f2fs: support idmapped mounts

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@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 23 insertions, 18 deletions

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 @@ out:
 	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,