linux/fs/gfs2/ops_address.c

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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,
};