[PATCH v2 07/11] vfs: make vfs_mknod break delegations on parent directory
From: Jeff Layton <jlayton@kernel.org>
Date: 2025-10-17 11:32:46
Also in:
linux-cifs, linux-fsdevel, linux-nfs, linux-unionfs, linux-xfs, lkml, netfs
Subsystem:
driver core, kobjects, debugfs and sysfs, ecrypt file system, filesystems (vfs and infrastructure), kernel nfsd, sunrpc, and lockd servers, networking [general], networking [unix sockets], overlay filesystem, the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Tyler Hicks, Alexander Viro, Christian Brauner, Chuck Lever, Jeff Layton, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Miklos Szeredi, Amir Goldstein, 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 new delegated_inode return pointer to vfs_mknod() and have the appropriate callers wait when there is an outstanding delegation. All other callers just set the pointer to NULL. Signed-off-by: Jeff Layton <jlayton@kernel.org> --- drivers/base/devtmpfs.c | 2 +- fs/ecryptfs/inode.c | 2 +- fs/init.c | 2 +- fs/namei.c | 25 +++++++++++++++++-------- fs/nfsd/vfs.c | 2 +- fs/overlayfs/overlayfs.h | 2 +- include/linux/fs.h | 4 ++-- net/unix/af_unix.c | 2 +- 8 files changed, 25 insertions(+), 16 deletions(-)
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 104025104ef75381984fd94dfbd50feeaa8cdd22..2f576ecf18324f767cd5ac6cbd28adbf9f46b958 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c@@ -231,7 +231,7 @@ static int handle_create(const char *nodename, umode_t mode, kuid_t uid, return PTR_ERR(dentry); err = vfs_mknod(&nop_mnt_idmap, d_inode(path.dentry), dentry, mode, - dev->devt); + dev->devt, NULL); if (!err) { struct iattr newattrs;
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 661709b157ce854c3bfdfdb13f7c10435fad9756..639ae42bcd56890d04592f7269e4ffc099b44f09 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c@@ -565,7 +565,7 @@ ecryptfs_mknod(struct mnt_idmap *idmap, struct inode *dir, rc = lock_parent(dentry, &lower_dentry, &lower_dir); if (!rc) rc = vfs_mknod(&nop_mnt_idmap, lower_dir, - lower_dentry, mode, dev); + lower_dentry, mode, dev, NULL); if (rc || d_really_is_negative(lower_dentry)) goto out; rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
diff --git a/fs/init.c b/fs/init.c
index 895f8a09a71acfd03e11164e3b441a7d4e2de146..4f02260dd65b0dfcbfbf5812d2ec6a33444a3b1f 100644
--- a/fs/init.c
+++ b/fs/init.c@@ -157,7 +157,7 @@ int __init init_mknod(const char *filename, umode_t mode, unsigned int dev) error = security_path_mknod(&path, dentry, mode, dev); if (!error) error = vfs_mknod(mnt_idmap(path.mnt), path.dentry->d_inode, - dentry, mode, new_decode_dev(dev)); + dentry, mode, new_decode_dev(dev), NULL); end_creating_path(&path, dentry); return error; }
diff --git a/fs/namei.c b/fs/namei.c
index 7510942e0249de19df4363b92f813b3acdfc2254..7e400cbdbc6af1c72eb684f051d0571e944a27d7 100644
--- a/fs/namei.c
+++ b/fs/namei.c@@ -4297,13 +4297,15 @@ inline struct dentry *start_creating_user_path( } EXPORT_SYMBOL(start_creating_user_path); + /** * vfs_mknod - create device node or file - * @idmap: idmap of the mount the inode was found from - * @dir: inode of the parent directory - * @dentry: dentry of the child device node - * @mode: mode of the child device node - * @dev: device number of device to create + * @idmap: idmap of the mount the inode was found from + * @dir: inode of the parent directory + * @dentry: dentry of the child device node + * @mode: mode of the child device node + * @dev: device number of device to create + * @delegated_inode: returns parent inode, if the inode is delegated. * * Create a device node or file. *
@@ -4314,7 +4316,8 @@ EXPORT_SYMBOL(start_creating_user_path); * raw inode simply pass @nop_mnt_idmap. */ int vfs_mknod(struct mnt_idmap *idmap, struct inode *dir, - struct dentry *dentry, umode_t mode, dev_t dev) + struct dentry *dentry, umode_t mode, dev_t dev, + struct inode **delegated_inode) { bool is_whiteout = S_ISCHR(mode) && dev == WHITEOUT_DEV; int error = may_create(idmap, dir, dentry);
@@ -4338,6 +4341,10 @@ int vfs_mknod(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->mknod(idmap, dir, dentry, mode, dev); if (!error) fsnotify_create(dir, dentry);
@@ -4397,11 +4404,13 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode, break; case S_IFCHR: case S_IFBLK: error = vfs_mknod(idmap, path.dentry->d_inode, - dentry, mode, new_decode_dev(dev)); + dentry, mode, new_decode_dev(dev), + &delegated_inode); break; case S_IFIFO: case S_IFSOCK: error = vfs_mknod(idmap, path.dentry->d_inode, - dentry, mode, 0); + dentry, mode, 0, + &delegated_inode); break; } out2:
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 8834bc59f5cfcc88797eb09189b6c12d29e98d10..eeb138569eba5df6de361cf6ba29604722e14af9 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c@@ -1659,7 +1659,7 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, case S_IFIFO: case S_IFSOCK: host_err = vfs_mknod(&nop_mnt_idmap, dirp, dchild, - iap->ia_mode, rdev); + iap->ia_mode, rdev, NULL); break; default: printk(KERN_WARNING "nfsd: bad file type %o in nfsd_create\n",
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index d3123f5d97e86b58e4c9608cf6ef2abd1fcddbcd..87b82dada7ec1b8429299c68078cda24176c5607 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h@@ -257,7 +257,7 @@ static inline int ovl_do_mknod(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) { - int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev); + int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev, NULL); pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); return err;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5fcf64d9cf42ce135c0fbcbf6dfbf8816ae0bcb1..a1e1afe39e01a46bf0a81e241b92690947402851 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -2115,7 +2115,7 @@ int vfs_create(struct mnt_idmap *, struct inode *, struct dentry *vfs_mkdir(struct mnt_idmap *, struct inode *, struct dentry *, umode_t, struct inode **); int vfs_mknod(struct mnt_idmap *, struct inode *, struct dentry *, - umode_t, dev_t); + umode_t, dev_t, struct inode **); int vfs_symlink(struct mnt_idmap *, struct inode *, struct dentry *, const char *); int vfs_link(struct dentry *, struct mnt_idmap *, struct inode *,
@@ -2151,7 +2151,7 @@ static inline int vfs_whiteout(struct mnt_idmap *idmap, struct inode *dir, struct dentry *dentry) { return vfs_mknod(idmap, dir, dentry, S_IFCHR | WHITEOUT_MODE, - WHITEOUT_DEV); + WHITEOUT_DEV, NULL); } struct file *kernel_tmpfile_open(struct mnt_idmap *idmap,
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 768098dec2310008632558ae928703b37c3cc8ef..db1fd8d6a84c2c7c0d45b43d9c5a936b3d491b7b 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c@@ -1399,7 +1399,7 @@ static int unix_bind_bsd(struct sock *sk, struct sockaddr_un *sunaddr, idmap = mnt_idmap(parent.mnt); err = security_path_mknod(&parent, dentry, mode, 0); if (!err) - err = vfs_mknod(idmap, d_inode(parent.dentry), dentry, mode, 0); + err = vfs_mknod(idmap, d_inode(parent.dentry), dentry, mode, 0, NULL); if (err) goto out_path; err = mutex_lock_interruptible(&u->bindlock);
--
2.51.0