From 925c86a19bacf8ce10eb666328fb3fa5aff7b951 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 1 Aug 2023 19:22:01 +0200 Subject: fs: add CONFIG_BUFFER_HEAD Add a new config option that controls building the buffer_head code, and select it from all file systems and stacking drivers that need it. For the block device nodes and alternative iomap based buffered I/O path is provided when buffer_head support is not enabled, and iomap needs a a small tweak to define the IOMAP_F_BUFFER_HEAD flag to 0 to not call into the buffer_head code when it doesn't exist. Otherwise this is just Kconfig and ifdef changes. Signed-off-by: Christoph Hellwig Reviewed-by: Luis Chamberlain Reviewed-by: Johannes Thumshirn Link: https://lore.kernel.org/r/20230801172201.1923299-7-hch@lst.de Signed-off-by: Jens Axboe --- block/fops.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 60 insertions(+), 10 deletions(-) (limited to 'block/fops.c') diff --git a/block/fops.c b/block/fops.c index 063ece37d44e..eaa98a987213 100644 --- a/block/fops.c +++ b/block/fops.c @@ -24,15 +24,6 @@ static inline struct inode *bdev_file_inode(struct file *file) return file->f_mapping->host; } -static int blkdev_get_block(struct inode *inode, sector_t iblock, - struct buffer_head *bh, int create) -{ - bh->b_bdev = I_BDEV(inode); - bh->b_blocknr = iblock; - set_buffer_mapped(bh); - return 0; -} - static blk_opf_t dio_bio_write_op(struct kiocb *iocb) { blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; @@ -400,7 +391,7 @@ static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length, iomap->type = IOMAP_MAPPED; iomap->addr = iomap->offset; iomap->length = isize - iomap->offset; - iomap->flags |= IOMAP_F_BUFFER_HEAD; + iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */ return 0; } @@ -408,6 +399,16 @@ static const struct iomap_ops blkdev_iomap_ops = { .iomap_begin = blkdev_iomap_begin, }; +#ifdef CONFIG_BUFFER_HEAD +static int blkdev_get_block(struct inode *inode, sector_t iblock, + struct buffer_head *bh, int create) +{ + bh->b_bdev = I_BDEV(inode); + bh->b_blocknr = iblock; + set_buffer_mapped(bh); + return 0; +} + static int blkdev_writepage(struct page *page, struct writeback_control *wbc) { return block_write_full_page(page, blkdev_get_block, wbc); @@ -453,6 +454,55 @@ const struct address_space_operations def_blk_aops = { .migrate_folio = buffer_migrate_folio_norefs, .is_dirty_writeback = buffer_check_dirty_writeback, }; +#else /* CONFIG_BUFFER_HEAD */ +static int blkdev_read_folio(struct file *file, struct folio *folio) +{ + return iomap_read_folio(folio, &blkdev_iomap_ops); +} + +static void blkdev_readahead(struct readahead_control *rac) +{ + iomap_readahead(rac, &blkdev_iomap_ops); +} + +static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc, + struct inode *inode, loff_t offset) +{ + loff_t isize = i_size_read(inode); + + if (WARN_ON_ONCE(offset >= isize)) + return -EIO; + if (offset >= wpc->iomap.offset && + offset < wpc->iomap.offset + wpc->iomap.length) + return 0; + return blkdev_iomap_begin(inode, offset, isize - offset, + IOMAP_WRITE, &wpc->iomap, NULL); +} + +static const struct iomap_writeback_ops blkdev_writeback_ops = { + .map_blocks = blkdev_map_blocks, +}; + +static int blkdev_writepages(struct address_space *mapping, + struct writeback_control *wbc) +{ + struct iomap_writepage_ctx wpc = { }; + + return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops); +} + +const struct address_space_operations def_blk_aops = { + .dirty_folio = filemap_dirty_folio, + .release_folio = iomap_release_folio, + .invalidate_folio = iomap_invalidate_folio, + .read_folio = blkdev_read_folio, + .readahead = blkdev_readahead, + .writepages = blkdev_writepages, + .is_partially_uptodate = iomap_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, + .migrate_folio = filemap_migrate_folio, +}; +#endif /* CONFIG_BUFFER_HEAD */ /* * for a block special file file_inode(file)->i_size is zero -- cgit