From 5bb07e6473ed6902fbe37d5d2b972ed4b5ca51be Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 1 Jun 2018 09:05:15 -0700 Subject: [PATCH] fs: use ->is_partially_uptodate in page_cache_seek_hole_data This way the implementation doesn't depend on 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/iomap.c | 83 ++++++++++++++++++++++++++---------------------------- 1 file changed, 40 insertions(+), 43 deletions(-) diff --git a/fs/iomap.c b/fs/iomap.c index 2a20d50f0c1d5..206539d369a84 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -595,34 +595,53 @@ EXPORT_SYMBOL_GPL(iomap_fiemap); /* * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff. - * - * Returns the offset within the file on success, and -ENOENT otherwise. + * Returns true if found and updates @lastoff to the offset in file. */ -static loff_t -page_seek_hole_data(struct page *page, loff_t lastoff, int whence) +static bool +page_seek_hole_data(struct inode *inode, struct page *page, loff_t *lastoff, + int whence) { - loff_t offset = page_offset(page); - struct buffer_head *bh, *head; + const struct address_space_operations *ops = inode->i_mapping->a_ops; + unsigned int bsize = i_blocksize(inode), off; bool seek_data = whence == SEEK_DATA; + loff_t poff = page_offset(page); - if (lastoff < offset) - lastoff = offset; - - bh = head = page_buffers(page); - do { - offset += bh->b_size; - if (lastoff >= offset) - continue; + if (WARN_ON_ONCE(*lastoff >= poff + PAGE_SIZE)) + return false; + if (*lastoff < poff) { /* - * Any buffer with valid data in it should have BH_Uptodate set. + * Last offset smaller than the start of the page means we found + * a hole: */ - if (buffer_uptodate(bh) == seek_data) - return lastoff; + if (whence == SEEK_HOLE) + return true; + *lastoff = poff; + } - lastoff = offset; - } while ((bh = bh->b_this_page) != head); - return -ENOENT; + /* + * Just check the page unless we can and should check block ranges: + */ + if (bsize == PAGE_SIZE || !ops->is_partially_uptodate) + return PageUptodate(page) == seek_data; + + lock_page(page); + if (unlikely(page->mapping != inode->i_mapping)) + goto out_unlock_not_found; + + for (off = 0; off < PAGE_SIZE; off += bsize) { + if ((*lastoff & ~PAGE_MASK) >= off + bsize) + continue; + if (ops->is_partially_uptodate(page, off, bsize) == seek_data) { + unlock_page(page); + return true; + } + *lastoff = poff + off + bsize; + } + +out_unlock_not_found: + unlock_page(page); + return false; } /* @@ -659,30 +678,8 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, 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)) + if (page_seek_hole_data(inode, page, &lastoff, whence)) 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); -- 2.39.5