Revert "btrfs: split btrfs_direct_IO to read and write part"

This reverts commit d8f3e735.

The patch is a cleanup of direct IO port to iomap infrastructure,
which gets reverted.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -28,7 +28,6 @@
 #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"
@@ -2935,8 +2934,6 @@ 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_dops;
 
 /* ioctl.c */
 long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);

fs/btrfs/file.c

@@ -1809,61 +1809,21 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
 	return num_written ? num_written : ret;
 }
 
-static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
-                               const struct iov_iter *iter, loff_t offset)
-{
-        const unsigned int 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)
+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);
-	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
-	loff_t pos = iocb->ki_pos;
-	ssize_t written = 0;
+	loff_t pos;
+	ssize_t written;
 	ssize_t written_buffered;
 	loff_t endbyte;
 	int err;
-	size_t count = 0;
-	bool relock = false;
-
-	if (check_direct_IO(fs_info, from, pos))
-		goto buffered;
 
-	count = iov_iter_count(from);
-	/*
-	 * 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 (pos + count <= inode->i_size) {
-		inode_unlock(inode);
-		relock = true;
-	} else if (iocb->ki_flags & IOCB_NOWAIT) {
-		return -EAGAIN;
-	}
-
-	down_read(&BTRFS_I(inode)->dio_sem);
-	written = iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops, &btrfs_dops,
-			       is_sync_kiocb(iocb));
-	up_read(&BTRFS_I(inode)->dio_sem);
-
-	if (relock)
-		inode_lock(inode);
+	written = btrfs_direct_IO(iocb, from);
 
 	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) {
@@ -2002,7 +1962,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 		atomic_inc(&BTRFS_I(inode)->sync_writers);
 
 	if (iocb->ki_flags & IOCB_DIRECT) {
-		num_written = btrfs_direct_write(iocb, from);
+		num_written = __btrfs_direct_write(iocb, from);
 	} else {
 		num_written = btrfs_buffered_write(iocb, from);
 		if (num_written > 0)
@@ -3516,44 +3476,16 @@ static int btrfs_file_open(struct inode *inode, struct file *filp)
 	return generic_file_open(inode, filp);
 }
 
-static int check_direct_read(struct btrfs_fs_info *fs_info,
-                               const struct iov_iter *iter, loff_t offset)
+static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
-	int ret;
-	int i, seg;
-
-	ret = check_direct_IO(fs_info, iter, offset);
-	if (ret < 0)
-		return ret;
-
-	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;
-}
+	ssize_t ret = 0;
 
-static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
-{
+	if (iocb->ki_flags & IOCB_DIRECT) {
 		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 = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dops,
-			   is_sync_kiocb(iocb));
+		ret = btrfs_direct_IO(iocb, to);
 		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)
 			return ret;
 	}

fs/btrfs/inode.c

@@ -29,6 +29,7 @@
 #include <linux/swap.h>
 #include <linux/migrate.h>
 #include <linux/sched/mm.h>
+#include <linux/iomap.h>
 #include <asm/unaligned.h>
 #include "misc.h"
 #include "ctree.h"
@@ -7819,15 +7820,92 @@ static blk_qc_t btrfs_submit_direct(struct inode *inode, struct iomap *iomap,
 	return BLK_QC_T_NONE;
 }
 
-const struct iomap_ops btrfs_dio_iomap_ops = {
+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 const struct iomap_ops btrfs_dio_iomap_ops = {
 	.iomap_begin            = btrfs_dio_iomap_begin,
 	.iomap_end              = btrfs_dio_iomap_end,
 };
 
-const struct iomap_dio_ops btrfs_dops = {
+static const struct iomap_dio_ops btrfs_dops = {
 	.submit_io		= btrfs_submit_direct,
 };
 
+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;
+		} else if (iocb->ki_flags & IOCB_NOWAIT) {
+			ret = -EAGAIN;
+			goto out;
+		}
+		down_read(&BTRFS_I(inode)->dio_sem);
+	}
+
+	ret = iomap_dio_rw(iocb, iter, &btrfs_dio_iomap_ops, &btrfs_dops,
+			is_sync_kiocb(iocb));
+
+	if (iov_iter_rw(iter) == WRITE) {
+		up_read(&BTRFS_I(inode)->dio_sem);
+	}
+out:
+	if (relock)
+		inode_lock(inode);
+	extent_changeset_free(data_reserved);
+	return ret;
+}
+
 #define BTRFS_FIEMAP_FLAGS	(FIEMAP_FLAG_SYNC)
 
 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,