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Commit a9ab5e84 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Trond Myklebust
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nfs: page cache invalidation for dio 



Make sure to properly invalidate the pagecache before performing direct I/O,
so that no stale pages are left around.  This matches what the generic
direct I/O code does.  Also take the i_mutex over the direct write submission
to avoid the lifelock vs truncate waiting for i_dio_count to decrease, and
to avoid having the pagecache easily repopulated while direct I/O is in
progrss.  Again matching the generic direct I/O code.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent d0b9875d

fs/nfs/direct.c

+27 −2
Original line number Diff line number Diff line
@@ -939,9 +939,12 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, 
	struct inode *inode = mapping->host;

	struct nfs_direct_req *dreq;

	struct nfs_lock_context *l_ctx;

	loff_t end;

	size_t count;



	count = iov_length(iov, nr_segs);

	end = (pos + count - 1) >> PAGE_CACHE_SHIFT;



	nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count);



	dfprintk(FILE, "NFS: direct write(%pD2, %zd@%Ld)\n",
@@ -958,16 +961,25 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, 
	if (!count)

		goto out;



	mutex_lock(&inode->i_mutex);



	result = nfs_sync_mapping(mapping);

	if (result)

		goto out;

		goto out_unlock;



	if (mapping->nrpages) {

		result = invalidate_inode_pages2_range(mapping,

					pos >> PAGE_CACHE_SHIFT, end);

		if (result)

			goto out_unlock;

	}



	task_io_account_write(count);



	result = -ENOMEM;

	dreq = nfs_direct_req_alloc();

	if (!dreq)

		goto out;

		goto out_unlock;



	dreq->inode = inode;

	dreq->bytes_left = count;
@@ -982,6 +994,14 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, 
		dreq->iocb = iocb;



	result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos, uio);



	if (mapping->nrpages) {

		invalidate_inode_pages2_range(mapping,

					      pos >> PAGE_CACHE_SHIFT, end);

	}



	mutex_unlock(&inode->i_mutex);



	if (!result) {

		result = nfs_direct_wait(dreq);

		if (result > 0) {
@@ -994,8 +1014,13 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, 
			spin_unlock(&inode->i_lock);

		}

	}

	nfs_direct_req_release(dreq);

	return result;



out_release:

	nfs_direct_req_release(dreq);

out_unlock:

	mutex_unlock(&inode->i_mutex);

out:

	return result;

}