linux/fs/gfs2/page.c
Steven Whitehouse 18ec7d5c3f [GFS2] Make journaled data files identical to normal files on disk
This is a very large patch, with a few still to be resolved issues
so you might want to check out the previous head of the tree since
this is known to be unstable. Fixes for the various bugs will be
forthcoming shortly.

This patch removes the special data format which has been used
up till now for journaled data files. Directories still retain the
old format so that they will remain on disk compatible with earlier
releases. As a result you can now do the following with journaled
data files:

 1) mmap them
 2) export them over NFS
 3) convert to/from normal files whenever you want to (the zero length
    restriction is gone)

In addition the level at which GFS' locking is done has changed for all
files (since they all now use the page cache) such that the locking is
done at the page cache level rather than the level of the fs operations.
This should mean that things like loopback mounts and other things which
touch the page cache directly should now work.

Current known issues:

 1. There is a lock mode inversion problem related to the resource
    group hold function which needs to be resolved.
 2. Any significant amount of I/O causes an oops with an offset of hex 320
    (NULL pointer dereference) which appears to be related to a journaled data
    buffer appearing on a list where it shouldn't be.
 3. Direct I/O writes are disabled for the time being (will reappear later)
 4. There is probably a deadlock between the page lock and GFS' locks under
    certain combinations of mmap and fs operation I/O.
 5. Issue relating to ref counting on internally used inodes causes a hang
    on umount (discovered before this patch, and not fixed by it)
 6. One part of the directory metadata is different from GFS1 and will need
    to be resolved before next release.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-02-08 11:50:51 +00:00

280 lines
6.2 KiB
C

/*
* 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 <linux/mm.h>
#include <asm/semaphore.h>
#include "gfs2.h"
#include "bmap.h"
#include "inode.h"
#include "page.h"
#include "trans.h"
#include "ops_address.h"
/**
* gfs2_pte_inval - Sync and invalidate all PTEs associated with a glock
* @gl: the glock
*
*/
void gfs2_pte_inval(struct gfs2_glock *gl)
{
struct gfs2_inode *ip;
struct inode *inode;
ip = get_gl2ip(gl);
if (!ip || !S_ISREG(ip->i_di.di_mode))
return;
if (!test_bit(GIF_PAGED, &ip->i_flags))
return;
inode = gfs2_ip2v_lookup(ip);
if (inode) {
unmap_shared_mapping_range(inode->i_mapping, 0, 0);
iput(inode);
if (test_bit(GIF_SW_PAGED, &ip->i_flags))
set_bit(GLF_DIRTY, &gl->gl_flags);
}
clear_bit(GIF_SW_PAGED, &ip->i_flags);
}
/**
* gfs2_page_inval - Invalidate all pages associated with a glock
* @gl: the glock
*
*/
void gfs2_page_inval(struct gfs2_glock *gl)
{
struct gfs2_inode *ip;
struct inode *inode;
ip = get_gl2ip(gl);
if (!ip || !S_ISREG(ip->i_di.di_mode))
return;
inode = gfs2_ip2v_lookup(ip);
if (inode) {
struct address_space *mapping = inode->i_mapping;
truncate_inode_pages(mapping, 0);
gfs2_assert_withdraw(ip->i_sbd, !mapping->nrpages);
iput(inode);
}
clear_bit(GIF_PAGED, &ip->i_flags);
}
/**
* gfs2_page_sync - Sync the data pages (not metadata) associated with a glock
* @gl: the glock
* @flags: DIO_START | DIO_WAIT
*
* Syncs data (not metadata) for a regular file.
* No-op for all other types.
*/
void gfs2_page_sync(struct gfs2_glock *gl, int flags)
{
struct gfs2_inode *ip;
struct inode *inode;
ip = get_gl2ip(gl);
if (!ip || !S_ISREG(ip->i_di.di_mode))
return;
inode = gfs2_ip2v_lookup(ip);
if (inode) {
struct address_space *mapping = inode->i_mapping;
int error = 0;
if (flags & DIO_START)
filemap_fdatawrite(mapping);
if (!error && (flags & DIO_WAIT))
error = filemap_fdatawait(mapping);
/* Put back any errors cleared by filemap_fdatawait()
so they can be caught by someone who can pass them
up to user space. */
if (error == -ENOSPC)
set_bit(AS_ENOSPC, &mapping->flags);
else if (error)
set_bit(AS_EIO, &mapping->flags);
iput(inode);
}
}
/**
* gfs2_unstuffer_page - unstuff a stuffed inode into a block cached by a page
* @ip: the inode
* @dibh: the dinode buffer
* @block: the block number that was allocated
* @private: any locked page held by the caller process
*
* Returns: errno
*/
int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
uint64_t block, void *private)
{
struct gfs2_sbd *sdp = ip->i_sbd;
struct inode *inode = ip->i_vnode;
struct page *page = (struct page *)private;
struct buffer_head *bh;
int release = 0;
if (!page || page->index) {
page = grab_cache_page(inode->i_mapping, 0);
if (!page)
return -ENOMEM;
release = 1;
}
if (!PageUptodate(page)) {
void *kaddr = kmap(page);
memcpy(kaddr,
dibh->b_data + sizeof(struct gfs2_dinode),
ip->i_di.di_size);
memset(kaddr + ip->i_di.di_size,
0,
PAGE_CACHE_SIZE - ip->i_di.di_size);
kunmap(page);
SetPageUptodate(page);
}
if (!page_has_buffers(page))
create_empty_buffers(page, 1 << inode->i_blkbits,
(1 << BH_Uptodate));
bh = page_buffers(page);
if (!buffer_mapped(bh))
map_bh(bh, inode->i_sb, block);
set_buffer_uptodate(bh);
if ((sdp->sd_args.ar_data == GFS2_DATA_ORDERED) || gfs2_is_jdata(ip))
gfs2_trans_add_bh(ip->i_gl, bh, 0);
mark_buffer_dirty(bh);
if (release) {
unlock_page(page);
page_cache_release(page);
}
return 0;
}
/**
* gfs2_block_truncate_page - Deal with zeroing out data for truncate
*
* This is partly borrowed from ext3.
*/
int gfs2_block_truncate_page(struct address_space *mapping)
{
struct inode *inode = mapping->host;
struct gfs2_inode *ip = get_v2ip(inode);
struct gfs2_sbd *sdp = ip->i_sbd;
loff_t from = inode->i_size;
unsigned long index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
unsigned blocksize, iblock, length, pos;
struct buffer_head *bh;
struct page *page;
void *kaddr;
int err;
page = grab_cache_page(mapping, index);
if (!page)
return 0;
blocksize = inode->i_sb->s_blocksize;
length = blocksize - (offset & (blocksize - 1));
iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
/* Find the buffer that contains "offset" */
bh = page_buffers(page);
pos = blocksize;
while (offset >= pos) {
bh = bh->b_this_page;
iblock++;
pos += blocksize;
}
err = 0;
if (!buffer_mapped(bh)) {
gfs2_get_block(inode, iblock, bh, 0);
/* unmapped? It's a hole - nothing to do */
if (!buffer_mapped(bh))
goto unlock;
}
/* Ok, it's mapped. Make sure it's up-to-date */
if (PageUptodate(page))
set_buffer_uptodate(bh);
if (!buffer_uptodate(bh)) {
err = -EIO;
ll_rw_block(READ, 1, &bh);
wait_on_buffer(bh);
/* Uhhuh. Read error. Complain and punt. */
if (!buffer_uptodate(bh))
goto unlock;
}
if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip))
gfs2_trans_add_bh(ip->i_gl, bh, 0);
kaddr = kmap_atomic(page, KM_USER0);
memset(kaddr + offset, 0, length);
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
unlock:
unlock_page(page);
page_cache_release(page);
return err;
}
void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
unsigned int from, unsigned int to)
{
struct buffer_head *head = page_buffers(page);
unsigned int bsize = head->b_size;
struct buffer_head *bh;
unsigned int start, end;
for (bh = head, start = 0;
bh != head || !start;
bh = bh->b_this_page, start = end) {
end = start + bsize;
if (end <= from || start >= to)
continue;
gfs2_trans_add_bh(ip->i_gl, bh, 0);
}
}