From 8a78cb1f1b98e5ea970674e0f049832d19e76ace Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 1 Jun 2018 09:04:40 -0700 Subject: fs: move page_cache_seek_hole_data to iomap.c This function is only used by the iomap code, depends on being called from it, and will soon stop poking into buffer head internals. Signed-off-by: Christoph Hellwig Reviewed-by: Andreas Gruenbacher Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/buffer.c | 114 ------------------------------------------------------------ 1 file changed, 114 deletions(-) (limited to 'fs/buffer.c') diff --git a/fs/buffer.c b/fs/buffer.c index 249b83fafe48..cabc045f483d 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -3427,120 +3427,6 @@ int bh_submit_read(struct buffer_head *bh) } EXPORT_SYMBOL(bh_submit_read); -/* - * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff. - * - * Returns the offset within the file on success, and -ENOENT otherwise. - */ -static loff_t -page_seek_hole_data(struct page *page, loff_t lastoff, int whence) -{ - loff_t offset = page_offset(page); - struct buffer_head *bh, *head; - bool seek_data = whence == SEEK_DATA; - - if (lastoff < offset) - lastoff = offset; - - bh = head = page_buffers(page); - do { - offset += bh->b_size; - if (lastoff >= offset) - continue; - - /* - * Unwritten extents that have data in the page cache covering - * them can be identified by the BH_Unwritten state flag. - * Pages with multiple buffers might have a mix of holes, data - * and unwritten extents - any buffer with valid data in it - * should have BH_Uptodate flag set on it. - */ - - if ((buffer_unwritten(bh) || buffer_uptodate(bh)) == seek_data) - return lastoff; - - lastoff = offset; - } while ((bh = bh->b_this_page) != head); - return -ENOENT; -} - -/* - * Seek for SEEK_DATA / SEEK_HOLE in the page cache. - * - * Within unwritten extents, the page cache determines which parts are holes - * and which are data: unwritten and uptodate buffer heads count as data; - * everything else counts as a hole. - * - * Returns the resulting offset on successs, and -ENOENT otherwise. - */ -loff_t -page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, - int whence) -{ - pgoff_t index = offset >> PAGE_SHIFT; - pgoff_t end = DIV_ROUND_UP(offset + length, PAGE_SIZE); - loff_t lastoff = offset; - struct pagevec pvec; - - if (length <= 0) - return -ENOENT; - - pagevec_init(&pvec); - - do { - unsigned nr_pages, i; - - nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping, &index, - end - 1); - if (nr_pages == 0) - break; - - for (i = 0; i < nr_pages; i++) { - struct page *page = pvec.pages[i]; - - /* - * At this point, the page may be truncated or - * invalidated (changing page->mapping to NULL), or - * even swizzled back from swapper_space to tmpfs file - * mapping. However, page->index will not change - * because we have a reference on the page. - * - * If current page offset is beyond where we've ended, - * we've found a hole. - */ - if (whence == SEEK_HOLE && - lastoff < page_offset(page)) - goto check_range; - - lock_page(page); - if (likely(page->mapping == inode->i_mapping) && - page_has_buffers(page)) { - lastoff = page_seek_hole_data(page, lastoff, whence); - if (lastoff >= 0) { - unlock_page(page); - goto check_range; - } - } - unlock_page(page); - lastoff = page_offset(page) + PAGE_SIZE; - } - pagevec_release(&pvec); - } while (index < end); - - /* When no page at lastoff and we are not done, we found a hole. */ - if (whence != SEEK_HOLE) - goto not_found; - -check_range: - if (lastoff < offset + length) - goto out; -not_found: - lastoff = -ENOENT; -out: - pagevec_release(&pvec); - return lastoff; -} - void __init buffer_init(void) { unsigned long nrpages; -- cgit v1.2.3