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Message-Id: <20251021-dir-deleg-ro-v3-8-a08b1cde9f4c@kernel.org>
Date: Tue, 21 Oct 2025 11:25:43 -0400
From: Jeff Layton <jlayton@...nel.org>
To: Miklos Szeredi <miklos@...redi.hu>,
Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
Chuck Lever <chuck.lever@...cle.com>,
Alexander Aring <alex.aring@...il.com>,
Trond Myklebust <trondmy@...nel.org>, Anna Schumaker <anna@...nel.org>,
Steve French <sfrench@...ba.org>, Paulo Alcantara <pc@...guebit.org>,
Ronnie Sahlberg <ronniesahlberg@...il.com>,
Shyam Prasad N <sprasad@...rosoft.com>, Tom Talpey <tom@...pey.com>,
Bharath SM <bharathsm@...rosoft.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>, Danilo Krummrich <dakr@...nel.org>,
David Howells <dhowells@...hat.com>, Tyler Hicks <code@...icks.com>,
NeilBrown <neil@...wn.name>, Olga Kornievskaia <okorniev@...hat.com>,
Dai Ngo <Dai.Ngo@...cle.com>, Amir Goldstein <amir73il@...il.com>,
Namjae Jeon <linkinjeon@...nel.org>, Steve French <smfrench@...il.com>,
Sergey Senozhatsky <senozhatsky@...omium.org>,
Carlos Maiolino <cem@...nel.org>, Kuniyuki Iwashima <kuniyu@...gle.com>,
"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
Simon Horman <horms@...nel.org>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-nfs@...r.kernel.org, linux-cifs@...r.kernel.org,
samba-technical@...ts.samba.org, netfs@...ts.linux.dev,
ecryptfs@...r.kernel.org, linux-unionfs@...r.kernel.org,
linux-xfs@...r.kernel.org, netdev@...r.kernel.org,
Jeff Layton <jlayton@...nel.org>
Subject: [PATCH v3 08/13] vfs: make vfs_symlink break delegations on parent
dir
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@...nel.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
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