[PATCH] f2fs: support idmapped mounts

From: Chao Yu
Date: Fri Feb 04 2022 - 00:25:09 EST


This patch enables idmapped mounts for f2fs, since all dedicated helpers
for this functionality existsm, so, in this patch we just pass down the
user_namespace argument from the VFS methods to the relevant helpers.

Simple idmap example on f2fs image:

1. truncate -s 128M f2fs.img
2. mkfs.f2fs f2fs.img
3. mount f2fs.img /mnt/f2fs/
4. touch /mnt/f2fs/file

5. ls -ln /mnt/f2fs/
total 0
-rw-r--r-- 1 0 0 0 2月 4 13:17 file

6. ./mount-idmapped --map-mount b:0:1001:1 /mnt/f2fs/ /mnt/scratch_f2fs/

7. ls -ln /mnt/scratch_f2fs/
total 0
-rw-r--r-- 1 1001 1001 0 2月 4 13:17 file

Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
---
fs/f2fs/acl.c | 21 ++++++++++++---------
fs/f2fs/file.c | 23 ++++++++++++++---------
fs/f2fs/namei.c | 41 +++++++++++++++++++++++------------------
fs/f2fs/super.c | 2 +-
4 files changed, 50 insertions(+), 37 deletions(-)

diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index 16e826e01f09..eaa240b21f07 100644
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -204,8 +204,9 @@ struct posix_acl *f2fs_get_acl(struct inode *inode, int type, bool rcu)
return __f2fs_get_acl(inode, type, NULL);
}

-static int f2fs_acl_update_mode(struct inode *inode, umode_t *mode_p,
- struct posix_acl **acl)
+static int f2fs_acl_update_mode(struct user_namespace *mnt_userns,
+ struct inode *inode, umode_t *mode_p,
+ struct posix_acl **acl)
{
umode_t mode = inode->i_mode;
int error;
@@ -218,14 +219,15 @@ static int f2fs_acl_update_mode(struct inode *inode, umode_t *mode_p,
return error;
if (error == 0)
*acl = NULL;
- if (!in_group_p(i_gid_into_mnt(&init_user_ns, inode)) &&
- !capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID))
+ if (!in_group_p(i_gid_into_mnt(mnt_userns, inode)) &&
+ !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID))
mode &= ~S_ISGID;
*mode_p = mode;
return 0;
}

-static int __f2fs_set_acl(struct inode *inode, int type,
+static int __f2fs_set_acl(struct user_namespace *mnt_userns,
+ struct inode *inode, int type,
struct posix_acl *acl, struct page *ipage)
{
int name_index;
@@ -238,7 +240,8 @@ static int __f2fs_set_acl(struct inode *inode, int type,
case ACL_TYPE_ACCESS:
name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
if (acl && !ipage) {
- error = f2fs_acl_update_mode(inode, &mode, &acl);
+ error = f2fs_acl_update_mode(mnt_userns, inode,
+ &mode, &acl);
if (error)
return error;
set_acl_inode(inode, mode);
@@ -279,7 +282,7 @@ int f2fs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
return -EIO;

- return __f2fs_set_acl(inode, type, acl, NULL);
+ return __f2fs_set_acl(mnt_userns, inode, type, acl, NULL);
}

/*
@@ -419,7 +422,7 @@ int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
f2fs_mark_inode_dirty_sync(inode, true);

if (default_acl) {
- error = __f2fs_set_acl(inode, ACL_TYPE_DEFAULT, default_acl,
+ error = __f2fs_set_acl(NULL, inode, ACL_TYPE_DEFAULT, default_acl,
ipage);
posix_acl_release(default_acl);
} else {
@@ -427,7 +430,7 @@ int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
}
if (acl) {
if (!error)
- error = __f2fs_set_acl(inode, ACL_TYPE_ACCESS, acl,
+ error = __f2fs_set_acl(NULL, inode, ACL_TYPE_ACCESS, acl,
ipage);
posix_acl_release(acl);
} else {
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 3a573125002b..135e6ac0792c 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -844,7 +844,7 @@ int f2fs_getattr(struct user_namespace *mnt_userns, const struct path *path,
STATX_ATTR_NODUMP |
STATX_ATTR_VERITY);

- generic_fillattr(&init_user_ns, inode, stat);
+ generic_fillattr(mnt_userns, inode, stat);

/* we need to show initial sectors used for inline_data/dentries */
if ((S_ISREG(inode->i_mode) && f2fs_has_inline_data(inode)) ||
@@ -904,7 +904,7 @@ int f2fs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
!f2fs_is_compress_backend_ready(inode))
return -EOPNOTSUPP;

- err = setattr_prepare(&init_user_ns, dentry, attr);
+ err = setattr_prepare(mnt_userns, dentry, attr);
if (err)
return err;

@@ -980,10 +980,10 @@ int f2fs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
spin_unlock(&F2FS_I(inode)->i_size_lock);
}

- __setattr_copy(&init_user_ns, inode, attr);
+ __setattr_copy(mnt_userns, inode, attr);

if (attr->ia_valid & ATTR_MODE) {
- err = posix_acl_chmod(&init_user_ns, inode, f2fs_get_inode_mode(inode));
+ err = posix_acl_chmod(mnt_userns, inode, f2fs_get_inode_mode(inode));

if (is_inode_flag_set(inode, FI_ACL_MODE)) {
if (!err)
@@ -1989,11 +1989,12 @@ static int f2fs_ioc_getversion(struct file *filp, unsigned long arg)
static int f2fs_ioc_start_atomic_write(struct file *filp)
{
struct inode *inode = file_inode(filp);
+ struct user_namespace *mnt_userns = file_mnt_user_ns(filp);
struct f2fs_inode_info *fi = F2FS_I(inode);
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
int ret;

- if (!inode_owner_or_capable(&init_user_ns, inode))
+ if (!inode_owner_or_capable(mnt_userns, inode))
return -EACCES;

if (!S_ISREG(inode->i_mode))
@@ -2058,9 +2059,10 @@ static int f2fs_ioc_start_atomic_write(struct file *filp)
static int f2fs_ioc_commit_atomic_write(struct file *filp)
{
struct inode *inode = file_inode(filp);
+ struct user_namespace *mnt_userns = file_mnt_user_ns(filp);
int ret;

- if (!inode_owner_or_capable(&init_user_ns, inode))
+ if (!inode_owner_or_capable(mnt_userns, inode))
return -EACCES;

ret = mnt_want_write_file(filp);
@@ -2100,9 +2102,10 @@ static int f2fs_ioc_commit_atomic_write(struct file *filp)
static int f2fs_ioc_start_volatile_write(struct file *filp)
{
struct inode *inode = file_inode(filp);
+ struct user_namespace *mnt_userns = file_mnt_user_ns(filp);
int ret;

- if (!inode_owner_or_capable(&init_user_ns, inode))
+ if (!inode_owner_or_capable(mnt_userns, inode))
return -EACCES;

if (!S_ISREG(inode->i_mode))
@@ -2135,9 +2138,10 @@ static int f2fs_ioc_start_volatile_write(struct file *filp)
static int f2fs_ioc_release_volatile_write(struct file *filp)
{
struct inode *inode = file_inode(filp);
+ struct user_namespace *mnt_userns = file_mnt_user_ns(filp);
int ret;

- if (!inode_owner_or_capable(&init_user_ns, inode))
+ if (!inode_owner_or_capable(mnt_userns, inode))
return -EACCES;

ret = mnt_want_write_file(filp);
@@ -2164,9 +2168,10 @@ static int f2fs_ioc_release_volatile_write(struct file *filp)
static int f2fs_ioc_abort_volatile_write(struct file *filp)
{
struct inode *inode = file_inode(filp);
+ struct user_namespace *mnt_userns = file_mnt_user_ns(filp);
int ret;

- if (!inode_owner_or_capable(&init_user_ns, inode))
+ if (!inode_owner_or_capable(mnt_userns, inode))
return -EACCES;

ret = mnt_want_write_file(filp);
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 0347c5780910..2b23a76bdae9 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -22,7 +22,8 @@
#include "acl.h"
#include <trace/events/f2fs.h>

-static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode)
+static struct inode *f2fs_new_inode(struct user_namespace *mnt_userns,
+ struct inode *dir, umode_t mode)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
nid_t ino;
@@ -46,7 +47,7 @@ static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode)

nid_free = true;

- inode_init_owner(&init_user_ns, inode, dir, mode);
+ inode_init_owner(mnt_userns, inode, dir, mode);

inode->i_ino = ino;
inode->i_blocks = 0;
@@ -67,7 +68,7 @@ static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode)
(F2FS_I(dir)->i_flags & F2FS_PROJINHERIT_FL))
F2FS_I(inode)->i_projid = F2FS_I(dir)->i_projid;
else
- F2FS_I(inode)->i_projid = make_kprojid(&init_user_ns,
+ F2FS_I(inode)->i_projid = make_kprojid(mnt_userns,
F2FS_DEF_PROJID);

err = fscrypt_prepare_new_inode(dir, inode, &encrypt);
@@ -349,7 +350,7 @@ static int f2fs_create(struct user_namespace *mnt_userns, struct inode *dir,
if (err)
return err;

- inode = f2fs_new_inode(dir, mode);
+ inode = f2fs_new_inode(mnt_userns, dir, mode);
if (IS_ERR(inode))
return PTR_ERR(inode);

@@ -679,7 +680,7 @@ static int f2fs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
if (err)
return err;

- inode = f2fs_new_inode(dir, S_IFLNK | S_IRWXUGO);
+ inode = f2fs_new_inode(mnt_userns, dir, S_IFLNK | S_IRWXUGO);
if (IS_ERR(inode))
return PTR_ERR(inode);

@@ -750,7 +751,7 @@ static int f2fs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
if (err)
return err;

- inode = f2fs_new_inode(dir, S_IFDIR | mode);
+ inode = f2fs_new_inode(mnt_userns, dir, S_IFDIR | mode);
if (IS_ERR(inode))
return PTR_ERR(inode);

@@ -807,7 +808,7 @@ static int f2fs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
if (err)
return err;

- inode = f2fs_new_inode(dir, mode);
+ inode = f2fs_new_inode(mnt_userns, dir, mode);
if (IS_ERR(inode))
return PTR_ERR(inode);

@@ -834,8 +835,9 @@ static int f2fs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
return err;
}

-static int __f2fs_tmpfile(struct inode *dir, struct dentry *dentry,
- umode_t mode, struct inode **whiteout)
+static int __f2fs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
+ struct dentry *dentry, umode_t mode,
+ struct inode **whiteout)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
struct inode *inode;
@@ -845,7 +847,7 @@ static int __f2fs_tmpfile(struct inode *dir, struct dentry *dentry,
if (err)
return err;

- inode = f2fs_new_inode(dir, mode);
+ inode = f2fs_new_inode(mnt_userns, dir, mode);
if (IS_ERR(inode))
return PTR_ERR(inode);

@@ -909,20 +911,22 @@ static int f2fs_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
if (!f2fs_is_checkpoint_ready(sbi))
return -ENOSPC;

- return __f2fs_tmpfile(dir, dentry, mode, NULL);
+ return __f2fs_tmpfile(mnt_userns, dir, dentry, mode, NULL);
}

-static int f2fs_create_whiteout(struct inode *dir, struct inode **whiteout)
+static int f2fs_create_whiteout(struct user_namespace *mnt_userns,
+ struct inode *dir, struct inode **whiteout)
{
if (unlikely(f2fs_cp_error(F2FS_I_SB(dir))))
return -EIO;

- return __f2fs_tmpfile(dir, NULL, S_IFCHR | WHITEOUT_MODE, whiteout);
+ return __f2fs_tmpfile(mnt_userns, dir, NULL,
+ S_IFCHR | WHITEOUT_MODE, whiteout);
}

-static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
- struct inode *new_dir, struct dentry *new_dentry,
- unsigned int flags)
+static int f2fs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+ struct dentry *old_dentry, struct inode *new_dir,
+ struct dentry *new_dentry, unsigned int flags)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(old_dir);
struct inode *old_inode = d_inode(old_dentry);
@@ -960,7 +964,7 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
}

if (flags & RENAME_WHITEOUT) {
- err = f2fs_create_whiteout(old_dir, &whiteout);
+ err = f2fs_create_whiteout(mnt_userns, old_dir, &whiteout);
if (err)
return err;
}
@@ -1300,7 +1304,8 @@ static int f2fs_rename2(struct user_namespace *mnt_userns,
* VFS has already handled the new dentry existence case,
* here, we just deal with "RENAME_NOREPLACE" as regular rename.
*/
- return f2fs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
+ return f2fs_rename(mnt_userns, old_dir, old_dentry,
+ new_dir, new_dentry, flags);
}

static const char *f2fs_encrypted_get_link(struct dentry *dentry,
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index cc0429279b4c..41ef1273f2f2 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4528,7 +4528,7 @@ static struct file_system_type f2fs_fs_type = {
.name = "f2fs",
.mount = f2fs_mount,
.kill_sb = kill_f2fs_super,
- .fs_flags = FS_REQUIRES_DEV,
+ .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
};
MODULE_ALIAS_FS("f2fs");

--
2.32.0