[PATCH v6 08/17] vfs: break parent dir delegations in open(..., O_CREAT) codepath
From: Jeff Layton <jlayton@kernel.org>
Date: 2025-11-11 14:13:31
Also in:
linux-cifs, linux-fsdevel, linux-nfs, linux-unionfs, linux-xfs, lkml, netdev, netfs
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
In order to add directory delegation support, we need to break delegations on the parent whenever there is going to be a change in the directory. Add a delegated_inode parameter to lookup_open and have it break the delegation. Then, open_last_lookups can wait for the delegation break and retry the call to lookup_open once it's done. Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: NeilBrown <neil@brown.name> Signed-off-by: Jeff Layton <jlayton@kernel.org> --- fs/namei.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 9e0393a92091ac522b5324fcdad8c5592a948e8d..f439429bdfa271ccc64c937771ef4175597feb53 100644
--- a/fs/namei.c
+++ b/fs/namei.c@@ -3697,7 +3697,7 @@ static struct dentry *atomic_open(struct nameidata *nd, struct dentry *dentry, */ static struct dentry *lookup_open(struct nameidata *nd, struct file *file, const struct open_flags *op, - bool got_write) + bool got_write, struct delegated_inode *delegated_inode) { struct mnt_idmap *idmap; struct dentry *dir = nd->path.dentry;
@@ -3786,6 +3786,11 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file, /* Negative dentry, just create the file */ if (!dentry->d_inode && (open_flag & O_CREAT)) { + /* but break the directory lease first! */ + error = try_break_deleg(dir_inode, delegated_inode); + if (error) + goto out_dput; + file->f_mode |= FMODE_CREATED; audit_inode_child(dir_inode, dentry, AUDIT_TYPE_CHILD_CREATE); if (!dir_inode->i_op->create) {
@@ -3848,6 +3853,7 @@ static struct dentry *lookup_fast_for_open(struct nameidata *nd, int open_flag) static const char *open_last_lookups(struct nameidata *nd, struct file *file, const struct open_flags *op) { + struct delegated_inode delegated_inode = { }; struct dentry *dir = nd->path.dentry; int open_flag = op->open_flag; bool got_write = false;
@@ -3879,7 +3885,7 @@ static const char *open_last_lookups(struct nameidata *nd, return ERR_PTR(-ECHILD); } } - +retry: if (open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) { got_write = !mnt_want_write(nd->path.mnt); /*
@@ -3892,7 +3898,7 @@ static const char *open_last_lookups(struct nameidata *nd, inode_lock(dir->d_inode); else inode_lock_shared(dir->d_inode); - dentry = lookup_open(nd, file, op, got_write); + dentry = lookup_open(nd, file, op, got_write, &delegated_inode); if (!IS_ERR(dentry)) { if (file->f_mode & FMODE_CREATED) fsnotify_create(dir->d_inode, dentry);
@@ -3907,8 +3913,16 @@ static const char *open_last_lookups(struct nameidata *nd, if (got_write) mnt_drop_write(nd->path.mnt); - if (IS_ERR(dentry)) + if (IS_ERR(dentry)) { + if (is_delegated(&delegated_inode)) { + int error = break_deleg_wait(&delegated_inode); + + if (!error) + goto retry; + return ERR_PTR(error); + } return ERR_CAST(dentry); + } if (file->f_mode & (FMODE_OPENED | FMODE_CREATED)) { dput(nd->path.dentry);
--
2.51.1