[PATCH 03/16] Unionfs: Retry lookup for different silly-renamed files

[Josef 'Jeff' Sipek]

From: Erez Zadok <ezk@xxxxxxxxxxxxx>

When we have to copyup an open-but-unlinked file, we have to give it a
temporary name, similar to NFS's silly-renamed files.  So we generate
temporary file names until we find one that doesn't exist, and use it.  The
code had a bug where if the silly-renamed file name already existed, Unionfs
would oops upon copyup to that temp name.

Signed-off-by: Erez Zadok <ezk@xxxxxxxxxxxxx>
Signed-off-by: Josef 'Jeff' Sipek <jsipek@xxxxxxxxxxxxx>
---
 fs/unionfs/commonfops.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
index 89a236b..28635d8 100644
--- a/fs/unionfs/commonfops.c
+++ b/fs/unionfs/commonfops.c
@@ -42,6 +42,7 @@ static int copyup_deleted_file(struct file *file, struct dentry *dentry,
 	sprintf(name, ".unionfs%*.*lx",
 		i_inosize, i_inosize, hidden_dentry->d_inode->i_ino);
 
+retry:
 	/*
 	 * Loop, looking for an unused temp name to copyup to.
 	 *
@@ -68,13 +69,14 @@ static int copyup_deleted_file(struct file *file, struct dentry *dentry,
 			err = PTR_ERR(tmp_dentry);
 			goto out;
 		}
-		/* don't dput here because of do-while condition eval order */
 	} while (tmp_dentry->d_inode != NULL);	/* need negative dentry */
 	dput(tmp_dentry);
 
 	err = copyup_named_file(dentry->d_parent->d_inode, file, name, bstart,
 				bindex, file->f_dentry->d_inode->i_size);
-	if (err)
+	if (err == -EEXIST)
+		goto retry;
+	else if (err)
 		goto out;
 
 	/* bring it to the same state as an unlinked file */
-- 
1.5.2.rc1.165.gaf9b

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