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-rw-r--r--fs/overlayfs/dir.c928
1 files changed, 928 insertions, 0 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
new file mode 100644
index 000000000000..0dc4c33a0a1b
--- /dev/null
+++ b/fs/overlayfs/dir.c
@@ -0,0 +1,928 @@
+/*
+ *
+ * Copyright (C) 2011 Novell Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/xattr.h>
+#include <linux/security.h>
+#include <linux/cred.h>
+#include "overlayfs.h"
+
+void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
+{
+ int err;
+
+ dget(wdentry);
+ if (S_ISDIR(wdentry->d_inode->i_mode))
+ err = ovl_do_rmdir(wdir, wdentry);
+ else
+ err = ovl_do_unlink(wdir, wdentry);
+ dput(wdentry);
+
+ if (err) {
+ pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
+ wdentry, err);
+ }
+}
+
+struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry)
+{
+ struct dentry *temp;
+ char name[20];
+
+ snprintf(name, sizeof(name), "#%lx", (unsigned long) dentry);
+
+ temp = lookup_one_len(name, workdir, strlen(name));
+ if (!IS_ERR(temp) && temp->d_inode) {
+ pr_err("overlayfs: workdir/%s already exists\n", name);
+ dput(temp);
+ temp = ERR_PTR(-EIO);
+ }
+
+ return temp;
+}
+
+/* caller holds i_mutex on workdir */
+static struct dentry *ovl_whiteout(struct dentry *workdir,
+ struct dentry *dentry)
+{
+ int err;
+ struct dentry *whiteout;
+ struct inode *wdir = workdir->d_inode;
+
+ whiteout = ovl_lookup_temp(workdir, dentry);
+ if (IS_ERR(whiteout))
+ return whiteout;
+
+ err = ovl_do_whiteout(wdir, whiteout);
+ if (err) {
+ dput(whiteout);
+ whiteout = ERR_PTR(err);
+ }
+
+ return whiteout;
+}
+
+int ovl_create_real(struct inode *dir, struct dentry *newdentry,
+ struct kstat *stat, const char *link,
+ struct dentry *hardlink, bool debug)
+{
+ int err;
+
+ if (newdentry->d_inode)
+ return -ESTALE;
+
+ if (hardlink) {
+ err = ovl_do_link(hardlink, dir, newdentry, debug);
+ } else {
+ switch (stat->mode & S_IFMT) {
+ case S_IFREG:
+ err = ovl_do_create(dir, newdentry, stat->mode, debug);
+ break;
+
+ case S_IFDIR:
+ err = ovl_do_mkdir(dir, newdentry, stat->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);
+ break;
+
+ case S_IFLNK:
+ err = ovl_do_symlink(dir, newdentry, link, debug);
+ break;
+
+ default:
+ err = -EPERM;
+ }
+ }
+ if (!err && WARN_ON(!newdentry->d_inode)) {
+ /*
+ * Not quite sure if non-instantiated dentry is legal or not.
+ * VFS doesn't seem to care so check and warn here.
+ */
+ err = -ENOENT;
+ }
+ return err;
+}
+
+static int ovl_set_opaque(struct dentry *upperdentry)
+{
+ return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
+}
+
+static void ovl_remove_opaque(struct dentry *upperdentry)
+{
+ int err;
+
+ err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE);
+ if (err) {
+ pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
+ upperdentry->d_name.name, err);
+ }
+}
+
+static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
+ struct kstat *stat)
+{
+ int err;
+ enum ovl_path_type type;
+ struct path realpath;
+
+ type = ovl_path_real(dentry, &realpath);
+ err = vfs_getattr(&realpath, stat);
+ if (err)
+ return err;
+
+ stat->dev = dentry->d_sb->s_dev;
+ stat->ino = dentry->d_inode->i_ino;
+
+ /*
+ * It's probably not worth it to count subdirs to get the
+ * correct link count. nlink=1 seems to pacify 'find' and
+ * other utilities.
+ */
+ if (OVL_TYPE_MERGE(type))
+ stat->nlink = 1;
+
+ return 0;
+}
+
+static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
+ struct kstat *stat, const char *link,
+ struct dentry *hardlink)
+{
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *udir = upperdir->d_inode;
+ struct dentry *newdentry;
+ int err;
+
+ mutex_lock_nested(&udir->i_mutex, 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);
+ if (err)
+ goto out_dput;
+
+ ovl_dentry_version_inc(dentry->d_parent);
+ ovl_dentry_update(dentry, newdentry);
+ ovl_copyattr(newdentry->d_inode, inode);
+ d_instantiate(dentry, inode);
+ newdentry = NULL;
+out_dput:
+ dput(newdentry);
+out_unlock:
+ mutex_unlock(&udir->i_mutex);
+ return err;
+}
+
+static int ovl_lock_rename_workdir(struct dentry *workdir,
+ struct dentry *upperdir)
+{
+ /* Workdir should not be the same as upperdir */
+ if (workdir == upperdir)
+ goto err;
+
+ /* Workdir should not be subdir of upperdir and vice versa */
+ if (lock_rename(workdir, upperdir) != NULL)
+ goto err_unlock;
+
+ return 0;
+
+err_unlock:
+ unlock_rename(workdir, upperdir);
+err:
+ pr_err("overlayfs: failed to lock workdir+upperdir\n");
+ return -EIO;
+}
+
+static struct dentry *ovl_clear_empty(struct dentry *dentry,
+ struct list_head *list)
+{
+ struct dentry *workdir = ovl_workdir(dentry);
+ struct inode *wdir = workdir->d_inode;
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *udir = upperdir->d_inode;
+ struct path upperpath;
+ struct dentry *upper;
+ struct dentry *opaquedir;
+ struct kstat stat;
+ int err;
+
+ err = ovl_lock_rename_workdir(workdir, upperdir);
+ if (err)
+ goto out;
+
+ ovl_path_upper(dentry, &upperpath);
+ err = vfs_getattr(&upperpath, &stat);
+ if (err)
+ goto out_unlock;
+
+ err = -ESTALE;
+ if (!S_ISDIR(stat.mode))
+ goto out_unlock;
+ upper = upperpath.dentry;
+ if (upper->d_parent->d_inode != udir)
+ goto out_unlock;
+
+ opaquedir = ovl_lookup_temp(workdir, dentry);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir))
+ goto out_unlock;
+
+ err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true);
+ if (err)
+ goto out_dput;
+
+ err = ovl_copy_xattr(upper, opaquedir);
+ if (err)
+ goto out_cleanup;
+
+ err = ovl_set_opaque(opaquedir);
+ if (err)
+ goto out_cleanup;
+
+ mutex_lock(&opaquedir->d_inode->i_mutex);
+ err = ovl_set_attr(opaquedir, &stat);
+ mutex_unlock(&opaquedir->d_inode->i_mutex);
+ if (err)
+ goto out_cleanup;
+
+ err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
+ if (err)
+ goto out_cleanup;
+
+ ovl_cleanup_whiteouts(upper, list);
+ ovl_cleanup(wdir, upper);
+ unlock_rename(workdir, upperdir);
+
+ /* dentry's upper doesn't match now, get rid of it */
+ d_drop(dentry);
+
+ return opaquedir;
+
+out_cleanup:
+ ovl_cleanup(wdir, opaquedir);
+out_dput:
+ dput(opaquedir);
+out_unlock:
+ unlock_rename(workdir, upperdir);
+out:
+ return ERR_PTR(err);
+}
+
+static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
+{
+ int err;
+ struct dentry *ret = NULL;
+ LIST_HEAD(list);
+
+ err = ovl_check_empty_dir(dentry, &list);
+ if (err)
+ ret = ERR_PTR(err);
+ else {
+ /*
+ * If no upperdentry then skip clearing whiteouts.
+ *
+ * Can race with copy-up, since we don't hold the upperdir
+ * mutex. Doesn't matter, since copy-up can't create a
+ * non-empty directory from an empty one.
+ */
+ if (ovl_dentry_upper(dentry))
+ ret = ovl_clear_empty(dentry, &list);
+ }
+
+ ovl_cache_free(&list);
+
+ return ret;
+}
+
+static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
+ struct kstat *stat, const char *link,
+ struct dentry *hardlink)
+{
+ struct dentry *workdir = ovl_workdir(dentry);
+ struct inode *wdir = workdir->d_inode;
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *udir = upperdir->d_inode;
+ struct dentry *upper;
+ struct dentry *newdentry;
+ int err;
+
+ err = ovl_lock_rename_workdir(workdir, upperdir);
+ if (err)
+ goto out;
+
+ newdentry = ovl_lookup_temp(workdir, dentry);
+ err = PTR_ERR(newdentry);
+ if (IS_ERR(newdentry))
+ goto out_unlock;
+
+ upper = lookup_one_len(dentry->d_name.name, upperdir,
+ dentry->d_name.len);
+ err = PTR_ERR(upper);
+ if (IS_ERR(upper))
+ goto out_dput;
+
+ err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
+ if (err)
+ goto out_dput2;
+
+ if (S_ISDIR(stat->mode)) {
+ err = ovl_set_opaque(newdentry);
+ if (err)
+ goto out_cleanup;
+
+ err = ovl_do_rename(wdir, newdentry, udir, upper,
+ RENAME_EXCHANGE);
+ if (err)
+ goto out_cleanup;
+
+ ovl_cleanup(wdir, upper);
+ } else {
+ err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
+ if (err)
+ goto out_cleanup;
+ }
+ ovl_dentry_version_inc(dentry->d_parent);
+ ovl_dentry_update(dentry, newdentry);
+ ovl_copyattr(newdentry->d_inode, inode);
+ d_instantiate(dentry, inode);
+ newdentry = NULL;
+out_dput2:
+ dput(upper);
+out_dput:
+ dput(newdentry);
+out_unlock:
+ unlock_rename(workdir, upperdir);
+out:
+ return err;
+
+out_cleanup:
+ ovl_cleanup(wdir, newdentry);
+ goto out_dput2;
+}
+
+static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev,
+ const char *link, struct dentry *hardlink)
+{
+ int err;
+ struct inode *inode;
+ struct kstat stat = {
+ .mode = mode,
+ .rdev = rdev,
+ };
+
+ err = -ENOMEM;
+ inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata);
+ if (!inode)
+ goto out;
+
+ err = ovl_copy_up(dentry->d_parent);
+ if (err)
+ goto out_iput;
+
+ if (!ovl_dentry_is_opaque(dentry)) {
+ err = ovl_create_upper(dentry, inode, &stat, link, hardlink);
+ } else {
+ const struct cred *old_cred;
+ struct cred *override_cred;
+
+ err = -ENOMEM;
+ override_cred = prepare_creds();
+ if (!override_cred)
+ goto out_iput;
+
+ /*
+ * CAP_SYS_ADMIN for setting opaque xattr
+ * CAP_DAC_OVERRIDE for create in workdir, rename
+ * CAP_FOWNER for removing whiteout from sticky dir
+ */
+ cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
+ cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
+ cap_raise(override_cred->cap_effective, CAP_FOWNER);
+ old_cred = override_creds(override_cred);
+
+ err = ovl_create_over_whiteout(dentry, inode, &stat, link,
+ hardlink);
+
+ revert_creds(old_cred);
+ put_cred(override_cred);
+ }
+
+ if (!err)
+ inode = NULL;
+out_iput:
+ iput(inode);
+out:
+ return err;
+}
+
+static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
+ const char *link)
+{
+ int err;
+
+ err = ovl_want_write(dentry);
+ if (!err) {
+ err = ovl_create_or_link(dentry, mode, rdev, link, NULL);
+ ovl_drop_write(dentry);
+ }
+
+ return err;
+}
+
+static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+ bool excl)
+{
+ return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
+}
+
+static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+ return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
+}
+
+static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
+ dev_t rdev)
+{
+ /* Don't allow creation of "whiteout" on overlay */
+ if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
+ return -EPERM;
+
+ return ovl_create_object(dentry, mode, rdev, NULL);
+}
+
+static int ovl_symlink(struct inode *dir, struct dentry *dentry,
+ const char *link)
+{
+ return ovl_create_object(dentry, S_IFLNK, 0, link);
+}
+
+static int ovl_link(struct dentry *old, struct inode *newdir,
+ struct dentry *new)
+{
+ int err;
+ struct dentry *upper;
+
+ err = ovl_want_write(old);
+ if (err)
+ goto out;
+
+ err = ovl_copy_up(old);
+ if (err)
+ goto out_drop_write;
+
+ upper = ovl_dentry_upper(old);
+ err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper);
+
+out_drop_write:
+ ovl_drop_write(old);
+out:
+ return err;
+}
+
+static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
+{
+ struct dentry *workdir = ovl_workdir(dentry);
+ struct inode *wdir = workdir->d_inode;
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *udir = upperdir->d_inode;
+ struct dentry *whiteout;
+ struct dentry *upper;
+ struct dentry *opaquedir = NULL;
+ int err;
+
+ if (is_dir && OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
+ opaquedir = ovl_check_empty_and_clear(dentry);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir))
+ goto out;
+ }
+
+ err = ovl_lock_rename_workdir(workdir, upperdir);
+ if (err)
+ goto out_dput;
+
+ whiteout = ovl_whiteout(workdir, dentry);
+ err = PTR_ERR(whiteout);
+ if (IS_ERR(whiteout))
+ goto out_unlock;
+
+ upper = ovl_dentry_upper(dentry);
+ if (!upper) {
+ upper = lookup_one_len(dentry->d_name.name, upperdir,
+ dentry->d_name.len);
+ err = PTR_ERR(upper);
+ if (IS_ERR(upper))
+ goto kill_whiteout;
+
+ err = ovl_do_rename(wdir, whiteout, udir, upper, 0);
+ dput(upper);
+ if (err)
+ goto kill_whiteout;
+ } else {
+ int flags = 0;
+
+ if (opaquedir)
+ upper = opaquedir;
+ err = -ESTALE;
+ if (upper->d_parent != upperdir)
+ goto kill_whiteout;
+
+ if (is_dir)
+ flags |= RENAME_EXCHANGE;
+
+ err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
+ if (err)
+ goto kill_whiteout;
+
+ if (is_dir)
+ ovl_cleanup(wdir, upper);
+ }
+ ovl_dentry_version_inc(dentry->d_parent);
+out_d_drop:
+ d_drop(dentry);
+ dput(whiteout);
+out_unlock:
+ unlock_rename(workdir, upperdir);
+out_dput:
+ dput(opaquedir);
+out:
+ return err;
+
+kill_whiteout:
+ ovl_cleanup(wdir, whiteout);
+ goto out_d_drop;
+}
+
+static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
+{
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *dir = upperdir->d_inode;
+ struct dentry *upper = ovl_dentry_upper(dentry);
+ int err;
+
+ mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
+ err = -ESTALE;
+ if (upper->d_parent == upperdir) {
+ /* Don't let d_delete() think it can reset d_inode */
+ dget(upper);
+ if (is_dir)
+ err = vfs_rmdir(dir, upper);
+ else
+ err = vfs_unlink(dir, upper, NULL);
+ dput(upper);
+ ovl_dentry_version_inc(dentry->d_parent);
+ }
+
+ /*
+ * Keeping this dentry hashed would mean having to release
+ * upperpath/lowerpath, which could only be done if we are the
+ * sole user of this dentry. Too tricky... Just unhash for
+ * now.
+ */
+ d_drop(dentry);
+ mutex_unlock(&dir->i_mutex);
+
+ return err;
+}
+
+static inline int ovl_check_sticky(struct dentry *dentry)
+{
+ struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode;
+ struct inode *inode = ovl_dentry_real(dentry)->d_inode;
+
+ if (check_sticky(dir, inode))
+ return -EPERM;
+
+ return 0;
+}
+
+static int ovl_do_remove(struct dentry *dentry, bool is_dir)
+{
+ enum ovl_path_type type;
+ int err;
+
+ err = ovl_check_sticky(dentry);
+ if (err)
+ goto out;
+
+ err = ovl_want_write(dentry);
+ if (err)
+ goto out;
+
+ err = ovl_copy_up(dentry->d_parent);
+ if (err)
+ goto out_drop_write;
+
+ type = ovl_path_type(dentry);
+ if (OVL_TYPE_PURE_UPPER(type)) {
+ err = ovl_remove_upper(dentry, is_dir);
+ } else {
+ const struct cred *old_cred;
+ struct cred *override_cred;
+
+ err = -ENOMEM;
+ override_cred = prepare_creds();
+ if (!override_cred)
+ goto out_drop_write;
+
+ /*
+ * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir
+ * CAP_DAC_OVERRIDE for create in workdir, rename
+ * CAP_FOWNER for removing whiteout from sticky dir
+ * CAP_FSETID for chmod of opaque dir
+ * CAP_CHOWN for chown of opaque dir
+ */
+ cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
+ cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
+ cap_raise(override_cred->cap_effective, CAP_FOWNER);
+ cap_raise(override_cred->cap_effective, CAP_FSETID);
+ cap_raise(override_cred->cap_effective, CAP_CHOWN);
+ old_cred = override_creds(override_cred);
+
+ err = ovl_remove_and_whiteout(dentry, is_dir);
+
+ revert_creds(old_cred);
+ put_cred(override_cred);
+ }
+out_drop_write:
+ ovl_drop_write(dentry);
+out:
+ return err;
+}
+
+static int ovl_unlink(struct inode *dir, struct dentry *dentry)
+{
+ return ovl_do_remove(dentry, false);
+}
+
+static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ return ovl_do_remove(dentry, true);
+}
+
+static int ovl_rename2(struct inode *olddir, struct dentry *old,
+ struct inode *newdir, struct dentry *new,
+ unsigned int flags)
+{
+ int err;
+ enum ovl_path_type old_type;
+ enum ovl_path_type new_type;
+ struct dentry *old_upperdir;
+ struct dentry *new_upperdir;
+ struct dentry *olddentry;
+ struct dentry *newdentry;
+ struct dentry *trap;
+ bool old_opaque;
+ bool new_opaque;
+ bool new_create = false;
+ bool cleanup_whiteout = false;
+ bool overwrite = !(flags & RENAME_EXCHANGE);
+ bool is_dir = S_ISDIR(old->d_inode->i_mode);
+ bool new_is_dir = false;
+ struct dentry *opaquedir = NULL;
+ const struct cred *old_cred = NULL;
+ struct cred *override_cred = NULL;
+
+ err = -EINVAL;
+ if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
+ goto out;
+
+ flags &= ~RENAME_NOREPLACE;
+
+ err = ovl_check_sticky(old);
+ if (err)
+ goto out;
+
+ /* Don't copy up directory trees */
+ old_type = ovl_path_type(old);
+ err = -EXDEV;
+ if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
+ goto out;
+
+ if (new->d_inode) {
+ err = ovl_check_sticky(new);
+ if (err)
+ goto out;
+
+ if (S_ISDIR(new->d_inode->i_mode))
+ new_is_dir = true;
+
+ new_type = ovl_path_type(new);
+ err = -EXDEV;
+ if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
+ goto out;
+
+ err = 0;
+ if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) {
+ if (ovl_dentry_lower(old)->d_inode ==
+ ovl_dentry_lower(new)->d_inode)
+ goto out;
+ }
+ if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) {
+ if (ovl_dentry_upper(old)->d_inode ==
+ ovl_dentry_upper(new)->d_inode)
+ goto out;
+ }
+ } else {
+ if (ovl_dentry_is_opaque(new))
+ new_type = __OVL_PATH_UPPER;
+ else
+ new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE;
+ }
+
+ err = ovl_want_write(old);
+ if (err)
+ goto out;
+
+ err = ovl_copy_up(old);
+ if (err)
+ goto out_drop_write;
+
+ err = ovl_copy_up(new->d_parent);
+ if (err)
+ goto out_drop_write;
+ if (!overwrite) {
+ err = ovl_copy_up(new);
+ if (err)
+ goto out_drop_write;
+ }
+
+ old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
+ new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
+
+ if (old_opaque || new_opaque) {
+ err = -ENOMEM;
+ override_cred = prepare_creds();
+ if (!override_cred)
+ goto out_drop_write;
+
+ /*
+ * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir
+ * CAP_DAC_OVERRIDE for create in workdir
+ * CAP_FOWNER for removing whiteout from sticky dir
+ * CAP_FSETID for chmod of opaque dir
+ * CAP_CHOWN for chown of opaque dir
+ */
+ cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
+ cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
+ cap_raise(override_cred->cap_effective, CAP_FOWNER);
+ cap_raise(override_cred->cap_effective, CAP_FSETID);
+ cap_raise(override_cred->cap_effective, CAP_CHOWN);
+ old_cred = override_creds(override_cred);
+ }
+
+ if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
+ opaquedir = ovl_check_empty_and_clear(new);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir)) {
+ opaquedir = NULL;
+ goto out_revert_creds;
+ }
+ }
+
+ if (overwrite) {
+ if (old_opaque) {
+ if (new->d_inode || !new_opaque) {
+ /* Whiteout source */
+ flags |= RENAME_WHITEOUT;
+ } else {
+ /* Switch whiteouts */
+ flags |= RENAME_EXCHANGE;
+ }
+ } else if (is_dir && !new->d_inode && new_opaque) {
+ flags |= RENAME_EXCHANGE;
+ cleanup_whiteout = true;
+ }
+ }
+
+ old_upperdir = ovl_dentry_upper(old->d_parent);
+ new_upperdir = ovl_dentry_upper(new->d_parent);
+
+ trap = lock_rename(new_upperdir, old_upperdir);
+
+ olddentry = ovl_dentry_upper(old);
+ newdentry = ovl_dentry_upper(new);
+ if (newdentry) {
+ if (opaquedir) {
+ newdentry = opaquedir;
+ opaquedir = NULL;
+ } else {
+ dget(newdentry);
+ }
+ } else {
+ new_create = true;
+ newdentry = lookup_one_len(new->d_name.name, new_upperdir,
+ new->d_name.len);
+ err = PTR_ERR(newdentry);
+ if (IS_ERR(newdentry))
+ goto out_unlock;
+ }
+
+ err = -ESTALE;
+ if (olddentry->d_parent != old_upperdir)
+ goto out_dput;
+ if (newdentry->d_parent != new_upperdir)
+ goto out_dput;
+ if (olddentry == trap)
+ goto out_dput;
+ if (newdentry == trap)
+ goto out_dput;
+
+ if (is_dir && !old_opaque && new_opaque) {
+ err = ovl_set_opaque(olddentry);
+ if (err)
+ goto out_dput;
+ }
+ if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
+ err = ovl_set_opaque(newdentry);
+ if (err)
+ goto out_dput;
+ }
+
+ if (old_opaque || new_opaque) {
+ err = ovl_do_rename(old_upperdir->d_inode, olddentry,
+ new_upperdir->d_inode, newdentry,
+ flags);
+ } else {
+ /* No debug for the plain case */
+ BUG_ON(flags & ~RENAME_EXCHANGE);
+ err = vfs_rename(old_upperdir->d_inode, olddentry,
+ new_upperdir->d_inode, newdentry,
+ NULL, flags);
+ }
+
+ if (err) {
+ if (is_dir && !old_opaque && new_opaque)
+ ovl_remove_opaque(olddentry);
+ if (!overwrite && new_is_dir && old_opaque && !new_opaque)
+ ovl_remove_opaque(newdentry);
+ goto out_dput;
+ }
+
+ if (is_dir && old_opaque && !new_opaque)
+ ovl_remove_opaque(olddentry);
+ if (!overwrite && new_is_dir && !old_opaque && new_opaque)
+ ovl_remove_opaque(newdentry);
+
+ if (old_opaque != new_opaque) {
+ ovl_dentry_set_opaque(old, new_opaque);
+ if (!overwrite)
+ ovl_dentry_set_opaque(new, old_opaque);
+ }
+
+ if (cleanup_whiteout)
+ ovl_cleanup(old_upperdir->d_inode, newdentry);
+
+ ovl_dentry_version_inc(old->d_parent);
+ ovl_dentry_version_inc(new->d_parent);
+
+out_dput:
+ dput(newdentry);
+out_unlock:
+ unlock_rename(new_upperdir, old_upperdir);
+out_revert_creds:
+ if (old_opaque || new_opaque) {
+ revert_creds(old_cred);
+ put_cred(override_cred);
+ }
+out_drop_write:
+ ovl_drop_write(old);
+out:
+ dput(opaquedir);
+ return err;
+}
+
+const struct inode_operations ovl_dir_inode_operations = {
+ .lookup = ovl_lookup,
+ .mkdir = ovl_mkdir,
+ .symlink = ovl_symlink,
+ .unlink = ovl_unlink,
+ .rmdir = ovl_rmdir,
+ .rename2 = ovl_rename2,
+ .link = ovl_link,
+ .setattr = ovl_setattr,
+ .create = ovl_create,
+ .mknod = ovl_mknod,
+ .permission = ovl_permission,
+ .getattr = ovl_dir_getattr,
+ .setxattr = ovl_setxattr,
+ .getxattr = ovl_getxattr,
+ .listxattr = ovl_listxattr,
+ .removexattr = ovl_removexattr,
+};
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-27 17:28:47 +0000