kernel-ark/fs/ufs/truncate.c
Evgeniy Dushistov ecdc639487 [PATCH] ufs: truncate correction
1) When we allocated last fragment in ufs_truncate, we read page, check
   if block mapped to address, and if not trying to allocate it.  This is
   wrong behaviour, fragment may be NOT allocated, but mapped, this
   happened because of "block map" function not checked allocated fragment
   or not, it just take address of the first fragment in the block, add
   offset of fragment and return result, this is correct behaviour in
   almost all situation except call from ufs_truncate.

2) Almost all implementation of UFS, which I can investigate have such
   "defect": if you have full disk, and try truncate file, for example 3GB
   to 2MB, and have hole in this region, truncate return -ENOSPC.  I tried
   evade from this problem, but "block allocation" algorithm is tied to
   right value of i_lastfrag, and fix of this corner case may slow down of
   ordinaries scenarios, so this patch makes behavior of "truncate"
   operations similar to what other UFS implementations do.

Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-08-27 11:01:31 -07:00

508 lines
12 KiB
C

/*
* linux/fs/ufs/truncate.c
*
* Copyright (C) 1998
* Daniel Pirkl <daniel.pirkl@email.cz>
* Charles University, Faculty of Mathematics and Physics
*
* from
*
* linux/fs/ext2/truncate.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/truncate.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* Big-endian to little-endian byte-swapping/bitmaps by
* David S. Miller (davem@caip.rutgers.edu), 1995
*/
/*
* Real random numbers for secure rm added 94/02/18
* Idea from Pierre del Perugia <delperug@gla.ecoledoc.ibp.fr>
*/
/*
* Modified to avoid infinite loop on 2006 by
* Evgeniy Dushistov <dushistov@mail.ru>
*/
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/ufs_fs.h>
#include <linux/fcntl.h>
#include <linux/time.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/blkdev.h>
#include <linux/sched.h>
#include "swab.h"
#include "util.h"
/*
* Secure deletion currently doesn't work. It interacts very badly
* with buffers shared with memory mappings, and for that reason
* can't be done in the truncate() routines. It should instead be
* done separately in "release()" before calling the truncate routines
* that will release the actual file blocks.
*
* Linus
*/
#define DIRECT_BLOCK ((inode->i_size + uspi->s_bsize - 1) >> uspi->s_bshift)
#define DIRECT_FRAGMENT ((inode->i_size + uspi->s_fsize - 1) >> uspi->s_fshift)
static int ufs_trunc_direct (struct inode * inode)
{
struct ufs_inode_info *ufsi = UFS_I(inode);
struct super_block * sb;
struct ufs_sb_private_info * uspi;
__fs32 * p;
unsigned frag1, frag2, frag3, frag4, block1, block2;
unsigned frag_to_free, free_count;
unsigned i, tmp;
int retry;
UFSD("ENTER\n");
sb = inode->i_sb;
uspi = UFS_SB(sb)->s_uspi;
frag_to_free = 0;
free_count = 0;
retry = 0;
frag1 = DIRECT_FRAGMENT;
frag4 = min_t(u32, UFS_NDIR_FRAGMENT, ufsi->i_lastfrag);
frag2 = ((frag1 & uspi->s_fpbmask) ? ((frag1 | uspi->s_fpbmask) + 1) : frag1);
frag3 = frag4 & ~uspi->s_fpbmask;
block1 = block2 = 0;
if (frag2 > frag3) {
frag2 = frag4;
frag3 = frag4 = 0;
}
else if (frag2 < frag3) {
block1 = ufs_fragstoblks (frag2);
block2 = ufs_fragstoblks (frag3);
}
UFSD("frag1 %u, frag2 %u, block1 %u, block2 %u, frag3 %u, frag4 %u\n", frag1, frag2, block1, block2, frag3, frag4);
if (frag1 >= frag2)
goto next1;
/*
* Free first free fragments
*/
p = ufsi->i_u1.i_data + ufs_fragstoblks (frag1);
tmp = fs32_to_cpu(sb, *p);
if (!tmp )
ufs_panic (sb, "ufs_trunc_direct", "internal error");
frag1 = ufs_fragnum (frag1);
frag2 = ufs_fragnum (frag2);
ufs_free_fragments (inode, tmp + frag1, frag2 - frag1);
mark_inode_dirty(inode);
frag_to_free = tmp + frag1;
next1:
/*
* Free whole blocks
*/
for (i = block1 ; i < block2; i++) {
p = ufsi->i_u1.i_data + i;
tmp = fs32_to_cpu(sb, *p);
if (!tmp)
continue;
*p = 0;
if (free_count == 0) {
frag_to_free = tmp;
free_count = uspi->s_fpb;
} else if (free_count > 0 && frag_to_free == tmp - free_count)
free_count += uspi->s_fpb;
else {
ufs_free_blocks (inode, frag_to_free, free_count);
frag_to_free = tmp;
free_count = uspi->s_fpb;
}
mark_inode_dirty(inode);
}
if (free_count > 0)
ufs_free_blocks (inode, frag_to_free, free_count);
if (frag3 >= frag4)
goto next3;
/*
* Free last free fragments
*/
p = ufsi->i_u1.i_data + ufs_fragstoblks (frag3);
tmp = fs32_to_cpu(sb, *p);
if (!tmp )
ufs_panic(sb, "ufs_truncate_direct", "internal error");
frag4 = ufs_fragnum (frag4);
*p = 0;
ufs_free_fragments (inode, tmp, frag4);
mark_inode_dirty(inode);
next3:
UFSD("EXIT\n");
return retry;
}
static int ufs_trunc_indirect (struct inode * inode, unsigned offset, __fs32 *p)
{
struct super_block * sb;
struct ufs_sb_private_info * uspi;
struct ufs_buffer_head * ind_ubh;
__fs32 * ind;
unsigned indirect_block, i, tmp;
unsigned frag_to_free, free_count;
int retry;
UFSD("ENTER\n");
sb = inode->i_sb;
uspi = UFS_SB(sb)->s_uspi;
frag_to_free = 0;
free_count = 0;
retry = 0;
tmp = fs32_to_cpu(sb, *p);
if (!tmp)
return 0;
ind_ubh = ubh_bread(sb, tmp, uspi->s_bsize);
if (tmp != fs32_to_cpu(sb, *p)) {
ubh_brelse (ind_ubh);
return 1;
}
if (!ind_ubh) {
*p = 0;
return 0;
}
indirect_block = (DIRECT_BLOCK > offset) ? (DIRECT_BLOCK - offset) : 0;
for (i = indirect_block; i < uspi->s_apb; i++) {
ind = ubh_get_addr32 (ind_ubh, i);
tmp = fs32_to_cpu(sb, *ind);
if (!tmp)
continue;
*ind = 0;
ubh_mark_buffer_dirty(ind_ubh);
if (free_count == 0) {
frag_to_free = tmp;
free_count = uspi->s_fpb;
} else if (free_count > 0 && frag_to_free == tmp - free_count)
free_count += uspi->s_fpb;
else {
ufs_free_blocks (inode, frag_to_free, free_count);
frag_to_free = tmp;
free_count = uspi->s_fpb;
}
mark_inode_dirty(inode);
}
if (free_count > 0) {
ufs_free_blocks (inode, frag_to_free, free_count);
}
for (i = 0; i < uspi->s_apb; i++)
if (*ubh_get_addr32(ind_ubh,i))
break;
if (i >= uspi->s_apb) {
tmp = fs32_to_cpu(sb, *p);
*p = 0;
ufs_free_blocks (inode, tmp, uspi->s_fpb);
mark_inode_dirty(inode);
ubh_bforget(ind_ubh);
ind_ubh = NULL;
}
if (IS_SYNC(inode) && ind_ubh && ubh_buffer_dirty(ind_ubh)) {
ubh_ll_rw_block(SWRITE, ind_ubh);
ubh_wait_on_buffer (ind_ubh);
}
ubh_brelse (ind_ubh);
UFSD("EXIT\n");
return retry;
}
static int ufs_trunc_dindirect (struct inode *inode, unsigned offset, __fs32 *p)
{
struct super_block * sb;
struct ufs_sb_private_info * uspi;
struct ufs_buffer_head * dind_bh;
unsigned i, tmp, dindirect_block;
__fs32 * dind;
int retry = 0;
UFSD("ENTER\n");
sb = inode->i_sb;
uspi = UFS_SB(sb)->s_uspi;
dindirect_block = (DIRECT_BLOCK > offset)
? ((DIRECT_BLOCK - offset) >> uspi->s_apbshift) : 0;
retry = 0;
tmp = fs32_to_cpu(sb, *p);
if (!tmp)
return 0;
dind_bh = ubh_bread(sb, tmp, uspi->s_bsize);
if (tmp != fs32_to_cpu(sb, *p)) {
ubh_brelse (dind_bh);
return 1;
}
if (!dind_bh) {
*p = 0;
return 0;
}
for (i = dindirect_block ; i < uspi->s_apb ; i++) {
dind = ubh_get_addr32 (dind_bh, i);
tmp = fs32_to_cpu(sb, *dind);
if (!tmp)
continue;
retry |= ufs_trunc_indirect (inode, offset + (i << uspi->s_apbshift), dind);
ubh_mark_buffer_dirty(dind_bh);
}
for (i = 0; i < uspi->s_apb; i++)
if (*ubh_get_addr32 (dind_bh, i))
break;
if (i >= uspi->s_apb) {
tmp = fs32_to_cpu(sb, *p);
*p = 0;
ufs_free_blocks(inode, tmp, uspi->s_fpb);
mark_inode_dirty(inode);
ubh_bforget(dind_bh);
dind_bh = NULL;
}
if (IS_SYNC(inode) && dind_bh && ubh_buffer_dirty(dind_bh)) {
ubh_ll_rw_block(SWRITE, dind_bh);
ubh_wait_on_buffer (dind_bh);
}
ubh_brelse (dind_bh);
UFSD("EXIT\n");
return retry;
}
static int ufs_trunc_tindirect (struct inode * inode)
{
struct ufs_inode_info *ufsi = UFS_I(inode);
struct super_block * sb;
struct ufs_sb_private_info * uspi;
struct ufs_buffer_head * tind_bh;
unsigned tindirect_block, tmp, i;
__fs32 * tind, * p;
int retry;
UFSD("ENTER\n");
sb = inode->i_sb;
uspi = UFS_SB(sb)->s_uspi;
retry = 0;
tindirect_block = (DIRECT_BLOCK > (UFS_NDADDR + uspi->s_apb + uspi->s_2apb))
? ((DIRECT_BLOCK - UFS_NDADDR - uspi->s_apb - uspi->s_2apb) >> uspi->s_2apbshift) : 0;
p = ufsi->i_u1.i_data + UFS_TIND_BLOCK;
if (!(tmp = fs32_to_cpu(sb, *p)))
return 0;
tind_bh = ubh_bread (sb, tmp, uspi->s_bsize);
if (tmp != fs32_to_cpu(sb, *p)) {
ubh_brelse (tind_bh);
return 1;
}
if (!tind_bh) {
*p = 0;
return 0;
}
for (i = tindirect_block ; i < uspi->s_apb ; i++) {
tind = ubh_get_addr32 (tind_bh, i);
retry |= ufs_trunc_dindirect(inode, UFS_NDADDR +
uspi->s_apb + ((i + 1) << uspi->s_2apbshift), tind);
ubh_mark_buffer_dirty(tind_bh);
}
for (i = 0; i < uspi->s_apb; i++)
if (*ubh_get_addr32 (tind_bh, i))
break;
if (i >= uspi->s_apb) {
tmp = fs32_to_cpu(sb, *p);
*p = 0;
ufs_free_blocks(inode, tmp, uspi->s_fpb);
mark_inode_dirty(inode);
ubh_bforget(tind_bh);
tind_bh = NULL;
}
if (IS_SYNC(inode) && tind_bh && ubh_buffer_dirty(tind_bh)) {
ubh_ll_rw_block(SWRITE, tind_bh);
ubh_wait_on_buffer (tind_bh);
}
ubh_brelse (tind_bh);
UFSD("EXIT\n");
return retry;
}
static int ufs_alloc_lastblock(struct inode *inode)
{
int err = 0;
struct address_space *mapping = inode->i_mapping;
struct ufs_sb_private_info *uspi = UFS_SB(inode->i_sb)->s_uspi;
unsigned lastfrag, i, end;
struct page *lastpage;
struct buffer_head *bh;
lastfrag = (i_size_read(inode) + uspi->s_fsize - 1) >> uspi->s_fshift;
if (!lastfrag)
goto out;
lastfrag--;
lastpage = ufs_get_locked_page(mapping, lastfrag >>
(PAGE_CACHE_SHIFT - inode->i_blkbits));
if (IS_ERR(lastpage)) {
err = -EIO;
goto out;
}
end = lastfrag & ((1 << (PAGE_CACHE_SHIFT - inode->i_blkbits)) - 1);
bh = page_buffers(lastpage);
for (i = 0; i < end; ++i)
bh = bh->b_this_page;
err = ufs_getfrag_block(inode, lastfrag, bh, 1);
if (unlikely(err))
goto out_unlock;
if (buffer_new(bh)) {
clear_buffer_new(bh);
unmap_underlying_metadata(bh->b_bdev,
bh->b_blocknr);
/*
* we do not zeroize fragment, because of
* if it maped to hole, it already contains zeroes
*/
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
set_page_dirty(lastpage);
}
out_unlock:
ufs_put_locked_page(lastpage);
out:
return err;
}
int ufs_truncate(struct inode *inode, loff_t old_i_size)
{
struct ufs_inode_info *ufsi = UFS_I(inode);
struct super_block *sb = inode->i_sb;
struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
int retry, err = 0;
UFSD("ENTER\n");
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
S_ISLNK(inode->i_mode)))
return -EINVAL;
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return -EPERM;
err = ufs_alloc_lastblock(inode);
if (err) {
i_size_write(inode, old_i_size);
goto out;
}
block_truncate_page(inode->i_mapping, inode->i_size, ufs_getfrag_block);
lock_kernel();
while (1) {
retry = ufs_trunc_direct(inode);
retry |= ufs_trunc_indirect (inode, UFS_IND_BLOCK,
(__fs32 *) &ufsi->i_u1.i_data[UFS_IND_BLOCK]);
retry |= ufs_trunc_dindirect (inode, UFS_IND_BLOCK + uspi->s_apb,
(__fs32 *) &ufsi->i_u1.i_data[UFS_DIND_BLOCK]);
retry |= ufs_trunc_tindirect (inode);
if (!retry)
break;
if (IS_SYNC(inode) && (inode->i_state & I_DIRTY))
ufs_sync_inode (inode);
blk_run_address_space(inode->i_mapping);
yield();
}
inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
ufsi->i_lastfrag = DIRECT_FRAGMENT;
unlock_kernel();
mark_inode_dirty(inode);
out:
UFSD("EXIT: err %d\n", err);
return err;
}
/*
* We don't define our `inode->i_op->truncate', and call it here,
* because of:
* - there is no way to know old size
* - there is no way inform user about error, if it happens in `truncate'
*/
static int ufs_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = dentry->d_inode;
unsigned int ia_valid = attr->ia_valid;
int error;
error = inode_change_ok(inode, attr);
if (error)
return error;
if (ia_valid & ATTR_SIZE &&
attr->ia_size != i_size_read(inode)) {
loff_t old_i_size = inode->i_size;
error = vmtruncate(inode, attr->ia_size);
if (error)
return error;
error = ufs_truncate(inode, old_i_size);
if (error)
return error;
}
return inode_setattr(inode, attr);
}
struct inode_operations ufs_file_inode_operations = {
.setattr = ufs_setattr,
};