[PATCH v3 08/13] vfs: make vfs_symlink break delegations on parent dir
From: Jeff Layton <jlayton@kernel.org>
Date: 2025-10-21 15:26:29
Also in:
linux-cifs, linux-fsdevel, linux-nfs, linux-unionfs, linux-xfs, lkml, netfs
Subsystem:
ecrypt file system, filesystems (vfs and infrastructure), kernel nfsd, sunrpc, and lockd servers, overlay filesystem, the rest · Maintainers:
Tyler Hicks, Alexander Viro, Christian Brauner, Chuck Lever, Jeff Layton, Miklos Szeredi, Amir Goldstein, Linus Torvalds
In order to add directory delegation support, we must break delegations on the parent on any change to the directory. Add a delegated_inode parameter to vfs_symlink() and have it break the delegation. do_symlinkat() can then wait on the delegation break before proceeding. Signed-off-by: Jeff Layton <jlayton@kernel.org> --- fs/ecryptfs/inode.c | 2 +- fs/init.c | 2 +- fs/namei.c | 16 ++++++++++++++-- fs/nfsd/vfs.c | 2 +- fs/overlayfs/overlayfs.h | 2 +- include/linux/fs.h | 2 +- 6 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 639ae42bcd56890d04592f7269e4ffc099b44f09..d430ec5a63094ea4cd42828e7d44f0f8d918fcec 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c@@ -480,7 +480,7 @@ static int ecryptfs_symlink(struct mnt_idmap *idmap, if (rc) goto out_lock; rc = vfs_symlink(&nop_mnt_idmap, lower_dir, lower_dentry, - encoded_symname); + encoded_symname, NULL); kfree(encoded_symname); if (rc || d_really_is_negative(lower_dentry)) goto out_lock;
diff --git a/fs/init.c b/fs/init.c
index 4f02260dd65b0dfcbfbf5812d2ec6a33444a3b1f..e0f5429c0a49d046bd3f231a260954ed0f90ef44 100644
--- a/fs/init.c
+++ b/fs/init.c@@ -209,7 +209,7 @@ int __init init_symlink(const char *oldname, const char *newname) error = security_path_symlink(&path, dentry, oldname); if (!error) error = vfs_symlink(mnt_idmap(path.mnt), path.dentry->d_inode, - dentry, oldname); + dentry, oldname, NULL); end_creating_path(&path, dentry); return error; }
diff --git a/fs/namei.c b/fs/namei.c
index 7e400cbdbc6af1c72eb684f051d0571e944a27d7..71af256cdd941e200389570538f64a3f795e6c83 100644
--- a/fs/namei.c
+++ b/fs/namei.c@@ -4851,6 +4851,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname) * @dir: inode of the parent directory * @dentry: dentry of the child symlink file * @oldname: name of the file to link to + * @delegated_inode: returns victim inode, if the inode is delegated. * * Create a symlink. *
@@ -4861,7 +4862,8 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname) * raw inode simply pass @nop_mnt_idmap. */ int vfs_symlink(struct mnt_idmap *idmap, struct inode *dir, - struct dentry *dentry, const char *oldname) + struct dentry *dentry, const char *oldname, + struct inode **delegated_inode) { int error;
@@ -4876,6 +4878,10 @@ int vfs_symlink(struct mnt_idmap *idmap, struct inode *dir, if (error) return error; + error = try_break_deleg(dir, delegated_inode); + if (error) + return error; + error = dir->i_op->symlink(idmap, dir, dentry, oldname); if (!error) fsnotify_create(dir, dentry);
@@ -4889,6 +4895,7 @@ int do_symlinkat(struct filename *from, int newdfd, struct filename *to) struct dentry *dentry; struct path path; unsigned int lookup_flags = 0; + struct inode *delegated_inode = NULL; if (IS_ERR(from)) { error = PTR_ERR(from);
@@ -4903,8 +4910,13 @@ int do_symlinkat(struct filename *from, int newdfd, struct filename *to) error = security_path_symlink(&path, dentry, from->name); if (!error) error = vfs_symlink(mnt_idmap(path.mnt), path.dentry->d_inode, - dentry, from->name); + dentry, from->name, &delegated_inode); end_creating_path(&path, dentry); + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry; + } if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry;
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 44debf3d0be450ddc245e2fa4f57fe076e1454a2..386f454badce7ed448399ef93e9c8edafbcc4d79 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c@@ -1829,7 +1829,7 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, err = fh_fill_pre_attrs(fhp); if (err != nfs_ok) goto out_unlock; - host_err = vfs_symlink(&nop_mnt_idmap, d_inode(dentry), dnew, path); + host_err = vfs_symlink(&nop_mnt_idmap, d_inode(dentry), dnew, path, NULL); err = nfserrno(host_err); cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp); if (!err)
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 87b82dada7ec1b8429299c68078cda24176c5607..94bb4540f7ae2e0571b3b88393c180bd73c3c09c 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h@@ -267,7 +267,7 @@ static inline int ovl_do_symlink(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry, const char *oldname) { - int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname); + int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname, NULL); pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); return err;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a1e1afe39e01a46bf0a81e241b92690947402851..d8c7245da3bf3200b435c7ea6cafcf7903ebf293 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -2117,7 +2117,7 @@ struct dentry *vfs_mkdir(struct mnt_idmap *, struct inode *, int vfs_mknod(struct mnt_idmap *, struct inode *, struct dentry *, umode_t, dev_t, struct inode **); int vfs_symlink(struct mnt_idmap *, struct inode *, - struct dentry *, const char *); + struct dentry *, const char *, struct inode **); int vfs_link(struct dentry *, struct mnt_idmap *, struct inode *, struct dentry *, struct inode **); int vfs_rmdir(struct mnt_idmap *, struct inode *, struct dentry *,
--
2.51.0