linux-hardened/fs/ufs/util.c
Arnd Bergmann 788257d610 ufs: remove the BKL
This introduces a new per-superblock mutex in UFS to replace
the big kernel lock. I have been careful to avoid nested
calls to lock_ufs and to get the lock order right with
respect to other mutexes, in particular lock_super.

I did not make any attempt to prove that the big kernel
lock is not needed in a particular place in the code,
which is very possible.

The mutex has a significant performance impact, so it is only
used on SMP or PREEMPT configurations.

As Nick Piggin noticed, any allocation inside of the lock
may end up deadlocking when we get to ufs_getfrag_block
in the reclaim task, so we now use GFP_NOFS.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Nick Bowler <nbowler@elliptictech.com>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Nick Piggin <npiggin@gmail.com>
2011-03-02 22:27:48 +01:00

283 lines
6.1 KiB
C

/*
* linux/fs/ufs/util.c
*
* Copyright (C) 1998
* Daniel Pirkl <daniel.pirkl@email.cz>
* Charles University, Faculty of Mathematics and Physics
*/
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include "ufs_fs.h"
#include "ufs.h"
#include "swab.h"
#include "util.h"
struct ufs_buffer_head * _ubh_bread_ (struct ufs_sb_private_info * uspi,
struct super_block *sb, u64 fragment, u64 size)
{
struct ufs_buffer_head * ubh;
unsigned i, j ;
u64 count = 0;
if (size & ~uspi->s_fmask)
return NULL;
count = size >> uspi->s_fshift;
if (count > UFS_MAXFRAG)
return NULL;
ubh = (struct ufs_buffer_head *)
kmalloc (sizeof (struct ufs_buffer_head), GFP_NOFS);
if (!ubh)
return NULL;
ubh->fragment = fragment;
ubh->count = count;
for (i = 0; i < count; i++)
if (!(ubh->bh[i] = sb_bread(sb, fragment + i)))
goto failed;
for (; i < UFS_MAXFRAG; i++)
ubh->bh[i] = NULL;
return ubh;
failed:
for (j = 0; j < i; j++)
brelse (ubh->bh[j]);
kfree(ubh);
return NULL;
}
struct ufs_buffer_head * ubh_bread_uspi (struct ufs_sb_private_info * uspi,
struct super_block *sb, u64 fragment, u64 size)
{
unsigned i, j;
u64 count = 0;
if (size & ~uspi->s_fmask)
return NULL;
count = size >> uspi->s_fshift;
if (count <= 0 || count > UFS_MAXFRAG)
return NULL;
USPI_UBH(uspi)->fragment = fragment;
USPI_UBH(uspi)->count = count;
for (i = 0; i < count; i++)
if (!(USPI_UBH(uspi)->bh[i] = sb_bread(sb, fragment + i)))
goto failed;
for (; i < UFS_MAXFRAG; i++)
USPI_UBH(uspi)->bh[i] = NULL;
return USPI_UBH(uspi);
failed:
for (j = 0; j < i; j++)
brelse (USPI_UBH(uspi)->bh[j]);
return NULL;
}
void ubh_brelse (struct ufs_buffer_head * ubh)
{
unsigned i;
if (!ubh)
return;
for (i = 0; i < ubh->count; i++)
brelse (ubh->bh[i]);
kfree (ubh);
}
void ubh_brelse_uspi (struct ufs_sb_private_info * uspi)
{
unsigned i;
if (!USPI_UBH(uspi))
return;
for ( i = 0; i < USPI_UBH(uspi)->count; i++ ) {
brelse (USPI_UBH(uspi)->bh[i]);
USPI_UBH(uspi)->bh[i] = NULL;
}
}
void ubh_mark_buffer_dirty (struct ufs_buffer_head * ubh)
{
unsigned i;
if (!ubh)
return;
for ( i = 0; i < ubh->count; i++ )
mark_buffer_dirty (ubh->bh[i]);
}
void ubh_mark_buffer_uptodate (struct ufs_buffer_head * ubh, int flag)
{
unsigned i;
if (!ubh)
return;
if (flag) {
for ( i = 0; i < ubh->count; i++ )
set_buffer_uptodate (ubh->bh[i]);
} else {
for ( i = 0; i < ubh->count; i++ )
clear_buffer_uptodate (ubh->bh[i]);
}
}
void ubh_sync_block(struct ufs_buffer_head *ubh)
{
if (ubh) {
unsigned i;
for (i = 0; i < ubh->count; i++)
write_dirty_buffer(ubh->bh[i], WRITE);
for (i = 0; i < ubh->count; i++)
wait_on_buffer(ubh->bh[i]);
}
}
void ubh_bforget (struct ufs_buffer_head * ubh)
{
unsigned i;
if (!ubh)
return;
for ( i = 0; i < ubh->count; i++ ) if ( ubh->bh[i] )
bforget (ubh->bh[i]);
}
int ubh_buffer_dirty (struct ufs_buffer_head * ubh)
{
unsigned i;
unsigned result = 0;
if (!ubh)
return 0;
for ( i = 0; i < ubh->count; i++ )
result |= buffer_dirty(ubh->bh[i]);
return result;
}
void _ubh_ubhcpymem_(struct ufs_sb_private_info * uspi,
unsigned char * mem, struct ufs_buffer_head * ubh, unsigned size)
{
unsigned len, bhno;
if (size > (ubh->count << uspi->s_fshift))
size = ubh->count << uspi->s_fshift;
bhno = 0;
while (size) {
len = min_t(unsigned int, size, uspi->s_fsize);
memcpy (mem, ubh->bh[bhno]->b_data, len);
mem += uspi->s_fsize;
size -= len;
bhno++;
}
}
void _ubh_memcpyubh_(struct ufs_sb_private_info * uspi,
struct ufs_buffer_head * ubh, unsigned char * mem, unsigned size)
{
unsigned len, bhno;
if (size > (ubh->count << uspi->s_fshift))
size = ubh->count << uspi->s_fshift;
bhno = 0;
while (size) {
len = min_t(unsigned int, size, uspi->s_fsize);
memcpy (ubh->bh[bhno]->b_data, mem, len);
mem += uspi->s_fsize;
size -= len;
bhno++;
}
}
dev_t
ufs_get_inode_dev(struct super_block *sb, struct ufs_inode_info *ufsi)
{
__u32 fs32;
dev_t dev;
if ((UFS_SB(sb)->s_flags & UFS_ST_MASK) == UFS_ST_SUNx86)
fs32 = fs32_to_cpu(sb, ufsi->i_u1.i_data[1]);
else
fs32 = fs32_to_cpu(sb, ufsi->i_u1.i_data[0]);
switch (UFS_SB(sb)->s_flags & UFS_ST_MASK) {
case UFS_ST_SUNx86:
case UFS_ST_SUN:
if ((fs32 & 0xffff0000) == 0 ||
(fs32 & 0xffff0000) == 0xffff0000)
dev = old_decode_dev(fs32 & 0x7fff);
else
dev = MKDEV(sysv_major(fs32), sysv_minor(fs32));
break;
default:
dev = old_decode_dev(fs32);
break;
}
return dev;
}
void
ufs_set_inode_dev(struct super_block *sb, struct ufs_inode_info *ufsi, dev_t dev)
{
__u32 fs32;
switch (UFS_SB(sb)->s_flags & UFS_ST_MASK) {
case UFS_ST_SUNx86:
case UFS_ST_SUN:
fs32 = sysv_encode_dev(dev);
if ((fs32 & 0xffff8000) == 0) {
fs32 = old_encode_dev(dev);
}
break;
default:
fs32 = old_encode_dev(dev);
break;
}
if ((UFS_SB(sb)->s_flags & UFS_ST_MASK) == UFS_ST_SUNx86)
ufsi->i_u1.i_data[1] = cpu_to_fs32(sb, fs32);
else
ufsi->i_u1.i_data[0] = cpu_to_fs32(sb, fs32);
}
/**
* ufs_get_locked_page() - locate, pin and lock a pagecache page, if not exist
* read it from disk.
* @mapping: the address_space to search
* @index: the page index
*
* Locates the desired pagecache page, if not exist we'll read it,
* locks it, increments its reference
* count and returns its address.
*
*/
struct page *ufs_get_locked_page(struct address_space *mapping,
pgoff_t index)
{
struct page *page;
page = find_lock_page(mapping, index);
if (!page) {
page = read_mapping_page(mapping, index, NULL);
if (IS_ERR(page)) {
printk(KERN_ERR "ufs_change_blocknr: "
"read_mapping_page error: ino %lu, index: %lu\n",
mapping->host->i_ino, index);
goto out;
}
lock_page(page);
if (unlikely(page->mapping == NULL)) {
/* Truncate got there first */
unlock_page(page);
page_cache_release(page);
page = NULL;
goto out;
}
if (!PageUptodate(page) || PageError(page)) {
unlock_page(page);
page_cache_release(page);
printk(KERN_ERR "ufs_change_blocknr: "
"can not read page: ino %lu, index: %lu\n",
mapping->host->i_ino, index);
page = ERR_PTR(-EIO);
}
}
out:
return page;
}