forked from mirrors/linux
		
	block: use iomap for writes to block devices
Use iomap in buffer_head compat mode to write to block devices. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Pankaj Raghav <p.raghav@samsung.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Christian Brauner <brauner@kernel.org> Link: https://lore.kernel.org/r/20230801172201.1923299-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
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					 2 changed files with 30 additions and 2 deletions
				
			
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			@ -5,6 +5,7 @@
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menuconfig BLOCK
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       bool "Enable the block layer" if EXPERT
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       default y
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       select FS_IOMAP
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       select SBITMAP
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       help
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	 Provide block layer support for the kernel.
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										31
									
								
								block/fops.c
									
									
									
									
									
								
							
							
						
						
									
										31
									
								
								block/fops.c
									
									
									
									
									
								
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			@ -15,6 +15,7 @@
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#include <linux/falloc.h>
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#include <linux/suspend.h>
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#include <linux/fs.h>
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#include <linux/iomap.h>
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#include <linux/module.h>
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#include "blk.h"
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			@ -386,6 +387,27 @@ static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
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	return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages));
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}
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static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
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		unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
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{
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	struct block_device *bdev = I_BDEV(inode);
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	loff_t isize = i_size_read(inode);
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	iomap->bdev = bdev;
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	iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
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	if (iomap->offset >= isize)
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		return -EIO;
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	iomap->type = IOMAP_MAPPED;
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	iomap->addr = iomap->offset;
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	iomap->length = isize - iomap->offset;
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	iomap->flags |= IOMAP_F_BUFFER_HEAD;
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	return 0;
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}
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static const struct iomap_ops blkdev_iomap_ops = {
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	.iomap_begin		= blkdev_iomap_begin,
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};
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static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
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{
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	return block_write_full_page(page, blkdev_get_block, wbc);
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			@ -556,6 +578,11 @@ blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
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	return written;
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}
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static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
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{
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	return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops);
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}
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/*
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 * Write data to the block device.  Only intended for the block device itself
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 * and the raw driver which basically is a fake block device.
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			@ -605,9 +632,9 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
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		ret = blkdev_direct_write(iocb, from);
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		if (ret >= 0 && iov_iter_count(from))
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			ret = direct_write_fallback(iocb, from, ret,
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					generic_perform_write(iocb, from));
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					blkdev_buffered_write(iocb, from));
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	} else {
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		ret = generic_perform_write(iocb, from);
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		ret = blkdev_buffered_write(iocb, from);
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	}
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	if (ret > 0)
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