locks: break delegations on rename
Cc: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namei.c b/fs/namei.c
index cfaeaae..ce7e580 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4022,7 +4022,8 @@
}
static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry,
- struct inode *new_dir, struct dentry *new_dentry)
+ struct inode *new_dir, struct dentry *new_dentry,
+ struct inode **delegated_inode)
{
struct inode *target = new_dentry->d_inode;
struct inode *source = old_dentry->d_inode;
@@ -4039,6 +4040,14 @@
if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
goto out;
+ error = try_break_deleg(source, delegated_inode);
+ if (error)
+ goto out;
+ if (target) {
+ error = try_break_deleg(target, delegated_inode);
+ if (error)
+ goto out;
+ }
error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
if (error)
goto out;
@@ -4053,8 +4062,30 @@
return error;
}
+/**
+ * vfs_rename - rename a filesystem object
+ * @old_dir: parent of source
+ * @old_dentry: source
+ * @new_dir: parent of destination
+ * @new_dentry: destination
+ * @delegated_inode: returns an inode needing a delegation break
+ *
+ * The caller must hold multiple mutexes--see lock_rename()).
+ *
+ * If vfs_rename discovers a delegation in need of breaking at either
+ * the source or destination, it will return -EWOULDBLOCK and return a
+ * reference to the inode in delegated_inode. The caller should then
+ * break the delegation and retry. Because breaking a delegation may
+ * take a long time, the caller should drop all locks before doing
+ * so.
+ *
+ * Alternatively, a caller may pass NULL for delegated_inode. This may
+ * be appropriate for callers that expect the underlying filesystem not
+ * to be NFS exported.
+ */
int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
- struct inode *new_dir, struct dentry *new_dentry)
+ struct inode *new_dir, struct dentry *new_dentry,
+ struct inode **delegated_inode)
{
int error;
int is_dir = d_is_directory(old_dentry) || d_is_autodir(old_dentry);
@@ -4082,7 +4113,7 @@
if (is_dir)
error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry);
else
- error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry);
+ error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry,delegated_inode);
if (!error)
fsnotify_move(old_dir, new_dir, old_name, is_dir,
new_dentry->d_inode, old_dentry);
@@ -4098,6 +4129,7 @@
struct dentry *old_dentry, *new_dentry;
struct dentry *trap;
struct nameidata oldnd, newnd;
+ struct inode *delegated_inode = NULL;
struct filename *from;
struct filename *to;
unsigned int lookup_flags = 0;
@@ -4137,6 +4169,7 @@
newnd.flags &= ~LOOKUP_PARENT;
newnd.flags |= LOOKUP_RENAME_TARGET;
+retry_deleg:
trap = lock_rename(new_dir, old_dir);
old_dentry = lookup_hash(&oldnd);
@@ -4173,13 +4206,19 @@
if (error)
goto exit5;
error = vfs_rename(old_dir->d_inode, old_dentry,
- new_dir->d_inode, new_dentry);
+ new_dir->d_inode, new_dentry,
+ &delegated_inode);
exit5:
dput(new_dentry);
exit4:
dput(old_dentry);
exit3:
unlock_rename(new_dir, old_dir);
+ if (delegated_inode) {
+ error = break_deleg_wait(&delegated_inode);
+ if (!error)
+ goto retry_deleg;
+ }
mnt_drop_write(oldnd.path.mnt);
exit2:
if (retry_estale(error, lookup_flags))