vboxsf: don't allow to change the inode type

vboxsf_init_inode() is used both for initial setup of inode and for metadata
updates.  Tell it whether we are updating a live inode or setting up a new
instance and have it refuse to change type in the former case.

[fixed the braino caught by Hans de Goede <hdegoede@redhat.com>]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/vboxsf/dir.c b/fs/vboxsf/dir.c
index 7aee0ec..eac6788 100644 (file)
--- a/fs/vboxsf/dir.c
+++ b/fs/vboxsf/dir.c
@@ -225,7 +225,7 @@ static struct dentry *vboxsf_dir_lookup(struct inode *parent,
        } else {
                inode = vboxsf_new_inode(parent->i_sb);
                if (!IS_ERR(inode))
-                       vboxsf_init_inode(sbi, inode, &fsinfo);
+                       vboxsf_init_inode(sbi, inode, &fsinfo, false);
        }
 
        return d_splice_alias(inode, dentry);
@@ -245,7 +245,7 @@ static int vboxsf_dir_instantiate(struct inode *parent, struct dentry *dentry,
        sf_i = VBOXSF_I(inode);
        /* The host may have given us different attr then requested */
        sf_i->force_restat = 1;
-       vboxsf_init_inode(sbi, inode, info);
+       vboxsf_init_inode(sbi, inode, info, false);
 
        d_instantiate(dentry, inode);
 

diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
index d7816c0..4f5e59f 100644 (file)
--- a/fs/vboxsf/super.c
+++ b/fs/vboxsf/super.c
@@ -207,7 +207,7 @@ static int vboxsf_fill_super(struct super_block *sb, struct fs_context *fc)
                err = -ENOMEM;
                goto fail_unmap;
        }
-       vboxsf_init_inode(sbi, iroot, &sbi->root_info);
+       vboxsf_init_inode(sbi, iroot, &sbi->root_info, false);
        unlock_new_inode(iroot);
 
        droot = d_make_root(iroot);
@@ -418,7 +418,7 @@ static int vboxsf_reconfigure(struct fs_context *fc)
 
        /* Apply changed options to the root inode */
        sbi->o = ctx->o;
-       vboxsf_init_inode(sbi, iroot, &sbi->root_info);
+       vboxsf_init_inode(sbi, iroot, &sbi->root_info, true);
 
        return 0;
 }

diff --git a/fs/vboxsf/utils.c b/fs/vboxsf/utils.c
index 3b847e3..aec2ebf 100644 (file)
--- a/fs/vboxsf/utils.c
+++ b/fs/vboxsf/utils.c
@@ -45,12 +45,12 @@ struct inode *vboxsf_new_inode(struct super_block *sb)
 }
 
 /* set [inode] attributes based on [info], uid/gid based on [sbi] */
-void vboxsf_init_inode(struct vboxsf_sbi *sbi, struct inode *inode,
-                      const struct shfl_fsobjinfo *info)
+int vboxsf_init_inode(struct vboxsf_sbi *sbi, struct inode *inode,
+                      const struct shfl_fsobjinfo *info, bool reinit)
 {
        const struct shfl_fsobjattr *attr;
        s64 allocated;
-       int mode;
+       umode_t mode;
 
        attr = &info->attr;
 
@@ -75,29 +75,44 @@ void vboxsf_init_inode(struct vboxsf_sbi *sbi, struct inode *inode,
        inode->i_mapping->a_ops = &vboxsf_reg_aops;
 
        if (SHFL_IS_DIRECTORY(attr->mode)) {
-               inode->i_mode = sbi->o.dmode_set ? sbi->o.dmode : mode;
-               inode->i_mode &= ~sbi->o.dmask;
-               inode->i_mode |= S_IFDIR;
-               inode->i_op = &vboxsf_dir_iops;
-               inode->i_fop = &vboxsf_dir_fops;
-               /*
-                * XXX: this probably should be set to the number of entries
-                * in the directory plus two (. ..)
-                */
-               set_nlink(inode, 1);
+               if (sbi->o.dmode_set)
+                       mode = sbi->o.dmode;
+               mode &= ~sbi->o.dmask;
+               mode |= S_IFDIR;
+               if (!reinit) {
+                       inode->i_op = &vboxsf_dir_iops;
+                       inode->i_fop = &vboxsf_dir_fops;
+                       /*
+                        * XXX: this probably should be set to the number of entries
+                        * in the directory plus two (. ..)
+                        */
+                       set_nlink(inode, 1);
+               } else if (!S_ISDIR(inode->i_mode))
+                       return -ESTALE;
+               inode->i_mode = mode;
        } else if (SHFL_IS_SYMLINK(attr->mode)) {
-               inode->i_mode = sbi->o.fmode_set ? sbi->o.fmode : mode;
-               inode->i_mode &= ~sbi->o.fmask;
-               inode->i_mode |= S_IFLNK;
-               inode->i_op = &vboxsf_lnk_iops;
-               set_nlink(inode, 1);
+               if (sbi->o.fmode_set)
+                       mode = sbi->o.fmode;
+               mode &= ~sbi->o.fmask;
+               mode |= S_IFLNK;
+               if (!reinit) {
+                       inode->i_op = &vboxsf_lnk_iops;
+                       set_nlink(inode, 1);
+               } else if (!S_ISLNK(inode->i_mode))
+                       return -ESTALE;
+               inode->i_mode = mode;
        } else {
-               inode->i_mode = sbi->o.fmode_set ? sbi->o.fmode : mode;
-               inode->i_mode &= ~sbi->o.fmask;
-               inode->i_mode |= S_IFREG;
-               inode->i_op = &vboxsf_reg_iops;
-               inode->i_fop = &vboxsf_reg_fops;
-               set_nlink(inode, 1);
+               if (sbi->o.fmode_set)
+                       mode = sbi->o.fmode;
+               mode &= ~sbi->o.fmask;
+               mode |= S_IFREG;
+               if (!reinit) {
+                       inode->i_op = &vboxsf_reg_iops;
+                       inode->i_fop = &vboxsf_reg_fops;
+                       set_nlink(inode, 1);
+               } else if (!S_ISREG(inode->i_mode))
+                       return -ESTALE;
+               inode->i_mode = mode;
        }
 
        inode->i_uid = sbi->o.uid;
@@ -116,6 +131,7 @@ void vboxsf_init_inode(struct vboxsf_sbi *sbi, struct inode *inode,
                                 info->change_time.ns_relative_to_unix_epoch);
        inode->i_mtime = ns_to_timespec64(
                           info->modification_time.ns_relative_to_unix_epoch);
+       return 0;
 }
 
 int vboxsf_create_at_dentry(struct dentry *dentry,
@@ -199,7 +215,9 @@ int vboxsf_inode_revalidate(struct dentry *dentry)
 
        dentry->d_time = jiffies;
        sf_i->force_restat = 0;
-       vboxsf_init_inode(sbi, inode, &info);
+       err = vboxsf_init_inode(sbi, inode, &info, true);
+       if (err)
+               return err;
 
        /*
         * If the file was changed on the host side we need to invalidate the

diff --git a/fs/vboxsf/vfsmod.h b/fs/vboxsf/vfsmod.h
index 760524e..6a7a9ce 100644 (file)
--- a/fs/vboxsf/vfsmod.h
+++ b/fs/vboxsf/vfsmod.h
@@ -82,8 +82,8 @@ extern const struct dentry_operations vboxsf_dentry_ops;
 
 /* from utils.c */
 struct inode *vboxsf_new_inode(struct super_block *sb);
-void vboxsf_init_inode(struct vboxsf_sbi *sbi, struct inode *inode,
-                      const struct shfl_fsobjinfo *info);
+int vboxsf_init_inode(struct vboxsf_sbi *sbi, struct inode *inode,
+                      const struct shfl_fsobjinfo *info, bool reinit);
 int vboxsf_create_at_dentry(struct dentry *dentry,
                            struct shfl_createparms *params);
 int vboxsf_stat(struct vboxsf_sbi *sbi, struct shfl_string *path,