get rid of block_write_begin_newtrunc

Move the call to vmtruncate to get rid of accessive blocks to the callers
in preparation of the new truncate sequence and rename the non-truncating
version to block_write_begin.

While we're at it also remove several unused arguments to block_write_begin.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/bfs/file.c

@@ -168,9 +168,17 @@ static int bfs_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
-	*pagep = NULL;
-	return block_write_begin(file, mapping, pos, len, flags,
-					pagep, fsdata, bfs_get_block);
+	int ret;
+
+	ret = block_write_begin(mapping, pos, len, flags, pagep,
+				bfs_get_block);
+	if (unlikely(ret)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+	}
+
+	return ret;
 }
 
 static sector_t bfs_bmap(struct address_space *mapping, sector_t block)

fs/block_dev.c

@@ -308,9 +308,8 @@ static int blkdev_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
-	*pagep = NULL;
-	return block_write_begin_newtrunc(file, mapping, pos, len, flags,
-				pagep, fsdata, blkdev_get_block);
+	return block_write_begin(mapping, pos, len, flags, pagep,
+				 blkdev_get_block);
 }
 
 static int blkdev_write_end(struct file *file, struct address_space *mapping,

fs/buffer.c

@@ -1962,14 +1962,13 @@ int __block_write_begin(struct page *page, loff_t pos, unsigned len,
 EXPORT_SYMBOL(__block_write_begin);
 
 /*
- * Filesystems implementing the new truncate sequence should use the
- * _newtrunc postfix variant which won't incorrectly call vmtruncate.
+ * block_write_begin takes care of the basic task of block allocation and
+ * bringing partial write blocks uptodate first.
+ *
  * The filesystem needs to handle block truncation upon failure.
  */
-int block_write_begin_newtrunc(struct file *file, struct address_space *mapping,
-			loff_t pos, unsigned len, unsigned flags,
-			struct page **pagep, void **fsdata,
-			get_block_t *get_block)
+int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
+		unsigned flags, struct page **pagep, get_block_t *get_block)
 {
 	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 	struct page *page;
@@ -1989,44 +1988,6 @@ int block_write_begin_newtrunc(struct file *file, struct address_space *mapping,
 	*pagep = page;
 	return status;
 }
-EXPORT_SYMBOL(block_write_begin_newtrunc);
-
-/*
- * block_write_begin takes care of the basic task of block allocation and
- * bringing partial write blocks uptodate first.
- *
- * If *pagep is not NULL, then block_write_begin uses the locked page
- * at *pagep rather than allocating its own. In this case, the page will
- * not be unlocked or deallocated on failure.
- */
-int block_write_begin(struct file *file, struct address_space *mapping,
-			loff_t pos, unsigned len, unsigned flags,
-			struct page **pagep, void **fsdata,
-			get_block_t *get_block)
-{
-	int ret;
-
-	ret = block_write_begin_newtrunc(file, mapping, pos, len, flags,
-					pagep, fsdata, get_block);
-
-	/*
-	 * prepare_write() may have instantiated a few blocks
-	 * outside i_size.  Trim these off again. Don't need
-	 * i_size_read because we hold i_mutex.
-	 *
-	 * Filesystems which pass down their own page also cannot
-	 * call into vmtruncate here because it would lead to lock
-	 * inversion problems (*pagep is locked). This is a further
-	 * example of where the old truncate sequence is inadequate.
-	 */
-	if (unlikely(ret) && *pagep == NULL) {
-		loff_t isize = mapping->host->i_size;
-		if (pos + len > isize)
-			vmtruncate(mapping->host, isize);
-	}
-
-	return ret;
-}
 EXPORT_SYMBOL(block_write_begin);
 
 int block_write_end(struct file *file, struct address_space *mapping,
@@ -2357,7 +2318,7 @@ int cont_write_begin(struct file *file, struct address_space *mapping,
 
 	err = cont_expand_zero(file, mapping, pos, bytes);
 	if (err)
-		goto out;
+		return err;
 
 	zerofrom = *bytes & ~PAGE_CACHE_MASK;
 	if (pos+len > *bytes && zerofrom & (blocksize-1)) {
@@ -2365,11 +2326,7 @@ int cont_write_begin(struct file *file, struct address_space *mapping,
 		(*bytes)++;
 	}
 
-	*pagep = NULL;
-	err = block_write_begin_newtrunc(file, mapping, pos, len,
-				flags, pagep, fsdata, get_block);
-out:
-	return err;
+	return block_write_begin(mapping, pos, len, flags, pagep, get_block);
 }
 EXPORT_SYMBOL(cont_write_begin);
 
@@ -2511,8 +2468,8 @@ int nobh_write_begin(struct address_space *mapping,
 		unlock_page(page);
 		page_cache_release(page);
 		*pagep = NULL;
-		return block_write_begin_newtrunc(NULL, mapping, pos, len,
-					flags, pagep, fsdata, get_block);
+		return block_write_begin(mapping, pos, len, flags, pagep,
+					 get_block);
 	}
 
 	if (PageMappedToDisk(page))

fs/ext2/inode.c

@@ -772,9 +772,8 @@ ext2_write_begin(struct file *file, struct address_space *mapping,
 {
 	int ret;
 
-	*pagep = NULL;
-	ret = block_write_begin_newtrunc(file, mapping, pos, len, flags,
-					 pagep, fsdata, ext2_get_block);
+	ret = block_write_begin(mapping, pos, len, flags, pagep,
+				ext2_get_block);
 	if (ret < 0)
 		ext2_write_failed(mapping, pos + len);
 	return ret;

fs/minix/inode.c

@@ -366,9 +366,17 @@ static int minix_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
-	*pagep = NULL;
-	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
+	int ret;
+
+	ret = block_write_begin(mapping, pos, len, flags, pagep,
 				minix_get_block);
+	if (unlikely(ret)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+	}
+
+	return ret;
 }
 
 static sector_t minix_bmap(struct address_space *mapping, sector_t block)

fs/nilfs2/inode.c

@@ -197,11 +197,15 @@ static int nilfs_write_begin(struct file *file, struct address_space *mapping,
 	if (unlikely(err))
 		return err;
 
-	*pagep = NULL;
-	err = block_write_begin(file, mapping, pos, len, flags, pagep,
-				fsdata, nilfs_get_block);
-	if (unlikely(err))
+	err = block_write_begin(mapping, pos, len, flags, pagep,
+				nilfs_get_block);
+	if (unlikely(err)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+
 		nilfs_transaction_abort(inode->i_sb);
+	}
 	return err;
 }
 

fs/nilfs2/recovery.c

@@ -505,11 +505,14 @@ static int recover_dsync_blocks(struct nilfs_sb_info *sbi,
 		}
 
 		pos = rb->blkoff << inode->i_blkbits;
-		page = NULL;
-		err = block_write_begin(NULL, inode->i_mapping, pos, blocksize,
-					0, &page, NULL, nilfs_get_block);
-		if (unlikely(err))
+		err = block_write_begin(inode->i_mapping, pos, blocksize,
+					0, &page, nilfs_get_block);
+		if (unlikely(err)) {
+			loff_t isize = inode->i_size;
+			if (pos + blocksize > isize)
+				vmtruncate(inode, isize);
 			goto failed_inode;
+		}
 
 		err = nilfs_recovery_copy_block(sbi, rb, page);
 		if (unlikely(err))

fs/omfs/file.c

@@ -312,9 +312,17 @@ static int omfs_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
-	*pagep = NULL;
-	return block_write_begin(file, mapping, pos, len, flags,
-				pagep, fsdata, omfs_get_block);
+	int ret;
+
+	ret = block_write_begin(mapping, pos, len, flags, pagep,
+				omfs_get_block);
+	if (unlikely(ret)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+	}
+
+	return ret;
 }
 
 static sector_t omfs_bmap(struct address_space *mapping, sector_t block)

fs/sysv/itree.c

@@ -468,9 +468,16 @@ static int sysv_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
-	*pagep = NULL;
-	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-				get_block);
+	int ret;
+
+	ret = block_write_begin(mapping, pos, len, flags, pagep, get_block);
+	if (unlikely(ret)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+	}
+
+	return ret;
 }
 
 static sector_t sysv_bmap(struct address_space *mapping, sector_t block)

fs/udf/inode.c

@@ -127,9 +127,16 @@ static int udf_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
-	*pagep = NULL;
-	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-				udf_get_block);
+	int ret;
+
+	ret = block_write_begin(mapping, pos, len, flags, pagep, udf_get_block);
+	if (unlikely(ret)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+	}
+
+	return ret;
 }
 
 static sector_t udf_bmap(struct address_space *mapping, sector_t block)

fs/ufs/inode.c

@@ -567,9 +567,17 @@ static int ufs_write_begin(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
-	*pagep = NULL;
-	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
+	int ret;
+
+	ret = block_write_begin(mapping, pos, len, flags, pagep,
 				ufs_getfrag_block);
+	if (unlikely(ret)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+	}
+
+	return ret;
 }
 
 static sector_t ufs_bmap(struct address_space *mapping, sector_t block)

fs/xfs/linux-2.6/xfs_aops.c

@@ -1504,9 +1504,17 @@ xfs_vm_write_begin(
 	struct page		**pagep,
 	void			**fsdata)
 {
-	*pagep = NULL;
-	return block_write_begin(file, mapping, pos, len, flags | AOP_FLAG_NOFS,
-				 pagep, fsdata, xfs_get_blocks);
+	int			ret;
+
+	ret = block_write_begin(mapping, pos, len, flags | AOP_FLAG_NOFS,
+				pagep, xfs_get_blocks);
+	if (unlikely(ret)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+	}
+
+	return ret;
 }
 
 STATIC sector_t

include/linux/buffer_head.h

@@ -203,12 +203,8 @@ int block_write_full_page_endio(struct page *page, get_block_t *get_block,
 int block_read_full_page(struct page*, get_block_t*);
 int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc,
 				unsigned long from);
-int block_write_begin_newtrunc(struct file *, struct address_space *,
-				loff_t, unsigned, unsigned,
-				struct page **, void **, get_block_t*);
-int block_write_begin(struct file *, struct address_space *,
-				loff_t, unsigned, unsigned,
-				struct page **, void **, get_block_t*);
+int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
+		unsigned flags, struct page **pagep, get_block_t *get_block);
 int __block_write_begin(struct page *page, loff_t pos, unsigned len,
 		get_block_t *get_block);
 int block_write_end(struct file *, struct address_space *,