linux-ext4 - [PATCH] ext4: Cleanup ext4_sync

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Date:	Wed,  6 Jul 2016 15:54:22 +0200
From:	Jan Kara <jack@...e.cz>
To:	Ted Tso <tytso@....edu>
Cc:	linux-ext4@...r.kernel.org, Al Viro <viro@...IV.linux.org.uk>,
	Jan Kara <jack@...e.cz>
Subject: [PATCH] ext4: Cleanup ext4_sync_parent()

A condition !hlist_empty(&inode->i_dentry) is always true for open file.
Just remove it. Also ext4_sync_parent() could use some explanation why
races with rmdir() are not an issue - add a comment explaining that.

Reported-by: Al Viro <viro@...IV.linux.org.uk>
Signed-off-by: Jan Kara <jack@...e.cz>
---
 fs/ext4/fsync.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 8850254136ae..9b9335796fbc 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -61,6 +61,13 @@ static int ext4_sync_parent(struct inode *inode)
 			break;
 		iput(inode);
 		inode = next;
+		/*
+		 * The directory inode may have gone through rmdir by now. But
+		 * the inode itself and its blocks are still allocated (we hold
+		 * a reference to the inode so it didn't go through
+		 * ext4_evict_inode()) and so we are safe to flush metadata
+		 * blocks and the inode.
+		 */
 		ret = sync_mapping_buffers(inode->i_mapping);
 		if (ret)
 			break;
@@ -107,7 +114,7 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 
 	if (!journal) {
 		ret = generic_file_fsync(file, start, end, datasync);
-		if (!ret && !hlist_empty(&inode->i_dentry))
+		if (!ret)
 			ret = ext4_sync_parent(inode);
 		goto out;
 	}
-- 
2.6.6

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