Commit 14a5275d authored by Joseph Qi's avatar Joseph Qi Committed by Linus Torvalds
Browse files

ocfs2: do not use ocfs2_zero_extend during direct IO 



In ocfs2_direct_IO_write, we use ocfs2_zero_extend to zero allocated
clusters in case of cluster not aligned.  But ocfs2_zero_extend uses page
cache, this may happen that it clears the data which blockdev_direct_IO
has already written.

We should use blkdev_issue_zeroout instead of ocfs2_zero_extend during
direct IO.

So fix this issue by introducing ocfs2_direct_IO_zero_extend and
ocfs2_direct_IO_extend_no_holes.

Reported-by: default avatarYiwen Jiang <jiangyiwen@huawei.com>
Signed-off-by: default avatarJoseph Qi <joseph.qi@huawei.com>
Tested-by: default avatarYiwen Jiang <jiangyiwen@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 37a8d89a

fs/ocfs2/aops.c

+130 −8
Original line number Diff line number Diff line
@@ -663,6 +663,117 @@ static int ocfs2_is_overwrite(struct ocfs2_super *osb, 
	return 0;

}



static int ocfs2_direct_IO_zero_extend(struct ocfs2_super *osb,

		struct inode *inode, loff_t offset,

		u64 zero_len, int cluster_align)

{

	u32 p_cpos = 0;

	u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, i_size_read(inode));

	unsigned int num_clusters = 0;

	unsigned int ext_flags = 0;

	int ret = 0;



	if (offset <= i_size_read(inode) || cluster_align)

		return 0;



	ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos, &num_clusters,

			&ext_flags);

	if (ret < 0) {

		mlog_errno(ret);

		return ret;

	}



	if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) {

		u64 s = i_size_read(inode);

		sector_t sector = (p_cpos << (osb->s_clustersize_bits - 9)) +

			(do_div(s, osb->s_clustersize) >> 9);



		ret = blkdev_issue_zeroout(osb->sb->s_bdev, sector,

				zero_len >> 9, GFP_NOFS, false);

		if (ret < 0)

			mlog_errno(ret);

	}



	return ret;

}



static int ocfs2_direct_IO_extend_no_holes(struct ocfs2_super *osb,

		struct inode *inode, loff_t offset)

{

	u64 zero_start, zero_len, total_zero_len;

	u32 p_cpos = 0, clusters_to_add;

	u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, i_size_read(inode));

	unsigned int num_clusters = 0;

	unsigned int ext_flags = 0;

	u32 size_div, offset_div;

	int ret = 0;



	{

		u64 o = offset;

		u64 s = i_size_read(inode);



		offset_div = do_div(o, osb->s_clustersize);

		size_div = do_div(s, osb->s_clustersize);

	}



	if (offset <= i_size_read(inode))

		return 0;



	clusters_to_add = ocfs2_bytes_to_clusters(inode->i_sb, offset) -

		ocfs2_bytes_to_clusters(inode->i_sb, i_size_read(inode));

	total_zero_len = offset - i_size_read(inode);

	if (clusters_to_add)

		total_zero_len -= offset_div;



	/* Allocate clusters to fill out holes, and this is only needed

	 * when we add more than one clusters. Otherwise the cluster will

	 * be allocated during direct IO */

	if (clusters_to_add > 1) {

		ret = ocfs2_extend_allocation(inode,

				OCFS2_I(inode)->ip_clusters,

				clusters_to_add - 1, 0);

		if (ret) {

			mlog_errno(ret);

			goto out;

		}

	}



	while (total_zero_len) {

		ret = ocfs2_get_clusters(inode, v_cpos, &p_cpos, &num_clusters,

				&ext_flags);

		if (ret < 0) {

			mlog_errno(ret);

			goto out;

		}



		zero_start = ocfs2_clusters_to_bytes(osb->sb, p_cpos) +

			size_div;

		zero_len = ocfs2_clusters_to_bytes(osb->sb, num_clusters) -

			size_div;

		zero_len = min(total_zero_len, zero_len);



		if (p_cpos && !(ext_flags & OCFS2_EXT_UNWRITTEN)) {

			ret = blkdev_issue_zeroout(osb->sb->s_bdev,

					zero_start >> 9, zero_len >> 9,

					GFP_NOFS, false);

			if (ret < 0) {

				mlog_errno(ret);

				goto out;

			}

		}



		total_zero_len -= zero_len;

		v_cpos += ocfs2_bytes_to_clusters(osb->sb, zero_len + size_div);



		/* Only at first iteration can be cluster not aligned.

		 * So set size_div to 0 for the rest */

		size_div = 0;

	}



out:

	return ret;

}



static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb,

		struct iov_iter *iter,

		loff_t offset)
@@ -677,8 +788,8 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, 
	struct buffer_head *di_bh = NULL;

	size_t count = iter->count;

	journal_t *journal = osb->journal->j_journal;

	u32 zero_len;

	int cluster_align;

	u64 zero_len_head, zero_len_tail;

	int cluster_align_head, cluster_align_tail;

	loff_t final_size = offset + count;

	int append_write = offset >= i_size_read(inode) ? 1 : 0;

	unsigned int num_clusters = 0;
@@ -686,9 +797,16 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, 


	{

		u64 o = offset;

		u64 s = i_size_read(inode);



		zero_len = do_div(o, 1 << osb->s_clustersize_bits);

		cluster_align = !zero_len;

		zero_len_head = do_div(o, 1 << osb->s_clustersize_bits);

		cluster_align_head = !zero_len_head;



		zero_len_tail = osb->s_clustersize -

			do_div(s, osb->s_clustersize);

		if ((offset - i_size_read(inode)) < zero_len_tail)

			zero_len_tail = offset - i_size_read(inode);

		cluster_align_tail = !zero_len_tail;

	}



	/*
@@ -712,10 +830,13 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, 
			goto clean_orphan;

		}



		/* zeroing out the previously allocated cluster tail

		 * that but not zeroed */

		if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))

			ret = ocfs2_zero_extend(inode, di_bh, offset);

			ret = ocfs2_direct_IO_zero_extend(osb, inode, offset,

					zero_len_tail, cluster_align_tail);

		else

			ret = ocfs2_extend_no_holes(inode, di_bh, offset,

			ret = ocfs2_direct_IO_extend_no_holes(osb, inode,

					offset);

		if (ret < 0) {

			mlog_errno(ret);
@@ -768,7 +889,8 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, 
				mlog_errno(ret);

		}

	} else if (written > 0 && append_write && !is_overwrite &&

			!cluster_align) {

			!cluster_align_head) {

		/* zeroing out the allocated cluster head */

		u32 p_cpos = 0;

		u32 v_cpos = ocfs2_bytes_to_clusters(osb->sb, offset);
@@ -790,7 +912,7 @@ static ssize_t ocfs2_direct_IO_write(struct kiocb *iocb, 


		ret = blkdev_issue_zeroout(osb->sb->s_bdev,

				p_cpos << (osb->s_clustersize_bits - 9),

				zero_len >> 9, GFP_NOFS, false);

				zero_len_head >> 9, GFP_NOFS, false);

		if (ret < 0)

			mlog_errno(ret);

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