On 3/18/25 11:01 PM, NeilBrown wrote:
> nfsd uses some VFS interfaces (such as vfs_mkdir) which take an explicit
> mnt_idmap, and it passes &nop_mnt_idmap as nfsd doesn't yet support
> idmapped mounts.
>
> It also uses the lookup_one_len() family of functions which implicitly
> use &nop_mnt_idmap. This mixture of implicit and explicit could be
> confusing. When we eventually update nfsd to support idmap mounts it
> would be best if all places which need an idmap determined from the
> mount point were similar and easily found.
>
> So this patch changes nfsd to use lookup_one(), lookup_one_unlocked(),
> and lookup_one_positive_unlocked(), passing &nop_mnt_idmap.
>
> This has the benefit of removing some uses of the lookup_one_len
> functions where permission checking is actually needed. Many callers
> don't care about permission checking and using these function only where
> permission checking is needed is a valuable simplification.
>
> This change requires passing the name in a qstr. Currently this is a
> little clumsy, but if nfsd is changed to use qstr more broadly it will
> result in a net improvement.
>
> Signed-off-by: NeilBrown <neil@xxxxxxxxxx>
> ---
> fs/nfsd/nfs3proc.c | 4 +++-
> fs/nfsd/nfs3xdr.c | 4 +++-
> fs/nfsd/nfs4proc.c | 4 +++-
> fs/nfsd/nfs4recover.c | 13 +++++++------
> fs/nfsd/nfs4xdr.c | 4 +++-
> fs/nfsd/nfsproc.c | 6 ++++--
> fs/nfsd/vfs.c | 17 +++++++++--------
> 7 files changed, 32 insertions(+), 20 deletions(-)
>
> diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
> index 372bdcf5e07a..9fa8ad08b1cd 100644
> --- a/fs/nfsd/nfs3proc.c
> +++ b/fs/nfsd/nfs3proc.c
> @@ -284,7 +284,9 @@ nfsd3_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
>
> inode_lock_nested(inode, I_MUTEX_PARENT);
>
> - child = lookup_one_len(argp->name, parent, argp->len);
> + child = lookup_one(&nop_mnt_idmap,
> + QSTR_LEN(argp->name, argp->len),
> + parent);
> if (IS_ERR(child)) {
> status = nfserrno(PTR_ERR(child));
> goto out;
> diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
> index a7a07470c1f8..5a626e24a334 100644
> --- a/fs/nfsd/nfs3xdr.c
> +++ b/fs/nfsd/nfs3xdr.c
> @@ -1001,7 +1001,9 @@ compose_entry_fh(struct nfsd3_readdirres *cd, struct svc_fh *fhp,
> } else
> dchild = dget(dparent);
> } else
> - dchild = lookup_positive_unlocked(name, dparent, namlen);
> + dchild = lookup_one_positive_unlocked(&nop_mnt_idmap,
> + QSTR_LEN(name, namlen),
> + dparent);
> if (IS_ERR(dchild))
> return rv;
> if (d_mountpoint(dchild))
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index f6e06c779d09..5860f3825be2 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -266,7 +266,9 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
>
> inode_lock_nested(inode, I_MUTEX_PARENT);
>
> - child = lookup_one_len(open->op_fname, parent, open->op_fnamelen);
> + child = lookup_one(&nop_mnt_idmap, QSTR_LEN(open->op_fname,
> + open->op_fnamelen),
> + parent);
> if (IS_ERR(child)) {
> status = nfserrno(PTR_ERR(child));
> goto out;
> diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
> index c1d9bd07285f..5c1cb5c3c13e 100644
> --- a/fs/nfsd/nfs4recover.c
> +++ b/fs/nfsd/nfs4recover.c
> @@ -218,7 +218,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp)
> /* lock the parent */
> inode_lock(d_inode(dir));
>
> - dentry = lookup_one_len(dname, dir, HEXDIR_LEN-1);
> + dentry = lookup_one(&nop_mnt_idmap, QSTR(dname), dir);
> if (IS_ERR(dentry)) {
> status = PTR_ERR(dentry);
> goto out_unlock;
> @@ -316,7 +316,8 @@ nfsd4_list_rec_dir(recdir_func *f, struct nfsd_net *nn)
> list_for_each_entry_safe(entry, tmp, &ctx.names, list) {
> if (!status) {
> struct dentry *dentry;
> - dentry = lookup_one_len(entry->name, dir, HEXDIR_LEN-1);
> + dentry = lookup_one(&nop_mnt_idmap,
> + QSTR(entry->name), dir);
> if (IS_ERR(dentry)) {
> status = PTR_ERR(dentry);
> break;
> @@ -339,16 +340,16 @@ nfsd4_list_rec_dir(recdir_func *f, struct nfsd_net *nn)
> }
>
> static int
> -nfsd4_unlink_clid_dir(char *name, int namlen, struct nfsd_net *nn)
> +nfsd4_unlink_clid_dir(char *name, struct nfsd_net *nn)
> {
> struct dentry *dir, *dentry;
> int status;
>
> - dprintk("NFSD: nfsd4_unlink_clid_dir. name %.*s\n", namlen, name);
> + dprintk("NFSD: nfsd4_unlink_clid_dir. name %s\n", name);
>
> dir = nn->rec_file->f_path.dentry;
> inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
> - dentry = lookup_one_len(name, dir, namlen);
> + dentry = lookup_one(&nop_mnt_idmap, QSTR(name), dir);
> if (IS_ERR(dentry)) {
> status = PTR_ERR(dentry);
> goto out_unlock;
> @@ -408,7 +409,7 @@ nfsd4_remove_clid_dir(struct nfs4_client *clp)
> if (status < 0)
> goto out_drop_write;
>
> - status = nfsd4_unlink_clid_dir(dname, HEXDIR_LEN-1, nn);
> + status = nfsd4_unlink_clid_dir(dname, nn);
> nfs4_reset_creds(original_cred);
> if (status == 0) {
> vfs_fsync(nn->rec_file, 0);
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index e67420729ecd..16be860b1f79 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -3812,7 +3812,9 @@ nfsd4_encode_entry4_fattr(struct nfsd4_readdir *cd, const char *name,
> __be32 nfserr;
> int ignore_crossmnt = 0;
>
> - dentry = lookup_positive_unlocked(name, cd->rd_fhp->fh_dentry, namlen);
> + dentry = lookup_one_positive_unlocked(&nop_mnt_idmap,
> + QSTR_LEN(name, namlen),
> + cd->rd_fhp->fh_dentry);
> if (IS_ERR(dentry))
> return nfserrno(PTR_ERR(dentry));
>
> diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
> index 6dda081eb24c..ac7d7f858846 100644
> --- a/fs/nfsd/nfsproc.c
> +++ b/fs/nfsd/nfsproc.c
> @@ -312,7 +312,9 @@ nfsd_proc_create(struct svc_rqst *rqstp)
> }
>
> inode_lock_nested(dirfhp->fh_dentry->d_inode, I_MUTEX_PARENT);
> - dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len);
> + dchild = lookup_one(&nop_mnt_idmap, QSTR_LEN(argp->name,
> + argp->len),
> + dirfhp->fh_dentry);
> if (IS_ERR(dchild)) {
> resp->status = nfserrno(PTR_ERR(dchild));
> goto out_unlock;
> @@ -331,7 +333,7 @@ nfsd_proc_create(struct svc_rqst *rqstp)
> */
> resp->status = nfserr_acces;
> if (!newfhp->fh_dentry) {
> - printk(KERN_WARNING
> + printk(KERN_WARNING
> "nfsd_proc_create: file handle not verified\n");
> goto out_unlock;
> }
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 34d7aa531662..c0c94619af92 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -265,7 +265,8 @@ nfsd_lookup_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp,
> goto out_nfserr;
> }
> } else {
> - dentry = lookup_one_len_unlocked(name, dparent, len);
> + dentry = lookup_one_unlocked(&nop_mnt_idmap,
> + QSTR_LEN(name, len), dparent);
> host_err = PTR_ERR(dentry);
> if (IS_ERR(dentry))
> goto out_nfserr;
> @@ -923,7 +924,7 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, umode_t type,
> * directories, but we never have and it doesn't seem to have
> * caused anyone a problem. If we were to change this, note
> * also that our filldir callbacks would need a variant of
> - * lookup_one_len that doesn't check permissions.
> + * lookup_one_positive_unlocked() that doesn't check permissions.
> */
> if (type == S_IFREG)
> may_flags |= NFSD_MAY_OWNER_OVERRIDE;
> @@ -1555,7 +1556,7 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
> return nfserrno(host_err);
>
> inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
> - dchild = lookup_one_len(fname, dentry, flen);
> + dchild = lookup_one(&nop_mnt_idmap, QSTR_LEN(fname, flen), dentry);
> host_err = PTR_ERR(dchild);
> if (IS_ERR(dchild)) {
> err = nfserrno(host_err);
> @@ -1660,7 +1661,7 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
>
> dentry = fhp->fh_dentry;
> inode_lock_nested(dentry->d_inode, I_MUTEX_PARENT);
> - dnew = lookup_one_len(fname, dentry, flen);
> + dnew = lookup_one(&nop_mnt_idmap, QSTR_LEN(fname, flen), dentry);
> if (IS_ERR(dnew)) {
> err = nfserrno(PTR_ERR(dnew));
> inode_unlock(dentry->d_inode);
> @@ -1726,7 +1727,7 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
> dirp = d_inode(ddir);
> inode_lock_nested(dirp, I_MUTEX_PARENT);
>
> - dnew = lookup_one_len(name, ddir, len);
> + dnew = lookup_one(&nop_mnt_idmap, QSTR_LEN(name, len), ddir);
> if (IS_ERR(dnew)) {
> err = nfserrno(PTR_ERR(dnew));
> goto out_unlock;
> @@ -1839,7 +1840,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
> if (err != nfs_ok)
> goto out_unlock;
>
> - odentry = lookup_one_len(fname, fdentry, flen);
> + odentry = lookup_one(&nop_mnt_idmap, QSTR_LEN(fname, flen), fdentry);
> host_err = PTR_ERR(odentry);
> if (IS_ERR(odentry))
> goto out_nfserr;
> @@ -1851,7 +1852,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
> if (odentry == trap)
> goto out_dput_old;
>
> - ndentry = lookup_one_len(tname, tdentry, tlen);
> + ndentry = lookup_one(&nop_mnt_idmap, QSTR_LEN(tname, tlen), tdentry);
> host_err = PTR_ERR(ndentry);
> if (IS_ERR(ndentry))
> goto out_dput_old;
> @@ -1948,7 +1949,7 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
> dirp = d_inode(dentry);
> inode_lock_nested(dirp, I_MUTEX_PARENT);
>
> - rdentry = lookup_one_len(fname, dentry, flen);
> + rdentry = lookup_one(&nop_mnt_idmap, QSTR_LEN(fname, flen), dentry);
> host_err = PTR_ERR(rdentry);
> if (IS_ERR(rdentry))
> goto out_unlock;
Acked-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
--
Chuck Lever
