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linux-sg2042/fs/gfs2/aops.c

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2008 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 version 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/pagevec.h>
#include <linux/mpage.h>
#include <linux/fs.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/gfs2_ondisk.h>
#include <linux/backing-dev.h>
#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "inode.h"
#include "log.h"
#include "meta_io.h"
#include "quota.h"
#include "trans.h"
#include "rgrp.h"
#include "super.h"
#include "util.h"
#include "glops.h"
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;
if (gfs2_is_jdata(ip))
set_buffer_uptodate(bh);
gfs2_trans_add_bh(ip->i_gl, bh, 0);
}
}
/**
* gfs2_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 gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
struct buffer_head *bh_result, int create)
{
int error;
error = gfs2_block_map(inode, lblock, bh_result, 0);
if (error)
return error;
if (!buffer_mapped(bh_result))
return -EIO;
return 0;
}
static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
struct buffer_head *bh_result, int create)
{
return gfs2_block_map(inode, lblock, bh_result, 0);
}
/**
* gfs2_writepage_common - Common bits of writepage
* @page: The page to be written
* @wbc: The writeback control
*
* Returns: 1 if writepage is ok, otherwise an error code or zero if no error.
*/
static int gfs2_writepage_common(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
loff_t i_size = i_size_read(inode);
pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
unsigned offset;
if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
goto out;
if (current->journal_info)
goto redirty;
/* Is the page fully outside i_size? (truncate in progress) */
offset = i_size & (PAGE_CACHE_SIZE-1);
if (page->index > end_index || (page->index == end_index && !offset)) {
page->mapping->a_ops->invalidatepage(page, 0);
goto out;
}
return 1;
redirty:
redirty_page_for_writepage(wbc, page);
out:
unlock_page(page);
return 0;
}
/**
* gfs2_writeback_writepage - Write page for writeback mappings
* @page: The page
* @wbc: The writeback control
*
*/
static int gfs2_writeback_writepage(struct page *page,
struct writeback_control *wbc)
{
int ret;
ret = gfs2_writepage_common(page, wbc);
if (ret <= 0)
return ret;
return nobh_writepage(page, gfs2_get_block_noalloc, wbc);
}
/**
* gfs2_ordered_writepage - Write page for ordered data files
* @page: The page to write
* @wbc: The writeback control
*
*/
static int gfs2_ordered_writepage(struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
int ret;
ret = gfs2_writepage_common(page, wbc);
if (ret <= 0)
return ret;
if (!page_has_buffers(page)) {
create_empty_buffers(page, inode->i_sb->s_blocksize,
(1 << BH_Dirty)|(1 << BH_Uptodate));
}
gfs2_page_add_databufs(ip, page, 0, inode->i_sb->s_blocksize-1);
return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
}
/**
* __gfs2_jdata_writepage - The core of jdata writepage
* @page: The page to write
* @wbc: The writeback control
*
* This is shared between writepage and writepages and implements the
* core of the writepage operation. If a transaction is required then
* PageChecked will have been set and the transaction will have
* already been started before this is called.
*/
static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
if (PageChecked(page)) {
ClearPageChecked(page);
if (!page_has_buffers(page)) {
create_empty_buffers(page, inode->i_sb->s_blocksize,
(1 << BH_Dirty)|(1 << BH_Uptodate));
}
gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
}
return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
}
/**
* gfs2_jdata_writepage - Write complete page
* @page: Page to write
*
* Returns: errno
*
*/
static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
struct gfs2_sbd *sdp = GFS2_SB(inode);
int ret;
int done_trans = 0;
if (PageChecked(page)) {
if (wbc->sync_mode != WB_SYNC_ALL)
goto out_ignore;
ret = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
if (ret)
goto out_ignore;
done_trans = 1;
}
ret = gfs2_writepage_common(page, wbc);
if (ret > 0)
ret = __gfs2_jdata_writepage(page, wbc);
if (done_trans)
gfs2_trans_end(sdp);
return ret;
out_ignore:
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
}
/**
* gfs2_writeback_writepages - Write a bunch of dirty pages back to disk
* @mapping: The mapping to write
* @wbc: Write-back control
*
* For the data=writeback case we can already ignore buffer heads
* and write whole extents at once. This is a big reduction in the
* number of I/O requests we send and the bmap calls we make in this case.
*/
static int gfs2_writeback_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
}
/**
* gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
* @mapping: The mapping
* @wbc: The writeback control
* @writepage: The writepage function to call for each page
* @pvec: The vector of pages
* @nr_pages: The number of pages to write
*
* Returns: non-zero if loop should terminate, zero otherwise
*/
static int gfs2_write_jdata_pagevec(struct address_space *mapping,
struct writeback_control *wbc,
struct pagevec *pvec,
int nr_pages, pgoff_t end)
{
struct inode *inode = mapping->host;
struct gfs2_sbd *sdp = GFS2_SB(inode);
loff_t i_size = i_size_read(inode);
pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
unsigned offset = i_size & (PAGE_CACHE_SIZE-1);
unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize);
int i;
int ret;
ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
if (ret < 0)
return ret;
for(i = 0; i < nr_pages; i++) {
struct page *page = pvec->pages[i];
lock_page(page);
if (unlikely(page->mapping != mapping)) {
unlock_page(page);
continue;
}
if (!wbc->range_cyclic && page->index > end) {
ret = 1;
unlock_page(page);
continue;
}
if (wbc->sync_mode != WB_SYNC_NONE)
wait_on_page_writeback(page);
if (PageWriteback(page) ||
!clear_page_dirty_for_io(page)) {
unlock_page(page);
continue;
}
/* Is the page fully outside i_size? (truncate in progress) */
if (page->index > end_index || (page->index == end_index && !offset)) {
page->mapping->a_ops->invalidatepage(page, 0);
unlock_page(page);
continue;
}
ret = __gfs2_jdata_writepage(page, wbc);
if (ret || (--(wbc->nr_to_write) <= 0))
ret = 1;
}
gfs2_trans_end(sdp);
return ret;
}
/**
* gfs2_write_cache_jdata - Like write_cache_pages but different
* @mapping: The mapping to write
* @wbc: The writeback control
* @writepage: The writepage function to call
* @data: The data to pass to writepage
*
* The reason that we use our own function here is that we need to
* start transactions before we grab page locks. This allows us
* to get the ordering right.
*/
static int gfs2_write_cache_jdata(struct address_space *mapping,
struct writeback_control *wbc)
{
int ret = 0;
int done = 0;
struct pagevec pvec;
int nr_pages;
pgoff_t index;
pgoff_t end;
int scanned = 0;
int range_whole = 0;
pagevec_init(&pvec, 0);
if (wbc->range_cyclic) {
index = mapping->writeback_index; /* Start from prev offset */
end = -1;
} else {
index = wbc->range_start >> PAGE_CACHE_SHIFT;
end = wbc->range_end >> PAGE_CACHE_SHIFT;
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
scanned = 1;
}
retry:
while (!done && (index <= end) &&
(nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
PAGECACHE_TAG_DIRTY,
min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
scanned = 1;
ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end);
if (ret)
done = 1;
if (ret > 0)
ret = 0;
pagevec_release(&pvec);
cond_resched();
}
if (!scanned && !done) {
/*
* We hit the last page and there is more work to be done: wrap
* back to the start of the file
*/
scanned = 1;
index = 0;
goto retry;
}
if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
mapping->writeback_index = index;
return ret;
}
/**
* gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
* @mapping: The mapping to write
* @wbc: The writeback control
*
*/
static int gfs2_jdata_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct gfs2_inode *ip = GFS2_I(mapping->host);
struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
int ret;
ret = gfs2_write_cache_jdata(mapping, wbc);
if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
gfs2_log_flush(sdp, ip->i_gl);
ret = gfs2_write_cache_jdata(mapping, wbc);
}
return ret;
}
/**
* 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;
u64 dsize = i_size_read(&ip->i_inode);
void *kaddr;
int error;
/*
* Due to the order of unstuffing files and ->fault(), we can be
* asked for a zero page in the case of a stuffed file being extended,
* so we need to supply one here. It doesn't happen often.
*/
if (unlikely(page->index)) {
zero_user(page, 0, PAGE_CACHE_SIZE);
SetPageUptodate(page);
return 0;
}
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
return error;
kaddr = kmap_atomic(page);
if (dsize > (dibh->b_size - sizeof(struct gfs2_dinode)))
dsize = (dibh->b_size - sizeof(struct gfs2_dinode));
memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
memset(kaddr + dsize, 0, PAGE_CACHE_SIZE - dsize);
kunmap_atomic(kaddr);
flush_dcache_page(page);
brelse(dibh);
SetPageUptodate(page);
return 0;
}
/**
* __gfs2_readpage - readpage
* @file: The file to read a page for
* @page: The page to read
*
* This is the core of gfs2's readpage. Its used by the internal file
* reading code as in that case we already hold the glock. Also its
* called by gfs2_readpage() once the required lock has been granted.
*
*/
static int __gfs2_readpage(void *file, struct page *page)
{
struct gfs2_inode *ip = GFS2_I(page->mapping->host);
struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
int error;
if (gfs2_is_stuffed(ip)) {
error = stuffed_readpage(ip, page);
unlock_page(page);
} else {
error = mpage_readpage(page, gfs2_block_map);
}
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
return -EIO;
return error;
}
/**
* gfs2_readpage - read a page of a file
* @file: The file to read
* @page: The page of the file
*
* This deals with the locking required. We have to unlock and
* relock the page in order to get the locking in the right
* order.
*/
static int gfs2_readpage(struct file *file, struct page *page)
{
struct address_space *mapping = page->mapping;
struct gfs2_inode *ip = GFS2_I(mapping->host);
struct gfs2_holder gh;
int error;
unlock_page(page);
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
error = gfs2_glock_nq(&gh);
if (unlikely(error))
goto out;
error = AOP_TRUNCATED_PAGE;
lock_page(page);
if (page->mapping == mapping && !PageUptodate(page))
error = __gfs2_readpage(file, page);
else
unlock_page(page);
gfs2_glock_dq(&gh);
out:
gfs2_holder_uninit(&gh);
if (error && error != AOP_TRUNCATED_PAGE)
lock_page(page);
return error;
}
/**
* gfs2_internal_read - read an internal file
* @ip: The gfs2 inode
* @ra_state: The readahead state (or NULL for no readahead)
* @buf: The buffer to fill
* @pos: The file position
* @size: The amount to read
*
*/
int gfs2_internal_read(struct gfs2_inode *ip, struct file_ra_state *ra_state,
char *buf, loff_t *pos, unsigned size)
{
struct address_space *mapping = ip->i_inode.i_mapping;
unsigned long index = *pos / PAGE_CACHE_SIZE;
unsigned offset = *pos & (PAGE_CACHE_SIZE - 1);
unsigned copied = 0;
unsigned amt;
struct page *page;
void *p;
do {
amt = size - copied;
if (offset + size > PAGE_CACHE_SIZE)
amt = PAGE_CACHE_SIZE - offset;
page = read_cache_page(mapping, index, __gfs2_readpage, NULL);
if (IS_ERR(page))
return PTR_ERR(page);
p = kmap_atomic(page);
memcpy(buf + copied, p + offset, amt);
kunmap_atomic(p);
mark_page_accessed(page);
page_cache_release(page);
copied += amt;
index++;
offset = 0;
} while(copied < size);
(*pos) += size;
return size;
}
/**
* gfs2_readpages - Read a bunch of pages at once
*
* Some notes:
* 1. This is only for readahead, so we can simply ignore any things
* which are slightly inconvenient (such as locking conflicts between
* the page lock and the glock) and return having done no I/O. Its
* obviously not something we'd want to do on too regular a basis.
* Any I/O we ignore at this time will be done via readpage later.
* 2. We don't handle stuffed files here we let readpage do the honours.
* 3. mpage_readpages() does most of the heavy lifting in the common case.
* 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
*/
static int gfs2_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
struct inode *inode = mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct gfs2_holder gh;
int ret;
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
ret = gfs2_glock_nq(&gh);
if (unlikely(ret))
goto out_uninit;
if (!gfs2_is_stuffed(ip))
ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
gfs2_glock_dq(&gh);
out_uninit:
gfs2_holder_uninit(&gh);
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
ret = -EIO;
return ret;
}
/**
* gfs2_write_begin - Begin to write to a file
* @file: The file to write to
* @mapping: The mapping in which to write
* @pos: The file offset at which to start writing
* @len: Length of the write
* @flags: Various flags
* @pagep: Pointer to return the page
* @fsdata: Pointer to return fs data (unused by GFS2)
*
* Returns: errno
*/
static int gfs2_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
struct gfs2_inode *ip = GFS2_I(mapping->host);
struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
int alloc_required;
int error = 0;
struct gfs2_qadata *qa = NULL;
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
unsigned from = pos & (PAGE_CACHE_SIZE - 1);
struct page *page;
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
error = gfs2_glock_nq(&ip->i_gh);
if (unlikely(error))
goto out_uninit;
if (&ip->i_inode == sdp->sd_rindex) {
error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE,
GL_NOCACHE, &m_ip->i_gh);
if (unlikely(error)) {
gfs2_glock_dq(&ip->i_gh);
goto out_uninit;
}
}
alloc_required = gfs2_write_alloc_required(ip, pos, len);
if (alloc_required || gfs2_is_jdata(ip))
gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
if (alloc_required) {
qa = gfs2_qadata_get(ip);
if (!qa) {
error = -ENOMEM;
goto out_unlock;
}
error = gfs2_quota_lock_check(ip);
if (error)
goto out_alloc_put;
error = gfs2_inplace_reserve(ip, data_blocks + ind_blocks);
if (error)
goto out_qunlock;
}
rblocks = RES_DINODE + ind_blocks;
if (gfs2_is_jdata(ip))
rblocks += data_blocks ? data_blocks : 1;
if (ind_blocks || data_blocks)
rblocks += RES_STATFS + RES_QUOTA;
if (&ip->i_inode == sdp->sd_rindex)
rblocks += 2 * RES_STATFS;
if (alloc_required)
rblocks += gfs2_rg_blocks(ip);
error = gfs2_trans_begin(sdp, rblocks,
PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
if (error)
goto out_trans_fail;
error = -ENOMEM;
flags |= AOP_FLAG_NOFS;
page = grab_cache_page_write_begin(mapping, index, flags);
*pagep = page;
if (unlikely(!page))
goto out_endtrans;
if (gfs2_is_stuffed(ip)) {
error = 0;
if (pos + len > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
error = gfs2_unstuff_dinode(ip, page);
if (error == 0)
goto prepare_write;
} else if (!PageUptodate(page)) {
error = stuffed_readpage(ip, page);
}
goto out;
}
prepare_write:
error = __block_write_begin(page, from, len, gfs2_block_map);
out:
if (error == 0)
return 0;
unlock_page(page);
page_cache_release(page);
gfs2_trans_end(sdp);
if (pos + len > ip->i_inode.i_size)
gfs2_trim_blocks(&ip->i_inode);
goto out_trans_fail;
out_endtrans:
gfs2_trans_end(sdp);
out_trans_fail:
if (alloc_required) {
gfs2_inplace_release(ip);
out_qunlock:
gfs2_quota_unlock(ip);
out_alloc_put:
gfs2_qadata_put(ip);
}
out_unlock:
if (&ip->i_inode == sdp->sd_rindex) {
gfs2_glock_dq(&m_ip->i_gh);
gfs2_holder_uninit(&m_ip->i_gh);
}
gfs2_glock_dq(&ip->i_gh);
out_uninit:
gfs2_holder_uninit(&ip->i_gh);
return error;
}
/**
* adjust_fs_space - Adjusts the free space available due to gfs2_grow
* @inode: the rindex inode
*/
static void adjust_fs_space(struct inode *inode)
{
struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
struct buffer_head *m_bh, *l_bh;
u64 fs_total, new_free;
/* Total up the file system space, according to the latest rindex. */
fs_total = gfs2_ri_total(sdp);
if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0)
return;
spin_lock(&sdp->sd_statfs_spin);
gfs2_statfs_change_in(m_sc, m_bh->b_data +
sizeof(struct gfs2_dinode));
if (fs_total > (m_sc->sc_total + l_sc->sc_total))
new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
else
new_free = 0;
spin_unlock(&sdp->sd_statfs_spin);
fs_warn(sdp, "File system extended by %llu blocks.\n",
(unsigned long long)new_free);
gfs2_statfs_change(sdp, new_free, new_free, 0);
if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0)
goto out;
update_statfs(sdp, m_bh, l_bh);
brelse(l_bh);
out:
brelse(m_bh);
}
/**
* gfs2_stuffed_write_end - Write end for stuffed files
* @inode: The inode
* @dibh: The buffer_head containing the on-disk inode
* @pos: The file position
* @len: The length of the write
* @copied: How much was actually copied by the VFS
* @page: The page
*
* This copies the data from the page into the inode block after
* the inode data structure itself.
*
* Returns: errno
*/
static int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh,
loff_t pos, unsigned len, unsigned copied,
struct page *page)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
u64 to = pos + copied;
void *kaddr;
unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode);
BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode)));
kaddr = kmap_atomic(page);
memcpy(buf + pos, kaddr + pos, copied);
memset(kaddr + pos + copied, 0, len - copied);
flush_dcache_page(page);
kunmap_atomic(kaddr);
if (!PageUptodate(page))
SetPageUptodate(page);
unlock_page(page);
page_cache_release(page);
if (copied) {
if (inode->i_size < to)
i_size_write(inode, to);
mark_inode_dirty(inode);
}
if (inode == sdp->sd_rindex) {
adjust_fs_space(inode);
sdp->sd_rindex_uptodate = 0;
}
brelse(dibh);
gfs2_trans_end(sdp);
if (inode == sdp->sd_rindex) {
gfs2_glock_dq(&m_ip->i_gh);
gfs2_holder_uninit(&m_ip->i_gh);
}
gfs2_glock_dq(&ip->i_gh);
gfs2_holder_uninit(&ip->i_gh);
return copied;
}
/**
* gfs2_write_end
* @file: The file to write to
* @mapping: The address space to write to
* @pos: The file position
* @len: The length of the data
* @copied:
* @page: The page that has been written
* @fsdata: The fsdata (unused in GFS2)
*
* The main write_end function for GFS2. We have a separate one for
* stuffed files as they are slightly different, otherwise we just
* put our locking around the VFS provided functions.
*
* Returns: errno
*/
static int gfs2_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct inode *inode = page->mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
struct buffer_head *dibh;
struct gfs2_qadata *qa = ip->i_qadata;
unsigned int from = pos & (PAGE_CACHE_SIZE - 1);
unsigned int to = from + len;
int ret;
BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL);
ret = gfs2_meta_inode_buffer(ip, &dibh);
if (unlikely(ret)) {
unlock_page(page);
page_cache_release(page);
goto failed;
}
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
if (gfs2_is_stuffed(ip))
return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page);
if (!gfs2_is_writeback(ip))
gfs2_page_add_databufs(ip, page, from, to);
ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
if (inode == sdp->sd_rindex) {
adjust_fs_space(inode);
sdp->sd_rindex_uptodate = 0;
}
brelse(dibh);
failed:
gfs2_trans_end(sdp);
if (ip->i_res)
gfs2_inplace_release(ip);
if (qa) {
gfs2_quota_unlock(ip);
gfs2_qadata_put(ip);
}
if (inode == sdp->sd_rindex) {
gfs2_glock_dq(&m_ip->i_gh);
gfs2_holder_uninit(&m_ip->i_gh);
}
gfs2_glock_dq(&ip->i_gh);
gfs2_holder_uninit(&ip->i_gh);
return ret;
}
/**
* gfs2_set_page_dirty - Page dirtying function
* @page: The page to dirty
*
* Returns: 1 if it dirtyed the page, or 0 otherwise
*/
static int gfs2_set_page_dirty(struct page *page)
{
SetPageChecked(page);
return __set_page_dirty_buffers(page);
}
/**
* 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 = GFS2_I(mapping->host);
struct gfs2_holder i_gh;
sector_t dblock = 0;
int error;
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, gfs2_block_map);
gfs2_glock_dq_uninit(&i_gh);
return dblock;
}
static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
struct gfs2_bufdata *bd;
lock_buffer(bh);
gfs2_log_lock(sdp);
clear_buffer_dirty(bh);
bd = bh->b_private;
if (bd) {
if (!list_empty(&bd->bd_le.le_list) && !buffer_pinned(bh))
list_del_init(&bd->bd_le.le_list);
else
gfs2_remove_from_journal(bh, current->journal_info, 0);
}
bh->b_bdev = NULL;
clear_buffer_mapped(bh);
clear_buffer_req(bh);
clear_buffer_new(bh);
gfs2_log_unlock(sdp);
unlock_buffer(bh);
}
static void gfs2_invalidatepage(struct page *page, unsigned long offset)
{
struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
struct buffer_head *bh, *head;
unsigned long pos = 0;
BUG_ON(!PageLocked(page));
if (offset == 0)
ClearPageChecked(page);
if (!page_has_buffers(page))
goto out;
bh = head = page_buffers(page);
do {
if (offset <= pos)
gfs2_discard(sdp, bh);
pos += bh->b_size;
bh = bh->b_this_page;
} while (bh != head);
out:
if (offset == 0)
try_to_release_page(page, 0);
}
/**
* gfs2_ok_for_dio - check that dio is valid on this file
* @ip: The inode
* @rw: READ or WRITE
* @offset: The offset at which we are reading or writing
*
* Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
* 1 (to accept the i/o request)
*/
static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
{
/*
* Should we return an error here? I can't see that O_DIRECT for
* a stuffed file makes any sense. For now we'll silently fall
* back to buffered I/O
*/
if (gfs2_is_stuffed(ip))
return 0;
if (offset >= i_size_read(&ip->i_inode))
return 0;
return 1;
}
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 = GFS2_I(inode);
struct gfs2_holder gh;
int rv;
/*
* Deferred lock, even if its a write, since we do no allocation
* on this path. All we need change is atime, and this lock mode
* ensures that other nodes have flushed their buffered read caches
* (i.e. their page cache entries for this inode). We do not,
* unfortunately have the option of only flushing a range like
* the VFS does.
*/
gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
rv = gfs2_glock_nq(&gh);
if (rv)
return rv;
rv = gfs2_ok_for_dio(ip, rw, offset);
if (rv != 1)
goto out; /* dio not valid, fall back to buffered i/o */
rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
offset, nr_segs, gfs2_get_block_direct,
NULL, NULL, 0);
out:
gfs2_glock_dq_m(1, &gh);
gfs2_holder_uninit(&gh);
return rv;
}
/**
* gfs2_releasepage - free the metadata associated with a page
* @page: the page that's being released
* @gfp_mask: passed from Linux VFS, ignored by us
*
* Call try_to_free_buffers() if the buffers in this page can be
* released.
*
* Returns: 0
*/
int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
{
struct address_space *mapping = page->mapping;
struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
struct buffer_head *bh, *head;
struct gfs2_bufdata *bd;
if (!page_has_buffers(page))
return 0;
gfs2_log_lock(sdp);
spin_lock(&sdp->sd_ail_lock);
head = bh = page_buffers(page);
do {
if (atomic_read(&bh->b_count))
goto cannot_release;
bd = bh->b_private;
if (bd && bd->bd_ail)
goto cannot_release;
if (buffer_pinned(bh) || buffer_dirty(bh))
goto not_possible;
bh = bh->b_this_page;
} while(bh != head);
spin_unlock(&sdp->sd_ail_lock);
gfs2_log_unlock(sdp);
head = bh = page_buffers(page);
do {
gfs2_log_lock(sdp);
bd = bh->b_private;
if (bd) {
gfs2_assert_warn(sdp, bd->bd_bh == bh);
gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
if (!list_empty(&bd->bd_le.le_list)) {
if (!buffer_pinned(bh))
list_del_init(&bd->bd_le.le_list);
else
bd = NULL;
}
if (bd)
bd->bd_bh = NULL;
bh->b_private = NULL;
}
gfs2_log_unlock(sdp);
if (bd)
kmem_cache_free(gfs2_bufdata_cachep, bd);
bh = bh->b_this_page;
} while (bh != head);
return try_to_free_buffers(page);
not_possible: /* Should never happen */
WARN_ON(buffer_dirty(bh));
WARN_ON(buffer_pinned(bh));
cannot_release:
spin_unlock(&sdp->sd_ail_lock);
gfs2_log_unlock(sdp);
return 0;
}
static const struct address_space_operations gfs2_writeback_aops = {
.writepage = gfs2_writeback_writepage,
.writepages = gfs2_writeback_writepages,
.readpage = gfs2_readpage,
.readpages = gfs2_readpages,
.write_begin = gfs2_write_begin,
.write_end = gfs2_write_end,
.bmap = gfs2_bmap,
.invalidatepage = gfs2_invalidatepage,
.releasepage = gfs2_releasepage,
.direct_IO = gfs2_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations gfs2_ordered_aops = {
.writepage = gfs2_ordered_writepage,
.readpage = gfs2_readpage,
.readpages = gfs2_readpages,
.write_begin = gfs2_write_begin,
.write_end = gfs2_write_end,
.set_page_dirty = gfs2_set_page_dirty,
.bmap = gfs2_bmap,
.invalidatepage = gfs2_invalidatepage,
.releasepage = gfs2_releasepage,
.direct_IO = gfs2_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};
static const struct address_space_operations gfs2_jdata_aops = {
.writepage = gfs2_jdata_writepage,
.writepages = gfs2_jdata_writepages,
.readpage = gfs2_readpage,
.readpages = gfs2_readpages,
.write_begin = gfs2_write_begin,
.write_end = gfs2_write_end,
.set_page_dirty = gfs2_set_page_dirty,
.bmap = gfs2_bmap,
.invalidatepage = gfs2_invalidatepage,
.releasepage = gfs2_releasepage,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};
void gfs2_set_aops(struct inode *inode)
{
struct gfs2_inode *ip = GFS2_I(inode);
if (gfs2_is_writeback(ip))
inode->i_mapping->a_ops = &gfs2_writeback_aops;
else if (gfs2_is_ordered(ip))
inode->i_mapping->a_ops = &gfs2_ordered_aops;
else if (gfs2_is_jdata(ip))
inode->i_mapping->a_ops = &gfs2_jdata_aops;
else
BUG();
}
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