[PATCH v2 03/18] ext4: use ->invalidatepage() length argument

[Lukas Czerner]

->invalidatepage() aop now accepts range to invalidate so we can make
use of it in all ext4 invalidatepage routines.

Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
---
 fs/ext4/inode.c             |   47 ++++++++++++++++++++++++++++++------------
 include/trace/events/ext4.h |   22 +++++++++++---------
 2 files changed, 45 insertions(+), 24 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a3be92c..eb61fb7 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1289,21 +1289,28 @@ static void ext4_da_release_space(struct inode *inode, int to_free)
 }
 
 static void ext4_da_page_release_reservation(struct page *page,
-					     unsigned long offset)
+					     unsigned int offset,
+					     unsigned int length)
 {
 	int to_release = 0;
 	struct buffer_head *head, *bh;
 	unsigned int curr_off = 0;
 	struct inode *inode = page->mapping->host;
 	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	unsigned int stop = offset + length;
 	int num_clusters;
 	ext4_fsblk_t lblk;
 
+	BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
+
 	head = page_buffers(page);
 	bh = head;
 	do {
 		unsigned int next_off = curr_off + bh->b_size;
 
+		if (next_off > stop)
+			break;
+
 		if ((offset <= curr_off) && (buffer_delay(bh))) {
 			to_release++;
 			clear_buffer_delay(bh);
@@ -2709,7 +2716,7 @@ static void ext4_da_invalidatepage(struct page *page, unsigned int offset,
 	if (!page_has_buffers(page))
 		goto out;
 
-	ext4_da_page_release_reservation(page, offset);
+	ext4_da_page_release_reservation(page, offset, length);
 
 out:
 	ext4_invalidatepage(page, offset, length);
@@ -2860,22 +2867,33 @@ ext4_readpages(struct file *file, struct address_space *mapping,
 	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
 }
 
-static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset)
+static void ext4_invalidatepage_free_endio(struct page *page,
+					   unsigned int offset,
+					   unsigned int length)
 {
 	struct buffer_head *head, *bh;
 	unsigned int curr_off = 0;
+	unsigned int stop = offset + length;
 
 	if (!page_has_buffers(page))
 		return;
+
+	BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
+
 	head = bh = page_buffers(page);
 	do {
+		unsigned int next_off = curr_off + bh->b_size;
+
+		if (next_off > stop)
+			return;
+
 		if (offset <= curr_off && test_clear_buffer_uninit(bh)
 					&& bh->b_private) {
 			ext4_free_io_end(bh->b_private);
 			bh->b_private = NULL;
 			bh->b_end_io = NULL;
 		}
-		curr_off = curr_off + bh->b_size;
+		curr_off = next_off;
 		bh = bh->b_this_page;
 	} while (bh != head);
 }
@@ -2883,35 +2901,35 @@ static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offs
 static void ext4_invalidatepage(struct page *page, unsigned int offset,
 				unsigned int length)
 {
-	trace_ext4_invalidatepage(page, offset);
+	trace_ext4_invalidatepage(page, offset, length);
 
 	/*
 	 * free any io_end structure allocated for buffers to be discarded
 	 */
 	if (ext4_should_dioread_nolock(page->mapping->host))
-		ext4_invalidatepage_free_endio(page, offset);
+		ext4_invalidatepage_free_endio(page, offset, length);
 
 	/* No journalling happens on data buffers when this function is used */
 	WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
 
-	block_invalidatepage(page, offset, PAGE_CACHE_SIZE - offset);
+	block_invalidatepage(page, offset, length);
 }
 
 static int __ext4_journalled_invalidatepage(struct page *page,
-					    unsigned long offset)
+					    unsigned int offset,
+					    unsigned int length)
 {
 	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
 
-	trace_ext4_journalled_invalidatepage(page, offset);
+	trace_ext4_journalled_invalidatepage(page, offset, length);
 
 	/*
 	 * If it's a full truncate we just forget about the pending dirtying
 	 */
-	if (offset == 0)
+	if (offset == 0 && length == PAGE_CACHE_SIZE)
 		ClearPageChecked(page);
 
-	return jbd2_journal_invalidatepage(journal, page, offset,
-					   PAGE_CACHE_SIZE - offset);
+	return jbd2_journal_invalidatepage(journal, page, offset, length);
 }
 
 /* Wrapper for aops... */
@@ -2919,7 +2937,7 @@ static void ext4_journalled_invalidatepage(struct page *page,
 					   unsigned int offset,
 					   unsigned int length)
 {
-	WARN_ON(__ext4_journalled_invalidatepage(page, offset) < 0);
+	WARN_ON(__ext4_journalled_invalidatepage(page, offset, length) < 0);
 }
 
 static int ext4_releasepage(struct page *page, gfp_t wait)
@@ -4351,7 +4369,8 @@ static void ext4_wait_for_tail_page_commit(struct inode *inode)
 				      inode->i_size >> PAGE_CACHE_SHIFT);
 		if (!page)
 			return;
-		ret = __ext4_journalled_invalidatepage(page, offset);
+		ret = __ext4_journalled_invalidatepage(page, offset,
+						PAGE_CACHE_SIZE - offset);
 		unlock_page(page);
 		page_cache_release(page);
 		if (ret != -EBUSY)
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 7e8c36b..6ab6f8a 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -452,16 +452,16 @@ DEFINE_EVENT(ext4__page_op, ext4_releasepage,
 );
 
 DECLARE_EVENT_CLASS(ext4_invalidatepage_op,
-	TP_PROTO(struct page *page, unsigned long offset),
+	TP_PROTO(struct page *page, unsigned int offset, unsigned int length),
 
-	TP_ARGS(page, offset),
+	TP_ARGS(page, offset, length),
 
 	TP_STRUCT__entry(
 		__field(	dev_t,	dev			)
 		__field(	ino_t,	ino			)
 		__field(	pgoff_t, index			)
-		__field(	unsigned long, offset		)
-
+		__field(	unsigned int, offset		)
+		__field(	unsigned int, length		)
 	),
 
 	TP_fast_assign(
@@ -469,24 +469,26 @@ DECLARE_EVENT_CLASS(ext4_invalidatepage_op,
 		__entry->ino	= page->mapping->host->i_ino;
 		__entry->index	= page->index;
 		__entry->offset	= offset;
+		__entry->length	= length;
 	),
 
-	TP_printk("dev %d,%d ino %lu page_index %lu offset %lu",
+	TP_printk("dev %d,%d ino %lu page_index %lu offset %u length %u",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  (unsigned long) __entry->ino,
-		  (unsigned long) __entry->index, __entry->offset)
+		  (unsigned long) __entry->index,
+		  __entry->offset, __entry->length)
 );
 
 DEFINE_EVENT(ext4_invalidatepage_op, ext4_invalidatepage,
-	TP_PROTO(struct page *page, unsigned long offset),
+	TP_PROTO(struct page *page, unsigned int offset, unsigned int length),
 
-	TP_ARGS(page, offset)
+	TP_ARGS(page, offset, length)
 );
 
 DEFINE_EVENT(ext4_invalidatepage_op, ext4_journalled_invalidatepage,
-	TP_PROTO(struct page *page, unsigned long offset),
+	TP_PROTO(struct page *page, unsigned int offset, unsigned int length),
 
-	TP_ARGS(page, offset)
+	TP_ARGS(page, offset, length)
 );
 
 TRACE_EVENT(ext4_discard_blocks,
-- 
1.7.7.6

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