[PATCH v5 12/17] vfs: make vfs_symlink break delegations on parent dir
From: Jeff Layton <jlayton@kernel.org>
Date: 2025-11-05 16:54:50
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. Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: NeilBrown <neil@brown.name> 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 83f06452476dec4025cc8f50e082ae6ccbbc7914..ba15e7359dfa6e150b577205991010873a633511 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c@@ -479,7 +479,7 @@ 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 e9616134390fb7f0d09a759be69bf677f8800bc5..d5ab28947b2b6c6e19c7bb4a9140ccec407dc07c 100644
--- a/fs/namei.c
+++ b/fs/namei.c@@ -4845,6 +4845,7 @@ 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. *
@@ -4855,7 +4856,8 @@ 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 delegated_inode *delegated_inode) { int error;
@@ -4870,6 +4872,10 @@ 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);
@@ -4883,6 +4889,7 @@ int do_symlinkat(struct filename *from, int newdfd, struct filename *to) struct dentry *dentry; struct path path; unsigned int lookup_flags = 0; + struct delegated_inode delegated_inode = { }; if (IS_ERR(from)) { error = PTR_ERR(from);
@@ -4897,8 +4904,13 @@ 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 (is_delegated(&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 6684935007b17ed40723ff0a744045fd187ace5e..28710da4cce7cc7fc1e14d29420239dc357316f6 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c@@ -1742,7 +1742,7 @@ 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 afd95721f76ea761cfe7133c3902028550f3e359..5065961bd370628c9afe914ea570d9998a096660 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 1a5d86cfafaa97fc89d15cd1a156968b8c3dd377..64323e618724bc20dc101db13035b042f5f88e4d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -2118,7 +2118,7 @@ struct dentry *vfs_mkdir(struct mnt_idmap *, struct inode *, int vfs_mknod(struct mnt_idmap *, struct inode *, struct dentry *, umode_t, dev_t, struct delegated_inode *); int vfs_symlink(struct mnt_idmap *, struct inode *, - struct dentry *, const char *); + struct dentry *, const char *, struct delegated_inode *); int vfs_link(struct dentry *, struct mnt_idmap *, struct inode *, struct dentry *, struct delegated_inode *); int vfs_rmdir(struct mnt_idmap *, struct inode *, struct dentry *,
--
2.51.1