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charset="utf-8" From: Khalid Aziz Make msharefs filesystem writable and allow creating directories to support better access control to mshare'd regions defined in msharefs. Signed-off-by: Khalid Aziz Signed-off-by: Anthony Yznaga --- mm/mshare.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 115 insertions(+), 1 deletion(-) diff --git a/mm/mshare.c b/mm/mshare.c index d666471bc94b..c43b53a7323a 100644 --- a/mm/mshare.c +++ b/mm/mshare.c @@ -19,14 +19,128 @@ =20 const unsigned long mshare_align =3D P4D_SIZE; =20 +static const struct inode_operations msharefs_dir_inode_ops; +static const struct inode_operations msharefs_file_inode_ops; + static const struct file_operations msharefs_file_operations =3D { .open =3D simple_open, }; =20 +static struct inode +*msharefs_get_inode(struct mnt_idmap *idmap, struct super_block *sb, + const struct inode *dir, umode_t mode) +{ + struct inode *inode =3D new_inode(sb); + + if (!inode) + return ERR_PTR(-ENOMEM); + + inode->i_ino =3D get_next_ino(); + inode_init_owner(&nop_mnt_idmap, inode, dir, mode); + simple_inode_init_ts(inode); + + switch (mode & S_IFMT) { + case S_IFREG: + inode->i_op =3D &msharefs_file_inode_ops; + inode->i_fop =3D &msharefs_file_operations; + break; + case S_IFDIR: + inode->i_op =3D &msharefs_dir_inode_ops; + inode->i_fop =3D &simple_dir_operations; + inc_nlink(inode); + break; + default: + iput(inode); + return ERR_PTR(-EINVAL); + } + + return inode; +} + +static int +msharefs_mknod(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + struct inode *inode; + + inode =3D msharefs_get_inode(idmap, dir->i_sb, dir, mode); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + d_instantiate(dentry, inode); + dget(dentry); + inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); + + return 0; +} + +static int +msharefs_create(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode, bool excl) +{ + return msharefs_mknod(idmap, dir, dentry, mode | S_IFREG); +} + +static struct dentry * +msharefs_mkdir(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + int ret =3D msharefs_mknod(idmap, dir, dentry, mode | S_IFDIR); + + if (!ret) + inc_nlink(dir); + return ERR_PTR(ret); +} + struct msharefs_info { struct dentry *info_dentry; }; =20 +static inline bool +is_msharefs_info_file(const struct dentry *dentry) +{ + struct msharefs_info *info =3D dentry->d_sb->s_fs_info; + + return info->info_dentry =3D=3D dentry; +} + +static int +msharefs_rename(struct mnt_idmap *idmap, + struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry, + unsigned int flags) +{ + if (is_msharefs_info_file(old_dentry) || + is_msharefs_info_file(new_dentry)) + return -EPERM; + + return simple_rename(idmap, old_dir, old_dentry, new_dir, + new_dentry, flags); +} + +static int +msharefs_unlink(struct inode *dir, struct dentry *dentry) +{ + if (is_msharefs_info_file(dentry)) + return -EPERM; + + return simple_unlink(dir, dentry); +} + +static const struct inode_operations msharefs_file_inode_ops =3D { + .setattr =3D simple_setattr, +}; + +static const struct inode_operations msharefs_dir_inode_ops =3D { + .create =3D msharefs_create, + .lookup =3D simple_lookup, + .link =3D simple_link, + .unlink =3D msharefs_unlink, + .mkdir =3D msharefs_mkdir, + .rmdir =3D simple_rmdir, + .rename =3D msharefs_rename, +}; + static ssize_t mshare_info_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) @@ -106,7 +220,7 @@ msharefs_fill_super(struct super_block *sb, struct fs_c= ontext *fc) inode->i_ino =3D 1; inode->i_mode =3D S_IFDIR | 0777; simple_inode_init_ts(inode); - inode->i_op =3D &simple_dir_inode_operations; + inode->i_op =3D &msharefs_dir_inode_ops; inode->i_fop =3D &simple_dir_operations; set_nlink(inode, 2); =20 --=20 2.47.1