Commit 1248ea4b authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
Browse files

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: default avatarGiuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 5272eaf3

fs/overlayfs/file.c

+13 −9
Original line number Diff line number Diff line
@@ -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);

fs/overlayfs/overlayfs.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

fs/overlayfs/util.c

+14 −0
Original line number Diff line number Diff line
@@ -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)));