs_i.i_dind_zone);
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if (!(tmp = *lp))
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if (!(tmp = *lp))
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return 0;
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return 0;
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dind_bh = bread(inode->i_dev, tmp, XIAFS_ZSIZE(inode->i_sb));
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dind_bh = bread(inode->i_dev, tmp, XIAFS_ZSIZE(inode->i_sb));
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if (tmp != *lp) {
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if (tmp != *lp) {
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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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*lp = 0;
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*lp = 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=DINDT_ZONE<0?0:DINDT_ZONE ; i < XIAFS_ADDRS_PER_Z(inode->i_sb) ; i ++) {
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for (i=DINDT_ZONE<0?0:DINDT_ZONE ; i < XIAFS_ADDRS_PER_Z(inode->i_sb) ; i ++) {
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if (i < DINDT_ZONE)
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if (i < DINDT_ZONE)
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goto repeat;
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goto repeat;
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dindp = i+(u_long *) dind_bh->b_data;
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dindp = i+(u_long *) dind_bh->b_data;
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retry |= trunc_indirect(inode,
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retry |= trunc_indirect(inode,
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8+((1+i)<<XIAFS_ADDRS_PER_Z_BITS(inode->i_sb)),
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8+((1+i)<<XIAFS_ADDRS_PER_Z_BITS(inode->i_sb)),
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dindp);
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dindp);
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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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dindp = (u_long *) dind_bh->b_data;
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dindp = (u_long *) dind_bh->b_data;
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for (i = 0; i < XIAFS_ADDRS_PER_Z(inode->i_sb) && !(*dindp++); i++);
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for (i = 0; i < XIAFS_ADDRS_PER_Z(inode->i_sb) && !(*dindp++); i++);
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if (i >= XIAFS_ADDRS_PER_Z(inode->i_sb)) {
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if (i >= XIAFS_ADDRS_PER_Z(inode->i_sb)) {
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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 = *lp;
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tmp = *lp;
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*lp = 0;
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*lp = 0;
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inode->i_dirt = 1;
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inode->i_dirt = 1;
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inode->i_blocks-=2 << XIAFS_ZSHIFT(inode->i_sb);
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inode->i_blocks-=2 << XIAFS_ZSHIFT(inode->i_sb);
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xiafs_free_zone(inode->i_sb, tmp);
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xiafs_free_zone(inode->i_sb, tmp);
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}
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}
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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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void xiafs_truncate(struct inode * inode)
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void xiafs_truncate(struct inode * inode)
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{
|
{
|
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) {
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while (1) {
|
retry = trunc_direct(inode);
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retry = trunc_direct(inode);
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retry |= trunc_indirect(inode, 8, &(inode->u.xiafs_i.i_ind_zone));
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retry |= trunc_indirect(inode, 8, &(inode->u.xiafs_i.i_ind_zone));
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retry |= trunc_dindirect(inode);
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retry |= trunc_dindirect(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;
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current->counter = 0;
|
schedule();
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schedule();
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}
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}
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inode->i_ctime = inode->i_mtime = CURRENT_TIME;
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inode->i_ctime = inode->i_mtime = CURRENT_TIME;
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inode->i_dirt = 1;
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inode->i_dirt = 1;
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}
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}
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