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ovl: clean up kstat usage
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FWIW, there's a bit of abuse of struct kstat in overlayfs object
creation paths - for one thing, it ends up with a very small subset
of struct kstat (mode + rdev), for another it also needs link in
case of symlinks and ends up passing it separately.

IMO it would be better to introduce a separate object for that.

In principle, we might even lift that thing into general API and switch
 ->mkdir()/->mknod()/->symlink() to identical calling conventions.  Hell
knows, perhaps ->create() as well...

Signed-off-by: Miklos Szeredi <[email protected]>
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Al Viro authored and Miklos Szeredi committed Dec 16, 2016
1 parent 9aba652 commit 32a3d84
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Showing 4 changed files with 45 additions and 39 deletions.
12 changes: 7 additions & 5 deletions fs/overlayfs/copy_up.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -238,10 +238,15 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
struct inode *udir = upperdir->d_inode;
struct dentry *newdentry = NULL;
struct dentry *upper = NULL;
umode_t mode = stat->mode;
int err;
const struct cred *old_creds = NULL;
struct cred *new_creds = NULL;
struct cattr cattr = {
/* Can't properly set mode on creation because of the umask */
.mode = stat->mode & S_IFMT,
.rdev = stat->rdev,
.link = link
};

newdentry = ovl_lookup_temp(workdir, dentry);
err = PTR_ERR(newdentry);
Expand All @@ -261,10 +266,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
if (new_creds)
old_creds = override_creds(new_creds);

/* Can't properly set mode on creation because of the umask */
stat->mode &= S_IFMT;
err = ovl_create_real(wdir, newdentry, stat, link, NULL, true);
stat->mode = mode;
err = ovl_create_real(wdir, newdentry, &cattr, NULL, true);

if (new_creds) {
revert_creds(old_creds);
Expand Down
56 changes: 28 additions & 28 deletions fs/overlayfs/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -82,8 +82,7 @@ static struct dentry *ovl_whiteout(struct dentry *workdir,
}

int ovl_create_real(struct inode *dir, struct dentry *newdentry,
struct kstat *stat, const char *link,
struct dentry *hardlink, bool debug)
struct cattr *attr, struct dentry *hardlink, bool debug)
{
int err;

Expand All @@ -93,25 +92,25 @@ int ovl_create_real(struct inode *dir, struct dentry *newdentry,
if (hardlink) {
err = ovl_do_link(hardlink, dir, newdentry, debug);
} else {
switch (stat->mode & S_IFMT) {
switch (attr->mode & S_IFMT) {
case S_IFREG:
err = ovl_do_create(dir, newdentry, stat->mode, debug);
err = ovl_do_create(dir, newdentry, attr->mode, debug);
break;

case S_IFDIR:
err = ovl_do_mkdir(dir, newdentry, stat->mode, debug);
err = ovl_do_mkdir(dir, newdentry, attr->mode, debug);
break;

case S_IFCHR:
case S_IFBLK:
case S_IFIFO:
case S_IFSOCK:
err = ovl_do_mknod(dir, newdentry,
stat->mode, stat->rdev, debug);
attr->mode, attr->rdev, debug);
break;

case S_IFLNK:
err = ovl_do_symlink(dir, newdentry, link, debug);
err = ovl_do_symlink(dir, newdentry, attr->link, debug);
break;

default:
Expand Down Expand Up @@ -190,24 +189,23 @@ static bool ovl_type_merge(struct dentry *dentry)
}

static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
struct kstat *stat, const char *link,
struct dentry *hardlink)
struct cattr *attr, struct dentry *hardlink)
{
struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
struct inode *udir = upperdir->d_inode;
struct dentry *newdentry;
int err;

if (!hardlink && !IS_POSIXACL(udir))
stat->mode &= ~current_umask();
attr->mode &= ~current_umask();

inode_lock_nested(udir, I_MUTEX_PARENT);
newdentry = lookup_one_len(dentry->d_name.name, upperdir,
dentry->d_name.len);
err = PTR_ERR(newdentry);
if (IS_ERR(newdentry))
goto out_unlock;
err = ovl_create_real(udir, newdentry, stat, link, hardlink, false);
err = ovl_create_real(udir, newdentry, attr, hardlink, false);
if (err)
goto out_dput;

Expand Down Expand Up @@ -282,7 +280,8 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
if (IS_ERR(opaquedir))
goto out_unlock;

err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true);
err = ovl_create_real(wdir, opaquedir,
&(struct cattr){.mode = stat.mode}, NULL, true);
if (err)
goto out_dput;

Expand Down Expand Up @@ -382,7 +381,7 @@ static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
}

static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
struct kstat *stat, const char *link,
struct cattr *cattr,
struct dentry *hardlink)
{
struct dentry *workdir = ovl_workdir(dentry);
Expand All @@ -399,7 +398,7 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,

if (!hardlink) {
err = posix_acl_create(dentry->d_parent->d_inode,
&stat->mode, &default_acl, &acl);
&cattr->mode, &default_acl, &acl);
if (err)
return err;
}
Expand All @@ -419,18 +418,19 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
if (IS_ERR(upper))
goto out_dput;

err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
err = ovl_create_real(wdir, newdentry, cattr, hardlink, true);
if (err)
goto out_dput2;

/*
* mode could have been mutilated due to umask (e.g. sgid directory)
*/
if (!hardlink &&
!S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) {
!S_ISLNK(cattr->mode) &&
newdentry->d_inode->i_mode != cattr->mode) {
struct iattr attr = {
.ia_valid = ATTR_MODE,
.ia_mode = stat->mode,
.ia_mode = cattr->mode,
};
inode_lock(newdentry->d_inode);
err = notify_change(newdentry, &attr, NULL);
Expand All @@ -450,7 +450,7 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
goto out_cleanup;
}

if (!hardlink && S_ISDIR(stat->mode)) {
if (!hardlink && S_ISDIR(cattr->mode)) {
err = ovl_set_opaque(dentry, newdentry);
if (err)
goto out_cleanup;
Expand Down Expand Up @@ -487,8 +487,7 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
}

static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
struct kstat *stat, const char *link,
struct dentry *hardlink)
struct cattr *attr, struct dentry *hardlink)
{
int err;
const struct cred *old_cred;
Expand All @@ -506,7 +505,7 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
override_cred->fsgid = inode->i_gid;
if (!hardlink) {
err = security_dentry_create_files_as(dentry,
stat->mode, &dentry->d_name, old_cred,
attr->mode, &dentry->d_name, old_cred,
override_cred);
if (err) {
put_cred(override_cred);
Expand All @@ -517,11 +516,11 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
put_cred(override_cred);

if (!ovl_dentry_is_whiteout(dentry))
err = ovl_create_upper(dentry, inode, stat, link,
err = ovl_create_upper(dentry, inode, attr,
hardlink);
else
err = ovl_create_over_whiteout(dentry, inode, stat,
link, hardlink);
err = ovl_create_over_whiteout(dentry, inode, attr,
hardlink);
}
out_revert_creds:
revert_creds(old_cred);
Expand All @@ -540,8 +539,9 @@ static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
{
int err;
struct inode *inode;
struct kstat stat = {
struct cattr attr = {
.rdev = rdev,
.link = link,
};

err = ovl_want_write(dentry);
Expand All @@ -554,9 +554,9 @@ static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
goto out_drop_write;

inode_init_owner(inode, dentry->d_parent->d_inode, mode);
stat.mode = inode->i_mode;
attr.mode = inode->i_mode;

err = ovl_create_or_link(dentry, inode, &stat, link, NULL);
err = ovl_create_or_link(dentry, inode, &attr, NULL);
if (err)
iput(inode);

Expand Down Expand Up @@ -610,7 +610,7 @@ static int ovl_link(struct dentry *old, struct inode *newdir,
inode = d_inode(old);
ihold(inode);

err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old));
err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old));
if (err)
iput(inode);

Expand Down
7 changes: 6 additions & 1 deletion fs/overlayfs/overlayfs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -212,8 +212,13 @@ static inline void ovl_copyattr(struct inode *from, struct inode *to)
/* dir.c */
extern const struct inode_operations ovl_dir_inode_operations;
struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry);
struct cattr {
dev_t rdev;
umode_t mode;
const char *link;
};
int ovl_create_real(struct inode *dir, struct dentry *newdentry,
struct kstat *stat, const char *link,
struct cattr *attr,
struct dentry *hardlink, bool debug);
void ovl_cleanup(struct inode *dir, struct dentry *dentry);

Expand Down
9 changes: 4 additions & 5 deletions fs/overlayfs/super.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -354,12 +354,9 @@ static struct dentry *ovl_workdir_create(struct vfsmount *mnt,
strlen(OVL_WORKDIR_NAME));

if (!IS_ERR(work)) {
struct kstat stat = {
.mode = S_IFDIR | 0,
};
struct iattr attr = {
.ia_valid = ATTR_MODE,
.ia_mode = stat.mode,
.ia_mode = S_IFDIR | 0,
};

if (work->d_inode) {
Expand All @@ -373,7 +370,9 @@ static struct dentry *ovl_workdir_create(struct vfsmount *mnt,
goto retry;
}

err = ovl_create_real(dir, work, &stat, NULL, NULL, true);
err = ovl_create_real(dir, work,
&(struct cattr){.mode = S_IFDIR | 0},
NULL, true);
if (err)
goto out_dput;

Expand Down

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