diff mbox series

[30/31] block: store the holder in file->private_data

Message ID 20230606073950.225178-31-hch@lst.de
State Superseded
Headers show
Series [01/31] block: also call ->open for incremental partition opens | expand

Commit Message

Christoph Hellwig June 6, 2023, 7:39 a.m. UTC
Store the file struct used as the holder in file->private_data as an
indicator that this file descriptor was opened exclusively to  remove
the last use of FMODE_EXCL.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/fops.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

Comments

Christian Brauner June 7, 2023, 9:24 a.m. UTC | #1
On Tue, Jun 06, 2023 at 09:39:49AM +0200, Christoph Hellwig wrote:
> Store the file struct used as the holder in file->private_data as an
> indicator that this file descriptor was opened exclusively to  remove
> the last use of FMODE_EXCL.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Feels a bit odd to store the object itself but anyway,
Acked-by: Christian Brauner <brauner@kernel.org>
Christoph Hellwig June 7, 2023, 12:18 p.m. UTC | #2
On Wed, Jun 07, 2023 at 11:24:55AM +0200, Christian Brauner wrote:
> On Tue, Jun 06, 2023 at 09:39:49AM +0200, Christoph Hellwig wrote:
> > Store the file struct used as the holder in file->private_data as an
> > indicator that this file descriptor was opened exclusively to  remove
> > the last use of FMODE_EXCL.
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > ---
> 
> Feels a bit odd to store the object itself but anyway,
> Acked-by: Christian Brauner <brauner@kernel.org>

We could literally store anything we want.  The only reason I picked the
file is because: a) we have it around and b) that allows passing it
to blkdev_put without a branch in blkdev_release.

If you prefer something else I can change it.
Hannes Reinecke June 7, 2023, 1:14 p.m. UTC | #3
On 6/6/23 09:39, Christoph Hellwig wrote:
> Store the file struct used as the holder in file->private_data as an
> indicator that this file descriptor was opened exclusively to  remove
> the last use of FMODE_EXCL.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/fops.c | 14 ++++++++------
>   1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/block/fops.c b/block/fops.c
> index c40b9f978e3bc7..915e0ef7560993 100644
> --- a/block/fops.c
> +++ b/block/fops.c
> @@ -478,7 +478,7 @@ blk_mode_t file_to_blk_mode(struct file *file)
>   		mode |= BLK_OPEN_READ;
>   	if (file->f_mode & FMODE_WRITE)
>   		mode |= BLK_OPEN_WRITE;
> -	if (file->f_mode & FMODE_EXCL)
> +	if (file->private_data)
>   		mode |= BLK_OPEN_EXCL;
>   	if ((file->f_flags & O_ACCMODE) == 3)
>   		mode |= BLK_OPEN_WRITE_IOCTL;
> @@ -501,12 +501,15 @@ static int blkdev_open(struct inode *inode, struct file *filp)
>   	filp->f_flags |= O_LARGEFILE;
>   	filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
>   
> +	/*
> +	 * Use the file private data to store the holder, file_to_blk_mode
> +	 * relies on this.
> +	 */

Can you update the comment to reflect that we're only use the
->private_data field for exclusive open?
I know it's indicated by the condition, but we really should
be clarify this usage.

>   	if (filp->f_flags & O_EXCL)
> -		filp->f_mode |= FMODE_EXCL;
> +		filp->private_data = filp;
>   
>   	bdev = blkdev_get_by_dev(inode->i_rdev, file_to_blk_mode(filp),
> -				 (filp->f_mode & FMODE_EXCL) ? filp : NULL,
> -				 NULL);
> +				 filp->private_data, NULL);
>   	if (IS_ERR(bdev))
>   		return PTR_ERR(bdev);
>   
> @@ -517,8 +520,7 @@ static int blkdev_open(struct inode *inode, struct file *filp)
>   
>   static int blkdev_release(struct inode *inode, struct file *filp)
>   {
> -	blkdev_put(I_BDEV(filp->f_mapping->host),
> -		   (filp->f_mode & FMODE_EXCL) ? filp : NULL);
> +	blkdev_put(I_BDEV(filp->f_mapping->host), filp->private_data);
>   	return 0;
>   }
>   
Other than that:

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
diff mbox series

Patch

diff --git a/block/fops.c b/block/fops.c
index c40b9f978e3bc7..915e0ef7560993 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -478,7 +478,7 @@  blk_mode_t file_to_blk_mode(struct file *file)
 		mode |= BLK_OPEN_READ;
 	if (file->f_mode & FMODE_WRITE)
 		mode |= BLK_OPEN_WRITE;
-	if (file->f_mode & FMODE_EXCL)
+	if (file->private_data)
 		mode |= BLK_OPEN_EXCL;
 	if ((file->f_flags & O_ACCMODE) == 3)
 		mode |= BLK_OPEN_WRITE_IOCTL;
@@ -501,12 +501,15 @@  static int blkdev_open(struct inode *inode, struct file *filp)
 	filp->f_flags |= O_LARGEFILE;
 	filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
 
+	/*
+	 * Use the file private data to store the holder, file_to_blk_mode
+	 * relies on this.
+	 */
 	if (filp->f_flags & O_EXCL)
-		filp->f_mode |= FMODE_EXCL;
+		filp->private_data = filp;
 
 	bdev = blkdev_get_by_dev(inode->i_rdev, file_to_blk_mode(filp),
-				 (filp->f_mode & FMODE_EXCL) ? filp : NULL,
-				 NULL);
+				 filp->private_data, NULL);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
 
@@ -517,8 +520,7 @@  static int blkdev_open(struct inode *inode, struct file *filp)
 
 static int blkdev_release(struct inode *inode, struct file *filp)
 {
-	blkdev_put(I_BDEV(filp->f_mapping->host),
-		   (filp->f_mode & FMODE_EXCL) ? filp : NULL);
+	blkdev_put(I_BDEV(filp->f_mapping->host), filp->private_data);
 	return 0;
 }