Commit 29a5d29e authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues Committed by Jens Axboe
Browse files

xfs: nowait aio support 



If IOCB_NOWAIT is set, bail if the i_rwsem is not lockable
immediately.

IF IOMAP_NOWAIT is set, return EAGAIN in xfs_file_iomap_begin
if it needs allocation either due to file extension, writing to a hole,
or COW or waiting for other DIOs to finish.

Return -EAGAIN if we don't have extent list in memory.

Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 728fbc0e

fs/xfs/xfs_file.c

+26 −6
Original line number Diff line number Diff line
@@ -237,7 +237,11 @@ xfs_file_dax_read( 
	if (!count)

		return 0; /* skip atime */



	if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) {

		if (iocb->ki_flags & IOCB_NOWAIT)

			return -EAGAIN;

		xfs_ilock(ip, XFS_IOLOCK_SHARED);

	}

	ret = dax_iomap_rw(iocb, to, &xfs_iomap_ops);

	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
@@ -541,7 +545,11 @@ xfs_file_dio_aio_write( 
		iolock = XFS_IOLOCK_SHARED;

	}



	if (!xfs_ilock_nowait(ip, iolock)) {

		if (iocb->ki_flags & IOCB_NOWAIT)

			return -EAGAIN;

		xfs_ilock(ip, iolock);

	}



	ret = xfs_file_aio_write_checks(iocb, from, &iolock);

	if (ret)
@@ -553,9 +561,15 @@ xfs_file_dio_aio_write( 
	 * otherwise demote the lock if we had to take the exclusive lock

	 * for other reasons in xfs_file_aio_write_checks.

	 */

	if (unaligned_io)

	if (unaligned_io) {

		/* If we are going to wait for other DIO to finish, bail */

		if (iocb->ki_flags & IOCB_NOWAIT) {

			if (atomic_read(&inode->i_dio_count))

				return -EAGAIN;

		} else {

			inode_dio_wait(inode);

	else if (iolock == XFS_IOLOCK_EXCL) {

		}

	} else if (iolock == XFS_IOLOCK_EXCL) {

		xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);

		iolock = XFS_IOLOCK_SHARED;

	}
@@ -585,7 +599,12 @@ xfs_file_dax_write( 
	size_t			count;

	loff_t			pos;



	if (!xfs_ilock_nowait(ip, iolock)) {

		if (iocb->ki_flags & IOCB_NOWAIT)

			return -EAGAIN;

		xfs_ilock(ip, iolock);

	}



	ret = xfs_file_aio_write_checks(iocb, from, &iolock);

	if (ret)

		goto out;
@@ -892,6 +911,7 @@ xfs_file_open( 
		return -EFBIG;

	if (XFS_FORCED_SHUTDOWN(XFS_M(inode->i_sb)))

		return -EIO;

	file->f_mode |= FMODE_AIO_NOWAIT;

	return 0;

}

fs/xfs/xfs_iomap.c

+22 −0
Original line number Diff line number Diff line
@@ -995,6 +995,11 @@ xfs_file_iomap_begin( 
		lockmode = xfs_ilock_data_map_shared(ip);

	}



	if ((flags & IOMAP_NOWAIT) && !(ip->i_df.if_flags & XFS_IFEXTENTS)) {

		error = -EAGAIN;

		goto out_unlock;

	}



	ASSERT(offset <= mp->m_super->s_maxbytes);

	if ((xfs_fsize_t)offset + length > mp->m_super->s_maxbytes)

		length = mp->m_super->s_maxbytes - offset;
@@ -1016,6 +1021,15 @@ xfs_file_iomap_begin( 


	if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {

		if (flags & IOMAP_DIRECT) {

			/*

			 * A reflinked inode will result in CoW alloc.

			 * FIXME: It could still overwrite on unshared extents

			 * and not need allocation.

			 */

			if (flags & IOMAP_NOWAIT) {

				error = -EAGAIN;

				goto out_unlock;

			}

			/* may drop and re-acquire the ilock */

			error = xfs_reflink_allocate_cow(ip, &imap, &shared,

					&lockmode);
@@ -1032,6 +1046,14 @@ xfs_file_iomap_begin( 
	}



	if ((flags & IOMAP_WRITE) && imap_needs_alloc(inode, &imap, nimaps)) {

		/*

		 * If nowait is set bail since we are going to make

		 * allocations.

		 */

		if (flags & IOMAP_NOWAIT) {

			error = -EAGAIN;

			goto out_unlock;

		}

		/*

		 * We cap the maximum length we map here to MAX_WRITEBACK_PAGES

		 * pages to keep the chunks of work done where somewhat symmetric

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