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firmware/br-ext-chip-allwinner/board/v83x/kernel/patches/00000-fs_sdcardfs_inode.c.p...

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diff -drupN a/fs/sdcardfs/inode.c b/fs/sdcardfs/inode.c
--- a/fs/sdcardfs/inode.c 1970-01-01 03:00:00.000000000 +0300
+++ b/fs/sdcardfs/inode.c 2022-06-12 05:28:14.000000000 +0300
@@ -0,0 +1,818 @@
+/*
+ * fs/sdcardfs/inode.c
+ *
+ * Copyright (c) 2013 Samsung Electronics Co. Ltd
+ * Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
+ * Sunghwan Yun, Sungjong Seo
+ *
+ * This program has been developed as a stackable file system based on
+ * the WrapFS which written by
+ *
+ * Copyright (c) 1998-2011 Erez Zadok
+ * Copyright (c) 2009 Shrikar Archak
+ * Copyright (c) 2003-2011 Stony Brook University
+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
+ *
+ * This file is dual licensed. It may be redistributed and/or modified
+ * under the terms of the Apache 2.0 License OR version 2 of the GNU
+ * General Public License.
+ */
+
+#include "sdcardfs.h"
+#include <linux/fs_struct.h>
+#include <linux/ratelimit.h>
+
+const struct cred *override_fsids(struct sdcardfs_sb_info *sbi,
+ struct sdcardfs_inode_data *data)
+{
+ struct cred *cred;
+ const struct cred *old_cred;
+ uid_t uid;
+
+ cred = prepare_creds();
+ if (!cred)
+ return NULL;
+
+ if (sbi->options.gid_derivation) {
+ if (data->under_obb)
+ uid = AID_MEDIA_OBB;
+ else
+ uid = multiuser_get_uid(data->userid, sbi->options.fs_low_uid);
+ } else {
+ uid = sbi->options.fs_low_uid;
+ }
+ cred->fsuid = make_kuid(&init_user_ns, uid);
+ cred->fsgid = make_kgid(&init_user_ns, sbi->options.fs_low_gid);
+
+ old_cred = override_creds(cred);
+
+ return old_cred;
+}
+
+void revert_fsids(const struct cred *old_cred)
+{
+ const struct cred *cur_cred;
+
+ cur_cred = current->cred;
+ revert_creds(old_cred);
+ put_cred(cur_cred);
+}
+
+static int sdcardfs_create(struct inode *dir, struct dentry *dentry,
+ umode_t mode, bool want_excl)
+{
+ int err;
+ struct dentry *lower_dentry;
+ struct vfsmount *lower_dentry_mnt;
+ struct dentry *lower_parent_dentry = NULL;
+ struct path lower_path;
+ const struct cred *saved_cred = NULL;
+ struct fs_struct *saved_fs;
+ struct fs_struct *copied_fs;
+
+ if (!check_caller_access_to_name(dir, &dentry->d_name)) {
+ err = -EACCES;
+ goto out_eacces;
+ }
+
+ /* save current_cred and override it */
+ saved_cred = override_fsids(SDCARDFS_SB(dir->i_sb),
+ SDCARDFS_I(dir)->data);
+ if (!saved_cred)
+ return -ENOMEM;
+
+ sdcardfs_get_lower_path(dentry, &lower_path);
+ lower_dentry = lower_path.dentry;
+ lower_dentry_mnt = lower_path.mnt;
+ lower_parent_dentry = lock_parent(lower_dentry);
+
+ /* set last 16bytes of mode field to 0664 */
+ mode = (mode & S_IFMT) | 00664;
+
+ /* temporarily change umask for lower fs write */
+ saved_fs = current->fs;
+ copied_fs = copy_fs_struct(current->fs);
+ if (!copied_fs) {
+ err = -ENOMEM;
+ goto out_unlock;
+ }
+ copied_fs->umask = 0;
+ task_lock(current);
+ current->fs = copied_fs;
+ task_unlock(current);
+
+ err = vfs_create2(lower_dentry_mnt, d_inode(lower_parent_dentry), lower_dentry, mode, want_excl);
+ if (err)
+ goto out;
+
+ err = sdcardfs_interpose(dentry, dir->i_sb, &lower_path,
+ SDCARDFS_I(dir)->data->userid);
+ if (err)
+ goto out;
+ fsstack_copy_attr_times(dir, sdcardfs_lower_inode(dir));
+ fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
+ fixup_lower_ownership(dentry, dentry->d_name.name);
+
+out:
+ task_lock(current);
+ current->fs = saved_fs;
+ task_unlock(current);
+ free_fs_struct(copied_fs);
+out_unlock:
+ unlock_dir(lower_parent_dentry);
+ sdcardfs_put_lower_path(dentry, &lower_path);
+ revert_fsids(saved_cred);
+out_eacces:
+ return err;
+}
+
+static int sdcardfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+ int err;
+ struct dentry *lower_dentry;
+ struct vfsmount *lower_mnt;
+ struct inode *lower_dir_inode = sdcardfs_lower_inode(dir);
+ struct dentry *lower_dir_dentry;
+ struct path lower_path;
+ const struct cred *saved_cred = NULL;
+
+ if (!check_caller_access_to_name(dir, &dentry->d_name)) {
+ err = -EACCES;
+ goto out_eacces;
+ }
+
+ /* save current_cred and override it */
+ saved_cred = override_fsids(SDCARDFS_SB(dir->i_sb),
+ SDCARDFS_I(dir)->data);
+ if (!saved_cred)
+ return -ENOMEM;
+
+ sdcardfs_get_lower_path(dentry, &lower_path);
+ lower_dentry = lower_path.dentry;
+ lower_mnt = lower_path.mnt;
+ dget(lower_dentry);
+ lower_dir_dentry = lock_parent(lower_dentry);
+
+ err = vfs_unlink2(lower_mnt, lower_dir_inode, lower_dentry, NULL);
+
+ /*
+ * Note: unlinking on top of NFS can cause silly-renamed files.
+ * Trying to delete such files results in EBUSY from NFS
+ * below. Silly-renamed files will get deleted by NFS later on, so
+ * we just need to detect them here and treat such EBUSY errors as
+ * if the upper file was successfully deleted.
+ */
+ if (err == -EBUSY && lower_dentry->d_flags & DCACHE_NFSFS_RENAMED)
+ err = 0;
+ if (err)
+ goto out;
+ fsstack_copy_attr_times(dir, lower_dir_inode);
+ fsstack_copy_inode_size(dir, lower_dir_inode);
+ set_nlink(d_inode(dentry),
+ sdcardfs_lower_inode(d_inode(dentry))->i_nlink);
+ d_inode(dentry)->i_ctime = dir->i_ctime;
+ d_drop(dentry); /* this is needed, else LTP fails (VFS won't do it) */
+out:
+ unlock_dir(lower_dir_dentry);
+ dput(lower_dentry);
+ sdcardfs_put_lower_path(dentry, &lower_path);
+ revert_fsids(saved_cred);
+out_eacces:
+ return err;
+}
+
+static int touch(char *abs_path, mode_t mode)
+{
+ struct file *filp = filp_open(abs_path, O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW, mode);
+
+ if (IS_ERR(filp)) {
+ if (PTR_ERR(filp) == -EEXIST) {
+ return 0;
+ } else {
+ pr_err("sdcardfs: failed to open(%s): %ld\n",
+ abs_path, PTR_ERR(filp));
+ return PTR_ERR(filp);
+ }
+ }
+ filp_close(filp, current->files);
+ return 0;
+}
+
+static int sdcardfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+ int err;
+ int make_nomedia_in_obb = 0;
+ struct dentry *lower_dentry;
+ struct vfsmount *lower_mnt;
+ struct dentry *lower_parent_dentry = NULL;
+ struct dentry *parent_dentry = NULL;
+ struct path lower_path;
+ struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
+ const struct cred *saved_cred = NULL;
+ struct sdcardfs_inode_data *pd = SDCARDFS_I(dir)->data;
+ int touch_err = 0;
+ struct fs_struct *saved_fs;
+ struct fs_struct *copied_fs;
+ struct qstr q_obb = QSTR_LITERAL("obb");
+ struct qstr q_data = QSTR_LITERAL("data");
+
+ if (!check_caller_access_to_name(dir, &dentry->d_name)) {
+ err = -EACCES;
+ goto out_eacces;
+ }
+
+ /* save current_cred and override it */
+ saved_cred = override_fsids(SDCARDFS_SB(dir->i_sb),
+ SDCARDFS_I(dir)->data);
+ if (!saved_cred)
+ return -ENOMEM;
+
+ /* check disk space */
+ parent_dentry = dget_parent(dentry);
+ if (!check_min_free_space(parent_dentry, 0, 1)) {
+ pr_err("sdcardfs: No minimum free space.\n");
+ err = -ENOSPC;
+ dput(parent_dentry);
+ goto out_revert;
+ }
+ dput(parent_dentry);
+
+ /* the lower_dentry is negative here */
+ sdcardfs_get_lower_path(dentry, &lower_path);
+ lower_dentry = lower_path.dentry;
+ lower_mnt = lower_path.mnt;
+ lower_parent_dentry = lock_parent(lower_dentry);
+
+ /* set last 16bytes of mode field to 0775 */
+ mode = (mode & S_IFMT) | 00775;
+
+ /* temporarily change umask for lower fs write */
+ saved_fs = current->fs;
+ copied_fs = copy_fs_struct(current->fs);
+ if (!copied_fs) {
+ err = -ENOMEM;
+ unlock_dir(lower_parent_dentry);
+ goto out_unlock;
+ }
+ copied_fs->umask = 0;
+ task_lock(current);
+ current->fs = copied_fs;
+ task_unlock(current);
+
+ err = vfs_mkdir2(lower_mnt, d_inode(lower_parent_dentry), lower_dentry, mode);
+
+ if (err) {
+ unlock_dir(lower_parent_dentry);
+ goto out;
+ }
+
+ /* if it is a local obb dentry, setup it with the base obbpath */
+ if (need_graft_path(dentry)) {
+
+ err = setup_obb_dentry(dentry, &lower_path);
+ if (err) {
+ /* if the sbi->obbpath is not available, the lower_path won't be
+ * changed by setup_obb_dentry() but the lower path is saved to
+ * its orig_path. this dentry will be revalidated later.
+ * but now, the lower_path should be NULL
+ */
+ sdcardfs_put_reset_lower_path(dentry);
+
+ /* the newly created lower path which saved to its orig_path or
+ * the lower_path is the base obbpath.
+ * therefore, an additional path_get is required
+ */
+ path_get(&lower_path);
+ } else
+ make_nomedia_in_obb = 1;
+ }
+
+ err = sdcardfs_interpose(dentry, dir->i_sb, &lower_path, pd->userid);
+ if (err) {
+ unlock_dir(lower_parent_dentry);
+ goto out;
+ }
+
+ fsstack_copy_attr_times(dir, sdcardfs_lower_inode(dir));
+ fsstack_copy_inode_size(dir, d_inode(lower_parent_dentry));
+ /* update number of links on parent directory */
+ set_nlink(dir, sdcardfs_lower_inode(dir)->i_nlink);
+ fixup_lower_ownership(dentry, dentry->d_name.name);
+ unlock_dir(lower_parent_dentry);
+ if ((!sbi->options.multiuser) && (qstr_case_eq(&dentry->d_name, &q_obb))
+ && (pd->perm == PERM_ANDROID) && (pd->userid == 0))
+ make_nomedia_in_obb = 1;
+
+ /* When creating /Android/data and /Android/obb, mark them as .nomedia */
+ if (make_nomedia_in_obb ||
+ ((pd->perm == PERM_ANDROID)
+ && (qstr_case_eq(&dentry->d_name, &q_data)))) {
+ revert_fsids(saved_cred);
+ saved_cred = override_fsids(sbi,
+ SDCARDFS_I(d_inode(dentry))->data);
+ if (!saved_cred) {
+ pr_err("sdcardfs: failed to set up .nomedia in %s: %d\n",
+ lower_path.dentry->d_name.name,
+ -ENOMEM);
+ goto out;
+ }
+ set_fs_pwd(current->fs, &lower_path);
+ touch_err = touch(".nomedia", 0664);
+ if (touch_err) {
+ pr_err("sdcardfs: failed to create .nomedia in %s: %d\n",
+ lower_path.dentry->d_name.name,
+ touch_err);
+ goto out;
+ }
+ }
+out:
+ task_lock(current);
+ current->fs = saved_fs;
+ task_unlock(current);
+
+ free_fs_struct(copied_fs);
+out_unlock:
+ sdcardfs_put_lower_path(dentry, &lower_path);
+out_revert:
+ revert_fsids(saved_cred);
+out_eacces:
+ return err;
+}
+
+static int sdcardfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ struct dentry *lower_dentry;
+ struct dentry *lower_dir_dentry;
+ struct vfsmount *lower_mnt;
+ int err;
+ struct path lower_path;
+ const struct cred *saved_cred = NULL;
+
+ if (!check_caller_access_to_name(dir, &dentry->d_name)) {
+ err = -EACCES;
+ goto out_eacces;
+ }
+
+ /* save current_cred and override it */
+ saved_cred = override_fsids(SDCARDFS_SB(dir->i_sb),
+ SDCARDFS_I(dir)->data);
+ if (!saved_cred)
+ return -ENOMEM;
+
+ /* sdcardfs_get_real_lower(): in case of remove an user's obb dentry
+ * the dentry on the original path should be deleted.
+ */
+ sdcardfs_get_real_lower(dentry, &lower_path);
+
+ lower_dentry = lower_path.dentry;
+ lower_mnt = lower_path.mnt;
+ lower_dir_dentry = lock_parent(lower_dentry);
+
+ err = vfs_rmdir2(lower_mnt, d_inode(lower_dir_dentry), lower_dentry);
+ if (err)
+ goto out;
+
+ d_drop(dentry); /* drop our dentry on success (why not VFS's job?) */
+ if (d_inode(dentry))
+ clear_nlink(d_inode(dentry));
+ fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
+ fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
+ set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
+
+out:
+ unlock_dir(lower_dir_dentry);
+ sdcardfs_put_real_lower(dentry, &lower_path);
+ revert_fsids(saved_cred);
+out_eacces:
+ return err;
+}
+
+/*
+ * The locking rules in sdcardfs_rename are complex. We could use a simpler
+ * superblock-level name-space lock for renames and copy-ups.
+ */
+static int sdcardfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry,
+ unsigned int flags)
+{
+ int err = 0;
+ struct dentry *lower_old_dentry = NULL;
+ struct dentry *lower_new_dentry = NULL;
+ struct dentry *lower_old_dir_dentry = NULL;
+ struct dentry *lower_new_dir_dentry = NULL;
+ struct vfsmount *lower_mnt = NULL;
+ struct dentry *trap = NULL;
+ struct path lower_old_path, lower_new_path;
+ const struct cred *saved_cred = NULL;
+
+ if (flags)
+ return -EINVAL;
+
+ if (!check_caller_access_to_name(old_dir, &old_dentry->d_name) ||
+ !check_caller_access_to_name(new_dir, &new_dentry->d_name)) {
+ err = -EACCES;
+ goto out_eacces;
+ }
+
+ /* save current_cred and override it */
+ saved_cred = override_fsids(SDCARDFS_SB(old_dir->i_sb),
+ SDCARDFS_I(new_dir)->data);
+ if (!saved_cred)
+ return -ENOMEM;
+
+ sdcardfs_get_real_lower(old_dentry, &lower_old_path);
+ sdcardfs_get_lower_path(new_dentry, &lower_new_path);
+ lower_old_dentry = lower_old_path.dentry;
+ lower_new_dentry = lower_new_path.dentry;
+ lower_mnt = lower_old_path.mnt;
+ lower_old_dir_dentry = dget_parent(lower_old_dentry);
+ lower_new_dir_dentry = dget_parent(lower_new_dentry);
+
+ trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+ /* source should not be ancestor of target */
+ if (trap == lower_old_dentry) {
+ err = -EINVAL;
+ goto out;
+ }
+ /* target should not be ancestor of source */
+ if (trap == lower_new_dentry) {
+ err = -ENOTEMPTY;
+ goto out;
+ }
+
+ err = vfs_rename2(lower_mnt,
+ d_inode(lower_old_dir_dentry), lower_old_dentry,
+ d_inode(lower_new_dir_dentry), lower_new_dentry,
+ NULL, 0);
+ if (err)
+ goto out;
+
+ /* Copy attrs from lower dir, but i_uid/i_gid */
+ sdcardfs_copy_and_fix_attrs(new_dir, d_inode(lower_new_dir_dentry));
+ fsstack_copy_inode_size(new_dir, d_inode(lower_new_dir_dentry));
+
+ if (new_dir != old_dir) {
+ sdcardfs_copy_and_fix_attrs(old_dir, d_inode(lower_old_dir_dentry));
+ fsstack_copy_inode_size(old_dir, d_inode(lower_old_dir_dentry));
+ }
+ get_derived_permission_new(new_dentry->d_parent, old_dentry, &new_dentry->d_name);
+ fixup_tmp_permissions(d_inode(old_dentry));
+ fixup_lower_ownership(old_dentry, new_dentry->d_name.name);
+ d_invalidate(old_dentry); /* Can't fixup ownership recursively :( */
+out:
+ unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+ dput(lower_old_dir_dentry);
+ dput(lower_new_dir_dentry);
+ sdcardfs_put_real_lower(old_dentry, &lower_old_path);
+ sdcardfs_put_lower_path(new_dentry, &lower_new_path);
+ revert_fsids(saved_cred);
+out_eacces:
+ return err;
+}
+
+#if 0
+static int sdcardfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
+{
+ int err;
+ struct dentry *lower_dentry;
+ struct path lower_path;
+ /* XXX readlink does not requires overriding credential */
+
+ sdcardfs_get_lower_path(dentry, &lower_path);
+ lower_dentry = lower_path.dentry;
+ if (!d_inode(lower_dentry)->i_op ||
+ !d_inode(lower_dentry)->i_op->readlink) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ err = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
+ buf, bufsiz);
+ if (err < 0)
+ goto out;
+ fsstack_copy_attr_atime(d_inode(dentry), d_inode(lower_dentry));
+
+out:
+ sdcardfs_put_lower_path(dentry, &lower_path);
+ return err;
+}
+#endif
+
+#if 0
+static const char *sdcardfs_follow_link(struct dentry *dentry, void **cookie)
+{
+ char *buf;
+ int len = PAGE_SIZE, err;
+ mm_segment_t old_fs;
+
+ /* This is freed by the put_link method assuming a successful call. */
+ buf = kmalloc(len, GFP_KERNEL);
+ if (!buf) {
+ buf = ERR_PTR(-ENOMEM);
+ return buf;
+ }
+
+ /* read the symlink, and then we will follow it */
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+ err = sdcardfs_readlink(dentry, buf, len);
+ set_fs(old_fs);
+ if (err < 0) {
+ kfree(buf);
+ buf = ERR_PTR(err);
+ } else {
+ buf[err] = '\0';
+ }
+ return *cookie = buf;
+}
+#endif
+
+static int sdcardfs_permission_wrn(struct inode *inode, int mask)
+{
+ WARN_RATELIMIT(1, "sdcardfs does not support permission. Use permission2.\n");
+ return -EINVAL;
+}
+
+void copy_attrs(struct inode *dest, const struct inode *src)
+{
+ dest->i_mode = src->i_mode;
+ dest->i_uid = src->i_uid;
+ dest->i_gid = src->i_gid;
+ dest->i_rdev = src->i_rdev;
+ dest->i_atime = src->i_atime;
+ dest->i_mtime = src->i_mtime;
+ dest->i_ctime = src->i_ctime;
+ dest->i_blkbits = src->i_blkbits;
+ dest->i_flags = src->i_flags;
+#ifdef CONFIG_FS_POSIX_ACL
+ dest->i_acl = src->i_acl;
+#endif
+#ifdef CONFIG_SECURITY
+ dest->i_security = src->i_security;
+#endif
+}
+
+static int sdcardfs_permission(struct vfsmount *mnt, struct inode *inode, int mask)
+{
+ int err;
+ struct inode tmp;
+ struct sdcardfs_inode_data *top = top_data_get(SDCARDFS_I(inode));
+
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+ if (!top)
+ return -EINVAL;
+
+ /*
+ * Permission check on sdcardfs inode.
+ * Calling process should have AID_SDCARD_RW permission
+ * Since generic_permission only needs i_mode, i_uid,
+ * i_gid, and i_sb, we can create a fake inode to pass
+ * this information down in.
+ *
+ * The underlying code may attempt to take locks in some
+ * cases for features we're not using, but if that changes,
+ * locks must be dealt with to avoid undefined behavior.
+ */
+ copy_attrs(&tmp, inode);
+ tmp.i_uid = make_kuid(&init_user_ns, top->d_uid);
+ tmp.i_gid = make_kgid(&init_user_ns, get_gid(mnt, inode->i_sb, top));
+ tmp.i_mode = (inode->i_mode & S_IFMT)
+ | get_mode(mnt, SDCARDFS_I(inode), top);
+ data_put(top);
+ tmp.i_sb = inode->i_sb;
+ if (IS_POSIXACL(inode))
+ pr_warn("%s: This may be undefined behavior...\n", __func__);
+ err = generic_permission(&tmp, mask);
+ return err;
+}
+
+static int sdcardfs_setattr_wrn(struct dentry *dentry, struct iattr *ia)
+{
+ WARN_RATELIMIT(1, "sdcardfs does not support setattr. User setattr2.\n");
+ return -EINVAL;
+}
+
+static int sdcardfs_setattr(struct vfsmount *mnt, struct dentry *dentry, struct iattr *ia)
+{
+ int err;
+ struct dentry *lower_dentry;
+ struct vfsmount *lower_mnt;
+ struct inode *inode;
+ struct inode *lower_inode;
+ struct path lower_path;
+ struct iattr lower_ia;
+ struct dentry *parent;
+ struct inode tmp;
+ struct dentry tmp_d;
+ struct sdcardfs_inode_data *top;
+
+ const struct cred *saved_cred = NULL;
+
+ inode = d_inode(dentry);
+ top = top_data_get(SDCARDFS_I(inode));
+
+ if (!top)
+ return -EINVAL;
+
+ /*
+ * Permission check on sdcardfs inode.
+ * Calling process should have AID_SDCARD_RW permission
+ * Since generic_permission only needs i_mode, i_uid,
+ * i_gid, and i_sb, we can create a fake inode to pass
+ * this information down in.
+ *
+ * The underlying code may attempt to take locks in some
+ * cases for features we're not using, but if that changes,
+ * locks must be dealt with to avoid undefined behavior.
+ *
+ */
+ copy_attrs(&tmp, inode);
+ tmp.i_uid = make_kuid(&init_user_ns, top->d_uid);
+ tmp.i_gid = make_kgid(&init_user_ns, get_gid(mnt, dentry->d_sb, top));
+ tmp.i_mode = (inode->i_mode & S_IFMT)
+ | get_mode(mnt, SDCARDFS_I(inode), top);
+ tmp.i_size = i_size_read(inode);
+ data_put(top);
+ tmp.i_sb = inode->i_sb;
+ tmp_d.d_inode = &tmp;
+
+ /*
+ * Check if user has permission to change dentry. We don't check if
+ * this user can change the lower inode: that should happen when
+ * calling notify_change on the lower inode.
+ */
+ /* prepare our own lower struct iattr (with the lower file) */
+ memcpy(&lower_ia, ia, sizeof(lower_ia));
+ /* Allow touch updating timestamps. A previous permission check ensures
+ * we have write access. Changes to mode, owner, and group are ignored
+ */
+ ia->ia_valid |= ATTR_FORCE;
+ err = setattr_prepare(&tmp_d, ia);
+
+ if (!err) {
+ /* check the Android group ID */
+ parent = dget_parent(dentry);
+ if (!check_caller_access_to_name(d_inode(parent), &dentry->d_name))
+ err = -EACCES;
+ dput(parent);
+ }
+
+ if (err)
+ goto out_err;
+
+ /* save current_cred and override it */
+ saved_cred = override_fsids(SDCARDFS_SB(dentry->d_sb),
+ SDCARDFS_I(inode)->data);
+ if (!saved_cred)
+ return -ENOMEM;
+
+ sdcardfs_get_lower_path(dentry, &lower_path);
+ lower_dentry = lower_path.dentry;
+ lower_mnt = lower_path.mnt;
+ lower_inode = sdcardfs_lower_inode(inode);
+
+ if (ia->ia_valid & ATTR_FILE)
+ lower_ia.ia_file = sdcardfs_lower_file(ia->ia_file);
+
+ lower_ia.ia_valid &= ~(ATTR_UID | ATTR_GID | ATTR_MODE);
+
+ /*
+ * If shrinking, first truncate upper level to cancel writing dirty
+ * pages beyond the new eof; and also if its' maxbytes is more
+ * limiting (fail with -EFBIG before making any change to the lower
+ * level). There is no need to vmtruncate the upper level
+ * afterwards in the other cases: we fsstack_copy_inode_size from
+ * the lower level.
+ */
+ if (ia->ia_valid & ATTR_SIZE) {
+ err = inode_newsize_ok(&tmp, ia->ia_size);
+ if (err) {
+ goto out;
+ }
+ truncate_setsize(inode, ia->ia_size);
+ }
+
+ /*
+ * mode change is for clearing setuid/setgid bits. Allow lower fs
+ * to interpret this in its own way.
+ */
+ if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
+ lower_ia.ia_valid &= ~ATTR_MODE;
+
+ /* notify the (possibly copied-up) lower inode */
+ /*
+ * Note: we use d_inode(lower_dentry), because lower_inode may be
+ * unlinked (no inode->i_sb and i_ino==0. This happens if someone
+ * tries to open(), unlink(), then ftruncate() a file.
+ */
+ inode_lock(d_inode(lower_dentry));
+ err = notify_change2(lower_mnt, lower_dentry, &lower_ia, /* note: lower_ia */
+ NULL);
+ inode_unlock(d_inode(lower_dentry));
+ if (err)
+ goto out;
+
+ /* get attributes from the lower inode and update derived permissions */
+ sdcardfs_copy_and_fix_attrs(inode, lower_inode);
+
+ /*
+ * Not running fsstack_copy_inode_size(inode, lower_inode), because
+ * VFS should update our inode size, and notify_change on
+ * lower_inode should update its size.
+ */
+
+out:
+ sdcardfs_put_lower_path(dentry, &lower_path);
+ revert_fsids(saved_cred);
+out_err:
+ return err;
+}
+
+static int sdcardfs_fillattr(struct vfsmount *mnt, struct inode *inode,
+ struct kstat *lower_stat, struct kstat *stat)
+{
+ struct sdcardfs_inode_info *info = SDCARDFS_I(inode);
+ struct sdcardfs_inode_data *top = top_data_get(info);
+ struct super_block *sb = inode->i_sb;
+
+ if (!top)
+ return -EINVAL;
+
+ stat->dev = inode->i_sb->s_dev;
+ stat->ino = inode->i_ino;
+ stat->mode = (inode->i_mode & S_IFMT) | get_mode(mnt, info, top);
+ stat->nlink = inode->i_nlink;
+ stat->uid = make_kuid(&init_user_ns, top->d_uid);
+ stat->gid = make_kgid(&init_user_ns, get_gid(mnt, sb, top));
+ stat->rdev = inode->i_rdev;
+ stat->size = lower_stat->size;
+ stat->atime = lower_stat->atime;
+ stat->mtime = lower_stat->mtime;
+ stat->ctime = lower_stat->ctime;
+ stat->blksize = lower_stat->blksize;
+ stat->blocks = lower_stat->blocks;
+ data_put(top);
+ return 0;
+}
+
+static int sdcardfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
+ struct kstat *stat)
+{
+ struct kstat lower_stat;
+ struct path lower_path;
+ struct dentry *parent;
+ int err;
+
+ parent = dget_parent(dentry);
+ if (!check_caller_access_to_name(d_inode(parent), &dentry->d_name)) {
+ dput(parent);
+ return -EACCES;
+ }
+ dput(parent);
+
+ sdcardfs_get_lower_path(dentry, &lower_path);
+ err = vfs_getattr(&lower_path, &lower_stat);
+ if (err)
+ goto out;
+ sdcardfs_copy_and_fix_attrs(d_inode(dentry),
+ d_inode(lower_path.dentry));
+ err = sdcardfs_fillattr(mnt, d_inode(dentry), &lower_stat, stat);
+out:
+ sdcardfs_put_lower_path(dentry, &lower_path);
+ return err;
+}
+
+const struct inode_operations sdcardfs_symlink_iops = {
+ .permission2 = sdcardfs_permission,
+ .setattr2 = sdcardfs_setattr,
+ /* XXX Following operations are implemented,
+ * but FUSE(sdcard) or FAT does not support them
+ * These methods are *NOT* perfectly tested.
+ .readlink = sdcardfs_readlink,
+ .follow_link = sdcardfs_follow_link,
+ .put_link = kfree_put_link,
+ */
+};
+
+const struct inode_operations sdcardfs_dir_iops = {
+ .create = sdcardfs_create,
+ .lookup = sdcardfs_lookup,
+ .permission = sdcardfs_permission_wrn,
+ .permission2 = sdcardfs_permission,
+ .unlink = sdcardfs_unlink,
+ .mkdir = sdcardfs_mkdir,
+ .rmdir = sdcardfs_rmdir,
+ .rename = sdcardfs_rename,
+ .setattr = sdcardfs_setattr_wrn,
+ .setattr2 = sdcardfs_setattr,
+ .getattr = sdcardfs_getattr,
+};
+
+const struct inode_operations sdcardfs_main_iops = {
+ .permission = sdcardfs_permission_wrn,
+ .permission2 = sdcardfs_permission,
+ .setattr = sdcardfs_setattr_wrn,
+ .setattr2 = sdcardfs_setattr,
+ .getattr = sdcardfs_getattr,
+};
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