ovl: introduce struct ovl_renamedata

Add a struct ovl_renamedata to group rename-related state that was
previously stored in local variables. Embedd struct renamedata directly
aligning with the vfs.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://patch.msgid.link/20251117-work-ovl-cred-guard-v4-33-b31603935724@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index ef00fc43ee652dd725809470421c193407f36a01..83f5027cf45de39d28b8fa43aef5475945da741f 100644 (file)
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -1094,6 +1094,14 @@ static int ovl_set_redirect(struct dentry *dentry, bool samedir)
        return err;
 }
 
+struct ovl_renamedata {
+       struct renamedata;
+       struct dentry *opaquedir;
+       bool cleanup_whiteout;
+       bool update_nlink;
+       bool overwrite;
+};
+
 static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
                      struct dentry *old, struct inode *newdir,
                      struct dentry *new, unsigned int flags)
@@ -1104,49 +1112,53 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
        struct renamedata rd = {};
        bool old_opaque;
        bool new_opaque;
-       bool cleanup_whiteout = false;
-       bool update_nlink = false;
-       bool overwrite = !(flags & RENAME_EXCHANGE);
        bool is_dir = d_is_dir(old);
        bool new_is_dir = d_is_dir(new);
-       bool samedir = olddir == newdir;
-       struct dentry *opaquedir = NULL;
+       bool samedir = old->d_parent == new->d_parent;
        struct dentry *whiteout = NULL;
        const struct cred *old_cred = NULL;
        struct ovl_fs *ofs = OVL_FS(old->d_sb);
+       struct ovl_renamedata _ovlrd = {
+               .old_dentry             = old,
+               .new_dentry             = new,
+               .flags                  = flags,
+               .cleanup_whiteout       = false,
+               .overwrite              = !(flags & RENAME_EXCHANGE),
+       };
+       struct ovl_renamedata *ovlrd = &_ovlrd;
        LIST_HEAD(list);
 
        err = -EINVAL;
-       if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
+       if (ovlrd->flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
                goto out;
 
-       flags &= ~RENAME_NOREPLACE;
+       ovlrd->flags &= ~RENAME_NOREPLACE;
 
        /* Don't copy up directory trees */
        err = -EXDEV;
        if (!ovl_can_move(old))
                goto out;
-       if (!overwrite && !ovl_can_move(new))
+       if (!ovlrd->overwrite && !ovl_can_move(new))
                goto out;
 
-       if (overwrite && new_is_dir && !ovl_pure_upper(new)) {
+       if (ovlrd->overwrite && new_is_dir && !ovl_pure_upper(new)) {
                err = ovl_check_empty_dir(new, &list);
                if (err)
                        goto out;
        }
 
-       if (overwrite) {
+       if (ovlrd->overwrite) {
                if (ovl_lower_positive(old)) {
                        if (!ovl_dentry_is_whiteout(new)) {
                                /* Whiteout source */
-                               flags |= RENAME_WHITEOUT;
+                               ovlrd->flags |= RENAME_WHITEOUT;
                        } else {
                                /* Switch whiteouts */
-                               flags |= RENAME_EXCHANGE;
+                               ovlrd->flags |= RENAME_EXCHANGE;
                        }
                } else if (is_dir && ovl_dentry_is_whiteout(new)) {
-                       flags |= RENAME_EXCHANGE;
-                       cleanup_whiteout = true;
+                       ovlrd->flags |= RENAME_EXCHANGE;
+                       ovlrd->cleanup_whiteout = true;
                }
        }
 
@@ -1157,7 +1169,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
        err = ovl_copy_up(new->d_parent);
        if (err)
                goto out;
-       if (!overwrite) {
+       if (!ovlrd->overwrite) {
                err = ovl_copy_up(new);
                if (err)
                        goto out;
@@ -1166,10 +1178,10 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
                if (err)
                        goto out;
 
-               update_nlink = true;
+               ovlrd->update_nlink = true;
        }
 
-       if (!update_nlink) {
+       if (!ovlrd->update_nlink) {
                /* ovl_nlink_start() took ovl_want_write() */
                err = ovl_want_write(old);
                if (err)
@@ -1179,10 +1191,10 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
        old_cred = ovl_override_creds(old->d_sb);
 
        if (!list_empty(&list)) {
-               opaquedir = ovl_clear_empty(new, &list);
-               err = PTR_ERR(opaquedir);
-               if (IS_ERR(opaquedir)) {
-                       opaquedir = NULL;
+               ovlrd->opaquedir = ovl_clear_empty(new, &list);
+               err = PTR_ERR(ovlrd->opaquedir);
+               if (IS_ERR(ovlrd->opaquedir)) {
+                       ovlrd->opaquedir = NULL;
                        goto out_revert_creds;
                }
        }
@@ -1202,7 +1214,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
                        if (err)
                                goto out_revert_creds;
                }
-               if (!overwrite && ovl_type_origin(new)) {
+               if (!ovlrd->overwrite && ovl_type_origin(new)) {
                        err = ovl_set_impure(old->d_parent, old_upperdir);
                        if (err)
                                goto out_revert_creds;
@@ -1212,7 +1224,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
        rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
        rd.old_parent = old_upperdir;
        rd.new_parent = new_upperdir;
-       rd.flags = flags;
+       rd.flags = ovlrd->flags;
 
        err = start_renaming(&rd, 0,
                             &QSTR_LEN(old->d_name.name, old->d_name.len),
@@ -1230,8 +1242,8 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
 
        err = -ESTALE;
        if (d_inode(new) && ovl_dentry_upper(new)) {
-               if (opaquedir) {
-                       if (rd.new_dentry != opaquedir)
+               if (ovlrd->opaquedir) {
+                       if (rd.new_dentry != ovlrd->opaquedir)
                                goto out_unlock;
                } else {
                        if (!ovl_matches_upper(new, rd.new_dentry))
@@ -1242,7 +1254,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
                        if (!new_opaque || !ovl_upper_is_whiteout(ofs, rd.new_dentry))
                                goto out_unlock;
                } else {
-                       if (flags & RENAME_EXCHANGE)
+                       if (ovlrd->flags & RENAME_EXCHANGE)
                                goto out_unlock;
                }
        }
@@ -1258,9 +1270,9 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
        if (err)
                goto out_unlock;
 
-       if (!overwrite && ovl_type_merge_or_lower(new))
+       if (!ovlrd->overwrite && ovl_type_merge_or_lower(new))
                err = ovl_set_redirect(new, samedir);
-       else if (!overwrite && new_is_dir && !new_opaque &&
+       else if (!ovlrd->overwrite && new_is_dir && !new_opaque &&
                 ovl_type_merge(old->d_parent))
                err = ovl_set_opaque_xerr(new, rd.new_dentry, -EXDEV);
        if (err)
@@ -1268,7 +1280,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
 
        err = ovl_do_rename_rd(&rd);
 
-       if (!err && cleanup_whiteout)
+       if (!err && ovlrd->cleanup_whiteout)
                whiteout = dget(rd.new_dentry);
 
        end_renaming(&rd);
@@ -1281,7 +1293,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
                dput(whiteout);
        }
 
-       if (overwrite && d_inode(new)) {
+       if (ovlrd->overwrite && d_inode(new)) {
                if (new_is_dir)
                        clear_nlink(d_inode(new));
                else
@@ -1289,7 +1301,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
        }
 
        ovl_dir_modified(old->d_parent, ovl_type_origin(old) ||
-                        (!overwrite && ovl_type_origin(new)));
+                        (!ovlrd->overwrite && ovl_type_origin(new)));
        ovl_dir_modified(new->d_parent, ovl_type_origin(old) ||
                         (d_inode(new) && ovl_type_origin(new)));
 
@@ -1300,12 +1312,12 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
 
 out_revert_creds:
        ovl_revert_creds(old_cred);
-       if (update_nlink)
+       if (ovlrd->update_nlink)
                ovl_nlink_end(new);
        else
                ovl_drop_write(old);
 out:
-       dput(opaquedir);
+       dput(ovlrd->opaquedir);
        ovl_cache_free(&list);
        return err;