Unverified Commit 7a80e5b8 authored by Giuseppe Scrivano's avatar Giuseppe Scrivano Committed by Christian Brauner (Microsoft)
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shmem: support idmapped mounts for tmpfs 



This patch enables idmapped mounts for tmpfs when CONFIG_SHMEM is defined.
Since all dedicated helpers for this functionality exist, in this
patch we just pass down the idmap argument from the VFS methods to the
relevant helpers.

Signed-off-by: default avatarGiuseppe Scrivano <gscrivan@redhat.com>
Tested-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: default avatarSeth Forshee (DigitalOcean) <sforshee@kernel.org>
Signed-off-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
parent 3707d84c

mm/shmem.c

+28 −19
Original line number Diff line number Diff line
@@ -1068,7 +1068,7 @@ static int shmem_getattr(struct mnt_idmap *idmap, 
	stat->attributes_mask |= (STATX_ATTR_APPEND |

			STATX_ATTR_IMMUTABLE |

			STATX_ATTR_NODUMP);

	generic_fillattr(&nop_mnt_idmap, inode, stat);

	generic_fillattr(idmap, inode, stat);



	if (shmem_is_huge(NULL, inode, 0, false))

		stat->blksize = HPAGE_PMD_SIZE;
@@ -1091,7 +1091,7 @@ static int shmem_setattr(struct mnt_idmap *idmap, 
	bool update_mtime = false;

	bool update_ctime = true;



	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);

	error = setattr_prepare(idmap, dentry, attr);

	if (error)

		return error;
@@ -1129,9 +1129,9 @@ static int shmem_setattr(struct mnt_idmap *idmap, 
		}

	}



	setattr_copy(&nop_mnt_idmap, inode, attr);

	setattr_copy(idmap, inode, attr);

	if (attr->ia_valid & ATTR_MODE)

		error = posix_acl_chmod(&nop_mnt_idmap, dentry, inode->i_mode);

		error = posix_acl_chmod(idmap, dentry, inode->i_mode);

	if (!error && update_ctime) {

		inode->i_ctime = current_time(inode);

		if (update_mtime)
@@ -2329,8 +2329,9 @@ static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags) 
#define shmem_initxattrs NULL

#endif



static struct inode *shmem_get_inode(struct super_block *sb, struct inode *dir,

				     umode_t mode, dev_t dev, unsigned long flags)

static struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block *sb,

				     struct inode *dir, umode_t mode, dev_t dev,

				     unsigned long flags)

{

	struct inode *inode;

	struct shmem_inode_info *info;
@@ -2343,7 +2344,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, struct inode *dir, 
	inode = new_inode(sb);

	if (inode) {

		inode->i_ino = ino;

		inode_init_owner(&nop_mnt_idmap, inode, dir, mode);

		inode_init_owner(idmap, inode, dir, mode);

		inode->i_blocks = 0;

		inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);

		inode->i_generation = get_random_u32();
@@ -2921,7 +2922,7 @@ shmem_mknod(struct mnt_idmap *idmap, struct inode *dir, 
	struct inode *inode;

	int error = -ENOSPC;



	inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE);

	inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, dev, VM_NORESERVE);

	if (inode) {

		error = simple_acl_create(dir, inode);

		if (error)
@@ -2952,7 +2953,7 @@ shmem_tmpfile(struct mnt_idmap *idmap, struct inode *dir, 
	struct inode *inode;

	int error = -ENOSPC;



	inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE);

	inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, 0, VM_NORESERVE);

	if (inode) {

		error = security_inode_init_security(inode, dir,

						     NULL,
@@ -2975,8 +2976,8 @@ static int shmem_mkdir(struct mnt_idmap *idmap, struct inode *dir, 
{

	int error;



	if ((error = shmem_mknod(&nop_mnt_idmap, dir, dentry,

				 mode | S_IFDIR, 0)))

	error = shmem_mknod(idmap, dir, dentry, mode | S_IFDIR, 0);

	if (error)

		return error;

	inc_nlink(dir);

	return 0;
@@ -2985,7 +2986,7 @@ static int shmem_mkdir(struct mnt_idmap *idmap, struct inode *dir, 
static int shmem_create(struct mnt_idmap *idmap, struct inode *dir,

			struct dentry *dentry, umode_t mode, bool excl)

{

	return shmem_mknod(&nop_mnt_idmap, dir, dentry, mode | S_IFREG, 0);

	return shmem_mknod(idmap, dir, dentry, mode | S_IFREG, 0);

}



/*
@@ -3055,7 +3056,7 @@ static int shmem_whiteout(struct mnt_idmap *idmap, 
	if (!whiteout)

		return -ENOMEM;



	error = shmem_mknod(&nop_mnt_idmap, old_dir, whiteout,

	error = shmem_mknod(idmap, old_dir, whiteout,

			    S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV);

	dput(whiteout);

	if (error)
@@ -3098,7 +3099,7 @@ static int shmem_rename2(struct mnt_idmap *idmap, 
	if (flags & RENAME_WHITEOUT) {

		int error;



		error = shmem_whiteout(&nop_mnt_idmap, old_dir, old_dentry);

		error = shmem_whiteout(idmap, old_dir, old_dentry);

		if (error)

			return error;

	}
@@ -3136,7 +3137,7 @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir, 
	if (len > PAGE_SIZE)

		return -ENAMETOOLONG;



	inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK | 0777, 0,

	inode = shmem_get_inode(idmap, dir->i_sb, dir, S_IFLNK | 0777, 0,

				VM_NORESERVE);

	if (!inode)

		return -ENOSPC;
@@ -3819,7 +3820,8 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) 
#endif

	uuid_gen(&sb->s_uuid);



	inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE);

	inode = shmem_get_inode(&nop_mnt_idmap, sb, NULL, S_IFDIR | sbinfo->mode, 0,

				VM_NORESERVE);

	if (!inode)

		goto failed;

	inode->i_uid = sbinfo->uid;
@@ -4044,7 +4046,11 @@ static struct file_system_type shmem_fs_type = { 
	.parameters	= shmem_fs_parameters,

#endif

	.kill_sb	= kill_litter_super,

#ifdef CONFIG_SHMEM

	.fs_flags	= FS_USERNS_MOUNT | FS_ALLOW_IDMAP,

#else

	.fs_flags	= FS_USERNS_MOUNT,

#endif

};



void __init shmem_init(void)
@@ -4196,7 +4202,7 @@ EXPORT_SYMBOL_GPL(shmem_truncate_range); 
#define shmem_vm_ops				generic_file_vm_ops

#define shmem_anon_vm_ops			generic_file_vm_ops

#define shmem_file_operations			ramfs_file_operations

#define shmem_get_inode(sb, dir, mode, dev, flags)	ramfs_get_inode(sb, dir, mode, dev)

#define shmem_get_inode(idmap, sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)

#define shmem_acct_size(flags, size)		0

#define shmem_unacct_size(flags, size)		do {} while (0)
@@ -4219,8 +4225,11 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, l 
	if (shmem_acct_size(flags, size))

		return ERR_PTR(-ENOMEM);



	inode = shmem_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0,

				flags);

	if (is_idmapped_mnt(mnt))

		return ERR_PTR(-EINVAL);



	inode = shmem_get_inode(&nop_mnt_idmap, mnt->mnt_sb, NULL,

				S_IFREG | S_IRWXUGO, 0, flags);

	if (unlikely(!inode)) {

		shmem_unacct_size(flags, size);

		return ERR_PTR(-ENOSPC);