diff mbox series

[3/6] block: open code __generic_file_write_iter for blkdev writes

Message ID 20230801172201.1923299-4-hch@lst.de (mailing list archive)
State New, archived
Headers show
Series [1/6] fs: remove emergency_thaw_bdev | expand

Commit Message

Christoph Hellwig Aug. 1, 2023, 5:21 p.m. UTC
Open code __generic_file_write_iter to remove the indirect call into
->direct_IO and to prepare using the iomap based write code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/fops.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

Comments

Hannes Reinecke Aug. 1, 2023, 5:48 p.m. UTC | #1
On 8/1/23 19:21, Christoph Hellwig wrote:
> Open code __generic_file_write_iter to remove the indirect call into
> ->direct_IO and to prepare using the iomap based write code.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/fops.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
>   1 file changed, 43 insertions(+), 2 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
Luis Chamberlain Aug. 1, 2023, 6:11 p.m. UTC | #2
On Tue, Aug 01, 2023 at 07:21:58PM +0200, Christoph Hellwig wrote:
> Open code __generic_file_write_iter to remove the indirect call into
> ->direct_IO and to prepare using the iomap based write code.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>

  Luis
Christian Brauner Aug. 2, 2023, 7:26 a.m. UTC | #3
On Tue, Aug 01, 2023 at 07:21:58PM +0200, Christoph Hellwig wrote:
> Open code __generic_file_write_iter to remove the indirect call into
> ->direct_IO and to prepare using the iomap based write code.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Reviewed-by: Christian Brauner <brauner@kernel.org>
Johannes Thumshirn Aug. 2, 2023, 10:06 a.m. UTC | #4
Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Al Viro Aug. 29, 2023, 2:06 a.m. UTC | #5
On Tue, Aug 01, 2023 at 07:21:58PM +0200, Christoph Hellwig wrote:
> @@ -569,7 +594,23 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
>  		iov_iter_truncate(from, size);
>  	}
>  
> -	ret = __generic_file_write_iter(iocb, from);
> +	ret = file_remove_privs(file);
> +	if (ret)
> +		return ret;

That chunk is a bit of a WTF generator...  Thankfully,

static int __file_remove_privs(struct file *file, unsigned int flags)
{
        struct dentry *dentry = file_dentry(file);
	struct inode *inode = file_inode(file);
	int error = 0;
	int kill;

	if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode))
		return 0;

means that it's really a no-op.  But I'd still suggest
removing it, just to reduce the amount of head-scratching
for people who'll be reading that code later...
Christoph Hellwig Aug. 29, 2023, 1:03 p.m. UTC | #6
On Tue, Aug 29, 2023 at 03:06:14AM +0100, Al Viro wrote:
> On Tue, Aug 01, 2023 at 07:21:58PM +0200, Christoph Hellwig wrote:
> > @@ -569,7 +594,23 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
> >  		iov_iter_truncate(from, size);
> >  	}
> >  
> > -	ret = __generic_file_write_iter(iocb, from);
> > +	ret = file_remove_privs(file);
> > +	if (ret)
> > +		return ret;
> 
> That chunk is a bit of a WTF generator...  Thankfully,
> 
> static int __file_remove_privs(struct file *file, unsigned int flags)
> {
>         struct dentry *dentry = file_dentry(file);
> 	struct inode *inode = file_inode(file);
> 	int error = 0;
> 	int kill;
> 
> 	if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode))
> 		return 0;
> 
> means that it's really a no-op.  But I'd still suggest
> removing it, just to reduce the amount of head-scratching
> for people who'll be reading that code later...

I'll send an incremental patch to remove it once the changes hit
Linus' tree.
diff mbox series

Patch

diff --git a/block/fops.c b/block/fops.c
index a286bf3325c5d8..8a05d99166e3bd 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -533,6 +533,30 @@  static int blkdev_release(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+static ssize_t
+blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
+{
+	size_t count = iov_iter_count(from);
+	ssize_t written;
+
+	written = kiocb_invalidate_pages(iocb, count);
+	if (written) {
+		if (written == -EBUSY)
+			return 0;
+		return written;
+	}
+
+	written = blkdev_direct_IO(iocb, from);
+	if (written > 0) {
+		kiocb_invalidate_post_direct_write(iocb, count);
+		iocb->ki_pos += written;
+		count -= written;
+	}
+	if (written != -EIOCBQUEUED)
+		iov_iter_revert(from, count - iov_iter_count(from));
+	return written;
+}
+
 /*
  * Write data to the block device.  Only intended for the block device itself
  * and the raw driver which basically is a fake block device.
@@ -542,7 +566,8 @@  static int blkdev_release(struct inode *inode, struct file *filp)
  */
 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
-	struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
+	struct file *file = iocb->ki_filp;
+	struct block_device *bdev = I_BDEV(file->f_mapping->host);
 	struct inode *bd_inode = bdev->bd_inode;
 	loff_t size = bdev_nr_bytes(bdev);
 	size_t shorted = 0;
@@ -569,7 +594,23 @@  static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		iov_iter_truncate(from, size);
 	}
 
-	ret = __generic_file_write_iter(iocb, from);
+	ret = file_remove_privs(file);
+	if (ret)
+		return ret;
+
+	ret = file_update_time(file);
+	if (ret)
+		return ret;
+
+	if (iocb->ki_flags & IOCB_DIRECT) {
+		ret = blkdev_direct_write(iocb, from);
+		if (ret >= 0 && iov_iter_count(from))
+			ret = direct_write_fallback(iocb, from, ret,
+					generic_perform_write(iocb, from));
+	} else {
+		ret = generic_perform_write(iocb, from);
+	}
+
 	if (ret > 0)
 		ret = generic_write_sync(iocb, ret);
 	iov_iter_reexpand(from, iov_iter_count(from) + shorted);