diff options
Diffstat (limited to 'block/bdev.c')
| -rw-r--r-- | block/bdev.c | 101 |
1 files changed, 97 insertions, 4 deletions
diff --git a/block/bdev.c b/block/bdev.c index e9f1b12bd75c..e1149652c532 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -49,6 +49,13 @@ struct block_device *I_BDEV(struct inode *inode) } EXPORT_SYMBOL(I_BDEV); +struct block_device *file_bdev(struct file *bdev_file) +{ + struct bdev_handle *handle = bdev_file->private_data; + return handle->bdev; +} +EXPORT_SYMBOL(file_bdev); + static void bdev_write_inode(struct block_device *bdev) { struct inode *inode = bdev->bd_inode; @@ -368,12 +375,12 @@ static struct file_system_type bd_type = { }; struct super_block *blockdev_superblock __ro_after_init; +struct vfsmount *blockdev_mnt __ro_after_init; EXPORT_SYMBOL_GPL(blockdev_superblock); void __init bdev_cache_init(void) { int err; - static struct vfsmount *bd_mnt __ro_after_init; bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode), 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| @@ -382,10 +389,10 @@ void __init bdev_cache_init(void) err = register_filesystem(&bd_type); if (err) panic("Cannot register bdev pseudo-fs"); - bd_mnt = kern_mount(&bd_type); - if (IS_ERR(bd_mnt)) + blockdev_mnt = kern_mount(&bd_type); + if (IS_ERR(blockdev_mnt)) panic("Cannot create bdev pseudo-fs"); - blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */ + blockdev_superblock = blockdev_mnt->mnt_sb; /* For writeback */ } struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) @@ -911,6 +918,92 @@ free_handle: } EXPORT_SYMBOL(bdev_open_by_dev); +/* + * If BLK_OPEN_WRITE_IOCTL is set then this is a historical quirk + * associated with the floppy driver where it has allowed ioctls if the + * file was opened for writing, but does not allow reads or writes. + * Make sure that this quirk is reflected in @f_flags. + * + * It can also happen if a block device is opened as O_RDWR | O_WRONLY. + */ +static unsigned blk_to_file_flags(blk_mode_t mode) +{ + unsigned int flags = 0; + + if ((mode & (BLK_OPEN_READ | BLK_OPEN_WRITE)) == + (BLK_OPEN_READ | BLK_OPEN_WRITE)) + flags |= O_RDWR; + else if (mode & BLK_OPEN_WRITE_IOCTL) + flags |= O_RDWR | O_WRONLY; + else if (mode & BLK_OPEN_WRITE) + flags |= O_WRONLY; + else if (mode & BLK_OPEN_READ) + flags |= O_RDONLY; /* homeopathic, because O_RDONLY is 0 */ + else + WARN_ON_ONCE(true); + + if (mode & BLK_OPEN_NDELAY) + flags |= O_NDELAY; + + return flags; +} + +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; + unsigned int flags; + + handle = bdev_open_by_dev(dev, mode, holder, hops); + if (IS_ERR(handle)) + return ERR_CAST(handle); + + flags = blk_to_file_flags(mode); + bdev_file = alloc_file_pseudo_noaccount(handle->bdev->bd_inode, + blockdev_mnt, "", flags | O_LARGEFILE, &def_blk_fops); + if (IS_ERR(bdev_file)) { + bdev_release(handle); + return bdev_file; + } + ihold(handle->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; + return bdev_file; +} +EXPORT_SYMBOL(bdev_file_open_by_dev); + +struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode, + void *holder, + const struct blk_holder_ops *hops) +{ + struct file *bdev_file; + dev_t dev; + int error; + + error = lookup_bdev(path, &dev); + if (error) + return ERR_PTR(error); + + bdev_file = bdev_file_open_by_dev(dev, mode, holder, hops); + if (!IS_ERR(bdev_file) && (mode & BLK_OPEN_WRITE)) { + struct bdev_handle *handle = bdev_file->private_data; + if (bdev_read_only(handle->bdev)) { + fput(bdev_file); + bdev_file = ERR_PTR(-EACCES); + } + } + + return bdev_file; +} +EXPORT_SYMBOL(bdev_file_open_by_path); + /** * bdev_open_by_path - open a block device by name * @path: path to the block device to open |