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linux/fs/gfs2/ops_address.c
Steven Whitehouse 64fb4eb7d4 [GFS2] Remove gfs2_databuf in favour of gfs2_bufdata structure 
Removing the gfs2_databuf structure and using gfs2_bufdata instead
is a step towards allowing journaling of data without requiring the
metadata header on each journaled block. The idea is to merge the
code paths for ordered data with that of journaled data, with the
log operations in lops.c tacking account of the different types of
buffers as they are presented to it. Largely the code path for
metadata will be similar too, but obviously through a different set
of log operations.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-01-18 13:14:40 +00:00

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/pagemap.h>
#include <asm/semaphore.h>
#include "gfs2.h"
#include "bmap.h"
#include "glock.h"
#include "inode.h"
#include "jdata.h"
#include "log.h"
#include "meta_io.h"
#include "ops_address.h"
#include "page.h"
#include "quota.h"
#include "trans.h"
/**
* get_block - Fills in a buffer head with details about a block
* @inode: The inode
* @lblock: The block number to look up
* @bh_result: The buffer head to return the result in
* @create: Non-zero if we may add block to the file
*
* Returns: errno
*/
static int get_block(struct inode *inode, sector_t lblock,
struct buffer_head *bh_result, int create)
{
struct gfs2_inode *ip = get_v2ip(inode);
int new = create;
uint64_t dblock;
int error;
error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
if (error)
return error;
if (!dblock)
return 0;
map_bh(bh_result, inode->i_sb, dblock);
if (new)
set_buffer_new(bh_result);
return 0;
}
/**
* get_block_noalloc - Fills in a buffer head with details about a block
* @inode: The inode
* @lblock: The block number to look up
* @bh_result: The buffer head to return the result in
* @create: Non-zero if we may add block to the file
*
* Returns: errno
*/
static int get_block_noalloc(struct inode *inode, sector_t lblock,
struct buffer_head *bh_result, int create)
{
struct gfs2_inode *ip = get_v2ip(inode);
int new = 0;
uint64_t dblock;
int error;
error = gfs2_block_map(ip, lblock, &new, &dblock, NULL);
if (error)
return error;
if (dblock)
map_bh(bh_result, inode->i_sb, dblock);
else if (gfs2_assert_withdraw(ip->i_sbd, !create))
error = -EIO;
return error;
}
static int get_blocks(struct inode *inode, sector_t lblock,
unsigned long max_blocks, struct buffer_head *bh_result,
int create)
{
struct gfs2_inode *ip = get_v2ip(inode);
int new = create;
uint64_t dblock;
uint32_t extlen;
int error;
error = gfs2_block_map(ip, lblock, &new, &dblock, &extlen);
if (error)
return error;
if (!dblock)
return 0;
map_bh(bh_result, inode->i_sb, dblock);
if (new)
set_buffer_new(bh_result);
if (extlen > max_blocks)
extlen = max_blocks;
bh_result->b_size = extlen << inode->i_blkbits;
return 0;
}
static int get_blocks_noalloc(struct inode *inode, sector_t lblock,
unsigned long max_blocks,
struct buffer_head *bh_result, int create)
{
struct gfs2_inode *ip = get_v2ip(inode);
int new = 0;
uint64_t dblock;
uint32_t extlen;
int error;
error = gfs2_block_map(ip, lblock, &new, &dblock, &extlen);
if (error)
return error;
if (dblock) {
map_bh(bh_result, inode->i_sb, dblock);
if (extlen > max_blocks)
extlen = max_blocks;
bh_result->b_size = extlen << inode->i_blkbits;
} else if (gfs2_assert_withdraw(ip->i_sbd, !create))
error = -EIO;
return error;
}
/**
* gfs2_writepage - Write complete page
* @page: Page to write
*
* Returns: errno
*
* Use Linux VFS block_write_full_page() to write one page,
* using GFS2's get_block_noalloc to find which blocks to write.
*/
static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
{
struct gfs2_inode *ip = get_v2ip(page->mapping->host);
struct gfs2_sbd *sdp = ip->i_sbd;
int error;
atomic_inc(&sdp->sd_ops_address);
if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
unlock_page(page);
return -EIO;
}
if (get_transaction) {
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
}
error = block_write_full_page(page, get_block_noalloc, wbc);
gfs2_meta_cache_flush(ip);
return error;
}
/**
* stuffed_readpage - Fill in a Linux page with stuffed file data
* @ip: the inode
* @page: the page
*
* Returns: errno
*/
static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
{
struct buffer_head *dibh;
void *kaddr;
int error;
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
return error;
kaddr = kmap(page);
memcpy((char *)kaddr,
dibh->b_data + sizeof(struct gfs2_dinode),
ip->i_di.di_size);
memset((char *)kaddr + ip->i_di.di_size,
0,
PAGE_CACHE_SIZE - ip->i_di.di_size);
kunmap(page);
brelse(dibh);
SetPageUptodate(page);
return 0;
}
static int zero_readpage(struct page *page)
{
void *kaddr;
kaddr = kmap(page);
memset(kaddr, 0, PAGE_CACHE_SIZE);
kunmap(page);
SetPageUptodate(page);
unlock_page(page);
return 0;
}
/**
* jdata_readpage - readpage that goes through gfs2_jdata_read_mem()
* @ip:
* @page: The page to read
*
* Returns: errno
*/
static int jdata_readpage(struct gfs2_inode *ip, struct page *page)
{
void *kaddr;
int ret;
kaddr = kmap(page);
ret = gfs2_jdata_read_mem(ip, kaddr,
(uint64_t)page->index << PAGE_CACHE_SHIFT,
PAGE_CACHE_SIZE);
if (ret >= 0) {
if (ret < PAGE_CACHE_SIZE)
memset(kaddr + ret, 0, PAGE_CACHE_SIZE - ret);
SetPageUptodate(page);
ret = 0;
}
kunmap(page);
unlock_page(page);
return ret;
}
/**
* gfs2_readpage - readpage with locking
* @file: The file to read a page for
* @page: The page to read
*
* Returns: errno
*/
static int gfs2_readpage(struct file *file, struct page *page)
{
struct gfs2_inode *ip = get_v2ip(page->mapping->host);
struct gfs2_sbd *sdp = ip->i_sbd;
int error;
atomic_inc(&sdp->sd_ops_address);
if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl))) {
unlock_page(page);
return -EOPNOTSUPP;
}
if (!gfs2_is_jdata(ip)) {
if (gfs2_is_stuffed(ip)) {
if (!page->index) {
error = stuffed_readpage(ip, page);
unlock_page(page);
} else
error = zero_readpage(page);
} else
error = block_read_full_page(page, get_block);
} else
error = jdata_readpage(ip, page);
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
error = -EIO;
return error;
}
/**
* gfs2_prepare_write - Prepare to write a page to a file
* @file: The file to write to
* @page: The page which is to be prepared for writing
* @from: From (byte range within page)
* @to: To (byte range within page)
*
* Returns: errno
*/
static int gfs2_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
struct gfs2_inode *ip = get_v2ip(page->mapping->host);
struct gfs2_sbd *sdp = ip->i_sbd;
int error = 0;
atomic_inc(&sdp->sd_ops_address);
if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
return -EOPNOTSUPP;
if (gfs2_is_stuffed(ip)) {
uint64_t file_size;
file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
if (file_size > sdp->sd_sb.sb_bsize -
sizeof(struct gfs2_dinode)) {
error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page,
page);
if (!error)
error = block_prepare_write(page, from, to,
get_block);
} else if (!PageUptodate(page))
error = stuffed_readpage(ip, page);
} else
error = block_prepare_write(page, from, to, get_block);
return error;
}
/**
* gfs2_commit_write - Commit write to a file
* @file: The file to write to
* @page: The page containing the data
* @from: From (byte range within page)
* @to: To (byte range within page)
*
* Returns: errno
*/
static int gfs2_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
struct inode *inode = page->mapping->host;
struct gfs2_inode *ip = get_v2ip(inode);
struct gfs2_sbd *sdp = ip->i_sbd;
int error;
atomic_inc(&sdp->sd_ops_address);
if (gfs2_is_stuffed(ip)) {
struct buffer_head *dibh;
uint64_t file_size;
void *kaddr;
file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto fail;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
kaddr = kmap(page);
memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
(char *)kaddr + from,
to - from);
kunmap(page);
brelse(dibh);
SetPageUptodate(page);
if (inode->i_size < file_size)
i_size_write(inode, file_size);
} else {
if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED)
gfs2_page_add_databufs(sdp, page, from, to);
error = generic_commit_write(file, page, from, to);
if (error)
goto fail;
}
return 0;
fail:
ClearPageUptodate(page);
return error;
}
/**
* gfs2_bmap - Block map function
* @mapping: Address space info
* @lblock: The block to map
*
* Returns: The disk address for the block or 0 on hole or error
*/
static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
{
struct gfs2_inode *ip = get_v2ip(mapping->host);
struct gfs2_holder i_gh;
sector_t dblock = 0;
int error;
atomic_inc(&ip->i_sbd->sd_ops_address);
error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
if (error)
return 0;
if (!gfs2_is_stuffed(ip))
dblock = generic_block_bmap(mapping, lblock, get_block);
gfs2_glock_dq_uninit(&i_gh);
return dblock;
}
static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
struct gfs2_bufdata *bd;
gfs2_log_lock(sdp);
bd = get_v2bd(bh);
if (bd) {
bd->bd_bh = NULL;
set_v2bd(bh, NULL);
gfs2_log_unlock(sdp);
brelse(bh);
} else
gfs2_log_unlock(sdp);
lock_buffer(bh);
clear_buffer_dirty(bh);
bh->b_bdev = NULL;
clear_buffer_mapped(bh);
clear_buffer_req(bh);
clear_buffer_new(bh);
clear_buffer_delay(bh);
unlock_buffer(bh);
}
static int gfs2_invalidatepage(struct page *page, unsigned long offset)
{
struct gfs2_sbd *sdp = get_v2sdp(page->mapping->host->i_sb);
struct buffer_head *head, *bh, *next;
unsigned int curr_off = 0;
int ret = 1;
BUG_ON(!PageLocked(page));
if (!page_has_buffers(page))
return 1;
bh = head = page_buffers(page);
do {
unsigned int next_off = curr_off + bh->b_size;
next = bh->b_this_page;
if (offset <= curr_off)
discard_buffer(sdp, bh);
curr_off = next_off;
bh = next;
} while (bh != head);
if (!offset)
ret = try_to_release_page(page, 0);
return ret;
}
static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
loff_t offset, unsigned long nr_segs)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct gfs2_inode *ip = get_v2ip(inode);
struct gfs2_sbd *sdp = ip->i_sbd;
get_blocks_t *gb = get_blocks;
atomic_inc(&sdp->sd_ops_address);
if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) ||
gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
return -EINVAL;
if (rw == WRITE && !get_transaction)
gb = get_blocks_noalloc;
return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
offset, nr_segs, gb, NULL);
}
struct address_space_operations gfs2_file_aops = {
.writepage = gfs2_writepage,
.readpage = gfs2_readpage,
.sync_page = block_sync_page,
.prepare_write = gfs2_prepare_write,
.commit_write = gfs2_commit_write,
.bmap = gfs2_bmap,
.invalidatepage = gfs2_invalidatepage,
.direct_IO = gfs2_direct_IO,
};
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