[PATCH] ensure file size is logged on synchronous writes

[PATCH] ensure file size is logged on synchronous writes

[Lachlan McIlroy]

[-- Attachment #1: Type: text/plain, Size: 334 bytes --]

Synchronous writes currently log inode changes before syncing
pages to disk.  Since the file size is updated on I/O completion
we wont be writing out the updated file size and if we crash the
file will have the wrong size.  This change moves the logging
after the syncing of the pages to ensure we log the correct file
size.

Lachlan

[-- Attachment #2: xfs_write.diff --]
[-- Type: text/x-patch, Size: 815 bytes --]

--- fs/xfs/linux-2.6/xfs_lrw.c_1.266	2007-08-30 17:38:53.000000000 +1000
+++ fs/xfs/linux-2.6/xfs_lrw.c	2007-08-31 15:38:49.000000000 +1000
@@ -895,20 +895,19 @@ retry:
 
 	/* Handle various SYNC-type writes */
 	if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
-		error = xfs_write_sync_logforce(mp, xip);
-		if (error)
-			goto out_unlock_internal;
-
+		int error2;
 		xfs_rwunlock(xip, locktype);
 		if (need_i_mutex)
 			mutex_unlock(&inode->i_mutex);
-
-		error = sync_page_range(inode, mapping, pos, ret);
+		error2 = sync_page_range(inode, mapping, pos, ret);
 		if (!error)
-			error = -ret;
+			error = error2;
 		if (need_i_mutex)
 			mutex_lock(&inode->i_mutex);
 		xfs_rwlock(xip, locktype);
+		error2 = xfs_write_sync_logforce(mp, xip);
+		if (!error)
+			error = error2;
 	}
 
  out_unlock_internal:

Re: [PATCH] ensure file size is logged on synchronous writes

[Christoph Hellwig]

On Mon, Sep 03, 2007 at 01:07:12PM +1000, Lachlan McIlroy wrote:
> Synchronous writes currently log inode changes before syncing
> pages to disk.  Since the file size is updated on I/O completion
> we wont be writing out the updated file size and if we crash the
> file will have the wrong size.  This change moves the logging
> after the syncing of the pages to ensure we log the correct file
> size.

Looks good to me.