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nfsd: Use lookup_one() rather than lookup_one_len()

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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@brown.name>
Link: https://lore.kernel.org/r/20250319031545.2999807-3-neil@brown.name
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
NeilBrown 2025-03-19 14:01:33 +11:00 • committed by Christian Brauner
parent 5741909697
commit 8ad9248471
No known key found for this signature in database
GPG key ID: 91C61BC06578DCA2
7 changed files with 31 additions and 20 deletions
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4
fs/nfsd/nfs3proc.c
View file

@ -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;

4
fs/nfsd/nfs3xdr.c
View file

@ -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))

4
fs/nfsd/nfs4proc.c
View file

@ -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;

13
fs/nfsd/nfs4recover.c
View file

@ -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);

4
fs/nfsd/nfs4xdr.c
View file

@ -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));

5
fs/nfsd/nfsproc.c
View file

@ -312,7 +312,8 @@ 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 +332,7 @@ 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;
}

17
fs/nfsd/vfs.c
View file

@ -264,7 +264,8 @@ 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;
@ -922,7 +923,7 @@ 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;
@ -1554,7 +1555,7 @@ 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);
@ -1659,7 +1660,7 @@ 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);
@ -1734,7 +1735,7 @@ 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)) {
host_err = PTR_ERR(dnew);
goto out_unlock;
@ -1867,7 +1868,7 @@ retry:
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;
@ -1880,7 +1881,7 @@ retry:
goto out_dput_old;
type = d_inode(odentry)->i_mode & S_IFMT;
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;
@ -1998,7 +1999,7 @@ 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;