mm: change invalidatepage prototype to accept length

Currently there is no way to truncate partial page where the end
truncate point is not at the end of the page. This is because it was not
needed and the functionality was enough for file system truncate
operation to work properly. However more file systems now support punch
hole feature and it can benefit from mm supporting truncating page just
up to the certain point.

Specifically, with this functionality truncate_inode_pages_range() can
be changed so it supports truncating partial page at the end of the
range (currently it will BUG_ON() if 'end' is not at the end of the
page).

This commit changes the invalidatepage() address space operation
prototype to accept range to be invalidated and update all the instances
for it.

We also change the block_invalidatepage() in the same way and actually
make a use of the new length argument implementing range invalidation.

Actual file system implementations will follow except the file systems
where the changes are really simple and should not change the behaviour
in any way .Implementation for truncate_page_range() which will be able
to accept page unaligned ranges will follow as well.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>

23 files changed, 88 insertions, 46 deletions

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 055562c..9ff073f 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -148,13 +148,14 @@ static int v9fs_release_page(struct page *page, gfp_t gfp)
  * @offset: offset in the page
  */
 
-static void v9fs_invalidate_page(struct page *page, unsigned long offset)
+static void v9fs_invalidate_page(struct page *page, unsigned int offset,
+				 unsigned int length)
 {
 	/*
 	 * If called with zero offset, we should release
 	 * the private state assocated with the page
 	 */
-	if (offset == 0)
+	if (offset == 0 && length == PAGE_CACHE_SIZE)
 		v9fs_fscache_invalidate_page(page);
 }
 
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 8f6e923..66d50fe 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -19,7 +19,8 @@
 #include "internal.h"
 
 static int afs_readpage(struct file *file, struct page *page);
-static void afs_invalidatepage(struct page *page, unsigned long offset);
+static void afs_invalidatepage(struct page *page, unsigned int offset,
+			       unsigned int length);
 static int afs_releasepage(struct page *page, gfp_t gfp_flags);
 static int afs_launder_page(struct page *page);
 
@@ -310,16 +311,17 @@ static int afs_launder_page(struct page *page)
  * - release a page and clean up its private data if offset is 0 (indicating
  *   the entire page)
  */
-static void afs_invalidatepage(struct page *page, unsigned long offset)
+static void afs_invalidatepage(struct page *page, unsigned int offset,
+			       unsigned int length)
 {
 	struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
 
-	_enter("{%lu},%lu", page->index, offset);
+	_enter("{%lu},%u,%u", page->index, offset, length);
 
 	BUG_ON(!PageLocked(page));
 
 	/* we clean up only if the entire page is being invalidated */
-	if (offset == 0) {
+	if (offset == 0 && length == PAGE_CACHE_SIZE) {
 #ifdef CONFIG_AFS_FSCACHE
 		if (PageFsCache(page)) {
 			struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e7b3cb5..40c7bc3 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1013,7 +1013,8 @@ static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 	return try_release_extent_buffer(page);
 }
 
-static void btree_invalidatepage(struct page *page, unsigned long offset)
+static void btree_invalidatepage(struct page *page, unsigned int offset,
+				 unsigned int length)
 {
 	struct extent_io_tree *tree;
 	tree = &BTRFS_I(page->mapping->host)->io_tree;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index e7e7afb..6bca947 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2957,7 +2957,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	pg_offset = i_size & (PAGE_CACHE_SIZE - 1);
 	if (page->index > end_index ||
 	   (page->index == end_index && !pg_offset)) {
-		page->mapping->a_ops->invalidatepage(page, 0);
+		page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
 		unlock_page(page);
 		return 0;
 	}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index af978f7..db57e63 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7510,7 +7510,8 @@ static int btrfs_releasepage(struct page *page, gfp_t gfp_flags)
 	return __btrfs_releasepage(page, gfp_flags & GFP_NOFS);
 }
 
-static void btrfs_invalidatepage(struct page *page, unsigned long offset)
+static void btrfs_invalidatepage(struct page *page, unsigned int offset,
+				 unsigned int length)
 {
 	struct inode *inode = page->mapping->host;
 	struct extent_io_tree *tree;
diff --git a/fs/buffer.c b/fs/buffer.c
index d2a4d1b..f93392e 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1454,7 +1454,8 @@ static void discard_buffer(struct buffer_head * bh)
  * block_invalidatepage - invalidate part or all of a buffer-backed page
  *
  * @page: the page which is affected
- * @offset: the index of the truncation point
+ * @offset: start of the range to invalidate
+ * @length: length of the range to invalidate
  *
  * block_invalidatepage() is called when all or part of the page has become
  * invalidated by a truncate operation.
@@ -1465,15 +1466,22 @@ static void discard_buffer(struct buffer_head * bh)
  * point.  Because the caller is about to free (and possibly reuse) those
  * blocks on-disk.
  */
-void block_invalidatepage(struct page *page, unsigned long offset)
+void block_invalidatepage(struct page *page, unsigned int offset,
+			  unsigned int length)
 {
 	struct buffer_head *head, *bh, *next;
 	unsigned int curr_off = 0;
+	unsigned int stop = length + offset;
 
 	BUG_ON(!PageLocked(page));
 	if (!page_has_buffers(page))
 		goto out;
 
+	/*
+	 * Check for overflow
+	 */
+	BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
+
 	head = page_buffers(page);
 	bh = head;
 	do {
@@ -1481,6 +1489,12 @@ void block_invalidatepage(struct page *page, unsigned long offset)
 		next = bh->b_this_page;
 
 		/*
+		 * Are we still fully in range ?
+		 */
+		if (next_off > stop)
+			goto out;
+
+		/*
 		 * is this block fully invalidated?
 		 */
 		if (offset <= curr_off)
@@ -1501,6 +1515,7 @@ out:
 }
 EXPORT_SYMBOL(block_invalidatepage);
 
+
 /*
  * We attach and possibly dirty the buffers atomically wrt
  * __set_page_dirty_buffers() via private_lock.  try_to_free_buffers
@@ -2841,7 +2856,7 @@ int block_write_full_page_endio(struct page *page, get_block_t *get_block,
 		 * they may have been added in ext3_writepage().  Make them
 		 * freeable here, so the page does not leak.
 		 */
-		do_invalidatepage(page, 0);
+		do_invalidatepage(page, 0, PAGE_CACHE_SIZE);
 		unlock_page(page);
 		return 0; /* don't care */
 	}
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 3e68ac1..b189940 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -143,7 +143,8 @@ static int ceph_set_page_dirty(struct page *page)
  * dirty page counters appropriately.  Only called if there is private
  * data on the page.
  */
-static void ceph_invalidatepage(struct page *page, unsigned long offset)
+static void ceph_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length)
 {
 	struct inode *inode;
 	struct ceph_inode_info *ci;
@@ -168,7 +169,7 @@ static void ceph_invalidatepage(struct page *page, unsigned long offset)
 
 	ci = ceph_inode(inode);
 	if (offset == 0) {
-		dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
+		dout("%p invalidatepage %p idx %lu full dirty page %u\n",
 		     inode, page, page->index, offset);
 		ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
 		ceph_put_snap_context(snapc);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 48b29d2..4d8ba8d 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3546,11 +3546,12 @@ static int cifs_release_page(struct page *page, gfp_t gfp)
 	return cifs_fscache_release_page(page, gfp);
 }
 
-static void cifs_invalidate_page(struct page *page, unsigned long offset)
+static void cifs_invalidate_page(struct page *page, unsigned int offset,
+				 unsigned int length)
 {
 	struct cifsInodeInfo *cifsi = CIFS_I(page->mapping->host);
 
-	if (offset == 0)
+	if (offset == 0 && length == PAGE_CACHE_SIZE)
 		cifs_fscache_invalidate_page(page, &cifsi->vfs_inode);
 }
 
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index d1f80ab..2ec8eb1 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -953,9 +953,11 @@ static int exofs_releasepage(struct page *page, gfp_t gfp)
 	return 0;
 }
 
-static void exofs_invalidatepage(struct page *page, unsigned long offset)
+static void exofs_invalidatepage(struct page *page, unsigned int offset,
+				 unsigned int length)
 {
-	EXOFS_DBGMSG("page 0x%lx offset 0x%lx\n", page->index, offset);
+	EXOFS_DBGMSG("page 0x%lx offset 0x%x length 0x%x\n",
+		     page->index, offset, length);
 	WARN_ON(1);
 }
 
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index 23c7128..b6e5934 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1825,7 +1825,8 @@ ext3_readpages(struct file *file, struct address_space *mapping,
 	return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
 }
 
-static void ext3_invalidatepage(struct page *page, unsigned long offset)
+static void ext3_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length)
 {
 	journal_t *journal = EXT3_JOURNAL(page->mapping->host);
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index d6382b8..19d6ca2 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -132,7 +132,8 @@ static inline int ext4_begin_ordered_truncate(struct inode *inode,
 						   new_size);
 }
 
-static void ext4_invalidatepage(struct page *page, unsigned long offset);
+static void ext4_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length);
 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
 static int ext4_discard_partial_page_buffers_no_lock(handle_t *handle,
@@ -1606,7 +1607,7 @@ static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd)
 				break;
 			BUG_ON(!PageLocked(page));
 			BUG_ON(PageWriteback(page));
-			block_invalidatepage(page, 0);
+			block_invalidatepage(page, 0, PAGE_CACHE_SIZE);
 			ClearPageUptodate(page);
 			unlock_page(page);
 		}
@@ -2829,7 +2830,8 @@ static int ext4_da_write_end(struct file *file,
 	return ret ? ret : copied;
 }
 
-static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
+static void ext4_da_invalidatepage(struct page *page, unsigned int offset,
+				   unsigned int length)
 {
 	/*
 	 * Drop reserved blocks
@@ -2841,7 +2843,7 @@ static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
 	ext4_da_page_release_reservation(page, offset);
 
 out:
-	ext4_invalidatepage(page, offset);
+	ext4_invalidatepage(page, offset, length);
 
 	return;
 }
@@ -2989,14 +2991,15 @@ ext4_readpages(struct file *file, struct address_space *mapping,
 	return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
 }
 
-static void ext4_invalidatepage(struct page *page, unsigned long offset)
+static void ext4_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length)
 {
 	trace_ext4_invalidatepage(page, offset);
 
 	/* 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);
+	block_invalidatepage(page, offset, PAGE_CACHE_SIZE - offset);
 }
 
 static int __ext4_journalled_invalidatepage(struct page *page,
@@ -3017,7 +3020,8 @@ static int __ext4_journalled_invalidatepage(struct page *page,
 
 /* Wrapper for aops... */
 static void ext4_journalled_invalidatepage(struct page *page,
-					   unsigned long offset)
+					   unsigned int offset,
+					   unsigned int length)
 {
 	WARN_ON(__ext4_journalled_invalidatepage(page, offset) < 0);
 }
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 91ff93b..ce11d9a 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -698,7 +698,8 @@ static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
 						  get_data_block_ro);
 }
 
-static void f2fs_invalidate_data_page(struct page *page, unsigned long offset)
+static void f2fs_invalidate_data_page(struct page *page, unsigned int offset,
+				      unsigned int length)
 {
 	struct inode *inode = page->mapping->host;
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 3df43b4..74f3c7b 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1205,7 +1205,8 @@ static int f2fs_set_node_page_dirty(struct page *page)
 	return 0;
 }
 
-static void f2fs_invalidate_node_page(struct page *page, unsigned long offset)
+static void f2fs_invalidate_node_page(struct page *page, unsigned int offset,
+				      unsigned int length)
 {
 	struct inode *inode = page->mapping->host;
 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 0bad69e..db0d39f 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -110,7 +110,7 @@ static int gfs2_writepage_common(struct page *page,
 	/* Is the page fully outside i_size? (truncate in progress) */
 	offset = i_size & (PAGE_CACHE_SIZE-1);
 	if (page->index > end_index || (page->index == end_index && !offset)) {
-		page->mapping->a_ops->invalidatepage(page, 0);
+		page->mapping->a_ops->invalidatepage(page, 0, PAGE_CACHE_SIZE);
 		goto out;
 	}
 	return 1;
@@ -299,7 +299,8 @@ static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 
 		/* Is the page fully outside i_size? (truncate in progress) */
 		if (page->index > end_index || (page->index == end_index && !offset)) {
-			page->mapping->a_ops->invalidatepage(page, 0);
+			page->mapping->a_ops->invalidatepage(page, 0,
+							     PAGE_CACHE_SIZE);
 			unlock_page(page);
 			continue;
 		}
@@ -943,7 +944,8 @@ static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
 	unlock_buffer(bh);
 }
 
-static void gfs2_invalidatepage(struct page *page, unsigned long offset)
+static void gfs2_invalidatepage(struct page *page, unsigned int offset,
+				unsigned int length)
 {
 	struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 	struct buffer_head *bh, *head;
diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index 6740d34..9e3aaff 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -571,9 +571,10 @@ static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
 	return ret;
 }
 
-static void metapage_invalidatepage(struct page *page, unsigned long offset)
+static void metapage_invalidatepage(struct page *page, unsigned int offset,
+				    unsigned int length)
 {
-	BUG_ON(offset);
+	BUG_ON(offset || length < PAGE_CACHE_SIZE);
 
 	BUG_ON(PageWriteback(page));
 
diff --git a/fs/logfs/file.c b/fs/logfs/file.c
index c2219a6..57914fc 100644
--- a/fs/logfs/file.c
+++ b/fs/logfs/file.c
@@ -159,7 +159,8 @@ static int logfs_writepage(struct page *page, struct writeback_control *wbc)
 	return __logfs_writepage(page);
 }
 
-static void logfs_invalidatepage(struct page *page, unsigned long offset)
+static void logfs_invalidatepage(struct page *page, unsigned int offset,
+				 unsigned int length)
 {
 	struct logfs_block *block = logfs_block(page);
 
diff --git a/fs/logfs/segment.c b/fs/logfs/segment.c
index 038da09..d448a77 100644
--- a/fs/logfs/segment.c
+++ b/fs/logfs/segment.c
@@ -884,7 +884,8 @@ static struct logfs_area *alloc_area(struct super_block *sb)
 	return area;
 }
 
-static void map_invalidatepage(struct page *page, unsigned long l)
+static void map_invalidatepage(struct page *page, unsigned int o,
+			       unsigned int l)
 {
 	return;
 }
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index a87a44f..6b4a79f 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -451,11 +451,13 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
  * - Called if either PG_private or PG_fscache is set on the page
  * - Caller holds page lock
  */
-static void nfs_invalidate_page(struct page *page, unsigned long offset)
+static void nfs_invalidate_page(struct page *page, unsigned int offset,
+				unsigned int length)
 {
-	dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
+	dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %u, %u)\n",
+		 page, offset, length);
 
-	if (offset != 0)
+	if (offset != 0 || length < PAGE_CACHE_SIZE)
 		return;
 	/* Cancel any unstarted writes on this page */
 	nfs_wb_page_cancel(page_file_mapping(page)->host, page);
diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
index fa9c05f..d267ea6 100644
--- a/fs/ntfs/aops.c
+++ b/fs/ntfs/aops.c
@@ -1372,7 +1372,7 @@ retry_writepage:
 		 * The page may have dirty, unmapped buffers.  Make them
 		 * freeable here, so the page does not leak.
 		 */
-		block_invalidatepage(page, 0);
+		block_invalidatepage(page, 0, PAGE_CACHE_SIZE);
 		unlock_page(page);
 		ntfs_debug("Write outside i_size - truncated?");
 		return 0;
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 20dfec7..ecb86ca 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -603,7 +603,8 @@ static void ocfs2_dio_end_io(struct kiocb *iocb,
  * from ext3.  PageChecked() bits have been removed as OCFS2 does not
  * do journalled data.
  */
-static void ocfs2_invalidatepage(struct page *page, unsigned long offset)
+static void ocfs2_invalidatepage(struct page *page, unsigned int offset,
+				 unsigned int length)
 {
 	journal_t *journal = OCFS2_SB(page->mapping->host->i_sb)->journal->j_journal;
 
diff --git a/fs/reiserfs/inode.c b/fs/reiserfs/inode.c
index 77d6d47..278c86e 100644
--- a/fs/reiserfs/inode.c
+++ b/fs/reiserfs/inode.c
@@ -2970,7 +2970,8 @@ static int invalidatepage_can_drop(struct inode *inode, struct buffer_head *bh)
 }
 
 /* clm -- taken from fs/buffer.c:block_invalidate_page */
-static void reiserfs_invalidatepage(struct page *page, unsigned long offset)
+static void reiserfs_invalidatepage(struct page *page, unsigned int offset,
+				    unsigned int length)
 {
 	struct buffer_head *head, *bh, *next;
 	struct inode *inode = page->mapping->host;
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 1437453..123c79b 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1277,13 +1277,14 @@ int ubifs_setattr(struct dentry *dentry, struct iattr *attr)
 	return err;
 }
 
-static void ubifs_invalidatepage(struct page *page, unsigned long offset)
+static void ubifs_invalidatepage(struct page *page, unsigned int offset,
+				 unsigned int length)
 {
 	struct inode *inode = page->mapping->host;
 	struct ubifs_info *c = inode->i_sb->s_fs_info;
 
 	ubifs_assert(PagePrivate(page));
-	if (offset)
+	if (offset || length < PAGE_CACHE_SIZE)
 		/* Partial page remains dirty */
 		return;
 
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 2b2691b..a8f63f3 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -824,10 +824,11 @@ xfs_cluster_write(
 STATIC void
 xfs_vm_invalidatepage(
 	struct page		*page,
-	unsigned long		offset)
+	unsigned int		offset,
+	unsigned int		length)
 {
 	trace_xfs_invalidatepage(page->mapping->host, page, offset);
-	block_invalidatepage(page, offset);
+	block_invalidatepage(page, offset, PAGE_CACHE_SIZE - offset);
 }
 
 /*
@@ -891,7 +892,7 @@ next_buffer:
 
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
 out_invalidate:
-	xfs_vm_invalidatepage(page, 0);
+	xfs_vm_invalidatepage(page, 0, PAGE_CACHE_SIZE);
 	return;
 }