[PATCH 1/3] kill wait_on_page_writeback_range

[Christoph Hellwig <hch@lst.de>]

All callers really want the more logical filemap_fdatawait_range interface,
so convert them to use it and merge wait_on_page_writeback_range into
filemap_fdatawait_range.


Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/Documentation/filesystems/vfs.txt
===================================================================
--- linux-2.6.orig/Documentation/filesystems/vfs.txt	2009-09-30 13:43:04.670028719 -0300
+++ linux-2.6/Documentation/filesystems/vfs.txt	2009-09-30 13:43:11.088004004 -0300
@@ -472,7 +472,7 @@ __sync_single_inode) to check if ->write
 writing out the whole address_space.
 
 The Writeback tag is used by filemap*wait* and sync_page* functions,
-via wait_on_page_writeback_range, to wait for all writeback to
+via filemap_fdatawait_range, to wait for all writeback to
 complete.  While waiting ->sync_page (if defined) will be called on
 each page that is found to require writeback.
 
Index: linux-2.6/fs/jbd2/commit.c
===================================================================
--- linux-2.6.orig/fs/jbd2/commit.c	2009-09-30 13:43:04.644024427 -0300
+++ linux-2.6/fs/jbd2/commit.c	2009-09-30 13:43:11.089004202 -0300
@@ -286,7 +286,7 @@ static int journal_finish_inode_data_buf
 		if (err) {
 			/*
 			 * Because AS_EIO is cleared by
-			 * wait_on_page_writeback_range(), set it again so
+			 * filemap_fdatawait_range(), set it again so
 			 * that user process can get -EIO from fsync().
 			 */
 			set_bit(AS_EIO,
Index: linux-2.6/fs/sync.c
===================================================================
--- linux-2.6.orig/fs/sync.c	2009-09-30 13:43:04.637021859 -0300
+++ linux-2.6/fs/sync.c	2009-09-30 13:43:11.092004514 -0300
@@ -452,9 +452,7 @@ int do_sync_mapping_range(struct address
 
 	ret = 0;
 	if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
-		ret = wait_on_page_writeback_range(mapping,
-					offset >> PAGE_CACHE_SHIFT,
-					endbyte >> PAGE_CACHE_SHIFT);
+		ret = filemap_fdatawait_range(mapping, offset, endbyte);
 		if (ret < 0)
 			goto out;
 	}
@@ -467,9 +465,7 @@ int do_sync_mapping_range(struct address
 	}
 
 	if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
-		ret = wait_on_page_writeback_range(mapping,
-					offset >> PAGE_CACHE_SHIFT,
-					endbyte >> PAGE_CACHE_SHIFT);
+		ret = filemap_fdatawait_range(mapping, offset, endbyte);
 	}
 out:
 	return ret;
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h	2009-09-30 13:43:04.663004220 -0300
+++ linux-2.6/include/linux/fs.h	2009-09-30 13:43:11.096003767 -0300
@@ -2086,8 +2086,6 @@ extern int filemap_fdatawait_range(struc
 extern int filemap_write_and_wait(struct address_space *mapping);
 extern int filemap_write_and_wait_range(struct address_space *mapping,
 				        loff_t lstart, loff_t lend);
-extern int wait_on_page_writeback_range(struct address_space *mapping,
-				pgoff_t start, pgoff_t end);
 extern int __filemap_fdatawrite_range(struct address_space *mapping,
 				loff_t start, loff_t end, int sync_mode);
 extern int filemap_fdatawrite_range(struct address_space *mapping,
Index: linux-2.6/mm/filemap.c
===================================================================
--- linux-2.6.orig/mm/filemap.c	2009-09-30 13:43:04.655004248 -0300
+++ linux-2.6/mm/filemap.c	2009-09-30 13:45:00.480006033 -0300
@@ -260,27 +260,27 @@ int filemap_flush(struct address_space *
 EXPORT_SYMBOL(filemap_flush);
 
 /**
- * wait_on_page_writeback_range - wait for writeback to complete
- * @mapping:	target address_space
- * @start:	beginning page index
- * @end:	ending page index
+ * filemap_fdatawait_range - wait for writeback to complete
+ * @mapping:		address space structure to wait for
+ * @start_byte:		offset in bytes where the range starts
+ * @end_byte:		offset in bytes where the range ends (inclusive)
  *
- * Wait for writeback to complete against pages indexed by start->end
- * inclusive
+ * Walk the list of under-writeback pages of the given address space
+ * in the given range and wait for all of them.
  */
-int wait_on_page_writeback_range(struct address_space *mapping,
-				pgoff_t start, pgoff_t end)
+int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte,
+			    loff_t end_byte)
 {
+	pgoff_t index = start_byte >> PAGE_CACHE_SHIFT;
+	pgoff_t end = end_byte >> PAGE_CACHE_SHIFT;
 	struct pagevec pvec;
 	int nr_pages;
 	int ret = 0;
-	pgoff_t index;
 
-	if (end < start)
+	if (end_byte < start_byte)
 		return 0;
 
 	pagevec_init(&pvec, 0);
-	index = start;
 	while ((index <= end) &&
 			(nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
 			PAGECACHE_TAG_WRITEBACK,
@@ -310,25 +310,6 @@ int wait_on_page_writeback_range(struct 
 
 	return ret;
 }
-
-/**
- * filemap_fdatawait_range - wait for all under-writeback pages to complete in a given range
- * @mapping: address space structure to wait for
- * @start:	offset in bytes where the range starts
- * @end:	offset in bytes where the range ends (inclusive)
- *
- * Walk the list of under-writeback pages of the given address space
- * in the given range and wait for all of them.
- *
- * This is just a simple wrapper so that callers don't have to convert offsets
- * to page indexes themselves
- */
-int filemap_fdatawait_range(struct address_space *mapping, loff_t start,
-			    loff_t end)
-{
-	return wait_on_page_writeback_range(mapping, start >> PAGE_CACHE_SHIFT,
-					    end >> PAGE_CACHE_SHIFT);
-}
 EXPORT_SYMBOL(filemap_fdatawait_range);
 
 /**
@@ -345,8 +326,7 @@ int filemap_fdatawait(struct address_spa
 	if (i_size == 0)
 		return 0;
 
-	return wait_on_page_writeback_range(mapping, 0,
-				(i_size - 1) >> PAGE_CACHE_SHIFT);
+	return filemap_fdatawait_range(mapping, 0, i_size - 1);
 }
 EXPORT_SYMBOL(filemap_fdatawait);
 
@@ -393,9 +373,8 @@ int filemap_write_and_wait_range(struct 
 						 WB_SYNC_ALL);
 		/* See comment of filemap_write_and_wait() */
 		if (err != -EIO) {
-			int err2 = wait_on_page_writeback_range(mapping,
-						lstart >> PAGE_CACHE_SHIFT,
-						lend >> PAGE_CACHE_SHIFT);
+			int err2 = filemap_fdatawait_range(mapping,
+						lstart, lend);
 			if (!err)
 				err = err2;
 		}