[PATCH 4/4] ext3: Add replace-on-rename hueristics for data=writeback mode

Theodore Ts'o
2009-04-03T07:01:11Z

In data=writeback mode, start an asynchronous flush when renaming a
file on top of an already-existing file. This lowers the probability
of data loss in the case of applications that attempt to replace a
file via using rename().

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
fs/ext3/namei.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index 4db4ffa..ab98a66 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -2265,7 +2265,7 @@ static int ext3_rename (struct inode * old_dir, struct dentry *old_dentry,
struct inode * old_inode, * new_inode;
struct buffer_head * old_bh, * new_bh, * dir_bh;
struct ext3_dir_entry_2 * old_de, * new_de;
- int retval;
+ int retval, flush_file = 0;

old_bh = new_bh = dir_bh = NULL;

@@ -2401,6 +2401,8 @@ static int ext3_rename (struct inode * old_dir, struct dentry *old_dentry,
ext3_mark_inode_dirty(handle, new_inode);
if (!new_inode->i_nlink)
ext3_orphan_add(handle, new_inode);
+ if (ext3_should_writeback_data(new_inode))
+ flush_file = 1;
}
retval = 0;

@@ -2409,6 +2411,8 @@ end_rename:
brelse (old_bh);
brelse (new_bh);
ext3_journal_stop(handle);
+ if (retval == 0 && flush_file)
+ filemap_flush(old_inode->i_mapping);
return retval;
}

--
1.5.6.3