[PATCH v3 06/38] vfs: break parent dir delegations in open(..., O_CREAT) codepath
From: Jeff Layton <jlayton@kernel.org>
Date: 2025-09-24 18:06:35
Also in:
linux-cifs, linux-doc, linux-fsdevel, linux-nfs, linux-unionfs, linux-xfs, lkml, 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. 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 4e058b00208c1663ba828c6f8ed1f82c26a4f136..903b70a82530938a0fdf10508529a1b7cc38136d 100644
--- a/fs/namei.c
+++ b/fs/namei.c@@ -3609,7 +3609,7 @@ 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 inode **delegated_inode) { struct mnt_idmap *idmap; struct dentry *dir = nd->path.dentry;
@@ -3698,6 +3698,11 @@ 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) {
@@ -3761,6 +3766,7 @@ static const char *open_last_lookups(struct nameidata *nd, struct file *file, const struct open_flags *op) { struct dentry *dir = nd->path.dentry; + struct inode *delegated_inode = NULL; int open_flag = op->open_flag; bool got_write = false; struct dentry *dentry;
@@ -3791,7 +3797,7 @@ 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); /*
@@ -3804,7 +3810,7 @@ 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);
@@ -3819,8 +3825,16 @@ 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 (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);
--
2.51.0