patch-2.4.18 linux/mm/filemap.c

• Lines: 219
• Date: Tue Jan 22 23:04:47 2002
• Orig file: linux.orig/mm/filemap.c
• Orig date: Mon Feb 18 20:18:40 2002

diff -Naur -X /home/marcelo/lib/dontdiff linux.orig/mm/filemap.c linux/mm/filemap.c
@@ -454,41 +454,6 @@
 	return page;
 }
 
-/*
- * By the time this is called, the page is locked and
- * we don't have to worry about any races any more.
- *
- * Start the IO..
- */
-static int writeout_one_page(struct page *page)
-{
-	struct buffer_head *bh, *head = page->buffers;
-
-	bh = head;
-	do {
-		if (buffer_locked(bh) || !buffer_dirty(bh) || !buffer_uptodate(bh))
-			continue;
-
-		bh->b_flushtime = jiffies;
-		ll_rw_block(WRITE, 1, &bh);	
-	} while ((bh = bh->b_this_page) != head);
-	return 0;
-}
-
-int waitfor_one_page(struct page *page)
-{
-	int error = 0;
-	struct buffer_head *bh, *head = page->buffers;
-
-	bh = head;
-	do {
-		wait_on_buffer(bh);
-		if (buffer_req(bh) && !buffer_uptodate(bh))
-			error = -EIO;
-	} while ((bh = bh->b_this_page) != head);
-	return error;
-}
-
 static int do_buffer_fdatasync(struct list_head *head, unsigned long start, unsigned long end, int (*fn)(struct page *))
 {
 	struct list_head *curr;
@@ -582,8 +547,9 @@
  *      @mapping: address space structure to write
  *
  */
-void filemap_fdatasync(struct address_space * mapping)
+int filemap_fdatasync(struct address_space * mapping)
 {
+	int ret = 0;
 	int (*writepage)(struct page *) = mapping->a_ops->writepage;
 
 	spin_lock(&pagecache_lock);
@@ -603,8 +569,11 @@
 		lock_page(page);
 
 		if (PageDirty(page)) {
+			int err;
 			ClearPageDirty(page);
-			writepage(page);
+			err = writepage(page);
+			if (err && !ret)
+				ret = err;
 		} else
 			UnlockPage(page);
 
@@ -612,6 +581,7 @@
 		spin_lock(&pagecache_lock);
 	}
 	spin_unlock(&pagecache_lock);
+	return ret;
 }
 
 /**
@@ -621,8 +591,10 @@
  *      @mapping: address space structure to wait for
  *
  */
-void filemap_fdatawait(struct address_space * mapping)
+int filemap_fdatawait(struct address_space * mapping)
 {
+	int ret = 0;
+
 	spin_lock(&pagecache_lock);
 
         while (!list_empty(&mapping->locked_pages)) {
@@ -638,11 +610,14 @@
 		spin_unlock(&pagecache_lock);
 
 		___wait_on_page(page);
+		if (PageError(page))
+			ret = -EIO;
 
 		page_cache_release(page);
 		spin_lock(&pagecache_lock);
 	}
 	spin_unlock(&pagecache_lock);
+	return ret;
 }
 
 /*
@@ -941,7 +916,6 @@
 	spin_unlock(&pagecache_lock);
 	if (!page) {
 		struct page *newpage = alloc_page(gfp_mask);
-		page = NULL;
 		if (newpage) {
 			spin_lock(&pagecache_lock);
 			page = __find_lock_page_helper(mapping, index, *hash);
@@ -1520,12 +1494,14 @@
 		goto out_free;
 
 	/*
-	 * Flush to disk exlusively the _data_, metadata must remains
+	 * Flush to disk exclusively the _data_, metadata must remain
 	 * completly asynchronous or performance will go to /dev/null.
 	 */
-	filemap_fdatasync(mapping);
-	retval = fsync_inode_data_buffers(inode);
-	filemap_fdatawait(mapping);
+	retval = filemap_fdatasync(mapping);
+	if (retval == 0)
+		retval = fsync_inode_data_buffers(inode);
+	if (retval == 0)
+		retval = filemap_fdatawait(mapping);
 	if (retval < 0)
 		goto out_free;
 
@@ -2142,26 +2118,45 @@
  * The msync() system call.
  */
 
+/*
+ * MS_SYNC syncs the entire file - including mappings.
+ *
+ * MS_ASYNC initiates writeout of just the dirty mapped data.
+ * This provides no guarantee of file integrity - things like indirect
+ * blocks may not have started writeout.  MS_ASYNC is primarily useful
+ * where the application knows that it has finished with the data and
+ * wishes to intelligently schedule its own I/O traffic.
+ */
 static int msync_interval(struct vm_area_struct * vma,
 	unsigned long start, unsigned long end, int flags)
 {
+	int ret = 0;
 	struct file * file = vma->vm_file;
+
 	if (file && (vma->vm_flags & VM_SHARED)) {
-		int error;
-		error = filemap_sync(vma, start, end-start, flags);
+		ret = filemap_sync(vma, start, end-start, flags);
 
-		if (!error && (flags & MS_SYNC)) {
+		if (!ret && (flags & (MS_SYNC|MS_ASYNC))) {
 			struct inode * inode = file->f_dentry->d_inode;
+
 			down(&inode->i_sem);
-			filemap_fdatasync(inode->i_mapping);
-			if (file->f_op && file->f_op->fsync)
-				error = file->f_op->fsync(file, file->f_dentry, 1);
-			filemap_fdatawait(inode->i_mapping);
+			ret = filemap_fdatasync(inode->i_mapping);
+			if (flags & MS_SYNC) {
+				int err;
+
+				if (file->f_op && file->f_op->fsync) {
+					err = file->f_op->fsync(file, file->f_dentry, 1);
+					if (err && !ret)
+						ret = err;
+				}
+				err = filemap_fdatawait(inode->i_mapping);
+				if (err && !ret)
+					ret = err;
+			}
 			up(&inode->i_sem);
 		}
-		return error;
 	}
-	return 0;
+	return ret;
 }
 
 asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
@@ -3005,7 +3000,7 @@
 		kaddr = kmap(page);
 		status = mapping->a_ops->prepare_write(file, page, offset, offset+bytes);
 		if (status)
-			goto unlock;
+			goto sync_failure;
 		page_fault = __copy_from_user(kaddr+offset, buf, bytes);
 		flush_dcache_page(page);
 		status = mapping->a_ops->commit_write(file, page, offset, offset+bytes);
@@ -3030,6 +3025,7 @@
 		if (status < 0)
 			break;
 	} while (count);
+done:
 	*ppos = pos;
 
 	if (cached_page)
@@ -3051,6 +3047,18 @@
 fail_write:
 	status = -EFAULT;
 	goto unlock;
+
+sync_failure:
+	/*
+	 * If blocksize < pagesize, prepare_write() may have instantiated a
+	 * few blocks outside i_size.  Trim these off again.
+	 */
+	kunmap(page);
+	UnlockPage(page);
+	page_cache_release(page);
+	if (pos + bytes > inode->i_size)
+		vmtruncate(inode, inode->i_size);
+	goto done;
 
 o_direct:
 	written = generic_file_direct_IO(WRITE, file, (char *) buf, count, pos);