[PATCH v7 28/49] vfs: fix linkat to retry on ESTALE errors

Jeff Layton
2012-10-02T00:17:46Z

fs/namei.c | 46 ++++++++++++++++++++++++++--------------------
1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index fb9d36f..e0ee4b9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3616,6 +3616,7 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
struct path old_path, new_path;
int how = 0;
int error;
+ unsigned int try = 0;

if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0)
return -EINVAL;
@@ -3633,30 +3634,35 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
if (flags & AT_SYMLINK_FOLLOW)
how |= LOOKUP_FOLLOW;

- error = user_path_at(olddfd, oldname, how, &old_path);
- if (error)
- return error;
+ do {
+ error = user_path_at(olddfd, oldname, how, &old_path);
+ if (error)
+ break;

- new_dentry = user_path_create(newdfd, newname, &new_path, false, false);
- error = PTR_ERR(new_dentry);
- if (IS_ERR(new_dentry))
- goto out;
+ new_dentry = user_path_create(newdfd, newname, &new_path,
+ false, false);
+ error = PTR_ERR(new_dentry);
+ if (IS_ERR(new_dentry))
+ goto out;

- error = -EXDEV;
- if (old_path.mnt != new_path.mnt)
- goto out_dput;
- error = may_linkat(&old_path);
- if (unlikely(error))
- goto out_dput;
- error = security_path_link(old_path.dentry, &new_path, new_dentry);
- if (error)
- goto out_dput;
- error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry);
+ error = -EXDEV;
+ if (old_path.mnt != new_path.mnt)
+ goto out_dput;
+ error = may_linkat(&old_path);
+ if (unlikely(error))
+ goto out_dput;
+ error = security_path_link(old_path.dentry, &new_path,
+ new_dentry);
+ if (error)
+ goto out_dput;
+ error = vfs_link(old_path.dentry, new_path.dentry->d_inode,
+ new_dentry);
out_dput:
- done_path_create(&new_path, new_dentry);
+ done_path_create(&new_path, new_dentry);
out:
- path_put(&old_path);
-
+ path_put(&old_path);
+ how |= LOOKUP_REVAL;
+ } while (retry_estale(error, try++));
return error;
}

--
1.7.11.4