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bdev: make struct bdev_handle private to the block layer 

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-29-adbd023e19cc@kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2024-01-23 14:26:46 +01:00
parent b1211a25c4
commit a56aefca8d
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
5 changed files with 86 additions and 95 deletions
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119
block/bdev.c
View File

@ -703,6 +703,24 @@ out_blkdev_put:
return ret;
}
int bdev_permission(dev_t dev, blk_mode_t mode, void *holder)
{
int ret;
ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
MAJOR(dev), MINOR(dev),
((mode & BLK_OPEN_READ) ? DEVCG_ACC_READ : 0) |
((mode & BLK_OPEN_WRITE) ? DEVCG_ACC_WRITE : 0));
if (ret)
return ret;
/* Blocking writes requires exclusive opener */
if (mode & BLK_OPEN_RESTRICT_WRITES && !holder)
return -EINVAL;
return 0;
}
static void blkdev_put_part(struct block_device *part)
{
struct block_device *whole = bdev_whole(part);
@ -795,69 +813,43 @@ static void bdev_yield_write_access(struct block_device *bdev, blk_mode_t mode)
}
/**
* bdev_open_by_dev - open a block device by device number
* @dev: device number of block device to open
* bdev_open - open a block device
* @bdev: block device to open
* @mode: open mode (BLK_OPEN_*)
* @holder: exclusive holder identifier
* @hops: holder operations
* @bdev_file: file for the block device
*
* Open the block device described by device number @dev. If @holder is not
* %NULL, the block device is opened with exclusive access. Exclusive opens may
* nest for the same @holder.
*
* Use this interface ONLY if you really do not have anything better - i.e. when
* you are behind a truly sucky interface and all you are given is a device
* number. Everything else should use bdev_open_by_path().
* Open the block device. If @holder is not %NULL, the block device is opened
* with exclusive access. Exclusive opens may nest for the same @holder.
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* Handle with a reference to the block_device on success, ERR_PTR(-errno) on
* failure.
* zero on success, -errno on failure.
*/
struct bdev_handle *bdev_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
const struct blk_holder_ops *hops)
int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
const struct blk_holder_ops *hops, struct file *bdev_file)
{
struct bdev_handle *handle = kmalloc(sizeof(struct bdev_handle),
GFP_KERNEL);
struct block_device *bdev;
struct bdev_handle *handle;
bool unblock_events = true;
struct gendisk *disk;
struct gendisk *disk = bdev->bd_disk;
int ret;
handle = kmalloc(sizeof(struct bdev_handle), GFP_KERNEL);
if (!handle)
return ERR_PTR(-ENOMEM);
ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
MAJOR(dev), MINOR(dev),
((mode & BLK_OPEN_READ) ? DEVCG_ACC_READ : 0) |
((mode & BLK_OPEN_WRITE) ? DEVCG_ACC_WRITE : 0));
if (ret)
goto free_handle;
/* Blocking writes requires exclusive opener */
if (mode & BLK_OPEN_RESTRICT_WRITES && !holder) {
ret = -EINVAL;
goto free_handle;
}
bdev = blkdev_get_no_open(dev);
if (!bdev) {
ret = -ENXIO;
goto free_handle;
}
disk = bdev->bd_disk;
return -ENOMEM;
if (holder) {
mode |= BLK_OPEN_EXCL;
ret = bd_prepare_to_claim(bdev, holder, hops);
if (ret)
goto put_blkdev;
goto free_handle;
} else {
if (WARN_ON_ONCE(mode & BLK_OPEN_EXCL)) {
ret = -EIO;
goto put_blkdev;
goto free_handle;
}
}
@ -902,7 +894,16 @@ struct bdev_handle *bdev_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
handle->bdev = bdev;
handle->holder = holder;
handle->mode = mode;
return handle;
bdev_file->f_flags |= O_LARGEFILE;
bdev_file->f_mode |= FMODE_BUF_RASYNC | FMODE_CAN_ODIRECT;
if (bdev_nowait(bdev))
bdev_file->f_mode |= FMODE_NOWAIT;
bdev_file->f_mapping = handle->bdev->bd_inode->i_mapping;
bdev_file->f_wb_err = filemap_sample_wb_err(bdev_file->f_mapping);
bdev_file->private_data = handle;
return 0;
put_module:
module_put(disk->fops->owner);
abort_claiming:
@ -910,11 +911,9 @@ abort_claiming:
bd_abort_claiming(bdev, holder);
mutex_unlock(&disk->open_mutex);
disk_unblock_events(disk);
put_blkdev:
blkdev_put_no_open(bdev);
free_handle:
kfree(handle);
return ERR_PTR(ret);
return ret;
}
/*
@ -951,29 +950,33 @@ struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
const struct blk_holder_ops *hops)
{
struct file *bdev_file;
struct bdev_handle *handle;
struct block_device *bdev;
unsigned int flags;
int ret;
handle = bdev_open_by_dev(dev, mode, holder, hops);
if (IS_ERR(handle))
return ERR_CAST(handle);
ret = bdev_permission(dev, mode, holder);
if (ret)
return ERR_PTR(ret);
bdev = blkdev_get_no_open(dev);
if (!bdev)
return ERR_PTR(-ENXIO);
flags = blk_to_file_flags(mode);
bdev_file = alloc_file_pseudo_noaccount(handle->bdev->bd_inode,
bdev_file = alloc_file_pseudo_noaccount(bdev->bd_inode,
blockdev_mnt, "", flags | O_LARGEFILE, &def_blk_fops);
if (IS_ERR(bdev_file)) {
bdev_release(handle);
blkdev_put_no_open(bdev);
return bdev_file;
}
ihold(handle->bdev->bd_inode);
ihold(bdev->bd_inode);
bdev_file->f_mode |= FMODE_BUF_RASYNC | FMODE_CAN_ODIRECT;
if (bdev_nowait(handle->bdev))
bdev_file->f_mode |= FMODE_NOWAIT;
bdev_file->f_mapping = handle->bdev->bd_inode->i_mapping;
bdev_file->f_wb_err = filemap_sample_wb_err(bdev_file->f_mapping);
bdev_file->private_data = handle;
ret = bdev_open(bdev, mode, holder, hops, bdev_file);
if (ret) {
blkdev_put_no_open(bdev);
fput(bdev_file);
return ERR_PTR(ret);
}
return bdev_file;
}
EXPORT_SYMBOL(bdev_file_open_by_dev);

12
block/blk.h
View File

@ -25,6 +25,12 @@ struct blk_flush_queue {
struct request *flush_rq;
};
struct bdev_handle {
struct block_device *bdev;
void *holder;
blk_mode_t mode;
};
bool is_flush_rq(struct request *req);
struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size,
@ -517,7 +523,7 @@ static inline int req_ref_read(struct request *req)
}
void bdev_release(struct bdev_handle *handle);
struct bdev_handle *bdev_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
const struct blk_holder_ops *hops);
int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
const struct blk_holder_ops *hops, struct file *bdev_file);
int bdev_permission(dev_t dev, blk_mode_t mode, void *holder);
#endif /* BLK_INTERNAL_H */

37
block/fops.c
View File

@ -599,36 +599,31 @@ blk_mode_t file_to_blk_mode(struct file *file)
static int blkdev_open(struct inode *inode, struct file *filp)
{
struct bdev_handle *handle;
struct block_device *bdev;
blk_mode_t mode;
/*
* Preserve backwards compatibility and allow large file access
* even if userspace doesn't ask for it explicitly. Some mkfs
* binary needs it. We might want to drop this workaround
* during an unstable branch.
*/
filp->f_flags |= O_LARGEFILE;
filp->f_mode |= FMODE_BUF_RASYNC | FMODE_CAN_ODIRECT;
void *holder;
int ret;
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);
holder = mode & BLK_OPEN_EXCL ? filp : NULL;
ret = bdev_permission(inode->i_rdev, mode, holder);
if (ret)
return ret;
if (bdev_nowait(handle->bdev))
filp->f_mode |= FMODE_NOWAIT;
bdev = blkdev_get_no_open(inode->i_rdev);
if (!bdev)
return -ENXIO;
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;
ret = bdev_open(bdev, mode, holder, NULL, filp);
if (ret)
blkdev_put_no_open(bdev);
return ret;
}
static int blkdev_release(struct inode *inode, struct file *filp)
{
bdev_release(filp->private_data);
if (filp->private_data)
bdev_release(filp->private_data);
return 0;
}

7
include/linux/blkdev.h
View File

@ -1475,13 +1475,6 @@ extern const struct blk_holder_ops fs_holder_ops;
(BLK_OPEN_READ | BLK_OPEN_RESTRICT_WRITES | \
(((flags) & SB_RDONLY) ? 0 : BLK_OPEN_WRITE))
/* @bdev_handle will be removed soon. */
struct bdev_handle {
struct block_device *bdev;
void *holder;
blk_mode_t mode;
};
struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
const struct blk_holder_ops *hops);
struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode,

6
include/linux/fs.h
View File

@ -1327,12 +1327,6 @@ struct super_block {
struct list_head s_inodes_wb; /* writeback inodes */
} __randomize_layout;
/* Temporary helper that will go away. */
static inline struct bdev_handle *sb_bdev_handle(struct super_block *sb)
{
return sb->s_bdev_file->private_data;
}
static inline struct user_namespace *i_user_ns(const struct inode *inode)
{
return inode->i_sb->s_user_ns;