[PATCH stable/linux-5.10.y 1/7] ovl: pass layer mnt to ovl_open_realfile()
From: Cai Xinchen <hidden>
Date: 2026-06-29 06:38:55
Also in:
bpf, linux-fsdevel, linux-unionfs, lkml, selinux, stable
Subsystem:
filesystems (vfs and infrastructure), overlay filesystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Miklos Szeredi, Amir Goldstein, Linus Torvalds
From: Amir Goldstein <amir73il@gmail.com> [ Upstream commit 1248ea4b91bcdafefdb025087e67d58382cfc9eb ] Ensure that ovl_open_realfile() takes the mount's idmapping into account. We add a new helper ovl_path_realdata() that can be used to easily retrieve the relevant path which we can pass down. This is needed to support idmapped base layers with overlay. Cc: <redacted> Tested-by: Giuseppe Scrivano <redacted> Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Miklos Szeredi <redacted> Signed-off-by: Cai Xinchen <redacted> --- fs/overlayfs/file.c | 22 +++++++++++++--------- fs/overlayfs/overlayfs.h | 1 + fs/overlayfs/util.c | 14 ++++++++++++++ 3 files changed, 28 insertions(+), 9 deletions(-)
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 4440ff43cb66..343db8b3ecd6 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c@@ -37,8 +37,9 @@ static char ovl_whatisit(struct inode *inode, struct inode *realinode) #define OVL_OPEN_FLAGS (O_NOATIME | FMODE_NONOTIFY) static struct file *ovl_open_realfile(const struct file *file, - struct inode *realinode) + struct path *realpath) { + struct inode *realinode = d_inode(realpath->dentry); struct inode *inode = file_inode(file); struct file *realfile; const struct cred *old_cred;
@@ -103,21 +104,21 @@ static int ovl_change_flags(struct file *file, unsigned int flags) static int ovl_real_fdget_meta(const struct file *file, struct fd *real, bool allow_meta) { - struct inode *inode = file_inode(file); - struct inode *realinode; + struct dentry *dentry = file_dentry(file); + struct path realpath; real->flags = 0; real->file = file->private_data; if (allow_meta) - realinode = ovl_inode_real(inode); + ovl_path_real(dentry, &realpath); else - realinode = ovl_inode_realdata(inode); + ovl_path_realdata(dentry, &realpath); /* Has it been copied up since we'd opened it? */ - if (unlikely(file_inode(real->file) != realinode)) { + if (unlikely(file_inode(real->file) != d_inode(realpath.dentry))) { real->flags = FDPUT_FPUT; - real->file = ovl_open_realfile(file, realinode); + real->file = ovl_open_realfile(file, &realpath); return PTR_ERR_OR_ZERO(real->file); }
@@ -143,17 +144,20 @@ static int ovl_real_fdget(const struct file *file, struct fd *real) static int ovl_open(struct inode *inode, struct file *file) { + struct dentry *dentry = file_dentry(file); struct file *realfile; + struct path realpath; int err; - err = ovl_maybe_copy_up(file_dentry(file), file->f_flags); + err = ovl_maybe_copy_up(dentry, file->f_flags); if (err) return err; /* No longer need these flags, so don't pass them on to underlying fs */ file->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); - realfile = ovl_open_realfile(file, ovl_inode_realdata(inode)); + ovl_path_realdata(dentry, &realpath); + realfile = ovl_open_realfile(file, &realpath); if (IS_ERR(realfile)) return PTR_ERR(realfile);
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 5ac968f709a4..5b8a1c9bc355 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h@@ -274,6 +274,7 @@ void ovl_path_upper(struct dentry *dentry, struct path *path); void ovl_path_lower(struct dentry *dentry, struct path *path); void ovl_path_lowerdata(struct dentry *dentry, struct path *path); enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); +enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path); struct dentry *ovl_dentry_upper(struct dentry *dentry); struct dentry *ovl_dentry_lower(struct dentry *dentry); struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 26f29a3e5ada..431dfe3db0cc 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c@@ -209,6 +209,20 @@ enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) return type; } +enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path) +{ + enum ovl_path_type type = ovl_path_type(dentry); + + WARN_ON_ONCE(d_is_dir(dentry)); + + if (!OVL_TYPE_UPPER(type) || OVL_TYPE_MERGE(type)) + ovl_path_lowerdata(dentry, path); + else + ovl_path_upper(dentry, path); + + return type; +} + struct dentry *ovl_dentry_upper(struct dentry *dentry) { struct inode *inode = d_inode(dentry);
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2.18.0.huawei.25