475 lines
11 KiB
C
475 lines
11 KiB
C
/*
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* linux/fs/ufs/truncate.c
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*
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* Copyright (C) 1998
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* Daniel Pirkl <daniel.pirkl@email.cz>
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* Charles University, Faculty of Mathematics and Physics
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*
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* from
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*
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* linux/fs/ext2/truncate.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/truncate.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* Big-endian to little-endian byte-swapping/bitmaps by
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* David S. Miller (davem@caip.rutgers.edu), 1995
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*/
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/*
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* Real random numbers for secure rm added 94/02/18
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* Idea from Pierre del Perugia <delperug@gla.ecoledoc.ibp.fr>
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*/
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/ufs_fs.h>
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#include <linux/fcntl.h>
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#include <linux/time.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/smp_lock.h>
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#include <linux/buffer_head.h>
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#include <linux/blkdev.h>
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#include <linux/sched.h>
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#include "swab.h"
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#include "util.h"
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#undef UFS_TRUNCATE_DEBUG
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#ifdef UFS_TRUNCATE_DEBUG
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#define UFSD(x) printk("(%s, %d), %s: ", __FILE__, __LINE__, __FUNCTION__); printk x;
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#else
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#define UFSD(x)
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#endif
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/*
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* Secure deletion currently doesn't work. It interacts very badly
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* with buffers shared with memory mappings, and for that reason
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* can't be done in the truncate() routines. It should instead be
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* done separately in "release()" before calling the truncate routines
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* that will release the actual file blocks.
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*
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* Linus
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*/
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#define DIRECT_BLOCK ((inode->i_size + uspi->s_bsize - 1) >> uspi->s_bshift)
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#define DIRECT_FRAGMENT ((inode->i_size + uspi->s_fsize - 1) >> uspi->s_fshift)
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#define DATA_BUFFER_USED(bh) \
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(atomic_read(&bh->b_count)>1 || buffer_locked(bh))
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static int ufs_trunc_direct (struct inode * inode)
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{
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struct ufs_inode_info *ufsi = UFS_I(inode);
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struct super_block * sb;
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struct ufs_sb_private_info * uspi;
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struct buffer_head * bh;
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__fs32 * p;
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unsigned frag1, frag2, frag3, frag4, block1, block2;
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unsigned frag_to_free, free_count;
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unsigned i, j, tmp;
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int retry;
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UFSD(("ENTER\n"))
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sb = inode->i_sb;
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uspi = UFS_SB(sb)->s_uspi;
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frag_to_free = 0;
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free_count = 0;
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retry = 0;
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frag1 = DIRECT_FRAGMENT;
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frag4 = min_t(u32, UFS_NDIR_FRAGMENT, ufsi->i_lastfrag);
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frag2 = ((frag1 & uspi->s_fpbmask) ? ((frag1 | uspi->s_fpbmask) + 1) : frag1);
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frag3 = frag4 & ~uspi->s_fpbmask;
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block1 = block2 = 0;
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if (frag2 > frag3) {
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frag2 = frag4;
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frag3 = frag4 = 0;
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}
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else if (frag2 < frag3) {
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block1 = ufs_fragstoblks (frag2);
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block2 = ufs_fragstoblks (frag3);
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}
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UFSD(("frag1 %u, frag2 %u, block1 %u, block2 %u, frag3 %u, frag4 %u\n", frag1, frag2, block1, block2, frag3, frag4))
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if (frag1 >= frag2)
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goto next1;
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/*
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* Free first free fragments
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*/
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p = ufsi->i_u1.i_data + ufs_fragstoblks (frag1);
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tmp = fs32_to_cpu(sb, *p);
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if (!tmp )
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ufs_panic (sb, "ufs_trunc_direct", "internal error");
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frag1 = ufs_fragnum (frag1);
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frag2 = ufs_fragnum (frag2);
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for (j = frag1; j < frag2; j++) {
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bh = sb_find_get_block (sb, tmp + j);
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if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *p)) {
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retry = 1;
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brelse (bh);
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goto next1;
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}
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bforget (bh);
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}
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inode->i_blocks -= (frag2-frag1) << uspi->s_nspfshift;
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mark_inode_dirty(inode);
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ufs_free_fragments (inode, tmp + frag1, frag2 - frag1);
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frag_to_free = tmp + frag1;
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next1:
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/*
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* Free whole blocks
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*/
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for (i = block1 ; i < block2; i++) {
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p = ufsi->i_u1.i_data + i;
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tmp = fs32_to_cpu(sb, *p);
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if (!tmp)
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continue;
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for (j = 0; j < uspi->s_fpb; j++) {
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bh = sb_find_get_block(sb, tmp + j);
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if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *p)) {
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retry = 1;
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brelse (bh);
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goto next2;
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}
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bforget (bh);
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}
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*p = 0;
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inode->i_blocks -= uspi->s_nspb;
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mark_inode_dirty(inode);
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if (free_count == 0) {
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frag_to_free = tmp;
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free_count = uspi->s_fpb;
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} else if (free_count > 0 && frag_to_free == tmp - free_count)
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free_count += uspi->s_fpb;
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else {
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ufs_free_blocks (inode, frag_to_free, free_count);
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frag_to_free = tmp;
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free_count = uspi->s_fpb;
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}
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next2:;
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}
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if (free_count > 0)
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ufs_free_blocks (inode, frag_to_free, free_count);
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if (frag3 >= frag4)
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goto next3;
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/*
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* Free last free fragments
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*/
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p = ufsi->i_u1.i_data + ufs_fragstoblks (frag3);
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tmp = fs32_to_cpu(sb, *p);
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if (!tmp )
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ufs_panic(sb, "ufs_truncate_direct", "internal error");
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frag4 = ufs_fragnum (frag4);
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for (j = 0; j < frag4; j++) {
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bh = sb_find_get_block (sb, tmp + j);
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if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *p)) {
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retry = 1;
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brelse (bh);
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goto next1;
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}
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bforget (bh);
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}
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*p = 0;
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inode->i_blocks -= frag4 << uspi->s_nspfshift;
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mark_inode_dirty(inode);
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ufs_free_fragments (inode, tmp, frag4);
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next3:
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UFSD(("EXIT\n"))
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return retry;
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}
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static int ufs_trunc_indirect (struct inode * inode, unsigned offset, __fs32 *p)
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{
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struct super_block * sb;
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struct ufs_sb_private_info * uspi;
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struct ufs_buffer_head * ind_ubh;
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struct buffer_head * bh;
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__fs32 * ind;
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unsigned indirect_block, i, j, tmp;
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unsigned frag_to_free, free_count;
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int retry;
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UFSD(("ENTER\n"))
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sb = inode->i_sb;
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uspi = UFS_SB(sb)->s_uspi;
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frag_to_free = 0;
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free_count = 0;
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retry = 0;
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tmp = fs32_to_cpu(sb, *p);
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if (!tmp)
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return 0;
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ind_ubh = ubh_bread(sb, tmp, uspi->s_bsize);
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if (tmp != fs32_to_cpu(sb, *p)) {
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ubh_brelse (ind_ubh);
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return 1;
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}
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if (!ind_ubh) {
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*p = 0;
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return 0;
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}
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indirect_block = (DIRECT_BLOCK > offset) ? (DIRECT_BLOCK - offset) : 0;
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for (i = indirect_block; i < uspi->s_apb; i++) {
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ind = ubh_get_addr32 (ind_ubh, i);
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tmp = fs32_to_cpu(sb, *ind);
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if (!tmp)
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continue;
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for (j = 0; j < uspi->s_fpb; j++) {
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bh = sb_find_get_block(sb, tmp + j);
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if ((bh && DATA_BUFFER_USED(bh)) || tmp != fs32_to_cpu(sb, *ind)) {
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retry = 1;
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brelse (bh);
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goto next;
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}
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bforget (bh);
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}
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*ind = 0;
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ubh_mark_buffer_dirty(ind_ubh);
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if (free_count == 0) {
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frag_to_free = tmp;
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free_count = uspi->s_fpb;
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} else if (free_count > 0 && frag_to_free == tmp - free_count)
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free_count += uspi->s_fpb;
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else {
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ufs_free_blocks (inode, frag_to_free, free_count);
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frag_to_free = tmp;
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free_count = uspi->s_fpb;
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}
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inode->i_blocks -= uspi->s_nspb;
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mark_inode_dirty(inode);
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next:;
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}
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if (free_count > 0) {
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ufs_free_blocks (inode, frag_to_free, free_count);
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}
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for (i = 0; i < uspi->s_apb; i++)
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if (*ubh_get_addr32(ind_ubh,i))
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break;
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if (i >= uspi->s_apb) {
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if (ubh_max_bcount(ind_ubh) != 1) {
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retry = 1;
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}
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else {
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tmp = fs32_to_cpu(sb, *p);
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*p = 0;
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inode->i_blocks -= uspi->s_nspb;
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mark_inode_dirty(inode);
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ufs_free_blocks (inode, tmp, uspi->s_fpb);
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ubh_bforget(ind_ubh);
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ind_ubh = NULL;
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}
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}
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if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh)) {
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ubh_ll_rw_block (SWRITE, 1, &ind_ubh);
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ubh_wait_on_buffer (ind_ubh);
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}
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ubh_brelse (ind_ubh);
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UFSD(("EXIT\n"))
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return retry;
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}
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static int ufs_trunc_dindirect (struct inode *inode, unsigned offset, __fs32 *p)
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{
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struct super_block * sb;
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struct ufs_sb_private_info * uspi;
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struct ufs_buffer_head * dind_bh;
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unsigned i, tmp, dindirect_block;
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__fs32 * dind;
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int retry = 0;
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UFSD(("ENTER\n"))
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sb = inode->i_sb;
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uspi = UFS_SB(sb)->s_uspi;
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dindirect_block = (DIRECT_BLOCK > offset)
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? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
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retry = 0;
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tmp = fs32_to_cpu(sb, *p);
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if (!tmp)
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return 0;
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dind_bh = ubh_bread(sb, tmp, uspi->s_bsize);
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if (tmp != fs32_to_cpu(sb, *p)) {
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ubh_brelse (dind_bh);
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return 1;
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}
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if (!dind_bh) {
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*p = 0;
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return 0;
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}
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for (i = dindirect_block ; i < uspi->s_apb ; i++) {
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dind = ubh_get_addr32 (dind_bh, i);
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tmp = fs32_to_cpu(sb, *dind);
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if (!tmp)
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continue;
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retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
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ubh_mark_buffer_dirty(dind_bh);
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}
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for (i = 0; i < uspi->s_apb; i++)
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if (*ubh_get_addr32 (dind_bh, i))
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break;
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if (i >= uspi->s_apb) {
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if (ubh_max_bcount(dind_bh) != 1)
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retry = 1;
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else {
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tmp = fs32_to_cpu(sb, *p);
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*p = 0;
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inode->i_blocks -= uspi->s_nspb;
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mark_inode_dirty(inode);
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ufs_free_blocks (inode, tmp, uspi->s_fpb);
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ubh_bforget(dind_bh);
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dind_bh = NULL;
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}
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}
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if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
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ubh_ll_rw_block (SWRITE, 1, &dind_bh);
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ubh_wait_on_buffer (dind_bh);
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}
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ubh_brelse (dind_bh);
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UFSD(("EXIT\n"))
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return retry;
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}
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static int ufs_trunc_tindirect (struct inode * inode)
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{
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struct ufs_inode_info *ufsi = UFS_I(inode);
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struct super_block * sb;
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struct ufs_sb_private_info * uspi;
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struct ufs_buffer_head * tind_bh;
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unsigned tindirect_block, tmp, i;
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__fs32 * tind, * p;
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int retry;
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UFSD(("ENTER\n"))
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sb = inode->i_sb;
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uspi = UFS_SB(sb)->s_uspi;
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retry = 0;
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tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
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? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;
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p = ufsi->i_u1.i_data + UFS_TIND_BLOCK;
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if (!(tmp = fs32_to_cpu(sb, *p)))
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return 0;
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tind_bh = ubh_bread (sb, tmp, uspi->s_bsize);
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if (tmp != fs32_to_cpu(sb, *p)) {
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ubh_brelse (tind_bh);
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return 1;
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}
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if (!tind_bh) {
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*p = 0;
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return 0;
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}
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for (i = tindirect_block ; i < uspi->s_apb ; i++) {
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tind = ubh_get_addr32 (tind_bh, i);
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retry |= ufs_trunc_dindirect(inode, UFS_NDADDR +
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uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
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ubh_mark_buffer_dirty(tind_bh);
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}
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for (i = 0; i < uspi->s_apb; i++)
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if (*ubh_get_addr32 (tind_bh, i))
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break;
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if (i >= uspi->s_apb) {
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if (ubh_max_bcount(tind_bh) != 1)
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retry = 1;
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else {
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tmp = fs32_to_cpu(sb, *p);
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*p = 0;
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inode->i_blocks -= uspi->s_nspb;
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mark_inode_dirty(inode);
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ufs_free_blocks (inode, tmp, uspi->s_fpb);
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ubh_bforget(tind_bh);
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tind_bh = NULL;
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}
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}
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if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
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ubh_ll_rw_block (SWRITE, 1, &tind_bh);
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ubh_wait_on_buffer (tind_bh);
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}
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ubh_brelse (tind_bh);
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UFSD(("EXIT\n"))
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return retry;
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}
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void ufs_truncate (struct inode * inode)
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{
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struct ufs_inode_info *ufsi = UFS_I(inode);
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struct super_block * sb;
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struct ufs_sb_private_info * uspi;
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struct buffer_head * bh;
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unsigned offset;
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int err, retry;
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UFSD(("ENTER\n"))
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sb = inode->i_sb;
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uspi = UFS_SB(sb)->s_uspi;
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if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))
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return;
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if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
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return;
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lock_kernel();
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while (1) {
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retry = ufs_trunc_direct(inode);
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retry |= ufs_trunc_indirect (inode, UFS_IND_BLOCK,
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(__fs32 *) &ufsi->i_u1.i_data[UFS_IND_BLOCK]);
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retry |= ufs_trunc_dindirect (inode, UFS_IND_BLOCK + uspi->s_apb,
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(__fs32 *) &ufsi->i_u1.i_data[UFS_DIND_BLOCK]);
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retry |= ufs_trunc_tindirect (inode);
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if (!retry)
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break;
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if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
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ufs_sync_inode (inode);
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blk_run_address_space(inode->i_mapping);
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yield();
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}
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offset = inode->i_size & uspi->s_fshift;
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if (offset) {
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bh = ufs_bread (inode, inode->i_size >> uspi->s_fshift, 0, &err);
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if (bh) {
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memset (bh->b_data + offset, 0, uspi->s_fsize - offset);
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mark_buffer_dirty (bh);
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brelse (bh);
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}
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}
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inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
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ufsi->i_lastfrag = DIRECT_FRAGMENT;
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unlock_kernel();
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mark_inode_dirty(inode);
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UFSD(("EXIT\n"))
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}
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