iomap SEEK_HOLE / SEEK_DATA cleanups and generalization

index 249b83fafe48..cabc045f483d 100644
@@ -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;

128 lines not on this page · raw message

index 894e5d125de6..96225a77c112 100644
@@ -205,8 +205,6 @@ void write_boundary_block(struct block_device *bdev,
 			sector_t bblock, unsigned blocksize);
 int bh_uptodate_or_lock(struct buffer_head *bh);
 int bh_submit_read(struct buffer_head *bh);
-loff_t page_cache_seek_hole_data(struct inode *inode, loff_t offset,
-				 loff_t length, int whence);
 
 extern int buffer_heads_over_limit;
 

index c2d4fd551fed..e75153f52748 100644
@@ -816,14 +816,9 @@ page_seek_hole_data(struct page *page, loff_t lastoff, int whence)
 			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.
+		 * Any buffer with valid data in it should have BH_Uptodate set.
 		 */
-
-		if ((buffer_unwritten(bh) || buffer_uptodate(bh)) == seek_data)
+		if (buffer_uptodate(bh) == seek_data)
 			return lastoff;
 
 		lastoff = offset;

@@ -835,8 +830,8 @@ page_seek_hole_data(struct page *page, loff_t lastoff, int whence)
  * 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.
+ * and which are data: uptodate buffer heads count as data; everything else
+ * counts as a hole.
  *
  * Returns the resulting offset on successs, and -ENOENT otherwise.
  */

index e75153f52748..5b92243808d3 100644
@@ -794,36 +794,51 @@ int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,
 }
 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.
- */
-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;
+	}
+
+	/*
+	 * 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;
 
-		lastoff = offset;
-	} while ((bh = bh->b_this_page) != head);
-	return -ENOENT;
+	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;
 }
 
 /*

@@ -860,30 +875,8 @@ 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);