Re: [PATCH] UBIFS: kill BKL

[Artem Bityutskiy <dedekind1@gmail.com>]

On Mon, 2009-07-20 at 08:51 -0400, Christoph Hellwig wrote:
> On something slightly related - anohter part of the super_ops
> rework in 2.6.31 was that we now always push data out before calling
> into ->sync_fs to synchronize the metadata.
> 
> This means the generic_sync_sb_inodes call in ubifs_sync_fs should go
> away now.

Yes, indeed '__sync_filesystem()' invokes 'sync_inodes_sb()' before
'->sync_sb()'. Thanks for pointing this out. Below is the patch.

>From c14ed92bf8639c8533f8e923859b136d0671db1b Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Date: Mon, 20 Jul 2009 17:56:19 +0300
Subject: [PATCH] UBIFS: remove unneeded call from ubifs_sync_fs

Nowadays VFS always synchronizes all dirty inodes and pages before
calling '->sync_fs()', so remove unneeded 'generic_sync_sb_inodes()'
from 'ubifs_sync_fs()'. It used to be needed, but not any longer.

Pointed-out-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
---
 fs/ubifs/super.c |   24 +++++++-----------------
 1 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 13e7ed4..b541bd7 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -437,12 +437,6 @@ static int ubifs_sync_fs(struct super_block *sb, int wait)
 {
 	int i, err;
 	struct ubifs_info *c = sb->s_fs_info;
-	struct writeback_control wbc = {
-		.sync_mode   = WB_SYNC_ALL,
-		.range_start = 0,
-		.range_end   = LLONG_MAX,
-		.nr_to_write = LONG_MAX,
-	};
 
 	/*
 	 * Zero @wait is just an advisory thing to help the file system shove
@@ -453,17 +447,6 @@ static int ubifs_sync_fs(struct super_block *sb, int wait)
 		return 0;
 
 	/*
-	 * VFS calls '->sync_fs()' before synchronizing all dirty inodes and
-	 * pages, so synchronize them first, then commit the journal. Strictly
-	 * speaking, it is not necessary to commit the journal here,
-	 * synchronizing write-buffers would be enough. But committing makes
-	 * UBIFS free space predictions much more accurate, so we want to let
-	 * the user be able to get more accurate results of 'statfs()' after
-	 * they synchronize the file system.
-	 */
-	generic_sync_sb_inodes(sb, &wbc);
-
-	/*
 	 * Synchronize write buffers, because 'ubifs_run_commit()' does not
 	 * do this if it waits for an already running commit.
 	 */
@@ -473,6 +456,13 @@ static int ubifs_sync_fs(struct super_block *sb, int wait)
 			return err;
 	}
 
+	/*
+	 * Strictly speaking, it is not necessary to commit the journal here,
+	 * synchronizing write-buffers would be enough. But committing makes
+	 * UBIFS free space predictions much more accurate, so we want to let
+	 * the user be able to get more accurate results of 'statfs()' after
+	 * they synchronize the file system.
+	 */
 	err = ubifs_run_commit(c);
 	if (err)
 		return err;
-- 
1.6.0.6

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

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