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Currently, block device inodes stay around after corresponding gendisk hash died until memory reclaim finds them and frees them. Since we will make block device inode pin the bdi, we want to free the block device inode as soon as the device goes away so that bdi does not stay around unnecessarily. Furthermore we need to avoid issues when new device with the same major,minor pair gets created since reusing the bdi structure would be rather difficult in this case. Unhashing block device inode on gendisk destruction nicely deals with these problems. Once last block device inode reference is dropped (which may be directly in del_gendisk()), the inode gets evicted. Furthermore if the major,minor pair gets reallocated, we are guaranteed to get new block device inode even if old block device inode is not yet evicted and thus we avoid issues with possible reuse of bdi. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.