btrfs: split btrfs_direct_IO to read and write

The read and write DIO don't have anything in common except for the
call to iomap_dio_rw. Extract the write call into a new function to get
rid of conditional statements for direct write.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 3 insertions, 88 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 21a354dad6f2..6fd561ac9866 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7954,39 +7954,6 @@ out_err:
 	return BLK_QC_T_NONE;
 }
 
-static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
-			       const struct iov_iter *iter, loff_t offset)
-{
-	int seg;
-	int i;
-	unsigned int blocksize_mask = fs_info->sectorsize - 1;
-	ssize_t retval = -EINVAL;
-
-	if (offset & blocksize_mask)
-		goto out;
-
-	if (iov_iter_alignment(iter) & blocksize_mask)
-		goto out;
-
-	/* If this is a write we don't need to check anymore */
-	if (iov_iter_rw(iter) != READ || !iter_is_iovec(iter))
-		return 0;
-	/*
-	 * Check to make sure we don't have duplicate iov_base's in this
-	 * iovec, if so return EINVAL, otherwise we'll get csum errors
-	 * when reading back.
-	 */
-	for (seg = 0; seg < iter->nr_segs; seg++) {
-		for (i = seg + 1; i < iter->nr_segs; i++) {
-			if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
-				goto out;
-		}
-	}
-	retval = 0;
-out:
-	return retval;
-}
-
 static inline int btrfs_maybe_fsync_end_io(struct kiocb *iocb, ssize_t size,
 					   int error, unsigned flags)
 {
@@ -8011,72 +7978,20 @@ static inline int btrfs_maybe_fsync_end_io(struct kiocb *iocb, ssize_t size,
 	return 0;
 }
 
-static const struct iomap_ops btrfs_dio_iomap_ops = {
+const struct iomap_ops btrfs_dio_iomap_ops = {
 	.iomap_begin            = btrfs_dio_iomap_begin,
 	.iomap_end              = btrfs_dio_iomap_end,
 };
 
-static const struct iomap_dio_ops btrfs_dio_ops = {
+const struct iomap_dio_ops btrfs_dio_ops = {
 	.submit_io		= btrfs_submit_direct,
 };
 
-static const struct iomap_dio_ops btrfs_sync_dops = {
+const struct iomap_dio_ops btrfs_sync_dops = {
 	.submit_io		= btrfs_submit_direct,
 	.end_io			= btrfs_maybe_fsync_end_io,
 };
 
-ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
-{
-	struct file *file = iocb->ki_filp;
-	struct inode *inode = file->f_mapping->host;
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
-	struct extent_changeset *data_reserved = NULL;
-	loff_t offset = iocb->ki_pos;
-	size_t count = 0;
-	bool relock = false;
-	ssize_t ret;
-
-	if (check_direct_IO(fs_info, iter, offset))
-		return 0;
-
-	count = iov_iter_count(iter);
-	if (iov_iter_rw(iter) == WRITE) {
-		/*
-		 * If the write DIO is beyond the EOF, we need update
-		 * the isize, but it is protected by i_mutex. So we can
-		 * not unlock the i_mutex at this case.
-		 */
-		if (offset + count <= inode->i_size) {
-			inode_unlock(inode);
-			relock = true;
-		}
-		down_read(&BTRFS_I(inode)->dio_sem);
-	}
-
-	/*
-	 * We have are actually a sync iocb, so we need our fancy endio to know
-	 * if we need to sync.
-	 */
-	if (current->journal_info)
-		ret = iomap_dio_rw(iocb, iter, &btrfs_dio_iomap_ops,
-				   &btrfs_sync_dops, is_sync_kiocb(iocb));
-	else
-		ret = iomap_dio_rw(iocb, iter, &btrfs_dio_iomap_ops,
-				   &btrfs_dio_ops, is_sync_kiocb(iocb));
-
-	if (ret == -ENOTBLK)
-		ret = 0;
-
-	if (iov_iter_rw(iter) == WRITE)
-		up_read(&BTRFS_I(inode)->dio_sem);
-
-	if (relock)
-		inode_lock(inode);
-
-	extent_changeset_free(data_reserved);
-	return ret;
-}
-
 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 			u64 start, u64 len)
 {