On Sat, 20 Jan 2024 16:23:38 +0100
Christian Brauner <brauner@xxxxxxxxxx> wrote:
> On Mon, Jan 08, 2024 at 01:08:21PM +0100, Alexander Mikhalitsyn wrote:
> > Cc: Christian Brauner <brauner@xxxxxxxxxx>
> > Cc: Seth Forshee <sforshee@xxxxxxxxxx>
> > Cc: Miklos Szeredi <miklos@xxxxxxxxxx>
> > Cc: Amir Goldstein <amir73il@xxxxxxxxx>
> > Cc: Bernd Schubert <bschubert@xxxxxxx>
> > Cc: <linux-fsdevel@xxxxxxxxxxxxxxx>
> > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
> > ---
> > fs/fuse/dir.c | 32 +++++++++++++++++++++-----------
> > fs/fuse/file.c | 2 +-
> > fs/fuse/fuse_i.h | 4 ++--
> > 3 files changed, 24 insertions(+), 14 deletions(-)
> >
> > diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
> > index f7c2c54f7122..5fbb7100ad1c 100644
> > --- a/fs/fuse/dir.c
> > +++ b/fs/fuse/dir.c
> > @@ -1739,17 +1739,27 @@ static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
> > return true;
> > }
> >
> > -static void iattr_to_fattr(struct fuse_conn *fc, struct iattr *iattr,
> > - struct fuse_setattr_in *arg, bool trust_local_cmtime)
> > +static void iattr_to_fattr(struct mnt_idmap *idmap, struct fuse_conn *fc,
> > + struct iattr *iattr, struct fuse_setattr_in *arg,
> > + bool trust_local_cmtime)
> > {
> > unsigned ivalid = iattr->ia_valid;
> >
> > if (ivalid & ATTR_MODE)
> > arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
> > - if (ivalid & ATTR_UID)
> > - arg->valid |= FATTR_UID, arg->uid = from_kuid(fc->user_ns, iattr->ia_uid);
> > - if (ivalid & ATTR_GID)
> > - arg->valid |= FATTR_GID, arg->gid = from_kgid(fc->user_ns, iattr->ia_gid);
> > +
> > + if (ivalid & ATTR_UID) {
> > + kuid_t fsuid = from_vfsuid(idmap, fc->user_ns, iattr->ia_vfsuid);
> > + arg->valid |= FATTR_UID;
> > + arg->uid = from_kuid(fc->user_ns, fsuid);
> > + }
> > +
> > + if (ivalid & ATTR_GID) {
> > + kgid_t fsgid = from_vfsgid(idmap, fc->user_ns, iattr->ia_vfsgid);
> > + arg->valid |= FATTR_GID;
> > + arg->gid = from_kgid(fc->user_ns, fsgid);
> > + }
> > +
> > if (ivalid & ATTR_SIZE)
> > arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
> > if (ivalid & ATTR_ATIME) {
> > @@ -1869,8 +1879,8 @@ int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
> > * vmtruncate() doesn't allow for this case, so do the rlimit checking
> > * and the actual truncation by hand.
> > */
> > -int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
> > - struct file *file)
> > +int fuse_do_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> > + struct iattr *attr, struct file *file)
> > {
> > struct inode *inode = d_inode(dentry);
> > struct fuse_mount *fm = get_fuse_mount(inode);
> > @@ -1890,7 +1900,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
> > if (!fc->default_permissions)
> > attr->ia_valid |= ATTR_FORCE;
> >
> > - err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
> > + err = setattr_prepare(idmap, dentry, attr);
> > if (err)
> > return err;
> >
> > @@ -1949,7 +1959,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
> >
> > memset(&inarg, 0, sizeof(inarg));
> > memset(&outarg, 0, sizeof(outarg));
> > - iattr_to_fattr(fc, attr, &inarg, trust_local_cmtime);
> > + iattr_to_fattr(idmap, fc, attr, &inarg, trust_local_cmtime);
> > if (file) {
> > struct fuse_file *ff = file->private_data;
> > inarg.valid |= FATTR_FH;
> > @@ -2084,7 +2094,7 @@ static int fuse_setattr(struct mnt_idmap *idmap, struct dentry *entry,
> > if (!attr->ia_valid)
> > return 0;
> >
> > - ret = fuse_do_setattr(entry, attr, file);
> > + ret = fuse_do_setattr(idmap, entry, attr, file);
> > if (!ret) {
> > /*
> > * If filesystem supports acls it may have updated acl xattrs in
> > diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> > index a660f1f21540..e0fe5497a548 100644
> > --- a/fs/fuse/file.c
> > +++ b/fs/fuse/file.c
> > @@ -2870,7 +2870,7 @@ static void fuse_do_truncate(struct file *file)
> > attr.ia_file = file;
> > attr.ia_valid |= ATTR_FILE;
> >
> > - fuse_do_setattr(file_dentry(file), &attr, file);
> > + fuse_do_setattr(&nop_mnt_idmap, file_dentry(file), &attr, file);
>
> Same as for the other patch. Please leave a comment in the commit
> message that briefly explains why it's ok to pass &nop_mnt_idmap here.
> It'll help us later. :)
Sure, will be fixed in -v2 ;-)
Explanation here is that in this specific case attr.ia_valid = ATTR_SIZE | ATTR_FILE,
which but we only need an idmapping for ATTR_UID | ATTR_GID.
>From the other side, having struct file pointer means that getting an idmapping as easy as file_mnt_idmap(file),
and probably it's easier to pass an idmapping in this specific case rather than skipping it for a valid reasons.
What do you think about this?
Kind regards,
Alex
