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block: Use bdev_open_by_dev() in blkdev_open()

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Convert blkdev_open() to use bdev_open_by_dev(). To be able to propagate
handle from blkdev_open() to blkdev_release() we need to stop using
existence of file->private_data to determine exclusive block device
opens. Use bdev_handle->mode for this purpose since file->f_flags
isn't usable for this (O_EXCL is cleared from the flags during open).

Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-2-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Jan Kara 2023-09-27 11:34:08 +02:00 committed by Christian Brauner
parent e719b4d156
commit 841dd789b8
No known key found for this signature in database
GPG key ID: 91C61BC06578DCA2
3 changed files with 32 additions and 16 deletions
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3
block/bdev.c
View file

@ -844,6 +844,9 @@ struct bdev_handle *bdev_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
}
handle->bdev = bdev;
handle->holder = holder;
if (holder)
mode |= BLK_OPEN_EXCL;
handle->mode = mode;
return handle;
}
EXPORT_SYMBOL(bdev_open_by_dev);

44
block/fops.c
View file

@ -542,15 +542,31 @@ static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
return error;
}
/**
* file_to_blk_mode - get block open flags from file flags
* @file: file whose open flags should be converted
*
* Look at file open flags and generate corresponding block open flags from
* them. The function works both for file just being open (e.g. during ->open
* callback) and for file that is already open. This is actually non-trivial
* (see comment in the function).
*/
blk_mode_t file_to_blk_mode(struct file *file)
{
blk_mode_t mode = 0;
struct bdev_handle *handle = file->private_data;
if (file->f_mode & FMODE_READ)
mode |= BLK_OPEN_READ;
if (file->f_mode & FMODE_WRITE)
mode |= BLK_OPEN_WRITE;
if (file->private_data)
/*
* do_dentry_open() clears O_EXCL from f_flags, use handle->mode to
* determine whether the open was exclusive for already open files.
*/
if (handle)
mode |= handle->mode & BLK_OPEN_EXCL;
else if (file->f_flags & O_EXCL)
mode |= BLK_OPEN_EXCL;
if (file->f_flags & O_NDELAY)
mode |= BLK_OPEN_NDELAY;
@ -568,7 +584,8 @@ blk_mode_t file_to_blk_mode(struct file *file)
static int blkdev_open(struct inode *inode, struct file *filp)
{
struct block_device *bdev;
struct bdev_handle *handle;
blk_mode_t mode;
/*
* Preserve backwards compatibility and allow large file access
@ -579,29 +596,24 @@ static int blkdev_open(struct inode *inode, struct file *filp)
filp->f_flags |= O_LARGEFILE;
filp->f_mode |= FMODE_BUF_RASYNC | FMODE_CAN_ODIRECT;
/*
* Use the file private data to store the holder for exclusive openes.
* file_to_blk_mode relies on it being present to set BLK_OPEN_EXCL.
*/
if (filp->f_flags & O_EXCL)
filp->private_data = filp;
mode = file_to_blk_mode(filp);
handle = bdev_open_by_dev(inode->i_rdev, mode,
mode & BLK_OPEN_EXCL ? filp : NULL, NULL);
if (IS_ERR(handle))
return PTR_ERR(handle);
bdev = blkdev_get_by_dev(inode->i_rdev, file_to_blk_mode(filp),
filp->private_data, NULL);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
if (bdev_nowait(bdev))
if (bdev_nowait(handle->bdev))
filp->f_mode |= FMODE_NOWAIT;
filp->f_mapping = bdev->bd_inode->i_mapping;
filp->f_mapping = handle->bdev->bd_inode->i_mapping;
filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
filp->private_data = handle;
return 0;
}
static int blkdev_release(struct inode *inode, struct file *filp)
{
blkdev_put(I_BDEV(filp->f_mapping->host), filp->private_data);
bdev_release(filp->private_data);
return 0;
}

1
include/linux/blkdev.h
View file

@ -1482,6 +1482,7 @@ extern const struct blk_holder_ops fs_holder_ops;
struct bdev_handle {
struct block_device *bdev;
void *holder;
blk_mode_t mode;
};
struct block_device *blkdev_get_by_dev(dev_t dev, blk_mode_t mode, void *holder,