linux-ext4 - [PATCH 3/4] ext4: avoid calling ext4_mark_inode

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Message-Id: <20170112034938.5934-5-tytso@mit.edu>
Date:   Wed, 11 Jan 2017 22:49:37 -0500
From:   Theodore Ts'o <tytso@....edu>
To:     Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:     linux@...encehorizons.net, Theodore Ts'o <tytso@....edu>
Subject: [PATCH 3/4] ext4: avoid calling ext4_mark_inode_dirty() under unneeded semaphores

There is no need to call ext4_mark_inode_dirty while holding xattr_sem
or i_data_sem, so where it's easy to avoid it, move it out from the
critical region.

Signed-off-by: Theodore Ts'o <tytso@....edu>
---
 fs/ext4/inline.c | 9 +++------
 fs/ext4/inode.c  | 2 +-
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 99a5312ced52..31f98dd04e51 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1042,7 +1042,6 @@ static int ext4_add_dirent_to_inline(handle_t *handle,
 	dir->i_mtime = dir->i_ctime = current_time(dir);
 	ext4_update_dx_flag(dir);
 	dir->i_version++;
-	ext4_mark_inode_dirty(handle, dir);
 	return 1;
 }
 
@@ -1311,8 +1310,8 @@ int ext4_try_add_inline_entry(handle_t *handle, struct ext4_filename *fname,
 	ret = ext4_convert_inline_data_nolock(handle, dir, &iloc);
 
 out:
-	ext4_mark_inode_dirty(handle, dir);
 	ext4_write_unlock_xattr(dir, &no_expand);
+	ext4_mark_inode_dirty(handle, dir);
 	brelse(iloc.bh);
 	return ret;
 }
@@ -1708,13 +1707,11 @@ int ext4_delete_inline_entry(handle_t *handle,
 	if (err)
 		goto out;
 
-	err = ext4_mark_inode_dirty(handle, dir);
-	if (unlikely(err))
-		goto out;
-
 	ext4_show_inline_dir(dir, iloc.bh, inline_start, inline_size);
 out:
 	ext4_write_unlock_xattr(dir, &no_expand);
+	if (likely(err == 0))
+		err = ext4_mark_inode_dirty(handle, dir);
 	brelse(iloc.bh);
 	if (err != -ENOENT)
 		ext4_std_error(dir->i_sb, err);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 88d57af1b516..86dde0667ccc 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2464,8 +2464,8 @@ static int mpage_map_and_submit_extent(handle_t *handle,
 			disksize = i_size;
 		if (disksize > EXT4_I(inode)->i_disksize)
 			EXT4_I(inode)->i_disksize = disksize;
-		err2 = ext4_mark_inode_dirty(handle, inode);
 		up_write(&EXT4_I(inode)->i_data_sem);
+		err2 = ext4_mark_inode_dirty(handle, inode);
 		if (err2)
 			ext4_error(inode->i_sb,
 				   "Failed to mark inode %lu dirty",
-- 
2.11.0.rc0.7.gbe5a750

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