From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: fuse: convert from readpages to readahead Implement the new readahead operation in fuse by using __readahead_batch() to fill the array of pages in fuse_args_pages directly. This lets us inline fuse_readpages_fill() into fuse_readahead(). [willy@xxxxxxxxxxxxx: build fix] Link: http://lkml.kernel.org/r/20200415025938.GB5820@xxxxxxxxxxxxxxxxxxxxxx Link: http://lkml.kernel.org/r/20200414150233.24495-25-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx> Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx> Acked-by: Miklos Szeredi <mszeredi@xxxxxxxxxx> Cc: Chao Yu <yuchao0@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Cong Wang <xiyou.wangcong@xxxxxxxxx> Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Cc: Eric Biggers <ebiggers@xxxxxxxxxx> Cc: Gao Xiang <gaoxiang25@xxxxxxxxxx> Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Cc: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx> Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Zi Yan <ziy@xxxxxxxxxx> Cc: Johannes Thumshirn <johannes.thumshirn@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/fuse/file.c | 100 +++++++++++++---------------------------------- 1 file changed, 28 insertions(+), 72 deletions(-) --- a/fs/fuse/file.c~fuse-convert-from-readpages-to-readahead +++ a/fs/fuse/file.c @@ -915,84 +915,40 @@ static void fuse_send_readpages(struct f fuse_readpages_end(fc, &ap->args, err); } -struct fuse_fill_data { - struct fuse_io_args *ia; - struct file *file; - struct inode *inode; - unsigned int nr_pages; - unsigned int max_pages; -}; - -static int fuse_readpages_fill(void *_data, struct page *page) +static void fuse_readahead(struct readahead_control *rac) { - struct fuse_fill_data *data = _data; - struct fuse_io_args *ia = data->ia; - struct fuse_args_pages *ap = &ia->ap; - struct inode *inode = data->inode; + struct inode *inode = rac->mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); + unsigned int i, max_pages, nr_pages = 0; - fuse_wait_on_page_writeback(inode, page->index); - - if (ap->num_pages && - (ap->num_pages == fc->max_pages || - (ap->num_pages + 1) * PAGE_SIZE > fc->max_read || - ap->pages[ap->num_pages - 1]->index + 1 != page->index)) { - data->max_pages = min_t(unsigned int, data->nr_pages, - fc->max_pages); - fuse_send_readpages(ia, data->file); - data->ia = ia = fuse_io_alloc(NULL, data->max_pages); - if (!ia) { - unlock_page(page); - return -ENOMEM; - } - ap = &ia->ap; - } - - if (WARN_ON(ap->num_pages >= data->max_pages)) { - unlock_page(page); - fuse_io_free(ia); - return -EIO; - } - - get_page(page); - ap->pages[ap->num_pages] = page; - ap->descs[ap->num_pages].length = PAGE_SIZE; - ap->num_pages++; - data->nr_pages--; - return 0; -} - -static int fuse_readpages(struct file *file, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages) -{ - struct inode *inode = mapping->host; - struct fuse_conn *fc = get_fuse_conn(inode); - struct fuse_fill_data data; - int err; - - err = -EIO; if (is_bad_inode(inode)) - goto out; + return; - data.file = file; - data.inode = inode; - data.nr_pages = nr_pages; - data.max_pages = min_t(unsigned int, nr_pages, fc->max_pages); -; - data.ia = fuse_io_alloc(NULL, data.max_pages); - err = -ENOMEM; - if (!data.ia) - goto out; + max_pages = min_t(unsigned int, fc->max_pages, + fc->max_read / PAGE_SIZE); - err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data); - if (!err) { - if (data.ia->ap.num_pages) - fuse_send_readpages(data.ia, file); - else - fuse_io_free(data.ia); + for (;;) { + struct fuse_io_args *ia; + struct fuse_args_pages *ap; + + nr_pages = readahead_count(rac) - nr_pages; + if (nr_pages > max_pages) + nr_pages = max_pages; + if (nr_pages == 0) + break; + ia = fuse_io_alloc(NULL, nr_pages); + if (!ia) + return; + ap = &ia->ap; + nr_pages = __readahead_batch(rac, ap->pages, nr_pages); + for (i = 0; i < nr_pages; i++) { + fuse_wait_on_page_writeback(inode, + readahead_index(rac) + i); + ap->descs[i].length = PAGE_SIZE; + } + ap->num_pages = nr_pages; + fuse_send_readpages(ia, rac->file); } -out: - return err; } static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to) @@ -3373,10 +3329,10 @@ static const struct file_operations fuse static const struct address_space_operations fuse_file_aops = { .readpage = fuse_readpage, + .readahead = fuse_readahead, .writepage = fuse_writepage, .writepages = fuse_writepages, .launder_page = fuse_launder_page, - .readpages = fuse_readpages, .set_page_dirty = __set_page_dirty_nobuffers, .bmap = fuse_bmap, .direct_IO = fuse_direct_IO, _
