Commit 4e4cabec authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues Committed by David Sterba
Browse files

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: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 3d8cc17a

fs/btrfs/ctree.h

+4 −1
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/dynamic_debug.h>

#include <linux/refcount.h>

#include <linux/crc32c.h>

#include <linux/iomap.h>

#include "extent-io-tree.h"

#include "extent_io.h"

#include "extent_map.h"
@@ -3065,7 +3066,9 @@ int btrfs_writepage_cow_fixup(struct page *page, u64 start, u64 end); 
void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start,

					  u64 end, int uptodate);

extern const struct dentry_operations btrfs_dentry_operations;

ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter);

extern const struct iomap_ops btrfs_dio_iomap_ops;

extern const struct iomap_dio_ops btrfs_dio_ops;

extern const struct iomap_dio_ops btrfs_sync_dops;



/* ioctl.c */

long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);

fs/btrfs/file.c

+87 −10
Original line number Diff line number Diff line
@@ -1782,21 +1782,67 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb, 
	return num_written ? num_written : ret;

}



static ssize_t __btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)

static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,

			       const struct iov_iter *iter, loff_t offset)

{

	const u32 blocksize_mask = fs_info->sectorsize - 1;



	if (offset & blocksize_mask)

		return -EINVAL;



	if (iov_iter_alignment(iter) & blocksize_mask)

		return -EINVAL;



	return 0;

}



static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)

{

	struct file *file = iocb->ki_filp;

	struct inode *inode = file_inode(file);

	loff_t pos;

	ssize_t written;

	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);

	loff_t pos = iocb->ki_pos;

	ssize_t written = 0;

	bool relock = false;

	ssize_t written_buffered;

	loff_t endbyte;

	int err;



	written = btrfs_direct_IO(iocb, from);

	if (check_direct_IO(fs_info, from, pos))

		goto buffered;



	/*

	 * If the write DIO is beyond EOF, we need to update the isize, but it

	 * is protected by inode lock. So we cannot unlock it here.

	 */

	if (pos + iov_iter_count(from) <= inode->i_size) {

		inode_unlock(inode);

		relock = true;

	}

	down_read(&BTRFS_I(inode)->dio_sem);



	/*

	 * This is actually a sync iocb, so we need our fancy endio to know if

	 * we need to sync.

	 */

	if (current->journal_info)

		written = iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops,

				       &btrfs_sync_dops, is_sync_kiocb(iocb));

	else

		written = iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops,

				       &btrfs_dio_ops, is_sync_kiocb(iocb));



	if (written == -ENOTBLK)

		written = 0;



	up_read(&BTRFS_I(inode)->dio_sem);

	if (relock)

		inode_lock(inode);



	if (written < 0 || !iov_iter_count(from))

		return written;



buffered:

	pos = iocb->ki_pos;

	written_buffered = btrfs_buffered_write(iocb, from);

	if (written_buffered < 0) {
@@ -1970,7 +2016,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, 
			iocb->ki_flags &= ~IOCB_DSYNC;

			current->journal_info = BTRFS_DIO_SYNC_STUB;

		}

		num_written = __btrfs_direct_write(iocb, from);

		num_written = btrfs_direct_write(iocb, from);



		/*

		 * As stated above, we cleared journal_info, so we need to do
@@ -3545,16 +3591,47 @@ static int btrfs_file_open(struct inode *inode, struct file *filp) 
	return generic_file_open(inode, filp);

}



static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)

static int check_direct_read(struct btrfs_fs_info *fs_info,

			     const struct iov_iter *iter, loff_t offset)

{

	ssize_t ret = 0;

	int ret;

	int i, seg;



	if (iocb->ki_flags & IOCB_DIRECT) {

	ret = check_direct_IO(fs_info, iter, offset);

	if (ret < 0)

		return ret;



	if (!iter_is_iovec(iter))

		return 0;



	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)

				return -EINVAL;

	return 0;

}



static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)

{

	struct inode *inode = file_inode(iocb->ki_filp);

	ssize_t ret;



	if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))

		return 0;



	inode_lock_shared(inode);

		ret = btrfs_direct_IO(iocb, to);

	ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops,

			   is_sync_kiocb(iocb));

	inode_unlock_shared(inode);

	return ret;

}



static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)

{

	ssize_t ret = 0;



	if (iocb->ki_flags & IOCB_DIRECT) {

		ret = btrfs_direct_read(iocb, to);

		if (ret < 0 || !iov_iter_count(to) ||

		    iocb->ki_pos >= i_size_read(file_inode(iocb->ki_filp)))

			return ret;

fs/btrfs/inode.c

+3 −88
Original line number Diff line number Diff line
@@ -7954,39 +7954,6 @@ static blk_qc_t btrfs_submit_direct(struct inode *inode, struct iomap *iomap, 
	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)

{