ext4: Automatically allocate delay allocated blocks on rename

When renaming a file such that a link to another inode is overwritten,
force any delay allocated blocks that to be allocated so that if the
filesystem is mounted with data=ordered, the data blocks will be
pushed out to disk along with the journal commit.  Many application
programs expect this, so we do this to avoid zero length files if the
system crashes unexpectedly.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 6e1ad68cdc7afea47f186824d574d059e1ce0e1e..eb20246c89654758f078867ad929b1a5c590b495 100644 (file)
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2357,7 +2357,7 @@ static int ext4_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 ext4_dir_entry_2 *old_de, *new_de;
-       int retval;
+       int retval, force_da_alloc = 0;
 
        old_bh = new_bh = dir_bh = NULL;
 
@@ -2497,6 +2497,7 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
                ext4_mark_inode_dirty(handle, new_inode);
                if (!new_inode->i_nlink)
                        ext4_orphan_add(handle, new_inode);
+               force_da_alloc = 1;
        }
        retval = 0;
 
@@ -2505,6 +2506,8 @@ end_rename:
        brelse(old_bh);
        brelse(new_bh);
        ext4_journal_stop(handle);
+       if (retval == 0 && force_da_alloc)
+               ext4_alloc_da_blocks(old_inode);
        return retval;
 }