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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 <linux/uio.h>
#include <trace/events/writeback.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"
static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
unsigned int from, unsigned int len)
{
struct buffer_head *head = page_buffers(page);
unsigned int bsize = head->b_size;
struct buffer_head *bh;
unsigned int to = from + len;
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)
continue;
if (start >= to)
break;
set_buffer_uptodate(bh);
gfs2_trans_add_data(ip->i_gl, bh);
}
}
/**
* 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_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_SIZE-1);
if (page->index > end_index || (page->index == end_index && !offset)) {
page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
goto out;
}
return 1;
redirty:
redirty_page_for_writepage(wbc, page);
out:
unlock_page(page);
return 0;
}
/**
* gfs2_writepage - Write page for writeback mappings
* @page: The page
* @wbc: The writeback control
*
*/
static int gfs2_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);
}
/* This is the same as calling block_write_full_page, but it also
* writes pages outside of i_size
*/
static int gfs2_write_full_page(struct page *page, get_block_t *get_block,
struct writeback_control *wbc)
{
struct inode * const inode = page->mapping->host;
loff_t i_size = i_size_read(inode);
const pgoff_t end_index = i_size >> PAGE_SHIFT;
unsigned offset;
/*
* The page straddles i_size. It must be zeroed out on each and every
* writepage invocation because it may be mmapped. "A file is mapped
* in multiples of the page size. For a file that is not a multiple of
* the page size, the remaining memory is zeroed when mapped, and
* writes to that region are not written out to the file."
*/
offset = i_size & (PAGE_SIZE-1);
if (page->index == end_index && offset)
zero_user_segment(page, offset, PAGE_SIZE);
return __block_write_full_page(inode, page, get_block, wbc,
end_buffer_async_write);
}
/**
* __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,
BIT(BH_Dirty)|BIT(BH_Uptodate));
}
gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize);
}
return gfs2_write_full_page(page, gfs2_get_block_noalloc, wbc);
}
/**
* gfs2_jdata_writepage - Write complete page
* @page: Page to write
* @wbc: The writeback control
*
* Returns: errno
*
*/
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);
int ret;
if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
goto out;
if (PageChecked(page) || current->journal_info)
goto out_ignore;
ret = __gfs2_jdata_writepage(page, wbc);
return ret;
out_ignore:
redirty_page_for_writepage(wbc, page);
out:
unlock_page(page);
return 0;
}
/**
* gfs2_writepages - Write a bunch of dirty pages back to disk
* @mapping: The mapping to write
* @wbc: Write-back control
*
* Used for both ordered and writeback modes.
*/
static int gfs2_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
int ret = mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
/*
* Even if we didn't write any pages here, we might still be holding
* dirty pages in the ail. We forcibly flush the ail because we don't
* want balance_dirty_pages() to loop indefinitely trying to write out
* pages held in the ail that it can't find.
*/
if (ret == 0)
set_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags);
return ret;
}
/**
* gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
* @mapping: The mapping
* @wbc: The writeback control
* @pvec: The vector of pages
* @nr_pages: The number of pages to write
* @done_index: Page index
*
* 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 *done_index)
{
struct inode *inode = mapping->host;
struct gfs2_sbd *sdp = GFS2_SB(inode);
unsigned nrblocks = nr_pages * (PAGE_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];
*done_index = page->index;
lock_page(page);
if (unlikely(page->mapping != mapping)) {
continue_unlock:
unlock_page(page);
continue;
}
if (!PageDirty(page)) {
/* someone wrote it for us */
goto continue_unlock;
}
if (PageWriteback(page)) {
if (wbc->sync_mode != WB_SYNC_NONE)
wait_on_page_writeback(page);
else
goto continue_unlock;
}
BUG_ON(PageWriteback(page));
if (!clear_page_dirty_for_io(page))
goto continue_unlock;
trace_wbc_writepage(wbc, inode_to_bdi(inode));
ret = __gfs2_jdata_writepage(page, wbc);
if (unlikely(ret)) {
if (ret == AOP_WRITEPAGE_ACTIVATE) {
unlock_page(page);
ret = 0;
} else {
/*
* done_index is set past this page,
* so media errors will not choke
* background writeout for the entire
* file. This has consequences for
* range_cyclic semantics (ie. it may
* not be suitable for data integrity
* writeout).
*/
*done_index = page->index + 1;
ret = 1;
break;
}
}
/*
* We stop writing back only if we are not doing
* integrity sync. In case of integrity sync we have to
* keep going until we have written all the pages
* we tagged for writeback prior to entering this loop.
*/
if (--wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) {
ret = 1;
break;
}
}
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
*
* 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 uninitialized_var(writeback_index);
pgoff_t index;
pgoff_t end;
pgoff_t done_index;
int cycled;
int range_whole = 0;
int tag;
pagevec_init(&pvec);
if (wbc->range_cyclic) {
writeback_index = mapping->writeback_index; /* prev offset */
index = writeback_index;
if (index == 0)
cycled = 1;
else
cycled = 0;
end = -1;
} else {
index = wbc->range_start >> PAGE_SHIFT;
end = wbc->range_end >> PAGE_SHIFT;
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
cycled = 1; /* ignore range_cyclic tests */
}
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag = PAGECACHE_TAG_TOWRITE;
else
tag = PAGECACHE_TAG_DIRTY;
retry:
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag_pages_for_writeback(mapping, index, end);
done_index = index;
while (!done && (index <= end)) {
nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
tag);
if (nr_pages == 0)
break;
ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, &done_index);
if (ret)
done = 1;
if (ret > 0)
ret = 0;
pagevec_release(&pvec);
cond_resched();
}
if (!cycled && !done) {
/*
* range_cyclic:
* We hit the last page and there is more work to be done: wrap
* back to the start of the file
*/
cycled = 1;
index = 0;
end = writeback_index - 1;
goto retry;
}
if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
mapping->writeback_index = done_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, GFS2_LOG_HEAD_FLUSH_NORMAL |
GFS2_LFC_JDATA_WPAGES);
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_SIZE);
SetPageUptodate(page);
return 0;
}
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
return error;
kaddr = kmap_atomic(page);
if (dsize > gfs2_max_stuffed_size(ip))
dsize = gfs2_max_stuffed_size(ip);
memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
memset(kaddr + dsize, 0, PAGE_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. It's used by the internal file
* reading code as in that case we already hold the glock. Also it's
* 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
* @buf: The buffer to fill
* @pos: The file position
* @size: The amount to read
*
*/
int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
unsigned size)
{
struct address_space *mapping = ip->i_inode.i_mapping;
unsigned long index = *pos / PAGE_SIZE;
unsigned offset = *pos & (PAGE_SIZE - 1);
unsigned copied = 0;
unsigned amt;
struct page *page;
void *p;
do {
amt = size - copied;
if (offset + size > PAGE_SIZE)
amt = PAGE_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);
put_page(page);
copied += amt;
index++;
offset = 0;
} while(copied < size);
(*pos) += size;
return size;
}
/**
* gfs2_readpages - Read a bunch of pages at once
* @file: The file to read from
* @mapping: Address space info
* @pages: List of pages to read
* @nr_pages: Number of pages to read
*
* 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;
unsigned requested = 0;
int alloc_required;
int error = 0;
pgoff_t index = pos >> PAGE_SHIFT;
unsigned from = pos & (PAGE_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) {
struct gfs2_alloc_parms ap = { .aflags = 0, };
requested = data_blocks + ind_blocks;
ap.target = requested;
error = gfs2_quota_lock_check(ip, &ap);
if (error)
goto out_unlock;
error = gfs2_inplace_reserve(ip, &ap);
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, requested);
error = gfs2_trans_begin(sdp, rblocks,
PAGE_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 > gfs2_max_stuffed_size(ip)) {
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);
put_page(page);
gfs2_trans_end(sdp);
if (alloc_required) {
gfs2_inplace_release(ip);
if (pos + len > ip->i_inode.i_size)
gfs2_trim_blocks(&ip->i_inode);
}
goto out_qunlock;
out_endtrans:
gfs2_trans_end(sdp);
out_trans_fail:
if (alloc_required)
gfs2_inplace_release(ip);
out_qunlock:
if (alloc_required)
gfs2_quota_unlock(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
* @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 copied,
struct page *page)
{
struct gfs2_inode *ip = GFS2_I(inode);
u64 to = pos + copied;
void *kaddr;
unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode);
BUG_ON(pos + copied > gfs2_max_stuffed_size(ip));
kaddr = kmap_atomic(page);
memcpy(buf + pos, kaddr + pos, copied);
flush_dcache_page(page);
kunmap_atomic(kaddr);
WARN_ON(!PageUptodate(page));
unlock_page(page);
put_page(page);
if (copied) {
if (inode->i_size < to)
i_size_write(inode, to);
mark_inode_dirty(inode);
}
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: How much was actually copied by the VFS
* @page: The page that has been written
* @fsdata: The fsdata (unused in GFS2)
*
* The main write_end function for GFS2. 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;
int ret;
struct gfs2_trans *tr = current->journal_info;
BUG_ON(!tr);
BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL);
ret = gfs2_meta_inode_buffer(ip, &dibh);
if (unlikely(ret))
goto out;
if (gfs2_is_stuffed(ip)) {
ret = gfs2_stuffed_write_end(inode, dibh, pos, copied, page);
page = NULL;
goto out2;
}
if (gfs2_is_jdata(ip))
gfs2_page_add_databufs(ip, page, pos & ~PAGE_MASK, len);
else
gfs2_ordered_add_inode(ip);
ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
page = NULL;
if (tr->tr_num_buf_new)
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
else
gfs2_trans_add_meta(ip->i_gl, dibh);
out2:
if (inode == sdp->sd_rindex) {
adjust_fs_space(inode);
sdp->sd_rindex_uptodate = 0;
}
brelse(dibh);
out:
if (page) {
unlock_page(page);
put_page(page);
}
gfs2_trans_end(sdp);
gfs2_inplace_release(ip);
if (ip->i_qadata && ip->i_qadata->qa_qd_num)
gfs2_quota_unlock(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;
}
/**
* jdata_set_page_dirty - Page dirtying function
* @page: The page to dirty
*
* Returns: 1 if it dirtyed the page, or 0 otherwise
*/
static int jdata_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_list) && !buffer_pinned(bh))
list_del_init(&bd->bd_list);
else
gfs2_remove_from_journal(bh, REMOVE_JDATA);
}
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 int offset,
unsigned int length)
{
struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
unsigned int stop = offset + length;
int partial_page = (offset || length < PAGE_SIZE);
struct buffer_head *bh, *head;
unsigned long pos = 0;
BUG_ON(!PageLocked(page));
if (!partial_page)
ClearPageChecked(page);
if (!page_has_buffers(page))
goto out;
bh = head = page_buffers(page);
do {
if (pos + bh->b_size > stop)
return;
if (offset <= pos)
gfs2_discard(sdp, bh);
pos += bh->b_size;
bh = bh->b_this_page;
} while (bh != head);
out:
if (!partial_page)
try_to_release_page(page, 0);
}
/**
* gfs2_ok_for_dio - check that dio is valid on this file
* @ip: The inode
* @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, 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(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct address_space *mapping = inode->i_mapping;
struct gfs2_inode *ip = GFS2_I(inode);
loff_t offset = iocb->ki_pos;
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)
goto out_uninit;
rv = gfs2_ok_for_dio(ip, offset);
if (rv != 1)
goto out; /* dio not valid, fall back to buffered i/o */
/*
* Now since we are holding a deferred (CW) lock at this point, you
* might be wondering why this is ever needed. There is a case however
* where we've granted a deferred local lock against a cached exclusive
* glock. That is ok provided all granted local locks are deferred, but
* it also means that it is possible to encounter pages which are
* cached and possibly also mapped. So here we check for that and sort
* them out ahead of the dio. The glock state machine will take care of
* everything else.
*
* If in fact the cached glock state (gl->gl_state) is deferred (CW) in
* the first place, mapping->nr_pages will always be zero.
*/
if (mapping->nrpages) {
loff_t lstart = offset & ~(PAGE_SIZE - 1);
loff_t len = iov_iter_count(iter);
loff_t end = PAGE_ALIGN(offset + len) - 1;
rv = 0;
if (len == 0)
goto out;
if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
unmap_shared_mapping_range(ip->i_inode.i_mapping, offset, len);
rv = filemap_write_and_wait_range(mapping, lstart, end);
if (rv)
goto out;
if (iov_iter_rw(iter) == WRITE)
truncate_inode_pages_range(mapping, lstart, end);
}
rv = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
gfs2_get_block_direct, NULL, NULL, 0);
out:
gfs2_glock_dq(&gh);
out_uninit:
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;
/*
* From xfs_vm_releasepage: mm accommodates an old ext3 case where
* clean pages might not have had the dirty bit cleared. Thus, it can
* send actual dirty pages to ->releasepage() via shrink_active_list().
*
* As a workaround, we skip pages that contain dirty buffers below.
* Once ->releasepage isn't called on dirty pages anymore, we can warn
* on dirty buffers like we used to here again.
*/
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_tr)
goto cannot_release;
if (buffer_dirty(bh) || WARN_ON(buffer_pinned(bh)))
goto cannot_release;
bh = bh->b_this_page;
} while(bh != head);
spin_unlock(&sdp->sd_ail_lock);
head = bh = page_buffers(page);
do {
bd = bh->b_private;
if (bd) {
gfs2_assert_warn(sdp, bd->bd_bh == bh);
if (!list_empty(&bd->bd_list))
list_del_init(&bd->bd_list);
bd->bd_bh = NULL;
bh->b_private = NULL;
kmem_cache_free(gfs2_bufdata_cachep, bd);
}
bh = bh->b_this_page;
} while (bh != head);
gfs2_log_unlock(sdp);
return try_to_free_buffers(page);
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_writepage,
.writepages = gfs2_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_writepage,
.writepages = gfs2_writepages,
.readpage = gfs2_readpage,
.readpages = gfs2_readpages,
.write_begin = gfs2_write_begin,
.write_end = gfs2_write_end,
.set_page_dirty = __set_page_dirty_buffers,
.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 = jdata_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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