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ovl: use ovl_lookup_upper() wrapper

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Introduce ovl_lookup_upper() as a simple wrapper around lookup_one().
Make it clear in the helper's name that this only operates on the upper
layer. The wrapper will take upper layer's idmapping into account when
checking permission in lookup_one().

Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Christian Brauner 2022-04-04 12:51:49 +02:00 committed by Miklos Szeredi
parent a15506eac9
commit 22f289ce1f
6 changed files with 37 additions and 28 deletions
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12
fs/overlayfs/copy_up.c
View File

@ -486,7 +486,7 @@ static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
if (err)
goto out;
index = lookup_one_len(name.name, indexdir, name.len);
index = ovl_lookup_upper(ofs, name.name, indexdir, name.len);
if (IS_ERR(index)) {
err = PTR_ERR(index);
} else {
@ -535,8 +535,8 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c)
return err;
inode_lock_nested(udir, I_MUTEX_PARENT);
upper = lookup_one_len(c->dentry->d_name.name, upperdir,
c->dentry->d_name.len);
upper = ovl_lookup_upper(ofs, c->dentry->d_name.name, upperdir,
c->dentry->d_name.len);
err = PTR_ERR(upper);
if (!IS_ERR(upper)) {
err = ovl_do_link(ofs, ovl_dentry_upper(c->dentry), udir, upper);
@ -699,7 +699,8 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
goto cleanup;
}
upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len);
upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
c->destname.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
goto cleanup;
@ -751,7 +752,8 @@ static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c)
inode_lock_nested(udir, I_MUTEX_PARENT);
upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len);
upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
c->destname.len);
err = PTR_ERR(upper);
if (!IS_ERR(upper)) {
err = ovl_do_link(ofs, temp, udir, upper);

31
fs/overlayfs/dir.c
View File

@ -51,7 +51,7 @@ struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir)
/* counter is allowed to wrap, since temp dentries are ephemeral */
snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
temp = lookup_one_len(name, workdir, strlen(name));
temp = ovl_lookup_upper(ofs, name, workdir, strlen(name));
if (!IS_ERR(temp) && temp->d_inode) {
pr_err("workdir/%s already exists\n", name);
dput(temp);
@ -155,8 +155,8 @@ int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir,
* to it unhashed and negative. If that happens, try to
* lookup a new hashed and positive dentry.
*/
d = lookup_one_len(dentry->d_name.name, dentry->d_parent,
dentry->d_name.len);
d = ovl_lookup_upper(ofs, dentry->d_name.name, dentry->d_parent,
dentry->d_name.len);
if (IS_ERR(d)) {
pr_warn("failed lookup after mkdir (%pd2, err=%i).\n",
dentry, err);
@ -333,9 +333,8 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
inode_lock_nested(udir, I_MUTEX_PARENT);
newdentry = ovl_create_real(ofs, udir,
lookup_one_len(dentry->d_name.name,
upperdir,
dentry->d_name.len),
ovl_lookup_upper(ofs, dentry->d_name.name,
upperdir, dentry->d_name.len),
attr);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
@ -488,8 +487,8 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
if (err)
goto out;
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
goto out_unlock;
@ -771,8 +770,8 @@ static int ovl_remove_and_whiteout(struct dentry *dentry,
if (err)
goto out_dput;
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
goto out_unlock;
@ -819,8 +818,8 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir,
}
inode_lock_nested(dir, I_MUTEX_PARENT);
upper = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(upper);
if (IS_ERR(upper))
goto out_unlock;
@ -1195,8 +1194,8 @@ static int ovl_rename(struct user_namespace *mnt_userns, struct inode *olddir,
trap = lock_rename(new_upperdir, old_upperdir);
olddentry = lookup_one_len(old->d_name.name, old_upperdir,
old->d_name.len);
olddentry = ovl_lookup_upper(ofs, old->d_name.name, old_upperdir,
old->d_name.len);
err = PTR_ERR(olddentry);
if (IS_ERR(olddentry))
goto out_unlock;
@ -1205,8 +1204,8 @@ static int ovl_rename(struct user_namespace *mnt_userns, struct inode *olddir,
if (!ovl_matches_upper(old, olddentry))
goto out_dput_old;
newdentry = lookup_one_len(new->d_name.name, new_upperdir,
new->d_name.len);
newdentry = ovl_lookup_upper(ofs, new->d_name.name, new_upperdir,
new->d_name.len);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_dput_old;

8
fs/overlayfs/overlayfs.h
View File

@ -7,6 +7,7 @@
#include <linux/kernel.h>
#include <linux/uuid.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include "ovl_entry.h"
#undef pr_fmt
@ -310,6 +311,13 @@ static inline struct dentry *ovl_do_tmpfile(struct ovl_fs *ofs,
return ret;
}
static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
const char *name,
struct dentry *base, int len)
{
return lookup_one(ovl_upper_mnt_userns(ofs), name, base, len);
}
static inline bool ovl_open_flags_need_copy_up(int flags)
{
if (!flags)

6
fs/overlayfs/readdir.c
View File

@ -1013,7 +1013,7 @@ void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
if (WARN_ON(!p->is_whiteout || !p->is_upper))
continue;
dentry = lookup_one_len(p->name, upper, p->len);
dentry = ovl_lookup_upper(ofs, p->name, upper, p->len);
if (IS_ERR(dentry)) {
pr_err("lookup '%s/%.*s' failed (%i)\n",
upper->d_name.name, p->len, p->name,
@ -1113,7 +1113,7 @@ static int ovl_workdir_cleanup_recurse(struct ovl_fs *ofs, struct path *path,
err = -EINVAL;
break;
}
dentry = lookup_one_len(p->name, path->dentry, p->len);
dentry = ovl_lookup_upper(ofs, p->name, path->dentry, p->len);
if (IS_ERR(dentry))
continue;
if (dentry->d_inode)
@ -1181,7 +1181,7 @@ int ovl_indexdir_cleanup(struct ovl_fs *ofs)
if (p->len == 2 && p->name[1] == '.')
continue;
}
index = lookup_one_len(p->name, indexdir, p->len);
index = ovl_lookup_upper(ofs, p->name, indexdir, p->len);
if (IS_ERR(index)) {
err = PTR_ERR(index);
index = NULL;

6
fs/overlayfs/super.c
View File

@ -761,7 +761,7 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
inode_lock_nested(dir, I_MUTEX_PARENT);
retry:
work = lookup_one_len(name, ofs->workbasedir, strlen(name));
work = ovl_lookup_upper(ofs, name, ofs->workbasedir, strlen(name));
if (!IS_ERR(work)) {
struct iattr attr = {
@ -1289,7 +1289,7 @@ static int ovl_check_rename_whiteout(struct ovl_fs *ofs)
goto cleanup_temp;
}
whiteout = lookup_one_len(name.name.name, workdir, name.name.len);
whiteout = ovl_lookup_upper(ofs, name.name.name, workdir, name.name.len);
err = PTR_ERR(whiteout);
if (IS_ERR(whiteout))
goto cleanup_temp;
@ -1321,7 +1321,7 @@ static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs,
struct dentry *child;
inode_lock_nested(parent->d_inode, I_MUTEX_PARENT);
child = lookup_one_len(name, parent, len);
child = ovl_lookup_upper(ofs, name, parent, len);
if (!IS_ERR(child) && !child->d_inode)
child = ovl_create_real(ofs, parent->d_inode, child,
OVL_CATTR(mode));

2
fs/overlayfs/util.c
View File

@ -838,7 +838,7 @@ static void ovl_cleanup_index(struct dentry *dentry)
}
inode_lock_nested(dir, I_MUTEX_PARENT);
index = lookup_one_len(name.name, indexdir, name.len);
index = ovl_lookup_upper(ofs, name.name, indexdir, name.len);
err = PTR_ERR(index);
if (IS_ERR(index)) {
index = NULL;