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Commit fbe10494 authored by Zheng Liu's avatar Zheng Liu Committed by Theodore Ts'o
Browse files

ext4: split ext4_file_write into buffered IO and direct IO 



ext4_file_dio_write is defined in order to split buffered IO and
direct IO in ext4.  This patch just refactor some stuff in write path.

CC: Tao Ma <tm@tao.ma>
CC: Eric Sandeen <sandeen@redhat.com>
CC: Robin Dong <hao.bigrat@gmail.com>
Signed-off-by: default avatarZheng Liu <wenqing.lz@taobao.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 62a1391d

fs/ext4/file.c

+38 −22
Original line number Diff line number Diff line
@@ -90,34 +90,16 @@ ext4_unaligned_aio(struct inode *inode, const struct iovec *iov, 
}



static ssize_t

ext4_file_write(struct kiocb *iocb, const struct iovec *iov,

ext4_file_dio_write(struct kiocb *iocb, const struct iovec *iov,

		    unsigned long nr_segs, loff_t pos)

{

	struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;

	int unaligned_aio = 0;

	ssize_t ret;



	/*

	 * If we have encountered a bitmap-format file, the size limit

	 * is smaller than s_maxbytes, which is for extent-mapped files.

	 */



	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {

		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);

		size_t length = iov_length(iov, nr_segs);



		if ((pos > sbi->s_bitmap_maxbytes ||

		    (pos == sbi->s_bitmap_maxbytes && length > 0)))

			return -EFBIG;



		if (pos + length > sbi->s_bitmap_maxbytes) {

			nr_segs = iov_shorten((struct iovec *)iov, nr_segs,

					      sbi->s_bitmap_maxbytes - pos);

		}

	} else if (unlikely((iocb->ki_filp->f_flags & O_DIRECT) &&

		   !is_sync_kiocb(iocb))) {

	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&

	    !is_sync_kiocb(iocb))

		unaligned_aio = ext4_unaligned_aio(inode, iov, nr_segs, pos);

	}



	/* Unaligned direct AIO must be serialized; see comment above */

	if (unaligned_aio) {
@@ -141,6 +123,40 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov, 
	return ret;

}



static ssize_t

ext4_file_write(struct kiocb *iocb, const struct iovec *iov,

		unsigned long nr_segs, loff_t pos)

{

	struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;

	ssize_t ret;



	/*

	 * If we have encountered a bitmap-format file, the size limit

	 * is smaller than s_maxbytes, which is for extent-mapped files.

	 */



	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {

		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);

		size_t length = iov_length(iov, nr_segs);



		if ((pos > sbi->s_bitmap_maxbytes ||

		    (pos == sbi->s_bitmap_maxbytes && length > 0)))

			return -EFBIG;



		if (pos + length > sbi->s_bitmap_maxbytes) {

			nr_segs = iov_shorten((struct iovec *)iov, nr_segs,

					      sbi->s_bitmap_maxbytes - pos);

		}

	}



	if (unlikely(iocb->ki_filp->f_flags & O_DIRECT))

		ret = ext4_file_dio_write(iocb, iov, nr_segs, pos);

	else

		ret = generic_file_aio_write(iocb, iov, nr_segs, pos);



	return ret;

}



static const struct vm_operations_struct ext4_file_vm_ops = {

	.fault		= filemap_fault,

	.page_mkwrite   = ext4_page_mkwrite,