C++ buffer_uptodate函数代码示例

static int
adfs_fplus_sync(struct adfs_dir *dir)
{
	int err = 0;
	int i;

	for (i = dir->nr_buffers - 1; i >= 0; i--) {
		struct buffer_head *bh = dir->bh[i];
		sync_dirty_buffer(bh);
		if (buffer_req(bh) && !buffer_uptodate(bh))
			err = -EIO;
	}

	return err;
}

int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *bh)
{
	wait_on_buffer(bh);
	if (!buffer_uptodate(bh))
		return -EIO;
	if (buffer_dirty(bh))
		return -EEXIST;

	if (buffer_nilfs_node(bh) && nilfs_btree_broken_node_block(bh)) {
		clear_buffer_uptodate(bh);
		return -EIO;
	}
	mark_buffer_dirty(bh);
	return 0;
}

int ocfs2_write_block(struct ocfs2_super *osb, struct buffer_head *bh,
		      struct inode *inode)
{
	int ret = 0;

	mlog_entry("(bh->b_blocknr = %llu, inode=%p)\n",
		   (unsigned long long)bh->b_blocknr, inode);

	BUG_ON(bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO);
	BUG_ON(buffer_jbd(bh));

	/* No need to check for a soft readonly file system here. non
	 * journalled writes are only ever done on system files which
	 * can get modified during recovery even if read-only. */
	if (ocfs2_is_hard_readonly(osb)) {
		ret = -EROFS;
		goto out;
	}

	mutex_lock(&OCFS2_I(inode)->ip_io_mutex);

	lock_buffer(bh);
	set_buffer_uptodate(bh);

	/* remove from dirty list before I/O. */
	clear_buffer_dirty(bh);

	get_bh(bh); /* for end_buffer_write_sync() */
	bh->b_end_io = end_buffer_write_sync;
	submit_bh(WRITE, bh);

	wait_on_buffer(bh);

	if (buffer_uptodate(bh)) {
		ocfs2_set_buffer_uptodate(inode, bh);
	} else {
		/* We don't need to remove the clustered uptodate
		 * information for this bh as it's not marked locally
		 * uptodate. */
		ret = -EIO;
		put_bh(bh);
	}

	mutex_unlock(&OCFS2_I(inode)->ip_io_mutex);
out:
	mlog_exit(ret);
	return ret;
}

int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
				 handle_t *handle, struct inode *inode,
				 struct buffer_head *bh)
{
	int err = 0;

	might_sleep();

	set_buffer_meta(bh);
	set_buffer_prio(bh);
	if (ext4_handle_valid(handle)) {
		err = jbd2_journal_dirty_metadata(handle, bh);
		/* Errors can only happen if there is a bug */
		if (WARN_ON_ONCE(err)) {
			ext4_journal_abort_handle(where, line, __func__, bh,
						  handle, err);
			ext4_error_inode(inode, where, line,
					 bh->b_blocknr,
					 "journal_dirty_metadata failed: "
					 "handle type %u started at line %u, "
					 "credits %u/%u, errcode %d",
					 handle->h_type,
					 handle->h_line_no,
					 handle->h_requested_credits,
					 handle->h_buffer_credits, err);
		}
	} else {
		if (inode)
			mark_buffer_dirty_inode(bh, inode);
		else
			mark_buffer_dirty(bh);
		if (inode && inode_needs_sync(inode)) {
			sync_dirty_buffer(bh);
			if (buffer_req(bh) && !buffer_uptodate(bh)) {
				struct ext4_super_block *es;

				es = EXT4_SB(inode->i_sb)->s_es;
				es->s_last_error_block =
					cpu_to_le64(bh->b_blocknr);
				ext4_error_inode(inode, where, line,
						 bh->b_blocknr,
					"IO error syncing itable block");
				err = -EIO;
			}
		}
	}
	return err;
}

void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
{
	struct buffer_head *bh;
	/*return hpfs_map_sector(s, secno, bhp, 0);*/

	cond_resched();

	if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
		if (!buffer_uptodate(bh)) wait_on_buffer(bh);
		set_buffer_uptodate(bh);
		return bh->b_data;
	} else {
		printk("HPFS: hpfs_get_sector: getblk failed\n");
		return NULL;
	}
}

int ocfs2_write_block(struct ocfs2_super *osb, struct buffer_head *bh,
		      struct ocfs2_caching_info *ci)
{
	int ret = 0;

	trace_ocfs2_write_block((unsigned long long)bh->b_blocknr, ci);

	BUG_ON(bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO);
	BUG_ON(buffer_jbd(bh));

	/* No need to check for a soft readonly file system here. non
	 * journalled writes are only ever done on system files which
	 * can get modified during recovery even if read-only. */
	if (ocfs2_is_hard_readonly(osb)) {
		ret = -EROFS;
		mlog_errno(ret);
		goto out;
	}

	ocfs2_metadata_cache_io_lock(ci);

	lock_buffer(bh);
	set_buffer_uptodate(bh);

	/* remove from dirty list before I/O. */
	clear_buffer_dirty(bh);

	get_bh(bh); /* for end_buffer_write_sync() */
	bh->b_end_io = end_buffer_write_sync;
	submit_bh(REQ_OP_WRITE, 0, bh);

	wait_on_buffer(bh);

	if (buffer_uptodate(bh)) {
		ocfs2_set_buffer_uptodate(ci, bh);
	} else {
		/* We don't need to remove the clustered uptodate
		 * information for this bh as it's not marked locally
		 * uptodate. */
		ret = -EIO;
		mlog_errno(ret);
	}

	ocfs2_metadata_cache_io_unlock(ci);
out:
	return ret;
}

/*
 * Read the MMP block. It _must_ be read from disk and hence we clear the
 * uptodate flag on the buffer.
 */
static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
			  ext4_fsblk_t mmp_block)
{
	struct mmp_struct *mmp;
	int ret;

	if (*bh)
		clear_buffer_uptodate(*bh);

	/* This would be sb_bread(sb, mmp_block), except we need to be sure
	 * that the MD RAID device cache has been bypassed, and that the read
	 * is not blocked in the elevator. */
	if (!*bh) {
		*bh = sb_getblk(sb, mmp_block);
		if (!*bh) {
			ret = -ENOMEM;
			goto warn_exit;
		}
	}

	get_bh(*bh);
	lock_buffer(*bh);
	(*bh)->b_end_io = end_buffer_read_sync;
	submit_bh(READ_SYNC | REQ_META | REQ_PRIO, *bh);
	wait_on_buffer(*bh);
	if (!buffer_uptodate(*bh)) {
		ret = -EIO;
		goto warn_exit;
	}
	mmp = (struct mmp_struct *)((*bh)->b_data);
	if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC) {
		ret = -EFSCORRUPTED;
		goto warn_exit;
	}
	if (!ext4_mmp_csum_verify(sb, mmp)) {
		ret = -EFSBADCRC;
		goto warn_exit;
	}
	return 0;
warn_exit:
	brelse(*bh);
	*bh = NULL;
	ext4_warning(sb, "Error %d while reading MMP block %llu",
		     ret, mmp_block);
	return ret;
}

int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
		   struct buffer_head **bhp)
{
	*bhp = gfs2_getbuf(gl, blkno, CREATE);
	if (!buffer_uptodate(*bhp)) {
		ll_rw_block(READ_META, 1, bhp);
		if (flags & DIO_WAIT) {
			int error = gfs2_meta_wait(gl->gl_sbd, *bhp);
			if (error) {
				brelse(*bhp);
				return error;
			}
		}
	}

	return 0;
}

/* Clear buffer dirty for I/O (Caller must remove buffer from list) */
static void tux3_clear_buffer_dirty_for_io(struct buffer_head *buffer,
					   struct sb *sb, block_t block)
{
	assert(list_empty(&buffer->b_assoc_buffers));
	assert(buffer_dirty(buffer));	/* Who cleared the dirty? */
	/* If buffer was hole and dirtied, it can be !buffer_mapped() */
	/*assert(buffer_mapped(buffer));*/
	assert(buffer_uptodate(buffer));

	/* Set up buffer for I/O. FIXME: need? */
	map_bh(buffer, vfs_sb(sb), block);
	clear_buffer_delay(buffer);

	/*buffer->b_assoc_map = NULL;*/	/* FIXME: hack for *_for_io_hack */
	tux3_clear_bufdelta(buffer);	/* FIXME: hack for save delta */
	clear_buffer_dirty(buffer);
}

/*
 * Write the MMP block using WRITE_SYNC to try to get the block on-disk
 * faster.
 */
static int write_mmp_block(struct buffer_head *bh)
{
	mark_buffer_dirty(bh);
	lock_buffer(bh);
	bh->b_end_io = end_buffer_write_sync;
	get_bh(bh);
#ifdef FEATURE_STORAGE_META_LOG
	set_metadata_rw_status(bh->b_bdev->bd_disk->first_minor, WAIT_WRITE_CNT);
#endif

	submit_bh(WRITE_SYNC, bh);
	wait_on_buffer(bh);
	if (unlikely(!buffer_uptodate(bh)))
		return 1;

	return 0;
}

/* Warning: even if it returns true, this does *not* guarantee that
 * the block is stored in our inode metadata cache. 
 * 
 * This can be called under lock_buffer()
 */
int ocfs2_buffer_uptodate(struct inode *inode,
			  struct buffer_head *bh)
{
	/* Doesn't matter if the bh is in our cache or not -- if it's
	 * not marked uptodate then we know it can't have correct
	 * data. */
	if (!buffer_uptodate(bh))
		return 0;

	/* OCFS2 does not allow multiple nodes to be changing the same
	 * block at the same time. */
	if (buffer_jbd(bh))
		return 1;

	/* Ok, locally the buffer is marked as up to date, now search
	 * our cache to see if we can trust that. */
	return ocfs2_buffer_cached(OCFS2_I(inode), bh);
}

void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head **bhp)
{
	struct buffer_head *bh;
	/*return hpfs_map_sector(s, secno, bhp, 0);*/

	hpfs_lock_assert(s);

	cond_resched();

	if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
		if (!buffer_uptodate(bh)) wait_on_buffer(bh);
		set_buffer_uptodate(bh);
		return bh->b_data;
	} else {
		pr_err("%s(): getblk failed\n", __func__);
		return NULL;
	}
}

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;
}

static int nilfs_mdt_read_block(struct inode *inode, unsigned long block,
				int readahead, struct buffer_head **out_bh)
{
	struct buffer_head *first_bh, *bh;
	unsigned long blkoff;
	int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS;
	int err;

	err = nilfs_mdt_submit_block(inode, block, READ, &first_bh);
	if (err == -EEXIST) /* internal code */
		goto out;

	if (unlikely(err))
		goto failed;

	if (readahead) {
		blkoff = block + 1;
		for (i = 0; i < nr_ra_blocks; i++, blkoff++) {
			err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh);
			if (likely(!err || err == -EEXIST))
				brelse(bh);
			else if (err != -EBUSY)
				break;
				/* abort readahead if bmap lookup failed */
			if (!buffer_locked(first_bh))
				goto out_no_wait;
		}
	}

	wait_on_buffer(first_bh);

 out_no_wait:
	err = -EIO;
	if (!buffer_uptodate(first_bh))
		goto failed_bh;
 out:
	*out_bh = first_bh;
	return 0;

 failed_bh:
	brelse(first_bh);
 failed:
	return err;
}

/*
 * write back super block information to disk
 *
 * @vsb: the VFS super block structure
 * @wait: whether to wait for the super block to be synced to disk
 *
 * return: 0 on success, error code otherwise
 */
int wtfs_sync_super(struct super_block * vsb, int wait)
{
	struct wtfs_sb_info * sbi = WTFS_SB_INFO(vsb);
	struct wtfs_super_block * sb = NULL;
	struct buffer_head * bh = NULL;
	int ret = -EIO;

	if ((bh = sb_bread(vsb, WTFS_RB_SUPER)) == NULL) {
		wtfs_error("unable to read the super block\n");
		goto error;
	}

	sb = (struct wtfs_super_block *)bh->b_data;
	sb->version = cpu_to_wtfs64(sbi->version);
	sb->magic = cpu_to_wtfs64(sbi->magic);
	sb->block_size = cpu_to_wtfs64(sbi->block_size);
	sb->block_count = cpu_to_wtfs64(sbi->block_count);
	sb->inode_table_first = cpu_to_wtfs64(sbi->inode_table_first);
	sb->inode_table_count = cpu_to_wtfs64(sbi->inode_table_count);
	sb->block_bitmap_first = cpu_to_wtfs64(sbi->block_bitmap_first);
	sb->block_bitmap_count = cpu_to_wtfs64(sbi->block_bitmap_count);
	sb->inode_bitmap_first = cpu_to_wtfs64(sbi->inode_bitmap_first);
	sb->inode_bitmap_count = cpu_to_wtfs64(sbi->inode_bitmap_count);
	sb->inode_count = cpu_to_wtfs64(sbi->inode_count);
	sb->free_block_count = cpu_to_wtfs64(sbi->free_block_count);

	mark_buffer_dirty(bh);
	if (wait) {
		sync_dirty_buffer(bh);
		if (buffer_req(bh) && !buffer_uptodate(bh)) {
			wtfs_error("super block sync failed\n");
			goto error;
		}
	}
	brelse(bh);

	return 0;

error:
	if (bh != NULL) {
		brelse(bh);
	}
	return ret;
}