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authorAmir Goldstein <amir73il@gmail.com>2022-04-04 13:51:47 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2022-04-28 17:31:11 +0300
commit1248ea4b91bcdafefdb025087e67d58382cfc9eb (patch)
treeb2cdefa0cfc7da672d6e39ce956bea16f0efd8ec /fs/overlayfs
parent5272eaf3a5682750f6f26ec542b206f0821fb3cb (diff)
downloadlinux-1248ea4b91bcdafefdb025087e67d58382cfc9eb.tar.xz
ovl: pass layer mnt to ovl_open_realfile()
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: <linux-unionfs@vger.kernel.org> Tested-by: Giuseppe Scrivano <gscrivan@redhat.com> 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 <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/file.c22
-rw-r--r--fs/overlayfs/overlayfs.h1
-rw-r--r--fs/overlayfs/util.c14
3 files changed, 28 insertions, 9 deletions
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index fa125feed0ff..9250e04e97af 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -38,8 +38,9 @@ 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;
@@ -104,21 +105,21 @@ 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);
}
@@ -144,17 +145,20 @@ 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 40bf3d184bdb..d6405c2046ed 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -320,6 +320,7 @@ 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 5a7e5d1e884b..42293610f64e 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -194,6 +194,20 @@ 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)
{
return ovl_upperdentry_dereference(OVL_I(d_inode(dentry)));