- 根目录:
- fs
- gfs2
- meta_io.c
/*
* 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/mm.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>
#include <linux/swap.h>
#include <linux/delay.h>
#include <linux/bio.h>
#include <linux/gfs2_ondisk.h>
#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "log.h"
#include "lops.h"
#include "meta_io.h"
#include "rgrp.h"
#include "trans.h"
#include "util.h"
#include "trace_gfs2.h"
static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc)
{
struct buffer_head *bh, *head;
int nr_underway = 0;
int write_op = REQ_META | REQ_PRIO |
(wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
BUG_ON(!PageLocked(page));
BUG_ON(!page_has_buffers(page));
head = page_buffers(page);
bh = head;
do {
if (!buffer_mapped(bh))
continue;
/*
* If it's a fully non-blocking write attempt and we cannot
* lock the buffer then redirty the page. Note that this can
* potentially cause a busy-wait loop from pdflush and kswapd
* activity, but those code paths have their own higher-level
* throttling.
*/
if (wbc->sync_mode != WB_SYNC_NONE) {
lock_buffer(bh);
} else if (!trylock_buffer(bh)) {
redirty_page_for_writepage(wbc, page);
continue;
}
if (test_clear_buffer_dirty(bh)) {
mark_buffer_async_write(bh);
} else {
unlock_buffer(bh);
}
} while ((bh = bh->b_this_page) != head);
/*
* The page and its buffers are protected by PageWriteback(), so we can
* drop the bh refcounts early.
*/
BUG_ON(PageWriteback(page));
set_page_writeback(page);
do {
struct buffer_head *next = bh->b_this_page;
if (buffer_async_write(bh)) {
submit_bh(write_op, bh);
nr_underway++;
}
bh = next;
} while (bh != head);
unlock_page(page);
if (nr_underway == 0)
end_page_writeback(page);
return 0;
}
const struct address_space_operations gfs2_meta_aops = {
.writepage = gfs2_aspace_writepage,
.releasepage = gfs2_releasepage,
};
/**
* gfs2_meta_sync - Sync all buffers associated with a glock
* @gl: The glock
*
*/
void gfs2_meta_sync(struct gfs2_glock *gl)
{
struct address_space *mapping = gfs2_glock2aspace(gl);
int error;
filemap_fdatawrite(mapping);
error = filemap_fdatawait(mapping);
if (error)
gfs2_io_error(gl->gl_sbd);
}
/**
* gfs2_getbuf - Get a buffer with a given address space
* @gl: the glock
* @blkno: the block number (filesystem scope)
* @create: 1 if the buffer should be created
*
* Returns: the buffer
*/
struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create)
{
struct address_space *mapping = gfs2_glock2aspace(gl);
struct gfs2_sbd *sdp = gl->gl_sbd;
struct page *page;
struct buffer_head *bh;
unsigned int shift;
unsigned long index;
unsigned int bufnum;
shift = PAGE_CACHE_SHIFT - sdp->sd_sb.sb_bsize_shift;
index = blkno >> shift; /* convert block to page */
bufnum = blkno - (index << shift); /* block buf index within page */
if (create) {
for (;;) {
page = grab_cache_page(mapping, index);
if (page)
break;
yield();
}
} else {
page = find_lock_page(mapping, index);
if (!page)
return NULL;
}
if (!page_has_buffers(page))
create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0);
/* Locate header for our buffer within our page */
for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
/* Do nothing */;
get_bh(bh);
if (!buffer_mapped(bh))
map_bh(bh, sdp->sd_vfs, blkno);
unlock_page(page);
mark_page_accessed(page);
page_cache_release(page);
return bh;
}
static void meta_prep_new(struct buffer_head *bh)
{
struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data;
lock_buffer(bh);
clear_buffer_dirty(bh);
set_buffer_uptodate(bh);
unlock_buffer(bh);
mh->mh_magic = cpu_to_be32(GFS2_MAGIC);
}
/**
* gfs2_meta_new - Get a block
* @gl: The glock associated with this block
* @blkno: The block number
*
* Returns: The buffer
*/
struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno)
{
struct buffer_head *bh;
bh = gfs2_getbuf(gl, blkno, CREATE);
meta_prep_new(bh);
return bh;
}
/**
* gfs2_meta_read - Read a block from disk
* @gl: The glock covering the block
* @blkno: The block number
* @flags: flags
* @bhp: the place where the buffer is returned (NULL on failure)
*
* Returns: errno
*/
int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
struct buffer_head **bhp)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct buffer_head *bh;
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
return -EIO;
*bhp = bh = gfs2_getbuf(gl, blkno, CREATE);
lock_buffer(bh);
if (buffer_uptodate(bh)) {
unlock_buffer(bh);
return 0;
}
bh->b_end_io = end_buffer_read_sync;
get_bh(bh);
submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
if (!(flags & DIO_WAIT))
return 0;
wait_on_buffer(bh);
if (unlikely(!buffer_uptodate(bh))) {
struct gfs2_trans *tr = current->journal_info;
if (tr && tr->tr_touched)
gfs2_io_error_bh(sdp, bh);
brelse(bh);
return -EIO;
}
return 0;
}
/**
* gfs2_meta_wait - Reread a block from disk
* @sdp: the filesystem
* @bh: The block to wait for
*
* Returns: errno
*/
int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
{
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
return -EIO;
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
struct gfs2_trans *tr = current->journal_info;
if (tr && tr->tr_touched)
gfs2_io_error_bh(sdp, bh);
return -EIO;
}
if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
return -EIO;
return 0;
}
/**
* gfs2_attach_bufdata - attach a struct gfs2_bufdata structure to a buffer
* @gl: the glock the buffer belongs to
* @bh: The buffer to be attached to
* @meta: Flag to indicate whether its metadata or not
*/
void gfs2_attach_bufdata(struct gfs2_glock *gl, struct buffer_head *bh,
int meta)
{
struct gfs2_bufdata *bd;
if (meta)
lock_page(bh->b_page);
if (bh->b_private) {
if (meta)
unlock_page(bh->b_page);
return;
}
bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL);
bd->bd_bh = bh;
bd->bd_gl = gl;
INIT_LIST_HEAD(&bd->bd_list_tr);
if (meta)
lops_init_le(&bd->bd_le, &gfs2_buf_lops);
else
lops_init_le(&bd->bd_le, &gfs2_databuf_lops);
bh->b_private = bd;
if (meta)
unlock_page(bh->b_page);
}
void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int meta)
{
struct address_space *mapping = bh->b_page->mapping;
struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
struct gfs2_bufdata *bd = bh->b_private;
if (test_clear_buffer_pinned(bh)) {
trace_gfs2_pin(bd, 0);
atomic_dec(&sdp->sd_log_pinned);
list_del_init(&bd->bd_le.le_list);
if (meta) {
gfs2_assert_warn(sdp, sdp->sd_log_num_buf);
sdp->sd_log_num_buf--;
tr->tr_num_buf_rm++;
} else {
gfs2_assert_warn(sdp, sdp->sd_log_num_databuf);
sdp->sd_log_num_databuf--;
tr->tr_num_databuf_rm++;
}
tr->tr_touched = 1;
brelse(bh);
}
if (bd) {
spin_lock(&sdp->sd_ail_lock);
if (bd->bd_ail) {
gfs2_remove_from_ail(bd);
bh->b_private = NULL;
bd->bd_bh = NULL;
bd->bd_blkno = bh->b_blocknr;
gfs2_trans_add_revoke(sdp, bd);
}
spin_unlock(&sdp->sd_ail_lock);
}
clear_buffer_dirty(bh);
clear_buffer_uptodate(bh);
}
/**
* gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore
* @ip: the inode who owns the buffers
* @bstart: the first buffer in the run
* @blen: the number of buffers in the run
*
*/
void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct buffer_head *bh;
while (blen) {
bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE);
if (bh) {
lock_buffer(bh);
gfs2_log_lock(sdp);
gfs2_remove_from_journal(bh, current->journal_info, 1);
gfs2_log_unlock(sdp);
unlock_buffer(bh);
brelse(bh);
}
bstart++;
blen--;
}
}
/**
* gfs2_meta_indirect_buffer - Get a metadata buffer
* @ip: The GFS2 inode
* @height: The level of this buf in the metadata (indir addr) tree (if any)
* @num: The block number (device relative) of the buffer
* @new: Non-zero if we may create a new buffer
* @bhp: the buffer is returned here
*
* Returns: errno
*/
int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num,
int new, struct buffer_head **bhp)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct gfs2_glock *gl = ip->i_gl;
struct buffer_head *bh;
int ret = 0;
if (new) {
BUG_ON(height == 0);
bh = gfs2_meta_new(gl, num);
gfs2_trans_add_bh(ip->i_gl, bh, 1);
gfs2_metatype_set(bh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header));
} else {
u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI;
ret = gfs2_meta_read(gl, num, DIO_WAIT, &bh);
if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) {
brelse(bh);
ret = -EIO;
}
}
*bhp = bh;
return ret;
}
/**
* gfs2_meta_ra - start readahead on an extent of a file
* @gl: the glock the blocks belong to
* @dblock: the starting disk block
* @extlen: the number of blocks in the extent
*
* returns: the first buffer in the extent
*/
struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct buffer_head *first_bh, *bh;
u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >>
sdp->sd_sb.sb_bsize_shift;
BUG_ON(!extlen);
if (max_ra < 1)
max_ra = 1;
if (extlen > max_ra)
extlen = max_ra;
first_bh = gfs2_getbuf(gl, dblock, CREATE);
if (buffer_uptodate(first_bh))
goto out;
if (!buffer_locked(first_bh))
ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
dblock++;
extlen--;
while (extlen) {
bh = gfs2_getbuf(gl, dblock, CREATE);
if (!buffer_uptodate(bh) && !buffer_locked(bh))
ll_rw_block(READA | REQ_META, 1, &bh);
brelse(bh);
dblock++;
extlen--;
if (!buffer_locked(first_bh) && buffer_uptodate(first_bh))
goto out;
}
wait_on_buffer(first_bh);
out:
return first_bh;
}