ovl: clean up kstat usage

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 <mszeredi@redhat.com>

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index e8cacf7a8dccd9ff1dafe3f3a0371367ad267ba6..0e9940f9f34abcc3e6bbddc2e01d0471aa62232d 100644 (file)
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -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);
@@ -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);

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 3cc65e60df02bc9882fd120359b0306cf4b0ddad..16e06dd894575900f0043f417c5bf6227b690cf9 100644 (file)
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -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;
 
@@ -93,13 +92,13 @@ 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:
@@ -107,11 +106,11 @@ int ovl_create_real(struct inode *dir, struct dentry *newdentry,
                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:
@@ -190,8 +189,7 @@ 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;
@@ -199,7 +197,7 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
        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,
@@ -207,7 +205,7 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
        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;
 
@@ -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;
 
@@ -382,7 +381,7 @@ out_free:
 }
 
 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);
@@ -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;
        }
@@ -419,7 +418,7 @@ 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;
 
@@ -427,10 +426,11 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
         * 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);
@@ -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;
@@ -487,8 +487,7 @@ out_cleanup:
 }
 
 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;
@@ -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);
@@ -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);
@@ -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);
@@ -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);
 
@@ -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);
 

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index e07aa7b0ddb7a3e4ca8bbc9901b89209c649eb5a..8af450b0e57a2d826f289d87a1ace6db2d8e7d73 100644 (file)
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -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);
 

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 4bd1e9c7246f6cff10fba6245cdbdd233e8fb66b..7da36ccda438cd0535113f26a23d5641d56d179f 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -354,12 +354,9 @@ retry:
                              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) {
@@ -373,7 +370,9 @@ retry:
                        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;